DOCSLIB.ORG

Virginia, Maryland, and West Virginia

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Virginia, Maryland, and West Virginia Geology of the Harpers Ferry Quadrangle, Virginia, Maryland, and West Virginia a, tr ' .a\ p 94Z3 i E - As { i 7 r Auff Preparedin cooperation with the Maryland Geological Survey, oo the NationalPark Service, and the Loudoun County Departmentof EnvironmentalResources x- J metadc958060 U.S. GEOLOGICAL SURVEY BULLETIN 2123 Cover: Looking %vestat Harpers Ferry. Wes Virginia, hrom the Loudoun Heights trail on Blue Ridge in Virginia. Photograph taken March 1989 by Scott Southworth. Geology of the Harpers Ferry Quadrangle, Virginia, Maryland, and West Virginia By Scott Southworth and David K. Brezinski U.S. GEOLOGICAL SURVEY BULLETIN 2123 m , Preparedin cooperation with the Maryland Geological Survey, the National Park Service, and the Loudoun County Departmentof Environmental Resources - H 3 Structure and stratigraphyof the Middle Proterozoic through Early Cambrian rocks of the complexly deformed Late Paleozoic Blue Ridge-South Mountain anticlinorium UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1996 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY GORDON P. EATON, Director For sale by U.S. Geological Survey, Information Services Box 25286, Federal Center, Denver, CO 80225 Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Published in the Eastern Region, Reston, Va. Manuscript approved for publication January 9, 1995. Library of Congress Cataloging in Publication Data Southworth, Scott, 1957- Geology of the Harpers Ferry Quadrangle, Virginia, Maryland, and West Virginia / by Scott Southworth and David K. Brezinski. p. cm. - (U.S. Geological Survey bulletin : 2123) "Prepared in cooperation with the Maryland Geological Survey, the National Park Service, and the Loudoun County Department of Environmental Resources." "Structure and stratigraphy of the Middle Proterozoic through Early Cambrian rocks of the complexly deformed Late Paleozoic Blue Ridge-South Mountain anticlinorium." Includes bibliographical references (p. - ). Supt. of Docs. no.: 119.3:2123 . Geology-West Virginia-Harper's Ferry Region. 2. Geology, Stratigraphic. I. Brezinski, David K. II. Maryland Geological Survey. III. Loudoun County (Va.). Dept of Environmental Resources. IV. Title. V. Series. QE75.B9 no. 2123 [QE 178] 557.3 s-dc 2095-9727 [557.54'99] CIP CONTENTS A bs track t ........................................................................................................................... I Introduction and Geologic Setting............................................................................... Middle Proterozoic Rocks .............................................................................................. 3 Garnet Graphite Gneiss ........................................................................................... 3 Ho rnb lend e G neiss ................................................................................................ 4 Garnet Monzogranite...........................................4 B io tite G neiss ....................................................................................................... 5 L ate P ro terozo ic R o ck s .................................................................................................. 7 S w ift Ru n Fo rm atio n ............................................................................................... 7 M e tad iab ase D ikes............................................................................................... ... 7 M etarhyolite D ikes................................................................................................ 8 Catoctin Fo rm atio n ................................................................................................. 10 Paleo zo ic R o ck s . ............................................................................................................. 10 C hilho w ee G roup ................................................................................................... 10 Loudoun Fo rm ation....................................................................................... 10 P h yllite ..................................................... .............................................. 1 1 Conglomerate......................................... 12 W everton Fo rmation....................................................................................... 12 Buzzard Knob Member..........................................................................13 Maryland Heights Member...............................13 Owens Creek M ember........................................................................... 13 H arp ers F ormation.......................................................................................... 1 3 Antietam Formation ........................................................................................ 14 Tomstown Formation.............................................................................................. 14 Bolivar Heights Member..................................... 15 Fort Duncan M ember.....................................................................................15 B enevola M em b er .......................................................................................... 15 Jurassic Diabase D ik es .................................................................................................... 15 M etamo rphism . ............................................................................................................... 1 6 Structural Geology................................................ 16 Gneissic Foliation .............................................. Mylonitic and Phyllonitic Foliation ........................................................................ 17 B e dd in g . .................................................................................................................. 1 7 Cleavage.................................................................................................................. 17 Middle Proterozoic Rocks...............................................................................17 Late Proterozoic and Lower Cambrian Rocks ............................................... 17 Late Proterozoic Dikes....................................................................................19 Crenulation Cleavage.......................................... 19 Shear Band Cleavage........................................... 19 Lineations............................................................19 Jo in ts ....................................................................................................................... 19 Folds.........................................................................................................................19 Fau lts . ...................................................................................................................... 2 2 T ecto nic H isto ry ...................................................................................................... .. 25 M idd le Pro terozo ic ................................................................................................ 25 Late Proterozoic......... ...... ................................................................. 26 Paleozoic ................................................................................................................. 26 III IV CONTENTS Mesozoic ................................................................................................................. 29 Cenozoic ................................................................................................................. 29 Q uaternary Bedrock Landslides..................................................................................... 29 Surficial Geology ............................................................................................................ 29 Acknowledgments .......................................................................................................... 29 References Cited ............................................................................................................. 30 PLATE [Plate is in pocket] 1. Geologic map of the Harpers Ferry quadrangle, Virginia, Maryland, and West Virginia. FIGURES 1. Index map showing the location of the Harpers Ferry quadrangle and adjacent quadrangles within the Blue Ridge-South Mountain anticlinorium, and type localities of the members of the Weverton and T o m stow n F orm ations .............................................................................................................................................. 2 2. Quartz-alkali feldspar-plagioclase feldspar diagram showing modal compositions of Middle Proterozoic rocks, and normative feldspar plot of Middle Proterozoic rocks in the Harpers Ferry quadrangle......................... 3 3. Index map showing the locations of isotopically dated rock units discussed in text.............................................. 6 4. Photograph showing garnet monzogranite and gneissic foliation defining Grenvillian folds................................ 7 5. Photograph showing sericitic quartzite of the Swift Run Formation showing beds interpreted to be overturned and cut by cleavage, and closeup showing cobbles and pebbles of siltstone and iron-rich sandstone.................... 8 6. Hf/3-Th-Ta ternary diagram for tectonic setting of Late Proterozoic metadiabase dikes, extrusive metabasalt,
Load more

Recommended publications
  • Nomination Form, 1983]
    NPS Form 10-900 0MB No. 1024-0018 (Rev. Aug. 2002) VvvL ~Jtf;/~ United States Department of the Interior National Park Service !VfH-f G"/;<-f/q NATIONAL REGISTER OF HISTORIC PLACES REGISTRATION FORM This form is for use in nominating or requesting determinations for individual properties and districts. See instructions in How to Complete the National Register of Historic Places Registration Form (National Register Bulletin 16A). Complete each item by marking "x" in the appropriate box or by entering the information requested. If any item does not apply to the property being documented, enter "N/A" for "not applicable." For functions, architectural classification, materials, and areas of significance, enter only categories and subcategories from the instructions. Place additional entries and narrative items on continuation sheets (NPS Form 10-900a). Use a typewriter, word processor, or computer, to complete all items. ============================================================================================== 1. Name of Property ============================================================================================== historic name Bear's Den Rural Historic District other names/site number VDHR File No. 021-6010 ============================================================================================== 2. Location ============================================================================================== street & number Generally runs along both sides of ridge along parts of Raven Rocks and Blue Ridge Mtn Rds, extends down Harry
    [Show full text]
  • Loudoun County African-American Historic Architectural Resources Survey
    Loudoun County African-American Historic Architectural Resources Survey Lincoln "Colored" School, 1938. From the Library of Virginia: School Building Services Photograph Collection. Prepared by: History Matters, LLC Washington, DC September 2004 Sponsored by the Loudoun County Board of Supervisors & The Black History Committee of the Friends of the Thomas Balch Library Leesburg, VA Loudoun County African-American Historic Architectural Resources Survey Prepared by: Kathryn Gettings Smith Edna Johnston Megan Glynn History Matters, LLC Washington, DC September 2004 Sponsored by the Loudoun County Board of Supervisors & The Black History Committee of the Friends of the Thomas Balch Library Leesburg, VA Loudoun County Department of Planning 1 Harrison Street, S.E., 3rd Floor Leesburg, VA 20175 703-777-0246 Table of Contents I. Abstract 4 II. Acknowledgements 5 III. List of Figures 6 IV. Project Description and Research Design 8 V. Historic Context A. Historic Overview 10 B. Discussion of Surveyed Resources 19 VI. Survey Findings 56 VII. Recommendations 58 VIII. Bibliography 62 IX. Appendices A. Indices of Surveyed Resources 72 B. Brief Histories of Surveyed Towns, Villages, Hamlets, 108 & Neighborhoods C. African-American Cemeteries in Loudoun County 126 D. Explanations of Historic Themes 127 E. Possible Sites For Future Survey 130 F. Previously Documented Resources with Significance to 136 Loudoun County’s African-American History 1 Figure 1: Map of Loudoun County, Virginia with principal roads, towns, and waterways. Map courtesy of the Loudoun County Office of Mapping. 2 Figure 2. Historically African-American Communities of Loudoun County, Virginia. Prepared by Loudoun County Office of Mapping, May 15, 2001 (Map #2001-015) from data collected by the Black History Committee of the Friends of Thomas Balch Library, Leesburg, Va.
    [Show full text]
  • GEOLOGIC SUMMARY of the APPALACHIAN BASIN, with REFERENCE to the SUBSURFACE DISPOSAL of RADIOACTIVE WASTE SOLUTIONS by George W
    TEI-791 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY" GEOLOGIC SUMMARY OF THE APPALACHIAN BASIN, WITH;REFERENCE TO THE SUBSURFACE DISPOSAL OF RADIOACTIVE WASTE SOLUTIONS* By George W. Colton June 1961 Report TEI-791 This report is preliminary and ha^;not been edited for conformity with G^logical Survey format and nomenclature. ?1 ^Prepared on behalf of the U. S. Atomic Energy Commission. CONTENTS Abstract* .......................... 5 Introduction. ........................ 7 Purpose of report. ................... 7 Organization of report .................. 7 Location and extent of area. .............. Q Acknowledgments. .................... 10 Geologic framework. ..................... 10 Depositional framework ................. 10 Structural framework .................. llj. Stratigraphy. ........................ 17 Late Precambrian stratified sequence .......... 17 Early Cambrian clastic sequence. ............ 18 Thickness and depth ................ 22 Cambrian-Ordovician carbonate sequence ......... 23 Thickness and depth . , ........... 35 Late Ordovician clastic sequence ............ 35 Thickness and depth ................ Mi- Early Silurian clastic sequence. ............ kk Thickness and depth ................ 51 Silurian-Devonian carbonate sequence .......... 52 Thickness and depth ................ 62 Devonian classic sequence. ............... 63 Thickness and depth ................ 69 Mississippian sequence ................. 70 Thickness and depth ................ 79 Pennsylvanian sequence ................. 79 Waste
    [Show full text]
  • The Geology of the Tama Kosi and Rolwaling Valley Region, East-Central Nepal
    The geology of the Tama Kosi and Rolwaling valley region, East-Central Nepal Kyle P. Larson* Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada ABSTRACT Tama Kosi valley in east-central Nepal (Fig. 1). which were in turn assigned to either the Hima- In order to properly evaluate the evolution of the layan gneiss group or the Midlands metasedi- The Tama Kosi/Rolwaling area of east- Himalaya and understand the processes respon- ment group (Fig. 2). The units of Ishida (1969) central Nepal is underlain by the exhumed sible for its formation, it is critical that all areas and Ishida and Ohta (1973) are quite similar in mid-crustal core of the Himalaya. The geol- along the length of the mountain chain be inves- description to the tectonostratigraphy reported ogy of the area consists of Greater Hima- tigated, at least at a reconnaissance scale. by Schelling (1992) who revisited and expanded layan sequence phyllitic schist, paragneiss, The Tama Kosi valley is situated between the the scope of their early reconnaissance work. and orthogneiss that generally increase in Cho Oyu/Everest/Makalu massifs to the east Schelling (1992) separated the geology of metamorphic grade from biotite ± garnet and the Kathmandu klippe/nappe to the west the lower and middle portion of the Tama Kosi assemblages to sillimanite-grade migmatite (Fig. 1). Recent work in these areas serves to into the more traditional Greater Himalayan up structural section. All metamorphic rocks highlight stark differences between them. In the sequence (Higher Himalayan Crystallines) and are pervasively deformed and commonly Kathmandu region, the extruded midcrustal core Lesser Himalayan sequence lithotectonic assem- record top-to-the-south sense shear.
    [Show full text]
  • Lexington Quadrangle Virginia
    COMMONWEALTH OF VIRGINIA DEPARTMENT OF CONSERVATION AND ECONOMIC DEVELOPMENT DIVISION OF MINERAL RESOURCES GEOLOGY OF THE LEXINGTON QUADRANGLE VIRGINIA KENNETH F. BICK REPORT OF INVESTIGATIONS I VIRGINIA DIVISION OF MINERAL RESOURCES Jomes L. Colver Commissioner of Minerol Resources ond Stote Geologist CHARLOTTESVI LLE, VI RGI N IA 1960 COMMONWEALTH OF VIRGINIA DEPARTMENT OF CONSERVATION AND ECONOMIC DEVELOPMENT DIVISION OF MINERAL RESOURCES GEOLOGY OF THE LEXINGTON QUADRANGLE VIRGINIA KENNETH F. BICK REPORT OF INVESTIGATIONS I VIRGINIA DIVISION OF MINERAL RESOURCES Jomes L. Colver Commissioner of Minerol Resources ond Stote Geologist CHARLOTTESVI LLE, VI RGI N IA 1960 Couuowwoer,rn op Vtncrwre DopenrupNr op Puncnesrs exo Supptv Rrculroxn 1960 DEPARTMENT OF CONSERVATION AND ECONOMIC DEVELOPMENT Richmond. Virginia MenvrN M. SurHnnr,eNn, Director BOARD Vrcron W. Stnwenr, Petersburg, Chairtnan G. Ar,vrn MessnNnunc, Hampton, Viee'Chairman A. Pr,urvrnr BmnNn, Orange C. S. Cenrnn, Bristol ANpnpw A. Fenr,pv, Danville WonrnrrvcroN FauLKNEn, Glasgow SvoNpv F. Slter,r,, Roanoke EnwrN H. Wrr,r,, Richmond Wrr,r,renr P. Wooor,nv. Norfolk CONTENTS Pece Abstract. '"*i"#:;;;;: . : ::: , : ::.:::::::::..::::::. :.::.::::::: ::,r Z Geography 8 Purpose. 4 Previous Work. Present Work and Acknowledgements. 5 Geologic Formations. 6 Introduction. 6 Precambrian System. 6 Pedlar formation 6 Precambrian and Cambrian Systems. 6 Discussion. 6 Swift Run formation 8 Catoctin greenstone. I Unieoiformation...... ......... I Hampton(Harpers)formation. .......... I Erwin (Antietam) quartzite. Cambrian System . I0 Shady (Tomstown) dolomite 10 Rome (Waynesboro) formation.... ll Elbrook formation. 12 Conococheague limestone. l3 Ordovician System. ......., 14 Chepultepeclimestone. .......... 14 Beekmantown formatron. 14 New Market limestone. 15 Lincolnshire limestone. 16 Edinburg formation. 16 Martinsburg shale... 17 SilurianSystem. ......... 18 Clinchsandstone..... .......... 18 Clinton formation.
    [Show full text]
  • PALEOZOIC STRATIGRAPHIC COLUMN of Central Pennsylvania
    PALEOZOIC STRATIGRAPHIC COLUMN of Central Pennsylvania _____________________________________________________________________*Ridge Makers System & Series Formation and Members General Description Llewellyn Formation Cycles of conglomerate or sandstone; underclay coal, shale Pnn. L & N 2000’+ Pottsville Formation* Cycles of conglomerate or sandstone; underclay coal, shale L & M 1400’ Mauch Chunk Grayish red and gray shale M 5000’ Miss. Pocono* Mount Carbon Gray to buff, medium grained, cross-bedded sandstone 1600’ 940’ Beckville Gray to buff, medium grained, cross-bedded sandstone Lower 225’ Spechty Kopf Gray, fine and medium grained sandstone conglomerate 435’ near middle and base Catskill Duncannon Asymmetric, upward-fining fluvial cycles, basal nonred, locally 7250’ 2000’ conglomeratic sandstone is overlain by grayish red sandstone and siltstones Sherman Creek Interbedded grayish red claystone and fine grained, cross- 2400’ bedded sandstone Upper Irish Valley Interbedded, grayish red and olive gray sandstone, siltstone, 2850’ shale, overlain upward-fining cyclic deposits of gray sandstone and red siltstone Trimmers Rock Medium gray siltstone and shale, with fine grained sandstone in 2000’ upper part; graded bedding common Harrell Olive and medium light gray shale 200’ Mahantango Sherman Ridge* Olive gray, fossiliferous, claystone with interbedded fine 1600’ 600’ sandstones which coarsen upward Montebello Olive gray, medium grained, locally conglomeratic, fossiliferous 600’ sandstone, interbedded with siltstone and claystone in upward-
    [Show full text]
  • Metamorphic Rocks.Pdf
    Metamorphism & Metamorphic Rocks (((adapted from Brunkel, 2012) Metamorphic Rocks . Changed rocks- with heat and pressure . But not melted . Change in the solid state . Textural changes (always) . Mineralogy changes (usually) Metamorphism . The mineral changes that transform a parent rock to into a new metamorphic rock by exposure to heat, stress, and fluids unlike those in which the parent rock formed. granite gneiss Geothermal gradient Types of Metamorphism . Contact metamorphism – – Happens in wall rock next to intrusions – HEAT is main metamorphic agent . Contact metamorphism Contact Metamorphism . Local- Usually a zone only a few meters wide . Heat from plutons intruded into “cooler” country rock . Usually forms nonfoliated rocks Types of Metamorphism . Hydrothermal metamorphism – – Happens along fracture conduits – HOT FLUIDS are main metamorphic agent Types of Metamorphism . Regional metamorphism – – Happens during mountain building – Most significant type – STRESS associated with plate convergence & – HEAT associated with burial (geothermal gradient) are main metamorphic agents . Contact metamorphism . Hydrothermal metamorphism . Regional metamorphism . Wide range of pressure and temperature conditions across a large area regional hot springs hydrothermal contact . Regional metamorphism Other types of Metamorphism . Burial . Fault zones . Impact metamorphism Tektites Metamorphism and Plate Tectonics . Fault zone metamorphism . Mélange- chaotic mixture of materials that have been crumpled together Stress (pressure) . From burial
    [Show full text]
  • Geologic Map of the Loudoun County, Virginia, Part of the Harpers Ferry Quadrangle
    U.S. DEPARTMENT OF THE INTERIOR TO ACCOMPANY MAP MF-2173 U.S. GEOLOGICAL SURVEY GEOLOGIC MAP OF THE LOUDOUN COUNTY, VIRGINIA, PART OF THE HARPERS FERRY QUADRANGLE By C. Scott Southworth INTRODUCTION Antietam Quartzite constituted the Chilhowee Group of Early Cambrian age. Bedrock and surficial deposits were mapped in 1989-90 as part For this report, the Loudoun Formation is not recognized. As of a cooperative agreement with the Loudoun County Department used by Nickelsen (1956), the Loudoun consisted primarily of of Environmental Resources. This map is one of a series of geologic phyllite and a local uppermost coarse pebble conglomerate. Phyl- field investigations (Southworth, 1990; Jacobson and others, lite, of probable tuffaceous origin, is largely indistinguishable in the 1990) in Loudoun County, Va. This report, which includes Swift Run, Catoctin, and Loudoun Formations. Phyl'ite, previously geochemical and structural data, provides a framework for future mapped as Loudoun Formation, cannot be reliably separated from derivative studies such as soil and ground-water analyses, which phyllite in the Catoctin; thus it is here mapped as Catoctin are important because of the increasing demand for water and Formation. The coarse pebble conglomerate previously included in because of potential contamination problems resulting from the the Loudoun is here mapped as a basal unit of the overlying lower recent change in land use from rural-agricultural to high-density member of the Weverton Formation. The contact of the conglom­ suburban development. erate and the phyllite is sharp and is interpreted to represent a Mapping was done on 5-ft-contour interval topographic maps major change in depositional environment.
    [Show full text]
  • Dec 15, 1999 LAB MANUAL 1209
    October 2012 LAB MANUAL 1209.0 1209.0 LITHOLOGICAL SUMMARY 1209.1 GENERAL This test procedure is performed on aggregates to determine the per- centage of various rock types (especially the deleterious varieties) regulated in the Standard Specifications for Construction. 1209.2 APPARATUS A. Dilute Hydrochloric Acid (10% ±) - One part concentrated HCL with 9 parts water and eyedropper applicator B. "Brass Pencil" - (See Section 1218.2 for description) C. Balances - Shall conform to AASHTO M 231 (Classes G2 & G5). Readability & sensitivity 0.1 grams, accuracy 0.1 grams or 0.1%. Balances shall be appropriate for the specific use. D. Small Hammer, Steel Plate and Safety Glasses E. Paper Containers - Approximately 75mm (3") in diameter F. Magnifying Hand Lens (10 to 15 power) G. Unglazed Porcelain Tile (streak plate) 1209.3 TEST SAMPLE The test sample, prepared in accordance with Section 1201.4G, shall be washed (Observe washing restrictions in Section 1201.4G1c) and then dried to a constant weight at a temperature of 110 ± 5 °C (230 ± 9 °F). (See Section 1201, Table 1, for sample weights.) 1209.4 PROCEDURE Examine and classify each rock piece individually. Some rock types may need to be cracked open to identify or determine the identifying properties of the rock. (Always wear safety glasses). The following general guidelines are for informational purposes: • Always break open pieces of soft rock or any others of which you are unsure as the outside is often weathered. • Pick the easy particles first October 2012 LAB MANUAL 1209.4 • Don't be overly concerned about questionable particles unless they will fail the sample.
    [Show full text]
  • Propane Costs Too Much!
    STANDARD PRESORT RESIDENTIAL U.S. POSTAGE CUSTOMER PAID ECRWSS PERMIT NO. 82 WOODSTOCK, VA FEBRUARY 2019 www.blueridgeleader.com blueridgeleader SINCE 1984 ‘Personal Recreation Fields’ free to turn rural Loudoun into dumping grounds BY ANDREA GAINES In an impassioned letter dated Jan. 24, 2019, Cattail, LC, a limited partnership of family members who have over 800 acres of farmland under Nature Conservancy easement outside of Hamilton, showed the Board of Supervisors the necessity of dealing with an almost wholly unregulated landfill approved by the County. The letter was accompanied by a stun- ningly raw video showing what can only be described as massive landfill activity, “mas- Loudoun, show your querading,” says the partnership, as what is known as a “Personal Recreational Field.” love for Cannons That field is, in fact, an 18-acre tract of land – 30 feet high in some places – and strewn Aerial photos, video, and an explanation baseball; Team seeks of the case can be seen at www. with piles of dirt, massive chunks of con- LoudounRuralLandFills.com. host families crete and asphalt, construction debris, plas- For a copy of the Cattail, LC “Open Letter tic waste, and, in some places, liquid waste. to The Board of Supervisors, Jan. 24, BY ANDREA GAINES The waste is brought in by large dump 2019,” go to BlueRidgeLeader.com. The opening of the baseball season trucks accessing the site from old Business is some months away, but the Can- nons organization is working hard 7. The trucks enter – dozens and dozens per required to dispose of in a particular manner.
    [Show full text]
  • Catoctin Formation
    Glimpses of the Past: THE GEOLOGY of VIRGINIA The Catoctin Formation — Virginia is for Lavas Alex Johnson and Chuck Bailey, Department of Geology, College of William & Mary Stony Man is a high peak in Virginia’s Blue Ridge Mountains that tops out at just over 1200 m (4,000’). Drive south from Thornton Gap along the Skyline Drive and you’ll see the impressive cliffs of Stony Man’s northwestern face. These are the cliffs that give the mountain its name, as the cliffs and slopes have a vague resemblance to a reclining man’s forehead, eye, nose, and beard. Climb to the top and you’ll see peculiar bluish-green rocks exposed on the summit that are ancient lava flows, part of a geologic unit known as the Catoctin Formation. From the presidential retreat at Camp David to Jefferson’s Monticello, from Harpers Ferry to Humpback Rocks, the Catoctin Formation underlies much of the Blue Ridge. This distinctive geologic unit tells us much about the long geologic history of the Blue Ridge and central Appalachians. Stony Man’s summit and northwestern slope, Shenandoah National Park, Virginia. Cliffs expose metabasaltic greenstone of the Neoproterozoic Catoctin Formation. (CMB photo). Geologic cross section of Stony Man summit area (modified from Badger, 1999). The Catoctin Formation was first named by Arthur Keith in 1894 and takes its name for exposures on Catoctin Mountain, a long ridge that stretches from Maryland into northern Virginia. The word Catoctin is rooted in the old Algonquin term Kittockton. The exact meaning of the term has become a point of contention; among historians the translation “speckled mountain” is preferred, however local tradition holds that that Catoctin means “place of many deer” (Kenny, 1984).
    [Show full text]
  • Stratigraphy, Structure, and Tectonics: an East-To-West Transect of the Blue Ridge and Valley and Ridge Provinces of Northern Virginia and West Virginia
    FLD016-05 2nd pgs page 103 The Geological Society of America Field Guide 16 2010 Stratigraphy, structure, and tectonics: An east-to-west transect of the Blue Ridge and Valley and Ridge provinces of northern Virginia and West Virginia Lynn S. Fichter Steven J. Whitmeyer Department of Geology and Environmental Science, James Madison University, 800 S. Main Street, Harrisonburg, Virginia 22807, USA Christopher M. Bailey Department of Geology, College of William & Mary, Williamsburg, Virginia, USA William Burton U.S. Geological Survey, Reston, Virginia 22092, USA ABSTRACT This fi eld guide covers a two-day east-to-west transect of the Blue Ridge and Valley and Ridge provinces of northwestern Virginia and eastern West Virginia, in the context of an integrated approach to teaching stratigraphy, structural analysis, and regional tectonics. Holistic, systems-based approaches to these topics incorpo- rate both deductive (stratigraphic, structural, and tectonic theoretical models) and inductive (fi eld observations and data collection) perspectives. Discussions of these pedagogic approaches are integral to this fi eld trip. Day 1 of the fi eld trip focuses on Mesoproterozoic granitoid basement (associated with the Grenville orogeny) and overlying Neoproterozoic to Early Cambrian cover rocks (Iapetan rifting) of the greater Blue Ridge province. These units collectively form a basement-cored anticlinorium that was thrust over Paleozoic strata of the Val- ley and Ridge province during Alleghanian contractional tectonics. Day 2 traverses a foreland thrust belt that consists of Cambrian to Ordovician carbonates (Iapetan divergent continental margin), Middle to Upper Ordovician immature clastics (asso- ciated with the Taconic orogeny), Silurian to Lower Devonian quartz arenites and car- bonates (inter-orogenic tectonic calm), and Upper Devonian to Lower Mississippian clastic rocks (associated with the Acadian orogeny).
    [Show full text]