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Concretion. A concretion is a hard, compact mass formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. [1] Concretions are often ovoid or spherical in shape, although irregular shapes also occur.
Uluru (Ayers Rock) is a large sandstone formation in Northern Territory, Australia.. Sedimentary rocks can be subdivided into four groups based on the processes responsible for their formation: clastic sedimentary rocks, biochemical (biogenic) sedimentary rocks, chemical sedimentary rocks, and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.
Pseudofossils are inorganic objects, markings, or impressions that might be mistaken for fossils. Pseudofossils may be misleading, as some types of mineral deposits can mimic lifeforms by forming what appear to be highly detailed or organized structures. One common example is when manganese oxides crystallize with a characteristic treelike or ...
Conglomerate (/ kənˈɡlɒmərɪt /) is a sedimentary rock made up of rounded gravel -sized pieces of rock surrounded by finer-grained sediments (such as sand, silt, or clay). The larger fragments within conglomerate are called clasts, while the finer sediment surrounding the clasts is called the matrix. The clasts and matrix are typically ...
Dakota Formation / Group. The Dakota is a sedimentary geologic unit name of formation and group rank in Midwestern North America. The Dakota units are generally composed of sandstones, mudstones, clays, and shales deposited in the Mid-Cretaceous opening of the Western Interior Seaway. [7]
Lithification (from the Ancient Greek word lithos meaning 'rock' and the Latin -derived suffix -ific) is the process in which sediments compact under pressure, expel connate fluids, and gradually become solid rock. Essentially, lithification is a process of porosity destruction through compaction and cementation.
Dinosaur Ridge. Dinosaur Ridge is a segment of the Dakota Hogback in the Morrison Fossil Area National Natural Landmark located in Jefferson County, Colorado, near the town of Morrison and just west of Denver. In 1876, fossil excavation began at Dinosaur Ridge under the direction of Yale paleontologist Dr. Othniel Charles Marsh. [1]
Assessment of the changing paleoclimate conditions during soil evolution can be explored by analyzing the nodule's concretion structure when combined with dating techniques. [2] Manganese layers typically form at higher redox potentials compared to iron layers, but a period of rapid increase in redox potential can form a mixed layer. [2]