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首页> 外文期刊>Journal of Volcanology and Geothermal Research >Geology and geochemistry characteristics of the Chiapanecan Volcanic Arc (Central Area), Chiapas Mexico
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Geology and geochemistry characteristics of the Chiapanecan Volcanic Arc (Central Area), Chiapas Mexico

机译：恰帕斯州墨西哥恰帕帕内坎火山弧（中部地区）的地质和地球化学特征

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摘要

The Chiapanecan Volcanic Arc (CVA), located in the central portion of the State of Chiapas, is a 150 km stretch of volcanoes irregularly aligned in the northwest direction between two great volcanic features: the Trans-Mexican Volcanic Belt to the northwest and the Central American Volcanic Arc to the southeast. The CVA is located in a complex zone marking the interaction of the North American, Caribbean and Cocos plates, near the Motagua-Polochic fault system, the boundary between North American and Caribbean plates. The central part of the CVA is composed of an irregular northwest alignment of at least 10 volcanic structures generally lying along NNW-SSE-trending faults splayed from the Motagua-Polochic system. Among the structures there are seven volcanic domes (Huitepec, Amahuitz, La Iglesia, Mispia, La Lanza, Venustiano Carranza and Santoton), one explosion crater (Navenchauc), one collapse structure (Apas), and one dome complex (Tzontehuitz). In the majority of the structures there is a clear resurgence with the formation of several domes in the same structure, with the destruction of previous domes (Navenchauc) or with the formation of new explosion craters or collapse structures (Apas). The volcanic activity in the CVA was mainly effusive accompanied by explosive and phreatomagmatic events and is characterized by volcanic domes accompanied by block-and-ash-flows, ash flows with accretionary lapilli, falls, and pumice flows. The volcanic structures and deposits are calcalkaline in composition with a medium to high content of potassium. CVA volcanic rocks vary from andesite to dacite with SiO_2 between 57 and 66 wt.%, show low concentrations of Ti, P, Nb and Ta, are enriched in Light Rare Earths, depleted in Heavy Rare Earths, and show a small Eu anomaly; all indicative of arc-related volcanism associated with subduction of the Cocos plate under the North American plate, but complicated by the geometry of the plate boundary fault system.
机译：恰恰帕斯坎火山弧（CVA）位于恰帕斯州中部，是一条150公里长的火山，在西北方向不规则地排列着两个主要的火山特征：西北部和中部的跨墨西哥火山带美国东南部的火山弧。 CVA位于一个复杂的区域中，标志着北美，加勒比和科科斯板块之间的相互作用，靠近Motagua-Polochic断层系统，即北美和加勒比板块之间的边界。 CVA的中部由至少10个火山结构的不规则西北向排列组成，这些火山结构通常沿着从Motagua-Polochic系统散布的NNW-SSE趋势断裂分布。在这些结构中，有七个火山圆顶（Huitepec，Amahuitz，La Iglesia，Mispia，La Lanza，Venustiano Carranza和Santoton），一个爆炸坑（Navenchauc），一个坍塌结构（Apas）和一个圆顶复合体（Tzontehuitz）。在大多数建筑物中，随着同一建筑物中几个圆顶的形成，先前圆顶的破坏（Navenchauc）或新的爆炸坑或坍塌结构（Apas）的形成，明显复苏。 CVA中的火山活动主要是爆发性的，伴有爆炸性和岩浆事件，其特征是火山圆顶伴有块状和灰烬流，带有增生性lapilli的灰烬流，跌落和浮石流。火山结构和沉积物的组成为钙碱性，钾含量中等至高。 CVA火山岩从安山岩到菊红岩不等，SiO_2在57至66 wt。％之间，显示出低浓度的Ti，P，Nb和Ta，富含轻稀土元素，贫有重稀土元素，并且表现出较小的Eu异常；所有这些都表明与弧有关的火山作用与北美板块下的Cocos板块俯冲有关，但由于板块边界断层系统的几何形状而变得复杂。

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