Timing of Eocene compressional plate failure during subduction initiation, northern Zealandia, southwestern Pacific
Timing of Eocene compressional plate failure during subduction initiation, northern Zealandia, southwestern Pacific
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DOI：
10.1093/gji/ggac016
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发表时间：
2022-01
影响因子：
2.8
通讯作者：
W. Stratford;R. Sutherland;G. Dickens;P. Blum;J. Collot;M. Gurnis;S. Saito;A. BordenaveG;S. Etienne;C. Agnini;L. Alegret;G. Asatryan;J. Bhattacharya;L. Chang;M. Cramwinckel;E. Dallanave;M. Drake;M. Giorgioni;D. Harper;H.-H. M. Huang-H.;A. Keller;A. Lam;H. Li;H. Matsui;H. Morgans;C. Newsam;Y. Park;K. Pascher;S. Pekar;D. Penman;T. Westerhold;X. Zhou
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文献类型：
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作者：
W. Stratford;R. Sutherland;G. Dickens;P. Blum;J. Collot;M. Gurnis;S. Saito;A. BordenaveG;S. Etienne;C. Agnini;L. Alegret;G. Asatryan;J. Bhattacharya;L. Chang;M. Cramwinckel;E. Dallanave;M. Drake;M. Giorgioni;D. Harper;H.-H. M. Huang-H.;A. Keller;A. Lam;H. Li;H. Matsui;H. Morgans;C. Newsam;Y. Park;K. Pascher;S. Pekar;D. Penman;T. Westerhold;X. Zhou
在始新世早期，西太平洋辐合边缘俯冲构造的快速爆发，随后在始新世中期，西兰迪亚北部的原汤加-克马德克俯冲系统的边缘生长缓慢。我们提出了来自国际海洋发现计划远征371的新西兰北部沉积物变形事件钻孔数据的新时代约束，这些数据记录了新西兰西北部辐合边缘边界的形成。形变显示了一个持续时间长达20myr的缩短事件，并在新西兰西北部不断发展的板块边缘内侧约1000公里的距离上发生作用。与我们的新钻孔地点相关联的多通道地震剖面显示，缩短主要发生在45 Ma和35 Ma之间，一些与边坡破坏有关的变形持续到渐新世。缩短的终止与西南太平洋弧后盆地的打开和汤加-克马德克海沟的东移有关，这可能消除了始新世板块边缘的构造证据。在演化中的原汤加-克马德克俯冲系统内部观测到的古近纪变形表明，西兰迪亚北部是一个薄大陆地壳区域，其岩石圈足够强大，可以作为应力导向。在开始的俯冲系统之后，挤压应力引起了板块内褶皱和断裂，有限的变形期表明西兰洲北缘有一个活动的辐合边缘。
Rapid onset of subduction tectonics across the western Pacific convergent margins in the early Eocene was followed by a slower phase of margin growth of the proto Tonga-Kermadec subduction system north of Zealandia during a middle Eocene phase to tectonic adjustment. We present new age constraints from International Ocean Discovery Program Expedition 371 borehole data on deformation events in northern Zealandian sediments that document the formation of the convergent margin boundary northwest of New Zealand. The deformation shows a shortening event that lasted up to 20 myr and acted over distances of ∼1000 km inboard of the evolving plate margin, just northwest of New Zealand. Multichannel seismic profiles tied to our new borehole sites show shortening occurred predominantly between 45 Ma and 35 Ma with some deformation related to slope failure continuing into the Oligocene. The termination of shortening is linked to opening of the backarc basins of the southwest Pacific and the migration of the Tonga-Kermadec Trench to the east which may have removed the structural evidence of the Eocene plate margin. Paleogene deformation observed inboard of the evolving proto Tonga-Kermadec subduction system indicates that the lithosphere of northern Zealandia, a region of thin continental crust, was strong enough to act as a stress guide. Compressive stresses that caused intra plate folding and faulting developed behind the initiating subduction system with the finite period of deformation indicating the time frame over which an active convergent margin lay along the northern margin of Zealandia.