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Laterite occurs extensively over the crystalline and sedimentary rocks in the midland and lowland areas of south Kerala, India. Two lateritization cycles are identified in this area. Large, good-quality kaolin deposits, composed mostly of kaolinite, are characteristic of the sedimentary sequence in south Kerala. These deposits were formed on deposition of the weathering materials of the khondalites towards the first cycle of lateritization. After deposition and uplift of the sedimentary rocks, another lateritization cycle affected these, as well as the khondalites during pre-Quaternary times with the formation of a planation surface at 25–125 m above sea level having thick laterite profiles. The laterite profiles over the kaolin deposits show higher concentration of Fe-oxides (mostly in the form of hematite) and titania, compared to their concentration in the kaolins. Higher contents of Cr and Ni are also characteristic of the laterite over kaolin deposits. Recrystallization of the kaolinite, appearance of Al, Fe and Si amorphous phases in the kaolin clays and partial removal of Fe and Ti from them are attributed to the second lateritization cycle. 相似文献
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Mamedov V. I. Shipilova E. S. Boeva N. M. Slukin A. D. Makarova M. A. Vnuchkov D. A. Bortnikov N. S. 《Doklady Earth Sciences》2020,490(1):8-12
Doklady Earth Sciences - Investigation of the comprehensive geological material on the lateritic weathering rocks (Futa Jallon-Mandingo, Africa) led to original identification of a specific horizon... 相似文献
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N. S. Bortnikov Yu. Yu. Bugel’sky A. D. Slukin V. M. Novikov G. O. Piloyan 《Geology of Ore Deposits》2011,53(6):435-446
The theory of ore-bearing weathering mantles (WM) was developed at the Institute of Geological Sciences, USSR Academy of Sciences
(currently the Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry, Russian Academy of Sciences)
in the 1930s. I.I. Ginzburg was an originator of this theory. The extensive new data on the bauxite-, Ni-, Au-, REE-bearing
and other rare-metal WM has led to the development of a general theory of exogenic ore deposits, which has been confirmed
by forecasting, prospecting, and exploration of solid mineral resources. On considering the current status of the WM theory
based on the results of precision research methods (XRD, IRS, EPR spectroscopy, DTA, electron microscopy, etc.), the main
aspects determining its advance can be pointed out: (1) physicochemical simulation of WM formation; (2) identification and
study of nanominerals in WM; (3) study of the contribution of organic matter to weathering; and (4) use of WM as indicators
of climatic change in the Earth’s history. As is presently established, WM are natural chemical reactors of nanoparticles
of various minerals. The progress in nanomineralogy of WM will facilitate the choice of rational methods of mining and recovery
of valuable components. As has been proved by electron microscopy, fossilized microbial communities, biofilms, and cyanobacterial
mats occur in almost all WM. The importance of studying mutual relations of inorganic and organic substances of WM in more
detail is evident. Development of the idea of using WM as indicators of paleoclimate will provide insights into global changes
in the environment and complement the results obtained by traditional paleoclimatic methods. This aspect is especially topical
in connection with widely discussed problem of global climatic warming. 相似文献
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Boeva N. M. Makarova M. A. Shipilova E. S. Slukin A. D. Soboleva S. V. Zhegallo E. A. Zaitseva L. V. Bortnikov N. S. 《Doklady Earth Sciences》2022,504(2):353-361
Doklady Earth Sciences - The main source of aluminum is bauxite ores and their basic mineral components gibbsite Al(OH)3 and boehmite AlO(OH). Alumina Al2O3 is formed by various methods of... 相似文献
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Boeva N. M. Makarova M. A. Shipilova E. S. Slukin A. D. Melnikov F. P. Karimova O. V. Bortnikov N. S. 《Doklady Earth Sciences》2022,507(1):871-880
Doklady Earth Sciences - The Central bauxite deposit on the territory of the Russian Federation is a unique geological object. It hosts both primary lateritic bauxites and products of their... 相似文献
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Mamedov V. I. Makarova M. A. Boeva N. M. Slukin A. D. Shipilova E. S. Bortnikov N. S. 《Doklady Earth Sciences》2020,492(1):291-296
Doklady Earth Sciences - In the course of additional exploration of the lower horizons of the unique Sangaredi deposit in West Africa, nonlaterized deposits of the Sangaredi series of all major... 相似文献
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Boeva N. M. Slukin A. D. Shipilova E. S. Makarova M. A. Balashov F. V. Zhegallo E. A. Zaytseva L. V. Bortnikov N. S. 《Doklady Earth Sciences》2021,500(1):720-727
Doklady Earth Sciences - The mineral and chemical composition of bauxites from the Chadobets uplift of the Siberian Platform is the total product of laterites on aluminosilicate rocks (source of... 相似文献