...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Asian earth sciences >Passive source seismic imaging of the crust and upper mantle underlying the Archean Singhbhum Craton, Eastern India
【24h】

Passive source seismic imaging of the crust and upper mantle underlying the Archean Singhbhum Craton, Eastern India

机译：印度东部太古代宙斯邦克拉通底下地壳和上地幔的被动震源成像

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

An improved image of crust-mantle structure has been obtained through the joint inversion of P-to-s receiver functions and fundamental mode group velocity data (7-70 s) of Rayleigh and Love waves at fifteen broadband stations in the Eastern Indian Craton. Our modelling reveals a marked crustal thinning of 5-10 km below the Singhbhum-Odisha-Craton (SOC) while the modelled Moho depths show a flat crust with a thickness of 42 km below the Chotanagpur Granitic Gneissic Terrain (CGGT). The modelled lithosphere is thin (similar to 90 km) beneath the SOC and deepens on both north and south sides to similar to 100 km with a sharp drop of similar to 4.4% in shear velocity across the lithosphere-asthenosphere boundary. The amount of melt required in the asthenosphere to account for this drop in shear velocity is similar to 1%. The isotopic constituents of the Dalma volcanic rocks contains asthenospheric component. We suggest that the modeled crustal and lithospheric thinning might have been resulted from the earlier magmatism or plume episodes that led to lithospheric delamination below the SOC. Our modeling also detects a common elongated feature (extending between latitude 21-23 degrees N and longitude 85-86.4 degrees E), which is characterized by a marked crustal (5-10 km) as well as lithospheric (10-15 km) thinning and a significant drop in Vs (-2.1 to -4.4%) in the upper mantle, below the SOC. This mapped area coincides with the horse-shoe shaped broad Singhbhum synclinorium known as Iron Ore Group (IOG) basin that hosts huge iron ore and to some extent manganese deposits of Precambrian age. This lithospheric feature is inferred to have played a key role in forming the passage for melts to carry various iron rich minerals and metals to the uppermost oceanic crust during the Archean plume associated with magmatism episode.
机译：通过对印度洋东部克拉通的15个宽带站的P-to-s接收器函数和瑞利波和洛夫波的基模群速度数据（7-70 s）进行联合反演，获得了地壳幔结构的改进图像。我们的模型揭示了在Singhbhum-Odisha-Craton（SOC）下5-10 km处明显的地壳变薄，而模型化的Moho深度显示出Chotanagpur花岗岩片麻岩地貌（CGGT）以下42 km的平坦地壳。模拟的岩石圈在SOC之下很薄（大约90 km），在南北两侧都加深到大约100 km，在整个岩石圈-软流圈边界上的剪切速度急剧下降了约4.4％。造成这种剪切速度下降的软流圈所需的熔体量约为1％。达尔马火山岩的同位素组成包含软流圈成分。我们认为，模拟的地壳和岩石圈变薄可能是由于较早的岩浆作用或羽状事件所致，导致岩石圈低于SOC分层。我们的模型还检测到一个常见的细长特征（在北纬21-23度和东经85-86.4度之间延伸），其特征是地壳（5-10公里）和岩石圈（10-15公里）明显变薄SOC下方的上地幔的Vs显着下降（-2.1至-4.4％）。该地图区域与被称为铁矿石集团（IOG）盆地的马蹄形宽阔的Singhbhum斜纹岩层相吻合，该盆地拥有巨大的铁矿石和一定程度的前寒武纪锰矿床。据推测，这种岩石圈特征在形成岩浆通道的过程中起了关键作用，该通道在与岩浆活动有关的太古宙羽流中将各种富含铁的矿物和金属运送到最上层的海洋地壳。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号