Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Geological Interpretation of the Pre-Eocene Structure and Lithostratigraphy of the A/M Area, Savannah River Site, South Carolina

D. E. Wyatt, R. K. Aadland and R. J. Cumbest, WSRC, Aiken, SC 29808

ABSTRACT thought to be predominantly reverse faults with possible dip-slip, or minor strike slip The geological interpretation of the structure motion. and stratigraphy of the A/M Area was undertaken in order to evaluate the effects of At least three episodes (and possibly more) of deeper Cretaceous aged geological strata and faulting are observed in the data, 1) Mesozoic, structure on shallower Tertiary horizons. The probably Jurassic to Triassic in age, faulting shallow horizons are often involved in in the crystalline basement rocks, 2) post environmental issues. Additionally, this study Cretaceous aged faulting that disrupted the attempted to evaluate the nature, extent, entire Cretaceous sediment column and 3) affects and timing of regional faults that have Paleocene or later faulting that disrupted affected the area. younger sediments. These younger structures trend to the NW and occur in an en-echelon This interpretation was completed by pattern. This pattern may affect strata to near combining 87 existing cone penetrometer surface or surface horizons. tests, 10 new cone penetrometer tests, 234 existing boring and geophysical log locations The stratigraphic information for the deeper and 21 new geophysical log locations with 22 horizons is limited due to the limited number km of new high resolution seismic data, 27 km of deep geophysical logs tied to the seismic of existing data and a 275 m by 350 m 3-D information. However, a comparison of seismic grid. Horizon information and fault regional deep logs and seismic data confirm intervals were interpreted from the seismic the near shore, fluvial to deltaic, transitional data and combined into a database with to near shore marine, depositional character of stratigraphic picks from the geophysical logs the deeper A/M Area sediments. and cone penetrometers. Regional deep boring correlations were made using the geophysical INTRODUCTION logs to constrain the seismic horizon identification. Seismic horizon to stratigraphic The A/M Combined Geological and interval correlations were made from sonic Geophysical Program was organized to information derived from geophysical logging. provide a comprehensive correlation capability between existing geological This study interpreted four major, crystalline information, newly acquired geological core, basement involved faults. The apparent oldest advanced borehole geophysical data, surface regional fault trends NNE and is identified as high resolution reflection seismic information the Crackerneck Fault. Three parallel and ground penetrating radar data within the (younger?) faults trend north. The greater A and M Areas of the Savannah River westernmost fault is identified as the Site. Specifically, the locations for all borings, MWESTA Fault and the easternmost fault as seismic, cone penetrometer and ground the Steed Pond Fault. The central fault penetrating radar data were chosen to intersects the Crackermeck Fault and is maximize correlation to existing or newly identified as the Lost Lake Fault. These faults acquired data and to compliment existing or are not thought to be single breaks in all areas ongoing environmental programs. This report but linear zones of disruption. These faults are presents an integration of new and advanced

M-1 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 data with existing information combined into Tertiary strata. Tertiary maps are made as a a comprehensive picture of the deep comparison to Aadland's (1997) work and as subsurface geology of the A/M Area. The area a tie to his interpretations. Aadland's (1997) of investigation is defined on Figure 1. The work was completed using a manual location of the seismic lines and deep borings interpretation and mapping approach. is shown on Figure 2. APPROACH TO INTERPRETATION The A/M Advanced Geological Study was a joint effort supported by several organizations The general process for geological correlation and agencies. Funding for the program was within the A/M Area follows a basement to provided through the WSRC Environmental surface "bottoms up" depositional and Restoration Department and administered by lithostratigraphic approach. For deeper strata, WSRC Site Geotechnical Services. Drilling the interpretation of geophysical log well ties and field oversight was provided by the US are made to seismic reflection events and are Geological Survey through an inter-agency used to establish base correlation horizons. agreement administered through DOE-SRS For shallower strata, older geophysical logs Environmental Division. All field work was and core are correlated with advanced coordinated through WSRC Site Geotechnical geophysical logs and core from the GCB-1,2,3 Services. Additional subcontract services were borings to establish type lithostratigraphic provided as follows: drilling by EM&TC, Inc., locations. Activities defining the general core descriptions by SAIC, field support and approach are described in order: coordination by Bechtel Savannah River, Inc., and Raytheon. Core geochemical sampling " Install borings, obtain and analyze core, was provided by Microseeps, Inc. Core from and geophysically log GCB-1, GCB-2 and the upper 150 feet of each boring was split GCB-3. Obtain spectral gamma logs in with half sent to Rutgers University for additional A/M deep cased wells P8R, detailed soils and transport analysis as part of P6R, P9R and from deep boring MMP the DOE-HQ FERC program. Borehole 4SB. geophysical data were acquired by Schlumberger Wireline Services, Inc, and "* Acquire and process A/M seismic data. Western-Atlas Wireline, Inc. Additional well logging was provided by Graves Logging " Correlate GCB's to existing basement Services. Downhole acoustic suspension boreholes using geophysical logs, core logging was acquired in GCB-1 and GCB-2 by data, field description of core, Type Well Agbabian and Associates. Surface seismic picks and Aadland (1997) picks. information was obtained and processed by the Earth Sciences and Resources Institute of "* Establish synthetic seismic data from the University of South Carolina. GCB wells correlated to lithologic picks Palynological data and additional core from core and geophysical log horizons. analysis were provided by the Department of Geological Science of Clemson University. " Correlate seismic horizons to GCB Ground Penetrating Radar data for the GCB lithologic picks. Establish fault and program were acquired and processed by structure trends through the area based on Microseeps, Inc. All data analysis, seismic offsets in the basement. Establish interpretation and correlation are provided by principal lithostratigraphic horizons on WSRC, Site Geotechnical Services and the seismic and geophysical logs. authors.

This report utilizes seismic and deep borehole geophysical data to characterize the pre-

M-2 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

"* Correlate existing A/M well data picks to The following processing sequence was lithostratigraphic picks in the GCB applied to the data: reformat SEG-2 field files borings. to SEG-Y format, apply vibroseis whitening, F-K filter, predictive deconvolution, bandpass "* Incorporate CPT data into well grid. filter, trace edit, crooked line sort, statics, bulk Correlate shallowest interpretable horizon velocity shift, velocity analysis, residual to well picks. statics, apply normal moveout, stack, bandpass filter, trace amplitude balance, apply "* Incorporate geophysical data from new AGC. shallow environmental borings to fill data gaps The dominant frequency from the high resolution survey is approximately 120 Hertz. " Generate combined correlation maps The highest frequencies observed were based on interpretable seismic horizons approximately 200 Hertz. Based on the and geophysical logs. Establish basement frequencies available, it was possible to structural trends based on seismic offsets. discern horizons approximately 4 meters in thickness. Features that were thin, or sporadic, "* Combine maps with structure into a three may have been imaged in some cases, but dimensional A/M data volume. were not interpreted in this study.

"* Develop and present cross-sections Velocity logs from GCB-l and 2, and from through the data volume. P8R and P9R, were used to construct synthetic seismic sections tied to stratigraphic horizons. section from GCB-1 "* Interpret data. The synthetic seismic tied to seismic line A-5 is shown in figure 3. Using the synthetic seismic ties, it was SOURCES OF INFORMATION possible to identify specific reflection horizons on the seismic lines as specific Nine high resolution reflection seismic lines were obtained to support deep mapping. The defined stratigraphic horizons. The crystalline Cape Fear location of these lines are shown on Figure 2. basement reflector, Top of Formation, Top of Middendorf equivalent In addition to these lines, three existing zone, and in some cases, the McQueen Branch regional seismic lines were also utilized. These These location of these lines are also shown Confining Unit were interpretable. regional unconformities or on Figure 2. surfaces represent eustasy related sequence boundaries and generally represent an acoustic impedance Field data were acquired using an OYO DAS zone detectable by the seismic technique. In 1 signal enhancement seismograph operating horizons in 96 channel mode. 40 Hz OYO geophones only a few cases were shallower were used in geophone strings having 3 interpretable. phones per string. The energy source BACKGROUND GEOLOGY consisted of an IVI MiniVIBE® remotely triggered vibrator sweeping from 50 to 200 Figure 3 is the generalized stratigraphic Hz. In general, an asymmetric split spread column for the Savannah River Site region. acquisition geometry (24-gap-72 spread) was The depositional environments and sediment utilized, with shot and geophone spacings of character for GCB-1, located in the center of 1.5 and 3.1 meters depending on the seismic the study area and thought to be line. representative, are shown on Figure 4a. Figure 4b shows the tie between key bomgs GCB-1, 2, and 3. A detailed discussion of the

M-3 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 stratigraphy and deposition is found in Fallow in Stephenson and Stieve (1992) is also and Price (1995) and Aadland et al., (1995). assumed. Any subsequent faulting within the Parts 1 and 2 of the Advanced A/M Geology area is assumed to be consistent with the Study (Wyatt et al., 1997 a and b) discuss the Crackerneck Fault or associated with the post data derived from the ground penetrating depositional stress fields. The conceptual radar, cone penetrometers and the geophysical model assumes no preferred age restrictions characterization of borings GCB-1, 2 and 3. on structural features. The presence of faults, fractures and folds are anticipated. A conceptual model of the anticipated geology in the region of the A/M Area provides an The description of the sediments encountered intellectual framework to interpret the in GCB-1 and described on Figure 5 verifies borehole geophysical and seismic data. The the basic conceptual model. basic model should be consistent with known regional geology as described in established STRATIGRAPHIC INTERPRETATION scientific literature. As data are evaluated against the model, an iterative thought process Geophysical logs and core data from shallow will allow features to be interpreted within the borings and wells are the dominant source of framework, or will suggest that modifications data within the A/M Area. Few borings need to be made in the model. If there are penetrate depths greater than 100m (330 feet) highly unusual features that violate the and most logs terminate within the Lang character of the anticipated geology within the Syne/Sawdust Landing Formation (near the model, then a data "bust" may be indicated, or Paleocene-Eocene contact) and are too new information may be present to advance shallow for direct correlation with the seismic the known geology within the area. information. To allow for direct correlation with the higher quality information from the The conceptual model of the anticipated deep borings, the geophysical logs and core deposition environment within the A/M Area data from the shallow wells were tied to the is a near shore to delta plain environment. stratigraphy determined from the deeper Therefore, sediments associated with a near borings. The correlation of the shallow shore deltaic, fluvial and near shore marine borings is discussed in Aadland (1997) and are anticipated. Variations in facies elsewhere in this guidebook. architecture associated with depositional processes in these environments are also Cone penetrometer soundings generally anticipated. Facies architecture variations extend to depths of approximately 50m (150 include "fining upwards" or "coarsening feet) or approximately to the top of the upwards" sedimentary sequences in a Warley Hill Formation and occasionally reach transgressive-regressive system. Sediments the "green clay" bed within the formation. The associated with near shore, littoral zone and Friction Ratio's from the cone penetrometer beach environments may be highly variable data were correlated with the geophysical logs both laterally and vertically. The model from the shallow borings. See Syms et al., in assumes that depositional sequences within this guidebook for a further discussion of the the area are consistent with those published by CPT. Fallaw and Price (1995) and anticipates the regional unconformities present in these INTERPRETATION OF DEEP COR sequences to also be present in the area. RELATION BORINGS

Structural features within the area are Lithostratigraphy assumed to be consistent with the known post depositional regional stress fields. The The interpretation of the GCB borings was presence of the Crackerneck Fault as defined guided by the need to establish relationships

M-4 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 between core derived and geophysically character of the saprolite varies in each derived geology. Additionally, the correlation boring. In GCB-l the saprolite contact is between the geophysical log interpretation and defined by a sharp change between a well surface derived seismic data is important to indurated sandy/silty clay to gray-green clay understanding the overall A/M, and SRS, with numerous iron oxide stains. The color geological setting. The GCB-1,2,3 varies from gray-green to brown-red. In GCB interpretation will be presented as a unit by 2 the saprolite is a brown to red mottled clay unit correlation comparing core geology and grading into a dense, massively foliated olive log derived depositional signatures. green clay while in GCB-3 the saprolite is a Hydrostratigraphic nomenclature follows that bluish gray to off white, well indurated clay. of Aadland et al. (1995). Stratigraphic nomenclature and environmental comparisons Cape FearFormation (Top CF) are from Fallaw and Price (1995) and Reineck and Singh (1980). Log interpretations follow The Cape Fear Formation generally thickens suggestions from Schlumberger (1989) and towards the southeast from GCB-3 to GCB-1. Serra (1985). The overall lithology of the formation consists of interbedded gravel, sands and clays of Saprolite and Basement (Pzm/Sap and varying colors and sizes. Rock fragments and Acoustic Basement) angular sands suggest that the Cape Fear Formation was deposited near its source. Crystalline basement lithologies are similar There are generally three member sequences, across the GCB-1,2,3 area. In GCB-1, an olive alternating coarsening and fining upwards, to gray/green weathered chlorite schist that define the formation and that are most overlies a highly fractured bluish gray gneiss. developed in GCB-1. The overall geophysical The thickness of the schist is approximately log pattern of the sequences, which matches 47 feet (14.3 m) and a distinct contact is the field core descriptions, suggests that each present between the schist and gneiss. In unit within the formation is a lag channel, GCB-2 and 3, only the chlorite schist interval shoaling deposit fill with pebbles and heavy was sampled which had a similar appearance sands grading into finer sands with to the schist of GCB-1. Fractures within the interspersed clays. This interpretation is schist of GCB-1 have an approximate consistent with the description in Aadland et northwest strike orientation with a dip varying al., (1995) and Fallaw and Price, (1995). between 13 and 27 degrees. Fractures and quartz veins within the gneiss appear to have a Within the Cape Fear and at the basal northeast strike orientation and gentle dips, Middendorf, rock resistivity values and deep however, only the upper few feet of the gneiss versus shallow curve separation (an indicator were sampled for dip information. No oriented of relative permeability) decrease rapidly. The dip or strike information is available for GCB overall neutron porosity drops from an 2 and 3. All of the crystalline basement average of approximately 35% to lithologies encountered in GCB-1,2 and 3 approximately 20%. The low relative were expected as referenced in Cumbest and permeability and porosity suggests tighter Price (1989). formations. The lower resistivity values are associated with higher concentrations of The top of basement contact is the first heavy minerals and interstitial waters are more contact with the highly weathered and mineralized than shallower aquifers. Overall, fractured saprolite. Generally, the saprolite the Cape Fear and saprolite are indurated with increases in thickness from GCB-2 and 3 to lower permeability, forming the Appleton GCB-1 from approximately 13 feet (4 m) in Confining Unit. GCB-3 and 15 feet in GCB-2 to approximately 32 feet (9.8 m) in GCB-1. The

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MiddendorfZone (Top Mid) throughout the interval. Spectral gamma peak to peak correlation, indicating regional clay The Middendorf Zone (formerly Formation) units, are possible to track across the borings. gradually thickens towards the southeast from These clays are probably localized maximum GCB-3 to GCB-1. There are correlatable flooding surfaces, while the basal clays, packages of sediments across the formation similar across the area, were deposited in a but it is difficult to correlate specific sand or near shore marine environment. The clay units across the area defined by GCB-1, interbedded sands and clays, often with 2 and 3. Channel and sheet type sands are interspersed iron staining and heavy minerals, interbedded with indurated clays suggesting a is suggestive of a fluvial to upper delta lower delta plain depositional environment. depositional environment. Many of the sand units in GCB-1,2,3 appear to alternate between fining and coarsening The MqBCU is a sequence of three principal upwards suggesting that they are marine clays and silty clays occurring in a 40 foot influenced channels or bars. Spectral gamma (12.2 m) interval separated by clayey to silty data, when combined with field core sands. Each of the three units is approximately descriptions and lab core analysis, suggests 10 to 15 feet (3.0 to 4.6 m) thick with the that there are few clays of significant lower unit having the most consistent clay thickness within the formation. Generally, the content and thickness. Many of the sands clays are thin and less than one meter thick. within the MqBCU are moderately sorted and Numerous heavy minerals and micas, as well sub-angular with a consistent presence of as fine grained sands with clay balls, generate micas suggesting that these sands are fluvial a spiked appearance of the gamma curve and deposited near their source. The clays also which may be interpreted as numerous consistently have micas presence, suggesting interspersed clays. Focused or Induction that the clays and the sands are both fluvial Resistivity data suggests that there are deltaic to near shore sub-tidal. numerous high permeability zones separated by numerous 'tight' streaks of clay or silt to The upper zone of the Black Creek is variable silty-sand. These zones also suggest that there across the region of the GCB borings. In are non-correlatable sand bodies within the GCB-2, the interval consists principally of formation with variable permeability, interbedded clays and sands in beds averaging therefore, tracking groundwater movement 5 to 7 feet (1.7 to 2.1 m) thick. This 'serrated' within the Middendorf within the A/M Area depositional style is common along the would be extremely difficult. margins of bar-finger sands (Busch and Link, 1985). In GCB-1 and 3, the dominant Black Creek Formation (Top BC) lithology in the upper zone is sand with thin interspersed silt and clay intervals. The sands The Black Creek Formation in borings GCB are dominantly moderately to well sorted, tan 1,2,3 may be described in terms of an upper to cream in color, and sub-angular to sub and lower member, possibly two sequences, rounded. Micas are present and sometimes separated by the McQueen Branch Confining abundant with rare heavy minerals. The sand Unit (MqBCU) regional aquitard. Both upper is 75 feet (22.9 m) thick in GCB-3 and 37 feet and lower zones have geophysical log and (11.4 m) thick in GCB-l. These sands are not core characteristics that define them as massive but consist of stacked bar finger, bar primary regional aquifers. axis and barrier sequences with dips (in GCB 1) of 2' to 120 to the northwest in the upper The lower zone lies unconformably over the units, to 14' to 210 to the south-southwest in Middendorf and consists of interbedded thin the middle sands followed by 150 to 290 dips clays and sands occurring, more or less, to the northeast in the lower sand units. The randomly distributed and uniformly spaced average dip direction is to the south. The

M-6 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 alternating dip directions are indicative of landward in GCB-3 and more seaward in near shore influence and the measured dips GCB-1. It is possible that the are probably alternating barrier or dune Cretaceous/Tertiary boundary (K/T), and foreset beds. contact with the Paleocene, is present at the basal contact of the clay unit immediately Samples for palynological analysis were overlying the 'C' sand. The presence of obtained from the GCB-1 boring in a dark, pebble lag layers and heavy minerals may organic rich clay from a depth of 439.5 feet define this time sequence marker. (134 m, Figure 4a) at the base of the upper sand unit and top of the MqBCU. Crouch Branch Confining Unit (Top CBCU Palynomorphs were present indicating a late to Base CBCU) Campanian to early Maestrichtian age. The spores, pollen, plant cuticle, wood fibers and The Crouch Branch Confining Unit varies in inertinite, plus a lack of marine algae, thickness and clay content from approximately indicates that this interval is non-marine 17 feet (5.2 m) of thin and sparse clays in (Christopher, personnel communication, GCB-3 to 44 feet (13.4 m) of thick silts and 1996). clays in GCB-2 to 50 feet (15.2 m) of silty clays and clays in GCB-1. The clays tend to Steel Creek Formation (Base of CBCU to be a white to light gray, plastic kaolinite with Top BC) thinly laminated purple mineral horizons. The CBCU in GCB-1 is predominantly kaolinitic The Steel Creek Formation is defined from the clay with only minor interspersed laminae of base of the Crouch Branch Confining Unit silty clay. In GCB-2, thin lamina of heavy (CBCU) to the top of the Black Creek minerals and silts are interspersed within the Formation. Dominant lithologies consist of clays. Thin sands within the unit often have micaceous clays interbedded with sands, sands heavy minerals and abundant micas. Thin and silty sands interbedded with thin clays and zones of cemented iron laminae are also pebble zones. Micas, including angular grains, present. In GCB-3, only thin clay units are are present throughout the interval and iron present interspersed with silty clays, sandy staining is common. In the basal 50 feet (15.2 silts and sands. Numerous lamina with iron m) of each boring, clay content increases and staining and heavy minerals are present. The alternates with fine grained silty sands. The thin sands tend to grade into pebbles and clay overall dip direction is generally random. balls. The thin clays, clay balls and shoaling Sands appear to be more prevalent in the sands units in GCB-3 suggest that GCB-3 upper portions of the Steel Creek and exhibit CBCU sediments were deposited in a fairly morphologies similar to distributary barrier high energy, near shore, possibly intertidal and bar sequences. In GCB-1, these sands zone, transitioning into a subtidal to delta generally fine upwards, and exhibit varying distributary depositional environment in GCB dip angles from up to 200 northwest to 120 1. southeast and 180 northeast. The 'C" sand of Aadland et al., (1995) is present in all wells This unit, which consists of parts of various and gradually varies from a coarsening formations, forms the principal confining unit upwards distributary bar finger and delta lobe across the SRS; therefore is discussed in detail sands (Busch and Link, 1985) in GCB-l and 2 as it controls downward contaminant to a more marginal bar finger sand or delta movement. Permeability variations in the lobe in GCB-3. The remaining sands in the CBCU, determined from magnetic resonance upper portion of the Steel Creek are geophysical logs, are observable in GCB-1. depositionally similar to the 'C' sand but tend The interval from 240 feet (73.2 m) to 250 to be more tidal in GCB-3. In general, the feet (76.2 m) is a well indurated and mottled sands of the Steel Creek appear to be more clay. Permeability average less than 200

M-7 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 millidarcies. From 240 feet (73.2 m) to 265 feet (80.8 in), subsurface, the measured The lower 10 feet (3 m) (230 feet (70.1 m) to permeabilites increase to greater than 1 darcy. 240 feet (73.2 m) subsurface) of the LS/SL All clay within this interval is well indurated has an average permeability that exceeds I and without other noticeable features. Various darcy. This interval is a well indurated clay color changes, suggesting changes in the with iron oxide staining and containing some geochemical makeup of the clays, form pyrite. The measured permeability in this numerous lamina throughout the section. The interval is probably due to microfracturing and magnetic resonance tool is probably imaging the horizontal character of the iron oxide the horizontal permeability associated with lamina. This interval is capped by a low these lamina. In the base of the CBCU, from permeability (less than 10 millidarcies) thinly approximately 265 feet (80.8 m) to the top of bedded clay and silty clay. Overlying this the Steel Creek Formation at 290 feet (88.4 m) clay, is a zone that transitions into a high subsurface, the permeability decreases from permeability (greater than 1 darcy) that approximately 500 millidarcies to zero. This probably corresponds with the Lang interval is also a well indurated clay with Syne/Sawdust Landing unconformity. In fewer lamina, grading into a silty, micaceous GCB-1, the combination of the underlying clay. At 290 feet (88.4 m) subsurface, the CBCU and the high permeability associated magnetic resonance permeability increase with the LS/SL unconformity create the zone dramatically in the sands of the Steel Creek with the highest TCE concentrations. The Formation. ability to track and map the Lang Syne/Sawdust Landing Formations and the Lang Syne/Sawdust Landing Members (Top unconformity zone suggests a way to possibly LS/SL to Top CBCU) track halogenated solvents.

The Lang Syne and Sawdust Landing The following stratigraphic units, although Formations (refer to Aadland et al., 1995 and Eocene in age, are discussed for continuity Fallaw and Price, 1995 for nomenclature with the work of Aadland in this guidebook. discussions) are not lithologically differentiated within the A/M Area of the CongareeFormation (Top Congaree) Savannah River Site. Within the area of GCB 1,2,3, these formations vary in thickness Unconformably overlying the Lang between 28 feet (8.5 in) in GCB-3 to 46 feet Syne/Sawdust Landing Formations are the (14 in) in GCB-2 and 12 feet (3.6 m) in GCB assemblages of Early Eocene sediments that 1. Two distinct, lithologically different and comprise the Fourmile Formation. It is correlatable, members are seen in each boring. lithologically difficult to distinguish these The basal member of the Lang Syne/Sawdust specific formations from the overlying lower landing is a lower bar to delta sheet sand that middle Eocene Congaree Formation and the thins downdip to the southeast. The upper entire interval is generally referred to as the member is a silty clay to clay coarsening Congaree Formation (Aadland et al., 1995). upwards into a delta front sheet sand that has Generally, the lower sands within the interval, the greatest thickness in GCB-2. The silty when present, are considered equivalent to the sand interval in the upper member in GCB-1 Fourmile Formation while the upper sands, appears to be the distal edge of the delta front. when present, are a portion of the Congaree Overall, the general dip of the LS/SL Formation. sediments is south-southeast. The sand interval in the upper member appears to be a Generally, the depositional character of the bar sand that is probably regressive, intertidal Congaree in GCB-l,2,3 is similar. There is a and defines the Lang Syne/Sawdust Landing slight increase in formation thickness from regional unconformity.

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GCB-3 towards GCB-1 and 2 suggesting a Warley Hill consists of a sand with seaward dip. The lithology of GCB-2 and 3 interspersed iron oxide modules overlying a consists of sands, medium to coarse grained, silty sand to thinly laminated silty clay. The interspersed with thin indurated clays. GCB-2 silty clay, and to some extent the silty sand, is dominantly sands with thin silts and a few form the Gordon Confining Unit with clay lamina and GCB-3 is dominantly sand measured log permeability of less than 50 with thin clay and iron stained lamina. In millidarcies. This clay interval is regionally GCB-1, there are lithified sand intervals 1.2 to extent and is thought to represent a maximum 1.6 inches (30 to 40 mm) thick and siliceous flooding surface. Sands within the upper sandstones up to 2 inches (50 mm) thick. Well portion of the formation generally have indurated clays are present as a central unit permeability on the order of 100 to 200 md. In within the formation and are approximately 10 GCB-1, the dip directions within the Warley to 15 feet (3 to 4.6 m) thick associated with Hill are varied. silty clays and clayey silts. In GCB-2, the Warley Hill sediment character Permeability zones are variable within the is similar to GCB-1 but the formation is Congaree. In GCB-l, generally, within the locally exposed on the surface and has been formation, cleaner sand zones have higher affected by near surface processes. In GCB-3, permeability, approaching 500 millidarcies, the formation is generally sandier than GCB and silty to clayey sands have permeability 1, and lacks the thin clay lamina and silty less that 5 millidarcies. Traces of PCE and sands that constitute the confining unit. TCE are generally seen in the thin sands that are immediately above the well indurated Correlation With Other Deep Borings clays. The deep correlation borings used to calibrate A shallow shelf to shoreline environments of the seismic data are GCB-1, 2, 3 and P8R, deposition for the Congaree is evidenced by P9R, MMP4-SB and MBC08ASB. The the dip directions in GCB-1. Basal Congaree locations for these boring are shown on Figure sands (possible Fourmile or Fishburne 2. The stratigraphic horizons from GCB-1, 2, Formation equivalents) generally rotate from a 3 were used to correlate the horizons from low angle south-southwest dip through a P8R, P9R, MMP-4-SB and MBC08ASB. The westward to north-northwest dip direction geophysical data from all of these borings with an angle of 60 to 8' to a low angle (except MCB08ASB) are calibrated to northeasterly dip. The upper sand unit international standards and were used to (probable Congaree Formation equivalent) has correlate and verify all geophysical logs very high, up to 240 dips generally striking to within the A/M Area. Data were correlated the northeast. The upper sand interval is most using LandMark® and TerraSciences® indicative of a possible dune sand with the geological software. Figure 6 is a structural high angle dips suggesting foreset bedding. correlation panel showing the stratigraphic The basal sands are most indicative of deltaic horizons for these deep correlation wells. This to near shore barriers and bars. panel is flattened on an elevation of 97m (300 feet) relative to mean sea level. The Warley Hill Formation (Top WH) stratigraphic horizons are those utilized to map specific intervals within the study area. In The Warley Hill Formation is present in GCB general, only the Late Cretaceous horizons are 1, 2 and 3. In GCB-3, the formation is visible on the seismic data. generally geophysically indistinguishable from the over and underlying units, however, The figure 6 correlation panel follows no a subdued gamma pattern is similar to the particular strike or trend except that P8R, patterns from GCB-1 and 2. In GCB-1, the GCB-1 and P9R are in the central portion of

M-9 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 the A/M Area with P8R being more westerly, non-deposition occurred during Middendorf GCB-2 is in the southeastern area, MMP-4SB time. The upper Black Creek also thins and GCB-3 are in the eastern area and suggesting reactivation of the upward sense of MCB08ASB is in the northern area. motion during Black Creek time. Therefore, the correlation panel proceeds from the west central portion of the study area The Steel Creek thins in GCB-3 suggesting southeastward, westward and then to the erosion or non-deposition at this location north. These logs are used only to evaluate the during or in post Steel Creek time. The overall relationship of the stratigraphic units across thickness of the Steel Creek to Lang the study area and, along with their velocity Syne/Sawdust Landing interval including the and other data, provide a framework for clays of the early Paleocene, may be described interpreting the seismic data. Also, as a transitional strata. The Lang "flattening" on stratigraphic horizons allows Syne/Sawdust Landing shows only minimal for the relative interpretation of depositional effects from the underlying structure (on the character and relative fault motions to be order of 3 to 4 meters). The basement related made. structures show approximately 30 to 40 meters of relief. This panel demonstrates several interesting features. All horizons, except the McQueen The Congaree and Warley Hill Formations are Branch Confining Unit, from MCB08ASB in fairly uniform in thickness. The sag seen in the north to P8R in the southwest, show the the Warley Hill in GCB-3 is contrary to southerly basinal dip. There are offsets in regional dip and is probably associated with crystalline basement, particularly associated the basement structure. The sag seen in GCB with GCB-3,P9R and GCB-1, that are 1 may also be associated with a basement continuous through to the Lang Syne/Sawdust related structure. The interval from the Santee Landing unconformity. In GCB-3 and unconformity to the Warley Hill unconformity MCB08ASB the regional structure does not is generally uniform but thickens in GCB-1. track as well as in the wells to the south and The Santee surface is also a cut and fill west and it is possible that there is another surface and suggests that the motion erosion event beveling the structure prior to documented in GCB-1 was not active in post the Lang Syne/Sawdust Landing event, and Santee time. probably occurring at the Cretaceous/Tertiary boundary. In well P8R, the structure reverses Interpretation of Seismic Data from a general downward sense of motion to an upward sense of motion in the lower Black The seismic data were interpreted using the Creek Formation. It is possible that well P8R LandMark® software system according to the cuts a reverse fault in the Middendorf/Black following approach. Each processed seismic Creek intervals. This is supported from line was plotted on the regional map with historic anecdotal evidence that the lower associated deep correlation borings. Available intervals of well P8R are deviated along a borehole sonic data from the deep borings, fault plane. (from GCB-1, 2, 3, P8R, P9R and MMP-4 SB), were utilized to generate a synthetic The Middendorf, Black Creek (including seismic image, using the GMA® seismic McQueen Branch Confining Unit) and Steel software, for the area adjacent to the borehole. Creek Formations (generally, the entire The synthetic seismogram ties well derived Cretaceous section) are fairly uniform in stratigraphic horizons to specific seismic thickness across the area. The Middendorf horizons and allows for the interpretation and thins (or the Cape Fear may be missing) in tracking of stratigraphy and structure across a P9R suggesting that the upwards motion noted seismic profile. Figure 5 is the synthetic in basement was present and either erosion or seismogram from GCB-1.

M-10 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

The synthetic seismogram for each well was However, the channels or other feautures are correlated with the adjacent seismic profiles. not highlighted on the seismic data and are not Horizons on the seismic profile that were discussed in detail in this document because correlative with the synthetic well tie were they will require a more intense interpretive traced across the profile. In general the effort using seismic signal attribute data (such crystalline basement reflector (rock), the Cape as instantaneous frequency and phase). If Fear/Middendorf contact (top Cape Fear), the obvious channels are observed in the data, basal Black Creek/Middendorf contact (top then they are mentioned. The criteria used to Middendorf), and McQueen Branch Confining define a channel are discussed in Reineck and Unit horizons were interpretable stratigraphic Singh (1980) and include: 1) an obvious, events. The Lang Syne/Sawdust Landing incised erosional surface, 2) the presence of intervals were not consistently discernible cross-bedding, 3) presence of point bar across the seismic data. In a few areas, the sequences, 4) an apparent thalweg, and 5) Warley Hill interval appeared to be alternating sand/clay/gravel bars. interpretable, however this occurred too sporadically to map. In general, no shallower Individual 2-D Seismic Line Interpretations horizons were obviously interpretable on the seismic data. Figures 7 and 8 show Representative seismic data are shown on representative seismic data with stratigraphic figures 7 and 8 and the overall pattern and horizons and faults interpreted. distribution of seismic coverage is shown on figure 9. Figure 9 also shows the relative Stratigraphic horizons were traced from well seismic depths in time and the trend of the tie points following dominant seismic major faults in the area. amplitude events. In areas where the horizons were difficult to track, no interpretations were All seismic data are interpreted for faulting made. In many cases, one stratigraphic and stratigraphic horizon markers, as horizon may be interpretable while others determined from the synthetic seismic data were not. The two way travel time values for shown on figure 5. For all lines, the yellow each seismic shotpoint with an interpreted horizon represents the top of "rock" or the horizon were tracked, converted to depth surface of the unweathered Paleozoic based on the synthetic seismograms, and crystalline basement. The dark red horizon transferred to EarthVision 4.0 for mapping. marker is the contact of the Cape Fear Formation (Coniacian/Turonian, 90 mybp) Faulted intervals were determined using the with the overlying Middendorf Formation. criteria of Sheriff (1982) and Campbell (1965) The pink horizon is top of the Middendorf and include: 1) abrupt reflector terminations, Formation (Campanian/Santonian, 82 mybp) 2) direct fault plane reflections, 3) presence of or contact with the overlying Black Creek diffractions especially at a termination, 4) Formation, a regional unconformity. The visible drag and rollover, 5) correlations of orange horizon is the top of the confining unit reflectors across a fault plane and possibly 6) or clay package that has been designated as loss of coherency beneath a fault plane or the McQueen Branch Confining Unit distorted dips seen through the fault plane (Aadland et al., 1995). This horizon lies (fault shadow). Using these criteria, faults within the Black Creek Formation and may were defined on the seismic profiles in represent the Campanian/Maestrichtian LandMark® and transferred into EarthVision® contact, another major unconformity. These for mapping. four Cretaceous aged horizons appear consistently on all of the data and are used as It is probable that channels and other the principal subsurface horizons for seismic depositional features exist within the A/M mapping. Area and are imaged on the seismic data.

M-I1 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

On all seismic lines, only five possible faults orange McQueen Branch horizon are shown (reference Figure 9). Faults, and demonstrates a fault propagation fold projection lines, designated in red refer to the geometry. Folded and flexed sediments are Crackerneck Fault (CNF). Faults in green apparent from the McQueen Branch to refer to the MWESTA Fault and faults in pink approximately 100 ins, although these events refer to the Lost Lake Fault. Fault segments in are not traceable across the data. The overall orange refer to the Steed Pond Fault. Yellow sediment wedge thickness appears to increase fault segments are faults with no assigned to the southeast as expected. Changes in orientation or name. These faults may have amplitude laterally along horizons to the limited extent, may be associated with a southeast, particularly in the lower Black named fault, or their extent may not be Creek, may indicate the stratigraphic or facies determined from our seismic coverage. The changes associated with shallow channeling, angle of the fault segments posted on each other near shore or fluvial processes. This line seismic line is somewhat arbitrary since our intersects five of the A/M lines CNF-1, A-3, data were not designed to image structure A-lA, A-2 and SRS-7. In all cases, the below the crystalline surface. interpreted horizons match those from the other lines and the data are consistently tied. Line SRS-1 is shown on figure 7 and is discussed as a representation of the remaining 3-Dimensional Seismic Data seismic data.. This approximate north-south line is the definitive data for the existence of A three dimensional seismic survey was the CNF, shown as a red line. Regional dip obtained immediately southeast of line MCB from this data is southerly at approximately 1. Results are shown in figure 10. The 1.5%. The vertical offset in the CNF is rectangular cube was obtained over a surface approximately 12 ms two way time (TWT), or area of approximately 275 meters by 352 30 to 35 meters, on the basement horizon. The meters using 120 cross-lines and 154 inlines horizontal extent of the offset is across two with a 2.2 meter spacing (a 2.2 meter bin shotpoints or approximately 35 meters. size). An IVI MiniVibe vibratory source was Compensating faults, or more recent faults, used. In general, best results were obtained associated with the CNF, are shown in yellow. from 200 ms and deeper. Little to no data These faults may accommodate the stresses were interpretable above 200 ms. associated with the CNF. The northwestern fault (in yellow) is associated with the green Figure 10 shows time slices, in relative dashed line which is the projection of the amplitude, through the data cube. Each time AMWESTA fault, therefore, these two faults slice has the time and stratigraphic interval are probably the same. The fault noted in pink noted. The projection and strike of the Lost to the southeast of the CNF is the Lost Lake Lake Fault, with relative sense of motion, Fault and the dashed pink lines are the which is projected through the area from the projections of this fault through the area from 2-D seismic lines, is included for reference. other seismic data. The basement reflector, in The 325 ms time slice corresponds to the yellow is consistently tracked by the dark red approximate top of "rock" or crystalline Cape Fear marker horizon except immediately basement. A pronounced negative amplitude northwest of the CNF where there is an (purple) feature is seen in the southeastern apparent increase in thickness of the Cape portion of the cube, surrounded by a higher Fear, or where there may be remnant Triassic amplitude event. This low amplitude feature is trough sediments. The pink horizon is the the same low amplitude feature seen Middendorf Formation contact with the Black surrounding the heart shaped high amplitude Creek Formation. Over the faulted intervals, it feature seen in the 320 ms time slice is difficult to track a consistent horizon and (approximately 20 meters shallower). disturbed or eroded sediments are seen. The Therefore, the low amplitude event is higher

M- 12 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 by 5 ms and has the same approximate sense for example, may be interpreted as a channel of motion as the Lost Lake Fault predicts. At meander, however, inline evaluation suggests 340 ins, approximately 40 meters below the that the reflection event is structurally top of "rock", the trend of the Lost Lake Fault controlled. The lack of channels and definitive bisects a phase change (of about 1800) event structures is probably a function of the small presumed to be the same for the shallower size of the 3-D cube and the representative horizons. It is not evident that this relationship subsurface sampled. exists upwards through the cube, although there are notable changes across the projected strike of the Lost Lake Fault. The features that DISCUSSION trend northwest to southeast in the 260 ad 270 ms time slices may be faults at oblique angles Mapping to the main basement trend. This is supported in the time slices at 256 and 260 ms. The NW Seismic horizon picks, converted from time to SE trending high amplitude reflector in the depth using the synthetic information from eastern central portion of the cube in slice 260 GCB-1, GCB-3, P8R and P9R were combined ms is the same high, but weak, reflector in the with the stratigraphic picks from the central west portion of the cube, between geophysical logs and CPT's (where inlines 40 and 60 of time slice 256 ms. This applicable) to create the database for mapping. implies a general up to the west sense of Mappable horizons from the seismic data motion, however, the trend of the features is include the acoustic crystalline basement oblique to the trend of the Lost Lake Fault. It ("rock"), Cape Fear, Middendorf and is interesting to note that the trend of these McQueen Branch surfaces. In a few cases the features parallel the NW to SE trending sides Black Creek horizon was observable but these of the high amplitude basement feature seen in were too sporadic to adequately map. Data the 320 and 325 ms time slices. This suggests were forced, using a static shift and that the basement trend of the Lost Lake Fault velocity/depth corrections, to match actual zone is NE to SW but individual faults within depths from the deep correlation borings. The the zone may be parallel or data from each horizon were then mapped. For synthetic/antithetic to the basement trend. the seismically derived horizons, the projected This also suggests that individual basement major fault planes (MWESTA, CNF, Lost fault blocks may be small in size along the Lake and Steed Pond) were included in the fault zone (approximately 150 by 150 meters mapping database and used to constrain in the case of the high amplitude feature in the contours adjacent to the faults. Each mapped basement). It is not evident how far the fault surface is discussed. extends into basement on the 500 ms time slice. These data are basically random and out Stratigraphic intervals from shallower of the range of the seismic investigation. horizons are discussed in Aadland (this guidebook). The previous intervals from the It should also be noted that there are linear, work of Aadland (1997) were reviewed and amplitude coherency events in the 3-D data. modified according to the regional deep These features are often associated with boring correlations. Stratigraphic picks from structural features such as fault cuts, and are available cone penetrometer data were also associated with sedimentary features such combined with new and existing information. as channel boundaries. Within the useable 3-D These stratigraphic "picks" were incorporated data, there are no obvious channel features or into Earth Vision® 4.0 for mapping. Shallow unique facies changes, although it is possible mapped horizons include the top of Black that there are facies changes associated with Creek Fm., top of Steel Creek Fm., Lang the slopes of the faulted blocks. The trend of Syne/Sawdust Landing unconformity, and the low amplitude events in time slice 256 ms,

M-13 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Warley Hill unconformity. A surface elevation map is included for discussion. Top of Middendorflnteval

Top of CrystallineBasement ("rock") The structural top of the Middendorf interval is shown on figure 13. The central structure is Figure 11 is the surface of the crystalline present with an overall elevation change basement. The dominant faults projected across the area of approximately 50 meters. through the area and seen on figure 9 are Generally the formation dips to the south. The shown. It is obvious that the area in the center structural affects of the Crackerneck and of the map is complexly disturbed. The area Steed Pond Faults are immediately obvious. between the Steed Pond Fault (most eastern Map edge effects are great, particularly the fault) and the Crackerneck Fault is structurally steep structural change to the north between higher than areas east and west. Deeper the Crackerneck and Steed Pond Faults. A basement is to the southwest and westward of ramp like structure may be present from the the CNF and MWESTA faults. The overall central high eastward to the Steed Pond Fault. maximum structural elevation change across Structure is more complex west of the the area is approximately 70 meters. Regional Crackerneck/Lost Lake Faults. dip is to the southeast. Structure and dip on the northwest, northern, northeast and Top of McQueen Branch Unit southeast, and possibly the southwest edges of the map are influenced by map edge gridding The top of the McQueen Branch unit is shown affects and are extrapolations of data. on figure 14. This map is different than the underlying Middendorf in that the regional dip Top of Cape FearFormation appears to be dominantly to the southeast. Structural elevation change across the area is The surface of the Cape Fear Formation is approximately 20 meters and is represented by shown on Figure 12. Although the same map a monocline or dip reversal flexure across the edge affects are present as in the basement regional faults. Minimal effects are seen from map, the general trend of the data are similar. the MWESTA and Steed Pond Faults. More The deeper basin is to the west southwest in convoluted structure is seen associated with these data and the structural high through the the CNF and Lost Lake Faults, particularly in center of the study area associated with the the area of the greatest seismic data density in CNF and Lost Lake Fault is present. The Cape the center of the map. The gridding edge Fear is basically draped over the basement effects are great in the northern portion of this structure and has smoothed many of the minor map. structural perturbations found on the basement map by infilling. However, the formation is Top of Steel Creek Formation offset by faulting. The structural change across the area on the Cape Fear is also The top of the Steel Creek Formation is shown approximately 70 meters, suggesting that on figure 15 and is generated from borehole much of the structure is post Cape Fear in age. geophysical data. These values are the same as Basinward dip is to the west southwest. The those used in the manually contoured maps of depositional character is not obvious on this Aadland (1997). The shallower faulting on the map, although sediments primarily associated surface of the Cretaceous from Aadland with structurally lower areas east of the (1997) is shown on the maps for reference and central high are present. It is probable that this may be affecting the depositional pattern. Few area has been lowered structurally, but it is borings penetrated the Steel Creek horizon also possible that there was a trough or flow within the area and most are centrally located, passage through the area as well. therefore the edge effects on this map are

M-14 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 large. There are few regional faulting effects every 1000 meters, is strong evidence for seen in the map except for the convoluted structural control. A current dominated near structure adjacent to the CNF and Lost Lake shore sand depositional character is not Faults. Between the time of deposition of the thought be the cause of the en-echelon pattern McQueen Branch unit and Steel Creek because the features are along dip into the Formation, there was a large near shore basin and not along margin strike. marine depositional influence across the area. Thick marine sands were deposited in the Faulting and Structure upper Black Creek Formation, and a regional unconformity or disconformity at the top of The four major faults, interpreted from the the Black Creek-contact with basal Steel seismic data, are accompanied by several Creek has smoothed the surface. A regional smaller, unassigned faults. It is possible that unconformity, the possible many of the unassigned faults may be Cretaceous/Tertiary boundary global erosion correlated together and form additional fault event has further planed the Steel Creek systems, possibly those of Aadland (1997). It surface. is also probable that many of the smaller fault are basement splays from the regional faults Surface of the Lang Syne/ Sawdust Landing and that the larger faults are the primary Unconformity offsets in a complex fault system. However, it is not possible, without additional data, to The top of the Lang Syne/Sawdust Landing confirm these alignments. Many of the Formation is shown on figure 16. This map unassigned faults have significant offsets, or was also created using the same data as have complex structures, and may be Aadland (1997). The northwest to southeast important to shallower horizons, however, trending structures may be associated with additional data are required to examine this shear reactivation along the CNF and Lost possibility in detail. Lake Faults (shown on this and subsequent maps for trend information). There are The oldest fault thought to affect the A/M thickness variation in the Lang Syne/Sawdust Area is the CNF. This fault trends Landing sediments across the area that appear approximately N35E across the study area and to be related to older structure on the surface may extend an indeterminate distance to the of the Steel Creek Formation. The trend of the SSW and NNE. This fault shows reverse structural features is oblique to the strike of motion and is generally up on the SE and the regional faulting. Deformation extent may down on the NW. The amount of throw on be restricted by the bounding AMWESTA and crystalline basement varies from Steed Pond Faults. The initial timing of this approximately 30 to 35 meters maximum to oblique faulting/folding is observed in the approximately 10 meters minimum within the structural map of the Steel Creek Formation, study area. The angle of the fault is generally therefore it is assumed that the timing of the greater than 600 from horizontal. The CNF reactivation is post-Ypresian. The change in follows a propagation fold model (Cumbest structural elevation across the features is and Wyatt, 1997) and disturbs sediments approximately 12 meters as compared with through the Warley Hill Formation. It is approximately 14 to 16 meters at Steel Creek possible that horizons shallower than the time. It is not known whether the structure is Warley Hill are influenced but this is difficult accomodated by folding or faulting but the to determine from the seismic data or borehole abrupt elevation change in some areas may mapping. The correlation of CPT, GPR and suggest faulting while the less abrupt changes high resolution seismic data from Wyatt, et may suggest folding. The en-echelon, periodic al., (1997) suggests that there are near surface character of the structural events (high, low, structural influences, however, it is not clear high. low, high) occurring approximately

M-15 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 that the shallow effects are from the CNF. displacement. On many of the mapped They may possibly be from later faulting. horizons, the sense of offset varies along these faults and between faults. At the McQueen On seismic lines SRS-1 and A-5 (figures 7 and Branch Confining Unit (Figure 14) for 8 respectively), which cross the fault example, the Steed Pond and MWESTA perpendicularly, a synclinal trough is noted in Faults appear to have a left lateral offset while the footwall block. An additional sediment fill the Lost Lake may have more of a right lateral is seen in the trough suggesting that either motion. On this figure, it is possible that offset syndeposition was occurring during pre-Cape exists in the shallow horizons (up on the NE) Fear compressional faulting and that the fault splays into a positive flower (Coniacian/Turonian?, 90 mybp) or that the structure, indicative of a shear motion. CNF is a re-activated Mesozoic normal fault with a depositional remnant in the down On figure 16 the Lang Syne/Sawdust Landing warped interval associated with the NW/SE trending highs appear to truncate at extensional event (Triassic/Jurassic/early the MWESTA and Steed Pond Faults. These Cretaceous, > 90 mybp?). highs may be flexural folds associated with the differential shear motion between the A schematic of the fault propagation model MWESTA and Steed Pond Faults. The overall similar to the CNF is shown on Figure 17 sense of motions for the fault zone bounded along with an actual seismic schematic of the by the MWESTA and Steed Pond faults CNF from line SRS-1. The comparison would be right lateral. The axial crests of the between these two figures is obvious although structural highs appear to be offset by the seismic schematic does not demonstrate approximately 3000 meters from crest axis to any fore limb thickening of sediments except crest axis, which may be a predictive tool for possibly in the Lang Syne or Warley Hill location of additional highs. intervals. The lack of sediment thickening may be from the high angle of the CNF and Of the MWESTA, Steed Pond and Lost Lake unconsolidated nature of the sediments above Faults, only the Lost Lake appears to the axis. influence shallow sediments. In general, the structural influence from these faults, as The Lost Lake Fault is thought to be younger derived from the seismic data, appears to than the CNF because it apparently intersects diminish above the Middendorf horizon., and disturbs the CNF near the northern end of however, the resolution of the data do not seismic line A-3 (refer to figure 9). Because of preclude the possibility of shallow the conjugate nature of the Steed Pond and deformation. MWESTA faults to the Lost Lake Fault, they are thought to also be younger than the CNF, Assuming that structural influences have and approximately the same age as the Lost affected the topography of various Lake. These faults trend approximately N 1OE, stratigraphic horizons through time, then it and within the study area, only the Lost Lake should be possible to estimate timing and total Fault intersects the CNF. To the southwest, displacement of sediments. The effects of and beyond the study area, the MWESTA erosion are difficult to estimate. Figure 18 is a Fault may also intersect the CNF. graph of approximate maximum elevation relief, average, minimum and maximum The MWESTA, Lost Lake and Steed Pond interval thickness for the stratigraphic Faults were grouped because they generally horizons. Data were extracted from map exhibited the same relative sense of motion, figures 11 through 16 and values from the along linear trends, throughout the study area. stratigraphic picks However, the relative sense of motion may vary along these faults because of shear

M-16 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Several observations may be made from this Stratigraphy graph. The amount of structural relief on the surface of the crystalline basement is the A variety of depositional environments and greatest observed. The structural relief on the structural influences have affected the strata Cape Fear and Middendorf exceeds the within the A/M Area. In general, all sediments average and maximum sediment thickness, within the area may be characterized as near suggesting post or syndepositional structure shore marine to fluvial punctuated by dominated during the Mesozoic through submarine or subaerial erosional events. Santonian time. The minimum (and average) Within formations, the depositional character sediment thickness from the McQueen Branch may change across the area as the Confining Unit to the Middendorf (lower environment of deposition changed along Black Creek), and Steel Creek to McQueen slope. Adjacent to faults, the sediment Branch (Steel Creek and upper Black Creek), character may vary due to tectonic influences. exceeds the overall amount of structural relief The regional stratigraphy is discussed in on these horizons. This suggests that Fallaw and Price (1995), Aadland et al., depositional events predominated over (1995) and Aadland (1997). structural events during the Campanian through Maestrichtian time. For the Lang The deep borings and seismic data may be Syne/Sawdust Landing to Steel Creek interval, combined to define the lateral variability and the structural relief is greater than the character of sediments within a specific minimum sediment thickness and less than the formation. The log signatures of the average thickness. This suggests that a geophysical curves may be used to interpret combination of structural and depositional the depositional sequence or environment events have occurred during the Paleocene. relative to formation and depth, particularly From the Warley Hill to Lang Syne/Sawdust for the sand sequences (Busch and Link, 1985, Landing (Lutetian to Ypresian), the sediment and Serra, 1985). This, in turn, may be thickness exceeds the overall amount of associated with an area along a seismic line structural relief available suggesting a and further associated over a larger area. Each dominantly depositional environment. From deep Cretaceous stratigraphic horizon will be the present day land surface to the Warley Hill discussed. Tertiary strata are discussed in (Bartonian and younger), the average Aadland (1997) and this guidebook. sediment thickness is exceeded by the structural relief but the maximum sediment Cape FearFormation thickness exceeds the relief Therefore, this suggests a combination of depositional and The Cape Fear Formation varies in thickness structural events. across the A/M Area from approximately 6 meters eastward to 12 meters westward. The Based on the data from this graph, it is geophysical log signature is similar in all possible to establish the following series of penetrating borings, therefore the depositional events: 1) Paleozoic to Coniacian/Turonian: environments are thought to be similar, structural events dominant (assumed), 2) although no definitive environment may be Coniacian/Turonian to Santonian: structural interpreted from the geophysical data. In events dominant, 3) Campanian to general, and referencing the core descriptions Maestrichtian: depositional events dominant, in Wyatt et al., (1997), the formation appears 4) Paleocene: depositional and structural to be a fluvial or shoaling lag deposit with events, 5) Lutetian to Ypresian depositional interspersed sands, cobbles, pebbles, silts and events dominant, 6) Bartonian and younger, heavy minerals. Aadland (1997) contends that depositional and structural events. the Cape Fear may be missing in well P9R.

M-17 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

The geophysical logs from GCB-1, GCB-3, west portions of the study area were P8R and MMP-4-SB suggest that the shoreward during the Middendorf deposition. formation may consist of at least two and Neither the sand or clays are well developed possibly three shoaling events. Three in GCB-1, P8R or GCB-2 suggesting an distinctive lower energy intervals, punctuated environment with more of a marine influence. by sandy/silty higher energy events are noted in the GCB-1 log. In MMP-4-SB, three events The seismic data suggest that the Middendorf are also noted but have a different character, develops a more variable character to the suggesting a low energy or shoaling (possible south-southeast. Line SRS-7, an approximate heavy mineral) lag, then a higher energy dip line for Middendorf depositional time, environment, followed by another low energy shows a more variable character seaward, environment. Since structural relief exceeds while having a relatively stable "railroad depositional thickness, it is possible that the tracks" character landward or up dip. Seismic stratigraphic and depositional character of the line CNF-2, an updip strike line for Cape Fear is dominated by episodic structural Middendorf deposition also displays a events causing periodic shoaling. "railroad track" appearance while line CNF-1, further down dip, has a more variable The seismic data provide little information on character. the depositional or stratigraphic character of the Cape Fear. The seismic data does support Black Creek Formation (including the a thickening of the interval westward but in McQueen Branch Confining Unit) general, the thickness of the Cape Fear is less than the resolution of the data. Overall, the The Black Creek Formation's depositional near source, shoaling environments character and environment is similar to the interpreted for the Cape Fear are consistent Middendorf Formation except that an increase with the initial rising sea levels during the in silts and clays throughout the formation is Late Cretaceous and suggests that the A/M suggestive of a lagoonal to back bay shallow Area was near shore during this eustatic event. water and lower delta plain environments. Distinctive sand and clay units are mappable MiddendorfInterval across the area and are generally well developed to the north and east and less The Middendorf interval varies in thickness developed to the south and southwest. across the area from approximately 25 meters along a central axis to 35 meters eastward and The McQueen Branch Confining Unit westward in the area. It is possible to track (MqBCU) is a member of the Black Creek consistent members through the formation, Formation, consisting of thick clays therefore the thinned areas are apparently intercalated with thin sand/silt layers. The caused by erosion. Individual members or MqBCU approximately divides the Black beds within the formation alternate between Creek into upper and lower units. In GCB-1, 2 thinly bedded, high frequency, dominantly and 3, the MqBCU contains rich organic clays sands with interspersed clays to thinly bedded, interspersed with heavy minerals and iron high frequency, dominantly clays with staining. A greater abundance of heavy interspersed sands. The varying pattern of minerals and staining is present in GCB-3 sand units from "spikey" to "bell", "funnel" suggesting deposition further up slope. Across and "serrate" shapes all suggest a bar, bar the structural high associated with GCB-1 and finger, delta front sheet sand, depositional P9R, the MqBCU thins suggesting a structural environment. The best developed sand units influence affecting deposition. In general, the are in GCB-3, PW-1 13, MMP-4-SB and MqBCU appears to be distributed in a near MBC08ASB, suggesting that the north and shore, back barrier bay environment and may represent a sequence time line or surface

M-18 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 erosional interval between depositional cycles Steel Creek Formation of the over and underlying Black Creek. The stratigraphic character of the Steel Creek The lower Black Creek zone is generally more Formation is not discernible from the seismic clay dominated than the upper zone. Several data. From the deep borings, the formation is (generally three) clay units may be tracked fairly uniform in thickness across most of the across the lower portion of the Black Creek study area but thins in GCB-3. The GCB-3 log but are missing or thin above the GCB-1 and suggests that the upper portions of the Steel P9R high. The sand units within the lower Creek have been eroded. There are distinctive zone have log characteristics of bar-finger sand units within the formation that may be sands or delta sheet sands combined with bar locally tracked, however, they are not sands. Since the sand signatures are difficult traceable through all of the deep borings. The to track across the data, they are probably overall log character of the sand units suggests more associated with discontinuous bars a near shore bar-finger environment. rather than delta type sheet sands. Figure 11 shows the suggested depositional environments by formation. The upper Black Creek zone is sand dominated and was probably deposited in a SUMMARY higher energy environment. Individual sand units are difficult to map across the area and This study identified four principal crystalline the overall log signatures suggest bar-finger basement involved faults. The oldest regional sands and bar pinchouts. In some logs, fault trends NNE and is identified as the MBC08ASB for example, there may be a Crackerneck Fault. Three younger faults trend tidal inlet fill log signature. north. The westernmost fault is identified as the MWESTA Fault and the easternmost fault Across the A/M Area, the overall character as the Steed Pond Fault. The central fault and variation of the lower Black Creek and intersects the Crackerneck Fault and is MqBCU remains fairly constant. Further identified as the Lost Lake Fault. These faults down dip to the south and southeast (south are not thought to be single breaks in all areas and east of the Crackerneck Fault), the but linear zones of disruption. The depositional character appears to change and a intersection of the Lost Lake and Crackerneck more varied depositional pattern is seen. This Faults is a highly complex area. These faults may be the transition from upper delta, tidally are thought to be predominantly reverse faults influenced deposition to a lower delta marine with possible dip-slip, or minor strike slip influenced environment. motion. The overall pattern of the Crackerneck Fault and possibly the Lost lake The seismic character of the upper Black Fault follows a fault propagation fold model. Creek is less distinct than the lower Black The Crackerneck may be a re-activated Creek and the overall depositional pattern is Mesozoic normal fault. The overall subsurface more difficult to discern. In lines CNF-2 and structural relief within the A/M Area is SRS-7, the character is more consistent in the thought to be controlled by these faults for down dip areas to the south and southeast. strata older than the Middendorf and by a This may indicate a more stable, marine combination of sedimentation and structure influenced environment, while a higher for more recent sediments. energy, more discontinuous environment existed to the north and northwest. At least three ages of faulting are observed in the data. The oldest faulting is probably pre Cretaceous and affected deposition of the Cape Fear Formation. There may be sediments

M-19 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 pre-Cape Fear in the synclinal troughs Campbell, F. F., 1965. Fault criteria. Geophysics, associated with these older faults. The Vol. 30, No. 6, pp. 976-997. majority of faults are post-Cretaceous in age Cumbest, R. J. and D. E. Wyatt, 1997. Fault-bend and disrupt the entire Cretaceous sediment folding in unconsolidated Coastal Plain sediments column. At least two pulses of post and possible effects on hydrologic and contaminant transport properties. Geological Society of America Cretaceous movement are noted. A more Abstracts with Programs, Southeastern Section, V. recent structural event is seen in the Paleocene 29(3), p. 44. and younger sediments. This event may be a re-activation of the deeper faulting in a strike Fallaw, W.C., and V. Price, 1995. Stratigraphy of slip mode. These younger structures trend to the Savannah River Site and Vicinity, Southeastern the NW and occur in an en-echelon pattern. Geology. Vol. 35, No. 1, p. 21-58. This pattern may affect strata to near surface or surface horizons. Faye, R. E., and D. C. Prowell, 1982. Effects of Late Cretaceous and Cenozoic Faulting on the Geology and Hydrology The stratigraphic information for the deeper of the Coastal Plain Near the Savannah River, Georgia, and South Carolina. horizons is limited due to the limited number U.S. Geological Survey. Open File Report 82-156. of deep geophysical logs tied to the seismic information. However, a comparison of Pascal, R., and R.W. Krantz, 1991. Experiments on regional deep logs allows for a discussion of Fault Reactivation in Strike-Slip Mode, possible deep stratigraphy. In general, all Tectonophysics. 188:117-131. sediments were deposited in a near shore, marine to fluvial environment and vary from a Prowell, D. C, 1994. Preliminary geologic map of tidally dominated to a wave dominated the Savannah River Site, Aiken, Allendale, and depositional character. For all Cretaceous Barnwell counties, South Carolina. USGS OFR 94 181. 11 p. strata, there is a noticeable change in depositional character south and southeast of Reineck, H. E. and I. B. Singh, 1980. Depositional the Crackerneck Fault from a near shore to sedimentary environments, 2nd ed. Springer more distal environment. Overall, there is a Verlag, New York, 549 p. general thickening of Cretaceous strata to the southeast and south. Figure 19 provides a Serra, 0., 1985. Sedimentary Environments from depositional relationship of the various Wireline Logs, Schlumberger Educational Services, stratigraphic units underlying the A/M Area to Houston, 211 p. a deltaic, near shore model. Sheriff, R. E., 1982. Structural interpretation of seismic data, Education Course Series #23, AAPG, REFERENCES Tulsa, 73 p. Stephenson, D. and A. Stieve, 1992. Structural Aadland, R. K., 1997. Tertiary Geology of A/M model of the basement in the Central Savannah Area Savannah River Site, South Carolina (U). River Area, South Carolina and Georgia (U), WSRC-RP-97-0505, Rev 1., 62 p. WSRC-TR-92-120, 43 p.

Aadland, R.K., J. A. Gellici, and P.A. Thayer, Wyatt, D. E., R. J. Cumbest, R. K. Aadland, F. H. 1995. Hydrogeologic Framework of West-Central Syms, D. E. Stephenson, J. C. Sherrill, 1997. South Carolina. State of South Carolina Investigation on the Combined Use of Ground Department of Natural Resources, Water Resources Penetrating Radar, Cone Penetrometer and High Division. Report 5. Resolution Seismic Data for Near Surface and Vadose Zone Characterization in the A/M Area of Busch, D. A. and D. A. Link, 1985. Exploration the Savannah River Site, WSRC-RP-97-0184 Methods for Sandstone Reservoirs, OGCI Publications, Tulsa, 327 p.

M-20 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Wyatt, D. E., R. J. Cumbest, R. K. Aadland, F. H. Syms, D. E. Stephenson, J. C. Sherrill, 1997. Interpretation of Geological Correlation Borings 1, 2, 3 in the A/M Area of the Savannah River Site WSRC-RP-97-0185

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

- 36ý0000

oSl

Figure 1. General study area. Colors represent the surface exposure of various geological formations. 'Tu' is the Upland unit, 'Ttr' is the Tobacco Road Formation. 'Tdb' is the Dry Branch Formation. 'Tm' is the McBean Formation. 'Qall' and 'Qal2' represent Quaternary alluvial fill material, with the numbers representing relative ages of deposition. Grid coordinates are in UTM. Roads are noted as thin black lines. The heavy black line defines the area of data used for this study. Geology is from Prowell (1994). CýO t

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

::TýM

Figure 2. Location of seismic lines and deep correlation wells and borings used in the study. Red lines are the seismic lines and the well or boring locations are labeled. Data are superimposed on surface geology (from Figure 1).

0A~

M 23 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

(Fallaw and Price, 1995) Lithostratigraphic Units Hydrostratigraphic Units

Fori Nomenclature Period/Epocl Grmations- 0 Upper Three Runs Barnwell Aquifer Group Floridan 100" Steed Pond Aquifer Eocene System Aquifer ~-~Z~ordonConfining Ur a Orangeburg Z-7 Group 200 a -Conogare.eEOMIsttolL Gordon Aquifer I- .. F ourmnile-FD on..atiof.- a2 0) Black -Snapp'EormaionD-- 0_ Mingo Lang Syne/ E Crouch Branch Meyers 0 Paleocene Group Branch - 300 Sawdust Landing Confining Unit Confining 0 U) 2 LL System a 0U C Steel Creek <0 0 €-400 Formation Dublin 76 0) co Crouch Branch Aquifer Aquifer a System "a aL 0 .9 500 Allendale x Black Creek Confining 0•1) 5<0 ca. 0. :3 Formation McQueen Branch Confining Unit System CL 0 2 o a• 0~ Ci 600- a. a ru 0C-) Midville E Aquifer 09 Middendorf McQueen Branch Aquifer ... System (- 700-- Formation

Fear "Appleton Cape Confining 0: 8001 Formation 0c Undifferentiated System "0-

900 Paleozoic Crystalline Basement Piedmont Hydrogeologic Province or Triassic Newark Supergroup

Figure 3. Stratigraphic chart representing the sediments within the A/M Study Area. Data are from Aadland et al., (1995).

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

U A sIlls Rao0 sity GeOCJistn.I Gamma Spectral 00(0 AI4 1 Erwironments lIntereted Age a '+sd ISO of O)eposetion 0 U '0 Contacts 0 OR ,63654 iso 56l

Pnaboniai, shIt r~noshs

C.Me 111f 1 1 J I- F SI-~ ., II±HJ± 0) Lq~eian sha A us Srff S 0)

0262tdsI aM -In"ofl

I -- I Id0 56rd ypresian 6 I -'Sn IU14 '6 !566 I •nminedrac Theistn. sh5 555 t F I 's hOfa 10ln[5t 6 Uný dsI dIOIbLflay •H Dai'. *3j0 bss. sM bsr C)

,sagnsl ha. flogs, taM, and It R1 dsj, Itss 4 in Tsp0141k V'4*5 to.t MHU ...... M

______s ri ooljt 'JIM 2 02 02

-_1 17 1nd 4h5~

0i

0

156' 4005 0556462 6* d'40. 4 C62i4w n,. ; MR P62stp. 00 'vs athrM 014 -o traur0d 0) cli Io.1'e sclist. 0 pn65,5s 5151514 motavoIon.os. A 41., 00.1664 frOctura6j 62 '0* Tiff" GCB-1

Figure 4a. Combined interpretation of GCB-1. Stratigraphic picks are from the correlation of GCB-1,2 and 3 to regional horizons. Depositional environments are interpreted from the geophysical log signatures, field core descriptions and core laboratory data. Hydrostratigraphy is from Aadiand et al., (1995). Stratigraphy and chronostratigraphy are from Aadland et a]. (1995), Fallaw and Price, (1995) and DNAG, 1983. Palynology is from Christopher (personal communication).

M-25 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-200000606

GCB-I GCB-2 GCB-3 mst

o Surface TO WH

Top Congae Steed Pond Aquifer

Top LS/SL CBCu 'C"sand

Top BC Crouch Branch Aquifer

MqBCU

McQueen Branch Aquifer

5w Top Mid

eo Top CF Pzm/Sap Acoustc Basement

700

Figure 4b. GCB-1, 2 and 3 correlation panel. Datum is set to 330' (110 m) nis]. Depths are in feet. Color of correlation lines correspond to color of horizon name. "Top WHI is the top of the Warley Hill Formation. "GCCZ" is the Green Clay Confining Zone. "Top LS/SL" if the top of the Lang Syne/Sawdust Landing Formations. "CBCU" is the Crouch Branch Confining Unit. "Top BC" is the top of the Black Creek Formation. "MqBCU" is the McQueen Branch Confining Unit. "Top Mid" is the top of the Middendorf Formation. "Top CF" is the top of the Cape Fear Formation. "Pzm/Sap" is the contact with the weathered basement rocks or saprolite. Acoustic Basement is the velocity crossover from coastal plain seismic velocities to those more typical of crystalline rocks.

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

() %GPaL

V2)fli 0ret ( CalpER D D 0oa 2'0l0 S I5 rr DENSITY (In)onr.al M PS4S CNar P170 0 200' .0 t•4 o •DO 0.05- C itL U 0.10 I,,"

i-~ C

125 -4- rpmssw4

Figure 5. Synthetic seismogram and tie to seismic data. Sonic and density data from GCB-I were used to calculate the synthetic seismogram. Traces from seismic lines A-5 and CNF-1, adjacent to GCB I, were used for correlation. The synthetic data have been phase shifted by 3000. Key stratigraphic horizons, identifiable on the seismic data, have been defined.

M 27 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

i

Figure 6. Deep borehole correlation panel flattened on a 30 foot datum relative to mean sea level. Key stratigraphic horizons are labeled. Natural gamma, spectral gamma and/or calculated gamma ray curves are shown. CCQ M-28 -u

Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

125.00 133.00 141.00 14 (I )Nari. al %SAND KB ]Dtbt h

Feet

200

400

600

800

1000

1200

Figure 7. Synthetic seismogram from GCB-I plotted against seismic line SRS-1 and core data adjacent to the Crackerneck Fault. (0-7

M-29 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

so 400

Figure 8. A portion of seismic line A-5, shown as representative of the seismic data distribution shown in Figure 9.

c3 ,

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

4

A

4 1)"

1>4 /

/ I

Figure 9. Distribution of seismic data interpreted for this paper. Seismic lines SRS-1, SRS-7, and SRS-12 are regional lines acquired in 1987. Lines CNF-1 and CNF-2 were obtained to help map the Crackerneck Fault system for regional implications and are high resolution data. Lines A-1 through A-5 were obtained to aid in mapping the subsurface associated with the M-Area plume remediation efforts and are also high resolution data. Line MCB-1 was acquired to evaluate the shallow structure and stratigraphy associated with the Miscellaneous Chemical Basin waste unit and to evaluate the use of very high resolution acquisition with a vibroseis source. The shaded colors correspond with calculated depth to crystalline basement, darker colors (blues ) are shallower and lighter colors (reds) are deeper. The pink lines crossing the seismic data are the projections of the faults.

M-31 ýoq Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

260 ars. (upper Middendorf 310 ins. (basal Cape Fear)

270 res. (inddle MiddendorO 320 a*s(approximate top of saprolite)

2. 60 50 50 * !ý 40

300 ins. (approximate top of Cape Fear) 325 ins. (approximate top of crystalline rock)

Figure 10. Three dimensional seismic data. Time slices are shown as labeled. Red colors are area of higher amplitude, and blues are lower amplitude. Amplitude changes across the figure suggest either structural or stratigraphic variations.

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Figure I1. Subsurface map on top of the crystalline basement "rock" as determined from the seismic data and the deep borings. Elevation are in meters relative to mean sea level. The grid is in ULM coordinates. SRS roads are shown for location. The pattern of seismic data is shown by thick black lines (numbered with shotpoints where data has been interpreted). The Crackerneck Fault is shown as a north trending solid thin black line, the MWESTA, Lost Lake and Steed Pond Faults are shown as NNE trending dashed lines. Faults interpreted from the deepest stratigraphic investigation of Aadlaud (1997) are shown as dotted lines. 0, j(

M-33 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

-H I

Figure 12. Subsurface map on top of the Cape Fear Formation as determined from the seismic data and the deep borings.

C (ýý M-34 -]

Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Figure 13. Subsurface map on top of the Middendorf horizon as determined from the seismic data and the deep borings.

M 35 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Figure 14. Subsurface map on top of the MeQueen Branch Confining Unit as determined from the seismic data and unit penetrating borings.

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

- I j I

Figure 15. Subsurface map on top of the Steel Creek Formation as determined from the seismic data and unit penetrating borings. C46 M-37 l

Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

I MIKA-

Figure 16. Subsurface map on top of the Lang Syne/Sawdust Landing unconformity as determined from the seismic data and unit penetrating borings.

OIQ M-38 -7

Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Foot Wall Syncline Ls-.JI Hanging Wall Anticline

"-4t--400m. -,

WH

LSSDL

MqOCU

CF - -ok

NW

Figure 17. Top figure is fault propagation folding over a reverse fault. (Modified after Cumbest and Wyatt, 1997). The lower figure is the actual seismic horizon schematic from line SRS-I over the CNF. The horizons are labeled as; "rock" is crystalline basement, "CF" is the Cape Fear Fro,, "Midd." is the Middendorf Fm., "MqBCU" is the McQueen Branch Confining Unit, "LS/SL" is the Lang Syne/Sawdust Landing Fro., and "WII" is the Warley Hill Fm. The offset in basement rock is approximately 30-35 m. The distance from the anticline axis to the syncline axis is approximately 400 meters. c/-- M-39 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

140

120 ]

100

80 160

40

20

0 rock CF Midd. McQBCU SC LSiSL VA- Surface

Streligraphie Horizon

Figure 18. Graph of structural relief, average, maximum and minimum sediment thickness for the mapped stratigraphie horizons. "CF is Cape Fear, "Midd' is Middendorf, "McQBCU" is McQueen Branch Confining Unit, "SC" is Steel Creek, "LS/SL" is Lang Syne/Sawdust Landing, "WH" is Warley Hill.

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Figure 19. Environments of deposition anticipated within the A/M Area. Figure is modified from Aadland (1997). Stratigraphic units, with the anticipated environments of deposition within the A/M Area are shown in red. eL{9

M-41 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Notes

M-42 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Use of Seismic Reflection Amplitude Versus Offset (AVO) Techniques to Image Dense Nonaqueous Phase Liquids (DNAPL) at the M-Area Seepage Basin, Savannah River Site, South Carolina

M. G. Waddell, W. J. Domoracki, T. J. Temples, Earth Sciences and Resources Institute, University of South Carolina, Columbia, SC 29208

ABSTRACT and amplitude of acoustic waves reflected from subsurface. The section can reveal faults, burial One of the most difficult problems in designing channels, and subsurface lows that might a remediation plan for cleaning up DNAPL influence the migration of DNAPL in the contamination is locating the pools of free-phase subsurface. DNAPL. The seismic modeling of a DNAPL saturated sand versus a water saturated sand The amplitude and arrival time of seismic waves suggests that with frequencies of 120 Hz or is dependent on the elastic parameters of the higher there would be an amplitude versus offset subsurface including bulk modulus, shear (AVO) anomaly. Seismic survey acquisition modulus, density, Poisson ration, and angle of parameters for imaging the DNAPL were the incidence of the impinging energy. The last derived from an AVO model, which was based two parameters can, in certain instances, be used upon previously acquired seismic and well data. to infer the fluid content within the pore spaces. The seismic line was located in such a manner In the Petroleum industry seismic amplitude that it started in an area where the versus offset (AVO) methods are used to directly unconsolidated sand was water saturated and detect hydrocarbon bearing strata. In this study crossed a known pool of free-phase DNAPL we adapt some of these techniques to directly saturated sand and continued back into a water detect the presence of DNAPLs at the United saturated sand. Using a weighted stack States of Department of Energy Savannah River processing technique (Smith and Gidlow, 1987) Site (Waddell and Domoracki, 1997). If these a "fluid factor" stack indicated an anomaly at the techniques can be found to be applicable to other depth and location of the known free-phase sites, remediation of DNAPLs can be facilitated DNAPL plume. The initial results suggest that and be achieved at lower cost. under certain conditions free-phase DNAPL can be imaged using high-resolution seismic Savannah River Site reflection techniques. The Savannah River Site (SRS) is located in INTRODUCTION South Carolina on the South Carolina- Georgia border. During the Cold War SRS was a major Imperative to any DNAPL remediation effort is production facility of nuclear materials for the ability to locate high concentrations of defense purposes. Since the late 1980's an contaminants. Traditional techniques such as emphasis on environmental restoration has led to borehole sampling run the risk of cross the development of programs and strategies to contamination of aquifers. In addition, high remediate DNAPL spill at the site. One area of concentrations of DNAPL can be missed SRS targeted for remediation is the M-Area because of inadequate spatial sampling. Seismic seepage basin. reflection profiling is a geophysical technique that can be conducted to yield horizontal The M-Area seepage basin was constructed in measurements every foot and vertical 1958 to contain uranium wastes and residual measurements every 3-5 feet depending on the solvents produced from reactor fuel and target survey design. The principal data collected from degreasing operations (Fig. 1). An estimated a seismic reflection survey are the arrival time two million pounds of residual solvents were

N-1 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 released into the eight million gallon unlined METHODOLOGY surface impoundment over a period of nearly thirty years. In 1988 the basin was closed, The approach taken was thee fold consisting of backfilled, and covered with an impermeable 1) evaluation of existing geological and cap. Chlorinated solvents, including free-phase geophysical data concerning the amount and constituents, have been detected in the distribution of DNAPL, 2) seismic modeling to groundwater near the seepage basin since 198 1. determine whether or not an AVO anomaly The majority of the DNAPL found in the would be expected from DNAPL saturated subsurface is composed of Trichloroethylene sediments, 3) acquisition and processing of a (TCE), Tetrachloroethylene (PCE), and seismic line designed specially to image the Trichloroethane (TCA) (Looney, 1992). DNAPL. Environmental remediation strategies have included groundwater pump and treat, soil vapor extraction, in situ air stripping, and in situ biomediation.

The near-surface geology at the M-Area seepage basin is comprised of Eocene age Upper Coastal Plain sedimentary units. On the surface is the "Upland unit" which consists of cobbles and coarse sand ranging in thickness from zero to fifty feet. Underlying the "Upland unit" are the Tobacco Road and Dry Branch formations which are composed of fine to medium grain sand, clayey sand, and discontinuous layers of clay. The amount of clay in the formations decreases with depth. Directly below the Dry Branch Figure 1. Location map of all the 2-D seismic lines acquired for AVO analysis. Well MSB-3 Formation is the Warley Hill Formation ranges in thickness from 0 to 10 feet and occurs at a is adjacent to well MSB-22. depth of approximately 155 feet below the surface. This clay, when present, is considered Seismic Amplitude Techniques the confining unit which separates the overlying surficial aquifer from the semi- to confined In the 1960's petroleum companies recognized aquifer below. The DNAPL in the M-Area that in young sediments (Tertiary age) large pools on top of the "green clay". seismic amplitudes were associated with gas saturated sands. However, it was soon realized OBJECTIVES that not all large seismic amplitudes represented hydrocarbon saturated sands. The normal The primary objective of this study was to test incidence (NI) reflectivity (bright spot) the feasibility of using high-resolution seismic techniques involved three different scenarios techniques and direct hydrocarbon indicator based upon a water saturated state and a analyses to image free-phase and dissolved phase hydrocarbon saturated state (for this discussion DNAPLs at the M-Area seepage basin. Other a sand/shale or sand/clay interface). The objectives were to use the seismic data to map scenarios are classified by changes in NI the subsurface geology and to determine the reflectivity from a water saturated sand to a gas geologic controls on the distribution of the or hydrocarbon bearing sand. DNAPL. The three scenarios are:

0 Dim-spot- a large positive amplitude that

N-2 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

is reduced to a smaller positive amplitude, waves reflected at a boundary between two elastic media. Koefoed observed that if there "* Phase reversal- a small positive amplitude were two elastic media with the top medium that changes to small negative amplitude and having a smaller Poisson's ratio than the underlying medium there would be an increase "* Bright spot- a negative amplitude increasing in the reflection coefficient with increasing angle to a large negative amplitude. of incidence. He also observed that if Poisson's ratio of the lower medium was lower than the The dim-spot is generally associated with a overlying medium, the opposite would occur large acoustic impedance contrast and is a with a decrease in the reflection coefficient with technique for inferring lithology. Bright spot an increase in the angle of incidence. Another anomalies are generally used for interpreting observation showed that the relative change in lithology and estimating sand thickness. Phase reflection coefficient increases as the velocity reversal reflections are not generally reliable contrast between two media decreases. Koefoed because geologic features (e.g. faults) can cause also observed that if Poisson's ratio for two the reflections to appear to reverse phase. Thus, media was increased, but kept equal, the a reflection phase reversal does not necessarily reflection coefficient at the larger angles of indicate a change in lithology (Verm and incidence would also increase. Ostrander (1984) Hilterman, 1995). The bright spot technique was observed that changes in Poisson's ratio caused the first direct hydrocarbon indicator. by the presence of hydrocarbons in the pore space has dramatic effect on the P wave In 1984 Ostrander published a article entitled reflection coefficients and that these effects can "Plane-wave reflection coefficients for gas sands be related to seismic amplitude anomalies. at non-normal angles of incidence." Ostrander observed that the P wave reflection coefficient at In order to understand amplitude versus offset the interface between two media varies with the (AVO) analysis, one has to understand offset angle of incidence of the impinging energy. dependent reflectivity. Offset dependent Ostrander also investigated the phenomenon of reflectivity is defined as the variation of the compressional wave reflection amplitude reflection and transmission coefficients with variation with angle of incidence and changes in changing of the incident angle (Castagna and Poisson's ratio. Poisson's ratio is defined as the Backus, 1993). The offset refers to source to ratio of transverse strain to longitudinal strain receiver separation. Increasing source to and can be expressed in terms of P wave and S receiver separation results in increasing angle of wave velocity (Sheriff, 1991): incidence for raypaths as measured from the normal to a horizontal interface. Coincident 2 source and receiver locations results in what is v termed normal incidence, i.e. vertical P -2 transmission and reflection from a horizontal V (1) interface. The amplitude of the reflected and transmitted waves are described by the reflection (~[ V] Ij and transmission coefficients. The following discussion describes the equations and theory used to determine amplitude for both the (Y = Poisson's ratio reflected and transmitted waves at an acoustic Vp= compressional wave velocity boundary for normal incident energy and non Vs= shear wave velocity normal incident energy, i.e. offset dependent reflectivity. Note that this discussion is for a Much of Ostrander's work was based upon simplistic model of a single interface. The Koefoed's 1955 work on determining the majority of reflections observed on a seismic reflection coefficients of plane longitudinal profile are the superposition of events from

N-3 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 multiple layers and has a more complex AVO generates four wave types: reflected P, response. reflected S, transmitted P, and transmitted S. Snell's law from optics governs the angles of As implemented in the Petroleum industry, AVO reflection and refraction. The P wave analysis involves comparing modeled AVO velocity, density, and Poisson's ratio describe responses with field data to find a deviation from the material properties of the media. The S an expected background response. The expected wave velocity can be found from the P wave background response is usually taken to be a velocity and Poisson's ratio. water saturated reservoir; hence, the deviation from the expected response is an indication of Snell's Law, hydrocarbon presence but does not indicate sin 0, sin O_. sin 0, sin 0, (2) quantity. DNAPLs have the same acoustic p= Vp, /p: Vs, VY, characteristics as liquid hydrocarbons; therefore, if DNAPL is present in free-phase and in large enough quantities, similar types of analyzes as Vpj = P wave velocity in medium 1, Vp P wave velocity in medium those performed for the petroleum industry can 2 = 2, Vs = S wave velocity in medium be applied to directly detect the presence of 1 1, V, = S wave velocity in medium DNAPL. 2 2, 01 = incident P wave angle, An understanding of reflection AVO techniques 02 = transmitted P wave angle, can be obtained by a review of elastic wave (p, = reflected S wave angle, propagation. A P wave incident on a boundary (P2 = transmitted S wave angle, and between two linear elastic homogeneous p is the ray parameter. isotropic (LEHI) media generates four types of The reflection coefficient of the P wave as a waves: 1) transmitted P wave, 2) reflected P function of the incident angle, Rp (0), is defined wave, 3) reflected S wave, 4) a transmitted S as the ratio of the amplitude of the reflected P wave (Figure 3). The amplitudes of the reflected wave to that of the incident P wave (Castagna and transmitted waves at the boundary depend and Backus, 1993). The P wave transmission upon the P wave and S wave velocities. The coefficient, Tp (0), is the ratio of the amplitude density of the two media and the angles of of the transmitted P wave to that of the incident incidence and refraction, are determined from P wave (Castagna and Backus, 1993). The P Snell's Law. wave reflection coefficient, Rp ,at normal incidence is given by the following equation: Reflected Incdnt S-Wave P-Wave Rps Reflected P (3) WdZe R, I In I,,+j, 2 ,,, 2 If Medium 1 VpIN M , 1 1 01

Interface 'p2 acoustic impedance of medium 2 p 2 Vp2 of medium 2 02 P2 density Tnranmitted p,1 acoustic impedance of medium I pIVpI Medium 2 v2' Vý'P2 ý2 PmWave" p= density of medium I Ipa = average acoustic impedance across the interface 2 = (Ip2+lpl)/ , and Transmitted S-Wave Alp = Ip-lpl.p

The P-wave transmission coefficient at normal Figure 2. Elastic waves generated at a incidence T. is given by: boundary. A P wave incident at an angle 0 on a boundary between two liner elastic Tp = 1-Rp. (4) homogenous isotopic (LEHI) materials The variation of the reflection and transmission

N-4 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 coefficients with incident angle and source to receiver offset is referred to as offset dependent AV, = (V,2 - Vp1 ) 0 =(02 + 01)/2 reflectivity (Castagna and Backus, 1993). The values of the reflection and transmission AmT= (G2 -+- (1) coefficients for non-normal angles of incidence y = (G2 + o1)/ 2 are given by the Zoeppritz (1919) equations. The AV,= (Vs2- Vsl) complexity of the Zoeppritz equations has led to numerous approximations to simplify the Vs= Vs + Vs]) / 2 calculations. Some of the approximations are ( 2 Bortfield (1961), Aki and Richards (1980), and Shuey 1985. The Aki and Richards (1980) Ap = ( P2 - P) P=( P2+Pl )/2 approximation to the Zoeppritz equations is given below: 1 Aci R-I -VP P A= Ao( 2() 2 VPpP (Iag) Ro Ag) R(0)-a ( AV)+b ( )+c ( (5) VP P Vs A v,p B) ( ( 1-2or ) Ao B-2 (0+ VP 0 = arcsin [ (Vp2 /Vp ) sifOincide,,t] I-(T B A v, + Ap 2 Ap a = V2 + tan 0 Vp b= 0.5-[(2Vs2 / V, 2 ) sin 20] Vp,= P wave velocity of layer one c = -( 4Vs2 / Vp2 ) sin 20 Vp = (Vpl + Vp2 )/2; VP is P warave velocity Vp2= P wave velocity of layer two V, = S wave velocity of layer one VS= (Vl + V2 )/2; V, is S w'ave velocity 1 V,2= S wave velocity of layer two P = (PP+ p, ) / 2 ; p is bulk density p- = density of layer one AVp = Vp2 - Vp 1 P2 = density of layer two AVs = Vs - Vs 2 1 a,= Poisson ratio of layer one Ap = P2- PI G2 = Poisson ratio of layer two 01 = incidence and transmission angle layer one. In this equation the reflection amplitudt 02 = incidence and transmission angle layer two. expressed in three terms containing P w Ro= Normal incidence (NI), i.e. reflection velocity, S wave velocity, and bulk density. coefficient for zero-offset. B = is the AVO gradient. The Aki and Richards approximation (Equa Ao= is the normal incidence amplitude. 5) was rearranged by Shuey (1995) to obta more convenient form. The Sh The approximation above can be simplified approximation of the Zoeppritz equati further. If the average Poisson's ratio is assumed stresses the importance of Poisson's ratio as to be 1/3 and higher order terms that are primary determinant of the AVO response, insignificant above 30" are dropped, the formula reflection (Allen and Peddy, 1993). In this st for the angle dependent reflection coefficient we used the Shuey approximation, wt becomes: expresses angle dependent reflectivity in te of P wave velocity, bulk density, and Poiss( 9 ratio to compute the AVO models. R(O) = NI+( -Au - NI) sin 20 (7) 4 The Shuey (1985) formula for the refleci 2 coefficient (amplitude) is: NI+Bsin 0 (8)

R(O) = NIcos 2 0 + PRsin 20 (9) (6) NI and PR are defined as

R(O) R+(A°*(2) RO+ *sin20 + * 7*tan 20-sin 2

N-5 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

(10) (V *P I ; p') (Z._ .GB I) 7z is the acoustic impedance: (Table 1). NV I P)-(+ ' p) ( Iz- Using the parameters in Table 1, the results of the modeling suggested that there would be an PR 2 (11) AVO effect caused by the presence of DNAPL (i-a-y ) (Figures 3,4, 5). Furthermore, these results indicated that changes in the reflection (Verm and Hilterman, 1995). Reflection AVO coefficient would begin to occur at can be thought of a combination of normal approximately 220 angle of incidence. Using this incidence reflectivity and a far offset reflectivity, information the seismic lines were designed such or "Poisson reflectivity," that arises primarily as that half the receivers would be under this a result of changes in the Poisson's ratio between incident angle and half would be over. media. The second type of model was generated using To implement AVO analysis, the NI and PR the P wave, S wave, and density from an existing coefficients are extracted from a common depth well. For this type of modeling a synthetic CDP point (CDP) gather. Initially the CDP gather is gather was generating using the velocity and transformed from a function of offset to incident density data from the well is shown in Figure 6 angle. This transformation requires knowledge (left). To investigate the AVO response caused of the root mean square (RMS) velocity, which by the presence of DNAPL a ten foot interval of is ideally obtained from borehole sonic logs. In the logs corresponding to the depth where the the absence of sonic logs a rough estimate of the DNAPL is accumulating was replaced with the RMS velocity can be obtained from the normal same velocity and density parameters for TCE moveout (NMO) stacking velocities. Next, the used to generate the models shown in Figure 3, NI and PR coefficients are found by fitting either 4, and 5. Also, the model was convolved with a Equation (8) or (9) to the amplitudes. 120 Hz Ricker wavelet to simulate typical high resolution seismic data. Figure 6 (right) is the Modeling modeled CDP gather for a TCE contaminated sand layer. The most important aspect to this study is the AVO modeling, which was used to design the Comparison between the synthetic CDP gather field acquisition parameters for seismic profiles models demonstrates that, in this case, an AVO M-l, M-2, and M-3. The first type of model was effect can be expected due to the presence of generated using the Aki-Richards (1980) and TCE. This AVO effect is manifested as a large Smith and Gidlow (1987) approximations to the increase in amplitude with increasing shot to Zoeppritz equations. The model is a sand wedge receiver offset. The increase in amplitude is saturated with either water or TCE overlying much larger than if no TCE were present either a clay layer or a water saturated sand TABLE 1. Parameters Used to Generate AVO Models

Lithology VP V, Density ft/s ft/s g/cc Wedge Water Sand 5800 1450 1.9 TCE Sand 4968 1634 2.07 Substrate Clay 5600 1300 1.85 Water Sand 5600 1460 1.89

N-6 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

0.5

t3)t4 C

0 C 0

9I-C

-0.5 1 0 20 40 60. 80 Incident AngIe

Figure 3. Graph of reflection coefficient versus angle of incidence using the Aki-Richards (solid line) and Smith and Gidlow (dashed line) approximations to the Zoeppritz equations for water saturated sand overlying the "green clay". At the sand/clay interface the reflection coefficient is slightly negative and becomes more negative with increasing angle of incidence. At large angles of incidence (greater than 500) this effect is pronounced.

0.5 -I

A Si-Richards C

(2 0 C Smith and Gidlow

OD

4 W' 0

-0.5 0 20 40 60 80 incident Angle

Figure 4. Graph of reflection coefficient versus angle of incidence using the Aki-Richards (solid line) and Smith and Gidlow (dashed line) approximations to the Zoeppritz equations for TCE saturated sand overlying the "green clay". In this scenario, the amplitude is slightly negative, but at 22' the reflection coefficient goes from slightly negative to positive and increases with angle of incidence.

N-7 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

0.5

4

S0

COAk-Rchards

.4

-0.5 0 20 40 60 80

Inci dent Angle

Figure 5. Graph of reflection coefficient versus angle of incidence using the Aki-Richards (solid line) and Smith and Gidlow (dashed line) approximations to the Zoeppritz equations for water saturated sand overlying TCE saturated sand. The reflection coefficient at 0 angle of incidence is near 0'°, or is slightly negative, and at 220 becomes increasingly negative.

Time Time CDP flf CDP (ins) 0ff 68 134 210 68 134 210 0ff (ins)

1 20 40 140

Figure 6. Synthetic CDP gather generated using P wave and S wave velocity logs from well MHM-21 and a density log from nearby well MHT-1. Notice that the reflection at 120 ms has a slight increase in amplitude with increasing offset. The synthetic seismogram on the right is the same as on the left, but the P wave, S wave, and density values have been replaced using the parameters as in Figures 4-5 to simulate a 10 foot section of TCE satuatued sediment. Notice that the reflection at 120 ms has a much greater increase in amplitude with offset as a consequence of the presence of TCE.

N-8 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Seismic Data Acquisition weight drop sources. None of these sources were able to combine the requirements of adequate The original project consisted of recording one signal penetration, high frequency content, and seismic profile, line M-1, across a known minimal source generated noise. Lastly, a 10 lb. DNAPL plume that has a free-phase component Sledgehammer was tested. The sledgehammer (Fig. 1). However, after processing M-1 and was found to be a repeatable high frequency preliminary AVO analysis (fluid factor stack) source that generated a relatively small surface was preformed, an AVO anomaly was detected wave. at the location and depth of the known DNAPL plume. As a result, it was decided to acquire two The acquisition parameters for seismic line M- I additional lines M-2, and M-3 and a vertical appear in Table 2. The parameters such as group seismic profile (VSP) at well MSB-9A (Fig. 1). spacing , near offset, and far offset, were based upon the modeling results. The target interval All of the data were collected with a 24 bit OYO was the "green clay" aquitard at approximately DAS- 1 seismograph recording either 48 channels 155 feet depth. The recording offsets were (M-1) or 96 channels (M-2 and M-3). The M chosen in such a way as to have at least 15 to 20 Area is a notorious low signal-to-noise seismic geophone groups under 220 angle of incidence so data area. Two test lines were shot prior to the that the AVO analysis described above could be acquisition of the M-series lines using mini preformed on the seismic lines. vibrator, downhole Seisguntm, and EWG-1

TABLE 2. Acquisition Parameters for Seismic Line M-1

Number of Channels 48 Group interval 2ft. Shot interval 2 ft. Near offset 20 ft. Far offset 114 ft. Nominal CDP fold 24 Geophone frequency 40 Hz Energy source Hammer /8 hits Sample rate 0.25ms Record length 500 ms

After line M-1 was processed, modifications Seismic Data Processing were made to the basic recording parameters for acquisition of lines M-2 and M-3. For those The seismic data were processed with standard lines, a 96 channel recording system was used CDP data processing sequence (Yilmaz, 1987) which allowed a greater range of offsets to be that included frequency-wave number filtering recorded. For lines M-2 and M-3 the minimum (F-K or pie slice filtering) to eliminate linear and maximum offsets were 29 and 219 feet noise trains, spiking deconvolution, and iterative respectively. velocity analysis and residual statics application. For display, the data were filtered to a 90-275 Hz passband and five point running mean was

N-9 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 applied to enhance the lateral continuity of residual reflections should denote sediments reflections. To analyze AVO variations, near saturated with fluids other than water. In this and far offset stacks were generated as well as project, DNAPL would be the only fluid other Smith and Gidlow (1997) fluid factor stack. than water to saturate or partially saturate the sediments. DIRECT DETECTION OF DNAPL Profile M-I Offset Range Limited Stack At the M-Area seepage basin two primary types of DNAPL are present below the water table, In Figure 7 the upper profile is a near offset trichloroethylene (TCE) and tetrachloroethylene stack and the middle profile is a far offset stack. (PCE). The latter being the predominate type of If there are any AVO anomalies, they should be solvent. Water samples taken from well MSB present on the far offset stack and absent on the 3D (Fig. 1) consisted of a separate phase liquid near offset stack. At shot point (SP) 79 at about composed of PCE with a subordinate amount of 89 ms is an anomaly that was drilled ( well TCE (Looney, 1992). MOX-6) and TCE was found to be present. On the near offset stack the anomaly is absent. In this project two methods were used to Another anomaly is shot point 297 at about 109 investigate any AVO effects caused by the ms. This anomaly is adjacent to well MSB-3 presence of DNAPL. As previously mentioned, which had free phase DNAPL. Another the recording geometry was such that 15 to 20 anomaly is at shot point 430 at about 110 ms geophone groups were under 220 angle of which is believed to be DNAPL, but is as yet incidence. If the models were correct, there untested. would not be any significant change in amplitude under 220 . Method one was ranged limited Profile M-1 Smith-Gidlow (Fluid Factor) stacking. In this method data were gathered and Stack stacked using subsets of the range of offsets to produce a near offset section (Fig. 7 top) and far Contained in Figure 7 (bottom) is a fluid factor offset section (Fig. 7 middle). AVO anomalies stack based upon the Smith and Gidlow (1987) produce by the presence of DNAPL should weighted stack technique. The amplitude show as high amplitudes present on the far offset anomalies observed on the far offset stack are section , but not on the near offset section. The present. The anomaly observed on the far offset second AVO analysis technique used was the range limited stack at shot point 79 at 89 ms is Smith and Gidlow "fluid factor" stack (Smith present as is the other anomalies at shot points and Gidlow, 1987) (Fig. 7 bottom). 297 at 109 ms and shot point 430 at 110 ms. However, it must be pointed out that any The "fluid factor" stack is derived from the Aki anomaly above 100 ms must be treated with and Richards (1980) approximation of Zoeppritz caution, because the fluid factor analysis equations and the Castagna, Batzle and assumes 100% water saturation. The water table Eastwood (1985) "mudrock line" for 100% at the M-Area seepage basin occurs at water saturated clastic silicate rocks. In this approximately 100 ms; therefore, any anomaly method a series of time and space variant above 100 ms in not at 100% water saturation weighting factors are applied to the CDP gather unless it is perch water. after NMO (normal moveout) corrections. If the model is valid, the CDP stack will be zero for 100% water saturated clastic sediments. Any

N-10 -u

Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

"MQ'fiW' inftu1

0;C1W i"IiY 6 ;!4 111 4C,4A ?1I P 119C3 ?L19 v~ CDP

];g=}

CDF

lo IT

Figure 7. Offset range limited stacks and fluid factor stack for profile M-1. Near offset section (top), far offset (middle), and fluid factor (bottom). The middle section was generated by stacking offsets greater than 58 feet. High amplitudes that occur only at far offsets should denote presence of DNAPL. Every second trace is plotted. CDP spacing is one foot. The bottom section is a fluid factor stack of M-1. The water table occurs at a depth corresponding to approximately 100 ms time. The amplitude envelope (magnitude of Hilbert transform) is displayed.

data are acquired some basic modeling has to be CONCLUSIONS done. The modeling will determine what is the minimum amount of DNAPL that can be imaged At the M-Area seepage basin, Savannah River given the geologic conditions for a particular site Site it appears that DNAPLs can be imaged in and provide the necessary data for designing the subsurface using high-resolution seismic seismic acquisition parameters. data. Two wells were drilled on anomalies recognized by the seismic data and DNAPLs ACKNOWLEDGMENTS were found at the predicted depth in parts per million (head space data). Funding for this project was provided by U.S. Department of Energy, Savannah River Site. We Caution must be exercised in applying this would also like to thank Mike Graul at Texseis, technique to other areas. Before any seismic Inc. of providing the initial modeling data. We

N-I1 C go Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 also thank Landmark Graphics Corporation for donating the ProMAX software, Hampson Rutherford, S.S. and Williams, R.H., 1989, Russel Software Services Ltd. for donating their Amplitude-versus-offset variations in gas AVO software, and Seismic Micro Technology sands: Geophysics, v. 54, p. 680-688. for donating their KINGDOM software. Sheriff, R, 1991, Encyclopedic Dictionary of Exploration Geophysics: SEG REFERENCES Geophysical Reference Series No. 1, Society of Exploration Geophysicists, Aki, K. and Richards, P.G., 1980, Quantitative Tulsa, OK, 376 p. Seismology: W.H. Freeman and Co., San Francisco, 932 p. Shuey, R.T., 1985, A simplification of the Zoeppritz equations: Geophysics, v. 50, p. Bortfield, R., 1961, Approximation to the reflection 609-614. and transmission coefficients of plane longitudinal and transverse waves: Smith, G.C. and Gidlow, P.M., 1987, Weighted Geophysical Prospecting, v. 9, p. 485-502. stacking for rock property estimation and detection of gas: Geophysical Prospecting, Castagna, J.P. and Backus, M. M., eds., 1993, v. 35, p. 993-1014. Offset-dependent reflectivity - Theory and practice: SEG Investigations in Verm, R. and Hilterman, F., 1995, Lithology color Geophysics No. 8, Society of Exploration coded seismic sections: The calibration of Geophysicists, Tulsa, OK, 345 p. AVO crossplotting to rock properties: The Leading Edge, v. 14, n. 8, p. 847-853. Castagna, J.P., Batzle, M.L., and Eastwood, R.L., 1985, Relationships between Waddell, M.G, Temples, T.J., and Domoracki, compressional-wave and shear-wave W.J., 1997, Using high-resolution velocities in clastic silicate rocks: reflection seismic to image free-phase Geophysics, v. 50, p. 571-581. DNAPLs at the M-area, Savannah River Site (Abstract): Ann. Mtg. Am. Assoc. Gardner, G.H.F., Gardner, L.W., and Gregory, Petroleum Geologists, Dallas, TX. A.R., 1974, Formation velocity and density-the diagnostic basics for Waters, K.H., 1981, Reflection seismology: A tool stratigraphic traps: Geophysics, v. 39, p. for energy resource exploration: John 770-780. Wiley and Sons, New York, 453 p.

Koefoed, 0., 1955, On the effect of Poisson's Zocppritz, K., 1919, Uber reflexion und durchgang ratios of rock strata on the reflection seismischer wellen durch coefficients of plane waves: Geophysical Unstetigkerlsflaschen: Berlin, Uber Prospecting, p. 381-387. Erdbebenwellen VII B, Nachrichten der Koniglichen Gesellschaft der Looney, B.B., 1992 "Assessing DNAPL Wissenschaften zu Gottingen, math-phys. Contamination in A/M Area, SRS: Phase K I., p. 57-84. 1," WSRC-RP-92_1302, Prepared for the U.S. Department of Energy under Contract No. DE-AC09-89SR18035, p 1 85. Mavko, G., Mukerji, T. and Dvorkin, J., 1998: The Rock Physics Handbook: Cambridge University Press, p 1-220.

Ostrander, W.J., 1984, Plane-wave reflection coefficients for gas sands at non-normal angles of incidence: Geophysics, v. 49, p. 1637-1648.

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Geology: Improving Environmental Cleanup of the A/M Area, Savannah River Site

3 Mary K. Harris', D. G. Jackson', Brian B. Looney', Andrew D. Smits2, and R. S. VanPelt

2'Savannah River Technology Center, Aiken SC Science Applications International Corporation, Augusta GA 3Environmental Restoration Division, Savannah River Site, Aiken SC

Introduction A/M Area environmental clean-up program, present a brief background of A/M Area, Successful environmental cleanup programs provide a summary of the local geologic rely on an interdisciplinary team of scientists conditions, and provide detail from a few - geologists, engineers, chemists, specific A/M area geology studies. In the mathematicians, and others. The solutions conclusions, we relate the various geological developed by the team are based on focused findings to specific clean-up technology and environmental characterization followed by implementation decisions within the program. selecting and deploying clean-up technologies that are matched to the problem. Each Anatomy of a Contaminated Site technological advance is grounded in a clearly stated conceptual model that is continually Figure 1 depicts a conceptual diagram of a developed and refined using the scientific contaminated site that has impacted its method. Successful technologies always obey surroundings - in this case, the underlying soil natural laws, and often rely on natural and groundwater. The three ovals - the processes or capabilities. In the work, source zone, the primary contaminant plume, geology plays a particularly important role. and the dilute fringe - represent different Stratigraphy and hydrostratigraphy control portions of the impacted environment that both the migration of contaminant plumes and each have a different character. The source the performance of cleanup technologies. zone contains significant contamination in Understanding depositional processes and concentrated and hazardous forms. The post-depositional alterations - erosional source zone can contain materials such as features and the like - are critical to proper undissolved organic liquids (oils, fuels or selection and optimization and ultimate solvent), strong acids or bases, high levels of success of cleanup. Cleanup of the A/M Area radiation, and/or toxic chemicals or elements. of the Savannah River Site exemplifies both The second oval, the primary contaminant the interdisciplinary nature of the work, as plume, is comprised of contaminated well as the pivotal role of geology. groundwater or vapor that carries pollutants at lower levels, but levels that still represent a Objective potentially significant present or future hazard. The third oval, the dilute fringe, The primary goal of geological support in the contains contamination at relatively low A/M Area is to assist in safe and effective concentrations, but in large volumes of water. operations and in environmental stewardship. This overall objective requires comprehensive Efficient and effective environmental clean up geological activities including both basic and requires matching the character of the clean applied studies. These include a wide variety up and stabilization methods to the character of invasive, noninvasive and data of the target zone of contamination. Thus, interpretation tools. In the sections, below, aggressive and relatively expensive methods we introduce the general philosophy for the are often appropriate for the source zone,

0-1 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 classical pump-and-treat methods are often This complexity must be recognized when good for the primary contamination zone, and developing and implementing technologies for various methods based on natural processes both characterization and clean up of the are often best for the dilute fringe. Figure 1 primary contaminant plume. identifies several example technologies that are appropriate for each of the zones. The dilute fringe contains low concentrations of contamination in large volumes of water. Figure 2 extends this conceptual model by Thus, the best technologies for this zone are identifying the cost basis for the typical clean those that are priced in terms of time ($ / year up technologies. In the source zone, and the like). To be successful, these stabilization and removal methods are technologies must rely on natural-sustainable normally priced in terms of volume of soil or measurable processes. This class of amount of contaminant in the treatment zone technology has gained recent regulatory ($ per cubic yard treated, $ per pound and the support under the terminology "monitored like). The reference source zone technologies natural attenuation". For the dilute fringe, require aggressive access and subsequent use technology selection is biased toward of targeted energy or chemical reagents. It is understanding the contaminant destruction clear that in the source zone it is important to and stabilization capabilities of native species characterize the site in such a way that the and natural populations. A second step is precise location of the source zone is identifying engineering interventions, if delineated as carefully as possible as increases needed, to maximize the performance and to in treatment volume result in additional assure that the attenuation process will operate remediation costs. Detailed source for extended periods. As a consequence, characterization reduces costs by focusing logical and cost-effective monitoring energy or reagent to areas where they are strategies are critical to the success of "natural needed. Equally important, however, is a attenuation" technologies. desire to minimize any undesired negative impacts (wasting energy, harming The three zones depicted in Figure 1 are microbiological populations, etc.) associated present at contaminated sites of all sizes. At a with using aggressive remedies on regions "mom-and-pop" gas station, the entire without source level contamination. contaminated zone - all three ovals - might occupy a portion of a city block. At a large In the primary contaminant plume, treatment industrial facility like the AIM Area at SRS, technologies are normally priced in terms of the contaminated zone can extend over a few the amount of water (or vapor) treated ($ per square miles. The size of a problem impacts gallon and the like). Thus, the goal of how distinct the actions to address the characterization in this portion of the plume is different zones need to be. Time is also a to define the flow directions and general factor. Concentrations change, as cleanup plume structure to allow the most contaminant progresses, so that dilute fringe technologies to be treated in the fewest "gallons". Figure 3 become appropriate for polishing areas that illustrates an important-final extension to our were formerly at higher concentrations. simplified conceptual model. This diagram of the primary contaminant plume in A/M Area General Background on A/M Area shows that contamination moves in response to many factors - contaminant release location The Savannah River Site (SRS) is a U.S. and type, geology, sources and discharges of Department of Energy (DOE) facility that was water, and others. The resulting contaminated set aside in 1950 as a controlled area for soil and groundwater zone occupies a production of nuclear materials for national complicated three-dimensional shape rather defense. This report focuses on the A/M Area than the simple ovals that we began with. at the north boundary of the SRS (Figure 4).

0-2 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

This area includes the facilities which were relatively high density of the DNAPL causes used for fabrication of reactor fuel and target it to move in an overall vertical direction, assemblies (M Area), laboratory facilities following a "path of least resistance" through (SRTC), and administrative support facilities zones of highly permeable gravel and coarse (A Area). Operations within the A/M Area grained sand. The DNAPLs tend to slow and resulted in the release of chlorinated solvents spread laterally upon encountering strata to the subsurface (Marine and Bledsoe, 1984). composed of less-permeable silty sand and Released solvents include trichlorethylene clay (Jackson and others, 1996). Potential (TCE), tetrachloroethylene (PCE) and 1,1,1 migration paths and distribution of DNAPL trichloroethane (TCA) which have are therefore related to the distribution and contaminated the soil and groundwater within configuration of less-permeable, fine-grained the area. Since the detection of these volatile sediment. organic compounds (VOCs), the SRS has pursued a program of soil and groundwater Once emplaced within the saturated zone, remediation. DNAPLs serve as a source for the release of dissolved VOCs to the groundwater. The The SRS remediation program integrates groundwater carries dissolved VOCs as technologies to address various portions of the plumes, which emanate from the DNAPL contaminant plume conceptually presented source and extend in a direction earlier. Within the immediate source zone a corresponding to the local hydraulic gradient. series of soil-vapor extraction units are Movement of VOC-contaminated combined with enhanced source groundwater is largely controlled by the removal/destruction methods, and an geometry and distribution of more permeable extensive network of groundwater recovery strata, the nature and extent of the DNAPL wells. This combination provides for the source, and the overall dynamics of water removal of contaminants in the vadose zone recharge and discharge from the subsurface and reduces additional migration in the system. groundwater. The extensive groundwater pump & treat system also provides for the The distribution of fine-grained sediment extraction and treatment of contaminated layers and variations in the quantity of clay groundwater in the primary contaminant zone. and silt within the sediment is extremely A series of vertical recirculation wells treats important in order to fully characterize the groundwater before it enters the dilute fringe. extent of DNAPL layers beneath the A/M SRS maintains an on-site research and Area and determine the geometry of the demonstration program for developing contaminant plumes emanating from them. innovative remediation techniques and Indirect assessment techniques have been maximizing the efficiency and effectiveness of applied to historical groundwater the SRS remediation strategy. The SRS concentrations in the A/M Area and indicate remediation strategy includes on-going that the distribution of DNAPL beneath A/M characterization of subsurface features and Area may be laterally extensive (Jackson and conditions that may have a significant others, 1996). The delineation of layers of influence on groundwater flow and less-permeable sediment is therefore critical to contaminant transport. aid remediation efforts. Detailed mapping of these geologic features can aid in locating Recent characterization efforts emphasize areas where contamination is most likely to locating dense non-aqueous phase liquid have migrated into the saturated zone. These (DNAPL) in the subsurface beneath A/M Area data are valuable aids for accurate modeling (Looney and others, 1992). Upon release at of groundwater flow and contaminant the surface, DNAPL migrates down through transport. In addition, this information can be the vadose zone into the saturated zone. The used to refine the current remediation systems

0-3 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 or assist in designing new ones. The results of Line. Beneath the A/M Area, Cretaceous a recent geospatial mapping study are aged strata rest on crystalline basement rock at presented below to exemplify the work in a depth of 500 to 700 feet below the land A/M Area. surface (ft bls). For a detailed discussion of the lithostratigraphy the reader is referred to A/M Area Geological Setting Wyatt, 2000 (this volume). This paper will concentrate on the hydrostratigraphy of the The SRS comprises approximately 300 square A/M Area. miles within Aiken, Barnwell, and Allendale counties in southwestern South Carolina. The Hydrostratigraphy center of the SRS is 22.5 miles southeast of The hydrostratigraphy of the SRS has been the Augusta, Georgia, approximately 100 miles subject of several different systems of from the Atlantic Coast within the Upper hydrostratigraphic classification. This report Atlantic Coastal Plain Physiographic Province incorporates the hydrostratigraphic (Figure 4). The Savannah River forms the nomenclature currently established for the southwest boundary of the SRS. The SRS lies SRS region and A/M Area by Aadland and on the Aiken Plateau of the Atlantic Coastal others (1995a, 1995b). This study focuses on Plain at an average elevation of 300 feet above the up-dip part of the Floridan-Midville mean sea level (ft msl). The Aiken Plateau is aquifer system as defined for A/M Area by well drained, although many poorly drained Aadland and others (1995b). Strata within sinks and depressions exist, especially in units of the Floridan-Midville aquifer system upland areas. Overall, the Aiken Plateau that exhibit internally consistent hydraulic displays highly dissected topography, characteristics and which, on a local scale, characterized by broad inter-fluvial areas behave as distinct hydrostratigraphic units, are separated by narrow, steep-sided valleys. delineated as informal aquifer and confining Local relief can attain 280 feet (Siple, 1967). zones (Aadland and others, 1995b). Figure 6 The A/M Area comprises approximately eight correlates the nomenclature of Aadland and square miles near the northern boundary of the others (1995b) with the lithostratigraphy of SRS (Figures 4 & 5). Fallaw and Price (1995).

Lithostratigraphy The hydrostratigraphy of the A/M Area The SRS is underlain by sediment of the consists of three aquifers within the Floridan Atlantic Coastal Plain. The Atlantic Coastal Midville aquifer system divided by one Plain consists of a southeast-dipping wedge of confining unit and one confining system. In unconsolidated and semi-consolidated the vicinity of SRS, this aquifer system sediment that extends from its contact with the includes, the McQueen Branch aquifer, Piedmont Province at the Fall Line to the edge overlain by the Crouch Branch aquifer, and of the continental shelf. These deposits consist the Steed Pond aquifer. The Crouch Branch of sediment that is deltaic and near-shore aquifer is the principal water-producing marine in origin, with evidence of aquifer at SRS and is the deepest unit that is considerable fluvial influence (Fallaw and routinely sampled by the current monitoring Price, 1995). The sediment consists of well system. Since the principle components interbedded sand, muddy sand, and mud (clay of large scale contaminant migration in the and silt), with a subordinate amount of A/M Area are dissolution of source (DNAPL) calcareous sediment. Strata range from Late solvents followed by dissolved transport Cretaceous to Miocene in age and rest within the shallow aquifers overlying the unconformably on crystalline and sedimentary Crouch Branch aquifer, the information basement rock (Figure 6). The A/M Area lies selected for presentation below addresses within the up-dip area of the coastal plain critical features of the Steed Pond aquifer and deposits, approximately 20 miles from the Fall

0-4 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 the nature of the aquitard between the Steed Lithofacies Mud Mapping of Critical Pond aquifer and Crouch Branch aquifer. Intervals in A/M Area

Within the A/M Area, the flow of shallow Geologic drill core descriptions and groundwater is controlled by numerous local geophysical logs (caliper, gamma-ray and and regional parameters. These parameters resistivity) for 42 cores were utilized in this include the influence of the Savannah River to study to delineate hydrostratigraphic the west of the A/M Area, the facies changes boundaries beneath the study area (Figure 5). within the Crouch Branch confining zone in The drill core descriptions are detailed and the northeast portion of the study area, the provide a foot-by-foot microscopic description topographic relief that creates a strong which includes percent mud, gravel, and sand downward gradient through out the entire along with estimated porosity and sorting A/M Area, and the incision of locally characteristics. Altitude contour maps, important confining zones due to erosion in isopach maps, and lithofacies maps were the southern portion of the study area. produced for each hydrostratigraphic unit using EarthVision® software (Dynamic The majority of the groundwater Graphics Inc., Alameda CA, www.dgi.com). contamination in the A/M Area is located in Lithofacies maps were created to depict the the Steed Pond aquifer and is the target of lateral distribution of mud and the internal current remediation activities. This aquifer variation of the mud content within the unit contains the water-table unit. In the Central using the geometric mean and standard A/M Area the Steed Pond aquifer is divided deviation of the parameter. The maps of the into the M-Area and the Lost Lake aquifer geometric mean are interpreted as an average zones, which are separated by the Green Clay expression the overall mud content within the confining zone. Towards the north, in the unit while the standard deviation provides an vicinity of the SRTC complex, these units are indication of the degree of vertical lithologic not well distinguished and the unit is treated variation, such as interbedding of sediment as one aquifer unit. The elevated topography, types within the unit. Both of these location of drainage features, and the lithofacies parameters are functions of the numerous interbedded layers of sands, silts thickness of the unit. Isopach maps and and clays combine to create a predominately geometric mean mud content maps for downward flow direction within the aquifer. selected hydrostratigraphic units are presented In the southern region of the study area the M in this paper. The Crouch Branch confining Area and Lost Lake aquifer zones become unit and the Green Clay confining zone will distinct hydrologic units due to increased be discussed in detail. For discussion of the thickness of clays within the Green Clay other hydrostratigraphic units the reader is confining zone. The groundwater flow is referred to Smits and others, 1998, and Parker strongly downward in the M-Area aquifer and others, 1999. zone in this region. Upon entering the Lost Lake aquifer zone the flow transitions to the Crouch Branch Confining Unit lateral direction and is controlled by regional discharges to surface streams towards both the The Crouch Branch confining unit separates south and the southeast. At the extreme the Crouch Branch aquifer from the Steed southeastern portion of the study area, erosion Pond aquifer (Figure 6). The Crouch Branch of the Green Clay confining unit has resulted confining unit may be divided into three in the outcropping of the contaminant plume hydrogeologic zones beneath the A/M Area contained in the Lost Lake aquifer zone. (Aadland and others, 1995b). These zones, in ascending order, are the "lower clay" confining zone, the "middle sand" aquifer zone, and the "upper clay" confining zone. As

0-5 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 described below, the "upper clay" confining the study area to 90-95% in the southern part. zone thins and disappears toward the northern In contrast, this interval of the Crouch Branch edge of A/M Area. In this region, the "middle confining unit contains relatively low sand" aquifer zone coalesces with the quantities of mud beneath the northeast corner overlying "Lost Lake" aquifer zone of the of the study area, corresponding to the Steed Pond aquifer. In the western part of the channel-like feature beneath A Area. This A/M Area, these zones are not delineated due interpretation is further supported by small to the absence of the sand beds referred to as standard deviations in this area which the "middle sand" aquifer zone. In the represent clean well-sorted sands indicative of northeastern portion of the area the clay beds fluvial deposition. In contrast, the areas of of the "upper clay" and "lower clay" zone of low mud percentages with higher standard the unit are thin or absent. It is in this region deviations are interpreted to represent where groundwater flow occurs between the interbedded sands and clays of fluvio-deltaic overlying Steed Pond aquifer and the origin. underlying Crouch Branch aquifer (Aadland and others, 1995b). The interpretation "Middle" Interval of the Crouch Branch outlined below is supported by a recent confining unit geophysical study that creatively combined The surface of the "middle" interval of the the results of time domain electromagnetic Crouch Branch confining unit ranges from (TDEM) soundings and shallow seismic 105 to 140 ft msl and varies in thickness from reflection surveys to characterize the Crouch 46 ft to 3 ft (Figure 9). The isopach map Branch confining unit (Eddy-Dilek and others, indicates that thick parts of this interval 1997). The geophysical study was generally correspond with channel-like particularly successful in noninvasively features on the top of the "lower" interval. corroborating both the position and The mean mud fraction varies from less than lithological character of the Crouch Branch 5% to greater than 60%. The larger mud confining unit (e.g., areas where the Crouch percentages generally correlate with the Branch confining unit is dominated by sand). thinner parts of the interval, especially in the southern sector of the A/M Area and in the "Lower" Interval of the Crouch Branch western part of the study area (Figures 9 and confining unit 10). The standard deviation of the mud The surface of the "lower" interval of the fraction within the "middle" interval is higher Crouch Branch confining unit ranges from in areas where the mean mud fraction is 119 to 75 ft msl and dips to the south higher. These fine-grained muddy sediments southeast. The isopach map of this interval of the "middle" interval of the Crouch Branch indicates a variation from 17 to 60 ft in confining unit are interpreted to represent thickness (Figure 7). The "lower" interval of interbedded layers of sand and mud that are the Crouch Branch confining unit is generally not laterally extensive. thicker in areas that correspond with channel like features on the top of the Crouch Branch "Upper" Interval of the Crouch Branch aquifer. These variations are attributed to confining unit depositional fluvial facies changes such as The surface of the "upper" interval ranges channel and point bar deposits. from 117 to 158 ft msl and varies in thickness from 5 to 46 ft (Figure 11). Two channel-like Figure 8 illustrates the geometric mean of the features were recognized in this interval, one mud percentage within the "lower" interval of that trends northwest to southeast beneath A the Crouch Branch confining unit. The and M Areas and the other in the western geometric mean of the mud percentage is portion of the study area. The mean mud generally high which corresponds to thick fraction ranges from less than 5% to greater intervals, ranging from 75% in the center of than 80%. Areas with high mean mud values

0-6 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 correspond with thin parts of the interval aquifer zone consists of orange to tan and (Figures 11 and 12). Standard deviation of yellow, fine to coarse, poorly to well-sorted this interval indicates high internal variability sand of the Tobacco Road and Dry Branch of the mud content. Where significant formations (Fallaw and Price, 1992). Pebbly amounts of clay do exist, they are highly layers, interbedded clay laminae, and clay interbedded with sand. As with the "lower" interbeds (up to 8 ft thick) are common. Only and "middle" interval the northeastern portion the Green Clay confining zone will be of the study area has a sporadic distribution of discussed in detail. The Green Clay confining mud. The areas of mean mud values greater zone was theorized to be a principle control than 50% within the "upper" interval probably on the accumulation and migration of DNAPL define the areal extent of the "upper clay" below the water table in A/M Area (Looney confining zone of the Crouch Branch and others, 1992). This hypothesis was confining unit (Figure 12). The absence of further supported using indirect DNAPL significant quantities of mud from all three characterization techniques along with intervals in the northern sector of the A/M heuristic DNAPL modeling (Jackson and Area indicates that the Steed Pond aquifer is others, 1996). probably in hydraulic communication with the Crouch Branch aquifer in this part of the study Green Clay confining zone area. The surface of the Green Clay confining zone varies from 197 to 223 ft msl with thickness Steed Pond Aquifer varying from 9 to 32 ft (Figure 13). The Green Clay confining zone is generally thicker The Steed Pond aquifer is composed primarily in the southern part of the study area. The of sand and clayey sands interbeds (Aadland thicker areas are related to the channel-like and others, 1995b). The Steed Pond aquifer is features in the Lost Lake aquifer zone. The divided into the M Area aquifer zone, Green Green Clay confining zone is interpreted to Clay confining zone, and Lost Lake aquifer represent a fluvio-deltaic environment with zone (Figure 6). The Lost Lake aquifer zone varying amounts of nearshore marine consists of yellow, tan, orange, and brown , influence. loose to slightly indurated, fine to coarse, moderately to well-sorted, occasionally pebbly The mean mud content within the Green Clay sand and minor clayey sand. The Green Clay confining zone varies from less than 5% to confining zone overlies the Lost Lake aquifer greater than 50% and is significantly higher in zone. This zone is considered correlative with the southeast corner and southern edge of the the clay and silty clay beds of the Gordon study area (Figure 14). The isolated thick area confining unit of the Floridan aquifer system northeast of A Area is characterized by south of Upper Three Runs (Aadland and relatively small mud percentages. The Green others, 1995b). In the A/M Area the Green Clay confining zone contains very little mud Clay confining zone consists of primarily at the western end of the study area. The orange and yellow, fine to coarse, poorly to standard deviation of the mean mud well-sorted, often pebbly sand and clayey sand percentages is generally greater in the areas interbedded with gray, green, and tan clay to with larger mud fractions. The parts of the silty clay beds (Fallaw and Price, 1992). Green Clay confining zone that lack mud tend Aadland and others (1995b) consider these to be thicker, and show smaller standard clay and silty clay beds the Green Clay deviation values. This indicates that the confining zone when they are sufficiently Green Clay confining zone consists primarily thick and continuous. The M Area aquifer of sand, with moderate amounts of zone extends from the water table to the top interbedded clay present in the southeastern of the Green Clay confining zone (Aadland part of the study area where the unit is and others, 1995b). In A/M Area the M Area relatively thin. The maps of mud distribution

0-7 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 indicate that the zone is probably a competent comparison to the "lower" interval. The confining zone southeast of the M Area Basin. "lower interval" consists primarily of thick The low mud percentages and low standard clay layers with high mud percentages in the deviation values west of the M Area Basin central and southern sectors of the study area suggest that the Green Clay confining zone is and represents the most competent and relatively permeable in this area. extensive portion of the Crouch Branch confining unit. The absence of significant Summary and Conclusions quantities of mud from all three intervals in the northern sector of the A/M Area indicates The distribution of mud layers and variations that the overlying Steed Pond aquifer is in in the percentage of fine-grained sediments in hydraulic communication with the Crouch the subsurface is essential in characterizing Branch aquifer in this region. This facies and understanding the DNAPL accumulation, change is probably a significant contributor to movement, and geometry of the resulting the migration of dissolved contamination from contaminant plumes beneath the A/M Area. the Steed Pond aquifer into the Crouch Branch In general, characterizing the nature and aquifer (Jackson and other, 1997). distribution of confining zones in Coastal Plain sediments is challenging. These The Green Clay confining zone is within the sediments were deposited by fluvial, deltaic, Steed Pond aquifer and has a mean mud and/or coastal processes and are often altered content ranging from approximately 5% to by post depositional erosion and weathering. 50%. While this zone is relatively thin and As a result, they exhibit significant lateral and sandy it contains enough fine-grained vertical variations typical of ephemeral sediment to control the accumulation and depositional settings. Variations in lithology migration of DNAPL below the water table and stratigraphy can occur abruptly or near known sources (e.g., the M-Area Settling gradually. Abrupt changes can occur due to Basin). This is illustrated in Figure 15 that local depositional environment (e.g., presents the results of a DNAPL screening meanders), structural modification, (e.g., analysis where the pure-phase solubility was faults), and erosional events (e.g., compared to historically reported unconformities). Gradual changes are often groundwater. Screening of historical more difficult to evaluate and are often concentrations against 1% of pure-phase manifested in coarsening or fining of solubility identified 43 monitoring wells and sediments vertically or along the dip of a bed. 10 recovery wells that likely contained Precision mapping of critical sediment layers DNAPL within the A/M Area. can aid in locating areas where contamination is most likely to have migrated. Additionally, The geological characterization has had this information can be used to refine specific impacts on the design and operation remediation systems or assist in designing of the A/M Area environmental clean-up. new systems. Near the original DNAPL sources, delineation of confining layers above and below the water The mud distribution for the "lower", table is the basis for design of sampling "middle", and "upper" intervals of the Crouch strategies and for targeting aggressive Branch confining unit indicates a series of treatment technologies. Below the water facies changes beneath the study area. The table, these structures impede downward distribution of mud in the northern sector of migration and serve to control accumulation the study area indicates all three intervals of solvent into thin-laterally-extensive layers consist primarily of sand. In the remainder of of contaminant rich fluid within overlying the study area, the "middle" and "upper" sand and ultimately into "pools" occupying intervals both consist primarily of sand, with a structural lows. One such area, southwest of relatively sporadic distribution of mud in the M-Area Settling Basin, was identified

0-8 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 using geophysics and sampling and was about the Crouch Branch confining unit. The treated using injection of Fenton's reagent observed facies changes - the thinning and (Jerome and others, 1997). Above the water more sandy character of this major table, our data indicate that residual DNAPL hydrostratigraphic "confining unit" near A solvents are trapped within fine-grained Area - was the basis of modification of the sediment layers. As a result, we performed pump and treat operation. To minimize future geological investigations of these shallow downward migration and contamination of the intervals (Parker and others, 1999) and have Crouch Branch aquifer, increased water identified and implemented source treatments treatment capacity was installed and the that have specific abilities to overcome the number of recovery wells and pumping rate in mass transfer limited clean-up rates. The shallow groundwater in A Area was three enhanced remediation technologies aggressively expanded. These modifications tested to date are heating technologies - steam represent a significant improvement in long heating (Dynamic Underground Stripping, term protection of the important Crouch DUS), radio frequency heating (Jarosch and Branch aquifer for a relatively low cost. others, 1994), and six phase joule heating (Gauglitz and others, 1994). The differences Finally, the geological and chemical data in technology selection for the different indicated that the bulk of the plume is source scenarios is a direct result of migrating toward Tim's Branch and Upper controlling geological conditions and the Three Runs and suggested likely areas of observed interaction of contaminant with the future plume discharge. Recently, passive subsurface materials. samplers placed in active flow lines near the projected groundwater-surface water Once the contaminant dissolves from the discharge area have confirmed this conceptual source zone, the resulting plume migrates with model. Geological considerations, the groundwater toward the discharge along particularly knowledge of the area where the Tim's Branch and Upper Three Runs. The stream channel has eroded below the green focus for geology contribution to remedial clay, were critical in successfully determining design shifts to understanding the precise the location of the future contaminated trajectory of the contaminant plume. We groundwater discharges (since the plume is in optimize the performance of "pump and treat" the middle of the Lost Lake aquifer in the remediation using knowledge of the plume southern portion of A/M Area). The flow path centerline and by careful placement of knowledge is now available for design and recovery well screens. Geological implementation of effective long term information and depth discrete sampling remediation concepts. Two examples of such performed during recovery well installation concepts are phytoremediation and microbial allow maximum efficiency because design can degradation in the wetland sediments adjacent be customized to extract the maximum amount to the stream. of contaminant in the minimum volume of water. Similarly, the in well vapor stripping Delineation of the hydrogeologic framework systems installed in A/M Area were designed of a contaminated site is a critical component with the intake screen centered in a carefully of effective environmental characterization identified discrete layer of contamination that and remediation. A/M Area demonstrates that occupied only a portion of the Lost Lake development and refinement of a conceptual aquifer - maximizing system efficiency. model using a variety of approaches, including drilling, coring, geophysical logging, aquifer A particularly significant example of the testing, surface geophysics, modeling and data importance of geology in the A/M Area clean interpretation, enhances decision making and up is the change made to the groundwater technical performance. corrective action system based on knowledge

0-9 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

References WSRC-RP-06-0574, Westinghouse Savannah River Company, Aiken, SC 29808. Aadland, R. K., Gellici, J. A, and Thayer, P. A., 1995a. Hydrogeologic Framework of Jackson, D. G., B. B. Looney, and H. W. West-Central South Carolina,Report 5, Water Campbell. 1997, Assessment of Chlorinated Resources Division, South Carolina Solvent Contamination in the Crouch Branch Department of Natural Resources, Columbia, Aquifer of the A/M Area (U). WSRC-RP-97 SC. 0247: September 30, 1997. Westinghouse Savannah River Company, Aiken, SC 29808. Aadland, R. K., Lewis, S. E., and McAdams, T. D. 1995b. Hydrogeological Jarosch, T. R., Beleski, R. J., and Faust, D., Characterization Report for the A/M Area 1994, Final Report: In Situ Radio Frequency (U). WSRC-RP-95-0052, Westinghouse Heating Demonstration, WSRC-TR-93-673, Savannah River Company, Aiken, SC 29808. Westinghouse Savannah River Company, Aiken, SC 29808. Eddy-Dilek, C. A., Looney, B. B., Hoekstra, P., Harthill, N., Blohm, M., and Phillips, D. Jerome, K. M., Riha, B. D., and Looney, B. R., 1997. "Definition of a Critical Confining B., 1997, Final Report for Demonstration of Zone Using Surface Geophysical Methods", In Situ Oxidation of DNAPL Using the Geo Ground Water, v. 35(3): 451-462. Cleanse'• Technology, WSRC-TR-97-00283, Westinghouse Savannah River Company, Fallaw, W. C. and Price, V., 1992. "Outline of Aiken, SC 29808. Stratigraphy at the Savannah River Site", Geological Investigations of the Central Looney, B. B., Rossabi, J. R., and Tuck, D. Savannah River Area, South Carolina and M., 1992. Assessing DNAPL contamination, Georgia, Fallaw, W. C., and Price, V., eds., A/M-Area, Savannah River Site: Phase I Carolina Geological Society Field Trip Guide Results (U), WSRC-RP-92-1302, Book, November 13-15, 1992, CGS-92-B-1 1 Westinghouse Savannah River Company, 1-33, U.S. Department of Energy and S.C. Aiken, SC 29808. Geological Survey. Marine, 1. W. and Bledsoe, H. W. 1984. Fallaw, W. C. and Price, V., 1995. Supplemental Technical Summary M-Area "Stratigraphy of the Savannah River Site and Groundwater Investigation, DPSTD-84-0112, Vicinity", Southeastern Geology, 35: 21-58. E. I. du Pont de Nemours & Co., Savannah River Laboratory, Aiken, SC 29808. Gauglitz, P. A., Bergsman, T. M., Caley, S. M., Heath, W. 0., Miller, M. C., Moss, R. W., Siple, G. E., 1967. Geology and Ground Roberts, J. S., Schalla, R., Schlender, M. H., Water of the Savannah River Plant and Jarosch, T. R., Eddy-Dilek, C. A., andLooney, Viciniti, South Carolina, U.S. Geological B. B., Six Phase Soil Heating for Enhance Survey Water Supply Paper 1841. Removal of Contaminants: Volatile Organic Compounds in Non-Arid Soils Integrated Smits, A. D., Harris, M. K., Jackson, D. G., Demonstration, Savannah River Site, PNL and Hawkins, K. L., 1998, Baseline Mapping 10184, Pacific Northwest National Study of the Steed Pond Aquifer and Crouch Laboratory, Richland WA. Branch Confining Unit Beneath A/M Area, Savannah River Site, Aiken, South Carolina Jackson, 1). G., Payne, T. H., Looney, B. B., (U), WSRC-RP-98-00357, Westinghouse and Rossabi, J. R., 1996, Estimating the Savannah River Company, Aiken, SC 29808. Extent and Thickness of DNAPL within the A/M Area of the Savannah River Site (U),

0-10 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Parker, W. H., Smits, A. D., Harris, M. K., Jackson, D.G., and Hawkins, K.L, 1999, Baseline Mapping Study of the Steed Pond Aquifer and Vadose Zone beneath A/M Area, Savannah River Site, Aiken, South Carolina (U), WSRC-RP-99-00295, Westinghouse Savannah River Company, Aiken, SC 29808.

Wyatt, D. E., Aadland, R. K., and Syms, F. H., 2000, Overview of the Savannah River Site Stratigraphy, Hydrostratigraphy, and Structure (This volume).

0-11 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Anatomy of a Contaminated Site

Wste

SourceZone Charactedstics Dilute Plume I Fringe High Concentrations Primary Groundwater I Characteristics: Significantly perturbed Vadose Zone Plume Low aqueous/vapor geochemistry Characteristics: phase concentrations; Need: Moderate to high aqueous/vapor Large water volume Aggressive technologies phase concentrations Need~innovative to limit long temi damage technologies - sustainable Need:Baseline methods or Exampoles: moderately aggressive alternatives low energy concepts destruction or stabilization ExamplesPassive pumping in place; heatsteam; Examplesrump (gas or water) and (siphon, barometric, etc.); chemical oxidation or treat;recirculatioiwelts; enhanced bioremediaticphytorem ediation reduction; immobilization. bioremediation geochemicastabilization

Figure 1: Conceptual Diagram of a Contaminated Site

Diagnosing and Treating a Contaminated Site

site

4

Source Zone Costs: Dilute Plume/Fringe $Ab contaminant or Primary Groundwater! Vadose $/cu Costs: Zone Plume yd. Removal Operation and examples: Costs: maintenance costs $/time "<$50 $100/cu yd or S/treatment volume (gallon/cu ft) mass transfer "<$100/b forchlorinated example: and flux characterization needed solvents $0.5-41 /11000 gallons hot spot characterization zone of capture characterization reduces cleanup volume needed, optimize extraction to reduce treatment volume

Figure 2: Conceptual Diagram of a Contaminated Site with cost considerations for clean-up technologies W 0-12 ý Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Figure 3. Cut-away diagram showing the 3D structure of a real groundwater plume

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0-13 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Study Area U 1 9' -

S

N Vt IL Miles Miles

Figure 4: Location of the Savannah River Site and the A/M Area

Figure 5: Detailed map of A/M Area illustrating core locations

0-14 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

CHRONOSTRATIGRAPHIC LITHOSTRATIGRAPHIC UNITS HYDROSTRATIGRAPHIC UNITS UNITS (Modified from Fallaw and Price, 1995) (Modified from Aadland and others, 1995a)

ERA System Series Group Formation Miocene(?) "Upland" unit ground sura-ce Tobacco Road Sand vadose zone

Upper Dry Branch table Barnwell Formation "znaie,

Group 0 Clinchfield Eocene Formation " "M Area" aquifer zone 0 e -n in Santee 0 0 en Orangeburg Fonnation 0' Middle Group Warley Hill Formation 'greeinclay` confiniing zone 0

Congaree Formation "Lost Lake" aquifer zone Lower Fourmile Branch Formation

N Upper Black Snapp Formation 7 .=. "K "middle sand" .:_ Crouch Branch Paleoceiie Mingo Lang Syne Formation 0. Lowver aquifer zone _. confining unit -t (.) Group Sawdust Landing Formation 0 en 0 0 Steel Creek Formation Crouch Branch aquifer in Black Creek 9

0 0 0 Group McQueen Branch confining unit Upper Cretaceous in in en

C-) Middendorf Formation McQueen Branch aquifer

Cape Fear Formation Appleton confining system C- Newark Neaprkr in Sedimentary Rock (Dunbarton Basin) Supergroup Piedmont Hydrogeologic Province

Crystalline Basement Rock 2 C.) a-

Figure 6: Comparison of Chronostratigraphic, Lithostratigraphic, and Hydrostratigraphic Units

0-15 -s

Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

+!

Figures 7 & 8: Isopach and Geometric Mean Mud percentage in the "Lower" interval of the Crouch Branch Confining Unit

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Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

I

Figures 9 & 10: Isopach and Geometric Mean Mud percentage in the "Lower" interval of the Crouch Branch Confining Unit

017 I

Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Figures 11 & 12: Isopach and Geometric Mean Mud percentage in the "Lower" interval of the Crouch Branch Confining Unit

C, -d,, (,, ý, 0-t8 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Figures 13 & 14: Isopach and Geometric Mean Mud percentage in the Green Clay Confining Zone

019 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

r :

S......

Figure 15: Monitoring Wells considered to have DNAPL contamination based on screening analysis comparing the pure-phase solubility to historically reported groundwater concentrations (Jackson and others, 1996).

0 20 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Short Note: Seismic Monitoring at SRS

D. Stevenson, WSRC, Aiken, SC 29808

INTRODUCTION In addition to local events, regional earthquake activity occurring outside the relatively small The Savannah River Site (SRS) has been area covered by the SRS monitoring network operating and maintaining a continuous also has the potential for significantly recording seismic network on Site since the impacting seismic safety considerations of the mid-seventies. The network was developed to Site. Good quality regional seismic data are monitor Site and regional seismic activity that required when defining the range of may potentially impact the safety of existing or seismogenic sources that may influence planned structures and systems at SRS. estimates of Site vibratory ground motion as Operation and maintenance of the network is an well as identification of possible seismically important ongoing task contributing to Site active tectonic features. Regional coverage is seismic hazards analyses. It provides SRS with currently provided cooperatively with the earthquake data collection and analysis University of South Carolina through data from capability to insure accurate reliable the SCSN (South Carolina Seismic Network). information on current earthquake activity that The University of South Carolina seismic may occur within the immediate Site vicinity. network stations serve to compliment the SRS Additionally, network seismic data directly network contributing greatly to the regional and addresses seismic safety considerations by Site area seismic monitoring effort. providing an historical background database documenting levels of seismic activity On-Site Earthquake Activity impacting the Site through the years. Three earthquakes of MMI III or less have Current station configuration includes nine occurred with epicentral locations within the short-period seismic recording stations, six are boundaries of SRS (Figure 2). On June 9, confined within the plant boundary with an 1985, an intensity III earthquake with a local additional three off-Site (Figure 1). The off duration magnitude of 2.6 occurred at SRS. Felt site station locations are within a 10 to 50 km reports were more common at the western edge radius from the center of the SRS. Currently, of the central portion of the plant site. Figure 3 we have a mix of digital and analog stations shows the resulting isoseismal intensity map. depending on quality of communication link Another event occurred at SRS August 5,1988, between the field and the central recording with an MMI 1-11 and a local duration laboratory. One station, Hawthorne Firetower, magnitude of 2.0. A survey of SRS personnel has a unique configuration consisting of both a who were at the plant during the 1988 short-period and long period instrument housed earthquake indicated that it was not felt at SRS. in a borehole package. This instrumentation Neither of these earthquakes triggered the package is presently installed in a relatively seismic alarms (set point 0.002g) at SRS shallow borehole (100ft). However, through a facilities. These earthquakes were of similar cooperative effort with the USGS, drilling of a magnitude and intensity as several recent deeper bedrock hole (-1000 ft) at the same events within the region. location is planned for January 2001. Upon On the evening of May 17, 1997, at 23:38:38.6 completion of a deeper hole the existing sensor UTC (7:38 pm EDST) an MD - 2.3 (Duration It is hoped that the package will be re-deployed. Magnitude) earthquake occurred within the station will then become a part of the USGS boundary of the Savannah River Site. It was National Seismic Network. reported felt by workers in K-Area and by

P-1 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Wackenhut guards at a nearby barricade. An SMA (strong motion accelerograph) located 3 miles southeast of the epicenter at GunSite 51 was not triggered by the event. The SMA located approximately 10 miles (16 km) north - N ' , of the event in the seismic lab building 735- 'I 1 A was not triggered. The closest instrument to the epicenter (GunSite 51) is set at a trigger threshold of 0.3% of full scale where full scale is 2 .Og (0.006g). The more distant lab SMA is settotriggeratathresholdof0.1%of full scale where full scale is !.Og (0.001g)."b•PD Other Seismic Monitoring Efforts at SRS Monitoring of structural response to earthquake , motions is being done through deployment and "" 4 operation of accelerographs (strong ground motion recorder) in ten selected mission-critical structures. Instrument placement ranges from foundation level, selected elevations and in the .. free-field depending on the structure being studied. Free-field instrumentation data will be used to compare measured response to the design input motion for the structures and to Figure 1. SRS short period recording stations determine whether the OBE has been exceeded. The instruments located at the foundation level and at elevation in the structures will be used to compare measured response to the design input motion for equipment and piping, and will be used in long-term evaluations. In addition, foundation-level instrumentation will provide data on the actual seismic input to the mission critical structures and will be used to quantity differences between the vibratory ground motion at the free-field and at the foundation level. All instruments are Kinemetrics Etna Strong Motion Accelerographs with dial-up modem data download capability. All SMA instrumentation is set to trigger at 2.0% full scale with full scale being Ig (i.e. trigger set at ...... O.O2g).;

Figure 2. Historical earthquake epicenter:S located on the SRS. Triangles with date are historically mis-located. C2A(f P-2 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

EXPLANAT ION

)X INSTRUMENTAL EPICENTER

0/0 NUMBER FELT/NUMBER NOT FELT (BY AREA REPORTING

SCALE IN MILES 0 1 2 3 4 5 602025

Figure 3. Isoseismal Intensity map from the June 9, 1985, intensity Im earthquake.

P-3 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Notes

P-4 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Short Note: Formation Damage Caused by Excessive Borehole Fluid Pressures in Coastal Plain Sediments

D. E. Wyatt, WSRC, Aiken, SC 29808

Introduction been completed on the potential formation During the initial characterization and damage effects caused by hydraulic fracturing engineering studies of the SRS, performed by during casing and cementing activities within the Corps of Engineers, numerous zones of these sediments. Exploration conducted to lost circulation, "grout take" and rod drop investigate the effects of foundation grouting were noted. Large foundation grouting programs showed that large volumes of programs discovered that intervals of "micro injected grout traveled radially, in thin layers, channeling" and fracturing occurred during considerable distances from the borehole. pumped grout programs. Ongoing drilling Intuitive experience from the petroleum activities often report zones of lost circulation industry suggests that formation damage is and rod drop, generally thought to be "soft likely when the hydraulic pressure gradient zones" (see Aadland et al. in this guidebook). from the drilling or grouting exceeds the In many cases rod drops and lost circulation fracture gradient of the formation. Formation are due to soft zones, however an abundance damage may lead to "leaking" of downward of cone penetrometer (CPT) data suggests that moving contaminants or upward moving many coastal plain sediments may be subject groundwater through fractures and micro to hydraulic fracturing during drilling fractures adjacent to the borehole. Hydraulic operations. Hydraulic fracturing may be the over-pressuring may be caused by excessive cause of some of the lost circulation problems mud weight, grout weight or pump over and may cause problems if key aquitards are pressuring. damaged. Approach An Example of the Problem Since few measurements of formation damage State regulations and SRS Drilling Procedures have been made at the SRS, a theoretical require that surface casing be set in approach is made based on data collected at monitoring wells penetrating deeper aquifers the Hydrogeological Field Test Site in well in 1) areas where known contamination exists MWD-12. This well is centrally located at the in overlying aquifers, and 2) areas SRS and is representative of the majority of downgradient from facilities or areas with monitoring wells in the area. MWD-12 was known contamination. Typical casing set completed to provide core information for a points are within the "Green Clay" interval comparison study between core property (Gordon Confining Unit) of the Warley Hill measurements and data obtained from Formation and occasionally within the "Tan geophysical tools, principally the magnetic Clay" interval of the Dry Branch Formation resonance and formation fluid/pressure tester (Tan Clay Confining Zone of the Upper Three (the MRIL and Formation Multi-Tester (FMT) Runs Aquifer). These two units are clayey tools). In addition to core and geophysical aquitards that are generally less than ten feet measurements, Cone Penetrometer Test (CPT) thick for the "Tan Clay" and less than six feet information was also obtained immediately thick for the "Green Clay". Neither of these adjacent to the boring location. CPT data are units are massively bedded clays but generally available to a depth of 153' and geophysical consist of thin to thick (<1" to <2') lamina data to a depth of 342'. interspersed within clayey silts and fine grained sands. However, few studies have

Q-1 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Formation damage is probable once the fluid below the water table. The CPT data pressures in a borehole exceed the fracture (measured to a depth of 153') are extrapolated stress pressure of the formation. When this to approximately 300'. happens, borehole fluids will tend to flow under gravity and/or pumped pressure into the If the pore pressure is known, then it is formation along preferentially oriented planes possible to calculate the formation fracture of weakness. In most sediments, these planes stress gradient using the equation of Hubbert of weakness are lateral or horizontal (along and Willis (in Adams and Charrier, 1985) as the shear plane) rather than vertical (along the follows: compressive plane) (Adams and Charrier, 1985). However, vertical fractures are known P/Z (min, max) = (1/3 min, ½ max) in soft sediments in outcrop Formation (S,/Z + 2p/Z) damage is caused by flowing borehole fluids Where: displacing formation fluids and sediments. P = fracture pressure, psi Z = depth, feet Two key values are required to estimate S, = overburden at depth Z, psi whether formation damage is likely, the p = pore pressure, psi pressure of the borehole fluids at a given depth, and the fracture stress gradient of the Example: sediments. For this study, it is assumed that sediments at the SRS are not over-pressured for p = 43 psi, S, = 68 psi, Z=100 ft., (for example, due to hydraulic charging from then P = 78 psi minimum and 118 psi oil or gas) and are in iso-static equilibrium. If maximum the density or composition of the borehole fluids is known, or the weight of the fluids per The maximum and minimum calculated unit volume, then the hydrostatic pressure of fracture pressures from this equation are also the fluid per depth may be calculated, or read shown on Figure 1. It should be understood from prepared tables. The formation fracture that this equation is generally used for much gradient, by rule of thumb in Gulf Coastal deeper strata, however, the match between the Plain type sediments is approximately 1.0 CPT derived Effective Overburden pressure psi/ft (Adams and Charrier, 1985). However, and the minimum fracture pressure, is in the shallow sediments of the SRS, which interesting (the pore pressure, p, used in the are relatively less consolidated than deeper Hubbert and Willis equation is utilized from Gulf Coastal Plain sediments, (although they the CPT data). are of the same relative type and age) it is possible to calculate and extrapolate a stress The FMT tool measures formation fluid gradient based on data from the CPT and FMT pressure directly at discrete depths. These data information. are also shown on Figure 1. Compared to the normal hydrostatic curve (assuming Figure 1 is a graph showing the calculated freshwater) demonstrates that the measured pressure at depth for typical drilling mud and FMT pressures are higher and tend to parallel grout as defined in the Halliburton Cementing the normal hydrostatic curve. Tables. Overburden pressures, from the CPT tool from MWD-12 and hydrostatic pressures An assumption that the CPT Effective from the FMT tool are also shown. The FMT Overburden pressure, measured FMT MWD is a direct measure of total formation fluid 12 hydrostatic pressure and the minimum pressure. CPT overburden pressure are Formation Fracture pressures are equivalent is calculated as "total" which is a function of valid because the curves are similar on Figure depth, while "effective" overburden pressures 1 (the CPT Effective Overburden pressure and consider the effects of saturated sediments the minimum Fracture Pressure curves are

Q-2 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606 measured to 153' and extrapolated to Overburden, but demonstrate a divergence approximately 300'). This assumption is in Area C suggesting that measured intuitive for saturated sediments if the total formation pressures and calculated pressure at a given depth is a sum of the formation pressures also diverge at these lithologic and hydrostatic pressure at that depths. depth. Since the sediments are not over * the maximum Formation and Total pressured, the measured formation pressure Overburden Pressures are generally from the FMT and measured Effective greater than pressures anticipated in the Overburden Pressure from the CPT will be depth ranges evaluated, equivalent to the hydrostatic pressure of the + any pumping pressures from the surface formation at a given depth. must be added to the hydraulic pressures to estimate subsurface pressure effects. Results and Conclusions A review of the graph demonstrates that: Based on these observation, it is possible for drilling operation to hydraulically fracture * calculated overburden pressures from the typical unconsolidated sediments when grout CPT and the minimum fracture pressures and mud weights exceed the CPT measured from the Hubbert and Willis equation Effective Overburden Pressure or the generally agree, and are equivalent with calculated Minimum Formation Fracture the FMT derived pressures, Pressure. It may be worthwhile, in areas to be * the CPT Total Overburden and Effective evaluated using monitoring wells requiring Overburden curves diverge at the water casing, to obtain CPT derived data formation table, pressure data, and perform a hydraulic * the hydrostatic pressure from the 13.2 fracture potential analysis. Key formations, lb./gal. grout exceeds the Total Effective such as those mentioned earlier, may be Overburden curve the at approximately 90 damaged by excessive mud and/or grout feet (Area A) suggesting the possibility of weight induced hydraulic fracturing. hydraulic fracturing in sediments at this depth, References + the 10 lb./gal. mud weight exceeds the Adams, N. J. and Charrier, T., 1985, Drilling CPT Effective Overburden and minimum Engineering, PennWell Books, Tulsa, 960 p. Field Data Handbook, DowelI-Schlumberger, Fracture Pressure a approximately 240 Houston, TX feet, suggesting the possibility of hydraulic fracturing at this depth (Area Halliburton Cementing Tables, 1981, Haliburton B), Services Co., Duncan, OK * the FMT pressures are essentially equivalent to the extrapolated minimum Fracture Pressure and CPT Effective

Q-3 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

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Q-4 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Bibliography

Selected references from the SRS Generic Safety Analysis Report

Aadland R. K., and Bledsoe, H. W., 1990b, Amick, D.R., et.al. Paleoliquefaction Features "Hydrostratigraphy of the Coastal Plain sequence, Along the Atlantic Seaboard. NUREG/CR-5613, Savannah River Site (SRS), South Carolina": GSA U.S. Nuclear Regulatory Commission, Abstracts with Programs, v. 22, no. 7. Washington, DC, 1990. Aadland, R. K., 1997, Tertiary Geology of A/M Anderson, E. E. "The Seismotectonics of the Area Savannah River Site, South Carolina, WSRC Savannah River Site: The Results of a Detailed RP-97-0505, Rev 1. Westinghouse Savannah River Gravity Survey". M.Sc. Thesis, University of Company, Aiken SC 298098, 60 p. South Carolina, Columbia, SC, 246p. 1990. Aadland, R. K., and Bledsoe, H. W., 1990a, ASCE. Technical Engineering and Design Guides Classification of hydrostratigraphic units at the Adapted from the US Army Corps of Engineers, Savannah River Site, South Carolina: USDOE No. 9, Settlement Analysis American Society of Report, WSRC-RP-90-987, Westinghouse Civil Engineers Press, New York, New York, Savannah River Co., Westinghouse Savannah 1994. River Laboratory, Aiken, SC 29808, 15 p. ASTM. Laboratory Compaction Characteristics of Aadland, R. K., et al. Significance of Soft Zone Soil Using Modified Effort. ASTM D1557-91, Sediments at the Savannah River Site (U), American Society for Testing and Materials, Historical Review of Significant Investigations and Conshohocken, PA, 1999. Current Understanding of Soft Zone Origin, Extent Aucott, W. R., and Speiran, G. K., 1985a, "Ground and Stability. WSRC-TR-99-4083, Rev. 0, water flow in the Coastal Plain aquifers of South Savannah River Company, Westinghouse Carolina": Journal of Ground Water, v. 23, no. 6, September 1999. p. 736-745. Aadland, R. K., Smits, A. D., and Thayer, P. A., Aucott, W. R., Davis, M. E., and Speiran, G. K., 1992a, Geology and hydrostratigraphyof the A/M 1987, Geohydrologic firamework of the Coastal Area, Savannah River Site (SRS), South Carolina Plain aquifers of South Carolina: U.S. Geological (U): USDOE Report WSRC-RP-92-440, Survey Water-Resources Investigations Report 85 Westinghouse Savannah River Company, 4271. Savannah River Site, Aiken, SC 29808, 104 p. Barstow, N.L., et.al. An Approach to Seismic Aadland, R. K., WSRC-RP-97-0505, Rev. 1, Zonation for Siting Nuclear Electric Power of A/M Area Savannah River Tertiary Geology Generation Facilities in the Eastern United States: Site, South Carolina (U). NUREG/CR-1577. U.S. Nuclear Regulatory Aadland, R.K. Geology of A/M Area, Savannah Commission, 1981. River Site South Carolina. WSRC-RP-96-0505, Bates, R. L., and Jackson, J. A., 1980, eds. Rev. 0, Westinghouse Savannah River Company, Glossary of Geology: American Geological Aiken, SC, 1996. Institute, Falls Church, Va., 857 p. Aadland, R.K., Gellici, J. A. and P. A. Thayer, Baum, G.R., et.al. "Structural and Stratigraphic 1995, Hydrogeologic Framework of West-Central Framework for the Coastal Plain of North of South Carolina, South Carolina Department Carolina." Field Trip Guidebook for Carolina Resources Division, Natural Resources, Water Geological Society and Atlantic Coastal Plain Carolina, 200 p. Report 5, Columbia, South Geological Society. North Carolina Department of Amick, D. and Gelinas, R. "The Search for Natural Resources and Development, 1979. Evidence of Large Prehistoric Earthquakes along Beard, D. C., and Weyl, P. K., 1973, "Influence of for the Atlantic Seaboard." American Association texture on porosity and permeability of 1991. Vol. the Advancement of Science, February unconsolidated sand": American Association of 251, 1991. Petroleum Geologists Bulletin, 57, p. 349-369.

R-I Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Bechtel Corporation, 1982, Studies of postulated Bollinger, G.A., et.al. "Seismicity of the Millett Fault: Report prepared for Georgia Power Southeastern United States -- 1968 1986." Decade Company with Southern Company Services. of Geology. 1987.

Benedict, M., Cooke, J. B., Deere, D. U., Garrels, Bramlett, K.W. Geology of the R. M., Graham, R. M., and Wolman, A., 1969, Johnston-Edgefield Area, South Carolina, and its Permanent storage of radioactive separations Regional Implications. (M.S. Thesis). University process wastes in bedrock on the Savannah River of South Carolina, Columbia, SC, 1989. Plant Site: E. I. du Pont de Nemours and Co., Bramlett, K.W., Savannah River Laboratory, Aiken, SC 29801, 57 et.al. "The Belair Fault: A Cenozoic Reactivation p. Structure in the Eastern Piedmont." Geological Society of America Berkman, E. High Resolution Seismic Survey, Pen Bulletin. Vol. 93, 1982. Branch Fault, Savannah River Site, South Carolina. Brown, P.M., et.al. Structural WSRC-TR-91-38, Westinghouse Savannah River and Stratigraphic Framework, and Company, Aiken, SC, 1991. Spatial Distribution of Permeability of the Atlantic Coastal Plain, North Bledsoe, H.W., Aadland, R. K., and Sargent, K. A., Carolina to New York. U.S. Geological Survey 1990, Baseline Hydrogeologic Investigation Professional Paper 796, 1972. Summary Report. WSRC-RP-90-1010, Westinghouse Savannah River Company, Aiken, Chapelle, S. H. and Lovley, D. R., 1991, Competitive SC, 1990. exclusion of sulfate reduction by F(II) - reducing bacteria: A mechanism for Bobyarchick, A.R. "The Eastern Piedmont Fault producing discrete zones of high-iron groundwater, System and Its Relationship to Alleghanian Groundwater, Vol. 30 No. I, p. 29-36. Tectonics in the Southern Appalachians." Journal Chapman, W.L. of Geology. Vol. 89, 1981. and DiStefano, M.P. Savannah River Plant Seismic Survey, 1987-88. Research Bollinger, G.A. "Reinterpretation of the Intensity Report 1809-005-006-1-89, Conoco, Inc., Seismic Data for the 1886 Charleston, South Carolina Acquisition Section, 1989. Earthquake." Studies Related to the Charleston, Chowns, T.M., South Carolina, Earthquake of 1886--A Fritz, W.J., Latour, T.E., 1996, Preliminary Report. U.S. Geological Society "Investigation of Triassic Basin Sediments Savannah Professional Paper 1028, 1977. River Site. Final Report Prepared for Westinghouse Savannah River Co. Prime Contract Bollinger. G.A. "Seismicity of the Southeastern No. :DE-AC09-89SR 18035 ERDA Task #52. United States." Bulletin of the Seismological Christopher, Society of America. Vol. 63, No. 5, 1973. R. A., 1978, "Quantitative palynologic correlation of three Campanian and Maestrichtian Bollinger, G.A. "Specification of Source Zones, sections (Upper Cretaceous) from the Atlantic Recurrence Rates, Focal Depths, and Maximum Coastal Plain": Palynologv, v.2, p. 1-27. Magnitudes for Earthquakes Affecting the Clarke, Savannah River Site in South Carolina." U.S. J. S., Brooks, R., and Faye, R. E., 1985, Hydrogeologv Geological Survey Bulletin. No. 2017, 1992. of the Dublin and Midville aquifer sYstems of east-central Georgia: Georgia Bollinger, G.A. "Specification of Source Zones, Geological Survey Information Circular 74. Recurrence Rates, Focal Depths, and Maximum Magnitudes for Earthquakes Affecting the Clarke, J. S., Hacke, C. M., and Peck, M. F., 1990, Geology and ground-water Savannah River Site in South Carolina." U.S. resources of the coastal area of Georgia: Georgia Geological Survey Bulletin. No. 2017, 1992 Geological Survey Bulletin 113, 106 p. Bollinger, G.A., et.al. "An Analysis of Earthquake Focal Depths in the Southeastern United States." Colquhoun, D. J., J. M. Rine, M. P. Segall, M. P. Katuna, A. D. Geophysical Research Letters. Vol. 12, 1985. Cohen, and D. L. Siron, 1994, Sedimentology and Stratigraphy of the Upland Bollinger, G.A., et.al. "Seismicity of the Unit, Final. Prepared under SCUREF cooperation Southeastern United States: 1698-1986." Agreement with DOE, Task 119 Neotectonics of North America. Geological AA00900T.Columbia, South Carolina: University Society of America DNAG Map Vol. 1, 1991 of South Carolina, Geological Sciences Department, Earth Science and Resources Institute.

R-2 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Colquhoun, D. J., Oldham, R. W., Bishop, J. W., Constraints on the Tectonothermal Evolutions of and Howell, P. D., 1982, Up-dip delineation of the the Eastern Piedmont in South Carolina." Tertiary limestone aquifer: South Carolina Geological Society of America Bulletin. Vol. 97, Department of Geology, University of South 1986. Carolina, Columbia, SC, 29201 Daniels, D.L. "Geologic Interpretation of Colquhoun, D.J. and Steele, K.B. Geophysical Maps, Central Savannah River Area, Chronostratigraphy and Hydrostatigraphy of the South Carolina and Georgia." Geophysical Northwestern South Carolina Coastal Plain. Investigation Map GP-893, U.S. Geological Annual Cooperative Grant Agreement No. 13040 Survey, 1974. R-83-591, Project No. G868-05, Interim Technical Davis, G.J. The Southwestern extension of the Report to Water Resources Research Institute, Middleton-Lowndesville Cataclastic Zone in the Clemson University, Clemson, South Carolina, Greensboro, Georgia, Area and its Regional 1985. Implications (M. S. Thesis). University of Colquhoun, D.J., et.al. "Surface and Subsurface Georgia, Athens, Georgia, 1980. Structure and Aquifers of the South Stratigraphy, Dennehy, K.F., et.al. "Geohydrology of the ISBN Carolina Coastal Plain." SCDHEC Report Defense Waste Processing Facility and Vicinity, 0-9613154-0-7, 1983. Savannah River Plant, South Carolina." U.S. Cook, F.A., et.al. "COCORP Seismic Profiling of Geological Survey Water Resources Investigation, the Appalachian Orogen Beneath the Coastal Plain WRI 88-4221, 1988. of Georgia." Geological Society of America Dennis, A.J. "Is the Central Piedmont Suture a Bulletin. Vol. 92, No. 10, 1981. Low-Angle Normal Fault?" Geology. Vol. 19, Cook, F.A., et.al. "Thin-skinned Tectonics in the 1991 Crystalline Southern Appalachians: COCORP Dennis, A.J., Maher Jr., H. D., Mauldin, J.C., of the Blue Ridge and Seismic Reflection Profiling Shervais, J.W., 1996, "Repeated Phanerozoic Vol. 7, 1979. Piedmont." Geology. Reactivation of a Southern Appalachian Fault Zone Cooke, C.W. "Geology of the Coastal Plain of Beneath the Up-Dip Coastal Plain of South South Carolina." U.S. Geological Survey Bulletin. Carolina. Report submitted for SCURF Task 170. No. 867, 1936. Dept. of the Navy. Soil Mechanics, NAVFAC Coruh, C., et.al. "Results from Regional Vibroseis DM-7.01, Washington D. C., September 1986. Site Profiling: Appalachian Ultradeep Core Hole Dewy, J. W., "Relocation of instrumentally Study." Geophysical Journal of the Royal recorded pre-1974 earthquakes in the South Astronomical Society. Vol. 89, 1987. Carolina region". In Gohn, G.S. (ed.), Studies Coruh, C., et.al. "Seismogenic Structures in the Related to the Charleston, South Carolina Central Virginia Seismic Zone." Geology. Vol. Earthquake of 1886 - Techtonics and Seismicity, 16, 1988. U.S. Geological Survey Professional Paper 1313, ql-q9, 1983. Cox, J. and Talwani, P. "Paleoseismic Studies in the 1886 Charleston Earthquake Dillon, W.P. and Popenoe, P. "The Blake Plateau Meizoseismal Area." Geological Society of Basin and Carolina Trough." The Geology of America, Abstracts with Programs. No. 16, 1983. North America. V 1-2, The Atlantic Continental Margin. DNAG Publication, Geological Society of Cumbest, R.J., et.al. "Gravity and Magnetic America, Boulder, CO, 1988. Modeling of the Dunbarton Triassic Basin, South Carolina." Southeastern Geology. Vol. 33, No. 1, Dobry, R., et.al. Predication of Pore Water 1992. Pressure Buildup and Liquefaction of Sands During Earthquakes by the Cyclic Strain Method. Cumbest, R.J., Stephenson, D.E., Wyatt, D.E., National Bureau of Standards Building Science Maryak, M. "Basement Surface Faulting for Series 138, 1982. Savannah River Site and Vicinity" WSRC-TR-98 00346. 1998. Domoracki, W.J. A "Geophysical Investigation of Geologic Structure and Regional Tectonic Setting Dallmeyer, R.D., et.al. "Character of the at the Savannah River Site, South Carolina". PhD Alleghanian Orogeny in the Southern Dissertation, Virginia Polytechnic Institute, Appalachians: Part II, Geochronological Blacksburg VA. 1995.

R-3 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Domoracki, W.J., et.al. "Seismotectonic Structures North Carolina: 1983 Guidebook for the Carolinas. Along the Savannah River Corridor, South Geological Society, North Carolina Division of Carolina, USA." Journal of Geodynamics. 1997. Land Resources, Article 11, 1983. Dutton, C. E. The Charleston Earthquake of Fullagar, P.D. and Odom, A.L. "Geochronology of August 31, 1886. U.S. Geological Survey, 1890. Precambrian Gneisses in the Blue Ridge Province of Northwestern North Carolina and Adjacent Dutton, C.E. "The Charleston Earthquake of Parts of Virginia and Tennessee." Geological August 31, 1886." U.S. Geological Survey Annual Society of America Bulletin. Vol. 84, 1973. Report 1887-1888. Government Printing Office, Washington, DC, 1889. Fullagar, P.D., et.al. "1200 m.y.-Old Gneisses in the Blue Ridge Province of North Evans, E. K. and Parizek, R. R., 1991, and South Carolina." Southeastern Geology. Characterization of hydraulic conductivity Vol. 20, 1979. heterogeneity in Tertiary sediments within the General Design Criteria. DOE Order 6430.IA, General Separations Area, Savannah River Site, U.S. Department of Energy, Washington, DC, South Carolina: Department of Geosciences, 1989. Pennsylvania State University, Pa., 157 p. GeoTrans, Inc., 1988, Characterizationof ground Facility Safety. DOE Order 420.1, U.S. water flow and transport in the General Department of Energy, Washington, DC, 1995. SeparationsArea, Savannah River Plant: Effects of closure options on groundwater flow at the Fallaw, W. C. and Price, V., 1992, Outline of F-Area seepage basins. Stratigraphy at the Savannah River Site: In Fallaw, W. C., and Price, Van, eds., 1992, Carolina Glover, L., Ill, et.al. "Diachronous Paleozoic Geological Society Field Trip Guidebook, Nov. 13 Mylonites and Structural Heredity of 15, 1992, Geological Investigation of the Central Triassic-Jurassic Basins in Virginia." Geological Savannah River Area, South Carolina and Georgia: Society of America Abstracts with Programs. Vol. US Dept of Energy and SC Geological Survey, P. 12, 1980. CGS-92-B-1 1-1-33. Gohn, G.S. "Late Mesozoic and Early Cretaceous Fallaw, W.C. and Price, Van. "Stratigraphy of the Geology of the Atlantic Coastal Plain: North Savannah River Site and Vicinity." Southeastern Carolina to Florida." The Geology of North Geology. Vol. 35, No. 1, 1995. America. Vol. 1-2, The Atlantic Continental Margin, pp. 107-130, DNAG Fallaw, W.C., et.al. "Effects of Varying Degrees Publication, Geological Society of America, of Marine Influence on Tertiary Sediments in Boulder, CO., 1988 Southwestern South Carolina." Geological Society of America Abstracts with Programs. Vol. 22, No Gohn, G.S. Studies Related to the Charleston 7, 1990. Earthquake of 1886: Tectonics and Seismicity. U.S. Geological Farrar, S.S. "Tectonic Evolution of the Survey Professional Paper 1313, 1983. Eastern-Most Piedmont, North Carolina." Geological Society of America Bulletin. Vol. 96, Gohn, G.S., et.al. "Field Studies of Earthquakes 1985. Induced Liquefaction-Flowage Features in the Charleston, Faye, R.E. and Prowell, D.C. Effects of Late South Carolina, Area Preliminary Report". Cretaceous and Cenozoic Faulting on the Geology U.S. Geological Survey Open-File Report 84-670, 1984. and Hydrology of the Coastal Plain Near the Savannah River, Georgia and South Carolina. U.S. Goldsmith, R., et.al. "Geologic Map of the Geological Survey Open File Report 82-156, 1982. Charlotte lx2 Quadrangle, North Carolina and South Carolina." Fetter, C. W., 1986, Applied Hydrogeology (2nd U.S. Geological Survey Miscellaneous Edition) Merrill Publishing Company, Columbus, Investigations Series Map 1-125 1-E, Scale 1:250,000, 1988. Oh. Gore, P.J.W. Fullagar, P.D. and Bartholomew, M.J. "Depositional Framework of a Triassic Rift Basin: The Durham "Rubidium-Strontium Ages of the Watauga River and Sanford Sub-basins of Cranberry, and Crossing Knob Gneisses, the Deep River Basin, North Carolina." Society of Economic Northwestern North Carolina." Geological Paleontologists and Mineralogists investigations in the Blue Ridge of Northwestern Field Guidebook. Third Annual Midyear Meeting, Raleigh, NC, 1986.

R-4 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Griffin, V.S., Jr. "Geology of the Abbeville East, Hatcher, R.D., Jr. "Tectonics of the Western Abbeville West, Latimer and Lowndesville Piedmont and Blue Ridge, Southern Appalachians: Quadrangles, South Carolina." South Carolina Review and Speculation." American Journal of Geological Survey MS-24. 1979. Science. Vol. 278, 1978. Grow, J.A., et.al. "Structure and Evolution of Hatcher, R.D., Jr. and Butler, J.R. Guidebook for Baltimore Canyon Trough." The Geology of North Southern Appalachian Field Trip in the Carolinas, America. Vol. I-1, The Atlantic Continental Tennessee, and Northeastern Georgia. Margin. DNAG Publication, Geological Society of International Geologic Correlation Program Project America, Boulder, CO, 1988. 27, University of North Carolina, Chapel Hill, NC, 1979. Grubb, H. F., 1986, Gulf Coast regional aquifer system analysis - A Mississippi perspective: U. S. Hatcher, R.D., Jr. and Edelman, S.H. Geological Survey Water-Resources Investigations "Macro-Scale Partitioning in the Southern and Report 86-4162, 22 p. Central Appalachians: Thrusting and Strike-Slip as Products of Alleghanian Collision." Geological Guidelines for Use of Probabilistic Seismic Hazard Society of America Abstracts with Programs. Vol. Curves at Department of Energy Sites. 19, 1987. DOE-STD-1024, U.S. Department of Energy, Washington, DC, December 1992. Hatcher, R.D., Jr. and Goldberg, S.A. "The Blue Ridge Geologic Province." The Geology of the Gutierrez, B.J. (1999). Letter from the DOE to to Carolinas. Carolina Geological Society 50th L.A. Salomone and F. Loceff, on "Revised Anniversary Volume, 199 1. Envelope of the Site Specific PC-3 Surface Ground Motion", September 9, 1999. Hatcher, R.D., Jr., et.al. "Eastern Piedmont Fault System: Speculations on its Extent." Geology. Hall, M.H. "Heavy Mineral Provinence of Triassic Vol. 5, 1977. Dunbarton Basin Deposits, South Carolina". MSc. Thesis, University of North Carolina Wilmington, Hatcher, R.D., Jr., et.al. "Geometric and Time Wilmington, NC. 1997. Relations of Thrusts in the Crystalline Southern Appalachians." Geometry and Mechanisms of Hanson, K.L., et.al. "Applications of Quaternary Appalachian Thrusting, with Special Reference to Stratigraphic, Soil-Geomorphic, and Quantitative the Appalachians. Geological Society of America Geomorphic Analyses to the Evaluation of Special Paper 222, 1988. Tectonic Activity and Landscape Evolution in the Upper Coastal Plain, South Carolina." Hatcher, R.D., Jr., et.al. "Tectonic Map of the U.S. Proceedings, 4th DOE Natural Phenomena Hazards Appalachian, Plate 1, the Applachian-Ouachita Mitigation Conference. Vol. 2, Atlanta, Georgia, Orogen in the United States." The Geology of 1993. North America. Vol. F-2. Geological Society of America, Boulder, CO, 1990. Hasek, M. J. Settlement of H-Area Waste Storage Tanks and Structures (U), K-ESR-H-0001 1, Rev. Heller, P.L., et.al. "Episodic Post-Rift Subsidence 0.0, October 1999. of the United States Atlantic Margin." Geological Society of America Bulletin. Vol. 93, No. 5, 1982. Hatcher, R.D., et.al. "The Smokies Foothills Duplex and Possible Significance of the Guess Herrick, S. M., and Vorhis, R. C., 1963, Subsurface Creek Fault, A Corollary to the Mapping of King geology of the Georgia Coastal Plain: Georgia and Neuman." Geological Society of America Department of Natural Resources, Division of Abstracts with Programs. Vol. 18, 1986a. Mines, Mining, and Geology Information Circular 25, 80 p. Hatcher, R.D., et.al. Continent-Ocean Transect E5 Cumberland Plateau (North American Craton) to Herrmann, R.B. "Surface-Wave Studies of Some Blake Plateau Basin. The Decade of North South Carolina Earthquakes." Bulletin of the American Geology Project, Geological Society of Seismological Society of America. Vol. 76, No. 1, America, Boulder, CO, 1994 1986. Hatcher, R.D., Jr. "Developmental Model for the Heyn, T. "Geology of the Hinge Zone of the Southern Appalachians." Geological Society of Sauratown Mountains Anticlinorium, North America Bulletin. Vol. 83, 1972. Carolina: Structure of the Sauratown Mountains Window, North Carolina." Carolina Geological Society Guidebook. 1988.

R-5 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Hooper, R.J. and Hatcher, R.D., Jr. "The Pine King, P.B. "A Geologic Cross Section Across the Mountain Terrane, a Complex Window in the Southern Appalachians, An Outline of the Geology Georgia and Alabama Piedmont-Evidence from the in the Segment in Tennessee, North Carolina, and Eastern Termination." Geology. Vol. 16, 1988. South Carolina." Guides to Southeastern Geology. Geological Society of America Hopson, J.L., et.al. "Geology of the Eastern Blue Annual Meeting, 1955. Ridge of Northeast Georgia and the Adjacent Carolinas." Georgia Geological Society King, P.B. Systematic Pattern of Triassic Dikes in Guidebook. Vol. 9, 1989. the Appalachian Region, Second Report. U.S. Geological Survey Professional Hopson, J.R. "Structure, Stratigraphy, and Paper 759-D, 1971 Petrogenesis of the Lake Burton Mafic-Ultramafic King, P.B., et.al. 1968, Geology of the Great Complex." Georgia Geological Society Smoky Mountains National Park, Tennessee and Guidebook. Vol. 9, 1989. North Carolina. U.S. Geological Survey Professional Paper 587. Horton, J.W., Jr. "Shear Zone Between the Inner Piedmont and Kings Mountain Belts in the Klitgord, K.D. and Schouten, H. "Plate Carolinas." Geology. Vol. 9, 1981. Kinematics of the Central Atlantic." The Geology of North America. Horton, J.W., Jr. and McConnell, K.I. "The Vol. M, The Western North Atlantic Region. Western Piedmont." The Geology of the DNAG Publication, Geological Society of America, Boulder, CO, 1986. Carolinas. Carolina Geological Society 50th Anniversary Volume, 1991. Klitgord, K.D., et.al. "US Atlantic Continental Margin: Structural and Tectonic Housner, G.W. Earthquake Criteria for the Framework." The Geology of North America. Savannah River Plant. DPE-2383, E.I. du Pont de V 1-2, The Atlantic Continental Nemours and Company, Savannah River Plant, Margin. DNAG Publication, Geological Aiken, SC, 1968. Society of America, Boulder, CO, 1988. Huddlestun, P.F. and Hetrick, J.H. "Stratigraphy Koester, J.P. of the Tobacco Road Sand - A New Formation." and Franklin, A.G. Current Methodologies for Assessing the Georgia Geologic Survey. Bulletin 93, 1978. Potential for Earthquake-Induced Liquefaction in Soils. Hutchinson, D.R. and Klitgord, K.D. "Evolution NUREG/CR-430, U.S. Nuclear Regulatory of Rift Basins on the Continental Margin Off Commission, Washington, DC, 1985. Southern New England: Triassic-Jurassic Rifting: Krause, R. E. North America and Africa." American Association and Randolph, R. B., 1989, Hydrology of the Floridan aquifer system of Petroleum Geologists Memoir, 1986. in southeast Georgia and adjacent parts of Florida Hydrogeologic Characterization of the MWMF and South Carolina: U. S. Geological Survey (Mixed Waste Management Facility), SRS. Professional Paper 1403-D, 64 p. WSRC-RP-92-837, Westinghouse Savannah River Krause, R. E., 1982, Company, Aiken, SC, 1992 Digital model evaluation of the predevelot-ment flow'system of the Tertiary Kanter, L.R. Tectonic Interpretation of Stable limestone aquifer, southeast Georgia, northeast Continental Crust in: The Earthquakes of Stable Florida, and southern South Carolina: U. S. Continental Regions. Electric Power Research Geological Survey Water-Resources Investigations Institute, Palo Alto, CA, 1994. Report 82-173, 27 p.

Keen, C.E. and Haworth, R.T. "DNAG Transect Lahr, J.C., "HYPOELLIPSE: a computer program D-3: Rifted Continental Margin Off Nova Scotia: for determining local earthquake hypocentral Offshore Eastern Canada." Geological Society of parameters, magnitude, and first motion pattern." America, Centennial Continent/Ocean Transect #4. U.S. Geological Survey Open-File report 84-519, Boulder, CO, 1985. 35p., 1984.

Kimball, J.K. "The Use of Site Dependent Latour, T.E., Roden, M.F., Vanko, D.A., Whitney, Spectra." Proceedings of the U.S. Geological J.A. "Crystalline Basement Core - Savannah River Survey Workshop on Site Specific Effects of Soil Site. Final Report". ERDA Task 53, 303p, 1995. and Rock on Ground Motions and the Implications Lee, R.C. for Earthquake-Resistant Design. U.S. Geological Investigations of Nonlinear Dynamic Soil Properties at the Savannah Survey Open File Report 83-845, 1983. River Site.

R-6 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

WSRC-TR-96-0062, Rev. 0, Westinghouse Society Field Trip Guidebook. South Carolina Savannah River Company, Aiken, SC, March 1996 Geological Survey, 1978. Leutgert et.al. "Crystal Structure Beneath the Maher, H.D., et.al. "40Ar/39Ar Constraints on Atlantic Coast Plain of South Carolina." Chronology of Augusta Fault Zone Movement and Seismological Research Letters. Vol. 65, No. 2, Late Alleghanian Extension, Southern Appalachian 1994. Piedmont, South Carolina and Georgia." American Journal of Science. Vol. 294, 1994. Lewis, M. R., Arango, I., Kimball, J. K. and T. E. Ross. "Liquefaction Resistance of Old Sand Maher, H.D., et.al. "The Eastern Piedmont of Deposits," Proceedings of the XI Panamerican South Carolina." The Geology of the Carolinas. Conference on Soil Mechanics and Geotechnical University of Tennessee Press, Knoxville, 1991. Engineering. Foz do lguassu, Brazil, August 1999. Maher, H.D., Jr. "Kinematic History of Mylonitic Li, W. T. Settlement of Defense Waste Processing Rocks from the Augusta Fault Zone, South Facility (U), K-ESR-S-00003, Rev. 0, September Carolina and Georgia." American Journal of 1999. Science. Vol. 287, 1987. Lindholm, R.C. "Triassic-Jurassic Faulting in Maher, H.D., Jr. Stratigraphy, Metamorphism, and Eastern Northern America - A Model Based on Structure of the Kiokee and Belair Belts Near Pre-Triassic Structures." Geology. Vol. 6, 1978. Augusta, Georgia (MS Thesis). University of South Carolina, Columbia, SC, 1979. Logan, W. R. and Euler, G. M., 1989, Geology and ground-water resources of Allendale, Bamberg, Maher, H.D., Jr., et.al. "Magmatic Softening in the and Barnwell Counties and part of Aiken County, Orogenic Hinterlands Southern Appalachian South Carolina: Water Resources Commission Piedmont, Georgia." Geological Society of Report 155, 113 p. America Abstracts with Programs. Vol. 24, No. 2, 1992. Lohman, S. W., et al, 1972, Definitions of selected groundwater terms - revisions and conceptual Manspeizer, W., et.al. "Separation of Morrocco refinements: U. S. Geological Survey Water and Eastern North America: A Triassic-Liassic Supply Paper 1988, 21 p. Stratigraphic Record." Geological Society of America Bulletin. Vol. 89, 1978. Long, L.T. "The Carolina Slate Belt-Evidence of a Continental Rift Zone." Geology. Vol. 7, 1979. Marine, I. Geohydrology of the Buried Triassic Basin at the Savannah River Plant Groundwater. Long, L.T. and Chapman, J.W., Jr. "Bouguer Vol. 2, 1974a. Gravity Map of the Summerville-Charleston, South Carolina Epicentral Zone and Tectonic Marine, I. W., 1966, "Hydraulic correlation of Implications." Studies Related to the Charleston, fracture zones in buried crystalline rock at the South Carolina Earthquake of 1886--A Preliminary Savannah River Plant near Aiken, South Carolina": Report. U.S. Geological Survey Professional Paper Geological Survey Research 1966, Chapter D, U.S. 1028, 1977. Geological Survey Professional Paper 550-D, p. D223-D227. Luetgert, J.H., H.M. Benz, and S. Madabhushi, "Crustal Structure beneath the Atlantic coastal Marine, I. W., 1967a, "The permeability of plain of South Carolina." Seismological Research fractured crystalline rock at the Savannah River Letters, vol 30, no. 7, 180-191, 1994 Plant near Aiken, South Carolina": Geological Survey Research 1967, Chapter B, U.S. Geological "Fault Plane Madabhushi, S. and Talwani, P. Survey Professional Paper 575-B, p. B203-B211. Solution and Relocations of Recent Earthquakes in Middleton Place Summerville Seismic Zone Near Marine, I. W.,1967b, "The use of tracer test to Charleston South Carolina." Bulletin of the verify an estimate of groundwater velocity in Seismological Society of America. Vol. 83, No. 5, fractured crystalline rock at the Savannah River 1993. Plant near Aiken, South Carolina": in Isotope Techniques in the Hydrologic Cycle: Geophysical Maher, H.D. "Stratigraphy and Structure of the Monograph Series, v. 11, ed., G. E. Stout, Belair and Kiokee Belts near Augusta, Georgia, Washington, DC, American Geophysical Union, p. Geological Investigations of the Eastern Piedmont, 171-178. Southern Appalachians." Carolina Geological

R-7 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Marine, 1.W. "Geohydrology of Buried Triassic Mitwede, S.K., et.al. "Major Chemical Basin at Savannah River Plant, South Carolina." Characteristics of the Hammett Grove American Association of Petroleum Geologists Meta-igneous Suite, Northeastern South Carolina." Bulletin. Vol. 58, 1974b. Southeastern Geology. Vol. 28, No. 1, 1987. Marine. I.W. and Siple, G.E. "Buried Triassic Moos, D. and Zoback, M.D. In Situ Stress Basin in the Central Savannah River Area, South Measurements in the NPR Hole, Savannah River Carolina and Georgia." Geological Society of Site, South Carolina: Final Report to Westinghouse America Bulletin. Vol. 85, 1974. Savannah River Co., Vol. 1, Results and Interpretations. Subcontract AA00925P, Martin, G.R., et.al. "Fundamentals of Liquefaction Science Applications International Corporation, Under Cyclic Loading." Journal of the Augusta, GA, 1992. Geotechnical Engineering Division. Proceedings Paper 11284, ASCE, Vol. 101, No. 5, May 1975. National Center for Earthquake Engineering Research. Proceeding Mauldin, J., Shervais, J.W., Dennis, A.J., 1996, of the NCEER Workshop on Evaluation of "Petrology and Geochemistry of Metavolcanic Liquefaction Resistance of Soils. Technical Reprot NCEER-97-0022, Rocks from a Neoproterozoic Volcanic Arc, Buffalo, NY, December 31, 1997. Savannah River Site, South Carolina". Report submitted for SCURF Task 170. National Earthquake Hazards Reduction Program (NEHRP) Recommended McBride, J.H. "Constraints on the Structure and Provisions for Seismic Regulations Tectonic Development of the Early Mesozoic for New Buildings and Other Structures. Building Seismic Safety Council, part South Georgia Rift, Southeastern United States; I Provisions (FEMA 302). Seismic Reflection Data Processing and Interpretation." Tectonics. Vol. 10, No. 5, 1991. Natural Phenomena Hazards Assessment Criteria. DOE-STD-1023-95, McConnell, K.I. "Geology of the Sauratown U.S. Department of Energy, Washington DC, 1995. Mountains Anticlinorium; Vienna and Pinnacle 7.5 Minute Quadrangles: Structure of the Sauratown Natural Phenomena Hazards Design and Mountains Window, North Carolina." Carolina Evaluation Criteria for Department of Energy Geological Society Guidebook. 1988. Facilities. DOE-STD- 1020-94, U.S. Department of Energy, Washington, Meisler, H., 1980, Plan of study for the northern DC, April 1994. Atlantic Coastal Plain regional aquifer s.ystem Natural Phenomena Hazards Performance analvsis: U.S. Geological Survey Water-Resources Categorization Criteria for Structures, Systems, and Investigations Report 80-16, 27 p. Components. DOE-STD-1 021-93, U.S. Department Miller, J. A, and Renken, R. A., 1988, of Energy Washington, DC, 1993. Nomenclature of regional hydrogeologic units of NCEER, Youd, T. L. and I. M. Idriss. Proceeding the Southeastern Coastal Plain aquifer system: U. of the NCEER Workshop on Evaluation of S. Geological Survey, Water Resources Liquefaction Resistance of Soils. Technical Reprot Investigations Report 87-4202, 21 p. NCEER-97-0022, Buffalo, NY, December 31, 1997. Miller, J. A., 1986, Hvdrogeologic firamework of the Floridan aquifer system in Florida and in Nelson, A.E., et.al. "Generalized Tectonic Map of parts of Georgia, Alabama, and South Carolina: the Greenville lx2 Quadrangle, Georgia, South U.S. Geological Survey Professional Paper 1403 Carolina, and North Carolina." U.S. Geological B, 91 p. Survey Miscellaneous Field Studies Map MF-1898, Mitchell, J. K. "Practical Problems from Scale 1:250,000, 1987. Surprising Soil Behavior," The 20"' Terzaghi Nelson, K.D., et.al. "New COCORP Profiling in Lecture, Journal of Geotechnical Engineering, Vol. the Southeastern United States: Part I: Late 112, No. 3, American Society of Civil Engineers, Palcozoic Suture and Mesozoic Rift Basin." March 1986. Geology. Vol. 13, 1985. Mitchell, J. K. and Solymar, Z. V. "Time Neuman, R.B. and Nelson, W.H. Geology of the Dependent Strength Gain in Freshly Deposited or Western Great Smoky Mountains, Tennessee. U.S. Densified Sand," Journal of Geotehcnical Geological Survey Professional Paper 349-D, Engineering Division. Vol. 110, No. I1, American 1965. Society of Civil Engineers, November 1984.

R-8 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Noel, J.R., et.al. "Paleomagnetism and 40 Ar/39 Olsen, P.E., et.al. "Rift Basins of Early Mesozoic Ar Ages from the Carolina Slate Belt, North Age." The Geology of the Carolinas. University Carolina: Implications for Terrane Amalgamation." of Tennessee Press, Knoxville, 1991. Geology. Vol. 16, 1988. Ou, G.B. and Herrmann, R.B. "A Statistical Model Nystrom, P. G., and Willoughby, R. H., 1982, for Ground Motion Produced by Earthquakes at "Geological investigations related to the Local and Regional Distances." Bulletin of the stratigraphy in the kaolin mining district, Aiken Seismological Society of America. Vol. 80, No. 6, County, South Carolina": in, South Carolina 1990. Geological Survey, 1982 Carolina Geological Parsons, et.al. Bedrock Waste Storage Project, Society Field Trip Guidebook, 183 p. Triassic Basin Fault Probing Program Report. E. I. Nystrom, P. G., Jr., Willoughby, R. H. and Kite, L. du Pont de Nemours and Co., Savannah River E., 1986, "Cretaceous-Tertiary stratigraphy of the Plant, Aiken, SC, 1973. upper edge of the Coastal Plain between North Pen Branch Fault Basement Drilling. Augusta and Lexington South Carolina": in, Westinghouse Environmental and Geotechnical Carolina GeologicalSociety Field Trip Guidebook, Services, 1991. South Carolina Geological Survey. Petersen, T.A., et.al. "Structure of the Riddleville Stratigraphy of Nystrom, P.G., et.al. "Claibornian Basin from COCORP Seismic Data and the Savannah River Site and Surrounding Area, Implications for Reactivation Tectonics." Journal 1990, Savannah River Region: Transition Between of Geology. Vol. 92. 1984. the Gulf and Atlantic Coastal Plains." Proceedings of the Second Bald Head Island Conference on Phinney, R.A. and Roy-Chowdhury, K. Reflection Coastal Plains Geology. Hilton Head Island, Seismic Studies of Crustal Structure in the Eastern November 6-11, 1990. United States: Geophysical Framework of the Continental United States. Geological Society of Prowell, D.C. "The Geology O'Connor, B.J. and America Mem. 172, 1989. of the Belair Fault Zone and Basement Rocks of the Augusta, Georgia Area." Georgia Geological Poag, C.W. and Valentine, P.C. "Mesozoic and Society Guidebook 16. 1976. Cenozoic Stratigraphy of the US Atlantic Continental Shelf and Slope." The Geology of O'Connor, B.J. and Prowell, D.C. "The Geology North America. V 1-3, The Atlantic Continental of the Belair Fault Zone and Basement Rocks of Margin. DNAG Publication, Geological Society of the Augusta, Georgia Area." Georgia Geological America, Boulder, CO, 1988. Society Guidebook 16. 1976. Poland, J. F., Lofgren, B. E., and Riley, F. S., 1972, O'Connor, et.al. "Recently Discovered Faults in Glossary of selected terms useful in studies of the abstract, the Central Savannah River Area." mechanics of aquifer systems and land subsidence Vol. 32, Georgia Academy of Science Bulletin. due to fluid withdrawal: U. S. Geological Survey 1974. Water Supply Paper 2025, 9 p. Obermeier, S.F., et.al. "Geologic Evidence for Preliminary Report on Belair Exploratory Trench Recurrent Moderate to Large Earthquakes near No. 10-76 Near Augusta, Georgia. Open File Charleston, South Carolina." Science. Vol. 227, Report No. 77-411, U.S. Geological Survey, 1985. Atlanta, GA, 1977. Obermeier, S.F., et.al. Earthquake-lnduced Price, V., et.al. Pen Branch Fault Investigation Liquefaction Features in the Coastal Setting of Program Plan. ESS-SRL-89-395, 1989. South Carolina and in the Fluvial Setting of the New Madrid Seismic Zone. U.S. Geological Prowell, D. C., Christopher, R. A., Edwards, L. E., Survey Professional Paper No. 1504, 1990. Bybell, L. M., and Gill, H. E., 1985a, "Geologic section of the updip Coastal Plain from central Olsen, P.E. "On the Use of the Term Newark for Georgia to western South Carolina": USGS Rocks of Eastern North Triassic and Early Jurassic Miscellaneous Field Studies, Map MF-1737. America." Newsletters on Stratigraphy. Vol. 7, 1978. Prowell, D.C. "Cretaceous and Cenozoic Tectonism on the Atlantic Coastal Margin, the Olsen, P.E. and Schlische, R.W. "Unraveling the Geology of North America, the Atlantic Rules of Rift Basins." Geological Society of America Abstracts with Programs. Vol. 20, 1988.

R-9 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Continental Margin." Geological Society of Guidebook. South Carolina Geological Survey, America. Vol. 1-2, 1988. 1987 Prowell, D.C. Index of Faults of Cretaceous and Samson, S., et.al. "Biogeographical Significance Cenozoic Age in the Eastern United States. U.S. of Cambrian Trilobites from the Carolina Slate Geological Survey Miscellaneous Field Studies Belt." Geological Society of America Bulletin. Map MF-1269, 1983. Vol. 102, 1990.

Prowell, D.C. Preliminary Geologic Map of the Sawyer, D.S. "Thermal Evolution." The Geology Barnwell 30' x 60' Quadrangle, South Carolina of North America. Vol. 1-2, The Atlantic and Georgia. Open File Report 94-673, U.S. Continental Margin. DNAG Publication, Geological Survey, Atlanta, GA, 1994. Geological Society of America, Boulder, CO, 1988. Prowell, D.C. and O'Connor, B.J. "Belair Fault Zone: Evidence of Tertiary Fault Displacement in Schlische, R.W. and Olsen, P.E. "Quantitative Eastern Georgia." Geology. Vol. 6, 1978. Filling Model for Continental Extensional Basins with Application Prowell, D.C. and Obermeier, S.F. "Evidence of to the Early Mesozoic Rifts of Eastern North America." Journal Cenozoic Tectonism." The Geology of the of Geology. 1992. Carolinas. University of Tennessee Press, Knoxville, TN, 1991. Schmertmann, J. H. "The Mechanical Aging of Soils," The 25th Terzaghi Prowell, D.C., et.al. "The Ellenton Formation in Lecture, Journal of Geotechnical Engineering, South Carolina: A Revised Age Designation from Vol. 117, No. 9, , American Society of Civil Engineers, Cretaceous to Paleocene." U.S. Geological Survey September 1991. Bulletin. No. 1605-A, 1985. Schmertmann, Prowell, D.C., et.al. Preliminary Evidence for J. H. "Update on the Mechanical Aging of Soils," Holocene Movement Along the Belair Fault Zone for the symposium "Sobre Envejecimiento Near Augusta, Georgia. Open File Report 75-680, de Suelos," The Mexican Society of Soil Mechanics, U.S. Geological Survey, Atlanta, GA, 1976. Mexico City, August 1993. Scholz, Rast, N. and Kohles, K.M. "The Origin of the C.H. The Mechanics of Earthquakes and Faulting. Cambridge Ocoee Supergroup." American Journal of Science. University Press, 1990. V. 286, 1986. Secor, D.T., Jr. "Regional Overview, Anatomy of the Alleghanian Ratcliffe, N.E. "The Ramapo Fault System in New Orogeny as Seen from the York and Adjacent Northern New Jersey: A Case Piedmont of South Carolina and Georgia." Carolina Geological Society of Tectonic Heredity." Geological Society of Field Trip Guidebook. South Carolina Geological Survey, 1987. America Bulletin. Vol. 82, 1971. Secor, Reactor Site Criteria. 10 CFR 100, Washington, D.T., Jr. et.al. "Character of the Alleghanian DC, November 15, 1983. Orogeny in the Southern Appalachians, Part 1: Alleghanian Deformation in Reactor Site Criteria. 10 CFR 100, Washington, the Eastern Piedmont of South Carolina." DC, November 15, 1983 Geological Society of America Bulletin. Vol. 97, 1986a. Rozen, R.W. "The Middleton-Lowndesville Cataclastic Zone in the Elberton East Quadrangle, Secor, D.T., Jr., et.al. "Character of the Georgia." Geological Investigations of the Kings Alleghanian Orogeny in the Southern Mountain Belt and Adiacent Areas in the Appalachians: Part III, Regional Tectonic Carolinas. Carolina Geological Society Relations." Geological Society of America Guidebook. 1981. Bulletin. Vol. 97, 1986b. Sacks, P.E. and Dennis, A.J. "The Modoc Secor, D.T., Jr., et.al. "Confirmation of Carolina Zone-D 2 (Early Alleghanian) in the Eastern Slate Belt as an Exotic Terrane." Science. Appalachian Piedmont, South Carolina and Vol. 221. 1983. Georgia, Anatomy of the Alleghanian Orogeny as Seed, H.B. "Soil Liquefaction and Cyclic Mobility Seen from the Piedmont of South Carolina and Evaluation for Level Ground During Earthquakes." Georgia." Carolina Geological Society Field Trip Journal of Geotechnical Engineering Division.

R-10 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Vol. 105, No. 2, American Society of Civil and Overconsolidation," Geotechnique, Vol. 36, Engineers, February 1979. No. 3, 1986. Seed, R.B., Idriss, I. M. and 1. Arango. Smoot, J.P. "The Closed-Basin Hypothesis and Its "Evaluation of Liquefaction Potential Using Field Use in Facies Analysis of the Newark Performance Data." Journal of Geotechnical Supergroup." Proceedings of the Second U.S. Engineering Division. Volume 109, No. 3, Geological Survey Workshop on the Early American Society of Civil Engineers, 1983. Mesozoic Basins of the Eastern United States. U.S. Geological Survey Circular 946, 1985. Seismograph Services Corporation. Gravity and Magnetic Survey, Savannah River Plant, South Snipes, D. S., et.al. "The Pen Branch Fault: Carolina. Unpublished report prepared for E.l. du Documentation of Late Cretaceous-Tertiary Pont de Nemours and Co., Inc., Engineering Faulting in the Coastal Plain of South Carolina." Department, Wilmington, DE, 1972. Southeastern Geology. Vol. 33, No. 4, 1993. Sen, A.K. and Coruh, C. Removing Near-Surface Snoke, A.W. and Frost, B.R. "Exhumation of High Effects in Seismic Data: Application for Pressure Pelitic Schist, Lake Murray Spillway, Determination of Faults in the Coastal Plain South Carolina: Evidence for Crustal Extension Sediments. WSRC-TR-92-169, Westinghouse During Alleghanian Strike-Slip Faulting." Savannah River Company, Aiken, SC, 1992. American Journal of Science. Vol. 280, 1990. Sheridan, R.E. and Grow, J.A. "The Geology of Snoke, A.W., et.al. "Deformed Hercynian Granitic North America." The Atlantic Continental Margin. Rocks from the Piedmont of South Carolina." Vol. I-1 and 1-2, DNAG Publication, Geological American Journal of Science. Vol. 280, 1980. Society of America, Boulder, CO, 1988. Sohl, N. F., and Christopher, R. A., 1983, The Shervais, J.W., Mauldin, J., Dennis, A.J., 1996, Black Creek-Peedee formational contact (Upper "Petrology and Geochemistry of Neo- Proterzoic Cretaceous) in the Cape Fear River region of Arc Plutons beneath the Atlantic Coastal Plain: North Carolina: U. S. Geological Survey Savannah River Site, South Carolina". Report Professional Paper 1285, 37 p. Submitted for SCURF Task 170. Somerville, P.G., et.al. Comparison of Source Sibol, M.S. and Bollinger, G.A. Earthquake Scaling Relation of Eastern and Western North Catalog for the Southeastern United States, American Earthquakes. BSSA, 77, #2, 322-346. 1698-1989. Virginia Polytechnic Institute and 1987. State University Seismological Observatory Somerville, P.G., et.al. Comparison of Source Computer File, Blacksburg, VA, 1990. Scaling Relation of Eastern and Western North Sibol, M.S. and Bollinger, G.A. Earthquake American Earthquakes. BSSA, 77, #2, 322-346. Catalog for the Southeastern United States, 1987. 1698-1989. Virginia Polytechnic Institute and Steckler, M.S., et.al. "Subsidence and Basin State University Seismological Observatory Modeling at the U.S. Atlantic Passive Margin." Computer File, Blacksburg, VA, 1990. The Geology of North America. Vol. 1-2, The Sibson, R.H. "Earthquakes and Rock Deformation Atlantic Continental Margin. DNAG Publication, in Crustal Fault Zones." Annual Review of Earth Geological Society of America, Boulder, CO, Planet Sciences. Vol. 14, 1986. 1988. Sibson, R.H. "Frictional Constraints to Thrust, Steltenpohl, M.G. "Kinematics of the Towaliga, Wrench, and Normal Faults." Nature. Vol. 249, Bartletts Ferry, and Goat Rock Fault Zones, 1984. Alabama: The Late Paleozoic Dextral Shear System in the Southernmost Appalachians." Siple, G.E. "Geology and Ground Water of the Geology. Vol. 16, 1988. Savannah River Plant and Vicinity, South Carolina." Paper No. 1841, United States Stephenson, D.E. Savannah River Plant Geological Survey Water Supply. 1967. Earthquake. DPST-88-841, E.I. du Pont de Nemours and Co., Savannah River Laboratory, Skempton, A. W. "Standard Penetration Test Aiken, SC, August 1988. Procedures and the Effects in Sands of Overburden Pressure, Relative Density, Partical Size, Aging Stephenson, D.E. and Stieve, A. Structural Model of the Basement Based on Geophysical Data in the

R- 11 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

Central Savannah River Area, South Carolina and Savannah River Site and vicinity: WSRC-RP-92 Georgia. WSRC-TR-92-120, Westinghouse 450, Westinghouse Savannah River Company, Savannah River Company, Aiken, SC, 1992. Aiken, SC 29808, 96 p. Stephenson, D.E., et.al. "Savannah River Site Talwani, P. "Current Thoughts on the Cause of the Disaggregated Seismic Spectra." Fourth DOE Charleston, South Carolina Earthquakes." South Natural Phenomena Hazards Mitigation Carolina Geology. Vol. 29, 1985. Conference. U.S. Department of Energy, Talwani, Washington, DC, 1993. P. "Seismotectonics of the Charleston Region." Proceedings, National Conference on Stephenson, D.E., P. Talwani, J. Rawlins, Earthquake Engineering, 3r . Earthquake Savannah River Plant Earthquake of June 1985. Engineering Research Inst., Vol. 1, 1986. DPST-85-583, E.I. du Pont de Nemours & Co., Talwani, Savannah River Laboratory, Aiken, SC, 1985. P. The Woodstock Fault is Alive and Ticking Near Charleston, South Carolina. Stephenson, D.S. and Chapman, W.L. "Structure Submitted to the Bulletin of the Seismological Associated with the Buried Dunbarton Basin, Society of America, 1982. South Carolina from Recent Seismic Data." Talwani, Geological Society of America, Southeastern P. and Cox, S. "An Internally Consistent Section Abstracts with Programs. Vol. 20, 1988. Pattern of Seismicity Near Charleston, South Carolina." Geology. Vol. 10, 1985. Stieve, A.L. Pen Branch Fault Program: Interim Report on the High Resolution, Shallow Seismic Talwani, P. and Cox, S. "Paleoseismic Evidence for Reflection Surveys. WSRC-TR-91-30, Recurrence of Earthquakes near Charleston, Westinghouse Savannah River Company, Aiken, South Carolina." American Association for the SC, 1991b. Advancement of Science. Vol. 229, July 1985. Talwani, Stieve, A.L. and Stephenson, D.E. "Geophysical P., "Crustal Structure of South Carolina." Second Evidence for Post Late Cretaceous Reactivation of Technical Report to the U.S. Geological Survey, contract Basement Structures in the Central Savannah River #14-08-0001-14553, 1975. Area." Southeastern Geology. Vol. 35, No. 1, Talwani, P., B.K. Rastogi, and D.A. Stevenson, 1995. "Induced seismicity and earthquake prediction Stieve, A.L. et.al. Confirmatory Drilling Project studies in South Carolina." Tenth Technical Report Final Report. WSRC-RP-94-0136, Westinghouse to the U.S. Geological Survey, contract #14-08-0001-17670, Savannah River Company, Aiken, SC, 1994. 1980. Stieve, A.L. et.al. Confirmatory Drilling Proiect Talwani, P., et.al. Induced Seismicity and Final Report. WSRC-RP-94-0136, Westinghouse Earthquake Prediction Studies in South Carolina. Tenth Technical Savannah River Company, Aiken, SC, 1994. Report to the USGS, Contract 14-08-001 -17670.1980. Stieve, A.L., et.al. Pen Branch Fault Program: Consolidated Report on the Seismic Reflection Talwani, P., J. Rawlins, D. E. Stephenson. "The Surveys and the Shallow Drilling. Savannah River Plant, South Carolina, Earthquake WSRC-TR-91-87, Westinghouse Savannah River of June 9, 1985 and its Tectonic Setting." Earthquake Company, Aiken, SC, 1991 a. Notes. Vol. 56, No. 4, 1985. Stokoe, K.H., et.al. Correlation Study of Nonlinear Talwani, P.J., et.al. "The Savannah River Plant, Dynamic Soil Properties: Savannah River Site, South Carolina, Earthquake of June 9, 1985 and its Aiken, South Carolina. Rev. 0, File No. Tectonic Setting." Earthquake Notes. Vol. 56, No. 4, SRS-RF-CI)P-95, University of Texas at Austin, 1985. Department Civil Engineering. September 13, Tarr, A., P. Talwani, S. Rhea, D. Carver, and D. 1995. Amick. "Results of Recent South Carolina Stringfield, V. T., 1966, Artesian water in Tertiarv Seismological Studies." Bulletin of the limestone in the Southeastern States: U.S. Seismological Society of America. Vol. 71, 1981. Geological Survey Professional Paper 517, 226 p. Tarr, A.C., et.al. "Results of Recent South Strom, R. N., and Kaback, D. S., 1992, SRP Carolina Seismological Studies." Bulletin of the baseline h'drogeologic investigation: aquifer Seismological Society of America. Vol. 71, 1981. characterization,groundwater geochemistry of the

R-12 Carolina Geological Society, 2000 Annual Field Trip Guidebook WSRC-MS-2000-00606

URS/John A. Blume and Associates, Engineers. Stratigraphy of the A/M Area, Savannah River Update of Seismic Criteria for the Savannah River Site, South Carolina (U), WSRC-RP-97-0186, Rev. Plant, Vol. 1 of 2, Geotechnical. USR/JAB8144, 0,46 p. San Francisco, CA. Prepared for E.I. du Pont de Youd, T.L. "Liquefaction, Flow and Associated Nemours and Company as DPE-3699, Savannah Ground Failure." U.S. Geological Survey Circular. River Plant, Aiken, SC, 1982. No. 688, 1973. US Army Corps of Engineers (COE), Charleston Youd, T.L. and Hoose, S.N. "Liquefaction District. "Geologic Engineering Investigations, Susceptibility and Geologic Setting." Proceedings, Savannah River Plant", Volumes I and 2, 6th World Conference on Earthquake Engineering. Waterways Experimental Station, Vicksburg, MS, New Delhi, India, Vol. lII, 1977. 1952. Zoback, M.D. and Zoback, M.L. Tectonic Stress Vick, H.K., et.al. "Ordovician Docking of the Field of North America and Relative Plate Motions Carolina Slate Belt." Paleomagnetic Data: in Neotectonics of North America. Vol. 1, Tectonics. Vol. 6, 1987. Decade Map, Geological Society of America, Boulder, CO, Visvanathan, T.R., "Earthquakes in South 1991. Carolina, 1698-1975." South Carolina Geol. Surv. Zoback, M.L. and Zoback, M.D. "State of Stress Bull., vol. 40, 61p., 1980. in the Conterminous United States." Journal of Wait, R. L., and Davis, M. E., 1986, Configuration Geophysical Research. Vol. 85, 1980. and hydrology of the pre-Cretaceous rocks underlying the Southeastern Coastal Plain aquifer system: U.S. Geological Survey Water-Resources Investigations Report 86-4010, 1 sheet. Walton, W. C., 1970, Ground Water Resource Evaluation, McGraw-Hill Book Co., New York, N. Y., 664 p. Wang, W. Some Findings in Liquefaction. Water Conservancy and Hydroelectric Power Scientific Research Institute, Beijing, China, August 1979. Webster, D. S., Proctor, J. R., and Marine, I. W., 1970, Two-well tracer test in firactured ciystalline rock: U.S. Geological Survey Water-Supply Paper 1544-I. Wehr, F. and Glover, L., Ill. "Stratigraphy and Tectonics of the Virginia-North Carolina Blue Ridge: Evolution of a Late Proterozoic-Early Paleozoic Hinge Zone." Geological Society of America Bulletin. Vol. 96, 1985. Wentworth, C.M. and Mergener, K.M. "Regenerate Faults of the Southeastern United States." Studies Related to the Charleston, South Carolina, Earthquake of 1886, Tectonics and Seismicity. U.S. Geological Survey Professional Paper 1313, 1983. Winkler, C.D. and Howard, J.D. "Correlation of Tectonically Deformed Shorelines on the Southern Atlantic Coastal Plain." Geology. Vol. 5, 1977. Wyatt. D. E., Aadland, R. K., Cumbest, R. J., Stephenson, D. E., Syms, F. H., 1997 A/M Area Advanced Geological Study, Part 3 of 3, Geological Interpretation of the Structure and

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Notes

R-14 Notes Additional copies of this guidebook are available from the Department of Biology and Geology, University of South Carolina - Aiken, 471 University Parkway, Aiken, SC 29801-6309