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The Formation is associated with deposits of the Chalk Group, subsequent Palaeogene and Neogene strata, and occasionally Upper Greensand. [2] It occurs in sheets or patches of various sizes over a large area in the south of England, from Hertfordshire on the north to Sussex on the south, and from Kent on the east to Devon on the west.
Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, [1] [2] categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start fires. Flint occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones.
Flint clay can be either detrital or authegenic in origin. Detrital flint clays consist of kaolinite-rich sediments eroded and transported from uplands deeply weathered under tropical climates and redeposited within the coastal plains, in which coal-bearing strata accumulated.
Glacial deposits are mined for aggregates, glacial till and lacustrine deposits formed the parent soil for the state's farmlands, and glacial lakes are the backbone of Minnesota's tourist industry. These economic assets have in turn dictated the state's history and settlement patterns, and the trade and supply routes along the waterways ...
Vaqueros Formation sandstone with concretions A mosaic of images showing spherules, some partly embedded, spread over (smaller) soil grains on the Martian surface. Concretions are found in a variety of rocks, but are particularly common in shales, siltstones, and sandstones. [30]
The original soil surface is buried, and the formation process must begin anew for this deposit. Over time the soil will develop a profile that depends on the intensities of biota and climate. While a soil can achieve relative stability of its properties for extended periods, [ 117 ] the soil life cycle ultimately ends in soil conditions that ...
Upper Mercer flint or Upper Mercer chert is a type of flint, or a pure form of chert, found in Coshocton, Hocking, and Perry counties of Ohio. Made of forms of silica and quartz , the hard and brittle stone was used by prehistoric people to make tools and weapons.
Head describes deposits consisting of fragmented material which, following weathering, have moved downslope through a process of solifluction.The term has been used by British geologists since the middle of the 19th century to describe such material in a range of different settings from flat hilltops to the bottoms of valleys. [1]