Argillaceous minerals are minerals containing substantial amounts of clay-like components (Greek: ἄργιλλος = clay). Argillaceous components are fine-grained (less than 2 μm) aluminosilicates, and more particularly clay minerals such as kaolinite, montmorillonite-smectite, illite, and chlorite. Claystone and shales[1] are thus predominantly argillaceous. Argillaceous minerals may appear silvery upon optical reflection.
The adjective "argillaceous" is also used to define rocks in which clay minerals are a secondary but significant component.[2] For example, argillaceous limestones are limestones[3] consisting predominantly of calcium carbonate, but including 10-40% of clay minerals: such limestones, when soft, are often called marls. Similarly, argillaceous sandstones are sandstones consisting primarily of quartz grains, with the interstitial spaces filled with clay minerals.
See also
References
- ^ Xiang-Rong, Yang; De-Tian, Yan; Xiao-Song, Wei; Li-Wei, Zhang; Bao, Zhang; Han-Wen, Xu; Yin, Gong; Jie, He (2018-06-01). "Different formation mechanism of quartz in siliceous and argillaceous shales: A case study of Longmaxi Formation in South China". Marine and Petroleum Geology. 94: 80–94. doi:10.1016/j.marpetgeo.2018.03.036. ISSN 0264-8172.
- ^ Siever, Raymond (2019). "Argillaceous rocks". Access Science. doi:10.1036/1097-8542.049900.
- ^ "Argillaceous limestone: Mineral information, data and localities". www.mindat.org. Retrieved 2019-12-27.