The Taylorsville Basin is an early

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...

basin that either outcrops, or is present beneath younger deposits, in

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and

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

. It is part of the chain of rift basins along the eastern part of North America that formed during the break-up of the

Pangaea Pangaea or Pangea ( ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous period approximately 335 mi ...

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ...

. It is filled by a fluvial and lacustrine sedimentary sequence of the Newark Supergroup.

Extent

The Taylorsville Basin extends for about from just southeast of

Richmond, Virginia Richmond ( ) is the List of capitals in the United States, capital city of the Commonwealth (U.S. state), U.S. commonwealth of Virginia. Incorporated in 1742, Richmond has been an independent city (United States), independent city since 1871. ...

to near

Clinton, Maryland Clinton is an unincorporated census-designated place (CDP) in Prince George's County, Maryland, United States. Clinton was formerly known as Surrattsville until after the time of the Civil War, and Robeystown from 1865 to 1878. The population o ...

. At its broadest it is about wide. Some of its boundaries are poorly defined due to burial by younger Coastal Plain deposits.

Stratigraphy

The sequence is broken down into two tectonostratigraphic intervals, thought to reflect two distinct rift phases. The lower unit is the Doswell Group, which has a more restricted extent, and comprises two formations, the South Anna Formation and the Falling Creek Formation. The upper unit, which is separated from the underlying Doswell Group by an

unconformity An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval ...

, is the King George Group, which comprises three formations, the Newfound Formation, the Port Royal Formation and the Leedstown Formation.

Structure

The Taylorsville Basin is a

half-graben A half-graben is a geological structure bounded by a fault along one side of its boundaries, unlike a full graben where a depressed block of land is bordered by parallel faults. Rift and fault structure A rift is a region where the lithosphere ...

, with the main controlling fault forming the northwestern boundary of the basin. Subsurface data from boreholes and seismic reflection profiles, indicate that the basin was originally a series of smaller half-graben at the time of the deposition of the Doswell Group. The unconformity at the base of the overlying King George Group marks a reorganization of the rift geometry with further extension being accommodated on a single basin-bounding fault zone, giving a simple NW-thickening wedge in this upper interval. The basin was inverted during the

Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic� ...

, soon after the rifting stopped, forming NE-trending folds over intrabasinal normal faults.

References

{{Reflist Sedimentary basins of North America Mesozoic rifts and grabens