Structural control of monogenetic volcanism in the Garrotxa volcanic field (Northeastern Spain) from gravity and self-potential measurements
Structural control of monogenetic volcanism in the Garrotxa volcanic field (Northeastern Spain) from gravity and self-potential measurements
复制标题
通过重力和自势测量对 Garrotxa 火山场（西班牙东北部）单生火山活动进行结构控制
DOI：
10.1007/s00445-013-0788-0
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发表时间：
2014
影响因子：
3.5
通讯作者：
A. Sánchez
中科院分区：
文献类型：
--
作者：
S. Barde‐Cabusson;J. Gottsmann;J. Martí;X. Bolós;A. G. Camacho;Adelina Geyer;L. Planagumà;E. Ronchin;A. Sánchez
我们报告新的地球物理观测的地下结构的分布与单成因火山在Garrotxa火山领域（北方西班牙）。作为加泰罗尼亚火山区的一部分，这个第四纪火山区与欧洲裂谷系统有关。它包含了加泰罗尼亚火山区最新和保存最完好的火山建筑，在Garrotxa自然公园中发现了38座单成因火山。我们进行了新的重力和自然电位调查，以提高我们对当地地质和单成因火山的空间分布之间的关系的理解。这项研究的主要发现是，火山区的中心部分主要是一个大约-0.5 mGal的广泛的负布格异常，其中发现了一系列重力极小值，振幅高达-2.3 mGal。布格数据的反演模型表明，表层低密度物质占主导地位的火山领域，最有可能与喷出和爆炸性的表面沉积物。相比之下，一个弧形集群的重力极小西北的Croscat火山，这一带最年轻的火山，模拟垂直延伸的低密度机构，我们解释为一个复杂的合奏故障损害区和年轻的火山渣锥的根。一个地下水渗透带确定的自电位异常与陡峭的水平布格重力梯度，并解释为断层带和/或岩浆裂缝，其中美联储最近的火山活动在Garrotxa。重力和自然电位数据有很好的相关性，并表明控制的火山渣锥的位置由NNE-SSW和NNW-SSE走向的构造特征，相交的主要构造边界的研究区的北部和南部。我们对这些数据的解释是，断层促进了岩浆上升到地表。我们的研究结果对于了解Garrotxa火山区地下结构与未来潜在火山活动之间的关系具有重要意义。
We report new geophysical observations on the distribution of subsurface structures associated with monogenetic volcanism in the Garrotxa volcanic field (Northern Spain). As part of the Catalan Volcanic Zone, this Quaternary volcanic field is associated with the European rifts system. It contains the most recent and best preserved volcanic edifices of the Catalan Volcanic Zone with 38 monogenetic volcanoes identified in the Garrotxa Natural Park. We conducted new gravimetric and self-potential surveys to enhance our understanding of the relationship between the local geology and the spatial distribution of the monogenetic volcanoes. The main finding of this study is that the central part of the volcanic field is dominated by a broad negative Bouguer anomaly of around −0.5 mGal, within which a series of gravity minima are found with amplitudes of up to −2.3 mGal. Inverse modelling of the Bouguer data suggests that surficial low-density material dominates the volcanic field, most likely associated with effusive and explosive surface deposits. In contrast, an arcuate cluster of gravity minima to the NW of the Croscat volcano, the youngest volcano of this zone, is modelled by vertically extended low-density bodies, which we interpret as a complex ensemble of fault damage zones and the roots of young scoria cones. A ground-water infiltration zone identified by a self-potential anomaly is associated with a steep horizontal Bouguer gravity gradient and interpreted as a fault zone and/or magmatic fissure, which fed the most recent volcanic activity in the Garrotxa. Gravimetric and self-potential data are well correlated and indicate a control on the locations of scoria cones by NNE–SSW and NNW–SSE striking tectonic features, which intersect the main structural boundaries of the study area to the north and south. Our interpretation of the data is that faults facilitated magma ascent to the surface. Our findings have major implications for understanding the relationship between subsurface structures and potential future volcanic activity in the Garrotxa volcanic field.