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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.
Weathering is relatively slow, with basalt becoming less dense, at a rate of about 15% per 100 million years. The basalt becomes hydrated, and is enriched in total and ferric iron, magnesium, and sodium at the expense of silica, titanium, aluminum, ferrous iron, and calcium. [52]
The dykes are of variable composition but are generally of the alkaline-basalt type. The east–west trending Swynnerton fault offsets the dyke in a sinistral manner. Spheroidal weathering of exposed sections of the dykes has focussed on cooling joints present within the body of intrusive rock.
Although sometimes confused with weathering rinds, spheroidal weathering is a different type of chemical weathering in which spherical layers of weathered material progressively develop in situ around blocks of jointed bedrock beneath the Earth's surface, rather than in reworked and transported clasts such as cobbles and boulders. [4] [5]
Varioles are millimeter- to centimeter-scale, light-colored, globular to spherical structures, that are conspicuously observable within aphanitic, mafic igneous rocks, such as basalt, komatiite, and tachylite, that comprise either pillow lavas, subaerial lava flows, or volcanic dykes. Typically, they are less resistant to weathering than the ...
It is quite common for spheroidal weathering, a form of chemical weathering, to occur as groundwater circulates through orthogonal joint sets in the near-surface. [10] This process results in the alteration and disintegration of bedrock adjacent to the joints.
The FDA determined that the data presented in a 2022 color additive petition show that this ingredient causes cancer in male laboratory rats exposed to high levels of FD&C Red No. 3 because of a ...
Joints have a profound control on weathering and erosion of bedrock. As a result, they exert a strong control on how topography and morphology of landscapes develop. Understanding the local and regional distribution, physical character, and origin of joints is a significant part of understanding the geology and geomorphology of an area.