Consistency of geologic and geodetic displacements during Andean orogenesis
Consistency of geologic and geodetic displacements during Andean orogenesis
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安第斯造山运动期间地质和大地位移的一致性
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
E. Norabuena
中科院分区：
文献类型：
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作者：
D. Hindle;J. Kley;E. Klosko;S. Stein;T. Dixon;E. Norabuena
目前安第斯山脉中部的位移正在使用高精度 GPS 大地测量学进行测量。到目前为止，由于缺乏足够的地质数据，还无法将变形板块边界区域内的地面运动与地质时间尺度上的地面运动进行比较。在安第斯山脉中部，可以重建过去 25 Ma 造山活动的可比数据集。在这里，我们对 25-10 Ma 和 10 Ma 期间的平均缩短率进行了新的解释，发现虽然位移方向实际上保持恒定和平行，但纳斯卡板块和南美板块之间的收敛速度与减缓同步发生。安第斯山脉的地质缩短率最初为∼5–8 mm yr−1，然后增加到∼10–15 mm yr−1，同时收敛速度从∼150 mm yr−1 减慢到∼70 mm yr−1。从 GPS 和海洋磁力数据推断出的位移和收敛速度表明，这种趋势目前可能仍在持续。因此，越来越多的融合被造山所吸收。这种变化可能反映了由于沉积物供应减少、俯冲岩石圈较年轻或由于隆起作用而导致界面处正应力增加而导致的板块耦合增加。
Present‐day displacements within the Central Andes are being measured using high precision GPS geodesy. Until now, comparison of such ground motions within deforming plate boundary zones to those on a geologic time scale has not been possible due to lack of sufficient geological data. In the Central Andes, a comparable dataset for the past 25 Ma of mountain building can be reconstructed. Here, we use new interpretations of shortening rates averaged over 25–10 Ma and 10 Ma–present and find that whilst displacement directions have remained virtually constant and parallel, an acceleration has occurred synchronously with a slowing of convergence between the Nazca and South American plates. Geologic shortening rates in the Andes are initially ∼5–8 mm yr−1, and increase to ∼10–15 mm yr−1 whilst convergence slows from ∼150 mm yr−1 to ∼70 mm yr−1. Displacement and convergence rates inferred from GPS and marine magnetic data suggest that this trend may be continuing at present. Hence an increasing fraction of convergence is being absorbed by mountain building. This change may reflect increased plate coupling due to decreased sediment supply, younger subducting lithosphere, or increased normal stress at the interface from the effects of uplift.