The Richmond Basin was one of the

Eastern North America Rift Basins The Eastern North America Rift Basins are a series of sediment-filled '' aborted rifts'' created by large-scale continental extension. Their positions closely mirror the eastern coast of North America. Sediments and volcanic material from the rift ...

. It lies over

Swift Creek Reservoir The Swift Creek Reservoir is a , , man made lake in Chesterfield County, Virginia. It is deep at the channel and deep on average. It provides 20 percent of the county's water supply, and has a watershed Watershed is a hydrological term, which h ...

from

Interstate 64 Interstate 64 (I-64) is an east–west Interstate Highway in the Eastern United States. Its western terminus is at I-70, U.S. Route 40 (US 40), and US 61 in Wentzville, Missouri. Its eastern terminus is at an interchang ...

to the

Appomattox River The Appomattox River is a tributary of the James River, approximately long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed April 1, 2011 in central and eastern Virginia in the United S ...

Extent

The Richmond Basin is a

rift basin 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 wi ...

, making a north to south double pointed oval, with the eastern edge over the

, with the northern point at interstate 64, spanning the

James River The James River is a river in the U.S. state of Virginia that begins in the Appalachian Mountains and flows U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed April 1, 2011 to Chesap ...

, with the southern point at the

Richmond Basin geology

The Richmond Basin is 205 to 245 million years old.

Pangea 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 ...

divided and many small rifts split opened in the earth in addition to the large one that became the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

. When Richmond rift opened and filled with swamps from water in the

Pamunkey River The Pamunkey River is a tributary of the York River, about long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed April 1, 2011 in eastern Virginia in the United States. Via the York Rive ...

, sediment filled in over the swamps and the

sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

pressure converted organic plant material into

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when ...

. This weight is less pressure than coal deposits created when the

continents A continent is any of several large landmasses. Generally identified by convention rather than any strict criteria, up to seven geographical regions are commonly regarded as continents. Ordered from largest in area to smallest, these seven ...

were pushing together and raising up mountains. Semi-anthracite and

anthracite Anthracite, also known as hard coal, and black coal, is a hard, compact variety of coal that has a submetallic luster. It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the hig ...

are often created by such

tectonic Tectonics (; ) are the processes that control the structure and properties of the Earth's crust and its evolution through time. These include the processes of mountain building, the growth and behavior of the strong, old cores of continents ...

squeezing when continents push together. The Richmond Basin has

Bituminous coal Bituminous coal, or black coal, is a type of coal containing a tar-like substance called bitumen or asphalt. Its coloration can be black or sometimes dark brown; often there are well-defined bands of bright and dull material within the seams. It ...

, created by the sedimentary weight only. The coal deposits were on a thin

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especiall ...

and

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicat ...

layer over the

granite Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies un ...

bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of be ...

Oolite Oolite or oölite (''egg stone'') is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Ancient Greek word for egg (ᾠόν). Strictly, oolites consist of ooids of diameter 0.25� ...

or small round grains of calcium carbonate was over the coal. Some coke with and without

sulphur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

was with the coal. To the northwest of the basin is the ''Goochland Terrane'', and between them is the

Boscobel complex The Boscobel complex (originally "Boscabel bowlder beds") is unit of interlayered granite and gneiss within Goochland and Powhatan Counties, Virginia. The area had been mapped as the ''Petersburg Granite'' in 1970 by B. K. Goodwin. The compl ...

.David B. Spears, Nick H. Evans, Patrick C. Finnerty, and Katherine E. Lang, 2022. ''The Goochland Terrane Revisited – Insights from Recent Mapping, Geophysics, and Geochronology''. The 52nd Annual Virginia Geological Field Conference, November 11 - 12, 2022. (Fieldtrip guidebook)

Richmond Basin mining

The Richmond Basin is located near

Midlothian, Virginia Midlothian ( ) is an unincorporated area in Chesterfield County, Virginia, U.S. Settled as a coal town, Midlothian village experienced suburbanization effects and is now part of the western suburbs of Richmond, Virginia south of the James Rive ...

, in

Chesterfield County, Virginia Chesterfield County is located just south of Richmond in the Commonwealth of Virginia. The county's borders are primarily defined by the James River to the north and the Appomattox River to the south. Its county seat is Chesterfield Court Ho ...

. It was mined in the early 18th century. Coal was carried on the Chesterfield Railroad in gravity and mule-pulled carts to

Manchester, Richmond, Virginia Manchester is a former independent city in Virginia in the United States. Prior to receiving independent status, it served as the county seat of Chesterfield County, between 1870 and 1876. Today, it is a part of the city of Richmond, Virginia. ...

and

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 ...

. Wood burning trains, such as the Clover Hill Railroad then the

Brighthope Railway In 1886, Randolph Harrison, of the Virginia department of Agriculture, cited Cumberland Mining Company, stating that the United States had purchased stock in the Brighthope Railway. He continued by citing their assertion that extending the railway ...

transported the coal found at Clover Hill in later years. The coal from Midlothian, Virginia was mainly used in Richmond, Virginia and

Petersburg, Virginia Petersburg is an independent city (United States), independent city in the Commonwealth (U.S. state), Commonwealth of Virginia in the United States. As of the 2020 United States Census, 2020 census, the population was 33,458. The Bureau of Econ ...

. The

Clover Hill Pits The Clover Hill Pits are a number of coal shafts and mines that operated in the Southside area of Richmond, Virginia from 1837 until around 1883. History In 1837, coal was found after a heavy rain at Clover Hill Plantation, in Chesterfield County ...

Winterpock, Virginia Winterpock is an unincorporated community in western Chesterfield County, Virginia, United States. Winterpock does not have its own post office. History The Clover Hill Pits were coal mines from 1837 to 1883. Many of the miners lived in town ...

were sold as far away as

New York City New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...

from the 1840s to the 1890s. The supply was not as great and as cheap to mine as the

Pocahontas coalfield Pocahontas Coalfield, which is also known as the Flat Top-Pocahontas Coalfield, is located in Mercer County/ McDowell County, West Virginia and Tazewell County, Virginia. The earliest mining of coal in the coalfield was in Pocahontas, Virginia ...

, however and mining the Richmond Basin was ended around 1890. Richmond and Petersburg grew economically because of manufacturing supported by the

and

waterpower, more than from coal brought out of Midlothian and Clover Hill."

References

{{Reflist Geography of Richmond, Virginia Geology of Virginia Mining in Virginia Rift basins Sedimentary basins of North America