Study on Paleomagnetism and Plate Tectonics of Indian Plate

本次调查的目的是通过对哥达瓦里地堑和马哈纳迪地堑古地磁的研究，阐明印度半岛与其他大陆块体，特别是与南极洲的相对古地磁位置及其随时间的变化。在这些地堑中不仅分布着中生代冈瓦纳沉积，还分布着太古宙和元古代基底岩。我们与本次调查对应的印度地质调查局（GSI）进行了讨论，并确认此次调查将作为印度-日本科学合作计划进行推广，部分支持国际地质对比计划（IGCP）。288.实地调查首先于10月21日至29日在Godavari地区进行，与GSI海得拉巴合作，然后于10月31日至11月5日在Mahanadi地区进行，与GSI布巴内斯瓦尔和加尔各答合作。由于这一建议被接受为1991年的一年侦察调查，我们尽量在两个地区收集尽可能多的岩石，以排除适合古地磁测量的岩石。通过野外取样，我们获得了56个测点的501个定向古地磁样品。样品的岩石种类有砂岩、粉砂岩、灰岩、白云岩、玄武岩、白云岩脉、花岗岩、伟晶岩、混辉岩、片麻岩花岗岩、孔雀岩、黑钙岩、石英、片岩、菲利岩等。

The aim of this survey is to clarify the relative paleoposition of the Indian Peninsula to the other continental masses, especially to the Antarctica, and its change with time by the study of paleomagnetism at the Godavari and the Mahanadi Grabens. Not only the Gondwana sediments of the Mesozoic the Archean and the Proterozoic basement rock are distributed at these grabens.We discussed with the Geological Survey of India (GSI) who are the counterpart of this survey, and confirmed that this survey is promoted as an India-Japan scientific cooperative program partly supporting the International Geological correlation Program (IGCP) no. 288.The field survey was undergone first in the Godavari region from 21st through 29th, October, with the collaboration of GSI Hyderabad, and then in the Mahanadi region from 31st, October through 5th, November with cooperation of GSI Bhubaneswar and Calcutta.Since this proposal is accepted as a one year reconnaissance survey for 1991, we tried to collect as many kinds of rocks as possible in both of the regions to eliminate what kind of rocks is suitable for paleomagnetic measurements.As the result of field sampling, we obtained 501 oriented paleomagnetic samples from 56 sites. Rock kinds of the samples are sandstone, siltstone, limestone, dolomite, basalt, dolerite dyke, granite, pegmatite, migmatite, gneissose granite, khondalite, chernockite, quatzite, schist and phillite.