Tectonics of the Eastern GhaLs Mobile Belt of India -Study of Proterozoic Events in EasL Gondwana-

印度东部GhaLs活动带的构造-EasL Gondwana元古代事件研究-

• 批准号: 08041109
• 负责人: YOSHIDA Masaru
• 金额: $ 6.34万
• 依托单位: Osaka City University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08041109/
• 关键词: Indian Shield; Eastern Ghats Mobile Belt; Granulite; Proterozoic; Sri Lankan granulites; Gondwanaland; Kerala Khodalite Belt; Calc-silicate granulite; グラファイト

Field based geological studies of Eastern Ghats, South India and Sri Lanka were conducted. Major results are as follows which appeared in 101 scientific publications.(1) Sm-Nd and Rb-Sr ages, and U-Pb isotopic and U-Th-Pb chemical ages of monazite and zircon were obtained. Circa 2500 and 2000 Ma of the precursory rocks, ca 1500, 1000, 700-800, and 500 Ma ages of repeated tectonothermal events were obtained.(2) Small scale rootless isoclinals folds and sheath folds proceeding the major isoclinals folds were identified in the central Eastern Gahts Mobile Belt.(3) Corundum-quartz assemblage were discovered in the metapelite from the central Eastern Ghats Mobile Belt. The metapelite suffered higher conditions than ca 13 Kb and 1150℃, and then drastic isothermal decompression to ca 9 kb and 950℃, followed by isosbaric cooling then isothermal decompression.(4) The polymetamorphic history of the Eastern Ghats Mobile Belt identified from the present study suggests that the juxtaposition with the Rayner Complex of Antarctica vas later than ca 1500 Na, and most possibly during the ca 1000 Ka event.(5) The Achankovil Shear Zone of South India vas found to have suffered the sinistral shear, at least in its central portion.(6) Petrological studies of granulites in central Sri Lanka and calc-silicate rocks and alkaline acid intrusive in South India, and tectonic studies of Precambrian East Gondwanaland were also examined.

对东高止山脉、南印度和斯里兰卡进行了实地地质研究。主要结果如下，发表在101份科学出版物上。(1)获得了独居石和锆石的Sm-Nd和Rb-Sr年龄、U-Pb同位素和U-Th-Pb化学年龄。获得了约2500和2000 Ma的岩浆岩和约1500、1000、700-800和500 Ma的重复构造事件年龄。(2)在中东部的Gahts移动的带中发现了小规模的无根等倾褶皱和鞘褶皱，它们是主要等倾褶皱的延续。(3)在东高止山脉移动的带中部的变岩中发现了刚玉-石英组合。变岩经历了高于约13 Kb和1150℃的条件，然后急剧等温减压至约9 Kb和950℃，然后等压冷却，然后等温减压。(4)东高止山脉移动的带的多变质历史表明，与南极洲Rayner杂岩的并置时间晚于约1500 Na，最有可能发生在约1000 Ka事件期间。(5)南印度Achankovil剪切带至少在其中部遭受左旋剪切。(6)对斯里兰卡中部麻粒岩、南印度钙硅酸盐岩和碱性酸性侵入岩的岩石学研究以及前寒武纪东冈瓦纳大陆的构造研究也进行了审查。

项目成果

Rao, A.T.et al.: "Geochemical signatures of calc-silicates and carbonate rocks from Borra area in the Eastern Ghats Ganulite Belt." Gondwana Research Group Memoir. No.4(印刷中). (1998)

Rao, A.T. 等人：“东高止山脉冈努岩带博拉地区钙硅酸盐和碳酸盐岩石的地球化学特征”，冈瓦纳研究小组回忆录第 4 期（1998 年）。

Yoshida, Masaru and Arima, M.: "Proterozoic events in East Gondwana : Japanese contribution to IGCP-368." Japan Contribution ot IGCP, 1996. Japan Committee of IGCP, Tokyo. 73-83 (1996)

Yoshida, Masaru 和 Arima, M.：“东冈瓦纳元古代事件：日本对 IGCP-368 的贡献”。

Rajesh, H. M. and Santosh, M.: "Alkaline magmatism in Peninslar India." Gondwana Research Group Memoir 3 "The Archaean and Proterozoic Terrains of Southen India, Text book and Field Guide". Field Science Pub. , Osaka. 91-115 (1996)

Rajesh, H. M. 和 Santosh, M.：“印度半岛的碱性岩浆作用。”

Chandran, R. R. et al.: "Proterozoic mineralization in southern Kerala : summary characteristics and genesis." Gondwana Research Group Memoir 3 "The Archaean and Proterozoic Terrains of Southen India, Text book and Field Guide". Field Science Pub. , Osaka

Chandran, R. R. 等人：“喀拉拉邦南部元古代矿化：总结特征和成因。”

Tani, Yasutaka and Yoshida, M.: "Strctural evolution of the Arena Gneiss and its bearing on the Proterozoic tectonics of Sri Lanka." Jour. Southeast Asian Earth Sciences. 14, 3-4. 309-329 (1996)

Tani, Yasutaka 和 Yoshida, M.：“竞技场片麻岩的结构演化及其对斯里兰卡元古代构造的影响。”