Low‐temperature thermochronologic record of Eocene migmatite dome emplacement and late Cenozoic landscape development, Shuswap core complex, British Columbia
Low‐temperature thermochronologic record of Eocene migmatite dome emplacement and late Cenozoic landscape development, Shuswap core complex, British Columbia
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不列颠哥伦比亚省舒斯瓦普核心复合体始新世混合岩圆顶就位和新生代晚期景观发育的低温热年代学记录
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
P. Reiners
中科院分区：
文献类型：
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作者：
E. Toraman;C. Teyssier;D. Whitney;A. Fayon;S. Thomson;P. Reiners
挖出的中下地壳岩石为确定热岩从地壳深部向浅部上升的机制、条件、时间和后果提供了机会。我们使用低温热年代学结果（锆石和磷灰石（U-Th）/He，磷灰石裂变径迹）来记录高品位变质岩的非常浅的就位（<2公里），并确定新生代冷却、折返和随后切割不列颠哥伦比亚省（加拿大）舒斯瓦普变质核复合体的托尔奥丁混合岩穹顶的时间和速率。在穹顶高海拔（>1800米）采集的样本保留了始新世裂变径迹年龄和快速冷却的证据（≥60°C/Myr）。这一始新世冷却事件对应于部分熔融地壳向上流动的快速折返和拆离断层的最终折返。在海拔 1800 米以下采集的样品显示了各种磷灰石裂变径迹年龄（43-15Ma）和径迹长度分布，反映了磷灰石部分退火带的长期停留。这些年龄-海拔关系意味着，在始新世最初的向上流动和构造折返过程中，穹顶岩石到达了近地表（<2公里），并且自那时以来，始新世表面几乎没有发生侵蚀。最低海拔样本（≤~600 m）和样本内磷灰石（U-Th）/He年龄变化的热模拟揭示了~3 Ma大陆冰川作用开始时侵蚀和浮雕的产生增强。我们的工作说明了深部和浅部地壳过程与深切热造山带地形演化之间的动态联系。
Exhumed mid‐to‐lower crustal rocks offer an opportunity to determine the mechanisms, conditions, timing, and consequences of the ascent of hot rocks from deep to shallow crustal levels. We used results of low‐T thermochronology (zircon and apatite (U‐Th)/He, apatite fission track) to document the very shallow emplacement (<2 km) of high‐grade metamorphic rocks and to determine the timing and rates of Cenozoic cooling, exhumation, and subsequent incision of the Thor‐Odin migmatite dome of the Shuswap metamorphic core complex, British Columbia (Canada). Samples collected at high elevation in the dome (>1800 m) have preserved Eocene fission‐track ages and evidence of rapid cooling (≥60°C/Myr). This Eocene cooling event corresponds to rapid exhumation by upward flow of partially molten crust and final exhumation by detachment faulting. Samples collected below 1800 m in elevation display a wide range of apatite fission track ages (43–15 Ma) and track length distributions that reflect prolonged residence in the apatite partial annealing zone. These age‐elevation relations imply that the dome rocks reached the near surface (<2 km) during initial upward flow and tectonic exhumation in the Eocene and that little erosion of the Eocene surface has occurred since that time. Thermal modeling of the lowest elevation samples (≤ ~600 m) and intrasample apatite (U‐Th)/He age variations reveal enhanced erosion and relief production at the onset of continental glaciations at ~3 Ma. Our work illustrates the dynamic links between deep and shallow crustal processes and the evolution of topography in a deeply incised hot orogen.
影响因子：
4.2
作者：
K. Stübner;L. Ratschbacher;D. Rutte;K. Stanek;V. Minaev;M. Wiesinger;R. Gloaguen
通讯作者：
K. Stübner;L. Ratschbacher;D. Rutte;K. Stanek;V. Minaev;M. Wiesinger;R. Gloaguen
印度帕米尔高原巨大的Shakhdara混合岩片麻岩穹顶——亚洲碰撞带：2穹顶形成的时间
影响因子：
4.2
作者：
Stübner;L. Ratschbacher;C. Weise;J. Chow;J. Hofmann;J. Khan;D. Rutte;B. Sperner;J.A. PfänderB.R. Hacker;I. Dunkl;M. Tichomirowa;M.A. Stearns
通讯作者：
M.A. Stearns