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Clay Mineral and Geochemical Proxies for Intense Climate Change in the Permian Gondwana Rock Record from Eastern India

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Research 2019年第1期2019卷 186-199页

作者： sampa ghosh Joydip Mukhopadhyay Abhijit Chakraborty Department of Geology Presidency University86/1 College StreetKolkata-700073India Department of Geology Jogamaya Devi College92 Shyama Prasad Mukherjee Road700026KolkataIndia

The clay mineral assemblages and geochemical compositions of the Permian Talchir and Barakar mudstones of the Raniganj basin,India,have been used to interpret terrestrial *** Talchir Formation presents unequivocal evidences of the Permian global glacial climate,and the overlying Barakar Formation with braided fluvial deposits immediately follows the glacial amelioration stage to a humid warm *** unaffected by burial diagenesis and originated from a similar source under contrasting climates are ideal for developing proxies for substantial climate ***(28.4-63.8%),illite/smectite(0-58.6%,40-80%illite),chlorite(0-53.9%),and chlorite/smectite(5.6-29.8%)constitute the clay mineral assemblage in the Talchir Formation whereas illite(5.3-78.2%),illite/smectite(trace-34.1%,mostly 60-90%illite),and kaolinite(36.1-86.8%)dominate the clay mineral assemblage in the Barakar *** Talchir mudrocks are enriched in mobile elements and depleted in alumina ***,have relatively higher K_(2)O/Al_(2)O_(3) ratios(~0.3),high ICV(1.12-1.28),and lower CIA values(52.6-65.1)compared to those of the younger Barakar *** Barakar mudstones are depleted in mobile elements ***,have relatively low ICV(0.33-0.62)and K_(2)O/Al_(2)O_(3) values(0.11-0.16),and higher CIA values(72.9-88.2).Textural,mineralogical immaturity,and rock fragments of different components of the basement seen in the Talchir sandstones show these sediments being a first-cycle sedimentary *** distinctive clay mineral assemblage and major oxide composition of the Talchir mudrocks attest to a unique low intensity chemical weathering in cold arid *** presence of kaolinite as well as distinctive geochemical characters of the Barakar mudrocks marks a shift in the paleoclimate from cold arid to *** climatic shift is further supported by the proportion and composition of illite/smectite across the *** relative proportion of chlorite

关键词： Permian mudstone assemblage

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Effect of noise exposure(85 dB) on testicular adrenocortical steroidogenic key enzymes, acid and alkaline phosphatase activities of sex organs in mature albino rats

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Journal of Environmental Sciences 2000年第3期12卷 286-289页

作者： Debidas ghosh, sampa ghosh, Sandip Chattopadhyay, Jogen Debnath (Department of Human Physiology with Community Health, Vidyasagar University, Midnapore\|721 102, West Bengal, India) Department of Human Physiology with Community Health Vidyasagar University Midnapore-721 102 West Bengal India

Changes in the activities of Δ 5\|3β\|hydroysteroid dehydrogenase(HSD) in testis and adrenal gland, 17β\|hydroxysteroid dehydrogenase in testis, acid and alkaline phosphatase in testis, prostate and seminal vesicle were observed in noise exposed mature rats at the intensity of 85 dB for 8 h/day for 45 days. The results indicated that noise exposed group showed a significant diminution in the activities of androgenic key enzymes Δ 5\|3β and 17β\|HSD, acid phosphatase in testis, prostate and seminal vesicle. There was a significant elevation in the activities of adrenal Δ 5\|3β\|HSD, alkaline phosphatase in testis and other accessory sex organ in noise exposed group. Gonadosomatic, prostatosomatic and seminal vesiculo\|somatic indexes were decreased significantly in noise exposed group. Therefore, it is evident that noise exposure at 85dB exerts a deleterious effect on testicular and adrenocortical activities.

关键词： noise hydroxysteroid dehydrogenase acid phosphatase alkaline phosphatase sex organs adrenal cortex

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