Sir2005-5235.Pdf
A Cyclostratigraphic and Borehole- Geophysical Approach to Development of a Three-Dimensional Conceptual Hydrogeologic Model of the Karstic Biscayne Aquifer, Southeastern Florida
By Kevin J. Cunningham, Michael A. Wacker, Edward Robinson, Joann F. Dixon, and G. Lynn Wingard
Prepared in cooperation with the South Florida Water Management District
Scientific Investigations Report 2005-5235
U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey P. Patrick Leahy, Acting Director
U.S. Geological Survey, Reston, Virginia: 2006
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Suggested citation: Cunningham, K.J., Wacker, M.A., Robinson, Edward, Dixon, J.F., and Wingard, G.L., 2006, A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Three-Dimensional Conceptual Hydrogeologic Model of the Karstic Biscayne Aquifer, Southeastern Florida: U.S. Geological Survey Scientific Investigations Report 2005-5235, 69 p., plus CD. iii
Contents
Abstract...... 1 Introduction...... 2 Purpose and Scope...... 5 Description of Study Area...... 5 Previous Studies...... 5 Acknowledgments...... 7 Methods of Investigation...... 7 Drilling, Well Completion, Core Analysis, and Borehole-Geophysical Logging...... 7 Collection of Borehole-Fluid Flow Data...... 12 Molluscan and Benthic Foraminiferal Paleontology...... 12 Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer... 13 Lithostratigraphy...... 13 Molluscan Paleontology...... 13 Stratigraphic Age and Paleonenviroments from Test Corehole near S-3168...... 13 Stratigraphic Age and Paleoenvironments from Test Corehole near S-3170...... 13 Foraminiferal Paleontology...... 17 Lithofacies and Depositional Environments...... 17 Lithofacies...... 17 Depositional Environments...... 25 Middle Ramp...... 32 Platform Margin-to-Outer Platform...... 32 Open-Marine Platform Interior...... 32 Restricted Platform Interior, Brackish Platform Interior, and Freshwater Terrestrial...... 33 Cyclostratigraphy...... 33 Delineation of Cycles and Ideal Cycles...... 33 Cycle Hierarchy...... 33 Orders of Cycles...... 35 Hydrogeologic Framework for Model Representation of the Biscayne Aquifer...... 35 Previous Interpretations...... 35 Pore System of the Limestone of the Biscayne Aquifer...... 36 Pore Classes...... 36 Generalized Layering Scheme of Pore Classes...... 40 Altitudes and Thicknesses of Hydrogeologic Layers...... 43 Borehole-Fluid Flow...... 59 Ground-Water Flow and Pore System Evolution...... 59 Summary and Conclusions...... 62 References Cited...... 66 Appendix I: Geophysical Logs...... on CD Appendix II: Porosity and Permeability from Core Samples...... on CD Appendix III: Occurrence of Molluscan Taxa Identified in Selected Whole Core Samples...... on CD iv
Plates [on CD, back pocket]
1. Hydrogeologic section A-A’ showing cyclostratigraphy, lithology, and pore classes for the Biscayne aquifer in the Lake Belt area 2. Hydrogeologic section B-B’ showing cyclostratigraphy, lithology, and pore classes for the Biscayne aquifer in the Lake Belt area 3. Hydrogeologic sections C-C’ and D-D’ showing cyclostratigraphy, lithology, and pore classes for the Biscayne aquifer in the Lake Belt area 4. Hydrogeologic sections E-E’, F-F’, and G-G’ showing cyclostratigraphy, lithology, and pore classes for the Biscayne aquifer in the Lake Belt area
Figures
1-2. Maps showing: 1. Location of study area, Federal and State lands, and agricultural areas in southern Florida...... 3 2. Map of study area in Miami-Dade County showing location of major canals and levees, Northwest Well Field, Old South Dade Landfill, and test coreholes used in the study...... 4 3. Cross section showing relation of geologic and hydrogeologic units of the surficial aquifer system across central Miami-Dade County...... 6 4. Stratigraphic column showing correlation of ages, formations, stratigraphy, and hydrogeologic units of the Tamiami Formation, Fort Thompson Formation, and Miami Limestone from this and other studies...... 7 5-6. Photographs showing selected: 5. Pelecypoda from core samples...... 14-15 6. Gastropoda from core samples...... 16-17 7. Thin-section photomicrographs of foraminifera characteristic of foraminiferal biofacies 2-7...... 25 8. Conceptual hydrogeologic column for the northern part of the study area that includes ages, major depositional environments, ground-water flow types, pore classes, lithofacies, cyclostratigraphy, Q-units of Perkins (1977), formations, and hydrogeologic units...... 30 9. Conceptual facies model showing relations between major lithofacies, depositional environments, and pore classes for the study area...... 31 10-12. Diagrams showing: 10. Idealized fifth-order cycles for the Fort Thompson Formation and Miami Limestone showing relations between lithofacies, depositional environments, porosity (pore classes), and ground-water flow types...... 34 11. Relation between pore classes I and III and touching-vug and conduit pore types, respectively, for the Fort Thompson Formation and Miami Limestone of the Biscayne aquifer in the study area...... 37 12. Relation between pore class II and matrix porosity...... 38 13. Hydrostratigraphic correlation section A-A’ between the S-3163 and S-3164 production wells, including six digital image logs from observation and injection wells at the Northwest Well Field...... 39 14. Digital image of a borehole wall that spans a highly porous and permeable stratiform ground-water flow zone at the base of high-frequency cycle HFC2e2 in well G-3816..... 40
15. Three-dimensional conceptual hydrogeologic model of the Biscayne aquifer for the study area in north-central Miami-Dade County...... 41 16. Exploded view showing much of the geometry of the upper surfaces of the three- dimensional conceptual hydrogeologic model of the Biscayne aquifer for the study area in north-central Miami-Dade County...... 42 17-31. Maps showing: 17. Altitude of the top of the upper zone of pore class I of the Biscayne aquifer...... 44 18. Thickness of the upper zone of pore class I of the Biscayne aquifer...... 45 19. Altitude of the top of the upper zone of pore class III of the Biscayne aquifer...... 46 20. Thickness of the upper zone of pore class III of the Biscayne aquifer...... 47 21. Altitude of the top of the upper zone of pore class II of the Biscayne aquifer...... 48 22. Thickness of the upper zone of pore class II of the Biscayne aquifer...... 49 23. Altitude of the top of the middle zone of pore class I of the Biscayne aquifer...... 50 24. Thickness of the middle zone of pore class I of the Biscayne aquifer...... 51 25. Altitude of the top of the lower zone of pore class III of the Biscayne aquifer...... 52 26. Thickness of the lower zone of pore class III of the Biscayne aquifer...... 53 27. Altitude of the top of the lower zone of pore class II of the Biscayne aquifer...... 54 28. Thickness of the lower zone of pore class II of the Biscayne aquifer...... 55 29. Altitude of the top of the lower zone of pore class I of the Biscayne aquifer...... 56 30. Thickness of the lower zone of pore class I of the Biscayne aquifer...... 57 31. Altitude of the base of the lower zone of pore class I of the Biscayne aquifer...... 58 32. Graph showing number of occurrences of various preferential flow zones in 16 test coreholes fully penetrating the Biscayne aquifer in the study area, verified with heat-pulse or spinner flowmeter measurements, or both...... 62 33-35. Comparison of borehole image, computed vuggy porosity, geophysical, and flowmeter logs showing evidence for inflow of ground water from: 33. A preferential flow zone into the borehole of the G-3782 test corehole...... 63 34. Two preferential flow zones into the borehole of the G-3788 test corehole...... 64 35. A preferential flow zone into the borehole of the G-3793 test corehole...... 65
Tables
1. List of all test coreholes drilled during this study...... 9-11 2. Occurrence of stratigraphically important benthic foraminiferal taxa and other allochems in selected test coreholes...... 18-24 3. Foraminiferal biofacies and associated interpretive paleoenvironments...... 24 4. Summary of lithofacies of the Miami Limestone, Fort Thompson Formation, and selected lithofacies of the Tamiami Formation in north-central Miami-Dade County...... 26-29 5. Ideal cycles of the Fort Thompson Formation and Miami Limestone...... 34 6. Terminology of stratigraphic cycle hierarchies and orders of cyclicity...... 35 7. Pore classes (I, II, III) related to aquifer attributes of the Miami Limestone and Fort Thompson Formation in the study area...... 38 8. Borehole-flowmeter, fluid-conductivity, and fluid-temperature data for wells that fully penetrate the Biscayne aquifer in the study area and collected over uncased, open-hole intervals...... 60-61 vi
Conversion Factors and Datums
Multiply By To obtain
inch (in.) 25.4 millimeter foot (ft) 0.3048 meter mile (mi) 1.609 kilometer square mile (mi2) 2.590 square kilometer gallon per minute (gal/min) 0.06309 liter per second
Temperature in degrees Fahrenheit (˚F) is converted to degrees Celsius (˚C) as follows: ˚C = (˚F–32)/1.8
Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 (NGVD 1929). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Altitude, as used in this report, refers to distance above the vertical datum.
Acronyms
BIPS Borehole Image Processing System ENP Everglades National Park FWWB Fair weather wave base FISC-WRS Florida Integrated Science Center for Water and Restoration Studies HFC High-frequency cycle NWWF Northwest Well Field PVC polyvinyl chloride SFWMD South Florida Water Management District SPT Standard penetration test SWB Storm wave base USGS U.S. Geological Survey WCA Water Conservation Area Other Abbreviated Units
ka kilo-annum ky kilo-year mD millidarcy mg/L milligram per liter ppt part per thousand µS/cm microsiemens per centimeter A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Three-Dimensional Conceptual Hydrogeologic Model of the Karstic Biscayne Aquifer, Southeastern Florida
By Kevin J. Cunningham1, Michael A. Wacker1, Edward Robinson2, Joann F. Dixon1, and G. Lynn Wingard3
Abstract measurements from 25 wells that fully penetrate the Biscayne aquifer. Six depositional environments for major lithologic A fundamental problem in the simulation of karst components of the Biscayne aquifer—the Tamiami Formation, ground-water flow and solute transport is how best to repre- Fort Thompson Formation, and Miami Limestone—include: sent aquifer heterogeneity as defined by the spatial distribution (1) middle ramp, (2) platform margin-to-outer platform, of porosity, permeability, and storage. Combined analyses of (3) open-marine platform interior, (4) restricted platform cyclostratigraphy, including lithofacies and depositional envi- interior, (5) brackish platform interior, and (6) freshwater ronments, and borehole-geophysical logs, has improved the terrestrial environments. High-frequency cycles form the conceptualization of porosity, permeability, and storage within the triple-porosity karstic Biscayne aquifer in an approxi- fundamental building blocks of the rocks composing the mately 95-square-mile study area of Miami-Dade County Biscayne aquifer. Vertical lithofacies successions, which have in southeastern Florida. The triple porosity of the Biscayne stacking patterns that reoccur, fit within the high-frequency aquifer is principally: (1) matrix of interparticle and sepa- cycles. Upward-shallowing subtidal cycles, upward-shal- rate-vug porosity, providing much of the storage, and under lowing paralic cycles, and aggradational subtidal cycles define dynamic conditions, diffuse-carbonate flow; (2) touching‑vug three types of ideal high-frequency cycles that occur within the porosity creating stratiform ground-water flow passageways; Fort Thompson Formation and Miami Limestone. Based on and (3) less common conduit porosity composed mainly of vertical cycle patterns, high-frequency cycles group into two bedding‑plane vugs, thin solution pipes, and cavernous vugs. cycle sets: an older progradational cycle set and an overlying These three conduit porosity types are all pathways for conduit younger aggradational cycle. ground-water flow. A primary observation is that a predictable vertical To develop an accurate three-dimensional conceptual pattern of porosity and permeability commonly exists within hydrogeologic model of the Biscayne aquifer in the study area, the three ideal cycles because the porosity and permeability a detailed analysis of data was conducted that include continu- relate directly to lithofacies. Sixteen major lithofacies of ously drilled cores, digital borehole images, borehole-fluid the Fort Thompson Formation and Miami Limestone have conductivity and temperature logs, and borehole-flowmeter been assigned to one of three pore classes (I, II, and III).
______1U.S. Geological Survey, Florida Integrated Science Center—Water and Restoration Studies, Miami, Florida. 2University of West Indies, Kingston, Jamaica. 3U.S. Geological Survey, Reston, Virginia. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Touching‑vug porosity and conduit porosity characterize pore 2000; Langevin, 2001; Sonenshein, 2001); however, the class I, which commonly comprises the lower part of upward- Biscayne aquifer is a triple-porosity (matrix, touching‑vug, shallowing cycles within the Fort Thompson Formation and and conduit porosity) karst aquifer (Vacher and Mylroie, 2002; an upper aggradational cycle of the Miami Limestone. Matrix Cunningham and others, 2004b; 2004c). As a consequence, porosity distinguishes pore class II, which commonly occurs rates of flow within the conduit pore system can be more in the upper part of the upward-shallowing subtidal cycles rapid than within the matrix, as demonstrated by a tracer and middle part of the upward-shallowing paralic cycles. test conducted by the U.S. Geological Survey (USGS) at Micrite-dominated, leaky, low-permeability lithologies are the Northwest Well Field (NWWF) in Miami-Dade County characteristic of pore class III, which commonly caps upward- (Renken and others, 2005). Results of this test indicated that shallowing paralic cycles and occurs throughout much of a the apparent mean advective flow velocity of the tracer was lower aggradational cycle of the Miami Limestone. These one order of magnitude or greater than predictions by model relations among lithofacies, cyclicity, and aquifer attributes simulations assuming only porous media. A realistic concep- (porosity, permeability, and storage) are crucial features of the tual hydrogeologic model of the Biscayne aquifer, especially architecture of a three-dimensional conceptual hydrogeologic its karst limestone, is needed for development of numerical model of the karstic Biscayne aquifer. This study shows that simulations that can reliably predict ground-water flow and development of these relations is critical to producing a real- solute transport through the aquifer’s triple-porosity hydrogeo- istic cycle-based karstic aquifer framework for the Biscayne logic framework. aquifer and for karst aquifers within other platform carbonates. A fundamental problem in the simulation of karst ground- water flow and solute transport is how best to represent aquifer heterogeneity as defined by the spatial distribution of porosity, permeability, and storage. By definition, karst carbonate aqui- Introduction fers contain dissolution-generated conduits that allow rapid movement of ground water, often as turbulent flow (White, During the past century, the Everglades and its watershed 2002). Carbonate conduit flow systems pose a unique problem have been altered substantially by human activities, including because of the complex variations in lithofacies and diagenetic the development of a highly managed hydrologic system in history that contribute to their heterogeneity. Existing karst southern Florida. This hydrologic system of canals, levees, and flow models can be improved if conceptual hydrogeologic pumping stations was developed to meet an increasing demand models accurately delineate the distribution of conduits for water supply as a result of a rapidly growing urban popula- and aquifer matrix (White, 1999). This is especially true of tion and intensive agricultural activities. As a consequence, Paleozoic karst aquifers that can include pipe-like conduits; much of the Everglades, the unconfined karstic Biscayne these may be single caves or have a complex “branchwork aquifer, and major estuarine systems in southern Florida pattern” (White and White, 2001). In younger Cretaceous and presently do not receive sufficient quantity or distribution of Cenozoic karst aquifers, zones of high porosity have been water during times when it is needed most. An adequate water shown to occur within, or as equivalent to, small-scale depo- supply is essential to restoring the Everglades and its water- sitional cycles (Edwards aquifer—Hovorka and others, 1996, shed and maintaining sustainable population growth. 1998; Floridan aquifer—Budd, 2001; Ward and others, 2003; In southeastern Florida, ground-water supply is Budd and Vacher, 2004; Biscayne aquifer—Cunningham and augmented by surface-water storage in large-scale water- others, 2004b; 2004c; 2006, in press), indicating a well- conservation areas (fig. 1) and Everglades National Park defined cyclostratigraphic framework that can be used to map (ENP). Surface water seeps into the Biscayne aquifer from the the three-dimensional aspects of karst ground-water flow. wetlands and then moves as ground water beneath a system In 1998, the USGS, in cooperation with the South Florida of levees and canals on the eastern perimeter of the wetlands, Water Management District (SFWMD), initiated a study that flowing toward agricultural, urban, and coastal areas to the identified and characterized candidate preferential ground- east. Sustainable ground-water levels east of the wetlands water flow zones in the upper part of the shallow karst lime- are critical to maintaining water levels at water-supply wells, stone of the Biscayne aquifer in north-central Miami-Dade preventing saltwater intrusion along the coast, and restoring County using cyclostratigraphy, ground-penetrating radar, the quantity, quality, timing, and distribution of freshwater to borehole-geophysical logs, continuously drilled cores, and Biscayne Bay. paleontology (Cunningham and others, 2004b). This applica- To develop a water budget that meets natural, agricul- tion of cyclostratigraphy has proven critical to development of tural, and urban needs, it is necessary to accurately model a new conceptual hydrogeologic framework within the upper the movement of ground water and associated loads from part of the Biscayne aquifer (Cunningham and others, 2004b; the surface-water storage areas to the coast―an approach that 2004c). In 2002, the USGS, in cooperation with the SFWMD, involves numerical simulation of ground-water flow and initiated the current study, which extends the shallow high- solute transport in the Biscayne aquifer. Recent ground-water resolution hydrostratigraphic framework to the base of the flow models for the Biscayne aquifer assume flow through Biscayne aquifer. The purpose of the current study is to define porous media (Nemeth and others, 2000; Wilsnak and others, and map the spatial variations in the hydrogeology of the karstic Introduction
Lake Okeechobee
1
GULF OF MEXICO 2A 2B
OCEAN
3A
TLANTIC
A
3B
EXPLANATION STUDY AREA
EVERGLADES AGRICULTURAL AREA EVERGLADES NATIONAL PARK
WATER-CONSERVATION AREA 3A AND NUMBER BIG CYPRESS NATIONAL PRESERVE NATIVE AMERICAN LAND
0 25 MILES
0 25 KILOMETERS Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 1. Location of study area, Federal and State lands, and agricultural areas in southern Florida.
Biscayne aquifer in the context of a cyclostratigraphic frame- work in an approximate 95-mi2 area of north-central Miami- Dade County (fig. 1). The resulting conceptual hydrogeologic framework is critical in the development of procedures for reliable simulation of ground-water flow and solute transport 2005) done in cooperation with the USGS, Miami-Dade in the triple-porosity Biscayne aquifer. This study shows County Water and Sewer Department, and American Water that development of the methods used herein is critical to Works Research Foundation at the municipal NWWF (fig. 2). producing a realistic cycle-based karstic aquifer framework That study assessed the transport of pathogenic protozoa for the Biscayne aquifer and for karst aquifers within other within the Biscayne aquifer and examined the importance platform carbonates. The current effort also incorporates bore- of straining or filtration mechanisms that could impede their hole data from a recently completed study (Renken and others, advective movement. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°40´ 80°25´ 80°10´
26°00´ S-3170 S-3169 S-3168 BROWARD COUNTY G-3675 C-9 MIAMI-DADE COUNTY G-3732 G-3733 G-3793 G-3720 WATER G-3721 G-3674 G-3734 G-3794 CONSERVATION G-3772 G-3731 AREA 3A G-3773 G-3719 G-3723 G-3816 G-3722 L-67A G-3817 * n G-3718 G-3771 G-3728 d C-6
L-67C Northwest
L-30 owar Well Field Extensio G-3792 G-3717 Canal WATER G-3795 eek G-3727 CONSERVATION G-3724 G-3770 ennsuco G-3730
AREA 3B G-3673 P G-3726 Miami-Dade/Br G-3672 G-3729 Cr Snapper G-3688 G-3725 G-3686 G-3690 G-3689 G-3685 L-29 G-3691 G-3791 C-4 Miami G-3778 G-3671 G-3692 25°45´ G-3687 G-3697 G-3779 G-3782 G-3696 G-3780 G-3694 G-3681 Bird Road Canal G-3781 * G-3783 G-3695 G-3680 G-3710 G-3784 G-3693 G-3788 G-3711 G-3785 G-3679 G-3712 G-3713 G-3786 G-3678 G-3716 G-3787 * C-1W G-3684 G-3682 West Well Field EVERGLADES G-3714 G-3683 G-3790 NATIONAL G-3715 Bay
PARK G-3789
venue A
L-31N Biscayne EXPLANATION STUDY AREA Krome G-3696 TEST COREHOLE LOCATION AND NUMBER--Coreholes partly penetrate the Biscayne aquifer G-3789 TEST COREHOLE LOCATION AND NUMBER--Coreholes fully penetrate the Biscayne aquifer 0 5 MILES LEVEE OR CANAL 25°30´ Old South Dade Landfill L-31W 0 5 KILOMETERS
Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 2. Study area in Miami-Dade County showing location of major canals and levees, Northwest Well Field, Old South Dade Landfill, and test coreholes used in this study. Asterisk indicates that some test coreholes are grouped together at the same location, and partly or fully penetrate the Biscayne aquifer. Introduction
Purpose and Scope infiltration of surface water in WCA 3A and WCA 3B (fig. 2), causing a high head differential across Levee 30 (L‑30) at The purpose of this report is to document the second the edge of WCA 3B (fig. 2). Several studies that evaluated phase of the study, which applies cyclostratigraphic concepts permeability from the top of the Fort Thompson Formation to a database that includes borehole-geophysical logs, core- to the base of the Miami Limestone presented evidence for sample analyses, molluscan and foraminiferal paleontology, a dense low-permeability unit that spans this zone; some and borehole-flowmeter measurements. Specifically, this reports also identified other low-permeability units limiting report demonstrates how carbonate cyclostratigraphy was ground-water flow within the Biscayne aquifer (Shinn and crucial for defining the spatial distribution of porosity, Corcoran, 1988; Guardiario, 1996; Brown and Caldwell permeability, and storage within a triple-porosity (matrix, Environmental Engineers and Consultants, 1998; Cunningham touching‑vug, and conduit porosity) karst aquifer. and Wright, 1998; Genereux and Gaurdiario, 1998; Kaufman Integrated analysis of the database resulted in delineation and Switanek, 1998; Nemeth and others, 2000; Sonenshein, of vertical lithofacies successions, depositional environments, 2001; Cunningham and others, 2004b, 2004c; Cunningham porosity, and permeability of the Pleistocene karst limestone and others, 2006, in press; Krupa and Mullen, 2005). of the Biscayne aquifer in the context of a cyclostratigraphic Along the Levee 31W Canal at the eastern boundary of framework in north-central Miami-Dade County, Florida ENP, borehole-flowmeter measurements by Guardiario (1996) (figs. 1 and 2). A high-resolution cyclostratigraphic model is showed that the low-permeability unit spanning the upper Fort used throughout the entire thickness of the Biscayne aquifer Thompson Formation and lower Miami Limestone (figs. 3 over a wide area to select consistent correlable ground-water and 4) acts as a semiconfining unit, supporting vertical head flow zones, diffuse flow zones, and zones of leaky, low perme- differences and restricting the vertical movement of water. ability in the study area. That part of the Biscayne aquifer At a nearby site, canal drawdown experiments were used with included in the upper part of the Pliocene Tamiami Formation borehole-flowmeter measurements to establish a high-resolu- by Fish and Stewart (1991) is not a major focus of this study. tion hydraulic conductivity profile of the Biscayne aquifer (Genereux and Guardiario, 1998). Results indicated the pres- ence of a low hydraulic conductivity zone at the top of the Fort Description of Study Area Thompson Formation (Genereux and Guardiario, 1998), which presumably is equivalent to the low hydraulic conductivity The study area of Cunningham and others (2004b) was zone that spans the upper Fort Thompson Formation and lower the approximate extent of the 89-mi2 Lake Belt area (fig. 2), part of the Miami Limestone in north-central Miami-Dade an up to 6-mi-wide region that separates urban Miami-Dade County. The zone also has been identified as a semiconfining County from natural wetlands of ENP and Water Conservation unit at the Old South Dade Landfill (fig. 2) in Miami-Dade Area (WCA) 3B. The Lake Belt area primarily is used for rock County (Shinn and Corcoran, 1988; Brown and Caldwell mining and public-water supply and as an environmentally Environmental Engineers and Consultants, 1998; Cunningham protective freshwater wetland (Miami-Dade County Lake Belt and Wright, 1998). Vertical head differences measured by Plan Implementation Committee, 1998). The current effort Sonenshein (2001) indicated that this zone can restrict vertical expands the study locale of Cunningham and others (2004b) flow between surface water and ground water in the wetlands southward by about 1.5 mi or 6 mi2. (Compare fig. 2 in west of L‑30 in Miami-Dade County (fig. 2). Recent ground- Cunningham and others (2004b) with fig. 2 in this report.) water simulations by Nemeth and others (2000) along Levee 31N (L‑31N) and Sonenshein (2001) near L‑30 have modeled Previous Studies this zone as a low-permeability unit. This low-permeability unit and a deeper unit are shown in cross sections and a three- The goals of this study have been addressed by a wide dimensional conceptual hydrogeologic model of the upper range of studies that encompass different geologic disciplines. part of the Biscayne aquifer (Cunningham and others, 2004b, The disciplines include those that characterize: (1) ground- plates 1-5 and fig. 39, respectively) throughout most of the water flow in the Biscayne aquifer; (2) variability in porosity, Lake Belt area. permeability, and storage within the Biscayne aquifer; and Cunningham and others, (2004c; 2006, in press) mapped (3) the hydrogeology of the Biscayne aquifer or the physical several low-permeability units throughout the Biscayne aquifer properties of carbonate strata using geophysical methods and along L‑31N and in a small area of the NWWF. Cunningham other techniques. and others (2004c) also presented evidence for vertical head Numerous studies that have investigated the presence of differences between three zones of high permeability within low-permeability zones in the Biscayne aquifer indicate the the lower, middle, and uppermost part of the Biscayne aquifer, existence of one or more semiconfining units. The presence of providing evidence for the retardation of vertical leakance of low-permeability zones near the top of the Biscayne aquifer ground water in the aquifer at two or more levels. Cunningham was first suggested by Klein and Sherwood (1961), who pro- and others (2006, in press) and Renken and others (2005) posed that two thin layers of dense limestone retard downward conducted a forced-gradient convergent tracer test using A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Thin intercalations WEST of Holocene Lake Flirt Marl EAST Miami Limestone and peat or peat only partly cover Miami Limestone Pamlico Sand
Water-table aquifer NGVD 1929 Miami Limestone NGVD 1929 Ana- Biscayne stasia aquifer Fort Thompson Fm Pinecrest Sand Formation Biscayne CSU aquifer 50 50
Key Largo Limestone
1929 Anastasia 1929
FEET FEET
Ochopee Fm
IN IN
GVD Limestone gray limestone GVD
N 100 100 N aquifer Tamiami Ochopee Limestone
TITUDE, Formation TITUDE,
AL AL
BELOW BELOW SA Semiconfining 150 150 Unnamed unit formation
ICU Peace River Formation
200 200 0 5 MILES
0 5 KILOMETERS VERTICAL SCALE GREATLY EXAGGERATED
EXPLANATION
OOLITIC LIMESTONE HYDROSTRATIGRAPHIC BOUNDARY PELECYPOD RUDSTONE AND FLOATSTONE; LITHOSTRATIGRAPHIC BOUNDARY MINOR CALCRETE BEDS AND LAMINATIONS; LOCALLY PLANORBELLA FLOATSTONE CSU CONFINING TO SEMICONFINING UNIT PELECYPOD RUDSTONE AND FLOATSTONE; ICU INTERMEDIATE CONFINING UNIT MINOR PELECYPOD-RICH QUARTZ SAND AND SA SAND AQUIFER SANDSTONE REEF ROCK AND MARINE CARBONATE Fm FORMATION QUARTZ SAND OR SANDSTONE SILT TERRIGENOUS MUDSTONE
Figure 3. Relation of geologic and hydrogeologic units of the surficial aquifer system across central Miami-Dade County (modified from Reese and Cunningham, 2000).
Rhodamine WT and deuterated water and made borehole-fluid Many recent studies have verified that digital electronic temperature and flowmeter measurements at an observation images of borehole walls can be useful for quantifying vuggy well. Results strongly suggested that ground water in the porosity (Hickey, 1993; Newberry and others, 1996; Hurley Biscayne aquifer in the area of the well field preferentially and others, 1998; 1999) in petroleum reservoirs and fractures moves along stratiform zones of touching‑vug porosity; in aquifers (Williams and Johnson, 2000). By quantifying typically, these zones are located at the base of high-frequency vuggy porosity in borehole images, these researchers were cycles, which can be mapped in three dimensions. Krupa and able to identify fluid-flow zones. Cunningham and others Mullen (2005) presented a detailed hydrogeologic study of (2004a) reported in detail the development of a method for the low-permeability unit that spans the upper Fort Thompson quantifying vuggy porosity seen in digital borehole images Formation and lower Miami Limestone. of limestone in the Biscayne aquifer. Cunningham and others Methods of Investigation
South Florida Florida Keys Miami-Dade Florida Keys Northwest Everglades National Park Levee 31N (modified from (Perkins, (Harrison and County (Multer and Well Field (modified from Hickey, 2004) Cunningham and others, 2004c)
unit
unit 1977) others, 1984) (Galli, 1991) others, 2002) (this study)
Epoch
Geologic
Q unit Q unit Parasequence Q unit Q unit Q subunit Q unit HFC VLS Q unit HFC Hydrogeologic -- - Post------Q5e Q5 Q5 - Q5e Q5e - Q5 HFC5 - Q5 HFC5e
Q4b Q4b b Q4 PS “C” Q4 Q4 HFC4 - Q4 HFC4
Miami Limestone Q4a Q4a a
PS 1 b VLS3b HFC3b Q3 Q3 Q3 Q3 Q3 HFC3 Q3 PS 2 a VLS3a HFC3a
d VLS2g HFC2h c VLS2f HFC2g3 Pleistocene PS 3 b VLS2e HFC2g2 - HFC2g1 Q2 Q2 to Q2 Q2 - Q2 HFC2 Q2 a VLS2d -
Biscayne aquifer PS7 VLS2c HFC2e2 b VLS2b - Q1 a VLS2a HFC2d ? HFC2c
Fort Thompson Formation Q1 Q1 Q1 Q1? HFC2b
HFC2a Cunningham STUDY AREAS & SITES and others Perkins (1977) (2004c)
unit
amiami Harrison and others (1984) and
T
Pliocene Formation Multer and others (2002) This
Semiconfining Hickey study Galli (1991) (2004) EXPLANATION Local study sites Tamiami Formation HFC High-frequency cycle PS Paraseqeunce VLS Vertical lithofacies succession
Figure 4. Correlation of ages, formations, stratigraphy, and hydrogeologic units of the Tamiami Formation, Fort Thompson Formation, and Miami Limestone from this and other studies.
(2004b; 2004c) also presented numerous digital borehole Methods of Investigation images from the Biscayne aquifer, which were used to calcu- late the percentage of vuggy porosity. A multidisciplinary approach was used to characterize the pore system within a cyclic hydrogeologic framework of Acknowledgments the entire Biscayne aquifer. This approach involved integrating data from core analyses and borehole-geophysical logs and Cynthia Gefvert and Steven Krupa at the SFWMD gave from cyclostratigraphic and paleontologic analyses. useful advice and logistical support during the study. Gene Shinn and Barclay Shoemaker of the USGS and Pamela Hallock Muller of the University of South Florida provided Drilling, Well Completion, Core Analysis, and technical reviews, and Mike Deacon and Rhonda Howard Borehole-Geophysical Logging provided editorial reviews. Borehole data collected as part of a cooperative project funded by the USGS, Miami-Dade Twenty-five continuously cored wells that fully penetrate County Water and Sewer Department, and American Water the Biscayne aquifer form the foundation of this study (table 1 Works Research Foundation at the Northwest Well Field were and fig. 2). Other partially penetrating wells (fig. 2) from included in this study. studies by Cunningham and others (2004b; 2004c; 2006, A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla. in press) were used in support of interpretations. In 1998, the The injection (G‑3773) and monitoring (G‑3772) wells at the Miami-Dade County Water and Sewer Department directed NWWF (fig. 2 and table 1) were constructed with solid PVC the drilling of 3 of the 25 wells as test coreholes adjacent to casing from land surface to near their base and with an open- production wells S‑3168, S‑3169, and S‑3170 at the NWWF hole interval at their base. The three test coreholes (S‑3168, (fig. 2). The USGS supervised the drilling of the remaining S‑3169, and S‑3170) drilled next to production wells at the 22 wells. Four wells were drilled as test coreholes (G‑3671, NWWF (fig. 2 and table 1) were abandoned after cores were G‑3673, G‑3674, and G‑3675) in 1998 by Cunningham and acquired. others (2004b). Two test coreholes (G‑3770 and G‑3771) Geophysical logs were collected in all 22 wells (app. I) located about 1 mi east of the Miami-Dade-Broward/Pennsuco drilled under the supervision of the USGS, but no logs were Canal (fig. 2), were completed in 2002. Another two of the collected in the test coreholes adjacent to production wells 25 wells were completed in 2003, one as a monitoring well S‑3168, S‑3169, and S‑3170 (fig. 2). The types of logs col- (G‑3772) and the other as an injection well (G‑3773); both lected by the USGS include the following: electromagnetic wells were constructed for a tracer study (Cunningham and induction, three-arm caliper, borehole-fluid resistivity and others, 2006, in press; Renken and others, 2005). Seven temperature, full waveform sonic, heat pulse and spinner test coreholes (G‑3778, G‑3779, G‑3782, G‑3783, G‑3784, flowmeter, ALT OBI‑40 Mark IIITM digital optical televiewer G‑3788, and G‑3789) were drilled in 2003 on top of the L‑31N (RAAXTM Borehole Imaging Processing System [BIPS] berm or along its east side (Cunningham and others, 2004c). digital optical televiewer in the G‑3671, G‑3673, G‑3674, and An additional seven test coreholes (G‑3733 and G‑3790 to G‑3675 test coreholes only), and LavalTM video (except for the G‑3795) were completed between late 2003 and early 2004. G‑3671, G‑3673, G‑3674, and G‑3675 test coreholes). Vuggy Test corehole G‑3733 was originally completed in the middle porosity logs (Cunningham and others, 2004a) also were part of the Biscayne aquifer (Cunningham and others, 2004b), created for each of the wells logged by the USGS. but redrilled as fully penetrating the Biscayne aquifer for this To construct hydrogeologic cross sections, data from nine study. test coreholes that only partly penetrate the Biscayne aquifer Continuously drilled 3.4-in.‑diameter cores from the also are included in this study (G‑3696, G‑3720, G‑3723, four test coreholes (G‑3671, G‑3673, G‑3674, and G‑3675) G‑3725, G‑3728, G‑3730, G‑3731, G‑3732, and G‑3734). that fully penetrate the Biscayne aquifer and completed in Cunningham and others (2004b) describe the details of the 1998 were collected using a wireline coring method to the drilling, completion, and geophysical logging for these test total depth of each test corehole. Continuously drilled 4- coreholes. in.‑diameter cores were collected from the injection (G‑3773) For this study, an analysis was conducted of core samples and monitoring (G‑3772) wells at the NWWF using the same (either 3.4-. or 4.0-in.‑diameter) obtained from the 25 wells wireline coring method down to the first depth that quartz that fully penetrate the Biscayne aquifer in the study area sands were penetrated; the remaining depths of both wells were then cored using a split-barrel sampler and standard (fig. 2). Most of the core samples were slabbed and visually penetration test (SPT) methodology (Shuter and Teasdale, analyzed using a 10X-magnification hand lens and binocular 1989). All other test coreholes drilled under the supervision microscope. Standard transmitted-light petrography was used of the USGS (G‑3733, G‑3770, G‑3771, G‑3778, G‑3782 to to examine 215 thin sections. Cores and thin sections were G‑3784, G‑3788 to G‑3795) were drilled using a conventional analyzed to help determine lithofacies, vertical trends in litho- hydraulic rotary coring method with freshwater as a drilling facies, sedimentary structures, cycle boundaries, and assess fluid (Shuter and Teasdale, 1989) to a depth where quartz how features laterally varied and correlated. Lithofacies were sands were first encountered; the remaining depths of each defined by allochem types, fabric, sedimentary structures, test corehole were then drilled using a split-barrel sampler bedding type, and diagenetic features using a combination of and SPT methodology (table 1). The exception was well classification schemes and terminology from Dunham (1962), G‑3779 (fig. 2), which was drilled only using the conventional Embry and Klovan (1971), and Lucia (1999). The rock color hydraulic rotary coring method to a short depth where the first of dry core samples was recorded by comparing them to a quartz sands were encountered. Munsell rock-color chart (Geological Society of America, Seventeen test coreholes that fully penetrate the Biscayne 1991). Core Laboratories, Inc., measured horizontal and aquifer and drilled under the supervision of the USGS were vertical permeability, porosity, and grain density of 267 whole- completed as open-hole stratigraphic tests with a short length core samples collected from 13 wells (app. II). All continuous of solid polyvinyl chloride (PVC) casing at the uppermost part cores collected for this study were archived at the USGS of the well (table 1). The monitoring wells (G‑3778, G‑3779, Florida Integrated Science Center for Water and Restoration and G‑3784) that fully penetrate the Biscayne aquifer on top Studies (FISC-WRS) in Fort Lauderdale, Fla. Relations of the L‑31N berm were completed with 2-in.‑diameter solid between lithofacies and petrophysical properties (porosity PVC with a 2-ft-long screened interval in limestone of the and permeability) were assessed using methods prescribed by Biscayne aquifer or underlying semiconfining unit (fig. 3). Lucia (1995; 1999). Methods of Investigation
Table 1. List of all test coreholes drilled during this study.
[Well locations are shown in figure 2. All wells are located in Miami-Dade County, Florida. Latitudes and longitudes referenced to North American Datum of 1983. Altitude of measuring point is land surface referenced to the National Geodetic Vertical Datum of 1929 (NGVD 1929). All wells are test coreholes unless otherwise noted. Drilling method: AR, air rotary; CC, conventional core; MR, mud rotary; SPT, split barrel sampler using standard penetration test methodology. Other acronyms: NA, not applicable; NWWF, Northwest Well Field; PVC, solid polyvinyl chloride; WLC, wireline core]
Well Altitude Local Total Depth of fully End USGS site of mea- Well well Drilling Drilling Longi- depth bottom pene- date of identification Latitude suring construction Comments identi- contractor method tude drilled of casing trates construc- number point material fier (feet) (feet) Biscayne tion (feet) aquifer
G-3671 254456080295301 Amdrill WLC 254456 802953 7.5 150 3.5-in. PVC 10 Yes 8-7-98 Open interval to 55.5 feet G-3672 254822080290201 Amdrill WLC 254822 802902 20 45 3.5-in. PVC 18 No 8-8-98 Abandoned-redrilled at G-3673 G-3673 254822080290202 Amdrill WLC 254822 802902 20 160 3.5-in. PVC 18 Yes 8-10-98 -- G-3674 255529080251101 Amdrill WLC 255529 802511 10 160 3.5-in. PVC 10 Yes 8-16-98 Destroyed G-3675 255723080261301 Amdrill WLC 255723 802613 8 90 No casing set NA Yes 8-21-98 -- G-3678 254050080295401 Amdrill WLC 254050 802954 9 35 3.5-in. PVC 10 No 5-22-99 -- G-3679 254129080294301 Amdrill WLC 254129 802943 9 40 3.5-in. PVC 10 No 5-23-99 -- G-3680 254252080294601 Amdrill WLC 254252 802946 9 40 3.5-in. PVC 11 No 5-23-99 -- G-3681 254349080294901 Amdrill WLC 254349 802949 9 45 3.5-in. PVC 11 No 5-23-99 -- G-3682 253937080295001 Amdrill WLC 253937 802950 10 30 3.5-in. PVC 11 No 5-24-99 -- G-3683 253940080282601 Amdrill WLC 253940 802826 8 35 3.5-in. PVC 11 No 5-24-99 Destroyed G-3684 253943080272201 Amdrill WLC 253943 802722 8 35 3.5-in. PVC 10 No 5-24-99 Destroyed G-3685 254543080305501 Amdrill WLC 254543 803055 8 30 3.5-in. PVC 11 No 5-25-99 Destroyed G-3686 254541080294301 Amdrill WLC 254541 802943 10 30 3.5-in. PVC 10 No 5-25-99 Destroyed G-3687 254542080284401 Amdrill WLC 254542 802844 10 30 3.5-in. PVC 11 No 5-25-99 -- G-3688 254542080270001 Amdrill WLC 254542 802700 9.5 30 3.5-in. PVC 10 No 5-26-99 Destroyed G-3689 254542080259001 Amdrill WLC 254542 802590 9 30 3.5-in. PVC 10 No 5-26-99 Destroyed G-3690 254635080285801 Amdrill WLC 254635 802858 9 30 3.5-in. PVC 11 No 5-26-99 -- G-3691 254542080315301 Amdrill WLC 254542 803153 8 35 3.5-in. PVC 10 No 5-27-99 Destroyed G-3692 254541080260001 Amdrill WLC 254541 802600 9 30 3.5-in. PVC NA No 5-27-99 Casing fell to borehole bottom G-3693 254224080284701 Amdrill WLC 254224 802847 10.5 35 3.5-in. PVC NA No 6-2-99 Casing fell to borehole bottom. Destroyed G-3694 254336080284401 Amdrill WLC 254336 802844 10 35 3.5-in. PVC 10 No 6-2-99 Destroyed G-3695 254339080272401 Amdrill WLC 254339 802724 9.5 35 3.5-in. PVC 11 No 6-3-99 -- G-3696 254341080261101 Amdrill WLC 254341 802611 10 35 3.5-in. PVC 10 No 6-3-99 Lower borehole collapsed G-3697 254429080265401 Amdrill WLC 254429 802654 9 30 No casing set NA No 6-3-99 Well abandoned G-3710 254310080284801 U.S. Drilling CC 254310 802848 10 33 5-in.PVC 8 No 4-20-00 -- G-3711 254300080284701 U.S. Drilling CC 254300 802847 10 37 5-in. PVC 7 No 4-20-00 -- G-3712 254250080284601 U.S. Drilling CC 254250 802846 10 28 5-in. PVC 7 No 5-1-00 -- G-3713 254245080284501 U.S. Drilling CC 254245 802845 10 32.5 5-in. PVC 7 No 5-2-00 -- G-3714 253937080292901 U.S. Drilling CC 253937 802929 9 23 5-in. PVC 7 No 5-3-00 -- G-3715 253938080292301 U.S. Drilling CC 253938 802923 9 23 5-in. PVC 5 No 5-3-00 -- G-3716 253943080272301 U.S. Drilling CC 253943 802723 8 28 5-in. PVC 9 No 5-4-00 Destroyed G-3717 255039080290101 U.S. Drilling CC 255039 802901 9 43 5-in. PVC 7 No 5-8-00 -- G-3718 255220080290301 U.S. Drilling CC 255220 802903 9 30 5-in. PVC 8 No 5-9-00 -- 10 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Table 1. List of all test coreholes drilled during this study. (Continued)
Well Altitude Local Total Depth of fully End USGS site of mea- Well well Drilling Drilling Longi- depth bottom pene- date of identification Latitude suring construction Comments identi- contractor method tude drilled of casing trates construc- number point material fier (feet) (feet) Biscayne tion (feet) aquifer
G-3719 255355080284301 U.S. Drilling CC 255355 802843 9 30 5-in. PVC 6.5 No 5-10-00 -- G-3720 255530080271301 U.S. Drilling CC 255530 802713 9 31 5-in. PVC 5 No 5-11-00 -- G-3721 255424080271201 U.S. Drilling CC 255424 802712 10 30 5-in. PVC 9 No 5-12-00 -- G-3722 255326080270901 U.S. Drilling CC 255326 802709 10 32 5-in. PVC 8 No 5-12-00 -- G-3723 255328080251201 U.S. Drilling CC 255328 802512 8 45 5-in. PVC - No 5-15-00 Casing fell to borehole bottom G-3724 254942080285801 U.S. Drilling CC 254942 802858 9 30 5-in. PVC 7 No 5-16-00 Destroyed G-3725 254655080231201 U.S. Drilling CC 254655 802312 6 31.5 5-in. PVC 6 No 5-17-00 Destroyed G-3726 254825080231201 U.S. Drilling CC 254825 802312 7 33 5-in. PVC 10 No 5-18-00 Borehole collapsed to 16 feet below land surface G-3727 255033080231301 U.S. Drilling CC 255033 802313 8 43 5-in. PVC 8.7 No 5-30-00 Destroyed G-3728 255154080231301 U.S. Drilling CC 255154 802313 7 38 5-in. PVC 6 No 5-31-00 Destroyed G-3729 254843080261101 U.S. Drilling CC 254843 802611 6 36 5-in. PVC 6 No 6-1-00 -- G-3730 254842080250801 U.S. Drilling CC 254842 802508 6 40 5-in. PVC 7 No 6-2-00 Casing fell to borehole bottom G-3731 255408080231801 U.S. Drilling CC 255408 802318 10 43 5-in. PVC 7.5 No 6-5-00 -- G-3732 255724080235401 U.S. Drilling CC 255724 802354 6 48 5-in. PVC 5 No 8-21-00 -- G-3733 255724080213401 U.S. Drilling CC 255724 802135 6 43 5-in. PVC 9.8 No 9-8-00 -- G-3733 255724080213401 MACTEC CC/SPT 255724 802135 6 63 10-in. PVC 3 Yes 12-19-03 Original well deep-ened; 6.5-in. diameter hole below 10-in. casing. Open interval to 57 feet below land surface G-3734 255540080222501 U.S. Drilling CC 255540 802225 8 33 5-in. PVC 6 No 9-8-00 -- G-3770 254957080260101 U.S. Drilling CC/SPT 254957 802601 6.7 80 6-in. PVC 8.6 Yes 11-06-02 Open interval to 58 feet below land surface G-3771 255159080260501 U.S. Drilling CC/SPT 255159 802605 6.0 80 6-in. PVC 8.2 Yes 11-18-02 Open interval to 58 feet below land surface G-3772 255029080245001 Intercounty WLC/ 255029 802450 8.0 100 2-in. PVC 33.5 Yes 01-14-03 Monitoring well, open SPT interval to 64 feet below land surface G-3773 255029080245304 Intercounty WLC/ 255029 802453 8.1 100 6-in. PVC 33.5 Yes 01-29-03 Injection well, open SPT interval to 66 feet below land surface G-3778 254447080295201 MACTEC CC/ 254447 802952 16.4 111.4 2-in. PVC 103.3 Yes 09-24-03 Monitoring well, screened SPT/ interval 101.3 to 103.3 feet below land surface MR G-3779 254447080295202 MACTEC CC 254447 802952 16.2 65 2-in. PVC 54.2 Yes 09-18-03 Monitoring well, screened interval 52.2 to 54.2 feet below land surface G-3780 254447080295203 MACTEC MR 254446 802952 16.4 34 2-in. PVC 33.4 No 09-22-03 Monitoring well, screened interval 31.4 to 33.4 feet below land surface G-3781 254447080295204 MACTEC MR 254446 802952 16.5 19 2-in. PVC 18.6 No 10-01-03 Monitoring well, screened interval 16.6 to 18.6 feet below land surface G-3782 254351080295001 MACTEC CC/SPT 254351 802950 8.9 70 6-in. PVC 9.2 Yes 07-27-03 Open interval to 57 feet below land surface G-3783 254257080294801 MACTEC CC/SPT 254257 802948 9.1 71 6-in. PVC 10 Yes 08-05-03 Open interval to 47 feet below land surface Methods of Investigation 11
Table 1. List of all test coreholes drilled during this study. (Continued)
Well Altitude Local Total Depth of fully End USGS site of mea- Well well Drilling Drilling Longi- depth bottom pene- date of identification Latitude suring construction Comments identi- contractor method tude drilled of casing trates construc- number point material fier (feet) (feet) Biscayne tion (feet) aquifer
G-3784 254207080294601 MACTEC CC/ 254207 802946 15.7 113.7 2-in. PVC 100.5 Yes 10-07-03 Monitoring well, screened SPT/ interval 98.5 to 100.5 feet below land surface MR G-3785 254207080294602 MACTEC MR 254207 802946 15.8 45 2-in. PVC 44.4 No 10-15-03 Monitoring well, screened interval 42.4 to 44.4 feet below land surface G-3786 254207080294603 MACTEC MR 254207 802946 15.6 29 2-in. PVC 28.4 No 10-03-03 Monitoring well, screened interval 26.4 to 28.4 feet below land surface G-3787 254207080294604 MACTEC MR 254207 802946 15.9 19 2-in. PVC 19 No 10-02-03 Monitoring well, screened interval 16.9 to 18.9 feet below land surface G-3788 254128080294401 MACTEC CC/SPT 254128 802944 8.6 70 6-in. PVC 9.4 Yes 08-22-03 Open interval to 48 feet below land surface G-3789 253813080295001 MACTEC CC/SPT 253813 802950 8.0 70 6-in. PVC 9.6 Yes 08-25-03 Open interval to 58 feet below land surface G-3790 253944080265801 MACTEC CC/SPT 253944 802658 8.0 76 10-in. PVC 3 Yes 11-21-03 6.5-in. diameter hole below 10-in. casing. Open interval to 68 feet below land surface G-3791 254541080250301 MACTEC CC/SPT 254541 802503 8 79 10-in. PVC 5.8 Yes 12-03-03 6.5-in. diameter hole below 10-in. casing. Borehole bridged at 47 feet below land surface G-3792 255036080231301 MACTEC CC/SPT 255036 802313 8 90 10-in. PVC 9.3 Yes 01-07-04 6.5-in. diameter hole below 10-in. casing. Open interval to 84 feet below land surface G-3793 255552080253901 MACTEC CC/SPT 255552 802539 10 76 10-in. PVC 5.3 Yes 12-17-03 6.5-in. diameter hole below 10-in. casing. Open interval to 74 feet below land surface G-3794 255420080282201 MACTEC CC/SPT 255420 802822 9 70 10-in. PVC 4.8 Yes 01-13-04 6.5-in. diameter hole below 10-in. casing. Borehole bridged at 48 feet below land surface G-3795 255015080290001 MACTEC CC/SPT 255015 802900 9 90.5 10-in. PVC 3.5 Yes 01-17-04 6.5-in. diameter hole below 10-in. casing. Open interval to 88 feet below land surface G-3816 255029080245302 Hydrologic AR 255029 802453 8.1 75 6-in. PVC 59.1 No 10-10-03 Injection well, open 59 to Associates 74 feet below land surface
G-3817 255029080245303 Hydrologic AR 255029 802453 8.1 45 6-in. PVC 32.9 No 10-11-03 Injection well, open 33 to Associates 43 feet below land surface
NWWF -- Professional CC -- -- 8 85 No casing set N/A Yes 8-13-98 Core was taken adjacent Core- Services to municipal water-supply hole Industries well. S-3168. Abandoned No. 13 NWWF -- Professional CC -- - 8 76 No casing set N/A Yes 8-12-98 Core was taken adjacent Core- Services to municipal water-supply hole Industries well. S-3169. Abandoned No. 14 NWWF -- Professional CC -- -- 8 95 No casing set N/A Yes 8-11-98 Core was taken adjacent Core- Services to municipal water-supply hole Industries well. S-3170. Abandoned No. 15 1 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Collection of Borehole-Fluid Flow Data G‑3773; however, both wells are within the West Well Field and flow velocities were higher than the resolution limits of To delineate borehole-fluid flow in the study area, digital the flowmeter (0.03 to 1.0 gal/min). optical borehole images, computed vuggy porosity data, Fluid-temperature, fluid-conductivity, and flowmeter caliper data, borehole-flowmeter data, fluid-conductivity measurements were conducted in 13 wells for which the data, and fluid-temperature data were collected for this synoptic or quasi-synoptic measurements were collected for study. These data were measured within uncased open-hole flowmeter data, conductivity, and temperature. Synoptic data intervals in test coreholes that fully penetrate the Biscayne were measured on the same day, and quasi-synoptic data were aquifer. Digital optical borehole images, computed vuggy collected within a period ranging from 2 to 8 days. Borehole- porosity, and caliper logs were useful for selecting candidate fluid and fluid-temperature logs are reported for a period high-permeability zones where fluid is flowing into or out of a from March 28, 2003, to April 6, 2004. Fluid-conductivity borehole. Borehole flowmeters were used to measure vertical and fluid-temperature logs were collected from wells G‑3671, flow within a single well, and the data were used to identify G‑3733, G‑3770, G‑3771, G‑3778, G‑3782,G‑3783, G‑3784, areas of inflow or outflow to or from the borehole, respec- and G‑3788 to G‑3795. tively. Differences in hydraulic head between two transmissive hydrogeologic units produce vertical flow within a borehole, which was measured using vertical flowmeter logs. Ground Molluscan and Benthic Foraminiferal water enters the borehole at the unit with the higher head and Paleontology flows toward and out of the borehole at the unit with the lower head. If the heads of different transmissive zones are the same, Taxonomy of mollusks and foraminifera from selected no vertical flow will occur in the borehole. lithofacies was determined to assist in interpretation of Either a heat-pulse flowmeter, spinner flowmeter, or both paleoenvironments. Mollusks from 13 core samples obtained were used to measure vertical borehole ground-water flow from the test coreholes adjacent to the S‑3168 and S‑3170 under ambient borehole conditions in the wells drilled under production wells (fig. 2) were prepared and identified at the supervision by the USGS. The accuracy of the heat-pulse USGS Paleontology Laboratory in Reston, Va. Core samples flowmeter measurements is limited because of the uncertainty were initially examined under a binocular microscope to concerning the amount of fluid flow bypassing the flexible- observe diagnostic characteristics of the molluscan taxonomy disk diverter on the flowmeter (Paillet, 2004). Cunningham and to compare the samples with those from previous studies and others (2006, in press) discussed measurements acquired (Mansfield, 1939; Olsson and Harbison, 1953; DuBar, 1958; with an electromagnetic flowmeter at wells G‑3772 and Olsson and Petit, 1964; Abbott, 1974; Portell and others, G‑3773 in the NWWF (fig. 2). 1992). Where appropriate, clay squeezes or latex casts were Logs of fluid conductivity, the reciprocal of fluid resis- made of the molluscan molds to aid in their identification. tivity, can be used to assess changes in concentration of dis- Many molluscan species present in the Pleistocene units of solved solids in the borehole fluid column (Keys, 1990). Fluid southern Florida are extant or represented by close relatives, conductivity logs were useful to identify areas of the borehole thus, living fauna are used to interpret paleoenvironmental set- that produce or receive water. Intervals of the borehole where tings. Publications by Perry and Schwengel (1955), Warmke there is inflow or outflow can be identified by sharp changes in and Abbott (1962), Abbott (1974), Andrews (1977), and borehole-fluid conductivity. Similarly, borehole-fluid tempera- Brewster-Wingard and others (2001) supported paleoenviron- ture logs can be useful for delineation of zones contributing water to (or losing water from) the borehole by linking sharp mental interpretations. changes in temperature to these intervals of inflow or outflow. Benthic foraminifera were identified to the genus level, Fluid-temperature logs, when used with flowmeter and fluid- where possible, for 215 thin sections. Seven biofacies were conductivity data to define the movement of water through the recognized; one was distinguished by its absence of benthic wells, best allowed for delineation of intervals with inflow or foraminifera, and six were classified based on data from Bock outflow from the borehole; thus, these logs provide informa- and others (1971) and on biofacies suggested by Poag (1981) tion on formation permeability. adapted to thin section analysis. The classification of biofacies Flowmeter data were used to observe vertical ground- by Poag (1981) is based on the predominant genera of benthic water flow under existing hydraulic conditions in 16 wells foraminifera present in a sample. Poag (1981) suggested during a period from December 20, 2002, to April 6, 2004. counting 200 to 300 free specimens to establish the presence Stationary heat-pulse flowmeter measurements within the of a particular biofacies; however, the number of recognizable limestone of the Biscayne aquifer were obtained from wells genera in samples used here is substantially less, thus, the G‑3671, G‑3733, G‑3770, G‑3771, G‑3778, G‑3782, G‑3783, interpreted assignments of biofacies are somewhat specula- G‑3784, and G‑3788 to G‑3795, and spinner flowmeter mea- tive. Data presented in Bock and others (1971), Rose and surements were collected from wells G‑3782, G‑3783,G‑3788, Lidz (1977), Poag (1981), and Lidz and Rose (1989) aided in G‑3789, G‑3790, and G‑3792 to G‑3795. Heat-pulse flow- the interpretation of paleoenvironmental conditions based on meter measurements were attempted at wells G‑3772 and foraminiferal taxonomy. Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer 13
Multidisciplinary Approach— and stratigraphic age of the Fort Thompson Formation were Characterizing the Geologic evaluated in the 13 samples collected for molluscan pale- ontology from two test coreholes adjacent to wells S‑3168 Framework of the Biscayne Aquifer and S‑3170 (fig. 2). The test coreholes near production wells Lithostratigraphy, molluscan and foraminiferal pale- S‑3168 and S‑3170 were drilled as part of a separate project ontology, lithofacies, depositional environments, and cyclo conducted by the Miami-Dade Water and Sewer Department stratigraphy were used to define a unique geologic framework in 1998 at the NWWF (fig. 2); earlier, Cunningham and others for the rocks that compose the Biscayne aquifer in north-central (2004b) evaluated additional samples in the general study area. Miami-Dade County. Lithostratigraphy is the description and The subsequent discussions summarize results from the two systematic organization of rocks and sediments into distinc- test coreholes, and appendix III presents detailed information tively named units based on the lithologic character of the on the mollusks found in specific samples. rocks and sediments and their stratigraphic relations (Jackson, 1997). Molluscan and foraminiferal paleontology were useful Stratigraphic Age and Paleoenvironments from in helping to establish paleoenvironments and environmental facies. Lithofacies is a mappable subdivision based on the Test Corehole near S‑3168 mineralogic, petrographic, and paleontologic characteristics The samples from the test corehole near well S‑3168 of rocks and sediments (Jackson, 1997). Depositional environ- contain few diagnostic molluscan species. All of the identi- ments are: (1) geographically restricted areas where a sediment fied species range in age from Pliocene to Holocene. accumulates (or has accumulated), (2) described in geomorphic The invertebrate assemblages in the core indicate an outer terms, and (3) characterized by physical, chemical, and bio- estuarine or shallow shelf paleoenvironment, with salinities logical conditions; for example, a marsh, lagoon, or shallow- ranging from 25 to 36 ppt (for example, figs. 5A-C and 6A). marine shelf. Cyclostratigraphy is defined here as the analysis Turbo castanea (fig. 6B) and Astralium phoebium? indicate of several-foot-scale depositional cycles, defined similarly by the presence of seagrass in the samples from 56 ft 10 in. James (1979) as upward-shallowing cycles (but herein including to 56 ft 6 in. and from 57 ft 3 in. to 57 ft (Abbott, 1974). aggrading cycles), and deposited on ancient carbonate shelves The images and description of selected Pelecypoda and and ramps. Even though some of the cycles reported herein have Gastropoda species are shown in figures 5 and 6, respectively. a chronostratigraphic significance (Perkins, 1977; Multer and others, 2002; Hickey, 2004), “cyclostratigraphy” is generally used herein to describe any regular repetition of lithofacies in a Stratigraphic Age and Paleoenvironments from carbonate succession (Harris and others, 1999, p. 3) and not in Test Corehole near S‑3170 the strict sense as to its application to geochronology as defined by Hilgen and others (2004). The lowermost sample (95 ft 7 in. to 95 ft) of the test corehole near well S‑3170 seems to be Pliocene in age on the Lithostratigraphy basis of the few mollusks that can be positively identified. Terebra aclinica has been reported to be present only in the Lithostratigraphic units of interest in this study (fig. 3) Pinecrest beds of the Tamiami Formation (Olsson, 1967). are contained in the Biscayne aquifer and include the Tamiami Cymatoica marcottae, a rare and distinctive clam found in Formation, Anastasia Formation, Key Largo Limestone, Fort the sample, was named from a “St. Petersburg fossil bed” by Thompson Formation, Miami Limestone, Pamlico Sand, Olsson and Petit (1964); however, the formation was not iden- and Lake Flirt Marl (Parker and Cooke, 1944; Causaras, tified. Numerous Cyclocardia are present in the sample that 1987; Fish and Stewart, 1991). In the present study area, the bears a strong resemblance to Cyclocardia granulata (Pliocene Biscayne aquifer was interpreted to comprise mostly the Fort to early Pleistocene age), but the coarse granular texture of the Thompson Formation, Miami Limestone, and Holocene peats sample prevented a positive identification. Chione specimens and marls. These lithostratigraphic units and the uppermost present in the sample do not seem to be typical Chione cancel- Tamiami Formation are the focus of this study. The lithology, lata, common in the overlying sediments of the core, but bear limiting extent, and thickness of lithostratigraphic units were a closer resemblance to Chione procancellata reported from determined by examination of continuously drilled cores and the “Cancellaria Zone” by Mansfield (1932). These samples borehole-geophysical logs (especially digital optical borehole correspond to the lowermost lithologic samples collected at images). Graphical displays of lithologic core descriptions the G‑3773 test corehole (fig. 1) and suggest that the upper- prepared for this study are presented in appendix I. most part of the Tamiami Formation sampled in test coreholes in the study area is equivalent to the Pinecrest Sand Member Molluscan Paleontology of the Tamiami Formation (fig. 3) reported as Pliocene age by The stratigraphic age of the Tamiami Formation was Scott (2001). Samples from 70 ft 5 in. to 70 ft and from 58 ft assessed in the one sample collected from the test corehole 6 in. to 58 ft 4 in. do not contain any mollusks that would be adjacent to well S‑3170 (fig. 2), and the paleoenvironments useful in distinguishing a Pleistocene verses a Pliocene age. 1 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
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The sample from 52 ft 9 in. to 52 ft 5 in. contains A Chione cancellata (Linnaeus, 1767). External mold relatively diverse molluscan fauna. The identified specimens from sample collected at 56 feet 10 inches to 56 feet range in age from Pliocene to Holocene. Several species 6 inches in a test corehole adjacent to well S-3168, (Chione cancellata (fig. 5 D), Dosinia elegans (fig. 5E-F), HFC2c2. and Phacoides (Bellalucina) waccamawensis (fig. 5J) have been reported from the Caloosahatchee, Bermont, and Fort B Dosinia sp. cf. Dosinia elegans (Conrad, 1843). Thompson Formations (for example, DuBar, 1958; Portell and Articulated external mold from sample collected at others, 1992). Conversely, Divaricella compsa (fig. 5G‑H) 56 feet 10 inches to 56 feet 6 inches in a test corehole ranges only from Pliocene to Pleistocene, and Turritella api- adjacent to well S-3168, HFC2c2. calis (fig. 6C) is reported only from Pliocene age beds presum- ably from the Caloosahatchee Formation (Mansfield, 1939; C Nuculana sp. External mold from sample collected at DuBar, 1958). The occurrence of Turritella apicalis seems 72 feet 5 inches to 72 feet 0 inches in a test corehole to restrict this sample to the Pliocene; however, it is possible adjacent to well S-3168, HFC2a. that either the sample needs to be reworked or the range of the species needs to be extended. The latter seems probable because data reported by Cunningham and others (2004b) D Chione cancellata (Linnaeus, 1767). External mold indicate that its highest occurrence within the Fort Thompson from sample collected at 52 feet 9 inches to 52 feet Formation is in HFC2g3 at test corehole G‑3732, an occur- 5 inches in a test corehole adjacent to well S-3170, rence presumably well within the Pleistocene (Multer and HFC2c2. others, 2002). The occurrence of Anadara aequalitas (fig. 5I) at 47 ft 4 in. to 46 ft 6 in. within HFC2d may place this sample E Dosinia sp. cf. Dosinia elegans (Conrad, 1843). Exter- in the lower Pleistocene because it has not been reported from nal mold from sample collected at 52 feet 9 inches to above the Bermont formation (informal) (DuBar, 1958; Olsson 52 feet 5 inches in a test corehole adjacent to well and Harbison, 1953; Olsson and Petit, 1964). This occurrence S-3170, HFC2c2. suggests the lower part of the Fort Thompson Formation below HFC2d1 could be assigned to the lower Pleistocene, contrary F Dosinia sp. cf. Dosinia elegans (Conrad, 1843). to assignment of the Fort Thompson Formation to the late Internal mold from sample collected at 52 feet 9 Pleistocene (Scott, 2001; Multer and others, 2002). There are inches to 52 feet 5 inches in a test corehole adjacent no chronostratigraphic data (for example, microfossil tax- to well S-3170, HFC2c2. onomy) herein, however, to corroborate an early Pleistocene age assignment to the lower Fort Thompson Formation. G-H Divaricella compsa (Dall, 1903). External molds from Most molluscan species that occur in the samples from sample collected at 52 feet 9 inches to 52 feet 5 40 ft 4 in. to 39 ft 6 in. and from 28 ft 4 in. to 27 ft range inches in a test corehole adjacent to well S-3170, in age from Pliocene to Holocene (fig. 5J-K and 6D-F). HFC2c2. The exception is Lithopoma americanum (fig. 6G) in the sample from 40 ft 4 in. to 39 ft 6 in. No published records of fossil occurrence of this species could be found, indicating its I Anadara aequalitas (Tucker and Wilson, 1932). Internal mold from sample collected at 47 feet 4 range needs to be extended. The two uppermost samples in the inches to 46 feet 6 inches in a test corehole adjacent test corehole adjacent to well S‑3170 (27 ft to 26 ft 10 in. and to well S-3170, HFC2c2. 20 ft 3 in. to 19 ft 6 in.) contain very few recognizable species, ranging in age from Pliocene or Pleistocene to Holocene. The molluscan species present indicate an outer estuarine J Phacoides (Bellucina) waccamawensis (Dall, 1903). External mold from sample collected at 40 feet 4 to shallow shelf paleoenvironment with a salinity range of inches to 39 feet 6 inches in a test corehole adjacent 25 to 35 ppt. Beginning with the sample at about 70 ft 5 in. to well S-3170, HFC2e2. to 70 ft to the uppermost sample in the test corehole adjacent to well S‑3170 (app. III), the mollusks are evidence of a very shallow, sandy or muddy bottom. Parastarte triquetra com- K Anodontia alba (Link, 1807). Articulated eternal mold monly are found on mudbanks and sandbars (Warmke and from sample collected at 40 feet 4 inches to 39 feet Abbott, 1962; Abbott, 1974). As noted in the present study 6 inches in a test corehole adjacent to well S-3170, and by Perry and Schwengel (1955), the presence of seagrass HFC2e2. is indicated by Turbo castanea in the sample from 52 ft 9 in. to 52 ft 5 in. The assemblages in the samples from 46 ft 6 in. to 26 ft 10 in. indicate mixed hard-bottom communities with Figure 5 (left). Selected Pelecypoda from core samples. Scale infaunal sand dwellers (Anodontia alba, Codakia orbicularis); bars are shown with each specimen. mollusks that live in or on sponges, corals, or ascidians 1 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
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(arcids, Lithopoma americanum, Vermicularia spirata); and Lithofacies and Depositional Environments epiphytic mollusks (Turbo castanea, Modulus modulus, Cerithium sp.) that indicate the presence of seagrass as noted Lithofacies and vertical lithofacies successions (Kerans in the present study and by Abbott (1974). and Tinker, 1997) are the two principal lithostratigraphic elements identified in this study. A lithofacies is a lateral Foraminiferal Paleontology mappable subdivision of a designated stratigraphic unit, distin- guished from adjacent subdivisions on the basis of lithology, The occurrence of stratigraphically important fora- including all mineralogic and petrographic characters and miniferal taxa and other allochems (mollusks, ostracodes, those paleontologic characters that influence the appearance, echinoids, red algae, and charophytes) identified in the 215 composition, or texture of the rock (Jackson, 1997). A vertical thin sections obtained from the Tamiami Formation, Fort lithofacies succession is a distinct stack of lithofacies that Thompson Formation, and Miami Limestone is presented in records upward shallowing or an amalgamation of a persistent table 2. From these thin sections, seven major foraminiferal environment as accommodation fills within a cycle-scale rela- biofacies (table 3) were recognized that assisted in definition tive sea-level rise (Kerans and Tinker, 1997). Lithofacies were in depositional environments. Key foraminiferal taxa are arranged into vertical lithofacies successions that represent shown in figure 7. either upward-shallowing units or units composed entirely or mostly of a distinct lithofacies representative of a single pre- vailing depositional water depth. Assessment of sedimentary characteristics and paleontology of lithofacies, their vertical A Turritella subannulata (Heilprin, 1887). External mold arrangement within vertical lithofacies successions, and their from sample collected at 72 feet 5 inches to 72 feet relation to bounding surfaces of the successions produced 0 inches in a test corehole adjacent to well S-3168, inferred major depositional environments. HFC2a.
B Turbo castanea (Gmelin, 1791). External mold from Lithofacies sample collected at 56 feet 10 inches to 56 feet 6 inches in a test corehole adjacent to well S-3168, Lithofacies are the fundamental descriptive rock HFC2c2. components of this study. Sixteen lithofacies delineate the sedimentary rocks that form the Fort Thompson Formation and C Turritella apicalis (Heilprin, 1886). External mold Miami Limestone in the study area. Many of the lithofacies from sample collected at 52 feet 9 inches to 52 feet may be composed of a substantial amount of quartz sand grains 5 inches in a test corehole adjacent to well S-3170, (generally less than 50 percent). In this case, “sandy” is added HFC2c2. as a prefix to the lithofacies type on plates 1 to 4. “Touching vugs,” a prefix to a lithofacies type, refers to vuggy porosity D Modulus modulus (Linnaeus, 1758). External mold that forms an interconnected pore system (Lucia, 1999). from sample collected at 40 feet 4 inches to 39 feet The 16 lithofacies include: (1) peloid packstone and grain- 6 inches in a test corehole adjacent to well S-3170, stone, (2) peloid wackestone and packstone, (3) Planorbella HFC2e2. floatstone and rudstone, (4) gastropod floatstone and rudstone, (5) conglomerate, (6) autobreccia, (7) pedogenic limestone E Cerithium sp. cf. Cerithium vicinia (Olsson and (laminated calcrete, massive calcrete, and root-mold limestone), Harbison, 1953). External mold from sample collected (8) mudstone and wackestone, (9) laminated peloid packstone at 40 feet 4 inches to 39 feet 6 inches in a test core- and grainstone, (10) skeletal packstone and grainstone, hole adjacent to well S-3170, HFC2e2. (11) coral framestone, (12) pelecypod floatstone and rud- stone, (13) touching‑vug pelecypod floatstone and rudstone, F Oliva sp. External mold from sample collected at (14) vuggy wackestone and packstone, (15) quartz sandstone 40 feet 4 inches to 39 feet 6 inches in a test corehole and skeletal quartz sandstone, and (16) quartz sand (table 4). adjacent to well S-3170, HFC2e2. Cunningham and others (2004b) provide detailed descrip- tions of most of these lithofacies and inferred environments G Lithopoma americanum (Gmelin, 1791). External mold of deposition, although some lithofacies terminology and from sample collected at 40 feet 4 inches to 39 feet definition of depositional environments are modified herein 6 inches in a test corehole adjacent to well S-3170, (table 4). For example, Planorbella floatstone and rudstone is HFC2e2. added to the present study. The three principal lithofacies that typically have the relatively highest yield of ground-water flow into or out of wellbores are peloid packstone and grainstone, Figure 6 (left). Selected Gastropoda from core samples. Scale laminated peloid packstone and grainstone, and touching‑vug bars are shown with each specimen. pelecypod floatstone and rudstone. 1 Table 2. Occurrence of stratigraphically important benthic foraminiferal taxa and other allochems in selected test coreholes.
[Sample depth, in feet below land surface. Biofacies 1, foraminifera absent (commonly contains smoothed-walled ostracods, commonly together with gastropods); biofacies 2, Ammonia predominant; biofacies 3, A
Elphidium predominant; biofacies 4, miliolids predominant; biofacies 5, archaiasinids, soritids, and peneroplids predominant; and biofacies 6, amphisteginids predominant. Annotations: X, present; ?, presence is Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla. questionable; X, predominant foraminiferal taxa; HFC, high-frequency cycle; TF, Tamiami Formation; forams, foraminifers]
Local well Sample HFC/Fm Lithofacies iden- depth tifier Bryozoans Charophytes Biofacies Rotaliform forams Rotalia Ammonia Elphidium Miliolids Soritids Sorites Parasorites Archaiasinids Archaias Androsina Cyclorbiculina Cycloputeolina Peneroplids Peneroplis Bolivinids Bolivina Gypsina Nonion Amphisteginids Globigerinids Spaerogypsina Agglutinating forams Mollusks Gastropods Bivalves Ostracods Echinoids Red Algae G-3678 23.4 HFC3a Planorbella floatstone/rudstone 1 X X 24.80 HFC2h Mudstone/wackestone 1-2 X X X X 33.3 HFC2g3 Mudstone/wackestone 1 X G-3679 15.6 HFC3a Mudstone/wackestone 1 X? X 27.1 HFC2h Mudstone/wackestone 3? X X F 35.7 HFC2g3 Mudstone/wackestone 1 X X G-3681 14.9 HFC3b Mudstone/wackestone 2-3 X X X X G-3683 13.1 HFC4 Peloid wackestone/packstone - X G-3684 16.0 HFC4 Peloid wackestone/packstone - 16.4 HFC4 Peloid wackestone/packstone 5 X X X 17.4 HFC3b Mudstone/wackestone 2 F F X 19.8 HFC3b Skeletal packstone/grainstone 5 X X 22.0 HFC3a Mudstone/wackestone 1?-2 X? X X 23.2 HFC3a Pelecypod floatstone/rudstone 5 X X 27.2 HFC3a Pelecypod floatstone/rudstone 5 X X 30.7 HFC3a Touching-vug pelecypod floatstone/rudstone - X 31.5 HFC2h Skeletal packstone/grainstone 5 X X G-3685 28.5 HFC2h Skeletal packstone/grainstone 1? X G-3687 14.2 HFC3a Mudstone/wackestone 4-5 X X X 15.5 HFC3a Skeletal packstone/grainstone 4-5 X X 16.5 HFC3a Skeletal packstone/grainstone 4-5 X X 17.5 HFC3a Skeletal packstone/grainstone 5 X 18.8 HFC3a Touching-vug pelecypod floatstone/rudstone 1? X 21.1 HFC3a Planorbella floatstone/rudstone - X X? 24.1 HFC2h Skeletal packstone/grainstone 2 X 25.6 HFC2h Pelecypod floatstone/rudstone 2 X G-3733 49.94 HFC2c2 Very sandy pelecypod floatstone/rudstone 4-5 X X 53.28 HFC2c2 Skeletal quartz sandstone 6? X G-3770 71.00 Tamiami Fm Mudstone/wackestone 2-3 X X X X G-3772 11.89 HFC3b Pedogenic limestone 5 X X X X X 14.03 HFC3a Planorbella floatstone/rudstone 1 X X X X G-3772 14.95 HFC3a Planorbella floatstone/rudstone 1 X X X 15.60 HFC3a Mudstone/wackestone 5 X X X Table 2. Occurrence of stratigraphically important benthic foraminiferal taxa and other allochems in selected test coreholes. (Continued)
Local well Sample HFC/Fm Lithofacies iden- depth tifier Biofacies Rotaliform forams Rotalia Ammonia Elphidium Miliolids Soritids Sorites Parasorites Archaiasinids Archaias Androsina Cyclorbiculina Cycloputeolina Peneroplids Peneroplis Bolivinids Bolivina Gypsina Nonion Amphisteginids Globigerinids Spaerogypsina Agglutinating forams Mollusks Gastropods Bivalves Ostracods Echinoids Red Algae Bryozoans Charophytes 16.06 HFC3a Conglomerate 4? X? X X X Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer 16.36 HFC3a Mudstone/wackestone 3? X? X 17.20 HFC3a Skeletal packstone/grainstone 3-5? X X X X X X X 18.03 HFC3a Pelecypod floatstone/rudstone 5 X X X X X X X? X X 19.70 HFC3a Pelecypod floatstone/rudstone 4-5 X X X 21.47 HFC3a Touching-vug pelecypod floatstone/rudstone 5 X X X 22.30A HFC3a Planorbella floatstone/rudstone 1 X X X 22.30B HFC3a Planorbella floatstone/rudstone 1 X X X 22.89 HFC2h Skeletal packstone/grainstone 5 X X X X X 23.14 HFC2h Skeletal packstone/grainstone 3-4 X X X X X X X 23.55 HFC2h Skeletal packstone/grainstone 3-5 X X X X X X 25.35 HFC2h Pelecypod floatstone/rudstone 4-5 X X X X X X X 27.35 HFC2g3 Pelecypod floatstone/rudstone 5 X X X X X 28.27 HFC2g3 Pelecypod floatstone/rudstone 4?-5? X X X X X X 28.77 HFC2g3 Pelecypod floatstone/rudstone 5 X X? X X X X X X X 29.69 HFC2g3 Pelecypod floatstone/rudstone 3-5? X X X X X 30.47 HFC2g2 Sandy skeletal packstone/grainstone 3-5? X X X X X X 31.15 HFC2g2 Skeletal packstone/grainstone 3 X X X X X X 31.65 HFC2g2 Skeletal packstone/grainstone 3-4 X X X X X X 31.98 HFC2g2 Skeletal packstone/grainstone 3-5? X X X X X X 32.90 HFC2g2 Pelecypod floatstone/rudstone 5 X X X X X X 33.73 HFC2g1 Planorbella floatstone/rudstone 3-5? X X X X X 33.95 HFC2g1 Planorbella floatstone/rudstone 1?-5? X X X 34.32 HFC2g1 Pelecypod floatstone/rudstone 4 X X X X 34.49 HFC2g1 Pelecypod floatstone/rudstone 3 X X X X X 34.53 HFC2g1 Pelecypod floatstone/rudstone 3-5 X X X X X X X 36.49 HFC2e2 Sandy pelecypod floatstone/rudstone 3-5 X X X 37.57 HFC2e2 Sandy pelecypod floatstone/rudstone 3-5 X X X X X X 38.24 HFC2e2 Sandy pelecypod floatstone/rudstone 3-5 X X X X 41.97 HFC2d Skeletal packstone/grainstone 1?-3?-5? X X X X X X 42.26 HFC2d Skeletal packstone/grainstone 5 X X X X X X X 42.65 HFC2d Skeletal packstone/grainstone 1-4? X X X X X X 42.98 HFC2d Skeletal packstone/grainstone 5 X X X X X X X
43.98 HFC2d Skeletal packstone/grainstone 4-5 X X X X 44.90 HFC2d Skeletal packstone/grainstone 5 X X X X 1
46.13 HFC2d Sandy Planorbella floatstone/rudstone 2-3 X X X X 9 2 0
Table 2. Occurrence of stratigraphically important benthic foraminiferal taxa and other allochems in selected test coreholes. (Continued) A
Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Local well Sample HFC/Fm Lithofacies iden- depth tifier Biofacies Rotaliform forams Rotalia Ammonia Elphidium Miliolids Soritids Sorites Parasorites Archaiasinids Archaias Androsina Cyclorbiculina Cycloputeolina Peneroplids Peneroplis Bolivinids Bolivina Gypsina Nonion Amphisteginids Globigerinids Spaerogypsina Agglutinating forams Mollusks Gastropods Bivalves Ostracods Echinoids Red Algae Bryozoans Charophytes G-3772 46.88 HFC2d Skeletal sandstone 2-3 X X X X 47.20 HFC2d Skeletal sandstone 2 X X X X 51.60 HFC2c2 Sandy pelecypod floatstone/rudstone 2-4 X X X X X X 51.89 HFC2c2 Sandy pelecypod floatstone/rudstone 2-5 X X X X X 52.49 HFC2c2 Sandy pelecypod floatstone/rudstone 3-5 X X X? X X 52.99 HFC2c2 Sandy pelecypod floatstone/rudstone 4-5 X X X X X X 54.66 HFC2c2 Sandy pelecypod floatstone/rudstone? 4 X X X X X X X 57.85 HFC2c2 Sandy pelecypod floatstone/rudstone 5 X X X X X 58.29 HFC2c2 Sandy pelecypod floatstone/rudstone 2 X X X 58.62 HFC2c2 Sandy pelecypod floatstone/rudstone 2 X X X X X 58.90 HFC2b Sandy pelecypod floatstone/rudstone 2 X X X 59.20 HFC2b Sandy skeletal packstone/grainstone 2-3 X X X X X 60.12 HFC2b Sandy skeletal packstone/grainstone 4 X 60.43 HFC2b Sandy pelecypod floatstone/rudstone 4? X X X X 61.51 HFC2b Sandy pelecypod floatstone/rudstone 5 X X X X X 64.69 HFC2a Sandy pelecypod floatstone/rudstone 5 X X X X X X 65.77 HFC2a Sandy pelecypod floatstone/rudstone 5 X X X X X X 66.90 HFC2a Sandy skeletal packstone/grainstone 3-5 X X X X X X X X 67.31 HFC2a Sandy skeletal packstone/grainstone 5/3 X X X X X X 67.70 HFC2a Sandy skeletal packstone/grainstone 5? X X X X X X 67.86 HFC2a Sandy skeletal packstone/grainstone 5 X X X X? 68.61 HFC2a Sandy skeletal packstone/grainstone 5 X X X X X 70.20 HFC2a Sandy conglomerate 2-5 X X X X? X X 70.87 HFC2a Sandy conglomerate 6? X X X 70.9 HFC2a Sandy conglomerate 3 X X X X 71.6 HFC2a Sandy conglomerate 3-4 X X X 72.88 HFC2a Sandy conglomerate ? X X? X 73.03 HFC2a Sandy conglomerate ? X X 73.86 HFC2a Sandy conglomerate 6? X X X? X X 74.2 Tamiami Fm Sandy conglomerate 3 X X X 75.00 Tamiami Fm Sandy conglomerate? 6 X X X X G-3779 16.17 HFC5 Peloid packstone/grainstone 4 X X X 17.17 HFC5 Peloid packstone/grainstone 4 X X 18.20 HFC5 Peloid packstone/grainstone 4 X X X X 21.87 HFC3b Mudstone/wackestone 2 X X X X 21.93 HFC3b Mudstone/wackestone 2? X? X X X Table 2. Occurrence of stratigraphically important benthic foraminiferal taxa and other allochems in selected test coreholes. (Continued)
Local well Sample HFC/Fm Lithofacies iden- depth tifier Bryozoans Charophytes Biofacies Rotaliform forams Rotalia Ammonia Elphidium Miliolids Soritids Sorites Parasorites Archaiasinids Archaias Androsina Cyclorbiculina Cycloputeolina Peneroplids Peneroplis Bolivinids Bolivina Gypsina Nonion Amphisteginids Globigerinids Spaerogypsina Agglutinating forams Mollusks Gastropods Bivalves Ostracods Echinoids Red Algae Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer 22.41 HFC3b Mudstone/wackestone 2-5? X X X X X X 23.45 HFC3b Pedogenic limestone (crumbly mudstone) 2-3 X X X 24.30 HFC3b Skeletal packstone/grainstone 2-4? X X X X G-3779 25.45 HFC3b Skeletal packstone/grainstone 4-5 X X X X 26.53 HFC3b Pelecypod floatstone/rudstone 5 X X X X X X 26.70 HFC3b Pelecypod floatstone/rudstone 5 X X X? X 27.50 HFC3a Planorbella floatstone/rudstone 1 X X X 29.74 HFC3a Laminated peloid packstone/grainstone 3-4? X X X 30.80 HFC3a Pelecypod floatstone/rudstone 3-4 X X X X 34.98 HFC3a Planorbella floatstone/rudstone 1 X X X 36.10 HFC3a Planorbella floatstone/rudstone 1 X X X 38.55 HFC2h Skeletal packstone/grainstone 2 X X X? X X X X 39.30 HFC2h Pelecypod floatstone/rudstone 3-5 X X? X X X X X 40.43 HFC2h Pelecypod floatstone/rudstone 5 X X X X X X X X 43.60 HFC2g3 Touching-vug pelecypod floatstone/rudstone 5 X X X X X X X 46.72 HFC2g2 Skeletal packstone/grainstone 3-5 X X X X X X 47.31 HFC2g2 Skeletal packstone/grainstone 5 X X X X X X 47.52 HFC2g2 Skeletal packstone/grainstone 5/1-1a X X X X X X 48.58 HFC2g2 Touching-vug pelecypod floatstone/rudstone 1-2 X X X X X X X X 49.02 HFC2f Skeletal wackestone/packstone 1 X X 49.71 HFC2f Skeletal wackestone/packstone 1 X X 51.94 HFC2f Planorbella floatstone/rudstone 1/3-6 X X X X X X 52.11 HFC2e2 Mudstone/wackestone 1 X X 52.65 HFC2e2 Mudstone/wackestone 1-2/3 X X X X X 53.97 HFC2e2 Touching-vug pelecypod floatstone/rudstone 3-5 X X X X X X X X 54.76 HFC2d Mudstone/wackestone 1 X 55.19 HFC2d Planorbella floatstone/rudstone 1/2-4? X X X 58.50 HFC2d Sandy pelecypod floatstone/rudstone 4-6 X X X X X 59.51 HFC2d Sandy pelecypod floatstone/rudstone 3? X X X 60.25 HFC2d Sandy pelecypod floatstone/rudstone 6? X X X X X X G-3782 43.30 HFC2e2 Mudstone/wackestone 1 X X G-3784 31.00 HFC3a Planorbella floatstone/rudstone 1 X X X G-3788 37.66 HFC2f Mudstone/wackestone 1 X X X 43.60 HFC2e1 Laminated calcrete 1 X X 1 Table 2. Occurrence of stratigraphically important benthic foraminiferal taxa and other allochems in selected test coreholes. (Continued) A
Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla. Local well Sample HFC/Fm Lithofacies iden- depth tifier Bryozoans Charophytes Biofacies Rotaliform forams Rotalia Ammonia Elphidium Miliolids Soritids Sorites Parasorites Archaiasinids Archaias Androsina Cyclorbiculina Cycloputeolina Peneroplids Peneroplis Bolivinids Bolivina Gypsina Nonion Amphisteginids Globigerinids Spaerogypsina Agglutinating forams Mollusks Gastropods Bivalves Ostracods Echinoids Red Algae Mixed mudstone/wackestone and gastropod G-3789 40.67 HFC2f 1 X X X floatstone/rudstone 48.80 HFC2e1 Skeletal packstone/grainstone 5? X X X X X 53.90 HFC2d Touching-vug pelecypod floatstone/rudstone 3? X X X with sandstone matrix G-3790 40.97 HFC2g2 Planorbella floatstone/rudstone 1 X X X 44.50 HFC2f Mudstone/wackestone 1/2-3 X X X X 50.02 HFC2e2 Mudstone/wackestone 1 X X 55.70 HFC2d Sandy pelecypod floatstone/rudstone 3 X X G-3791 16.60 HFC3b Mudstone/wackestone 2-3 X X X X 28.10 HFC3a Touching-vug pelecypod floatstone/rudstone 4 X X X 29.90 HFC3a Planorbella floatstone/rudstone 1 X X X X 35.55 HFC2h Sandy pelecypod floatstone/rudstone 1/2-3? X X X X 35.63 HFC2h Sandy pelecypod floatstone/rudstone 1 X X X 43.20 HFC2f Mudstone/wackestone 1/5? X X X X X 51.25 HFC2d Mudstone/wackestone 1/2-3? X X 53.50 HFC2d Sandy mudstone/wackestone 3 X X X 58.30 HFC2c2 Mudstone/wackestone 1?/3? X X X X 58.50 HFC2c2 Mudstone/wackestone 1 X X 58.60 HFC2c2 Mudstone/wackestone 1-4 X X X 63.35 Tamiami Fm Sandy gastropod floatstone 2 X X X X 75.60 Tamiami Fm Sandy pelecypod floatstone/rudstone 1 X 75.70 Tamiami Fm Sandy pelecypod floatstone/rudstone 5 X X X? X X X X 76.30 Tamiami Fm Sandy pelecypod floatstone/rudstone 6? X X X X X 76.60 Tamiami Fm Sandy pelecypod floatstone/rudstone 3? X X X? X X X X X G-3793 6.19 HFC3b Planorbella floatstone/rudstone 1 X X X 17.19 HFC2h Skeletal packstone 5 X X 21.25 HFC2h Laminated calcrete and skeletal packstone 3/4-5? X X X X X X 59.57 HFC2a Auto breccia wackestone mixed X X X X X X 63.92 Tamiami Fm Sandy pelecypod floatstone/rudstone 6 X X X 65.40 Tamiami Fm Sandy pelecypod floatstone/rudstone 6 X X X G-3794 19.35 HFC2h Skeletal packstone/grainstone 3-5 X X X X X X 63.10 Tamiami Fm Sandy pelecypod floatstone/rudstone 6 X X X X G-3795 17.57 HFC3a Burrowed wackestone 2-5 X X X X X 35.00 HFC2f Planorbella mudstone 1-3 X X X 59.00 Tamiami Fm Skeletal packstone/grainstone 2-3 X X X X X Table 2. Occurrence of stratigraphically important benthic foraminiferal taxa and other allochems in selected test coreholes. (Continued)
Local well Sample HFC/Fm Lithofacies iden- depth tifier Bryozoans Charophytes Biofacies Rotaliform forams Rotalia Ammonia Elphidium Miliolids Soritids Sorites Parasorites Archaiasinids Archaias Androsina Cyclorbiculina Cycloputeolina Peneroplids Peneroplis Bolivinids Bolivina Gypsina Nonion Amphisteginids Globigerinids Spaerogypsina Agglutinating forams Mollusks Gastropods Bivalves Ostracods Echinoids Red Algae
59.70 Tamiami Fm Skeletal packstone/grainstone 2-3 X X X X Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer Pelecypod floatstone/rudstone and skeletal 61.54 Tamiami Fm 5 X X X X X X packstone/grainstone 63.92 Tamiami Fm Pelecypod floatstone/rudstone 4? X X X X X S-31691 8.3 HFC5 Peloid packstone/grainstone 5 X 9.6 HFC5 Peloid packstone/grainstone ? X X 12.21 HFC3b Massive calcrete - S-31691 13.52 HFC3a Planorbella floatstone/rudstone 1-2 X X X 14.9 HFC3a Planorbella floatstone/rudstone 1 X X 20.2 HFC3a Mudstone/wackestone 3? X X X 22.5 HFC3a Mudstone/wackestone 1 X X X X 23.9 HFC3a Mudstone/wackestone 1 25.75 HFC2g3 Autobreccia 3-4 X X? X X X X 27.7 HFC2g3 Pelecypod floatstone/rudstone 4? X X? X X? X X X 28.9 HFC2g3 Skeletal wackestone/packstone 2-3 X X X X X 29.24 HFC2g3 Sandy skeletal packstone/grainstone 3-5 X X? X? X X 30.3 HFC2g2 Skeletal wackestone/packstone 3-5 X X X? X? X X X X 31.5 HFC2g2 Pelecypod floatstone/rudstone 3-5 X X X X X X Laminated calcrete and skeletal wackestone/ 33.27 HFC2e2 2-5 X? X X? X X packstone 35.2 HFC2e2 Sandy pelecypod floatstone/rudstone 3-5 X X? X X 36.3 HFC2e2 Sandy pelecypod floatstone/rudstone 4-5 X X X X X X 37.9 HFC2e2 Sandy pelecypod floatstone/rudstone 5? X? X X 40.2 HFC2d Sandy skeletal packstone 2-5? X X? X X X 42.1 HFC2d Sandy skeletal packstone 5? X? X? X X 43.0 HFC2d Sandy skeletal packstone 5 X X X? X X Sandy touching-vug pelecypod floatstone/ 47.0 HFC2d 5? X X X rudstone 47.2 HFC2c2 Sandy skeletal packstone 3 X X X X 48.1 HFC2c2 Sandy skeletal packstone 4-5 X X X X Sandy touching-vug pelecypod floatstone/ 50.2 HFC2c2 4 X X X rudstone 51.45 HFC2c2 Sandy skeletal grainstone 3-5 X X X X 52.45 HFC2c2 Sandy skeletal packstone 5 X X? X X
54.45 HFC2c2 Sandy pelecypod floatstone/rudstone 5? X X X X? X 55.5 HFC2c2 Sandy pelecypod floatstone/rudstone 3-5 X X X X X X X A
Local Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla. well Sample HFC/Fm Lithofacies iden- depth tifier Bryozoans Charophytes Biofacies Rotaliform forams Rotalia Ammonia Elphidium Miliolids Soritids Sorites Parasorites Archaiasinids Archaias Androsina Cyclorbiculina Cycloputeolina Peneroplids Peneroplis Bolivinids Bolivina Gypsina Nonion Amphisteginids Globigerinids Spaerogypsina Agglutinating forams Mollusks Gastropods Bivalves Ostracods Echinoids Red Algae 64.75 HFC2b Sandy pelecypod floatstone/rudstone 5 X X X 68.0 HFC2b Sandy pelecypod floatstone/rudstone 5? X X X? X X X 69.08 HFC2a Sandy skeletal packstone/grainstone 5 X? X? X X 70.09 HFC2a Sandy skeletal wackestone/packstone 5? X X X? X? X X X 70.9 HFC2a Sandy pelecypod floatstone/rudstone 5 X? X? X X 73.35 HFC2a Conglomerate 5 X X? X X X X 73.4 HFC2a Conglomerate 4? X X X 76.0 Tamiami Fm Sandy pelecypod floatstone/rudstone 4? X X 76.1 Tamiami Fm Sandy pelecypod floatstone/rudstone 4-6 X X X 76.2 Tamiami Fm Sandy pelecypod floatstone/rudstone 2 X? X X X X 1Test corehole adjacent to well S-3169.
Table 3. Foraminiferal biofacies and associated interpretive paleoenvironments.
Biofacies Principal foraminiferal genera Paleoenvironment
1 Foraminifera absent Freshwater; commonly contains smooth-walled ostracods and freshwater gastropods
2 Ammonia predominant Inner shelf and nearshore, in coastal bays, lagoons, and lower reaches of estuaries, having variable salinity values, commonly tidally influenced 3 Elphidium predominant Inner shelf and nearshore, in coastal bays, lagoons, and lower reaches of estuaries, having variable salinity values, but more normal salinity, open ocean 4 Miliolids predominant Marine shelf environments of normal to mildly hypersalinity, typically with grassy meadows and associated with areas of significant biogenic carbonate production. Depths can vary from about 3 to about 130 feet 5 Archaiasinids, soritids, peneroplids Marine shelf environments of normal to mildly hypersalinity, typically with grassy meadows and associated predominant with areas of significant biogenic carbonate production. Depths can vary from about 3 to about 130 feet 6 Amphisteginids predominant Amphisteginids range throughout shelf deposits to about 328 feet, but also on the margins of Holocene or relict Pleistocene carbonate buildups and platforms 7 Planktic foraminifera significant Indicative of open ocean conditions, possibly at the platform margin or over deeper parts of the shelf Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer
A B C D
E F G H
Depositional Environments A Ammonia sp. of biofacies 2 Lithofacies are the preserved part of ancient depositional B Elphidium sp. of biofacies 3 facies that are representative of ancient depositional environ- ments. In the study area, evaluation of the lithofacies of the C Miliolid of biofacies 4 uppermost Tamiami Formation, Fort Thompson Formation, and Miami Limestone (figs. 3 and 4) are indicative of six D Peneroplis sp. of biofacies 5 major depositional environments. In a generally regressive succession, from bottom to top, these include: (1) middle E Archaias sp. of biofacies 5 ramp, (2) platform margin-to-outer platform, (3) open-marine platform interior, (4) restricted platform interior, (5) brackish F Soritid of biofacies 5 platform interior, and (6) freshwater terrestrial environments (figs. 8 and 9). The presence of depositional environments G Amphistegina sp. of biofacies 6 2 to 6 is inferred for the Fort Thompson Formation; however, only the middle ramp and the open-marine platform interior H Planktics of biofacies 7 environments are representative of the uppermost Tamiami Figure 7. Thin-section photomicrographs of foraminifera Formation and Miami Limestone, respectively. The lithofacies characteristic of foraminiferal biofacies 2-7. An explanation associated with the open-marine platform interior depositional of biofacies relation to foraminiferal taxonomy is provided in environment typically have the relatively highest yield of table 3. ground-water flow into or out of wellbores. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Table 4. Summary of lithofacies of the Miami Limestone, Fort Thompson Formation, and selected lithofacies of the Tamiami Formation in north-central Miami-Dade County.
[NDA, No laboratory measurements available; *, lithology specific to Tamiami Formation]
Lithofacies Description
Color: Very pale orange 10YR 8/2, grayish orange 10YR 7/4 and pale yellowish orange 10YR 8/6 matrix Depositional texture: Burrow-mottled pelmold and peloid grainstone and packstone Sedimentary structures/textures: Highly burrowed, including minor callianassid shrimp burrows, very thickly bedded Carbonate and accessory grains: Mainly pelmolds and peloids; minor pelecypods, gastropods, oomolds, and Schizoporella bryo- Peloid packstone zoans, miliolids, quartz grains, intraclasts, archaiasinids, agglutinating foraminifera and grainstone Helium porosity (percent): Common pore types include pelmoldic, solution-enlarged burrow porosity, and root-mold porosity. Mean porosity is 44.5, n = 26, range from 37.2 to 49.4 Air permeability (millidarcies): Mean maximum horizontal is 9,187, n = 24, range from 1,116 to 25,764; mean vertical is 4,719, n = 26, range from 220 to 14,750 Paleoenvironment: Open marine platform interior
Color: Very pale orange 10YR 8/2, dark yellowish orange 10YR 6/6, moderate yellowish brown 10YR 5/4, pale yellowish brown 10YR 6/2, and light brown 5YR 5/6 matrix Depositional texture: Mainly mud-dominated fabric characterized by pelecypod, benthic foram lime floatstone with a peloid lime wackestone to mud-dominated lime packstone matrix, but minor grain-dominated fabric characterized by peloid lime grainstone or skeletal grain-dominated lime packstone matrix; minor solution-enlarged burrows filled with peloid grainstone or packstone Sedimentary structures/textures: Highly burrowed, including minor callianassid shrimp burrows, common ~0.5-1-mm-diameter Peloid wackestone rhizoliths and less common up to 5-cm wide subvertical root molds, medium to very thickly bedded and packstone Carbonate and accessory grains: Mainly peloids, pelecypods (including Chione) and benthic foraminifers (including archaiasi- nids, soritids, miliolids, peneroplids, Cyclorbiculina), ostracods, and minor Schizoporella bryozoans, quartz grains, and intraclasts Helium porosity (percent): Common pore types include pelmoldic and skeletal moldic porosity, separate- and touching-vug porosity, root-mold porosity, and intraparticle porosity. Mean porosity is 18.4, n = 12, range from 11.0 to 27.3 Air permeability (millidarcies): Mean maximum horizontal is 2,611, n = 12, range from 13.8 to 11,017; mean vertical is 596, n = 12, range from 11 to 1,750 Paleoenvironment: Open-marine platform interior
Color: Pale yellowish brown 10YR 6/2, very pale orange 10YR 8/2, light gray N7 to medium dark gray N4 Depositional texture: Moldic gastropod floatstone and rudstone with skeletal wackestone and packstone matrix; local lime wackestone Sedimentary structures/textures: ~0.5-1-mm diameter rhizoliths, local desiccation cracks, very thinly to very thickly bedded Carbonate and accessory grains: Mainly gastropod molds including Planorbella, Pomacea, Physa, Hydrobiidae?, smooth-walled Planorbella floatstone ostracods, and skeletal fragments; minor quartz sand, pelecypods, freshwater-algae Charophyta, uncommon benthic foraminifera and rudstone (including Ammonia, Elphidium, peneroplids), echinoids Helium porosity (percent): Common pore types include skeletal-moldic separate vugs, solution-enlarged semivertical root molds, minor vertical or irregular vugs and local root-mold porosity. Mean porosity is 21.8, n = 31, range from 13.0 to 41.5 Air permeability (millidarcies): Mean maximum horizontal is 3,458, n = 31, range from 0.02 to 19,323; mean vertical is 5,354, n = 30, range from 1 to 17,428 Paleoenvironment: Freshwater terrestrial (mainly freshwater ponds or marshes)
Color: Very pale orange 10YR 8/2 Depositional texture: Moldic gastropod floatstone and rudstone with skeletal wackestone and packstone matrix; local lime wackestone Sedimentary structures/textures: Thinly to medium bedded Gastropod floatstone Carbonate and accessory grains: Mainly gastropods molds including skeletal fragments; minor quartz sand, pelecypods, ostracods and rudstone Helium porosity (percent): Common pore types include skeletal-moldic separate vugs and minor irregular vugs. Mean porosity is 20.8, n = 4, range from 11.2 to 29.7 Air permeability (millidarcies): Mean maximum horizontal is 1,101, n =4, range from 43 to 2,350; mean vertical is 3,775, n = 4, range from 317 to 13,272 Paleoenvironment: Restricted platform interior Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer
Table 4. Summary of lithofacies of the Miami Limestone, Fort Thompson Formation, and selected lithofacies of the Tamiami Formation in north-central Miami-Dade County. (Continued)
Lithofacies Description
Color: Very pale orange 10YR 8/2 and pale yellowish brown 10YR 6/2 matrix, and very pale orange 10YR 8/2, dark yellowish orange 10YR 6/6, moderate yellowish brown 10YR 5/4, pale yellowish brown 10YR 6/2, moderate brown 5YR 4/4, light brown 5YR 6/4, grayish orange pink 5YR 7/2 and dark gray N3 to light gray N7 intraclasts Depositional texture: Intraclast lime rudstone with quartz sandstone matrix or quartz sand-rich lime grainstone or mud-dominated lime packstone matrix Sedimentary structures/textures: Common ~0.5-1-mm diameter rhizoliths, thinly to medium bedded Conglomerate Carbonate and accessory grains: Mainly intraclasts and quartz grains; local minor peloids, pelecypods, gastropods, echinoids, and benthic foraminifera (including Elphidium, Ammonia, miliolids, soritids, rotaliforms, amphistiginids, Nonion) Helium porosity (percent): Common pore types include intergrain porosity, separate- and touching-vug porosity, and local root- mold porosity. Mean porosity is 15.5, n = 10, range from 6.9-26.0 Air permeability (millidarcies): Mean maximum horizontal is 968, n = 10, range from 1-3,813; mean vertical is 1,009, n = 10, range from 0-5,624 Paleoenvironment: Freshwater terrestrial (fluvial?), restricted platform interior (shoreface?), platform margin-to-outer platform
Color: Very pale orange 10YR 8/2 and light gray N7 Depositional texture: Angualar clasts forming a rudstone Sedimentary structures/textures: Commonly thinly to medium bedded Carbonate and accessory grains: Mostly autoclasts, fossils include mollusks, ostracods, echinoids, benthic foraminifera (including Ammonia, archaiasinids?, miliolids, soritids, rotaliforms, bolvinids, Spaerogypsina, amphistiginids) Autobreccia Helium porosity (percent): Common pore types include minor microporosity; interclast porosity, and vuggy porosity. Mean porosity is NDA Air permeability (millidarcies): Mean maximum horizontal is NDA and mean vertical is NDA Paleoenvironment: Subaerial exposure
Color: (1) Very pale orange 10YR 8/2, dark yellowish orange 10YR 6/6, moderate yellowish brown 10YR 5/4, pale yellowish brown 10YR 6/2 and grayish orange 10YR 7/4; (2) very pale orange 10YR 8/2 and grayish orange 10YR 7/4; and (3) dark yellowish orange 10YR 6/6, grayish orange 10YR 7/4, pale yellowish brown 10YR 6/2, moderate yellowish brown 10YR 5/4 and very pale orange 10YR 8/2 Depositional texture: Three principal types: (1) laminated calcrete, (2) massive calcrete, and (3) root-mold limestone Sedimentary structures/textures: (1) Thinly to very thickly bedded and drapes over microtopography; (2) very finely laminated; and (3) thinly to very thickly bedded or poorly bedded, desiccation cracks Pedogenic Carbonate and accessory grains: (1) Minor quartz grains, uncommon miliolids, ostracods; (2) minor intraclasts, pelecypods, limestone skeletal fragments, quartz grains, benthic foraminifera including Ammonia, Elphidium, miliolids, soritids, arachaiasinids, penero- plids, rotaliforms; and (3) skeletal fragments and local miliolids, minor quartz sand Helium porosity (percent): (1) Minor microporosity; (2) 20 to 30 percent root-mold porosity, 5 to 10 percent vuggy porosity, 5 percent pelmoldic and skeletal moldic porosity; and (3) 2 to 5 percent skeletal moldic porosity, 2 to 5 percent desiccation crack porosity Air permeability (millidarcies): (1) Low, (2) moderate to high, and (3) matrix very low to low Paleoenvironment: Subaerial exposure
Color: Very pale orange 10YR 8/2, grayish orange pink 5YR 7/2, pale yellowish brown 10YR 6/2, grayish orange 10YR 7/4 Depositional texture: Lime mudstone and wackestone Sedimentary structures/textures: Common subvertical cracks, ~0.5 to 1 mm diameter rhizoliths, semivertical solution-enlarged vugs, thinly to thickly bedded Carbonate and accessory grains: (1) Brackish: mainly ostracods, skeletal fragments, gastropods (including Planorbella in Mudstone and the G-3679 test corehole), benthic foraminifers (including Ammonia, Elphidium, miliolids, soritids, archaiasinids, peneroplids, Androsina, rotaliforms); minor pelecypods quartz sand, charophytes; and (2) mud mound: peloids, pelecypods, benthic foraminifers wackestone (including miliolids), quartz sand, intraclasts, ostracods Helium porosity (percent): Common pore types include skeletal mold porosity, root-mold porosity, separate vug porosity, semivertical touching-vug porosity, and desiccation-crack porosity. Mean porosity is 15.7, n = 50, range from 5.5 to 31.1 Air permeability (millidarcies): Mean maximum horizontal is 2,292, n = 49, range from 0.001 to 20,592; mean vertical is 1,880, n = 50, range from 0 to 18,223 Paleoenvironment: Brackish platform interior A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Table 4. Summary of lithofacies of the Miami Limestone, Fort Thompson Formation, and selected lithofacies of the Tamiami Formation in north-central Miami-Dade County. (Continued)
Lithofacies Description
Color: Very pale orange 10YR 8/2 Depositional texture: Peloid grainstone and packstone Sedimentary structures/textures: Thinly laminated to very thinly bedded Laminated peloid Carbonate and accessory grains: Mainly peloids; minor quartz grains, skeletal fragments, and benthic foraminifers (including packstone and miliolids, Elphidium, archaiasinids, Androsina, rotaliforms), mollusk fragments grainstone Helium porosity (percent): Common pore types include moldic porosity, intergrain porosity, and bedding plane vug porosity. Mean porosity is 20.2, n = 1 Air permeability (millidarcies): Mean maximum horizontal is 5,268, n = 1; mean vertical is 533, n = 1 Paleoenvironment: Restricted platform interior (tidal flat)
Color: Very pale orange 10YR 8/2, pale yellowish brown 10YR 6/2, grayish orange 10YR 7/4; light gray N7 to very light gray N8 Depositional texture: Skeletal grainstone and packstone Sedimentary structures/textures: Principally massive and highly burrowed, thickly to very thickly bedded Carbonate and accessory grains: Mainly skeletal fragments, benthic foraminifers (including archaiasinids, soritids, miliolids, peneroplids, Elphidium, Ammonia, Androsina, Amphistegina, rotaliforms, Gypsina, Parasorites, Cyclorbiculina, Cycloputeolina), Skeletal packstone peloids, mollusks (including Chione, Modulus, Turritella, Codakia, Lucina, Trachycardium, Anodontia, Lirophora, Pyrazisinus, Tagelus, Anomalocardia, Melongena, Lucinisca, Carditimera, Codakia, Cerithium), skeletal fragments, peloids, ostracods, gastro- and grainstone pods, echinoids; minor to abundant quartz grains; trace red algae, bryozoans, charophytes Helium porosity (percent): Common pore types include skeletal moldic porosity, intergrain porosity, pelmoldic porosity, root-mold porosity, and intraparticle. Mean porosity is 27.1, n = 85, range from 10.8 to 48.3 Air permeability (millidarcies): Mean maximum horizontal is 3,279, n = 84, range from 0.2 to 19,318; mean vertical is 3,102, n = 83, range from 0 to 20,140 Paleoenvironment: Mainly restricted platform interior, minor open-marine platform interior and platform margin-to-outer platform
Color: Very pale orange 10YR 8/2, grayish orange 10YR 7/4, dark yellowish orange 10YR 6/6, moderate yellowish brown 10YR 5/4, pale yellowish brown 10YR 6/2 Depositional texture: Coral framestone Sedimentary structures/textures: Massive with borings and vugs Carbonate and accessory grains: Mainly Monastrea head coral, minor medium to large pebble-sized Schizoporella; trace to 5 per- Coral framestone cent quartz grains with peloids in boring and vug fill Helium porosity (percent): Common pore types include intragrain porosity, separate-vug porosity, and root-mold porosity. Mean porosity is NDA Air permeability (millidarcies): Mean maximum horizontal is NDA and mean vertical is NDA Paleoenvironment: Platform margin-to-outer platform
Color: Very pale orange 10YR 8/2, very light gray N8 Depositional texture: Pelecypod floatstone and rudstone with skeletal wackestone, packstone or grainstone matrix Sedimentary structures/textures: Thickly to very thickly bedded Carbonate and accessory grains: Mainly mollusks (Chione, Turritella, Trachycardium, Bellucina, Cerithium, Diodora, Muricid, Brachidontes, Modulus, Anomalocardia?, Divaricella, Bulla, pectenids, arcids, Glycymeris, muricids, ostreids, Phacoides, Vermicularia, Anodontia, Codakia, Conus, Lithopoma, Oliva, Turbo, Anadara, Carolinapecten, Nuculana, Parastarte) benthic Pelecypod floatstone foraminifers (including archaiasinids, peneroplids, miliolids, Parasorites, soritids, Ammonia, Elphidium, Androsina, rotaliforms, and rudstone Gypsina?, Nonion?, amphistiginids, agglutinating foraminifera, Bolivina, Cyclorbiculina, Cycloputeolina), peloids, ostracods; minor quartz grains; trace echinoids, red algae, charophytes, globigerinids Helium porosity (percent): Common pore types include moldic intergrain, irregular separate and touching vugs. Mean porosity is 26.8, n = 89, range from 10.0 to 50.2 Air permeability (millidarcies): Mean maximum horizontal is 6,922, n = 90, range from 0.3 to 27,411; mean vertical is 3,485, n = 90, range is 0 to 18,551 Paleoenvironment: Mainly restricted to open platform interior, minor platform margin-to-outer platform Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer
Table 4. Summary of lithofacies of the Miami Limestone, Fort Thompson Formation, and selected lithofacies of the Tamiami Formation in north-central Miami-Dade County. (Continued)
Lithofacies Description
Color: Very pale orange 10YR 8/2, very light gray N8 Depositional texture: Pelecypod floatstone and rudstone with peloid and skeletal fragment wackestone and packstone matrix Sedimentary structures/textures: Medium to very thickly bedded Carbonate and accessory grains: Mainly peloids, mollusks (including Chione, Modulus, Turritella, Codakia, Lucina, Cerithium, Trachycardium, Lucinisca, Pecten, Diplodonta, Strombus, Pleuromeris, Carditimera, Anadara, Glycymeris, Anodonita, Cardium, Touching-vug Dosinia, Nucula, Turbo, Glycymeris, Pecten?, Astralium, Nuculana, Phacoides, Divaricella), skeletal fragments, benthic fora- pelecypod floatstone minifers (including soritids, archaiasinids, miliolids, Ammonia, Parasorites, amphistiginids, Elphidium, peneroplids, rotaliforms, and rudstone Androsina), ostracods, echinoids; trace Porites coral, red algae, bryozoans Helium porosity (percent): Common pore types include skeletal moldic porosity, 5 to 100 percent separate and touching vugs. Mean porosity is 36.4, n = 5, range from 32.0 to 42.1. Air permeability (millidarcies): Mean maximum horizontal is 8,358, n = 4, range from 2,731 to 16,478; mean vertical is 7,881, n = 7, range from 1,387 to 16,468 Paleoenvironment: Open-marine platform interior
Color: Very pale orange 10YR 8/2 Depositional texture: Peloid wackestone and packstone Sedimentary structures/textures: Thickly to very thickly bedded Carbonate and accessory grains: Mainly peloids, benthic foraminifers (including miliolids), gastropods; minor to abundant quartz Vuggy wackestone grains and packstone Helium porosity (percent): Common pore types include irregular separate and touching vugs. Mean porosity is 27.0, n = 3, range from 24.9 to 30.8 Air permeability (millidarcies): Mean maximum horizontal is 8,358, n = 4, range from 2,731 to 16,478; mean vertical is 9,403, n = 3, range from 5,524 to 12,981 Paleoenvironment: Restricted platform interior (includes mud banks)
Color: Very pale orange 10YR 8/2, very light gray N8 Depositional texture: Skeletal sandstone Sedimentary structures/textures: Thickly to very thickly bedded Quartz sandstone Carbonate and accessory grains: Mainly quartz sand, peloids, pelecypods, skeletal fragments, gastropods, echinoids; foraminifera can include globigerinids, amphistiginids, Ammonia, Elphidium, miliolids and skeletal quartz sandstone* Helium porosity (percent): Common pore types include interparticle and skeletal mold porosity. Mean porosity is 14.0, n = 5, range from 8.3 to 19.7 Air permeability (millidarcies): Mean maximum horizontal is 609, n = 4, range from 0.67to 1,736; mean vertical is 1,088, n = 5, range from 0 to 3,333 Paleoenvironment: Mainly middle ramp of the Tamiami Formation
Color: Very pale orange 10YR 8/2, very light gray N8 Depositional texture: Quartz sand Sedimentary structures/textures: Thickly to very thickly bedded Carbonate and accessory grains: Mainly quartz sand, peloids, pelecypods, skeletal fragments, gastropods; foraminifera include Quartz sand* globigerinids and amphistiginids Helium porosity (percent): Common pore types include interparticle and skeletal mold porosity. Mean porosity is NDA Air permeability (millidarcies): Mean maximum horizontal is NDA and mean vertical is NDA Paleoenvironment: Mainly middle ramp of the Tamiami Formation 30 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
MAJOR PORE CLASSES & CYCLOSTRATIGRAPHY EPOCH DEPOSITIONAL GROUND-WATER LITHOFACIES IDEAL QU FM HU HFC HFCS ENVIRONMENTS FLOW TYPE CYCLES Holocene Freshwater Low permeability Peat, muck, marl - - - -- HFCB FS Peloid e Conduit packstone/ Q5 OMPI grainstone HFC5e HFCB FS Leaky, low Peloid wackestone/
Q4 packstone Aggradational
HFC4 permeability Miami Limeston FW PFlt/Rud HFCB FS Leaky, low Brackish Mudstone/wackestone permeability Leaky, low Freshwater PFlt/Rud HFC3b permeability Tidal flat Conduit HFCB FS HFC3a Skeletal Pks/Grn stromatolite marker Q3 Diffuse OMPI Pelecypod Flt/Rud
HFC3a
Conduit Touching-vug pelecypod Flt/Rud
Freshwater Leaky, low permeability PFlt/Rud Brackish Skeletal Pks/Grn HFCB FS Restricted Diffuse Trace Planorbella
Sandy pelecypod Flt/Rud HFC2h OMPI HFCB FS Restricted Diffuse Pelecypod Flt/Rud
OMPI HFC2g3 Freshwater Leaky, low permeability PFlt/Rud HFCB FS Restricted Sandy skeletal Pks/Grn
Q2
Pleistocene Diffuse OMPI Pelecypod Flt/Rud HFC2g2
HFCB FS Biscayne aquifer Freshwater Leaky, low permeability PFlt/Rud Diffuse Sandy pelecypod Flt/Rud OMPI HFC2g1
Progradational Freshwater Leaky, low permeability PFlt/Rud HFCB FS Restricted Diffuse Sandy pelecypod Flt/Rud
Fort Thompson Formation OMPI Conduit Sandy touching-vug pelecypod HFC2e2 Flt/Rud HFCB FS Restricted Diffuse Sandy skeletal Pks/Grn
OMPI HFC2d Conduit Sandy pelecypod Flt/Rud Brackish Leaky, low permeability PFlt/Rud HFCB FS ? Sandy skeletal Pks/Grn Restricted and Conduit OMPI Sandy pelecypod Flt/Rud
Diffuse Sandy skeletal Pks/Grn HFC2c OMPI Conduit Sandy pelecypod Flt/Rud HFCB FS Brackish Leaky, low permeability Mudstone/wackestone Q1? Restricted Conduit Sandy pelecypod Flt/Rud OMPI HFC2b Leaky, low permeability Pedogenic limestone HFCB FS Outer Coral framestone platform Diffuse Sandy skeletal Pks/Grn to platform HFC2a Conduit Sandy pelecypod Flt/Rud margin ? HFCB? FS? EXPLANATION LITHOFACIES LOW-PERMEABILITY PEAT, MUCK, AND MARL FM FORMATION Flt/Rud FLOATSTONE/RUDSTONE FS FLOODING SURFACE PFlt/Rud PLANORBELLA FLOATSTONE/RUDSTONE PORE-CLASS III PORE FW FRESHWATER Pks/Grn PACKSTONE/GRAINSTONE HFC HIGH-FREQUENCY CYCLE CLASSES PORE-CLASS II HFCB HIGH-FREQUENCY CYCLE PORE CLASS I BOUNDARY HFCS HIGH-FREQUENCY CYCLE SET AGGRADATIONAL SUBTIDAL CYCLE HU HYDROGEOLOGIC UNIT IDEAL UPWARD-SHALLOWING PARALIC CYCLE OMPI OPEN-MARINE PLATFORM INTERIOR CYCLES QU Q-UNIT (Perkins, 1977) UPWARD-SHALLOWING SUBTIDAL CYCLE CALCRETE SUBAERIAL EXPOSURE SURFACE - UNDEFINED PARAMETER
Figure 8. Conceptual hydrogeologic column for the northern part of the study area that includes ages, major depositional environments, ground-water flow types, pore classes, lithofacies, cyclostratigraphy, Q-units of Perkins (1977), formations, and hydrogeologic units. Planorbella mold Vug Core-plug hole Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer
Freshwater ponds Brackish Restricted platform Platform margin-to- and marshes platform interior interior Open-marine platform interior outer platform
Mud- mound? barrier Mean sea level (NGVD 29) ?
Fort Thompson Formation
Middle-ramp Tamiami Formation EXPLANATION LITHOFACIES FOSSILS PORE CLASS Planorbella floatstone and rudstone Planorbella Pore Class III Ammonia Mudstone and wackestone Pore Class II Sediment-filled Miliolids semivertical Skeletal packstone and grainstone Skeletal fragments Pore Class I Pelecypods root mold(?) Touching-vug pelecypod floatstone and rudstone Soritids, archaiasinids, peneroplids Coral framestone Amphistiginids Sandy pelecypod floatstone and rudstone Corals
Conglomerate Unconformity
Figure 9. Conceptual facies model showing relations between major lithofacies, depositional environments, and pore classes for the study area. The four photographs of characteristic slabbed-core samples from the Fort Thompson Formation illustrate some of the carbonate textures and diagenetic features associated with key lithofacies. Each incremental color change represents 1 cm (0.394 in.) on the scale bars. 1 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Middle Ramp Formation underlying the four lithofacies representative of the platform margin-to-outer platform environment include: A middle ramp is characteristic of parts of the Pinecrest (1) quartz sands, (2) shallowing‑upward limestone cycles of Sand Member of the Tamiami Formation. Lithofacies common the Tamiami Formation, and (3) pelecypod floatstone and to the middle ramp or Pinecrest Sand Member of the Tamiami rudstone. Uncommon calcrete separating the Fort Thompson Formation in the study area include pelecypod floatstone Formation from the Tamiami Formation suggests that an and rudstone, quartz sandstone and skeletal quartz sand- irregular subaerial unconformity separates the two formations. stone, quartz sand, and unconsolidated pelecypod rudstone. Mollusks, amphistiginids, and globigerinids are common to these rocks of the Pinecrest Member of the Tamiami Open-Marine Platform Interior Formation. Less common, but present in a few samples Overlying the platform margin-to-outer platform deposi- representative of this depositional environment, are echinoids, tional facies in the lowermost Fort Thompson Formation are miliolids, rotaliform foraminifera, soritids, and peneroplids. open-marine platform interior depositional facies, suggesting The amphistiginid and globigerinid foraminifera are indicative upward shallowing and platform progradation within the of deposition in relatively deep marine water. Rose and Lidz lower Fort Thompson Formation (figs. 8 and 9). For the Fort (1977) found these foraminiferal groups to be important on the Thompson Formation, lithofacies characteristic of the open- upper slope of the Florida and Bahama Platforms, where they marine platform interior depositional environment include reported approximate water depths ranging from 131 to 656 ft. touching‑vug pelecypod floatstone and rudstone, sandy The shallow depth of this 131- to 656-ft range, however, is touching‑vug pelecypod floatstone and rudstone, skeletal most probable because the uncommon foraminiferal occur- packstone and grainstone, and sandy skeletal packstone and rence of soritids and peneroplids is consistent with deposition grainstone lithofacies. Common to these lithofacies are benthic in an open-marine platform interior, where water depths are foraminifers (soritids, archaiasinids, and peneroplids) that are reported to range from about 0 to 98 ft by Rose and Lidz consistent with deposition in an open-marine platform interior, (1977) on the Florida and Bahama Platforms. The limestone similar to the modern platform interior of southern Florida assigned to a middle ramp environment is commonly that is seaward of the present-day islands of the Florida Keys pelecypod rudstone with a well-washed, grain-dominated (Rose and Lidz, 1977; Lidz and Rose, 1989). These lithofacies matrix (Lucia, 1995) and lime mud-rich pelecypod floatstone. are commonly highly burrowed. The association of a soritid-, The mixture of these grain-dominated and mud-dominated archaiasinid-, and peneroplid-dominated foraminiferal assem- carbonates and a lack of shallow-water indicators or exposure blage and preservation of a highly burrowed lithofacies is sug- suggest deposition below fair-weather wave base (FWWB) but gestive of deposition below FWWB in a lower shoreface zone. above storm wave base (SWB). This zone between FWWB Mollusks present in samples from the pelecypod-rich lithofa- and SWB defines the “mid-ramp” depositional environment cies are suggestive of the outer estuary to shallow-marine (Burchette and Wright, 1992). platform interior environments of Florida Bay (app. III). Two lithofacies, peloid wackestone and packstone and Platform Margin-to-Outer Platform peloid packstone and grainstone, characterize the Miami Limestone (fig. 8). Burrowing of these lithofacies is pervasive The four lithofacies from limestone of the Fort Thompson and resembles many of the types of burrows described by Formation that distinguish the platform margin-to-outer Shinn (1968), Halley and Evans (1983), and Evans (1984). platform environments include coral (Montastrea) framestone, A benthic foraminiferal assemblage dominated by archaia- conglomerate, sandy skeletal packstone and grainstone, sinids, soritids, and peneroplids in the peloid wackestone and sandy pelecypod floatstone and rudstone lithofacies. and packstone lithofacies is consistent with deposition in an The grainy lithofacies contain amphistiginids, which prefer open-marine platform interior (Rose and Lidz, 1977; Lidz and areas of reef growth at the platform margin of the modern Rose, 1989). Alternatively, the archaiasinid, soritid, and pen- southern Florida platform, and patch reefs and nearby environ- eroplid assemblage could be suggestive of shallow, somewhat ments not far (possibly about 2 mi) from the platform margin restricted, possibly even somewhat hypersaline or euryhaline (Rose and Lidz, 1977). Rose and Lidz (1977) estimated conditions (Hallock and Glenn, 1986). Schizoporella bryozoan that water depths of the platform margin-to-outer platform is commonly present in both lithofacies. The two lithofacies environments range from 0 to 131 ft. The Montonastrea correspond to the bryozoan facies of Hoffmeister and others equivocally have a flat morphology, suggesting growth (1967), which they interpreted to represent an open-marine in water depths of about 82 ft or greater (Pamela Hallock shelf lagoon. Later, both Perkins (1977) and Evans (1984) Muller, University of South Florida, oral commun., 2005). indicated deposition of the bryozoan facies was on an open- The platform margin-to-outer platform environments are a marine platform. Presence of an open-marine platform interior notable exception because they are present only at the base foraminiferal assemblage and preservation of abundant bur- of the Fort Thompson Formation in the study area. Rocks or rowing suggest deposition below FWWB in a lower shoreface sediments of the uppermost Pinecrest Member of the Tamiami zone. Multidisciplinary Approach—Characterizing the Geologic Framework of the Biscayne Aquifer
Restricted Platform Interior, Brackish Platform Interior, Cunningham and others, 2004b; 2004c). It is beyond the scope and Freshwater Terrestrial of the present study to determine whether the HFCs in the Biscayne aquifer have a eustatic (for example, Perkins, 1977; Characteristic of the restricted platform interior environ- Multer and others, 2002) or autocyclic origin because this ment is mainly highly burrowed, pelecypod floatstone and study includes only part of the lateral extent of the uppermost rudstone, sandy pelecypod floatstone and rudstone, skeletal Tamiami Formation, Fort Thompson Formation, and Miami packstone and grainstone, and sandy skeletal packstone and Limestone. grainstone lithofacies. Miliolids commonly dominate the benthic foraminiferal assemblage of the lithofacies, which is Delineation of Cycles and Ideal Cycles consistent with deposition in a restricted platform interior. Rose and Lidz (1977) and Lidz and Rose (1989) noted that miliolid- The HFCs form the fundamental building blocks of the dominated benthic foraminiferal assemblages are common in rocks that constitute the Biscayne aquifer (fig. 4). The fitting restricted areas of modern Florida Bay. The combined associa- of vertical lithofacies successions between substantial tion of a miliolid-dominated foraminiferal assemblage and bounding surfaces (flooding surfaces) define these cycles. preservation of a highly burrowed lithofacies suggests deposi- In some cases, a calcrete layer indicative of subaerial exposure tion below FWWB in a lower shoreface zone. delineates the flooding surface (fig. 8). A flooding surface is The mudstone and wackestone lithofacies commonly a boundary that separates younger from older strata, across distinguishes the brackish platform interior environment. This which there is a sharp upward increase in paleowater depth lithofacies is principally micrite and has an abundance of the (Van Wagoner and others, 1988). Flooding surfaces herein benthic foraminifer Ammonia and smooth-shelled ostracodes. indicate a sharp upward deepening of paleomarine water depth Charophytes, the benthic foraminifer Elphidium, and the or paleoflooding of a subaerial exposure surface by seawater freshwater gastropod Planorbella are less commonly present. or freshwater. Other types of benthic foraminifers are not common. Modern Three distinct recurring vertical assemblages of lithofa- Florida Bay sediments with large populations of Ammonia cies translate into three ideal HFCs: an upward-shallowing and Elphidium and containing few other foraminiferal spe- subtidal cycle, an upward-shallowing paralic cycle, and an cies are indicative of a brackish platform interior (Rose and aggradational subtidal cycle (fig. 10 and table 5). Paralic envi- Lidz, 1977; Lidz and Rose, 1989). Ishman and others (1997) ronmental facies cap the upward-shallowing paralic cycles. and Brewster-Wingard and others (1997) found Ammonia- The principal characteristic of paralic depositional environ- Elphidium assemblages to be present in hyposaline-influenced ments is that they occur at the transition between marine and areas of modern Biscayne Bay and Florida Bay, respectively. terrestrial realms—estuaries, coastal lagoons, marshes, and The Planorbella floatstone and rudstone lithofacies char- coastal zones subject to high freshwater input (Debenay and acterizes a freshwater terrestrial environment. This micrite- others, 2000). The vertical stacking of lithofacies and associ- rich lithofacies commonly contains abundant Planorbella, ated interpretive depositional environments within the ideal smooth-shelled ostracodes, and charophytes. Interpretation HFCs are shown in figure 10. The two upward-shallowing indicates deposition of the Planorbella-rich beds in freshwater ideal cycles are present only within the Fort Thompson ponds or marshes (Galli, 1991). Formation and the aggradational subtidal cycle is present only within the Miami Limestone. Cyclostratigraphy Cycle Hierarchy The cyclostratigraphy presented herein divides funda- mental depositional cycles, high-frequency cycles (HFCs), In the Fort Thompson Formation and Miami Limestone, into units defined by distinct vertical lithofacies successions two hierarchical levels of cyclicity are recognized. The HFCs bounded by surfaces across which there is evidence for a are the fundamental cycle type, but based on upward trends relative increase in sea level (Kerans and Tinker, 1997). of progradation or aggradation, they group into two HFC Relative changes in sea level can have substantial control sets (fig. 8 and table 6). The lower HFC set (Fort Thompson over the vertical stacking patterns of lithofacies on carbonate Formation) displays a broad uniform upward-shallowing trend platforms (Kerans and Tinker, 1997). Although the concept indicative of carbonate shelf progradation based on a cycle- of sea-level control on cycle production has been challenged scale seaward progression of lithofacies tracts, shifting upward (Drummond and Wilkinson, 1993; Miall, 1997), the system- from deeper depositional environments to those that are shal- atic application of cyclostratigraphy has been shown to be lower within the study area. The singular vertical lithofacies an effective approach for defining spatial relations between characteristics and general lack of any lateral or vertical shift stratigraphic and aquifer properties, especially porosity and in lithofacies tracts within the two HFCs of the upper HFC set permeability (Hovorka and others, 1996; 1998; Lucia, 1999; (Miami Limestone) are suggestive of carbonate shelf aggrada- Budd, 2001; Ward and others, 2003; Budd and Vacher, 2004; tion (Kerans and Tinker, 1997) in the study area. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Upward-Shallowing Subtidal Cycle Upward-Shallowing Paralic Cycle (Fort Thompson Formation) (Fort Thompson Formation) Ground- Ground- Major Depositional Pore Major Depositional Pore water water lithofacies environment class lithofacies environment class flow type flow type Skeletal Planorbella floatstone Freshwater Leaky, packstone and and rudstone and/or and/or III grainstone, mudstone and brackish platform low sandy skeletal Restricted wackestone interior permeability platform packstone and Skeletal grainstone, interior to Diffuse packstone and open- II pelecypod carbonate grainstone, Restricted marine floatstone flow sandy skeletal platform platform packstone and and rudstone, interior to sandy pelecypod interior grainstone, Diffuse open- II floatstone and pelecypod carbonate marine rudstone floatstone flow and rudstone, platform Touching-vug sandy pelecypod interior pelecypod floatstone and
Upward shallowing floatstone and Upward shallowing rudstone Open- rudstone, Touching-vug marine pelecypod sandy I Conduit platform floatstone and Open- touching-vug flow marine interior rudstone, sandy I Conduit pelecypod touching-vug platform flow floatstone and pelecypod interior rudstone floatstone and rudstone
Two Aggradational Subtidal Cycles EXPLANATION (Miami Limestone) MICRITE-DOMINATED MATRIX LAMINATED CALCRETE Ground- Major Pore Depositional water GRAIN-RICH OR GRAIN- lithofacies environment class FLOODING SURFACE flow type DOMINATED MATRIX IRREGULAR VUGS MOLDICAND IRREGULAR VUGS THIN ROOT MOLDS VERTICALVUGS Peloid packstone I Conduit and flow grainstone Open- marine
Aggradational platform interior
Peloid Leaky, wackestone III low Figure 10. Idealized fifth-order cycles (table 5) for the Fort and permeability packstone Thompson Formation and Miami Limestone showing relations Aggradational between lithofacies, depositional environments, porosity (pore classes), and ground-water flow types.
Table 5. Ideal cycles of the Fort Thompson Formation and Miami Limestone.
Cycle type Major depositional environments Description
Cycle thickness ranges from 0.1 to 13.0 feet; mean is 4.2 feet. Little or no change. in Aggradational grain size upward through succession. Mainly peloid packstone and grainstone or peloid Open-marine platform interior subtidal wackestone and packstone lithofacies. Top of upper boundary is an exposure surface (calcrete)
Cycle thickness ranges from 1.0 to 13.8 feet; mean is 5.6 feet. Fining upward succes- Open-marine platform interior sion. Base typically burrowed peleypod-rich floatstone or rudstone lithofacies, which Upward-shallowing Restricted platform interior may be quartz sand rich, grading upward to mudstone and wackestone or Planorbella paralic Brackish platform interior floatstone and rudstone cap. Commonly, upper boundary is an exposure surface (cal- crete). Planorbella present in capping Planorbella floatstone and rudstone lithofacies, Freshwater terrestrial and local occurrence in mudstone and wackestone lithofacies
Cycle thickness ranges from 0.3 to 13.2 feet; mean is 5.2 feet. Mostly fining upward Upward-shallowing Open-marine platform interior succession. Base typically burrowed peleypod-rich floatstone or rudstone, which may be subtidal Restricted platform interior quartz sand rich, grading upward to packstone and grainstone. Upper boundary may be an exposure surface (calcrete) Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
Table 6. Terminology of stratigraphic cycle hierarchies and Hydrogeologic Framework for Model orders of cyclicity. [Modified from Kerans and Tinker (1997). >, greater than the value] Representation of the Biscayne Aquifer
Hierarchical Sequence Duration Geologic units of varying permeability that underlie order stratigraphic unit (million years) southeastern Florida to depths between about 180 and 220 ft below NGVD 1929 are known as the surficial aquifer system, First None >100 an unconfined aquifer system that is the source of much of Second Supersequence 10–100 the potable water used in the study area (Fish, 1988; Fish and Stewart, 1991). In Miami-Dade County, the upper, highly Third Depositional sequence 1–10 permeable part of the aquifer system is named the Biscayne Composite sequence aquifer (Parker, 1951; Parker and others, 1955). Underlying Fourth High-frequency sequence 0.1–1 the Biscayne aquifer are two semiconfining units that occur High-frequency cycle set above and below the gray limestone aquifer (Reese and Fifth High-frequency cycle 0.01–0.1 Cunningham, 2000; fig. 3, this report). The geology and hydrology of the study area have been reported in numerous Sixth Microcycle <0.01 studies (Parker and Cooke, 1944; Parker and others, 1955; Perkins, 1977; Causaras, 1987; Labowski, 1988; Fish and Orders of Cycles Stewart, 1991; Galli, 1991; Solo-Gabriele and Sternberg, 1998; Nemeth and others, 2000; Sonenshein, 2001; Within the study area, a hierarchical order is proposed Cunningham and others, 2004b; 2004c; Wilcox and others, herein for the cyclicity recognized in the Fort Thompson 2004; Cunningham and others, 2006, in press). Formation and Miami Limestone; HFCs are fifth-order scale or higher and HFC sets are fourth-order scale (table 6). Previous Interpretations The proposed scales for the cycle ordering are based on various ranges in ages proposed by Multer and others In Miami-Dade County, the surficial aquifer system (2002) and Hickey (2004) for the five unconformity-bound includes all rock and sediment from land surface downward Quaternary marine units or Q units defined by Perkins to the top of the intermediate confining unit (fig. 3). The rock (1977). The Q1 to Q5 units of Perkins (1977) correlate to and sediment are mostly composed of limestone, sandstone, the new cyclostratigraphy (present study) shown in figures sand, shell, and clayey sand and range in age from Holocene 4 and 8, based on comparisons of descriptions of lithofacies to Pliocene (Causaras, 1987). The top of the system is land and unconformities by Perkins (1977) to those observed in surface, and a substantial decrease in permeability defines the present study. No lithofacies or unconformity observed the base. The permeability of the rock and sediment of the in the study area reliably correlate to the Q1 unit of Perkins surficial aquifer system is variable, allowing the system to be (1977) shown in figure 4. Multer and others (2002) assumed divided into one or more aquifers separated by less-permeable a maximum age of 420 ka for the Q1 unit of Perkins (1977) or semiconfining units. The uppermost part of these water- in the basal Fort Thompson Formation (fig. 4) and reported bearing units is the Biscayne aquifer, and the lowermost water- that the Q5 unit of Perkins (1977) accumulated during the bearing unit is the gray limestone aquifer (Fish and Stewart, Marine Isotope Substage 5e, which terminated at about 114 ka 1991; Reese and Cunningham, 2000). (Shackleton and others, 2003). One model of the ordering of The Biscayne aquifer is the primary aquifer in south- cyclicity, thus, assumes a maximum duration of about 306 ky eastern Florida and has been declared a sole-source aquifer for accumulation of the 13 HFCs identified in the study area, (Federal Register Notice, 1979). Parker (1951) named or average cycle duration of about 23.5 ky, which is consistent and defined the Biscayne aquifer as a hydrologic unit of with fifth-order cyclicity (table 6). Fourth-order scaling of water-bearing rocks that carries unconfined ground water in the HFC sets is in agreement with cycle-set durations based southeastern Florida. Later, Fish (1988), defined the Biscayne on Q‑unit ages presented in Perkins (1977) and Multer and aquifer more completely as: others (2002). Alternatively, a second model of the ordering of That part of the surficial aquifer system in cyclicity suggests that the HFCs are fifth-order or higher. This southeastern Florida composed of (from land surface model assumes a short-duration pulsed flooding of the Florida downward) the Pamlico Sand, Miami Oolite [Lime- platform during the Pleistocene, as suggested by correlation of stone], Anastasia Formation, Key Largo Limestone, the Perkin’s Q units to various marine isotope stages (Hickey, and Fort Thompson Formation (all of Pleistocene 2004). The HFCs bundled within the Q1?, Q2, and Q3 units age) and contiguous, highly permeable beds of the of Perkins (1977) are possibly microcycles (Zühlke, 2004) Tamiami Formation of Pliocene and late Miocene with duration less than 10 ky. The single HFCs defined within age where at least 10 ft of section is very highly the Q4 and Q5 units of Perkins (1977) could be composed of permeable (a horizontal hydraulic conductivity of fifth-order cycles (table 6). about 1,000 ft/d or more). A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Fish (1988) provided further definition of the base of the and the aggradational subtidal cycles of the Miami Limestone Biscayne aquifer: (Cunningham and others, 2004b; 2006, in press). The 16 litho- facies of the Fort Thompson Formation and Miami Limestone If there are contiguous, highly permeable (having (previously described) have been assigned to pore classes I, II, hydraulic conductivities of about 100 ft/d or more) or III (figs. 11 and 12), as presented in table 7. These lithofa- limestone or calcareous sandstone beds of the cies have rather unique stratigraphic spatial distributions, and Tamiami Formation, the lower boundary is the tran- sition from these beds to subjacent sands or clayey distinct porosity, permeability, and storage characteristics. sands. Where the contiguous beds of the Tamiami Table 7 also describes how the three pore classes relate to Formation do not have sufficiently high perme- three ground-water flow types defined by Cunningham and ability, the base of highly permeable limestones others (2004b). or sandstones in the Fort Thompson Formation, Pore class I commonly comprises the lower part of many Anastasia Formation, or Key Largo Limestone is the upward-shallowing cycles of the Fort Thompson Formation base of the Biscayne aquifer. and the upper aggradational subtidal cycle of the Miami Limestone where porosity and permeability are highest (figs. 8 This study focuses on the part of the Biscayne aquifer and 10). Characteristic lithofacies associated with pore class I that is composed of the uppermost part of the Tamiami are: (1) touching‑vug pelecypod floatstone and rudstone, Formation, the Fort Thompson Formation, and the Miami (2) peloid packstone and grainstone, (3) laminated peloid Limestone (fig. 3). The key wells used in this study fully packstone and grainstone, (4) autobreccia, (5) coral frame- penetrate the rocks of the Biscayne aquifer. Cunningham and stone, and (6) vuggy wackestone and packstone (table 7). Pore others (2004b) concentrated on the uppermost part of the types that can be associated with specific lithofacies include Biscayne aquifer. solution-enlarged fossil molds up to pebble size, molds of burrows or roots, irregular vugs surrounding casts of burrows Pore System of the Limestone of the or roots, bedding‑plane vugs, and irregular vugs or cavities Biscayne Aquifer of uncertain textural association up to about 4 ft in height (figs. 11 and 12). Touching‑vugs are the most common type Traditionally, karst aquifers are characterized by three of interconnected (effective) porosity in this class. A tabular, types of porosity: interparticle matrix porosity, fracture three-dimensional, stratiform geometry regionally character- porosity, and large cavernous porosity (Martin and Screaton, izes the touching‑vug flow zones, which are constrained 2001). This has led many researchers to view karst aquifers between cycle boundaries, based on correlations of porous as two component systems, where much of the ground-water zones in the study area (pls. 1-5). An important point is that storage occurs in the matrix porosity or fractures or both, and the touching vugs of the two upward-shallowing cycle types of much of the ground-water flow and transport takes place in the Fort Thompson Formation are typically most concentrated the large dissolutional conduits (Martin and Screaton, 2001). just above the flooding surface in the lower part of the cycles, In the young eogenetic karst that defines the Pleistocene and the upper aggradational cycle of the Miami Limestone limestone of the Biscayne aquifer, however, a fourth porosity has a generally regular vertical distribution of touching vugs type, touching‑vug porosity, is especially important in terms throughout the cycle. Therefore, accurate cycle correlation of conveyance of ground water (Vacher and Mylroie, 2002; can produce a realistic linkage of permeable or preferential Cunningham and others, 2006, in press). The triple porosity ground-water flow zones. Typical ground-water flow in pore of the Biscayne aquifer is typically: (1) matrix of interparticle class I should not be conceptually viewed as movement of and separate-vug porosity, providing much of the storage; ground water through a system of pipes or underground (2) touching‑vug porosity creating stratiform ground-water stream conduits, but more of a stratiform passage formed flow passageways; and (3) less common, conduit porosity by coalescence of touching vugs into a mostly tortuous path composed mainly of bedding‑plane vugs, thin solution pipes, for the movement of conduit ground-water flow. Figure 13 and cavernous vugs (figs. 11 and 12)―these three conduit exemplifies the stratiform distribution of pore class I locally porosity types are all pathways for conduit ground-water flow. Stratiform refers to the three-dimensional aspects of the within the NWWF (fig. 2), notably where the darkened area porosity; that is, it is constrained to a layer, bed, or stratum at the base of HFC2e2 in digital optical borehole images with lateral continuity (Jackson, 1997). represents touching‑vug porosity. Figure 14 shows how both molds of borrows and interburrow porosity in well G‑3816 combine to create a stratiform zone of effective porosity at the Pore Classes base of HFC2e2 (fig. 13). Cunningham and others (2004b) In the study area, the porosity, permeability, and storage showed that pore class I has the highest porosity and perme- of the limestone in the Biscayne aquifer relate directly to litho- ability of the three pore classes defined herein; however, the facies and have a predictable vertical distribution within the terminology they used for pore class I was “horizontal conduit upward-shallowing cycles of the Fort Thompson Formation ground-water flow class.” Touching-Vug Porosity Conduit Porosity Thin Solution Pipes G-3792 G-3770 A G-3792 B C 48 50 Photo of quarry sample
ACE
ACE
, BELOW 22 5 INCHES
ACE
, BELOW
LAND SURF
DEPTH IN FEET
LAND SURF 55 51
BELOW LAND SURF
DEPTH IN FEET Intra-burrow porosity , Leaky, low-permeability Thin solution pipes in Hydrogeologic Framework for Model Representation of the Biscayne Aquifer 23 IN FEET zone very low porosity matrix Fossil-moldic porosity Fossil mold Matrix Diagram of quarry sample
Tortuous ground-water flow DEPTH Very low porosity matrix Miami 60 Limestone Cavernous vugs 5 INCHES Vug-to-vug flow Fort Thompson Formation Example of conduit flow through touching vugs G-3717 G-3795 Example of conduit flow 45 through bedding-plane vugs 21.8 G-3794 Leaky, Thin solution pipes 15 low-permeability
ACE Vug , BELOW zone
ACE
, BELOW 46
ACE Example 21.9 , BELOW of conduit LAND SURF flow through
DEPTH IN FEET LAND SURF 47 vertical LAND SURF solution DEPTH IN FEET 22.0 Inter-root-cast porosity
DEPTH IN FEET pipes 20 Irregular vugs Bedding-plane vugs Pore Class I Pore Class III
Figure 11. Relation between pore classes I and III and touching-vug and conduit pore types, respectively, for the Fort Thompson Formation and Miami Limestone of the Biscayne aquifer in the study area. (A) Four common types of touching-vug porosity: fossil moldic, intra-burrow, irregular vugs, and inter-root-cast porosity
for pore class I; (B) Two types of conduit porosity (cavernous and bedding-plane vugs) that are rather untypical for pore class I; (C) Thin, vertical conduits that are a typical pore type of pore class III. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Matrix Porosity
Fossil-moldic Ground-water porosity flow
Figure 12. Relation between pore class II and matrix porosity. Ground-water flow through the matrix is general matrix-to- vug-matrix flow. Core Matrix-to-vug-to-matrix flow sample of pelecypod floatstone and rudstone Interparticle lithofacies shown in porosity 0 1 INCH Particles photo on left-hand side is from the Fort Thompson Formation Pore Class II in the G-3783 test corehole (fig. 2).
Table 7. Pore classes (I, II, and III) related to aquifer attributes of the Miami Limestone and Fort Thompson Formation in the study area.
[mD, millidarcies; HFC, high-frequency cycle; n, number of samples used to calculate median]
Major type ground- Pore Median whole-core Median maximum horizon- water flow type Lithofacies Major pore type class helium porosity tal air permeability and relative permeability
Touching vugs includ- Touching-vug pelecypod HFC5e aggradational HFC5e aggradational ing fossil-moldic, floatstone-rudstone, peloid subtidal cycle of Miami subtidal cycle of Miami intra-burrow, and packstone-grainstone, Limestone and lower part Limestone and lower part inter-root-cast porosity, Conduit flow, high laminated peloid packstone- of upward shallowing of upward shallowing I and irregular vugs; and permeability grainstone, autobreccia, cycles of Fort Thompson cycles of Fort Thompson conduit porosity includ- coral framestone, and vuggy Formation is 33.4 percent; Formation is 8,498 mD; ing bedding-plane-vugs wackestone and packstone n = 54 n = 52 and cavernous vugs
Middle part of upward- Middle part of upward- Skeletal packstone-grain- shallowing paralic cycles shallowing paralic cycles stone, pelecypod floatstone- Matrix porosity includ- and middle to upper part and middle to upper part Diffuse-carbonate flow, II rudstone, quartz sandstone ing interparticle and of upward-shallowing of upward-shallowing moderate permeability and skeletal quartz sandstone, separate vugs subtidal cycles is 25.0 subtidal cycles is 2,784 and quartz sand percent; n = 110 mD; n = 113
HFC4 aggradational HFC4 aggradational subtidal cycle of Miami subtidal cycle of Miami Mudstone-wackestone, Pla- Limestone and commonly Limestone and commonly norbella floatstone-rudstone, Separate vugs including cycle top of upward-shal- cycle top of upward-shal- peloid wackestone-packstone, moldic porosity or thin III lowing paralic cycles of lowing paralic cycles of Leaky, low permeability conglomerate, pedogenic vertical solution pipes Fort Thompson Forma- Fort Thompson Formation limestone, and gastropod or both tion (an exception is (an exception is base of floastsone-rudstone base of HFC3a) is 17.6 HFC3a) is 575 mD; percent;n = 78 n = 74 Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
A A´ West S-3163 DISTANCE BETWEEN WELLS, IN FEET S-3164 East 1321.54
L 107.44 864.57 19.7 7.17 4.29 204.86 113.54 10 C 10
HU FM QU HF IDEA CYCLES G-3257A G-3258A G-3773 G-3816 G-3817 G-3772 No No No No No No DBI DBI DBI DBI DBI DBI PF data data data data data data
NGVD 1929 Q5 HFC5e NGVD 1929 Q4 HFC4
MIAMI LS HFC3b Q3 -10 -10 HFC3a
HFC2h -20 HFC2g3 -20 HFC2g2 Q2 HFC2g1
TION HFC2e2
A -30 YNE AQUIFER -30
BISCA HFC2d
TIVE TO NGVD 1929 ?
TIVE TO NGVD 1929 -40 -40
HFC2c2
FORT THOMPSON FORM -50 ? -50 Q1 HFC2b ?
TITUDE, IN FEET RELA
Reef TITUDE, IN FEET RELA
AL -60 Reef -60 HFC2a AL
-70 -70
TION
A
-80 No -80 DBI data No
AMIAMI FORM DBI
T data
SEMICONFINING UNIT -90 -90 EXPLANATION DBI DIGITAL BOREHOLE IMAGE G-3773 G-3816 G-3817 PORE PORE CLASS I FM FORMATION CLASSES Road HFC HIGH-FREQUENCY CYCLE 11.46 Feet OF THE PORE CLASS II HU HYDROGEOLOGIC UNIT BISCAYNE LS Service LIMESTONE AQUIFER PORE CLASS III S-3164 PF PEAT AND FILL S-3163 A A' QU Q-UNIT (Perkins, 1977) AGGRADATIONAL G-3772 G-3257A G-3258A HFC BOUNDARY--Dashed SUBTIDAL CYCLE where uncertain IDEAL UPWARD-SHALLOWING 0 250 500 FEET MUNICIPAL PRODUCTION WELL, CYCLES PARALIC CYCLE UPWARD-SHALLOWING 0 50 100 METERS CASED SECTION HAS COLOR FILL AND OPEN-HOLE INTERVAL NO FILL SUBTIDAL CYCLE
Figure 13. Hydrostratigraphic correlation section A-A’ between the S-3163 and S-3164 production wells, including six digital image logs from observation and injection wells at the Northwest Well Field. Black or very dark areas on the digital optical image logs typically indicate large-scale vuggy porosity. Inset map shows location of section A-A’ within a small area of the well field. Most of the highly porous areas of the aquifer are within stratiform touching-vug porosity zones of pore class I. 40 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
39
Inter-burrow Ground-water porosity storage zone
ACE
40
41 Major ground-water
BELOW LAND SURF , flow and transport zone
IN FEET Figure 14. Digital image of a borehole wall that 42 spans a highly porous and permeable stratiform DEPTH HFC2e2 ground-water flow zone at the base of high- Intra-burrow Ground-water porosity frequency cycle HFC2e2 in well G-3816 (figs. 2 storage zone HFC2d and 13. The dashed line represents the boundary and flooding surface that separates high- 360 DEGREE VIEW OF BOREHOLE WALL frequency cycles HFC2d and HFC2e2.
The following lithofacies are typically assigned to pore class include thin semivertical solution pipes and fossil molds, class II: (1) skeletal packstone and grainstone, (2) pelecypod which are both typically separate vugs (fig. 12). The solution floatstone and rudstone, (3) quartz sandstone and skeletal pipes have a bed-scale length, and as a result, convey only quartz sandstone, and (4) quartz sand (table 7). The skeletal ground water effectively over very short distances. Mangrove packstone and grainstone and pelecypod floatstone and roots are suspected as the origin for many of the solution pipes rudstone lithofacies commonly occur in the upper part of because they are similar to structures described as fossil man- upward-shallowing subtidal cycles and the middle part of the grove roots by Hoffmeister and Multer (1965), Bain and Teeter upward-shallowing paralic cycles (fig. 10). The two quartzose (1975), and Galli (1991). The matrix of the six lithofacies lithofacies are most common in the Pinecrest Sand Member of assigned to pore class III is commonly micrite (microcrystal- the Tamiami Formation. Interparticle, intraparticle, very small line limestone); consequently, the matrix porosity and perme- moldic porosity, and irregular separate-vug (Lucia, 1999) pore ability of these lithofacies are commonly low (table 7). Thus, spaces characterize most of these lithofacies, which typically these lithofacies tend to retard ground-water movement. On a yield ground-water movement through vug‑to-matrix-to-vug local scale, however, lithofacies assigned to pore class III can connections. Diffuse-carbonate ground-water flow, compared contain bedding‑plane vugs that have a sheet-like geometry with diffuse flow of Shuster and White (1971) and Thrailkill and can represent major conduits that are highly permeable. (1976), characterizes ground-water movement in areas of the Biscayne aquifer assigned to pore class II. Those parts of the aquifer that are principally quartz sand or quartz sandstone Generalized Layering Scheme of Pore Classes and that lack moldic or vuggy porosity also are dominated by diffuse ground-water flow. The hydrogeologic framework of the Biscayne aquifer The following lithofacies are usually assigned to pore shown on plates 1 to 4 is a complex arrangement of the three class III: (1) mudstone and wackestone, (2) Planorbella types of pore classes mapped within a cyclostratigraphic floatstone and rudstone, (3) peloid wackestone and packstone, framework. These two-dimensional views of the hydrogeo- (4) conglomerate, (5) pedogenic limestone, and (6) gastropod logic framework were translated into an eight-layer, three- floatstone and rudstone (table 7). The first two lithofacies dimensional representation of the hydrogeologic framework commonly cap upward-shallowing paralic cycles, and the for the study area (figs. 15 and 16). The uppermost layer peloid wackestone and packstone lithofacies is representa- represents peat, muck, marl, and/or fill, and the underlying tive of the lower aggradational subtidal cycle of the Miami seven layers delineate pore classes I, II, and III (figs. 15 and 16). Limestone (fig. 10). The conglomerate lithofacies is mostly Because of the interbedded, fine scale, and lateral complexity of uncommon, but typically occurs at or near the base of HFC4. some of the pore classes delineated on plates 1 to 4, it is unavoid- The pedogenic limestone lithofacies is associated with cycle able that many of the seven layers representing pore classes tops and is the product of diagenesis or deposition of calcrete in the three-dimensional model include two or three different during subaerial exposure. Porosity types common to this pore types of pore classes in the two-dimensional views. Therefore, Hydrogeologic Framework for Model Representation of the Biscayne Aquifer 1
C-1W Canal L-31N Canal L-29 Canal
L-30 Canal 10
0
-10 North
TIVE TO NGVD 1929 -20
-30
-40 C-9 Canal -50 Layer 2 Layer -60 3 Layer Layer 1 TITUDE, IN FEET RELA 4
AL
Layer 6 Layer Layer 5 7
Layer 8
0 5 10 MILES
0 5 10 15 KILOMETERS
EXPLANATION
PEAT, MUCK, MARL, AND/OR FILL PORE CLASS III PORE CLASS II
PORE CLASS I
Figure 15. Three-dimensional conceptual hydrogeologic model of the Biscayne aquifer for the study area in north-central Miami-Dade County. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
C-1W Canal L-31N Canal L-29 Canal L-30 Canal
North
C-9 Canal
Layer 1
Layer 2
Layer 3
Layer 4
Layer 5
Layer 6
Layer 7
Layer 8
0 5 10 MILES EXPLANATION
0 5 10 KILOMETERS PEAT, MUCK, MARL, AND/OR FILL PORE CLASS III PORE CLASS II PORE CLASS I
Figure 16. An exploded view showing much of the geometry of the upper surfaces of the three-dimensional conceptual hydrogeologic model of the Biscayne aquifer for the study area in north-central Miami-Dade County. Refer to figure 15 for vertical scale. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer figures 15 and 16 are simplified interpretations of the two- most part of the Fort Thompson Formation. The upper surface dimensional framework shown on plates 1 to 4. For example, of layer 3 generally dips to the east or southeast, but also dips permeable zones representative of pore class I that seem to to the west, in an area to the southwest of the intersection of be more hydraulically connected laterally than isolated are Krome Avenue and Tamiami Trail (fig. 19). Layer 3 generally combined into regional units. The delineation of three distinct is between 2 and 4 ft thick throughout the study area (fig. 20). relatively high-permeability layers (figs. 15 and 16, repre- This low-permeability layer has been evaluated in numerous sented by pore class I) is supported by measured differences in studies (Klein and Sherwood, 1961; Shinn and Corcoran, vertical hydraulic gradient for permeable zones contained in 1988; Guardiario, 1996; Brown and Caldwell Environmental HFC5e and HFC3a and permeable zones in the lower part of Engineers and Consultants, 1998; Genereux and Guardiario, the Biscayne aquifer in the southwestern part of the study area 1998; Nemeth and others, 2000; Sonenshein, 2001; (Cunningham and others, 2004c). Cunningham and others, 2004b; Krupa and Mullen, 2005). The Biscayne aquifer is conceptualized as three sub- Layer 4 is characterized by the upper zone of pore aquifers of relatively high permeability (layers 2, 5, and 8), class II, and generally is equivalent to the lower and middle which are interlayered with two layers of relatively moderate parts of HFC3b and the middle and upper parts of HFC3a. permeability (layers 4 and 7) and two layers of relatively low The upper surface of layer 4 has a slight broad dip toward permeability (layers 3 and 6) as shown in figures 15 and 16. the southeast (fig. 21). The thickness of this layer varies The two uppermost relatively high-permeability layers (2 throughout the study area, ranging from 0 to 15.4 ft (fig. 22). and 5) are approximately equivalent to HFC5e and HFC3a Layer 4 generally is thin in the northern and southwestern and have good physical connection in and around the study parts of the study area, however, and thickens to the north- area. The two relatively moderate permeability layers (4 and western and southeastern parts (fig. 22). 7) representing pore class II are conceptualized as containing Layer 5 is characterized by the middle zone of pore mostly diffuse-carbonate ground-water flow. Both layers are class I, and generally corresponds to the base (or near the hypothesized to contain much of the ground-water storage in base) of HFC3a. The approximate direction of the dip of the the Biscayne aquifer and less important in terms of regional upper surface of layer 5 is toward the south in the northern ground-water flow. Layers 3 and 6 representing pore class III part of the study area and toward the southeast in the southern are conceptualized as relatively low-permeability layers that part of the study area (fig. 23). The layer is thickest (almost generally include: (1) HFC4 and the top of HFC3b; and (2) the 10 ft) in the northeastern part of the study area, but generally base of HFC3b, and locally, the top of HFC2h. Both layers are is between 1 and 3 ft thick over much of the study area and considered to leak vertically and inhibit horizontal movement locally absent (fig. 24). of ground water and have only a minor role, if any, in the Layer 6 is characterized by the lower zone of pore horizontal movement of ground water, except in areas where class III and occurs at the base of HFC3a and locally at the bedding‑plane vugs are present. In summary, the mapping uppermost part of HFC2, spanning the top of HFC2 and of the altitudes and thicknesses of pore-class layers within a HFC3a. The upper surface of layer 6 generally slopes toward simplified conceptual model of the Biscayne aquifer could be the southeast or east in the study area (fig. 25). The layer is used as a template for more reliable numerical ground-water thin or absent in the northeastern part of the study area, and model layering than previously possible (figs. 15 and 16). in general, about 1 to 2 ft thick over the rest of the study area (fig. 26). Altitudes and Thicknesses of Hydrogeologic Layer 7 is characterized by the lower zone of pore class II Layers and is equivalent to the upper part of HFC2 and can include HFC2e to HFC2h. The upper surface of layer 7 generally dips Layer 1 is composed of peat, marl, muck, and fill and toward the south and southeast (fig. 27). The layer is thinnest layers 2 to 8 are characterized by pore class I, II, or III. Pore on the western part of the study area and thickens toward the class I is characteristic of layer 2 and generally corresponds east, especially to the northeast where the thickness exceeds to HFC5e, the Q5 unit of Perkins (1977) or Q5e of Multer 30 ft (fig. 28). and others (2002). In general, the upper surface of layer 2 is Layer 8 is characterized by the lower zone of pore class I highest in the area of the NWWF (fig. 17). North of the well and is equivalent to the lower part of HFC2 and can include field, the surface dips slightly to the south; south of the well HFC2d to HFC2a. This layer includes much of the open-hole field, the surface generally dips northward. Layer 2 generally intervals of production wells at the NWWF and West Well is thinnest in the northwest and thickens southeastward to Field (fig. 2). Layer 8 is thickest in the northwestern part of more than 15 ft (fig. 18). the study area and in the vicinity of the NWWF. In general, the Layer 3 is characterized by the upper zone of pore upper surface of layer 8 dips from west to east at about 5 ft per class III, and mostly is inclusive of HFC4, the Q4 unit of mile (fig. 29). The thickness of this layer ranges from about Perkins (1977), and the uppermost part of HFC3b; that is, this 9 ft to 45 ft (fig. 30). The lower surface of layer 8 generally layer can span the base of the Miami Limestone and upper- dips toward the east (fig. 31). A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°25´
3 BROWARD COUNTY C-9 MIAMI-DADE COUNTY 4.2 3.0 3.0
L-67A 4 5 4.0 4.7 4.8 L-67C 5.0 C-6 1.5 4.2 3 4.9 2 2.3 4.0 2.5 4 4.0 2.8 2 3.0
L-30N 3 1.2 0.8 2 2.0 0 0 1.3 0 3 3.9 1.3 1 0.5 3 3.0 2.4 Northwest Well Field
4.0 4 1.0 2 2.0 3
1 5.5 2.0 4 5 1.3 L-29 3.6 C-4 5.0 6.3 4.0
1.0 4.9 7.1 6 2.2 5 25°45´ 2 7 3.3 6.2 3 4.2 3.9 5.5 7.0 4 6.0 6 7.8 4.8 7.0 7 8.5 7.0 8.0 EXPLANATION 8 2.9 5.5 STUDY AREA 6 3 4 LINE OF EQUAL ALTITUDE--Shows altitude of 5.9 6 5 the top of the upper zone of pore class I of the 6.5 4 Biscayne aquifer, in feet above NGVD 1929. 5.0 Interval is 1 foot 5 WELL LOCATION AND ALTITUDE--Number is 6.0 5.0 4.5 the altitude of the top of the upper zone of 6.5 6.0 5.8 pore class I of the Biscayne aquifer, in feet 6.0 above NGVD 1929. See figure 2 for all local
L-31N well numbers 0 1 2 3 MILES 7.5
7 0 1 2 3 KILOMETERS C-1W Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 17. Altitude of the top of the upper zone of pore class I of the Biscayne aquifer. This zone is shown as layer 2 in figure 15. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
80°25´
BROWARD COUNTY 1.6 3.2 C-9 7.6 MIAMI-DADE COUNTY
6 L-67A
4.9 0.4 3.6 4 L-67C 2.3 2 C-6 4 2.7 4.4 1.9 4 3.8 3.4 2.7
2 3.4 1.2 4.7 Northwest Well Field 2.2
L-30N 4.5 3.0 3.4 5.0 3.5 3.8 3.4 0.6 4 2 5.4 2.1
4.4 6.5 3.4 6
9.0
4.3
4.2 7.7 L-29 5.7 4.9 7.8 8.9 C-4 6.4 6.2 6 25°45´ 6.5 8 7.2 8.3 8 10 10 11.6 8.9 7.8 8 10.7 14.8 8 7.0 9.113.0 6 10 12 5.5 8.2 11.7 10 EXPLANATION 4.1 6 9.3 STUDY AREA 9.7 8.2 8 6 LINE OF EQUAL THICKNESS--Shows thickness of the upper zone of pore class I of the Biscayne 8.1 10 12 14 aquifer, in feet. Interval is 1 foot
L-31N 1.6 WELL LOCATION AND THICKNESS--Number is the 9.8 13.2 thickness of the upper zone of pore class I of the 10.4 15.1 Biscayne aquifer, in feet. See figure 2 for all local 11.3 10.8 13.5 well numbers 0 1 2 3 MILES 12 13.1
C-1W 0 1 2 3 KILOMETERS
Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 18. Thickness of the upper zone of pore class I of the Biscayne aquifer. This zone is shown as layer 2 in figure 15. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°25´
BROWARD COUNTY 2.6 -0.2 C-9 MIAMI-DADE COUNTY Absent 0 L-67A 4 4 4.4 2.4 Absent L-67C 2 1.4 2.4 C-6 -1.2 0 -0.7 0.5
-0.2 -1.6 Absent
-0.6 -1.7
-3.0 0 -3.7 L-30N -3.0 -1.5 -5.0 -1.6 2 -4.9 0.5 2.4 -2.1 0.3 -2
Northwest 0.6 -3.4 -4.5 Well Field -4
-3.5 -2 -2.3 -1.4 Absent -5.2 L-29 C-4 -4.9 Absent -0.6 -0.8 -0.1 Tamiami Trail 25°45´ -4.3 -2 -5.0 -4 -4 -1.0 -6 -7.5 -6 -4.7 -5.0 -2.3 -7.8 -0.8 -2.1 -2 -4.5 -8 -0.7 -4 -0.2 -4.7 -4 -2 EXPLANATION -3.8 -1.8 STUDY AREA -4 LINE OF EQUAL ALTITUDE--Shows altitude of -3.8 Absent the top of the upper zone of pore class III of the Biscayne aquifer, in feet below NGVD 1929. -3.0 Interval is 2 feet. Dashed where absent WELL LOCATION AND ALTITUDE--Number is Absent -3.5
L-31N -8.4 the altitude of the top of the upper zone of pore -3.9 -4 -9.3 class III of the Biscayne aquifer, in feet below -5.3 -4.8 NGVD 1929. See figure 2 for all local well
numbers ve.
A 0 1 2 3 MILES -5.6
C-1W 0 1 2 3 KILOMETERS Krome Krome Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 19. Altitude of the top of the upper zone of pore class III of the Biscayne aquifer. This zone is shown as layer 3 in figure 15. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
80°25´
BROWARD COUNTY C-9 0 MIAMI-DADE COUNTY 2.9 2.2
L-67A 2.0 2 0 0 2 L-67C 1.4 2.4 C-6 3.9 0.7 1.3 3.8 6
0.2 6.5
0 4.9 4 0 4 5.2 2 1.8 2 1.2 1.7 4.1 2.5 4 4 5.3 6.8 4.5 6.1 3.5 1.7 6 Northwest
2.9 5.6 Well Field L-30N 1.6
0
4 2 4.3 2.5 5.3 1.5 L-29 0 C-4 0 4.3
1.1 1.5 3.8 0 2.0 25°45´ 2 2.5 2 3.3
2.8 1.2 4.5 1.5 1.6 3.8 6 1.6
7.5 0.7 2 4.5 2 3.7 4.3 EXPLANATION 4 3.7 STUDY AREA 0 0.4 LINE OF EQUAL THICKNESS--Shows thickness of 0 2 4.0 the upper zone of pore class III of the Biscayne aquifer, in feet. Interval is 2 feet 2 1.6 WELL LOCATION AND THICKNESS--Number is the 3.6 0 0.8 thickness of the upper zone of pore class III of the 1.8 0.3 2.4 1.6 Biscayne aquifer, in feet. See figure 2 for all local 0 well numbers
2 0 1 2 3 MILES L-31N
0.3 C-1W 0 1 2 3 KILOMETERS
Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 20. Thickness of the upper zone of pore class III of the Biscayne aquifer. This zone is shown as layer 3 in figure 15. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°25´
BROWARD COUNTY -0.3 C-9 -4.6 MIAMI-DADE COUNTY Absent -4
L-67A 2 2.0 1.0 0 -0.9 L-67C Absent C-6 -1.6 -0.6 -3.3 -1.9 -2
-0.4 -8.0 -4 -8 2.8 -6 2 -5.5 -6.9 0 -6 -4 -2.8 -2 -4.8 -4 -3.7 -8 -9.1 -4.0 -4 -7.4 -8.4 -8.4 -4.0 -3.7 Northwest -1.4 Well Field -10
-6.3 L-30N -10.1 -1.0
-7.8 -8 -4.8 -4 -6.7 -0.7 -6.3 L-29 -5.1 -2.1 C-4 -9.2 -2 -2.3 -3.7 -6.4 25°45´ -4 -7.5 -6 -4.4 -6 -8 -10 -6.5 -5.1 -12 -6.2 -8 -8.9 -12.0 -4 -3.0 -3.7 -8.2 -5.1 -9.2 -3.9 -8.1 EXPLANATION -5.5 -4 STUDY AREA -2 -4 LINE OF EQUAL ALTITUDE--Shows altitude of -4 -6 -4.2 the top of the upper zone of pore class II of the -1.7 Biscayne aquifer, in feet below NGVD 1929. -7.0 -10 Interval is 2 feet. Dashed where absent WELL LOCATION AND ALTITUDE--Number is -8.9 -3.8 -7.2 the altitude of the top of the upper zone of -11.1 pore class II of the Biscayne aquifer, in feet -4.2 -10.0 -9.9 below NGVD 1929. See figure 2 for all local well numbers
L-31N -8 0 1 2 3 MILES -5.9
C-1W 0 1 2 3 KILOMETERS Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 21. Altitude of the top of the upper zone of pore class II of the Biscayne aquifer. This zone is shown as layer 4 in figure 15. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
80°25´
BROWARD COUNTY 0.3 0 C-9 4.3 MIAMI-DADE COUNTY
0 L-67A
1.5 2 10 4.7 0 L-67C 4 6 6 10.8 5.3 8 4.8 8.5 8.5 9.3 3.9 C-6 6
15.4 8 14 2 6 12 2.0 4 8.8 3.9 10 8 3.1 6 4 8 9.1 9.8 4.6 5.3 4.8 5.9 8 6.9 5.8 Northwest 10 10.4 Well Field 4.1 6.4
6.5 L-30N 9.1 6.1 8 8 9.3 6.5 12.6 8.1 L-29 3.1 8.7 9.1 9.5 C-4
25°45´ 8.5 6 8.0 10.8 4 10 4.9 10.4 12.1 10.1 11.9
2.8 10.0 12 3.4 11.1 9.4 3.3 EXPLANATION 13.3 12 STUDY AREA 11.3 10.4 10 LINE OF EQUAL THICKNESS--Shows thickness of 8.6 10 the upper zone of pore class II of the Biscayne 4.2 aquifer, in feet. Interval is 2 feet 8.5 4 6 8 11.4 8 12.6 WELL LOCATION AND THICKNESS--Number is the 5.9 9.2 7.5 thickness of the upper zone of pore class II of the Biscayne aquifer, in feet. See figure 2 for all local well numbers
L-31N 0 1 2 3 MILES
9.0 0 1 2 3 KILOMETERS C-1W
Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 22. Thickness of the upper zone of pore class II of the Biscayne aquifer. This zone is shown as layer 4 in figure 15. 50 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°25´
BROWARD COUNTY -0.6 -2.3 C-9 Absent MIAMI-DADE COUNTY 0 L-67A -0.9
-9.8 -2 -5.6 L-67C -1.0 -4 -10 -6 -6.9 -8 -10.4 -8.1 -9.1 -9.7 -10 -12.0 C-6
-12.6 -12.6
-7.5
-8 -11.5 -8.0 -10.8 L-30N
-10 -10 -13.8 -13.7 -12.7 -13.7 -12 -13.2 Absent -9.4 -14.3 -11.8 -14 -12 Northwest -8 Well Field -7.5 -12.7 -14.2
-10
-16.8 -16 -10.9 -8.7 -10 -18 -10.8 -14.9 L-29 -8.1 C-4 -12.8 -18.6 -15.6 -13.3 -12 25°45´ -14.9 -15.5 -14 -15.1 -16.3 -16 -20 -18.4 -15.4 -16.9 -21.0 -13.0 -14.8 -10.9 -14.6 -12.6 -15.3 -15.9 EXPLANATION -11.3 STUDY AREA -13.0 -4 LINE OF EQUAL ALTITUDE--Shows altitude of
-12.8 -18 the top of the middle zone of pore class I of the Biscayne aquifer, in feet below NGVD 1929. -14
-11.2 -12 -16 Interval is 2 feet. Dashed where absent WELL LOCATION AND ALTITUDE--Number is -21.2 -13.0 -18.6 the altitude of the top of the middle zone of -10.1 pore class I of the Biscayne aquifer, in feet -20 below NGVD 1929. See figure 2 for all local -15.6 well numbers
L-31N 0 1 2 3 MILES
-14.9 C-1W 0 1 2 3 KILOMETERS Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 23. Altitude of the top of the middle zone of pore class I of the Biscayne aquifer. This zone is shown as layer 5 in figure 15. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer 1
80°25´
BROWARD COUNTY 2.6 3.4 C-9 0 0 MIAMI-DADE COUNTY 1 2 3 L-67A 4.4 8 9 1.8 6 L-67C 4.0 7 9.9 C-6 4 5 3 1.3 1.8 0.2 2 1.7 0.5 2.4
L-30N 1 1.7 2 2.5 1.8 1.8 4.0 3 2.3 0 4 1.2 0 1.3 0 1 1.4 0.5 1.9 1 1.4 Northwest Well Field 1.6 2 5.3 5 2.1 4 2
2 3 3 1 0.9
4 5 1.3
6 1 2.7 L-29 2.2 2.0 1.1 1.9 C-4 6.6 0.6 1.7 25°45´ 3.6 2.7 1.1 3.2 2 1.6 2.0 4 4.6 3.8 3.6 1.3 1.2 1.3 3 2 1.7 1.6 3 EXPLANATION 3.9 2.5 STUDY AREA 1.3 1.5 6 LINE OF EQUAL THICKNESS--Shows thickness of 1.5 2 the middle zone of pore class I of the Biscayne aquifer, in feet. Interval is 1 foot 3 1.6 WELL LOCATION AND THICKNESS--Number is the 3.8 3.4 2 thickness of the middle zone of pore class I of the 3.4 1.7 Biscayne aquifer, in feet. See figure 2 for all local 3 well numbers
0 1 2 3 MILES L-31N
2 C-1W 0 1 2 3 KILOMETERS 1.6 Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 24. Thickness of the middle zone of pore class I of the Biscayne aquifer. This zone is shown as layer 5 in figure 15. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°25´
BROWARD COUNTY Absent Absent C-9 Absent MIAMI-DADE COUNTY
L-67A Absent Absent -11.6 -15.4 L-67C C-6 -8.2 -12.2 -8.3 -12 Absent
-10 -10.9 Absent
-14.3 -10.0 Absent -14 Absent
L-30N Northwest -12.0 Absent -14.9 -13.7 Well Field -12 -13.7 -10.9 -10.8 -13.9 -16.2 -13.2 -16 -12 -14 -10 -9.6 -15.8 Absent
-12 -17.8 -12.2 -18 -12.8 -10 -14.7 -13.4 -16.0 L-29 -9.9 -20 C-4 -17.8 -16.6 -20.6 -18.5 25°45´ -14 -18.2 -16 -20.9 -20 -16.2 -18 -19.0 -20.1 -20.0 -16.9 -23.0 -14 -16.0 -13.0 -15.9 -14.3 -16.9 -14 -15.3 EXPLANATION -16 -18.4 STUDY AREA -14.4 -16 LINE OF EQUAL ALTITUDE--Shows altitude of -14.1 -20 the top of the lower zone of pore class III of the
-20 -22 Biscayne aquifer, in feet below NGVD 1929. -12.7 Interval is 2 feet. Dashed where absent -18 WELL LOCATION AND ALTITUDE--Number is the -19.0 altitude of the top of the lower zone of pore -14.0 -22.0 class III of the Biscayne aquifer, in feet below Absent NGVD 1929. See figure 2 for all local well numbers
0 1 2 3 MILES L-31N
0 1 2 3 KILOMETERS
-16.5 C-1W Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 25. Altitude of the top of the lower zone of pore class III of the Biscayne aquifer. This zone is shown as layer 6 in figure 15. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
80°25´
BROWARD COUNTY 0 0 C-9 0 MIAMI-DADE COUNTY
L-67A 0 0 0 0.3 L-67C 0.7 C-6 0.9 0.8 0 0.9 0 0
0.7 L-30N 0.7 1 0 1.5 0 4 2 Northwest 4.3 3 0 0.3 2.8 Well Field 0 0.6 3.0 2 1.1 0.1 2.3 1.8 2 0 0 3.0 3.6 1
2
3 3 1.5 3.9
2.9 3 2 L-29 3.1 3.0 3.0 C-4
2.4 2 1.5 1.7 25°45´ 3.8 4.0 1 1.3 1.9 0.5 1.8 0.3 4 0.1 4 1.7 4.4 3 4.0 3.6 3.7 1.0 EXPLANATION 2.3 2.6 1 2 STUDY AREA 4.2 4.3 3 2 LINE OF EQUAL THICKNESS--Shows thickness of 4 the lower zone of pore class III of the Biscayne 3.4 3 2 aquifer, in feet. Interval is 1 foot 1.6 WELL LOCATION AND THICKNESS--Number is the 2 1.8 1 0 thickness of the lower zone of pore class III of the 2.0 1.3 Biscayne aquifer, in feet. See figure 2 for all local 0 well numbers
0 1 2 3 MILES L-31N
C-1W 0 1 2 3 KILOMETERS 1.7 Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 26. Thickness of the lower zone of pore class III of the Biscayne aquifer. This zone is shown as layer 6 in figure 15. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°25´
BROWARD COUNTY -3.2 -6.0 C-9 -8.9 MIAMI-DADE COUNTY
-4 L-67A -3.5 -6 -8 -5.0 -12 -14 -12.3 -15.7 L-67C -10 -9.1 -9.3 -10 -13.0 -14 -10.8
-12 -11.7 -14.4 C-6
-15.0 -11.5 -12.6 -14 -12 -16 -16.3 L-30N -14 -13.3 -14 -16.5 -16 -16 -15.2 -16.5 -14.5 -14.8 -14 -13.0 -16.3 -13.8 -14.9 -16 Northwest Well Field -18 -14 -13.2 -17.9 -18.8
-20 -19.2 -15.9 -16.1 -14 -17.5 -12 L-29 -17.7 -23.5 C-4 -20.3 -16.4 -11.4 25°45´ -22.3 -22.1 -16 -17.5 -22 -20 -22.0 -18 -22.7 -20.3 -19.1 -18.5 -18 -23.5 -19.9 -17.3 -16.9 -17.9 -20.6 EXPLANATION STUDY AREA -17.5 -20 -21.0 -20 LINE OF EQUAL ALTITUDE--Shows altitude of the top of the lower zone of pore class II of the -18.4 -18.6 Biscayne aquifer, in feet below NGVD 1929. Interval is 2 feet
-16.1 -18 -16 -24 WELL LOCATION AND ALTITUDE--Number is the
-22 altitude of the top of the lower zone of pore class II of the Biscayne aquifer, in feet below -15.3 -23.9 NGVD 1929. See figure 2 for all local well -20.8 -22.9 numbers
0 1 2 3 MILES L-31N
-18.2 C-1W 0 1 2 3 KILOMETERS Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 27. Altitude of the top of the lower zone of pore class II of the Biscayne aquifer. This zone is shown as layer 7 in figure 15. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
80°25´
BROWARD COUNTY 4.8 C-9 25.7 MIAMI-DADE COUNTY 16.9 20 L-67A 17.5 22.5 5 7.5 20.5 25 27.5 7.7 30 30.2 L-67C
12.5 4.2
10
C-6 15 17.6 25
L-30N 17.8 19.0 2.5 15 13.9 15.3 13.8 23.0 2.3 7.6 Northwest 5 13.8 Well Field
7.5 20 22.5 8.6 13.5 10
17.5 12.5
15
12.8 L-29 C-4
5.7 25°45´ 5.0
6.3
7.6
5.8 EXPLANATION 6.4 STUDY AREA 10 12.5 LINE OF EQUAL THICKNESS--Shows thickness of 10 the lower zone of pore class II of the Biscayne 7.5 aquifer, in feet. Interval is 2.5 feet
12.6 WELL LOCATION AND THICKNESS--Number is the thickness of the lower zone of pore class II of the 13.8 Biscayne aquifer, in feet. See figure 2 for all local well numbers
L-31N 0 1 2 3 MILES 9.4 C-1W 0 1 2 3 KILOMETERS
Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 28. Thickness of the lower zone of pore class II of the Biscayne aquifer. This zone is shown as layer 7 in figure 15. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°25´
BROWARD COUNTY -8.0 -22.9 C-9 -34.6 MIAMI-DADE COUNTY -20 L-67A -28 -24.0 -32 -35.2
L-67C -16 -20.0 -8 C-6 -36
-13.3 -24
-32.0
-12
-29.3 -28 -20.0 L-30N -24 -30.2 -20 -28.8 -28.3 -16.1 -38.1 -20.6 -28.6 Northwest Well Field
-24 -20 -28 -32.2
-21.8 -32 -36
-40
-44 L-29 -45.7 C-4
-28.1 25°45´
-27.1 -44 -40
-28.2
-24.9
-24 -32
-28 EXPLANATION -36 -23.3 STUDY AREA -20 LINE OF EQUAL ALTITUDE--Shows altitude of -24.7 the top of the lower zone of pore class I of the Biscayne aquifer, in feet below NGVD 1929. Interval is 4 feet -18.3 WELL LOCATION AND ALTITUDE--Number is the altitude of the top of the lower zone of -37.7 pore class I of the Biscayne aquifer, in feet below NGVD 1929. See figure 2 for all local well numbers
0 1 2 3 MILES L-31N
-27.5 C-1W 0 1 2 3 KILOMETERS Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 29. Altitude of the top of the lower zone of pore class I of the Biscayne aquifer. This zone is shown as layer 8 in figure 15. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
80°25´
BROWARD COUNTY 44.6 C-9 12.1 MIAMI-DADE COUNTY 40
L-67A 15 28.0 20 30 L-67C 25.8 35 C-6 32.2
25 L-30N 18.7 20
33.2 37.8 30 35.2 35 32.0 30.1 29.2 38.9 27.4 Northwest Well Field 25 18.8 20
15
L-29 C-4 9.3 14.2 10 25°45´ 10.5 15 15.4
9.3 10 EXPLANATION 11.2 STUDY AREA 14.8 LINE OF EQUAL THICKNESS--Shows thickness of 10 the lower zone of pore class I of the Biscayne 15 aquifer, in feet. Interval is 5 feet 21.6 WELL LOCATION AND THICKNESS--Number is the thickness of the lower zone of pore class I of the Biscayne aquifer, in feet. See figure 2 for all local 17.1
L-31N well numbers 0 1 2 3 MILES
0 1 2 3 KILOMETERS
19.3 C-1W
Base from U.S. Geological Survey digital data, 1972 Universal Transverse Mercator projection, Zone 17, Datum NAD 83
Figure 30. Thickness of the lower zone of pore class I of the Biscayne aquifer. This zone is shown as layer 8 in figure 15. A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
80°25´
-46.6 BROWARD COUNTY -52.6 C-9 MIAMI-DADE COUNTY -48 -5 -50 L-67A 0 -53.7 -52 -4 8 -54 -4 -61.0 -56 L-67C 6 -60 -58 -45.5 C-6 -60
-66 -48.0
-62.0
-67.0 -67.9 L-30N -67.2 -70.1 -46.7 -49.8 -55.9 -44 -4 -68 6 -6 -56 -58 -6 -42 4 Northwest -6 2 -6 Well Field 0 6 -40 0
8 2 -39.4 -5 4
-4 -5
-5
L-29 C-4 -56.4 -42.3 -44 25°45´ -47.0 -46 -43.6
-36 -34.2
0 -42 EXPLANATION -34.5 4 -4 STUDY AREA -38 -4 6 0 -20 LINEOFEQUAL ALTITUDE--Shows altitude of -39.5 -4 8 -4 -5 the base of the lower zone of pore class I of the Biscayne aquifer, in feet below NGVD 2 4 1929. Interval is 2 feet -5 -5 -18.3 WELL LOCATION AND ALTITUDE–Number is the altitude of the base of the lower zone of -54.8 pore class I of the Biscayne aquifer, in feet below NGVD 1929. See figure 2 for all local well numbers
L-31N 0 1 2 3 MILES -46.8
C-1W 0 1 2 3 KILOMETERS
Figure 31. Altitude of the base of the lower zone of pore class I of the Biscayne aquifer. This zone is shown as layer 8 in figure 15. Hydrogeologic Framework for Model Representation of the Biscayne Aquifer
Borehole-Fluid Flow raphy. The porosity of pore class I is typically characterized by touching vugs that form highly permeable stratiform passage- Vertical borehole flow was identified to test the hypoth- ways and less widespread bedding‑plane vugs, thin solution esis that laterally extensive units characterized by pore pipes, and cavernous porosity. The size, shape, and spatial class I are responsible for most of the ground-water flow in distribution of touching‑vug porosity within the Biscayne the Biscayne aquifer. Borehole-fluid flow was detected in aquifer can be mapped within the context of the high-fre- conjunction with the acquisition of borehole-flowmeter data, quency cyclostratigraphic framework because these attributes fluid-conductivity data, and fluid-temperature data (table 8) commonly occur in the lower part of the HFCs above flooding and also digital optical borehole images and computed vuggy surfaces, which facilitates well-to-well correlation of highly porosity data. For the logs included in table 8, borehole-fluid porous zones. These highly porous zones commonly occur at temperature ranged from 71.6 to 88.9 °F, and borehole-fluid the base of the paralic and subtidal upward-shallowing cycles conductivity ranged from 336 to 807 µS/cm for measurements of the Fort Thompson Formation and throughout the upper- within the Biscayne aquifer. Intervals of boreholes where most subtidal aggradational cycle of the Miami Limestone changes in borehole flow and fluid conductivity or fluid (fig. 10). temperature or both are sharp have been identified as zones of Pore class II is distinguished by interparticle and sepa- the boreholes where there is inflow or outflow of water. rate-vug porosity within the rock matrix and mostly contains In some instances, abrupt variations in fluid conduc- diffuse-carbonate ground-water flow (Shuster and White, tivity, temperature, or both corresponded to sharp changes in 1971; Thrailkill, 1976; Martin and Screaton, 2001). These flowmeter velocities; these flow zones mostly occurred at the two pore types relate to specific lithofacies at the middle of base of the HFCs (table 8). Two preferential flow zones were upward-shallowing cycles and the upper part of ideal subtidal most likely present in the upper part of the Biscayne aquifer in upward-shallowing cycles of the Fort Thompson Formation. HFC3a and HFC5e, seven preferential flow zones were identi- The porosity of pore class III is typically distinguished fied as important in the lower part of the Biscayne aquifer, by separate vugs, such as Planorbella molds, within a very and five zones were identified in the Biscayne aquifer where low-permeability micrite matrix that: (1) may be perforated inflow and outflow from the borehole were only delineated by thin semivertical solution pipes of limited vertical extent, locally (fig. 32). Examples from layers 2, 5, and 8 (figs. 15 or (2) may have associated bedding‑plane vugs. The overall and 16) of ground-water inflow into boreholes from prefer- permeability of pore class III is commonly low, but vertically ential flow zones, represented as pore class I on the basis of leaky. Pore class III is commonly associated with micrite-rich digital borehole images, are shown in figures 33, 34, and 35, lithofacies that may cap upward-shallowing cycles of the Fort respectively. Both zones shown in figures 33 and 34 are part of Thompson Formation. hydrogeologic units (figs. 15 and 16, layers 2 and 5) that can The distribution of pore classes I, II, and III in the study be clearly correlated well beyond the limits of the study area. area occurs within predictable vertical and horizontal spatial In conclusion, all of HFC5e, the lower part of HFC3a, patterns. This can be explained by the fact that their manifesta- and various zones in the lower part of the Biscayne aquifer tion is directly related to the vertical assemblage of lithofacies (fig. 32) likely are principal pathways for ground-water flow within HFCs. and solute transport in the Biscayne aquifer. Additionally, It is proposed herein that karstic development of the HFC5e corresponds to the regionally mapped Q5 unit of highly permeable zones at the base of upward-shallowing Perkins (1977), and the lower part of HFC3a occurs near the cycles of the Fort Thompson Formation relates to cyclostratig- base of the Q3 unit of Perkins (1977); both are correlated, raphy and Pleistocene sea-level history. This conclusion is although undocumented, over a large area of Miami-Dade supported by figure 8, which shows that the vertical arrange- County. Many older preferential flow zones (fig. 32) seem to ment of lithofacies and pore classes are linked within the be present throughout the study area, but their extent has not context of ideal HFCs. Formation of secondary porosity been verified. Mapping shows that the preferential flow zones was probably produced by meteoric water flowing through of local extent (fig. 32) probably are not substantial pathways the limestone of the Fort Thompson Formation during its for regional ground-water flow and solute transport. emergence into the vadose zone caused by periodic low stands in sea level that span Pleistocene glacial maximums inferred by Perkins (1977). The possibility exists that these episodic Ground-Water Flow and Pore System Evolution vadose events promoted aggressive dissolution of carbonate grains and depositional textures in the lower part of cycles as Movement of ground water within water-bearing strata a result of perched, concentrated, down-dip flow of meteoric of the Biscayne aquifer occurs within pore classes I, II, and water above flooding surfaces. This focused, low-gradient III (table 7). Each pore class comprises a unique category lateral flow of meteoric water above flooding surfaces is of lithofacies and pore system (figs. 11 and 12, and table 7). postulated due to the presence of relatively low-permeability Carbonate-rock lithofacies and pore systems can be arranged lithologies at cycle tops that underlie flooding surfaces and act within the context of high-frequency carbonate cyclostratig- as baffles or barriers to downward vertical drainage. 60 A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Table 8. Borehole-flowmeter, fluid-conductivity, and fluid-temperature data for wells that fully penetrate the Biscayne aquifer in the study area and collected over uncased, open-hole intervals. [HFC, high-frequency cycle; C, conduit; TV, touching vug; —, no log was made; *Quasi-synoptic log measurements]
Data collection date Inflection depth (feet below land surface) Local HFC or formation contributing Fluid Fluid Fluid Fluid well Heat-pulse Spinner Heat-pulse Spinner flow into or out Porosity type conduc- temp- conduc- temp- identifier flowmeter flowmeter flometer flowmeter of borehole tivity erature tivity erature 9-16-03 — 9-12-03 9-12-03 29.9-29.4 — None None Lower HFC3a C G-3671* 9-16-03 — 9-12-03 9-12-03 46.8-48.0 — None None Lower HFC2e2 TV 3-16-04 — 3-16-04 3-16-04 45.9-46.9 — None None Lower HFC2e2 TV 3-8-04 — 3-8-04 3-8-04 8.5-11.5 — None None Lower HFC5e TV and C G-3733 3-8-04 — 3-8-04 3-8-04 17.0-20.5 — None None Lower HFC2h TV 3-8-04 — 3-8-04 3-8-04 22.4-25.0 — None None Lower HFC2g3 TV 12-20-02 — — — 16.1-18.4 — — — Lower HFC3a TV 12-20-02 — — — 26.5-29.6 — — — Lower HFC2g2 TV 12-20-02 — — — 45.9-51.1 — — — Middle HFC2c2 TV 1-2-03 — — — 17.0-18.0 — — — Lower HFC3a TV G-3770 1-2-03 — — — 49.1-51.2 — — — Middle HFC2c2 TV 1-8-03 — — — 16.0-18.0 — — — Lower HFC3a TV 1-8-03 — — — 26.4-29.5 — — — Lower HFC2g2 TV 1-8-03 — — — 49.2-51.1 — — — Middle HFC2c2 TV 12-26-02 — — — 16.0-16.6 — — — Lower HFC3a TV 12-26-02 — — — 26.1-23.5 — — — Lower 2g3 TV 12-26-02 — — — 34.5-41.1 — — — Lower HFC2f & HFC2e2 TV and C 12-26-02 — — — 41.1-45.1 — — — Lower HFC2d TV 12-26-02 — — — 54.5-55.0 — — — Uppermost Tamiami Formation TV G-3771 12-30-02 — — — 16.0-17.1 — — — Lower HFC3a TV 12-30-02 — — — 22.0-24.0 — — — Lower HFC2g3 TV Lower HFC2f, Lower HFC 2e2, 12-30-02 — — — 33.1-45.3 — — — TV and C Lower HFC2d 12-30-02 — — — 49.1-54.5 — — — Lower HFC2c2 TV 1-8-03 — — — 22.5-25.9 — — — Lower HFC2g3 TV 1-8-03 — — — 34.5-42.0 — — — Lower HFC2f, Lower HFC2e2 TV and C 8-7-03 — — — 20.5-23.5 — — — Lower HFC5e TV and C 8-7-03 — — — 29.0-29.5 — — — Upper HFC3a C? 8-7-03 — — — 32.0-35.5 — — — Lower HFC3a TV 8-7-03 — — — 38.8-39.1 — — — Upper HFC2h Matrix G-3778 8-7-03 — — — 41.0-46.5 — — — Lower HFC2g3 TV 8-7-03 — — — 48.0-49.5 — — — Lower HFC2g2 TV? 8-30-03 — — — 20.0-25.5 — — — Lower HFC5e, upper HFC3b TV and C 8-30-03 — — — 25.5-29.1 — — — Upper HFC3a TV and C? 8-30-03 — — — 31.8-35.5 — — — Lower HFC3a TV 8-11-03 — 8-11-03 8-11-03 19.0-22.6 — None None Upper HFC3a C 8-11-03 — 8-11-03 8-11-03 25.1-29.1 — None None Lower HFC3a TV G-3782 8-11-03 — 8-11-03 8-11-03 33.0-34.0 — None None Lower HFC2h TV 3-15-04 3-15-04 3-15-04 3-15-04 15.0-15.8 16.2-17.3 15.0-18.5 16.0-17.2 Lower HFC5e C 3-15-04 3-15-04 3-15-04 3-15-04 46.2-47.0 46.5-47.2 None None Middle HFC2d TV 8-19-03 — — — 9.9-10.5 — — — Lower HFC5e TV 8-19-03 — — — 34.1-34.3 — — — Lower HFC2g3 C G-3783 8-19-03 — — — 34.5-35.5 — — — Lower HFC2g3 C 8-19-03 — — — 38.3-38.6 — — — Lower HFC2f TV 3-15-04 3-11-04 3-11-04 3-11-04 11.5-15.0 12.0-12.1 None 12.5-13.5 Lower HFC4 C? G-3783* 3-15-04 3-11-04 3-11-04 3-11-04 25.5-26.5 25.25-25.35 None None Lower HFC3a C 3-15-04 3-11-04 3-11-04 3-11-04 37.5-40.0 38.0-38.1 None None Lower HFC2f TV G-3784* 9-12-03 — 9-16-03 9-16-03 49.0-49.7 — None None Lower HFC2e1? C Hydrogeologic Framework for Model Representation of the Biscayne Aquifer 1
Table 8. Borehole-flowmeter, fluid-conductivity, and fluid-temperature data for wells that fully penetrate the Biscayne aquifer in the study area and collected over uncased, open-hole intervals. (Continued)
Data collection date Inflection depth (feet below land surface) Local HFC or formation contributing Fluid Fluid Fluid Fluid well Heat-pulse Spinner Heat-pulse Spinner flow into or out Porosity type conduc- temp- conduc- temp- identifier flowmeter flowmeter flometer flowmeter of borehole tivity erature tivity erature 9-11-03 — 9-3-03 9-3-03 8.2-10.5 — None None Lower HFC5e TV 9-11-03 — 9-3-03 9-3-03 18.3-23.2 — None None Lower HFC3a C G-3788* 9-11-03 — 9-3-03 9-3-03 32.4-35.6 — 33.4-34.1 33.8-35.5 Lower HFC2g3 TV 9-11-03 — 9-3-03 9-3-03 38.2-40.2 — None None Lower HFC2f TV 3-10-04 3-10-04 3-10-04 3-10-04 9.0-12.5 8.6-10.1 8.5-10.4 None Lower HFC5e TV 3-10-04 3-10-04 3-10-04 3-10-04 21.4-22.0 20.0-22.3 19.8-22.6 20.5-24.5 Lower HFC3a C G-3788 3-10-04 3-10-04 3-10-04 3-10-04 None 37.8-38.9 None None Lower HFC2f TV 3-10-04 3-10-04 3-10-04 3-10-04 43.0-43.5 None None None Upper HFC2e1? TV 9-12-03 — — — 7.5-10.5 — — — Lower HFC5e TV 9-12-03 — — — 38.6-39.5 — — — Lower HFC2g2 TV 9-12-03 — — — 44.1-46.1 — — — Middle HFC2e2 TV 9-12-03 — — — 49.0-50.0 — — — Lower HFC2e1? TV 3-9-04 3-9-04 3-9-04 3-9-04 9.0-10.0 9.8-9.9 None None Lower HFC5e TV G-3789 3-9-04 3-9-04 3-9-04 3-9-04 11.0-14.0 13.4-13.9 None None Lower HFC4 TV 3-9-04 3-9-04 3-9-04 3-9-04 None 15.6-16.1 None None Middle HFC3b C 3-9-04 3-9-04 3-9-04 3-9-04 None 23.5-24.0 None None Lower HFC3a TV and C? 3-9-04 3-9-04 3-9-04 3-9-04 44.2-46.0 45.3-45.4 None None Middle HFC2e2 TV 3-9-04 3-9-04 3-9-04 3-9-04 46.0-52.5 None None None Lower HFC2e1? TV 3-17-04 3-17-04 3-17-04 3-17-04 6.0-9.0 8.5-10.5 None None Lower HFC5e TV 3-17-04 3-17-04 3-17-04 3-17-04 No data 27.8-29.7 27.8-28.3 None Lower HFC3a TV G-3790 3-17-04 3-17-04 3-17-04 3-17-04 53.0-55.0 53.8-54.8 54.5-56.0 None Lower HFC2e2 TV 3-17-04 3-17-04 3-17-04 3-17-04 58.0-60.0 None None None Lower HFC2d TV 4-6-04 — 4-6-04 4-6-04 9.6-14.6 — 10.0-11.0 None Lower HFC5e TV G-3791 4-6-04 — 4-6-04 4-6-04 45.0-46.3 — None None Lower HFC2f TV 2-26-04 — — — 10.9-14.0 — — — Lower HFC5e TV 2-26-04 — — — 50.2-63.0 — — — Middle HFC2c2 C 2-27-04 — — — 49.5-63.9 — — — Middle HFC2c2 C G-3792 3-18-04 3-18-04 3-18-04 3-18-04 10.9-14.0 None None None Lower HFC5e TV 47.2-47.3 3-18-04 3-18-04 3-18-04 3-18-04 46.0-49.5 None None Lower HFC2d TV 49.4-49.5 3-18-04 3-18-04 3-18-04 3-18-04 50.5-63.0 49.9-66.5 52.8-53.3 53.2-55.0 Middle HFC2c2 C and TV 3-3-04 3-3-04 3-2-04 3-2-04 12.5-14.5 13.45-13.65 None None Lower HFC3a TV 3-3-04 3-3-04 3-2-04 3-2-04 19.5-21.5 20.3-21.05 None None Lower HFC2h TV G-3793* 3-3-04 3-3-04 3-2-04 3-2-04 None 42.2-43.0 None None Lower HFC2d TV 3-3-04 3-3-04 3-2-04 3-2-04 46.4-50.0 45.9-47.6 None None Lower HFC2c2 TV 3-3-04 3-3-04 3-2-04 3-2-04 51.0-53.0 51.8-51.9 51.6-52.3 52.0-55.0 Lower HFC2c2 TV and C? 2-27-04 — — — 16.5-17.5 — — — Lower HFC3a C 2-27-04 — — — 51.8-54.5 — — — Lower HFC2d TV G-3794 3-19-04 3-19-04 3-19-04 3-19-04 16.5-17.5 16.7-17.5 None None Lower HFC3a C 3-19-04 3-19-04 3-19-04 3-19-04 51.8-54.6 50.9-54.3 None None Lower HFC2d TV 3-1-04 — — — 21.8-23.0 — — — Lower HFC3a C 3-1-04 — — — 41.0-47.0 — — — Lower HFC2d TV G-3795 3-1-04 — — — 50.0-55.0 — — — Lower HFC2c2 TV 3-22-04 3-22-04 3-22-04 3-22-04 42.5-49.1 45.3-48.0 None None Lower HFC2d TV 3-22-04 3-22-04 3-22-04 3-22-04 50.0-55.0 50.3-54.9 None None Lower HFC2c2 TV A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
14 UPPER BISCAYNE AQUIFER LOWER BISCAYNE AQUIFER
12 Q5e Q4 Q3 Q2 Q1?
EXPLANATION 10 PREFERENTIAL FLOW ZONE OF REGIONAL EXTENT
PREFERENTIAL FLOW ZONE OF LOCAL EXTENT
8 amiami Formation
T
6
4
NUMBER OF OCCURRENCES
2
0
HFC2d
HFC2e2 HFC2c2
Lower HFC4
Lower HFC2f
Upper HFC3a
Upper HFC2h
Lower HFC3a
Lower HFC2h
Lower HFC5e
Middle HFC3b
Lower HFC2g3
Lower HFC2g2
Lower HFC2e1?
Middle or lower Middle or lower Middle or lower
amiami Formation
Uppermost T VERTICAL POSITION WITHIN HIGH-FREQUENCY CYCLES OF THE BISCAYNE AQUIFER AND UPPERMOST TAMIAMI FORMATION
Figure 32. Number of occurrences of various preferential flow zones in 16 test coreholes fully penetrating the Biscayne aquifer in the study area, verified with heat-pulse or spinner flowmeter measurements, or both. Q units of Perkins (1977) also shown.
Summary and Conclusions conduit porosity composed mainly of bedding‑plane vugs, thin solution pipes, and cavernous vugs. These three conduit A fundamental problem in the simulation of karst ground- porosity types are all pathways for conduit ground-water flow. water flow and solute transport is how to represent aquifer Rock textures, faunal constituents, sedimentary heterogeneity as defined by the spatial distribution of porosity, structures, and relation to surfaces bounding vertical lithofa- permeability, and storage. Combined analyses of lithofacies, cies successions were the basis for defining six principal depositional environments, cyclostratigraphy, and borehole- depositional environments for the Tamiami Formation, Fort geophysical logs as they relate to porosity, permeability, and Thompson Formation, and Miami Limestone, which are storage has improved the representation of the triple-porosity major lithologic components of the Biscayne aquifer. The six karst Biscayne aquifer in an approximately 95-mi2 study area depositional environments are: (1) middle ramp, (2) platform in southeastern Florida. margin-to-outer platform, (3) open-marine platform interior, Karst aquifers are traditionally characterized by three (4) restricted platform interior, (5) brackish platform interior, types of porosity: interparticle matrix porosity, fracture and (6) freshwater terrestrial environments. High-frequency porosity, and large cavernous porosity. This has led many to cycles form the fundamental building blocks of the rocks of view karst aquifers as two component systems, where much the Biscayne aquifer. Vertical lithofacies assemblages, which of the ground-water storage occurs in the matrix porosity or have stacking patterns that reoccur, fit within the high-fre- fractures or both, and much of the ground-water flow and quency cycles. The upward-shallowing subtidal cycle, upward- transport takes place in large dissolutional conduits. In the shallowing paralic cycle, and aggradational subtidal cycle young eogenetic karst that defines the Pleistocene limestone define three types of ideal high-frequency cycles that occur of the Biscayne aquifer, however, a fourth porosity type, within the Fort Thompson Formation and Miami Limestone. touching‑vug porosity, is especially important in terms The key to identification of the upward-shallowing paralic of conveyance of ground water. The triple porosity of the cycle is a capping micrite-rich carbonate lithology indicative Biscayne aquifer is typically: (1) matrix of interparticle of deposition in brackish paralic or freshwater terrestrial envi- and separate-vug porosity, providing much of the storage, ronments. Grouping of high-frequency cycles produced two and under dynamic conditions, diffuse-carbonate flow; cycle sets: one progradational (Fort Thompson Formation) and (2) touching‑vug porosity creating stratiform ground-water another aggradational (Miami Limestone) based on vertical flow pathways formed by touching vugs; and (3) less common cycle patterns. Summary and Conclusions
Spinner flowmeter Fluid ambient temperature March 15, 2004 Computed March 15, 2004 Up at 5 feet per minute Digital borehole 70 (degrees 74 Heat-pulse 0 (counts 15 per second) Lithofacies vuggy Caliper Fahrenheit) image flowmeter Up at 10 feet per minute porosity ambient 0 (counts 15 Geologic unit per second) Fluid March 15, 2004
Hydrogeologic unit Up at 15 feet per minute conductivity 0 (counts 15
High-frequency cycle (HFC) March 15, 2004 per second) 300 500 -1 (gallons +1 Up at 20 feet per minute 0 (PERCENT) 100 0 (INCHES) 20 (microsiemens (counts per minute) 0 15 per centimeter) per second) 7
8
9
10
11 Peloid
ACE packstone and 12 HFC5e grainstone
Miami Limestone 13
14
BELOW LAND SURF
,
Biscayne aquifer 15
IN FEET
16
DEPTH Mudstone? 17 and wackestone?
18 Mudstone and
HFC3b wackestone Inflow 19
of heat-pulse flowmeter
Rate of flow in borehole
downward
Skeletal exceeded resolution limits packstone Fort Thompson Formation and grainstone 20
Figure 33. Comparison of borehole image, computed vuggy porosity, geophysical, and flowmeter logs showing evidence for inflow of ground water from a preferential flow zone into the borehole of the G-3782 test corehole. Most of the inflow seems to occur at a vuggy cavity at the base of HFC5e between the depths of about 15.7 and 16.8 feet below land surface (shaded in pale red).
A primary observation is that a predictable vertical of upward-shallowing subtidal and paralic cycles typically pattern of porosity, permeability, and storage commonly above flooding surfaces within the Fort Thompson Formation exists within the three ideal cycles because these aquifer and an upper aggradational cycle of the Miami Limestone; properties relate directly to lithofacies. Sixteen major touching‑vug ground-water flow is typical for this pore class. lithofacies of the Fort Thompson Formation and Miami Conceptualization of the touching‑vug flow is movement of Limestone have been assigned to one of three pore classes ground water through a stratiform passage formed by coales- (I, II, and III). Pore class I typically comprises the lower part cence of vugs into a mostly tortuous path. Bedding‑plane A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla.
Spinner flowmeter Fluid ambient temperature March 10, 2004 Computed March 10, 2004 Heat-pulse Up at 5 feet per minute Digital borehole 0 (counts 15 Lithofacies vuggy Caliper 77 (degrees 79 flowmeter per second) image Fahrenheit) ambient Up at 10 feet per minute porosity 0 (counts 15 March 10, 2004 per second) Geologic unit Fluid Up at 20 feet per minute Hydrogeologic unit conductivity 0 (counts 15 March 10, 2004 per second)
High-frequency cycle (HFC) Up at 30 feet per minute 0 (PERCENT) 100 0 (INCHES) 20 400 (microsiemens 500 -2 (gallons +2 0 (counts 15 13 per entimeter) per minute) per second) Skeletal grainstone 14 and HFC3b packstone 15 Gastropod floatstone and rudstone Gastropod and 16 skeletal floatstone and rudstone Mudstone and wackestone 17 Pelecypod floatstone and rudstone
ACE Laminated peloid grainstone & packstone 18 Skeletal grainstone 19 and packstone
20 Pelecypod
BELOW LAND SURF
, floatstone
Biscayne aquifer
HFC3a and rudstone 21
Fort Thompson Formation
IN FEET Touching-vug pelecypod 22 floatstone and rudstone
DEPTH 23
24 Planorbella floatstone
Inflow
25 downward
Rate of flow in borehole
of heat-pulse flowmeter
exceeded resolution limits
26
Figure 34. Comparison of borehole image, computed vuggy porosity, geophysical, and flowmeter logs showing evidence for inflow of ground water from two preferential flow zones into the borehole of the G-3788 test corehole. Most of the inflow seems to occur at a bedding-plane vug at about 20 to 20.2 feet below land surface and a cavity that is a combination of touching vugs and a bedding-plane vug at about 21.6 to 22.7 feet below land surface. Both preferential flow zones occur within HFC3a (shaded in pale red). vugs and rare cavernous vugs form conduit porosity that Micrite-dominated lithologies, which may have thin vertical occurs less commonly in pore class I. Pore class II commonly solution pipes (short conduits) and separate vugs, distinguish occurs in the upper part of the upward-shallowing subtidal pore class III. This class commonly caps upward-shallowing cycle and middle part of the upward-shallowing paralic cycles and occurs throughout much of the lower aggradational cycle. This class is principally interparticle and separate-vug cycle of the Miami Limestone. These micrite-rich lithologies porosity, and is characterized by diffuse-carbonate ground- leak vertically, but tend to inhibit horizontal ground-water water flow through vug‑to-matrix-to-vug connections. movement. Summary and Conclusions
Fluid Spinner temperature flowmeter Computed March 2, 2004 Heat-pulse ambient Digital borehole Lithofacies vuggy Caliper 78 (degrees 82 flowmeter March 3, 2004 image Fahrenheit) ambient Down at 7 feet porosity per minute March 3, 2004
Geologic unit Fluid 0 (counts 10 per second) Hydrogeologic unit conductivity Down at 26 feet March 2, 2004 per minute
High-frequency cycle (HFC) 0 (PERCENT) 100 0 (INCHES) 20 700 (microsiemens 900 -1.5 (gallons +1.5 0 (counts 10 per centimeter) per minute) per second) 43
44 Sandy skeletal 45 packstone
46
Inflow upward
47
ACE Sandy 48 pelecypod
HFC2c2 rudstone
49
Very sandy 50 touching-
BELOW LAND SURF
, vug
Biscayne aquifer pelecypod 51 rudstone Fort Thompson Formation Cavity with
IN FEET semivertical 52 root casts and intercast vugs
DEPTH Sandy 53 skeletal packstone
Sandy 54 pelecypod floatstone
HFC2b 55 and rudstone
56
Figure 35. Comparison of borehole image, computed vuggy porosity, geophysical, and flowmeter logs showing evidence for inflow of ground water from a preferential flow zone into the borehole of the G-3793 test corehole. Most of the inflow seems to occur at a vuggy cavity at the base of HFC2c2 between the depths of about 51.1 and 52.7 feet below land surface (shaded in pale red).
It is proposed that the karstic development of the highly tively low-permeability lithologies at cycle tops that underlie permeable zones at the base of upward-shallowing cycles of flooding surfaces and act as baffles or barriers to downward the Fort Thompson Formation relates to cyclostratigraphy vertical drainage. and Pleistocene sea-level history. Formation of secondary The cyclostratigraphic approach taken herein demon- porosity was probably produced by meteoric water flowing strates that its combined use with borehole-geophysical logs through the limestone of the Fort Thompson Formation during is valuable to the development of an accurate conceptual its emergence into the vadose zone, caused by periodic low three-dimensional hydrogeologic model. The one-dimensional stands in sea level that span Pleistocene glacial maximums. cyclostratigraphic framework, or fingerprint, of each well The focused, low-gradient lateral flow of meteoric water above used in the conceptual model permitted correlation of vertical flooding surfaces is postulated due to the presence of rela- lithofacies successions and high-frequency cycles and the A Cyclostratigraphic and Borehole-Geophysical Approach to Development of a Hydrogeologic Model, SE Fla. well-to-well connection of corresponding highly porous and Cunningham, K.J., Carlson, J.L., Wingard, G.L., and others, 2004b, permeable zones between wells. The concepts should be Characterization of aquifer heterogeneity using cyclostratigraphy useful in providing a framework for numerical simulations of and geophysical methods in the upper part of the karstic Biscayne regional-scale dual- and triple-porosity ground-water flow and aquifer, southeastern Florida: U.S. Geological Survey Water- solute transport. Many karst aquifers occur in cyclic platform Resources Investigation Report 03-4208, 46 p., 5 pls. carbonates, so the cyclostratigraphic approach is applicable to Cunningham, K.J., Renken, R.A., Wacker, M.A., and others, 2006 numerous areas of the world. Applications include wellhead (in press), Application of carbonate sequence stratigraphy to delin- protection at well fields, design of tracer studies, solute-trans- eate porosity, preferential flow, and advective transport in the karst port modeling of contaminants, saltwater intrusion modeling limestone of the Biscayne aquifer, SE Florida, USA, in Harmon, and monitoring in coastal areas, engineering design of under- R.S., and Wicks, Carol, eds., Perspectives on Karst Geomorphol- ground barriers to seepage and tunnels, delineation of storage ogy, Hydrology and Geochemistry—A Tribute Volume to Derek C. zones for aquifer storage and recovery projects, and simulation Ford and William B. White: Geological Society of America, Special of regional-scale karst ground-water flow. Paper 404. 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