...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Volcanology and Geothermal Research >Buried Rhyolites Within The Active, High-temperature Salton Sea Geothermal System
【24h】

Buried Rhyolites Within The Active, High-temperature Salton Sea Geothermal System

机译：活跃的高温索尔顿海地热系统中的埋藏流纹岩

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Previously unrecognized pulses of rhyolite volcanism occurred in the Salton Trough between 420±8 ka and 479 ±38 ka (2σ), based on high-spatial resolution U-Pb zircon geochronology. Presently, these rhyolite lavas, tuffs and shallow subvolcanic sills are buried to depths between～1.6 and 2.7 km at ambient temperatures between 200 and 300 ℃, and are overprinted by propylitic to potassic hydrothermal alteration mineral assemblages consisting of finely intergrown quartz, K-feldspar, chlorite, epidote, and minor pyrite. Alteration resistant geochemical indicators (whole-rock Nd-isotopes, zircon oxygen-isotopes) reveal that these rhyolites are derived from remelting of MORB-type crust that was chilled and hydrothermally altered by deep-circulating hydrothermal waters. U-Pb zircon dating confirms the presence of Bishop Tuff in well State 2-14 at～1.7 km depth, approximately 5 km NE of the geothermal wells that penetrated the buried rhyolites. These results indicate accelerated subsidence towards the center of the Salton Trough, increasing from 2.2 mm/a to 3.8 mm/a. Based on these results, the present-day Salton Sea geothermal field is identified as a focus zone of episodic rhyolitic volcanism, intense heat flow and metamorphism that predates present-day geothermal activity and Holocene volcanism by at least ～400 ka.
机译：根据高空间分辨率的U-Pb锆石年代学，流纹岩火山活动以前无法识别的脉冲发生在Salton槽中，介于420±8 ka和479±38 ka（2σ）之间。目前，这些流纹岩熔岩，凝灰岩和浅火山下基石在200至300℃的环境温度下埋藏在约1.6至2.7 km的深度，并被丙炔化成钾，由钾肥组成，由精细共生的石英，钾长石组成，绿泥石，附子和少量黄铁矿。耐蚀变的地球化学指示剂（整个岩石的Nd同位素，锆石氧同位素）表明，这些流纹岩是由MORB型地壳的重熔衍生而来的，该铸壳是通过深循环的热水来冷却和热液化的。 U-Pb锆石测年证实了Bishop Tuff在状态2-14的井中存在，深度约为1.7 km，大约是穿透埋藏流纹岩的地热井的东北5 km。这些结果表明，向Salton槽中心的沉降速度加快，从2.2毫米/年增加到3.8毫米/年。根据这些结果，当前的萨尔顿海地热场被确定为是偶发的流纹岩性火山岩，强烈的热流和变质作用的一个重点区域，比现今的地热活动和全新世火山早了至少400 ka。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号