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Spheroidal weathering is the result of chemical weathering of systematically jointed, massive rocks, including granite, dolerite, basalt and sedimentary rocks such as silicified sandstone. It occurs as the result of the chemical alteration of such rocks along intersecting joints.
Within the weathering environment, chemical oxidation of a variety of metals occurs. The most commonly observed is the oxidation of Fe 2+ ( iron ) by oxygen and water to form Fe 3+ oxides and hydroxides such as goethite , limonite , and hematite .
Spheroidal concretions, as large as 9 m (30 ft) in diameter, have been found eroding out of the Qasr el Sagha Formation within the Faiyum depression of Egypt. [16] Concretions occur in a wide variety of shapes, including spheres, disks, tubes, and grape-like or soap bubble-like aggregates. [17]
The use of weathering rinds in relative dating is widely used in Arctic, Antarctic, and alpine regions and in the correlation of glacial moraines and tills and fluvial sediments and terraces. [6] [7] [8] In addition, weathering rinds have been used to determine the absolute amount of time gravel-size rock has been exposed to the weathering ...
Exfoliating slabs of granite, on Half Dome in Yosemite National Park, USA. Exfoliating granite is a granite undergoing exfoliation, or onion skin weathering (desquamation).The external delaminated layers of granite are gradually produced by the cyclic variations of temperature at the surface of the rock in a process also called spalling.
Tafoni at Salt Point State Park, Sonoma County, California.. Tafoni (singular: tafone) are cavities that develop in granular rock.. Although various definitions [example needed] can be found [by whom?] in the scientific literature, tafoni are commonly defined as small (less than 1 cm (0.39 in)) to large (greater than 1 meter (3.3 ft)) cavity features that develop in either natural or manmade ...
Soil structure affects aeration, water movement, conduction of heat, plant root growth and resistance to erosion. [26] Water, in turn, has a strong effect on soil structure, directly via the dissolution and precipitation of minerals, the mechanical destruction of aggregates [27] and indirectly by promoting plant, animal and microbial growth.
The well-rounded shapes of the individual blocks were formed by spheroidal weathering (Wollsackverwitterung) in the tropical, humid climate of the Cenozoic era. Over the course of time they were left behind as the ground around was eroded; they became unstable and began to shift.