Ferricrete is a hard, erosion-resistant layer of

sedimentary rock 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 ...

, usually conglomerate or

breccia Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of ...

, that has been cemented into a duricrust by iron oxides. The iron oxide cements are derived from the oxidation of percolating solutions of iron salts.Dictionary of Mining, Mineral, and Related Terms, 2nd Edition. American Geological Institute in cooperation with the Society for Mining, Metallurgy, and Exploration, Inc., 646 p., . Ferricretes form at or near the land surface and may contain non-local sediments that have been transported from outside the immediate area of the deposit. The name is a combination of ''ferruginous'' and ''concrete''. Synonyms include

ferruginous The adjective ferruginous may mean: * Containing iron, applied to water, oil, and other non-metals * Having rust on the surface * With the rust (color) See also * Ferrous, containing iron (for metals and alloys) or iron(II) cations * Ferric, cont ...

duricrust,

hardpan In soil science, agriculture and gardening, hardpan or soil pan is a dense layer of soil, usually found below the uppermost topsoil layer. There are different types of hardpan, all sharing the general characteristic of being a distinct soil layer ...

and ironpan. Ferricrete near Questa NM

Ferricrete deposits along the

Animas River Animas River (''On-e-mas''; es, Río de las Ánimas) is a river in the western United States, a tributary of the San Juan River, part of the Colorado River System. The Animas-La Plata Water Project was completed in 2015. The project pumps w ...

watershed in

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

have been classified as: *

alluvial Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. All ...

iron oxyhydroxide-cemented conglomerates along old stream channels; *

colluvial Colluvium (also colluvial material or colluvial soil) is a general name for loose, unconsolidated sediments that have been deposited at the base of hillslopes by either rainwash, sheetwash, slow continuous downslope creep, or a variable combinati ...

iron oxyhydroxide-cemented, poorly sorted

s with massive to minor layering subparallel to hillslopes; * iron spring and bog deposits with few or no clasts, exhibiting fine, horizontal lamination; and * manganocrete deposits with gray to black matrix containing abundant manganese oxide minerals.Verplanck, Philip L.; et al.; ''Ferricrete Classification, Morphology, Distribution, and Carbon-14 Age Constraints'' in ''Environmental Effects of Historical Mining, Animas River Watershed, Colorado,'' US Geological Survey, Professional Paper 1651, 2007, p. 72
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/ref> Ferricrete also occurs in the United States in areas of the

Gulf Coastal Plain The Gulf Coastal Plain extends around the Gulf of Mexico in the Southern United States and eastern Mexico. This coastal plain reaches from the Florida Panhandle, southwest Georgia, the southern two-thirds of Alabama, over most of Mississippi, wes ...

and the Atlantic Coastal Plain, and in remote eastern areas of Australia and

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. Ferricrete is used widely in

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...

to create roads in rural areas. It is better known in these regions by its

Afrikaans Afrikaans (, ) is a West Germanic language that evolved in the Dutch Cape Colony from the Dutch vernacular of Holland proper (i.e., the Hollandic dialect) used by Dutch, French, and German settlers and their enslaved people. Afrikaans gra ...

name "Koffieklip" (coffee stone).

References

Sedimentary rocks Pedology {{petrology-stub