GOCE satellite derived gravity and gravity gradient corrected for topographic effect in the South Central Andes region
GOCE satellite derived gravity and gravity gradient corrected for topographic effect in the South Central Andes region
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DOI：
10.1111/j.1365-246x.2012.05556.x
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发表时间：
2012-08
影响因子：
2.8
通讯作者：
O. Álvarez;M. Gimenez;C. Braitenberg;A. Folguera
中科院分区：
文献类型：
--
作者：
O. Álvarez;M. Gimenez;C. Braitenberg;A. Folguera
全球重力场模型是由卫星测量与地面观测相结合而得到的，提供了一个具有高空间分辨率和精度的地球重力场模型。地球重力模型EGM08是地球重力势的2159次球谐展开，并应用该模型计算了应用于安第斯山脉中南部地区的重力异常和垂直重力梯度两个地球重力函数。利用卫星GOCE的观测，开发了最高分辨率的纯卫星场，可达250度和250阶。地形效应是卫星重力梯度数据向下延拓和验证的基本量，它是由数字高程模型转换成一组曲面来计算的。该数据用于计算异常电位和垂直重力梯度。中南部安第斯地区的地质构造非常复杂，但尚未得到很好的解析。重力异常和垂直梯度的处理和解释可以与地质图和已知构造进行比较。以此为基础，可以清楚地描绘出太平洋地壳与安第斯褶皱和冲断带的接触、大洋性纳斯卡板块上的海山链、法马汀和潘潘亚山脉等特征。此外，里约热内卢de la Plata克拉通和Pampia地形之间的接触非常有趣，因为它代表了一个直到现在还没有明确定义的边界。另一个伟大的线条，瓦利富里-德萨瓜德罗巨型线条，表达了圭亚尼亚和潘皮亚大地之间的接触，也可以清楚地描绘出来。作者试图证明新的重力场可以用来识别地质特征，从而成为地球物理勘探中有用的创新工具。
SUMMARY Global gravity field models, derived from satellite measurements integrated with terrestrial observations, provide a model of the Earth's gravity field with high spatial resolution and accuracy. The Earth Gravity Model EGM08, a spherical harmonic expansion of the geopotential up to degree and order 2159, has been used to calculate two functionals of the geopotential: the gravity anomaly and the vertical gravity gradient applied to the South Central Andes area. The satellite-only field of the highest resolution has been developed with the observations of satellite GOCE, up to degree and order 250. The topographic effect, a fundamental quantity for the downward continuation and validation of satellite gravity gradiometry data, was calculated from a digital elevation model which was converted into a set of tesseroids. This data is used to calculate the anomalous potential and vertical gravity gradient. In the Southern Central Andes region the geological structures are very complex, but not well resolved. The processing and interpreting of the gravity anomaly and vertical gradients allow the comparison with geological maps and known tectonic structures. Using this as a basis, a few features can be clearly depicted as the contact between Pacific oceanic crust and the Andean fold and thrust belt, the seamount chains over the Oceanic Nazca Plate, and the Famatinian and Pampean Ranges. Moreover the contact between the Rio de la Plata craton and the Pampia Terrain is of great interest, since it represents a boundary that has not been clearly defined until now. Another great lineament, the Valle Fertil-Desaguadero mega-lineament, an expression of the contact between Cuyania and Pampia terranes, can also be clearly depicted. The authors attempt to demonstrate that the new gravity fields can be used for identifying geological features, and therefore serve as useful innovative tools in geophysical exploration.