A plutonic brother from another magma mother: Disproving the Eocene Foraker‐McGonagall pluton piercing point and implications for long‐term slip on the Denali Fault
A plutonic brother from another magma mother: Disproving the Eocene Foraker‐McGonagall pluton piercing point and implications for long‐term slip on the Denali Fault
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DOI：
10.1111/ter.12437
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发表时间：
2019-11
期刊：
影响因子：
2.4
通讯作者：
S. Regan;J. Benowitz;M. Holland
中科院分区：
文献类型：
--
作者：
S. Regan;J. Benowitz;M. Holland
德纳里断层是一个活跃的走滑断层系统，负责北美最高的地形，但有矛盾的限制断层的新生代滑动历史。自57 Ma以来，Denali东部断层的长期滑动速率限制约为400 km。在明显的冲突中，根据Foraker和McGonagall岩体的重建，自38 Ma以来，Denali断层西部的长期滑动速率为38 km。通过大块岩石地球化学和成对的U-Pb和Hf锆石分析，对岩体的成因关系进行了测试，结果表明它们的起源不同。麦格岩体尽管SiO2含量较低，但εHf值较低，这与两者之间的化学和同位素变化不一致，这是污染的结果。德纳里断层是一个高度应变的分区系统，但新生代的滑动量从东到西的分散可能比以前的约360公里的限制显着减少。
The Denali Fault is an active strike‐slip fault system responsible for the highest topography in North America, yet there are conflicting constraints on the fault's Cenozoic slip history. The long‐term slip rate constraint of the eastern Denali Fault is ~400 km since 57 Ma. In apparent conflict, the long‐term slip rate of the western Denali Fault is 38 km since 38 Ma based on the reconstruction of the Foraker and McGonagall plutons. Tests of the genetic relationship of the plutons with bulk rock geochemical and paired U‐Pb and Hf zircon analysis suggest a disparate origin. The McGonagall pluton, despite having a lower SiO2, has lower εHf values inconsistent with chemical and isotopic variations between the two being the result of contamination. The Denali Fault is a highly strain partitioned system, but the amount of Cenozoic slip dispersed east to west is likely significantly less than the previous ~360 km constraint.