The weak and superfast Cretan detachment, Greece: exhumation at subduction rates in extruding wedges
The weak and superfast Cretan detachment, Greece: exhumation at subduction rates in extruding wedges
复制标题
弱而超快的克里特支队，希腊：在挤压楔中以俯冲率折返
DOI：
10.1144/0016-764901-150
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发表时间：
2002
影响因子：
2.7
通讯作者：
T. Reischmann
中科院分区：
文献类型：
--
作者：
U. Ring;T. Reischmann
低角度正断层（determination）只有在滑动速率超过20 km Ma−1的情况下，才能有效地将40->100 km深度的岩石带回地表。在这里，我们建议希腊爱琴海的伊特鲁里亚分遣队的滑动速率为20-30 km Ma−1。中新世古希腊俯冲带上方的挤压楔体是由拉张拆离和俯冲逆冲作用形成的。在折返过程中，楔体中的高压岩石没有明显变形。在边界断层处需要非常低的剪切耦合（因此是弱的），以防止挤压楔中的显著变形。建议的滑动速率为20-30 km Ma−1，与希腊俯冲带的俯冲速率35-45 km Ma−1相似。我们认为，挤压楔只能以类似于俯冲速率的速率滑动，如果有非常低的剪切耦合在边界断层，这也可以解释几乎不变形，但非常迅速折返岩石的悖论。
Low-angle normal faults (detachments) are only efficient agents for bringing rocks from 40–>100 km depth back to the Earth’s surface if they operate with extreme slip rates exceeding 20 km Ma−1. Here we propose a slip rate of ≧20–30 km Ma−1 for the Cretan detachment in the Aegean, Greece. The Cretan detachment and the subjacent subduction thrust bounded an extruding wedge above the Miocene Hellenic subduction zone. During exhumation the high-pressure rocks in the wedge were not significantly deformed. Very low shear coupling at the bounding faults (which are therefore weak) is needed to prevent significant deformation in the extruding wedge. The proposed slip rate of ≧20–30 km Ma−1 is similar to the subduction rate of 35–45 km Ma−1 at the Hellenic subduction zone. We argue that extruding wedges can only slip at rates similar to subduction rates if there is very low shear coupling at the bounding faults, which may also explain the paradox of almost non-deformed but very rapidly exhumed rocks.