Kinematics and dynamics of the East Pacific Rise linked to a stable, deep-mantle upwelling.
Kinematics and dynamics of the East Pacific Rise linked to a stable, deep-mantle upwelling.
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DOI：
10.1126/sciadv.1601107
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发表时间：
2016-12
期刊：
影响因子：
13.6
通讯作者：
Simmons NA
中科院分区：
文献类型：
--
作者：
Rowley DB;Forte AM;Rowan CJ;Glišović P;Moucha R;Grand SP;Simmons NA
东太平洋海隆的纵向稳定性反映了地幔浮力、地幔流和海底扩张的耦合作用。地球的构造板块通常被认为主要是由与大洋岩石圈俯冲有关的负浮力驱动的。在这种情况下，洋中脊（MORs）是被动的板块边界，其发散容纳由海沟处的大洋板块俯冲驱动的流动。我们发现，在过去的8000万年（我），东太平洋海隆（EPR），地球的主要莫尔，其特点是有限的脊垂直迁移和持久的，不对称的脊吸积是异常的相对于其他MORs。我们重建的EPR两侧的板块俯冲相关的浮力通量。一般的预期是，更大的板块拉力应该与更快的板块运动和更快的扩张在EPR。此外，在EPR两侧的板拉的不对称性应与脊迁移或在更大的板拉的方向上增强的板块速度相关。根据我们的分析，预期的相关性都不明显。这意味着，其他力量显着贡献EPR行为。我们解释这些意见使用地幔流计算的基础上，全球一体化的浮力分布，需要核幔边界热通量高达20 TW。随时间变化的地幔流预测产生一个长期存在的深部上升流，具有最高的径向速度下的EPR和推断控制其观察到的运动学。EPR下的地幔范围内的上涌驱动水平分量的软流层流动的板块下，同样是不对称的，但速度比上覆的表面板块，从而有助于通过在太平洋地区的粘性牵引板块运动。
Longitudinal stability of East Pacific Rise reflects coupling of deep-mantle buoyancy, mantle-wide flow, and seafloor spreading. Earth’s tectonic plates are generally considered to be driven largely by negative buoyancy associated with subduction of oceanic lithosphere. In this context, mid-ocean ridges (MORs) are passive plate boundaries whose divergence accommodates flow driven by subduction of oceanic slabs at trenches. We show that over the past 80 million years (My), the East Pacific Rise (EPR), Earth’s dominant MOR, has been characterized by limited ridge-perpendicular migration and persistent, asymmetric ridge accretion that are anomalous relative to other MORs. We reconstruct the subduction-related buoyancy fluxes of plates on either side of the EPR. The general expectation is that greater slab pull should correlate with faster plate motion and faster spreading at the EPR. Moreover, asymmetry in slab pull on either side of the EPR should correlate with either ridge migration or enhanced plate velocity in the direction of greater slab pull. Based on our analysis, none of the expected correlations are evident. This implies that other forces significantly contribute to EPR behavior. We explain these observations using mantle flow calculations based on globally integrated buoyancy distributions that require core-mantle boundary heat flux of up to 20 TW. The time-dependent mantle flow predictions yield a long-lived deep-seated upwelling that has its highest radial velocity under the EPR and is inferred to control its observed kinematics. The mantle-wide upwelling beneath the EPR drives horizontal components of asthenospheric flows beneath the plates that are similarly asymmetric but faster than the overlying surface plates, thereby contributing to plate motions through viscous tractions in the Pacific region.
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影响因子：
5.3
作者：
Gaina, C;Roest, WR;Müller, RD
通讯作者：
Müller, RD
影响因子：
5.8
作者：
Bull, J. M.;DeMets, C.;Merkouriev, S.
通讯作者：
Merkouriev, S.
影响因子：
5.3
作者：
Forte, Alessandro M.;Quere, Sandrine;Rowley, David B.
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Rowley, David B.
影响因子：
5.3
作者：
Behn, MD;Conrad, CP;Silver, PG
通讯作者：
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影响因子：
3.5
作者：
Conrad, Clinton P.;Behn, Mark D.
通讯作者：
Behn, Mark D.