东帝汶海槽断裂特征与构造演化模式

Fault characteristics and tectonic evolution model of the East Timor trough

东帝汶海槽位于澳大利亚板块西北帝汶海与帝汶岛之间,晚中新世澳大利亚板块与东南亚班达岛弧碰撞引发了帝汶岛与帝汶海槽的构造变形,由于弧-陆碰撞过程的复杂性,帝汶海槽的变形时间与机制仍然存在较大争议。为约束帝汶海槽变形时间、探讨其演化过程,依据二维地震数据,对东帝汶海槽的断裂特征进行定量分析,并结合钻井与天然地震事件探讨弧-陆碰撞背景下帝汶海槽的构造演化模式。研究结果表明,晚中新世(约6 Ma)澳大利亚板块与班达岛弧碰撞,引发了帝汶岛的隆升与帝汶海槽的沉降,变形持续至晚上新世(约3 Ma),形成现今帝汶海槽形态。现今澳大利亚板块与班达岛弧之间的相对运动速率已逐渐减小趋于停止,未来二者可能会以一个整体继续向北运动。

The East Timor trough is located on the boundary between the Australian plate and the Eurasian plate,whose tectonic deformation was caused by the collision between the Australian plate and the Banda arc in southeastern Asia during Late Miocene.Due to the complexity of the arc-continent collision process,the deformation time and mechanism of the Timor trough are still controversial.In order to limit the deformation time of the Timor trough and discuss its evolution process,the fault characteristics of the Timor trough were quantitatively analyzed based on two-dimensional seismic data,and its tectonic evolution model under the background of arc-land collision was discussed in combination with drilling and natural seismic events.The results show that the Australia plate collided with the Banda island arc in the Late Miocene(about 6 Ma),which triggered the uplifting and subsidence of the Timor trough.The deformation lasted until the Late Pliocene(about 3 Ma),forming the present Timor trough.At present,the relative movement rate between the Australian plate and the Banda island arc has gradually decreased toward a halt.In the future,they may continue to move northward as a whole.