3-D Pn tomography reveals continental subduction at the boundaries of the Adriatic microplate in the absence of a precursor oceanic slab
3-D Pn tomography reveals continental subduction at the boundaries of the Adriatic microplate in the absence of a precursor oceanic slab
复制标题
3-D Pn 断层扫描揭示了在没有前体大洋板块的情况下亚得里亚海微板块边界处的大陆俯冲
DOI：
10.1016/j.epsl.2019.01.012
复制
发表时间：
2019-03
影响因子：
5.3
通讯作者：
Fu Li-Yun
中科院分区：
文献类型：
--
作者：
Sun Weijia;Zhao Liang;Malusa Marco G.;Guillot Stephane;Fu Li-Yun
俯冲海洋岩石圈产生的板片拉力通常被认为是大陆俯冲开始的主要触发因素。然而，这可能与没有证据表明海洋岩石圈岩石参与折返循环的超高压地体的出现相矛盾。在这里，我们对地中海中部下方最上地幔 P 速度结构进行了成像，这表明大陆俯冲的启动可能不需要前体大洋板块。我们将 (i) 亚得里亚海微板块的三步倒置 3-D Pn 断层扫描模型与 (ii) 可用的地质约束和非洲-欧亚板块边界带的回弹重建相结合。我们的 Pn 层析成像模型揭示了亚得里亚海微板块周围 Vp < 7.6 km/s 的细长区域，与远震 P 波层析成像推断的板片结构明显相关，并支持沿着第纳里克、高山和亚平宁俯冲带的大陆俯冲。在亚得里亚海微板块的相对两侧观察到了对比鲜明的俯冲类型：在亚平宁山脉下方记录了横向可变的西南倾斜俯冲，北部是大陆性的，南部是海洋性的，那里的回滚速度更快；迪纳里德斯山脉下方记录了横向连续的北东倾大陆俯冲。迪纳里德斯山脉下缺乏前体海洋板片表明，在复杂的板块边界区域，大陆俯冲的开始可以受到远离俯冲起始地点的板块构造过程的控制，并且可能在没有旧海洋岩石圈负浮力的贡献的情况下发生。
Slab pull generated by subducting oceanic lithosphere is generally considered as a major trigger for the onset of continental subduction. However, this may be in conflict with the occurrence of UHP terranes bearing no evidence of oceanic lithospheric rocks involved in the exhumation cycle. Here, we image the uppermost mantle P velocity structure beneath the Central Mediterranean, suggesting the possibility that the initiation of continental subduction may not require a precursor oceanic slab. We combine (i) a three-step inverted 3-D Pn tomography model of the Adriatic microplate with (ii) available geologic constraints and palinspastic reconstructions of the Africa–Eurasia plate-boundary zone. Our Pn tomography model reveals elongated regions with Vp < 7.6 km/s around the Adriatic microplate, clearly connected with the slab structure inferred from teleseismic P wave tomography and supportive of continental subduction along the Dinaric, Alpine and Apenninic subduction zones. Contrasting styles of subduction are observed on the opposite sides of the Adriatic microplate: a laterally variable SW-dipping subduction is documented beneath the Apennines, continental to the north and oceanic to the south, where rollback is faster; a laterally continuous NE-dipping continental subduction is documented under the Dinarides. The lack of a precursor oceanic slab under the Dinarides demonstrates that the onset of continental subduction, in complex plate-boundary zones, can be controlled by plate-tectonic processes far away from the subduction initiation site, and may take place without the contribution of the negative buoyancy of an old oceanic lithosphere.
登录
查看更多内容
影响因子：
2
作者：
Fantoni, R.;Franciosi, R.
通讯作者：
Franciosi, R.
中国东部及周边地区最上地幔P波速结构
影响因子：
2.9
作者：
Sun Weijia;Kennett B. L. N.
通讯作者：
Kennett B. L. N.
影响因子：
2
作者：
M. Sambridge;B. Kennett
通讯作者：
M. Sambridge;B. Kennett
影响因子：
6.1
作者：
M. Malusà;Liang Zhao-;E. Eva;S. Solarino;A. Paul;S. Guillot;S. Schwartz;T. Dumont;C. Aubert;S. Salimbeni;S. Pondrelli;Qingchen Wang;R. Zhu
通讯作者：
M. Malusà;Liang Zhao-;E. Eva;S. Solarino;A. Paul;S. Guillot;S. Schwartz;T. Dumont;C. Aubert;S. Salimbeni;S. Pondrelli;Qingchen Wang;R. Zhu
影响因子：
5.2
作者：
N. Rawlinson;M. Urvoy
通讯作者：
N. Rawlinson;M. Urvoy