Kaolinization


Also found in: Dictionary, Wikipedia.

kaolinization

[‚kā·ə·lə·nə′zā·shən]
(geology)
The forming of kaolin by the weathering of aluminum silicate minerals or other clay minerals.

Kaolinization

 

rock alteration leading to the formation of kaolin by the transformation of various minerals containing alumina, and, above all, of feldspars and mica. Kaolinization is most strongly manifested in the formation of a kaolin weathering mantle as a result of weathering in granites, syenites, and other feldspathic rock, evidently under humid, subtropical conditions. In this process a finely flaked, alumina-rich mica is initially formed from the feldspar. This mica is called sericite, and subsequently it becomes hydrated and is converted into hydromica and kaolinite. Remnants of hydromica are often present among the kaolinites that have formed as a result of kaolinization. Kaolinization processes are also manifested when there is perisurface hydrothermal alteration of rock in areas of volcanic activity.

Intensive processes of rock kaolinization and the formation ofweathering mantles occurred during the Carboniferous, Jurassic, Paleogene, and Neocene periods, which were characterized byabundant vegetation and a relatively humid and warm climate. Modern kaolinization is most characteristic in the humid tropics.

Mentioned in ?
References in periodicals archive ?
Incomplete kaolinization indicates lesser amount of kaolin minerals, and thus lowers Al2O3 content (Sayin, 2007; Visser and Young, 1990).
In the depth range of 2800-3200 m, kaolinization of K-feldspars and dissolution of metamorphic lithic fragments led to concentration of [K.sup.+], [Fe.sup.2+], and [Mg.sup.2+] in pore fluids.
(a) kaolinite sample from Karlovy Vary region, formed by kaolinization of granite (Jimlikov u Chodova locality)
Its white color is due to intense kaolinization of feldspar.
In order that the alteration of parent silicates would reach up to the kaolinization or finally the lateritization (gibbsite, boehmite, diaspore), large volumes of water with desirable concentration of protons must percolate the rock.
In most of the best deposits, intense kaolinization of the feldspars and abundant lithium mineralization is common.
From inside out, this zoning includes a potassic alteration zone, a quartz-sericitization zone, a kaolinization zone, and a porphyritic zone (chloritization, epidotization, and carbonate alteration assemblages).
(1968): Magmatic quartz as an indicator of kaolinization of granite rocks.
The highly intruded condition of the hanging wall has resulted in extensive kaolinization which has widened the mineralized vein to a total thickness of 10 feet in some places (Pratt, 1938).
According to their model, meteoric water flux results in the rapid generation of "nutrient" ions ([Al.sup.3+], [Si.sup.4+]) for kaolinization through the dissolution of unstable detrital grains, such as feldspar and mica; the consequent rapid kaolinite growth then affects the texture of these minerals.
The climatic weathering hypothesis received support from Vachtl and Zemlicka (1959), while Kavka (1977, 1978) prefers kaolinization caused by the volcanothermal interaction between hot phonolite lava and wet lacustrine sediments.