在美国加利福尼亚州内华达山脉南部下方发现的岩石圈下沉现象。

Foundering lithosphere imaged beneath the southern Sierra Nevada, California, USA.

作者信息

Boyd Oliver S, Jones Craig H, Sheehan Anne F

机构信息

Department of Geological Sciences, University of Colorado at Boulder, 2200 Colorado Avenue, Boulder, CO 80309-0399, USA.

出版信息

Science. 2004 Jul 30;305(5684):660-2. doi: 10.1126/science.1099181.

DOI:10.1126/science.1099181

PMID:15286370

Abstract

Seismic tomography reveals garnet-rich crust and mantle lithosphere descending into the upper mantle beneath the southeastern Sierra Nevada. The descending lithosphere consists of two layers: an iron-rich eclogite above a magnesium-rich garnet peridotite. These results place descending eclogite above and east of high P wave speed material previously imaged beneath the southern Great Valley, suggesting a previously unsuspected coherence in the lithospheric removal process.

摘要

地震层析成像显示，富含石榴石的地壳和岩石圈地幔正在内华达山脉东南部下方俯冲到上地幔中。俯冲的岩石圈由两层组成：富含铁的榴辉岩位于富含镁的石榴石橄榄岩之上。这些结果表明，俯冲的榴辉岩位于此前在大谷地南部下方成像的高P波速度物质之上和东部，这表明在岩石圈移除过程中存在此前未被怀疑的连贯性。