Moho interface beneath Yakutat terrane, southern Alaska
Moho interface beneath Yakutat terrane, southern Alaska
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阿拉斯加南部雅库塔特地体下方的莫霍面界面
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
T. Pavlis
中科院分区：
文献类型：
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作者：
G. Christeson;H. Avendonk;S. Gulick;R. Reece;G. Pavlis;T. Pavlis
我们使用海底和陆地地震仪记录的气枪射击来约束阿拉斯加南部雅库塔特地区的3-D速度结构和莫霍界面深度。我们使用来自64个接收器的约61，000个初至拾取的层析反演来创建3D速度模型。海岸线以北的平均速度-深度函数在地表的速度约为4-5 km/s，在地表以下约12-13 km处的速度增加到>6 km/s。靠近海岸的平均速度（3.8公里/秒）比最高地形下的平均速度（4.7公里/秒）要慢。我们对来自50个接收器的~ 19，000 PmP反射拾取进行界面反演，以约束二维莫霍界面模型。在我们研究区域的海洋部分，雅库塔特河的平均莫霍面深度约为30 km，但在Chugach‐St的高地形下，深度迅速增加到陆上的40-45 km。伊莱亚斯山脉莫霍面深度与造山带下的艾里等值线一致。我们的数据集支持一个连续的莫霍面在基地的Yakutat Yakutat，没有证据表明太平洋洋壳下冲的Yakutat Yakutat。我们提出了几个地质模型下的地壳增厚楚加奇-圣。与地震观测和地表地质相一致的Elias造山带模型，并将这些模型与该地区的地质填图进行了比较。我们认为，地壳增厚和地形在楚加奇-圣。伊莱亚斯山脉是通过双重系统获得的，该系统产生垂直生长的沉积和变质沉积物的反形式堆叠。
We use air gun shots recorded by ocean‐bottom and land seismometers to constrain a 3‐D velocity structure and a Moho interface depth for the Yakutat terrane in southern Alaska. We use a tomographic inversion of ~61,000 first‐arrival picks from 64 receivers to create a 3‐D velocity model. The average velocity‐depth function north of the coastline has velocities at the surface of ~4–5 km/s, increasing to velocities of >6 km/s at ~12–13 km below the surface. Average velocities at the surface are slower near the coast (3.8 km/s) than under the highest topography (4.7 km/s). We carry out an interface inversion of ~19,000 PmP reflection picks from 50 receivers to constrain a 2‐D Moho interface model. The average Moho depth of the Yakutat terrane in the marine portion of our study area is ~30 km, but depth rapidly increases onshore to 40–45 km beneath the high topography of the Chugach‐St. Elias Mountains. Moho depths are consistent with Airy isostasy beneath the orogen. Our data set supports a continuous Moho at the base of the Yakutat terrane, with no evidence for Pacific oceanic crust underthrusting the Yakutat terrane. We present several geologic models for crustal thickening beneath the Chugach‐St. Elias orogen that are consistent with the seismic observations and surface geology and compare these models with geologic mapping in the region. We argue that crustal thickening and topography at the Chugach‐St. Elias Mountains is obtained via a duplex system that produces a vertically growing antiformal stack of sedimentary and metasedimentary material.
影响因子：
2.8
作者：
C. Plattner;R. Malservisi;T. Dixon;P. LaFemina;G. Sella;J. Fletcher;F. Suárez‐Vidal
通讯作者：
C. Plattner;R. Malservisi;T. Dixon;P. LaFemina;G. Sella;J. Fletcher;F. Suárez‐Vidal