U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2012–3075

June 2012

National Assessment of Oil and Gas

Assessment of Undiscovered Oil and Gas Resources of the East Coast 

Mesozoic Basins of the Piedmont, Blue Ridge Thrust Belt, Atlantic 

Coastal Plain, and New England Provinces, 2011

Printed on recycled paper

Introduction

During the early opening of the 

Atlantic Ocean in the Mesozoic Era, 

numerous extensional basins formed along 

the eastern margin of the North American 

continent from Florida northward to New 

England and parts of adjacent Canada. The 

basins extend generally from the offshore 

Atlantic continental margin westward 

beneath the Atlantic Coastal Plain to 

the Appalachian Mountains. Using a 

geology-based assessment method, the 

U.S. Geological Survey (USGS) estimated 

a mean undiscovered natural gas resource 

of 3,860 billion cubic feet and a mean 

undiscovered natural gas liquids resource 

of 135 million barrels in continuous 

accumulations within five of the East 

Coast Mesozoic basins (fig. 1; table 1): 

the Deep River, Dan River-Danville, and 

Richmond basins, which are within the 

Piedmont Province of North Carolina and 

Virginia; the Taylorsville basin, which is 

almost entirely within the Atlantic Coastal 

Plain Province of Virginia and Maryland; 

and the southern part of the Newark basin 

(herein referred to as the South Newark 

basin), which is within the Blue Ridge 

Thrust Belt Province of New Jersey 

(fig. 1). The provinces, which contain 

these extensional basins, extend across 

parts of Georgia, South Carolina, North 

Carolina, Virginia, Maryland, Delaware, 

Pennsylvania, New Jersey, New York, 

Connecticut, and Massachusetts (fig. 1). 

The basins formed along the continental margin in response to the regional 

uplift, extension (rifting), and crustal 

thinning that occurred during the early 

opening of the Atlantic Ocean in middle 

Carnian (Late Triassic) time, approximately 227 million years ago. The basins 

were filled with a variety of sediments 

as they formed, including boulder beds, 

coarse-grained fluvial to deltaic sandstones, red siltstones, mudstones, gray and 

black shales, and coal. These deposits 

represent the diverse fluvial to deltaic 

and lacustrine environments that existed 

within the basins. The rifting ended 

early in the Jurassic with the onset of 

regional volcanism and intrusion of 

diabase dikes and sills.

Source Rocks

The source rocks for oil and gas 

within the Mesozoic basins include the 

gray and black shales and the coal beds. 

The shales accumulated in nearshore 

deltas, in interdistributary bays, and 

in the deeper portions of the lakes that 

Figure 1. Map of the Eastern United States showing the locations of the five quantitatively 

(volumetrically) assessed East Coast Mesozoic basins, the nine basins that were not 

volumetrically assessed, and the U.S. Geological Survey province boundaries. Each basin 

includes one continuous gas assessment unit (tables 1, 2).

EXPLANATION

Assessed basin

Unassessed basin

Appalachian Basin Province

Blue Ridge Thrust Belt Province

Piedmont Province 

Atlantic Coastal Plain Province

New England Province

0 120 240 Miles

0 140 280 Kilometers

VIRGINIA

NORTH CAROLINA

SOUTH CAROLINA

GEORGIA

FLORIDA

ALABAMA

TENNESSEE

KENTUCKY

INDIANA

MICHIGAN

OHIO

PENNSYLVANIA

MASS.

CONN.

VT.

R.I.

NEW

JERSEY

NEW YORK

WEST

VIRGINIA

North Florida basin

Florence basin

Cumberland–

Marlboro basin

Dan River–

Danville basin

South Georgia

basin

Culpeper basin

Richmond basin

Deep River basin

Gettysburg basin

Hartford basin

North Newark basin

South Newark basin

Delmarva basins

Taylorsville basin

CANADA

UNITED STATES

87° 83° 79° 75° 71°

42°

38°

34°

30°
occupied the basins. The majority of the 

coal accumulated in marshes and swamps 

that developed around the basin margins 

early in the depositional history of the 

basins. In addition, smaller amounts 

of coal accumulated locally within the 

overlying deltaic deposits. Black shale 

beds may range in thickness from a few 

feet to several hundred feet. Kerogen in 

these beds generally consists of material 

derived from vascular plants and algae, 

which are the types of kerogen that are 

prone to yield both gas and oil. With 

respect to the generation of liquid hydrocarbons, the thermal maturation values of 

the source rocks range widely from basin 

to basin, from within the zone of dry gas 

to immature. The potential reservoirs in 

these basins are continuous accumulations 

that encompass a variety of lithologies 

ranging from boulder conglomerates and 

very coarse sandstones to mudstone, shale, 

and coal. The shale beds that are interbedded with coarser grained strata may act 

effectively as seals.

Resource Summary

The assessment of the East Coast 

Mesozoic basins is based on the geologic 

and geochemical characteristics of the 

individual total petroleum systems (TPS) 

that were recognized within the basins. 

For the petroleum source rock, the 

characteristics include the source rock 

richness, thermal maturation, timing of 

petroleum generation, and migration; for 

the reservoir rocks and seals, they include 

their stratigraphic position and content 

and petrophysical properties. Using this 

Table 1. East Coast Mesozoic basin assessment results.

[MMBO, million barrels of oil; BCFG, billion cubic feet of gas; MMBNGL, million barrels of natural gas liquids; TPS, total petroleum system; AU, assessment unit. Results shown are fully 

risked estimates. For gas accumulations, all liquids are included as NGL (natural gas liquids). F95 represents a 95-percent chance of at least the amount tabulated; other fractiles are defined 

similarly. Fractiles are additive under the assumption of perfect positive correlation. Gray shading indicates not applicable]

Total Petroleum System (TPS) 

and Assessment Unit (AU)

Field 

type

Total undiscovered resources

Oil (MMBO) Gas (BCFG) NGL (MMBNGL)

F95 F50 F5 Mean F95 F50 F5 Mean F95 F50 F5 Mean

Taylorsville Basin Composite TPS

Taylorsville Basin Continuous 

Gas AU Gas 516 985 1,880 1,064 16 34 71 37

Richmond Basin Composite TPS

Richmond Basin Continuous 

Gas AU Gas 99 194 382 211 4 10 20 11

Newark Basin Composite TPS

South Newark Basin Continuous 

Gas AU Gas 363 785 1,698 876 1 4 10 4

Deep River Basin Composite TPS

Deep River Basin Continuous 

Gas AU Gas 779 1,527 2,990 1,660 35 75 158 83

Dan River-Danville Basin Composite TPS

Dan River-Danville Basin 

Continuous Gas AU Gas 17 42 106 49 0 0 1 0

Total continuous resources 1,774 3,533 7,056 3,860 56 123 260 135

Table 2. East Coast Mesozoic basins with 

probable total petroleum systems that were not 

quantitatively assessed, showing type of total 

petroleum system and assessment unit.

Basin

Type of total 

petroleum 

system

Type of 

assessment 

unit

Hartford Composite Continuous gas

North Newark 

(northern half of 

Newark basin)

Composite Continuous gas

Gettysburg Composite Continuous gas

Culpeper Composite Continuous gas

Delmarva (basins) Composite Continuous gas

CumberlandMarlboroComposite Continuous gas

Florence Composite Continuous gas

South Georgia Composite Continuous gas

North Florida Composite Continuous gas

geologic framework, the USGS defined 

a composite TPS and an assessment unit 

(AU) for continuous accumulations in 

each of the 14 major East Coast Mesozoic 

rift basins. The basins are present 

both onshore and offshore (in Stateadministered waters) of the Eastern United 

States (fig. 1). The USGS quantitatively 

assessed the technically recoverable, 

undiscovered resources within five of the 

total petroleum systems and associated 

assessment units that demonstrated the 

most potential for generating and accumulating hydrocarbons (fig. 1; tables 1, 2). 

Several assessment units appear to contain 

continuous accumulations of gas, within 

both the shale and coal source rocks 

and within the adjacent coarser grained, 

siliciclastic strata. Small amounts of oil 

and petroliferous hydrocarbons, such as 

asphalt, have been detected in some of the 

wells drilled in these basins.

For the total of the continuous 

resources, the USGS estimated a mean 

of 3,860 billion cubic feet of gas and a 

mean of 135 million barrels of natural 

gas liquids (table 1). The available data 

indicate that, of the five basins that were 

quantitatively assessed, the Deep River, 

Taylorsville, and South Newark basins 

appear to possess the potential to produce 

the most hydrocarbons (table 1). 

For Further Information

More information about the East 

Coast Mesozoic basins and the assessment 

methodology, as well as other oil and gas 

assessments, total petroleum systems, and 

assessment units may be found at this USGS 

Web site: http://energy.usgs.gov.

East Coast Mesozoic Basin 

Assessment Team 

Robert C. Milici (rmilici@usgs.gov), 

James L. Coleman, Elisabeth L. Rowan, 

Troy A. Cook, Ronald R. Charpentier, 

Mark A. Kirschbaum, Timothy R. Klett, 

Richard M. Pollastro, and Christopher J. 

Schenk.

Acknowledgments

The East Coast Mesozoic Basin 

Assessment Team acknowledges the 

Directors and staff of the State geological 

surveys of North Carolina, Virginia, 

Pennsylvania, and New Jersey for providing geological information and assisting 

with the basin-analysis workshops, which 

were held in preparation for the assessment.