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Geologic units containing peat

Earth material > Unconsolidated material > Biogenic material
Peat
An unconsolidated deposit of semicarbonized plant remains in a water saturated environment, such as a bog or fen, and of persistently high moisture content (at least 75%).
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Florida - Louisiana - North Carolina - Oregon - South Carolina - Virginia - Washington
Florida
Alluvium (Pleistocene/Holocene)
Alluvium - Undifferentiated Quaternary Sediments - Much of Florida's surface is covered by a varying thickness of undifferentiated sediments consisting of siliciclastics, organics and freshwater carbonates. Where these sediments exceed 20 feet (6.1 meters) thick, they were mapped as discrete units. In an effort to subdivide the undifferentiated sediments, those sediments occurring in flood plains were mapped as alluvial and flood plain deposits (Qal). Sediments showing surficial expression of beach ridges and dunes were mapped separately (Qbd) as were the sediments composing Trail Ridge (Qtr). Terrace sands were not mapped (refer to Healy [1975] for a discussion of the terraces in Florida). The subdivisions of the Undifferentiated Quaternary Sediments (Qu) are not lithostratigraphic units but are utilized in order to facilitate a better understanding of the State's geology. The siliciclastics are light gray, tan, brown to black, unconsolidated to poorly consolidated, clean to clayey, silty, unfossiliferous, variably organic-bearing sands to blue green to olive green, poorly to moderately consolidated, sandy, silty clays. Gravel is occasionally present in the panhandle. Organics occur as plant debris, roots, disseminated organic matrix and beds of peat. Freshwater carbonates, often referred to as marls in the literature, are scattered over much of the State. In southern Florida, freshwater carbonates are nearly ubiquitous in the Everglades. These sediments are buff colored to tan, unconsolidated to poorly consolidated, fossiliferous carbonate muds. Sand, silt and clay may be present in limited quantities. These carbonates often contain organics. The dominant fossils in the freshwater carbonates are mollusks.
Trail Ridge sands (Pleistocene)
Trail Ridge Sands - Undifferentiated sediments - Undifferentiated Quaternary Sediments - Much of Florida's surface is covered by a varying thickness of undifferentiated sediments consisting of siliciclastics, organics and freshwater carbonates. Where these sediments exceed 20 feet (6.1 meters) thick, they were mapped as discrete units. In an effort to subdivide the undifferentiated sediments, those sediments occurring in flood plains were mapped as alluvial and flood plain deposits (Qal). Sediments showing surficial expression of beach ridges and dunes were mapped separately (Qbd) as were the sediments composing Trail Ridge (Qtr). Terrace sands were not mapped (refer to Healy [1975] for a discussion of the terraces in Florida). The subdivisions of the Undifferentiated Quaternary Sediments (Qu) are not lithostratigraphic units but are utilized in order to facilitate a better understanding of the State's geology. The siliciclastics are light gray, tan, brown to black, unconsolidated to poorly consolidated, clean to clayey, silty, unfossiliferous, variably organic-bearing sands to blue green to olive green, poorly to moderately consolidated, sandy, silty clays. Gravel is occasionally present in the panhandle. Organics occur as plant debris, roots, disseminated organic matrix and beds of peat. Freshwater carbonates, often referred to as marls in the literature, are scattered over much of the State. In southern Florida, freshwater carbonates are nearly ubiquitous in the Everglades. These sediments are buff colored to tan, unconsolidated to poorly consolidated, fossiliferous carbonate muds. Sand, silt and clay may be present in limited quantities. These carbonates often contain organics. The dominant fossils in the freshwater carbonates are mollusks.
Undifferentiated sediments (Pleistocene/Holocene)
Undifferentiated sediments - Undifferentiated Quaternary Sediments - Much of Florida's surface is covered by a varying thickness of undifferentiated sediments consisting of siliciclastics, organics and freshwater carbonates. Where these sediments exceed 20 feet (6.1 meters) thick, they were mapped as discrete units. In an effort to subdivide the undifferentiated sediments, those sediments occurring in flood plains were mapped as alluvial and flood plain deposits (Qal). Sediments showing surficial expression of beach ridges and dunes were mapped separately (Qbd) as were the sediments composing Trail Ridge (Qtr). Terrace sands were not mapped (refer to Healy [1975] for a discussion of the terraces in Florida). The subdivisions of the Undifferentiated Quaternary Sediments (Qu) are not lithostratigraphic units but are utilized in order to facilitate a better understanding of the State's geology. The siliciclastics are light gray, tan, brown to black, unconsolidated to poorly consolidated, clean to clayey, silty, unfossiliferous, variably organic-bearing sands to blue green to olive green, poorly to moderately consolidated, sandy, silty clays. Gravel is occasionally present in the panhandle. Organics occur as plant debris, roots, disseminated organic matrix and beds of peat. Freshwater carbonates, often referred to as marls in the literature, are scattered over much of the State. In southern Florida, freshwater carbonates are nearly ubiquitous in the Everglades. These sediments are buff colored to tan, unconsolidated to poorly consolidated, fossiliferous carbonate muds. Sand, silt and clay may be present in limited quantities. These carbonates often contain organics. The dominant fossils in the freshwater carbonates are mollusks.
Undifferentiated sediments (Pliocene/Pleistocene)
Undifferentiated sediments - Undifferentiated Tertiary-Quaternary Sediments - These sediments are siliciclastics that are separated from undifferentiated Quaternary sediments solely on the basis of elevation. Based on the suggestion that the Pleistocene sea levels reached a maximum of approximately 100 feet (30 meters) msl (Colquhoun, 1969), these sediments, which occur above 100 feet (30 meters) msl, are predominantly older than Pleistocene but contain some sediments reworked during the Pleistocene. This unit may include fluvial and aeolian deposits. The undifferentiated Tertiary-Quaternary sediments occur in a band extending from the Georgia-Florida state line in Baker and Columbia Counties southward to Alachua County. These sediments are gray to blue green, unconsolidated to poorly consolidated, fine to coarse grained, clean to clayey, unfossiliferous sands, sandy clays and clays. Organic debris and disseminated organics are present in these sediments. The undifferentiated Tertiary-Quaternary sediments are part of the surficial aquifer system.
Louisiana
Delta Plain, Fresh Marsh (Phanerozoic | Cenozoic | Quaternary | Holocene)
gray to black clay of very high organic content, some peat.
Delta Plain, Saline Marsh (Phanerozoic | Cenozoic | Quaternary | Holocene)
gray to black clay of very high organic content, some peat.
North Carolina
Surficial Deposits, Undivided (Quaternary)
Surficial Deposits, Undivided - sand, clay, gravel, and peat deposited in marine, fluvial, eolian, and lacustrine environments. Quaternary deposits not shown at altitudes greater than approx. 205 feet above mean sea level (Suffolk Scarp, in part).
Oregon
Alluvial deposits (Holocene) (Holocene)
Sand, gravel, and silt forming flood plains and filling channels of present streams. In places includes talus and slope wash. Locally includes soils containing abundant organic material, and thin peat beds
South Carolina
Alluvial Valley Swamp (Quaternary)
Alluvial Valley Swamp: Unconformable on all underlying units, fluvial sand and gravel at base, grading upwards into fine sands and silts, local peat. May be overrun with recent sediments from forest cutting and agriculture.
Quaternary undifferentaited (Quaternary)
Quaternary undifferentaited: undifferentiated beach, tidal marsh, and coastal terrace sequence
Swamp (Quaternary)
Swamp: Extensive cypress swamps occur in low-lying poorly-drained bay deposits. Limit of cypress is southern Delaware; from NJ south to Georgia. Atlantic white cedar is original species. Commonly extensive thick peat and buried wood.
Tidal Marsh (Quaternary)
Tidal Marsh: Peat and muck deposits along tidal margins of esturaries and back bays. Deposits range from a few feet to 60+ feet deep. Locally include silt and fine sand and clay as levees on tidal channels. At depth peaty material may be accumulated from fresh water plants. Peat at the surface dominated by spartina and other salt tolerant species.
Virginia
Chuckatuck Formation (Quaternary)
Chuckatuck Formation - Interbedded gravel, sand, silt, clay, and minor peat; at altitudes to 50-60 ft. (top of unit).
Omar Formation - Accomack Member: (Quaternary)
Omar Formation - Accomack Member: sand, gravel, silt, clay, and peat; at altitudes to 50 ft.
Quaternary and Tertiary Deposits (Tertiary-Quaternary)
Quaternary and Tertiary Deposits - Tabb through Windsor Formations and alluvial/tidal prism deposits.
Shirley Formation (Quaternary)
Shirley Formation - Interbedded gravel, sand, silt, clay, and peat; at altitudes to 35-45 ft. (top of unit).
Swamp Deposits (Quaternary)
Swamp Deposits - Peat, mud, and sand.
Tabb Formation (Quaternary)
Tabb Formation - Undifferentiated. Includes the Poquoson Member (Qtp), Lynnhaven Member ( Qtl) and Sedgefield Member (Qts).
Washington
Alluvium (Holocene)
Mostly unconsolidated silt, sand, and gravel valley fill with some clay; includes low-level terrace, marsh, peat, artificial fill, and glacial deposits locally.
Older glacial drift (Pleistocene)
Till, outwash, and associated interglacial deposits; sorted and unsorted gravel, sand, silt, and clay. Includes peat beds and non-glacial sediments locally. Mostly pre-Wisconsin in age.
Younger glacial drift (Pleistocene)
Younger glacial drift, undivided. Till, outwash, and associated deposits; sorted and unsorted sand, gravel, silt, and clay. Includes some alluvium.

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