Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah, 85721, USA.
Department of Geosciences, University of Arizona, Tucson, Arizona, 85721, USA.
Sci Rep. 2017 Aug 22;7(1):9047. doi: 10.1038/s41598-017-09015-5.
The role of magmatic processes as a significant mechanism for the generation of voluminous silicic crust and the development of Cordilleran plateaus remains a lingering question in part because of the inherent difficulty in quantifying plutonic volumes. Despite this difficulty, a growing body of independently measured plutonic-to-volcanic ratios suggests the volume of plutonic material in the crust related to Cordilleran magmatic systems is much larger than is previously expected. To better examine the role of crustal magmatic processes and its relationship to erupted material in Cordilleran systems, we present a continuous high-resolution crustal seismic velocity model for an 800 km section of the active South American Cordillera (Puna Plateau). Although the plutonic-to-volcanic ratios we estimate vary along the length of the Puna Plateau, all ratios are larger than those previously reported (30:1 compared to 5:1) implying that a significant volume of intermediate to silicic plutonic material is generated in the crust of the central South American Cordillera. Furthermore, as Cordilleran-type margins have been common since the onset of modern plate tectonics, our findings suggest that similar processes may have played a significant role in generating and/or modifying large volumes of continental crust, as observed in the continents today.
岩浆作用作为一种重要机制，在大规模硅质壳的形成和科迪勒拉高原的发育中扮演着重要角色，但这一作用仍存在争议，部分原因是难以定量估算深成岩体积。尽管存在这一困难，但越来越多的独立测量结果表明，与科迪勒拉岩浆系统相关的地壳深成岩体积比之前预期的要大得多。为了更好地研究地壳岩浆作用的作用及其与科迪勒拉系统喷发物质的关系，我们为南美洲活动科迪勒拉山脉（普纳高原）的一个约 800 公里长的地段提供了一个连续的高分辨率地壳地震速度模型。尽管我们估算的深成岩与火山岩比值沿普纳高原的长度变化，但所有比值都大于之前报告的值（约 30:1 与 5:1 相比），这意味着在南美洲中部科迪勒拉山脉的地壳中产生了大量的中酸性深成岩物质。此外，由于科迪勒拉型边缘自现代板块构造开始以来一直很常见，我们的发现表明，类似的过程可能在形成和/或改造大量大陆地壳方面发挥了重要作用，就像今天在大陆上观察到的那样。
