Denali fault slip rates and Holocene-late Pleistocene kinematics of central Alaska
Denali fault slip rates and Holocene-late Pleistocene kinematics of central Alaska
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阿拉斯加中部的迪纳利断层滑动速率和全新世晚期更新世运动学
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
T. Dawson
中科院分区：
文献类型：
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作者：
A. Matmon;D. P. Schwartz;P. Haeussler;R. Finkel;J. Lienkaemper;H. Stenner;T. Dawson
德纳利断裂是主要的陆内走滑断裂，与雅库塔特板块会聚有关，为阿拉斯加内部的变形提供了便利。通过对错位地貌地貌的定年，首次获得了德纳利断裂系统晚更新世-全新世的定量滑动速率。对德纳利和托顺达断裂错开25-170m的7个地点的巨石(n=27)和沉积物(n=13)中的宇宙成因10Be浓度进行了分析，给出了平均年龄范围为2.4±0.3 ka到17.0±1.8 ka。这些偏移量和年龄产生了晚更新世-全新世的平均滑动速率，沿德纳利断裂的西、中、东方向分别为9.4±1.6、12.1±1.7和8.4±2.2 mm/年−1，沿托顺达断裂为6.0±1.2 mm/年的−1。我们的结果表明，更新世-全新世的平均滑动速率向西减小。这种向西的减少可能是由于从德纳利断层系统向北和向西的逆冲断层滑动的分割造成的。
The Denali fault is the principal intracontinental strike-slip fault accommodating deformation of interior Alaska associated with the Yakutat plate convergence. We obtained the first quantitative late Pleistocene–Holocene slip rates on the Denali fault system from dating offset geomorphic features. Analysis of cosmogenic 10Be concentrations in boulders ( n = 27) and sediment ( n = 13) collected at seven sites, offset 25–170 m by the Denali and Totschunda faults, gives average ages that range from 2.4 ± 0.3 ka to 17.0 ± 1.8 ka. These offsets and ages yield late Pleistocene– Holocene average slip rates of 9.4 ± 1.6, 12.1 ± 1.7, and 8.4 ± 2.2 mm/yr−1 along the western, central, and eastern Denali fault, respectively, and 6.0 ± 1.2 mm/yr−1 along the Totschunda fault. Our results suggest a westward decrease in the mean Pleistocene– Holocene slip rate. This westward decrease likely results from partitioning of slip from the Denali fault system to thrust faults to the north and west.