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首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Along-strike variations in the thermal and tectonic response of the continental Ecuadorian Andes to the collision with heterogeneous oceanic crust
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Along-strike variations in the thermal and tectonic response of the continental Ecuadorian Andes to the collision with heterogeneous oceanic crust

机译：厄瓜多尔大陆安第斯山脉对与非均质洋壳碰撞的热和构造响应的沿走向变化

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摘要

Oblique to strike geological segmentation in the Andean chain has been previously recognised at various scales and is commonly attributed to changes in the convergence vectors of the oceanic and continental plates, as well as the upper-plate expressions of differing along-strike subducted slab age, strength and composition. We present new white mica and biotite ~(40)Ar/~(39)Ar and zircon and apatite fission-track data from several traverses across the Cordillera Real of Ecuador in the northern Andes that reveal distinct along-strike differences in the timing of accelerated crustal cooling during the Cenozoic. The data record elevated cooling rates from temperatures of ～380 ℃ during ～65-55 and ～43-30 Ma from all sampled regions of the Cordillera Real and at ～15 Ma and since ～9 Ma in the northern Cordillera Real. Each cooling period was probably driven by exhumation in response to the accretion and subduction of heterogeneous oceanic crust. Elevated cooling rates of up to ～30-20 250L?Myr were initiated during the Palaeocene and Eocene-early Oligocene along the entire contemporaneous margin of Ecuador and were driven by the accretion of the oceanic Pallatanga Terrane and Pinon-Macuchi Block, respectively, onto northwestern South America. Both of these geological provinces originated at the southern parts of the leading and trailing boundaries of the Caribbean Plateau and accreted onto the margin during the approximately northeastward migration of the Plateau into its current position. Within Ecuador the development of higher topography and elevated cooling rates of up to 50 ℃/Myr at ～15 Ma and since ～9 Ma are restricted to the region north of 1°30'S and is situated above the postulated subducted flatslab section of the aseismic Carnegie Ridge. Plate convergence rate calculations suggest the Carnegie Ridge collided with the Ecuador Trench at ～15 Ma, which caused the pre-existing coastal provinces to displace to the northeast, subsequently driving extension and marine ingression in southern Ecuador and compression and uplift in northern Ecuador.
机译：斜向走向的安第斯链断裂地质分割先前已在各种尺度上得到认可，通常归因于海洋和大陆板块的收敛矢量的变化，以及沿走板俯冲板片年龄不同的上板块表达，力量和成分。我们提供了来自安第斯山脉北部厄瓜多尔皇家山脉的几次穿越的新白云母和黑云母〜（40）Ar /〜（39）Ar和锆石和磷灰石裂变径迹数据，揭示了不同的沿走时差异。新生代加速了地壳冷却。数据记录了在山脉中心的所有采样区域中，在〜65-55和〜43-30 Ma内，从〜380℃的温度升高的冷却速率，以及在北部山脉的〜15 Ma和〜9 Ma以来的冷却速率。每个冷却期可能是由于对异质海洋地壳积聚和俯冲的挖掘而导致的。在古新世和始新世早期渐新世期间，厄瓜多尔的整个同时期开始使冷却速率提高到约30-20250L？Myr，这分别是由海洋Pallatanga Terrane和Pinon-Macuchi块体的积聚驱动的，到南美西北部。这两个地质省份都起源于加勒比高原前缘和后缘的南部，并在高原向东北方向向其当前位置的大约东北迁移期间向边缘扩散。在厄瓜多尔内部，较高的地形和〜15 Ma的最高冷却速度高达50℃/ Myr，并且由于〜9 Ma仅限于南北1°30的区域，并且位于抗震卡内基的假定俯冲平板区域之上岭。板块收敛速度的计算表明，卡内基山脊在约15 Ma处与厄瓜多尔海沟相撞，这导致先前存在的沿海省份向东北移动，继而推动了厄瓜多尔南部的扩张和海侵，以及厄瓜多尔北部的压缩和隆升。

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