(Carboniferous) Systems in the United States— Virginia

By KENNETH J. ENGLUND

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1110-C

Prepared in cooperation with the
Virginia Division of Mineral
Resources

Historical review and summary of areal, stratigraphic,
structural, and economic geology of Mississippian
and Pennsylvanian rocks in southwestern Virginia

[graphic]

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1979

CONTENTS

Page

Abstract CI

Introduction .. 1

Early investigations 1

Present investigations 2

Geologic setting 3

Contact relations with underlying rocks 3

Contact relations with overlying rocks 3

Structural events during deposition, 3

Structural events following deposition 4

Stratigraphy 4

Mississippian System 4

Big Stone Gap Member of the Chattanooga Shale 4

Price Formation 5

Maccrady Shale 8

Greenbrier Limestone 8

Bluefield Formation 10

Hinton Formation 10

Princeton Sandstone 11

Mississippian and Pennsylvanian Systems 11

Blue stone Formation 11

Lee Formation 14

Pennsylvanian System 15

Pocahontas Formation 15

New River Formation 15

Norton Formation 16

Gladeville Sandstone 16

Wise Formation 16

Harlan Formation 16

Mississippian-Pennsylvanian boundary 16

Facies changes 17

Depositional environments 17

Igneous rocks . 18

Economic resources 18

Coal 18

Natural gas and petroleum 19

Limestone 19

Acknowledgments 19

References cited 19

ILLUSTRATIONS

P»sre

Figure 1. Map showing outcrop of the Mississippian and Pennsylvanian Systems in Virginia C2

2. Index map of the southwestern Virginia coal field 5

3. Stratigraphic nomenclature used in southwestern Virginia 6

4. Stratigraphic cross section showing the relation of formations to the Mississippian-Pennsylvanian systemic

boundary between the Cumberland Gap and Bramwell areas of the southwestern Virginia coal field 12

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THE MISSISSIPPIAN AND PENNSYLVANIAN (CARBONIFEROUS) SYSTEMS

IN THE UNITED STATES—VIRGINIA

Ry Kenneth J. Englund

ABSTRACT

Carboniferous rocks in Virginia range from Early Mississippian to Middle Pennsylvanian in age and consist mostly of interbedded sandstone, siltstone, ahale, limestone, claystone, and coal. These aedimentary deposits are assigned to 15 formations, which underlie areas that total approximately 7,000 km3 in the Appalachian Plateaus and the Valley and Ridge physiographic provinces in the southwestern part of the State.

The sedimentation patterns and fossil content of the rock sequence have recorded fluctuations between marine and continental depositional environments in the east-central part of the Appalachian basin. In Mississippian time, marine events predominated during the deposition of a southeastward-thickening sequence of mostly limestone, shale, and siltstone, which, to the east, includes lobes of barrier-bar and terrestrial coal-bearing sediments. A repetition of marine and terrestrial environments prevailed until Early Pennsylvanian time, when a major seaward progradation of deltaic coal-bearing sediments took place. Deposition was continuous across the systemic boundary in the trough area or eastern part of the Appalachian basin, whereas on the western limb of the basin, including westernmost Virginia, Upper Mississippian and Lower Pennsylvanian rocks were eroded sufficiently to form a hiatus between the Mississippian and Pennsylvanian Systems. The deposition of terrestrial coalbearing sediments continued throughout Early and Middle Pennsylvanian time with only an occasional marine transgression. Carboniferous rocks were folded and faulted by thrusting from the southeast during late or post-Paleozoic deformation. Consequently, strata in the Appalachian Plateaus were gently folded and, in the Cumberland overthrust aheet, thrust about 6.4 km to the northwest. At the southeastern edge o' the plateaus and in the Valley and Ridge province, Cai boniferous strata were highly folded and faulted.

Coal, natural gas, and limestone are the principal mineral resources of economic interest in the Carboniferous rocks of Virginia. Coal of high-volatile A to low-volatile bituminous rank is the principal developed mineral resource.

INTRODUCTION

The Mississippian and Pennsylvanian Systems in Virginia are represented by approximately 5,100 m of sedimentary rocks consisting of intercalated

sandstone, siltstone, shale, claystone, limestone, and coal. The distribution of the rocks representing these systems is limited to the western part of the State, principally to the Appalachian Plateaus, and, to a lesser extent, to isolated areas of the adjoining Valley and Ridge province (fig. 1). Within the Appalachian Plateaus, strata are relatively flat and, except for sharply upturned beds near the southeastern edge, show only slight to moderate structural deformation. In contrast, correlative rocks of the Valley and Ridge province are found in several discontinuous and highly deformed fault slices that strike northeast across the west-central part of the State. Rocks of Mississippian age are the most widely distributed and include: (1) subsurface beds beneath Pennsylvanian rocks of the Appalachian Plateaus, (2) upturned beds at the southeastern edge of the plateaus, and (3) sporadic occurrences in the faulted and folded belt of the Valley and Ridge province. These rocks are largely of marine origin, but locally they grade into, and include, nearshore and terrestial deposits. Pennsylvanian rocks consist mostly of terrestial coal-bearing deposits that underlie the Appalachian Plateaus in the east-central part of the broad Appalachian coal basin and a few outliers in the faulted and folded belt. The latter areas are too small to show at the map scale.

The stratigraphic nomenclature used in this paper has not been reviewed by the Geologic Names Committee of the U.S. Geological Survey. The nomenclature used here conforms with the current usage of the Virginia Division of Mineral Resources.

EARLY INVESTIGATIONS

Early investigations of the Mississippian and Pennsylvanian rocks of Virginia were made by Lesley (1873), Stevenson (1881), Rogers (in MacFarlane, 1879), Boyd (1887), and McCreath and d'Invilliers (1888). These studies furnished pre

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