The Taylorsville Basin is an early

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

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-grabe ...

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

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

and

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

. 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 approximately 335 million y ...

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 The Newark Supergroup, also known as the Newark Group, is an assemblage of Upper Triassic and Lower Jurassic sedimentary rocks which outcrop intermittently along the United States East Coast. They were deposited in a series of Triassic basins app ...

Extent

The Taylorsville Basin extends for about from just southeast of

Richmond, Virginia (Thus do we reach the stars) , image_map = , mapsize = 250 px , map_caption = Location within Virginia , pushpin_map = Virginia#USA , pushpin_label = Richmond , pushpin_m ...

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. The population of Clinton was 38,760 at the 2020 cens ...

. 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 In geology, tectonostratigraphy is stratigraphy that refers either to rock sequences in which large-scale layering is caused by the stacking of thrust sheets, or nappes, in areas of thrust tectonics or to the effects of tectonics on lithostratigraph ...

intervals, thought to reflect two distinct rift phases. The lower unit is the

Doswell Group The Doswell Formation (also known as the Doswell Group) is a geologic unit of Upper Triassic age, part of the Newark Supergroup. The Doswell Formation was originally named to refer to a geological sequence which forms the lower part of the sediment ...

, which has a more restricted extent, and comprises two formations, the South Anna Formation and the

Falling Creek Formation The Doswell Formation (also known as the Doswell Group) is a geologic unit of Upper Triassic age, part of the Newark Supergroup. The Doswell Formation was originally named to refer to a geological sequence which forms the lower part of the sediment ...

. 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 o ...

, 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 Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismi ...

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-J ...

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

References

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