Pusok Adina E, Stegman Dave R
Scripps Institution of Oceanography, UC San Diego, La Jolla, CA, USA.
Sci Adv. 2020 May 6;6(19):eaaz8681. doi: 10.1126/sciadv.aaz8681. eCollection 2020 May.
During the Cretaceous, the Indian plate moved towards Eurasia at the fastest rates ever recorded. The details of this journey are preserved in the Indian Ocean seafloor, which document two distinct pulses of fast motion, separated by a noticeable slowdown. The nature of this rapid acceleration, followed by a rapid slowdown and then succeeded by a second speedup, is puzzling to explain. Using an extensive observation dataset and numerical models of subduction, we show that the arrival of the Reunion mantle plume started a sequence of events that can explain this history of plate motion. The forces applied by the plume initiate an intra-oceanic subduction zone, which eventually adds enough additional force to drive the plates at the anomalously fast speeds. The two-stage closure of a double subduction system, including accretion of an island arc at 50 million years ago, may help reconcile geological evidence for a protracted India-Eurasia collision.
在白垩纪时期，印度板块以有记录以来的最快速度向欧亚大陆移动。这段移动历程的细节保存在印度洋海底，记录了两次明显的快速移动脉冲，中间有一段显著的减速期。这种先快速加速、接着快速减速、然后再次加速的现象，其成因令人费解。通过使用广泛的观测数据集和俯冲作用的数值模型，我们发现留尼汪地幔柱的到来引发了一系列事件，能够解释这段板块运动历史。地幔柱施加的力引发了一个大洋内俯冲带，最终增加了足够的额外力量，驱使板块以异常快的速度移动。一个双俯冲系统的两阶段闭合，包括在5000万年前一个岛弧的增生，可能有助于协调印度-欧亚大陆长期碰撞的地质证据。
