-
43浏览
-
0点赞
-
0收藏
-
0分享
-
48下载
-
0评论
-
引用
期刊论文
Seismic multi-Arch structures in East China
Science in China, 2005, 48(2),-0001,():
In previous papers, the author has analyzed the deep seismic reflection profiles along some of the Mesozoic plutons in East China, and has pointed out that the crustal structures around these intrusions usually correlate with a special seismic fabric called the seismic multi-arch structure [1]. This paper continues to show main characteristics of the seismic multi-arch structures and discuss their relationship with mantle-origin magmatism and the lithospheric thinning process. Calibration of seismic reflectors in Chinese continental drilling sites shows that small-scale arch-like reflectors can be generated by fractured eclogites or other plutons; they do not belong to the multi-arch structure specially discussed in the paper. The multi-arch structure is characterized by several arch-like reflectors distributed in both the upper and lower crust with granitoid plutons or stocks exposed on the surface, which do not have obvious negative Europium anomalies. Based on the distribution pattern of arch reflectors, the seismic multi-arch structures can be divided into three main types, namely the simple vertical combination type, the spread arch type and the arch-bouquet type. All of them correlate to mantle-origin magmatism, but occur in different regional locations. The spread arch structures occur within a Mesozoic/Cenozoic rift zone with very thin and hot lithosphere. The vertical combination type of the multi-arch structures occurs near the rift zones where lithosphere was thin and hot. The arch-bouquet structures occur far from the rift zones where the lithosphere is not hot. The continental rifting that acted as the latest episode of a lithospheric thinning process usually coincides with the thinnest part of the lithosphere in East China. In different locations within the lithospheric thinning areas, mantle-origin magmatic activities have different patterns, which might generate different types of crustal structures revealed by the different types of the multi-arch structures. Therefore, high-quality deep seismic reflection profiles can be used indirectly to identify the patterns and scales of Mesozoic/Cenozoic lithospheric thinning processes, as well as characteristics of the corresponding mantle-origin magmatic activities.
【免责声明】以下全部内容由[杨文采]上传于[2007年09月19日 16时21分03秒],版权归原创者所有。本文仅代表作者本人观点,与本网站无关。本网站对文中陈述、观点判断保持中立,不对所包含内容的准确性、可靠性或完整性提供任何明示或暗示的保证。请读者仅作参考,并请自行承担全部责任。
本学者其他成果
同领域成果