Reconciling plate kinematic and seismic estimates of lithospheric convergence in the central Indian Ocean
Reconciling plate kinematic and seismic estimates of lithospheric convergence in the central Indian Ocean
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DOI：
10.1130/g30521.1
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发表时间：
2010-04-01
期刊：
影响因子：
5.8
通讯作者：
Merkouriev, S.
中科院分区：
文献类型：
--
作者：
Bull, J. M.;DeMets, C.;Merkouriev, S.
印度-亚洲碰撞的远场特征和西藏隆起的历史是通过输入印度洋的沉积物以及跨越印度板块和摩羯座板块之间的扩散板块边界的应变积累历史记录的。我们根据印度-索马里-摩羯座板块旋转的最新估计和地震反射数据的观测来描述印度-摩羯座汇聚的历史。过去 20 年来印度-摩羯座板块的新旋转与 18 Ma 以来围绕查戈斯-拉卡迪夫海岭东缘附近的静止或接近静止极点的缓慢南北向辐合一致，比之前基于更少数据的模型所预测的要简单。新的旋转表明聚合开始于 18 至 14 Ma，这与 15.4-13.9 Ma 开始变形的海洋地震证据一致。他们进一步表明，收敛速度在 8 Ma 时加倍，这与地震反射剖面上看到的 8-7.5 Ma 断层活动急剧增加一致。如果扩散板块边界内普遍存在的反向断层伴随着1度-3度的块体旋转，则根据运动学和地震反射数据估计的总应变之间的差异可以得到调节。
The far-field signature of the India-Asia collision and history of uplift in Tibet are recorded by sediment input into the Indian Ocean and the strain accumulation history across the diffuse plate boundary between the Indian and Capricorn plates. We describe the history of India-Capricorn convergence from updated estimates of India-Somalia-Capricorn plate rotations and observations derived from seismic reflection data. New India-Capricorn plate rotations for the past 20 m.y. are consistent with slow north-south convergence from 18 Ma about a stationary or nearly stationary pole near the eastern edge of the Chagos-Laccadive ridge, simpler than predicted by previous models based on many fewer data. The new rotations suggest that convergence began between 18 and 14 Ma, consistent with marine seismic evidence for an onset of deformation at 15.4-13.9 Ma. They further show that convergence rates doubled at 8 Ma, in agreement with a sharp increase in fault activity at 8-7.5 Ma seen on seismic reflection profiles. A discrepancy between the total strain estimated from kinematic and seismic reflection data can be reconciled if pervasive reverse faulting within the diffuse plate boundary is accompanied by block rotations of 1 degrees-3 degrees.