Study on Paleomagnetism and Plate Tectonics of Indian Plate

印度板块古地磁与板块构造研究

基本信息

批准号：
04041051
负责人：
HIROOKA Kimio
金额：
$ 6.72万
依托单位：
Toyama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

The aim of this survey is to clarify the paleogeographic position of the Indian subcontinent in the Gondwana super-continent, especially relative position to the Antarctica, and to trace its change of the position with time by the paleomagnetic studies of the eastern regions of the Indian Peninsula along the coast of the Bengal Bay.As a reconnaissance survey, the paleomagnetic and geophysical rock samples were obtained from various rock formations in the region of the Godavari and the Mahanadi Grabens in 1991. The preliminary paleomagnetic measurements of the samples show that most of the rocks of old ages such as Archean and Proterozoic have very complex multiple remanent components. So that, the paleomagnetic samplings were concentrated to the rocks of the trap basalt and the Gondwana sediments of the Paleozoic and Mesozoic in 1992 and 1993. Rock samples were collected from 35 sites in 1992 and from 24 sites in 1993 in the regions of Rajimahal hills, the Mahanadi Graben, the Godavari Graben and the Tamil-Nadu.Although the paleomagnetic and age dating studies are still on going, we got some preliminary results. 6 ages are determined by the Ar-Ar method. The ages obtained are 574 Ma for the Archean dike of Site 21, 520 Ma for the lower Proterozoic khondalite of Site 34, 510-520 Ma for the Proterozoic dolerite dike of Site 0, and 510 Ma for the Proterozoic gneissose granite of Site 1 in the Godavari graben, and 560 and 680 Ma for the Archean granitic gneiss of Site 38 and 59, in the Mahanadi Graben. And 6 reliable paleomagnetic remanent directions are obtained from the Archean granitic gneiss of Site 38, the Archean charnokite of Site 39, the Proterozoic dolerite dike of Site 0, and the Cretaceous Rajmahl trap basalt flows of Sites 80, 82 and 101.

这项调查的目的是阐明印度次大陆在冈瓦纳次大陆中的古地理位置，尤其是与南极的相对位置，并通过对印度半岛东部地区的西部地区沿孟加拉湾沿海地区的沿海地区的各种岩石造型的岩石造型的岩石造型，众多岩石造型的岩石造型，并追踪其随时间的变化。 Godavari和Mahanadi于1991年抓住。样品的初步古磁测量表明，大多数老年岩石（例如Archean and Proterorokoic）具有非常复杂的多重remanent组件。因此，将古磁采样集中在1992年和1993年的古生代和中生代的陷阱岩石和冈瓦纳沉积物中。1992年从35个地点收集了岩石样品，并从1993年的24个地点收集了Rajimahal Hills the Mahanadi Graben and godamir and godamir and the godamir and the godamir and the godamir and the godamir and the godamir and the godamir and。古磁和年龄约会研究仍在进行中，我们获得了一些初步结果。 6个年龄由AR-AR方法确定。位点21、520 mA的大老式堤防获得的年龄为574 ma，用于位点34、510-520 mA的较低的原始水生代kondalite，用于位点0的properoxoic dolerite dike，510 mA，用于Proterorogiac graniss 1 gran和680 MA的proterorogoic gneossose Granite 1的MA，560 MA 59，在马哈纳迪（Mahanadi）抓斗中。和6个可靠的古磁透明方向是从地点38的太古花岗岩片麻岩，位置39的大将charnokite，位置0的proterorocic dolerite dike以及Cretaceous rajmahl捕获量的Basalt Basalt流量80、82和101。