Abstract This work carries out the analysis, through a geophysical (gravity) method, of an area in the eastern Piedmont of Eastern Precordillera, Central Andes of Argentina. Geological evidence shows several neotectonic reverse fault scarps affecting Quaternary alluvial deposits located to the East of the Sierra de Villicum. Topographic features observed in the understudy region suggest an important Holocene historical seismic activity, one of them the 15th January 1944 San Juan earthquake (Mw 7.0), the worst natural disaster in Argentina. Several N–S springs and carbonate deposits (travertine) are found aligned along the traces of these active faults, disappearing abruptly to the north and south, possibly due to a tectonic control. Travertine deposits are located along fault traces and have been traditionally considered to be contemporaneous with active faults. The existence of travertine bodies deposited by springs, and their low preservation potential, has for the understudy region a neotectonic significance. The eastern Piedmont of the Sierra de Villicum is characterized by the ~N–S La Laja west-vergent east-dipping reverse fault and several subparallel faults (e.g., Cantera and Museo faults) that uplift Neogene sedimentary rocks over Quaternary (Late Pleistocene-Holocene) alluvial deposits. Gravity data derived from the global Earth gravity model WGM 1.0 were used in the regional geophysical analysis. The analysis aims to delimit geological structures, which characterized the interest area. Three detailed gravimetric profiles were measured to analyze local anomalies related to the main structures. The gravimetric and geological analysis confirms the existence of north-south faults parallel to La Laja fault related to travertine deposits. On the other hand, a set of southeast-northwest structures that limit and control the travertine bodies both northward and southward are recognized. Employing the gravity method associated with structural analysis, the spatial continuity of these neotectonic structures was defined in those sectors where field evidence is not so clear or blind structures are present. Our study confirms the existence of probable cross strike structures trending NW. We suggest they would represent preexisting crustal fabrics reactivated during the Andean orogeny in the Precordillera province, segmenting this orogen-parallel fold and belt system. One of the main hypotheses is that these fault systems related to basement-involved strike-slip faults perform as control structures in fluid migration during the travertine bodies' emplacement. Thus, our work points to the relevance of travertine location in the analysis of the seismotectonic configuration of a region.

中文翻译：

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第四纪压缩环境中的地球物理分析控制了阿根廷Precordillera东部山麓石灰华的就位

摘要 这项工作通过地球物理（重力）方法对阿根廷中部安第斯山脉东部 Precordillera 东部皮埃蒙特地区的一个地区进行了分析。地质证据表明，几个新构造逆断层陡坡影响了位于 Sierra de Villicum 以东的第四纪冲积沉积物。在研究区域观察到的地形特征表明发生了一次重要的全新世历史地震活动，其中之一是 1944 年 1 月 15 日圣胡安地震（Mw 7.0），这是阿根廷最严重的自然灾害。发现几个 N-S 泉和碳酸盐沉积物（石灰华）沿着这些活动断层的痕迹排列，向北和向南突然消失，可能是由于构造控制。石灰华沉积物沿断层痕迹分布，传统上被认为与活动断层同时存在。泉水沉积钙华体的存在及其低保存潜力，对研究区具有新构造意义。Sierra de Villicum 东部山麓的特征是 ~N-S La Laja 西向东倾逆断层和几条次平行断层（例如 Cantera 和 Museo 断层）抬升第四纪（晚更新世-全新世）上的新近系沉积岩) 冲积矿床。来自全球地球重力模型 WGM 1.0 的重力数据用于区域地球物理分析。分析的目的是划定地质构造，该构造具有感兴趣区域的特征。测量了三个详细的重力剖面以分析与主要结构相关的局部异常。重力和地质分析证实存在与石灰华沉积物有关的与 La Laja 断层平行的南北断层。另一方面，识别出一组限制和控制钙华体向北和向南的东南-西北构造。使用与结构分析相关的重力方法，这些新构造结构的空间连续性被定义在那些现场证据不太清楚或存在盲结构的扇区中。我们的研究证实了可能存在 NW 趋势的交叉走向结构。我们认为它们代表了在 Precordillera 省的安第斯造山运动期间重新激活的先前存在的地壳结构，分割这个与造山带平行的褶皱和带系统。主要假设之一是这些与基底卷入的走滑断层相关的断层系统在钙华体就位期间作为流体运移的控制结构。因此，我们的工作指出了石灰华位置在分析一个地区的地震构造构造中的相关性。