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Geologic units containing alluvium

Earth material > Unconsolidated material
Alluvium
A general term for clay, silt, sand, gravel or similar unconsolidated detrital material, deposited during comparatively recent geologic time by a stream or other body of running water, as a sorted or semi-sorted sediment...
Subtopics:
Flood plain
Levee
Delta
Alluvial fan
Alluvial terrace

Alabama - Arkansas - California - Colorado - Florida - Georgia - Idaho - Mississippi - Montana - New Jersey - New Mexico - Nevada - New York - Oklahoma - Pennsylvania - Utah - Virginia - Washington - West Virginia - Wyoming
Alabama
Alluvial, coastal and low terrace deposits (Holocene)
Alluvial, coastal and low terrace deposits - Varicolored fine to coarse quartz sand containing clay lenses and gravel in places. Gravel composed of quartz and chert pebbles and assorted metmorphic and igneous rock fragments in streams near the Piedmont. In areas of the Valley and Ridge province gravel composed of angular to subrounded chert, quartz, and quartzite pebbles. Coastal deposits include fine to medium quartz sand with shell fragments and accessory heavy minerals along Gulf beaches and fine to medium quartz sand, silt, clay, peat, mud and ooze in the Mississippi Sound, Little Lagoon, bays, lakes, streams, and estuaries.
Arkansas
Alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene)
Alluvium - Alluvial deposits of present streams
Alluvium - Alluvial deposits in major stream channels or in mappable meanders of major streams (Phanerozoic | Cenozoic | Quaternary | Holocene)
Alluvial deposits in major stream channels or in mappable meanders of major streams - Includes alluvial deposits in natural levees in some areas.
Alluvium - Alluvial deposits of local streams or of overbank flow of major streams (Phanerozoic | Cenozoic | Quaternary | Holocene)
Alluvial deposits of local streams or of overbank flow of major streams - In some areas includes deposits in abandoned meanders of major streams
Alluvium and terrace deposits (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene)
Alluvium and terrace deposits - Alluvial deposits of present streams and on one or more terrace levels
California
Quaternary alluvium and marine deposits (Pliocene to Holocene)
Alluvium, lake, playa, and terrace deposits; unconsolidated and semi-consolidated. Mostly nonmarine, but includes marine deposits near the coast.
Quaternary sand deposits, unit 2 (inland) (Quaternary)
Extensive marine and nonmarine sand deposits, generally near the coast or desert playas
Colorado
Ancient alluvium (Phanerozoic | Cenozoic | Tertiary Quaternary)
In isolated patches that may not all be of the same age
Gravels and alluviums (Phanerozoic | Cenozoic | Quaternary)
Includes Broadway and Louviers Alluviums
Modern alluvium (Phanerozoic | Cenozoic | Quaternary)
Includes Piney Creek Alluvium and younger deposits
Older gravels and alluviums (Phanerozoic | Cenozoic | Quaternary)
Includes Slocum, Verdos, Rocky Flats, and Nussbaum Alluviums in east, and Florida, Bridgetimber, and Bayfield Gravels in southwest
Unclassified surficial deposits and underlying Alamosa Fm in San Luis Valley (Phanerozoic | Cenozoic | Tertiary Quaternary)
Alamosa Fm: gravel, sand, silt
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.
Georgia
Stream alluvium (Quaternary)
Stream alluvium and undifferentiated terrace deposits
Idaho
Basalt flows, basaltic pyroclastic and clastic debris; Middle Pleistocene canyon-filling and plateau lava flows, pyroclastic debris, alluvium, and colluvium; Snake River Plain (Middle Pleistocene)
Middle Pleistocene plateau and canyon-filling basalt in and near Snake Plain.
Clastic debris; Quaternary colluvium, fanglomerate, talus, and glacial deposits; upland-valley margins (Quaternary)
Quaternary colluvium, fanglomerate, and talus plus some glacial debris in upland valleys.
Glacial debris; Late Pleistocene glacial till, outwash, and alluvium of continental glaciers; northern Idaho (Late Pleistocene )
Pleistocene till, moraines and similar unsorted glacial debris.
Glacial debris; Late Pleistocene till, outwash, and alluvium of valley glaciers; high mountain valleys (Late Pleistocene )
Pleistocene upland valley deposits; commonly derived from alpine glaciation.
Gravel and sand; Middle Pleistocene alluvial pediment gravel (Pleistocene )
Middle Pleistocene deposits; outwash, fanglomerate, flood and terrace gravels.
Gravel; Early Pleistocene alluvium; western Snake River Plain (Pleistocene)
Lower Pleistocene deposits; outwash, fanglomerate, flood and terrace gravels.
Gravel, sand, and silt; glacial outburst flood deposits, outwash, fanglomerate, and alluvium, undivided; Pleistocene (Pleistocene)
Pleistocene outwash, fanglomerate, flood and terrace gravels; sudivisions are: (Qpug, Qpmg, and Qplg).
Gravel, sand, and silt; Quaternary; alluvium (Quaternary)
Quaternary alluvium; may contain some glacial deposits and colluvium in uplands
Gravel, sand, and silt; Quaternary basin-filling alluvium; Snake River Plain, Basin and Range provinces (Quaternary)
Quaternary detritus; generally basin-filling deposits of central and southern Idaho.
Gravel, sand, silt, clay; Late Pleistocene glacio-alluvial and lacustrine deposits; Basin and Range, and Snake River Plain (Late Pleistocene)
Upper Pleistocene deposits; outwash, fanglomerate, flood and terrace gravels.
Silt, clay, and diatomite; Middle Pleistocene lacustrine sediments of lava-dammed lakes; western Snake River Plain (Middle Pleistocene)
Middle Pleistocene lava-dammed Snake Plain lake beds of silt, clay and diatomite.
Silt, clay, sand, and gravel; Quaternary-Tertiary alluvial and lacustrine deposits; western Snake River Plain (Early Pleistocene and Late Pliocene)
Pleistocene and Pliocene stream and lake deposits.
Mississippi
Alluvium (Holocene)
Alluvium - Loam, sand, gravel, and clay; mapped only in Mississippi River Alluvial Plain.
Montana
Alluvium (Phanerozoic | Cenozoic | Quaternary)
Alluvium: mainly valley fill consisting of silt, sand, and gravel; includes some terrace deposits and glacial drift of Pleistocene age in some areas; locally includes hot spring tufa. The older part of the alluvium, where present, is probably of Pliocene age.
Glacial drift (Phanerozoic | Cenozoic | Quaternary)
Glacial drift: morainal and outwash plain deposits of mountain glaciers; mainly ill-sorted and poorly rounded boulders, cobbles, pebbles, and sand; may include alluvium in places
New Jersey
Belleplain Member of the Kirkwood Formation (middle Miocene, Serravallian)
Belleplain Member - New member named for a corehole at Belleplain State Forest headquarters (Belleplain II). A thin gravel bed, containing gravel up to 1 cm (0.4 in) in diameter, is present along the contact with the underlying Wildwood Member. The gravel is mainly quartz with small amounts of phosphatized vertebrate remains and sharks teeth. The lower 10.5 m (34 ft) is massive to horizontally laminated, very diatomaceous, dark-gray clay or silty clay with common, small, thin-walled mollusks. This basal clayey unit is overlain by as much as 23 m (75 ft) of mostly sand. The lower 1.2 m (4 ft) of fine- to medium-grained, dark-gray, woody sand is interbedded with clay. These grade up into a fine- to medium-grained, massive, rarely crossbedded, medium- to dark-gray, micaceous, bioturbated, quartz sand. The sand in the upper 10.5 m (34 ft) of this interval becomes coarser grained and is extensively stained gray brown by humates. Sand in the Belleplain is mostly quartz with a minor amount of siliceous rock fragments. Potassic feldspar is a common constituent but typically is less than 10 percent of the sand fraction. The upper 10 m (33 ft) is finely laminated, dark-gray clay with common, thin interbeds of fine- to medium-grained, micaceous quartz sand. Flaser bedding is common in this upper clayey unit. Gamma-ray values are high for the clayey unit at the base (transgressive deposits) and low for the sandy unit above (regressive deposits). This high-low couplet is a distinctive gamma-ray pattern that is typical of most marine units in the New Jersey Coastal Plain (unconformity-bounded sequences that represent an asymmetric transgressive to regressive cycle of sedimentation). The Belleplain is restricted to the southern bedrock sheet and generally occurs in the subsurface except where younger Pleistocene units have deeply entrenched through the overlying Cohansey Formation and exposed it. The Belleplain is greater than 100 m (338 ft) thick along the coast from Strathmere, Cape May County, to Cape May, Cape May County. The age of the Belleplain was determined by using a combination of different fossil types. Andrews (1988) considers the diatom assemblage of Actinoptychus marylandicus, Coscinodiscus lewisianus, Delphineis angustata, D. novaecaesaraea, D. penelliptica, Rhaphoneis clavata, R. gemmifera, and R. scutula to be characteristic of East Coast Diatom Zone (ECDZ) 6 or Bed 15 (equivalent to the uppermost part of the Calvert Formation of the Chesapeake Bay region). Silicoflagellates recovered from the Belleplain include Corbisema triacantha, Distephanus crux crux, and D. stauracanthus. The co-existence of the diatom Coscinodiscus lewisianus with the silicoflagellate Distephanus stauracanthus indicates an age of 13.2 to 12.3 Ma (David Bukry, written commun., 1990). Strontium-isotope ages of the shells range from 14.7 to 12.3 Ma and confirm the paleontologic middle Miocene age. Pollen assemblages from the base of this formation in the Belleplain I core contain spruce, pine, oak, hickory, and poplar (all abundant) with black gum, sweet gum, maple, birch, and Myrica (all sparse). Exotics include Clethra, Cyrilla, Engelhardia/Momipites, Planera, Podocarpus, and Symplocos. This assemblage is a mixture of cooltemperate forms (spruce) and warm-temperate forms (oak, hickory, and exotics; a lowland assemblage). The pollen assemblage in the upper part of the formation lacks the cool-temperate elements and is, overall, a warm-temperate microflora, thus indicating a general warming of the climate during the time of deposition
Cohansey Formation (Middle Miocene, Serravallian)
Cohansey Formation - Sand, fine- to coarse-grained, locally gravelly, massive to crossbedded, gray-brown or dark-gray; weathers yellow to white. Typically, the weathered sand is nearly all quartz or rock fragments of orthoquartzite. Where less weathered, small amounts (5-10 percent) of potassium feldspar are present. Interbedded with discrete beds of clay or silty clay, thin- to thick-bedded, massive to finely laminated, dark-gray; weathers white, yellow, or red. Darkgray beds commonly contain carbonized wood fragments, some of which are log size. The thicker clay beds occur in lenses that commonly have small to very large pieces of lignitized wood. An extensive, well-preserved leaf flora was collected from a very thick clay lens in the Cohansey near Millville, Cumberland County. The leaf flora were dominated by Alangium sp., a tree no longer growing in eastern North America (J.A. Wolfe, written commun., 1992). Locally, formation consists of several thin- to thickbedded, upward-coarsening sections (clay to sand). The depth of weathering ranges from 24 m (79 ft) in the ACGS-4 corehole near Mays Landing, Atlantic County (Owens and others, 1988), to 70 m (230 ft) in the Atlantic City corehole (F-F'). In the southern part of the southern sheet, in the Belleplain State Forest, Cape May County (G-G'), the formation consists of thin to thick beds of fine- to medium-grained, micaceous quartz (both colorless and green) sand and dark-gray to grayish-brown, woody clay. The sand is locally coarsely stratified (typically small-amplitude crossbeds) and locally highly bioturbated. The clay is extensively bioturbated. These beds represent the deepest marine beds found in the Cohansey in the New Jersey Coastal Plain. The basal contact with underlying units has considerable relief. The contact is sharp and commonly consists of a thin bed of fine gravelly sand. The original thickness of the Cohansey is difficult to ascertain because of extensive erosion. The formation lies in a broad channel and is thickest in the thalweg near Atlantic City where it is nearly 107 m (351 ft) thick. The base of the formation rises rapidly to the south and north of this channel axis. In downdip areas near Belleplain State Forest, the Cohansey contains marginal marine and shelfal facies. The shelfal facies is composed of interbedded, highly bioturbated, micaceous, slightly glauconitic quartz sand and massive clay. Most of the sand in the Cohansey is medium grained and moderately sorted although coarse and fine sandy beds also are common. Beds that have gravel as a major component are locally common in the mixed marine-nonmarine facies in the northeastern corner of the southern sheet. Here, the gravel occurs in well-defined channels. Most of the gravel is 2.5 cm (1 in) or less in diameter, although clasts up to 13 cm (5 in) in diameter have been locally observed. The gravel is mostly quartz or quartzite with lesser amounts of white and black chert. Previously, the age of the Cohansey was postulated from its stratigraphic position, its perceived contact relations with the underlying Kirkwood Formation (conformable or unconformable), and its macro- and microflora. The palynology of upper Tertiary formations in the northeastern United States is, however, only generally understood. Commonly, Pliocene beds have less exotic species than Oligocene or Miocene beds. If this is the case, then the Cohansey, which has a large number of exotics of some species, has more Miocene affinities than Pliocene, an age some have assigned to this formation. Ager (in Owens and others, 1988) discusses the microflora in the Cohansey near Mays Landing. He notes that the Cohansey has a large number of exotics similar to those in the underlying Wildwood Member of the Kirkwood, and because of this, thought the Cohansey to be Miocene. Pollen from the Cohansey at Belleplain also has a large variety of exotics in a warm temperate to subtropical pollen assemblage (Les Sirkin, Adelphi University, oral commun., 1991), which includes Clethra, Cyathea, Cyrilla, Engelhardia, Epilobium, Gordonia, Planera, Podocarpus, Pterocarya, and Symplocos. The major sources of tree pollen at Belleplain are pine, oak, and hickory. The contained dinocyst flora from marine beds at Belleplain can be correlated with the known dinocyst assemblages from the Choptank and the lower part of the St. Marys Formation of the Chesapeake Bay region and therefore is middle Miocene in age (Laurent de Verteuil, University of Toronto, written commun., 1991). These dinoflagellate data therefore confirm the Miocene rather than Pliocene age for the Cohansey. The strontium-isotope age from shells at the base of the Cohansey in an offshore well (ACOW-1) was approximately 11 Ma or latest middle Miocene or late Serravallian
New Mexico
alluvium (Phanerozoic | Cenozoic | Quaternary)
Alluvium; upper and middle Quaternary
Hinsdale Basalt (Phanerozoic | Cenozoic | Tertiary)
Hinsdale Basalt; northern Taos and eastern Rio Arriba Counties; basalt flows interbedded with Los Pinos Formation
lacustrine and playa-lake deposits (Phanerozoic | Cenozoic | Quaternary)
Lacustrine and playa-lake deposits; includes associated alluvial and eolian deposits of major lake basins; upper Quaternary
Ogallala Formation (Phanerozoic | Cenozoic | Tertiary)
Ogallala Formation, alluvial and eolian deposits, and petrocalcic soils of the southern High Plains; Lower Pliocene to middle Miocene (locally includes unit Qoa)
older alluvial deposits of upland plains and piedmont areas (Phanerozoic | Cenozoic | Quaternary)
Older alluvial deposits of upland plains and piedmont areas, and calcic soils and eolian cover sediments of High Plains region; includes scattered lacustrine, playa, and alluvial deposits of the Tahoka, Double Tanks, Tule, Blanco, Blackwater Draw, and Gatuna Formations, the latter of which may be Pliocene at base; outcrops, however, are basically of Quaternary deposits; upper Quaternary to uppermost Pliocene(?)
older piedmont alluvial deposits and shallow basin fill (Phanerozoic | Cenozoic | Tertiary Quaternary)
Older piedmont alluvial deposits and shallow basin fill; includes Quemado Formation and in northeast, high level pediment gravels
piedmont alluvial deposits (Phanerozoic | Cenozoic | Quaternary)
Piedmont alluvial deposits: upper and middle Quaternary; includes deposits of higher gradient tributaries bordering major stream valleys, alluvial veneers of the piedmont slope, and alluvial fans
Nevada
Alluvial deposits (Quaternary)
ALLUVIAL DEPOSITS-Locally includes beach and sand dune deposits
Older alluvial deposits (Miocene to Quaternary)
OLDER ALLUVIAL DEPOSITS
Playa, marsh, and alluvial-flat deposits, locally eroded (Quaternary)
PLAYA, MARSH, AND ALLUVIAL-FLAT DEPOSITS, LOCALLY ERODED
New York
Glacial and Alluvial Deposits (Quaternary)
Glacial and Alluvial Deposits - underlying bedrock geology unknown.
Glacial and Alluvial Deposits (Quaternary)
Glacial and Alluvial Deposits - underlying bedrock geology unknown.
Glacial and Alluvial Deposits (Quaternary)
Glacial and Alluvial Deposits - underlying bedrock geology unknown.
Oklahoma
Alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene)
CIMARRON- Clay, silt, sand, and gravel 0 to 100 feet thick. TEXAS- Sand, silt, clay, and gravel located in valleys of principal streams. Thickness not known but may exceed 100 feet in North Canadian River valley and may be 50 to 100 feet in lower parts of valleys of Coldwater and Palo Duro Creeks BEAVER - Sand, gravel, silt, and clay in discontinuous lenses along courses of larger streams. 0-50 feet thick
Alluvium (Phanerozoic | Cenozoic | Quaternary | Holocene)
WOODWARD- Lenticular and interfingering deposits of gravel, sand, silt, and clay. Generally light-tan to gray. Thickness along major streams ranges up to 100 feet and probably averages 40 feet; along minor streams the thickness ranges up to 45 feet and probably averages 20 feet. ENID- Sand, silt, clay, and locally gravel. Maximum thickness ranges from 30 to 80 feet (9 to 24 m) along major streams and from 0 to 60 feet (0 to 18 m) along minor streams. TULSA- Gravel, sand, silt, and clay. TULSA- Gravel, sand, silt, and clay. OKLAHOMA CITY- Sand, silt, clay, and lenticular beds of gravel. Thickness ranges from about 30 to 100 feet and probably averages about 50 feet along major streams. Along minor streams, thickness ranges from a few feet to about 50 feet and probably averages about 25 feet. LAWTON- Sand, clay, and gravel as much as 50 feet (15 m) thick; Shown only along major streams and tributaries . ARDMORE-SHERMAN- Gravel, sand, silt, and clay, including low terraces; thickness, about 25 to 100 feet. McALESTER TEXARKANA- Gravel, sand, silt, and clay, including low terraces about 30 feet above channels; thickness, about 50 feet along Little River and 110 feet along Red River
Pennsylvania
Trenton Gravel (Quaternary)
Trenton Gravel - Gray or pale-reddish-brown, very gravelly sand interstratified with crossbedded sand and clay-silt beds; includes areas of Holocene alluvium and swamp deposits.
Utah
Older Quaternary alluvial deposits (Quaternary)
Pliocene and Quaternary alluvial material (Pliocene to Quaternary)
Quaternary alluvium and colluvium (Quaternary)
Tertiary (4) sedimentary rocks in central Utah (Middle Miocene to Late Pliocene)
Tertiary (4) sedimentary rocks in Salt Lake City-Coalville-Randolph region (Middle Miocene to Late Pliocene)
Tertiary (4) sedimentary rocks in western Utah (Middle Miocene to Late Pliocene)
Virginia
Alluvium (Quaternary)
Alluvium - Poorly sorted organic material, clay, sand, and rounded pebbles and cobbles
Quaternary and Tertiary Deposits (Tertiary-Quaternary)
Quaternary and Tertiary Deposits - Tabb through Windsor Formations and alluvial/tidal prism deposits.
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.
Glacial drift, undivided (Pleistocene)
Glacial and glaciofluvial sand, gravel, and till; includes alpine glacier outwash and till as well as some Recent alluvium.
Glaciolacustrine deposits (Pleistocene)
Fine-grained sand and silt, well-stratified, with some gravel, clay, and diatomaceous earth. Contains clastic dikes in Walla Walla area.
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.
Pliocene nonmarine rocks (Pliocene)
Conglomerate, sandstone, shale, and mudstone. Tuffaceous in part; contains alluvial fan type material locally.
Quaternary nonmarine deposits (Pleistocene)
Predominantly a well-cemented, heterogeneous mixture of volcanic gravel, sand, silt, and clay. Contains some till and in western Washington is commonly deeply weathered.
Younger glacial drift (Pleistocene)
Younger glacial drift, undivided. Till, outwash, and associated deposits; sorted and unsorted sand, gravel, silt, and clay. Includes some alluvium.
Younger glacial drift (Pleistocene)
Advance and recessional outwash, stratified drift, and associated deposits. Primarily silt, sand, and gravel with some clay. Includes alluvium locally and scabland deposits of eastern Washington.
West Virginia
Quaternary Alluvium (Quaternary)
Quaternary Alluvium - alluvial deposits of sand, gravel, silt, and clay.
Wyoming
Alluvium and Colluvium (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene)
ALLUVIUM AND COLLUVIUM--Clay, silt, sand, and gravel in flood plains, fans, terraces, and slopes.
Undivided surficial deposits (Phanerozoic | Cenozoic | Quaternary | Pleistocene Holocene)
UNDIVIDED SURFICIAL DEPOSITS--Mostly alluvium, colluvium, and glacial and landslide deposits. Primarily in Yellowstone area and Bighorn Mountains.

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