...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of geodynamics >Cretaceous subduction-related volcanism in the northern Sanandaj-Sirjan Zone, Iran
【24h】

Cretaceous subduction-related volcanism in the northern Sanandaj-Sirjan Zone, Iran

机译：伊朗北部Sanandaj-Sirjan区与白垩纪俯冲有关的火山活动

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

Cretaceous volcanic rocks (SCV) are widely developed in the northern part of the Sanandaj-Sirjan Zone, northwest Iran. Based on the mineralogy, texture and geochemical composition these rocks are divided in two main groups, the first and main one situated in the central part of the study area and the second one in the northeast. The former is dominantly basalts, andesitic basalts, and andesites and the latter comprises andesite, trachy-andesite to acidic variants, with porphyritic to microlithic porphyry and vitrophyric textures. Beside the differences between these two groups, the chemical compositions all of these rocks show a calc-alkaline affinity and enrichment in LIL elements (Rb, Ba, Th, U, and Pb) and depletion in Nb, Ti, and Zr, as evident in spider diagrams normalized to primitive mantle. The rocks are particularly enriched in Rb and depleted in Nb and Ti, as well as displaying high Rb/Sr and Rb/Ba ratios and low ratios of incompatible elements such as Nb/U (<10; range, 0.6-9), Th/U (<2), and Ba/Rb (<20). The significant U enrichment relative to neighbouring Nb and Th in the mantle-normalized variation diagram is mainly a result of source enrichment by slab-derived fluids. Significantly lower Nb/U ratios are observed in arc volcanics. These low values are generally ascribed to the strong capacity of LILE and the inability to transfer significant amounts of HFSE via slab-derived hydrous fluid. The results of geochemical modelling suggest a mantle lithospheric source that was metasomatized by fluids derived from a Neo-Tethyan subducted slab during the Middle to Late Cretaceous in the northern part Sanandaj-Sirjan Zone.
机译：白垩纪火山岩（SCV）在伊朗西北部的Sanandaj-Sirjan区北部广泛发育。根据矿物学，质地和地球化学组成，这些岩石分为两个主要类别，第一个和主要一个位于研究区域的中部，第二个位于东北。前者主要是玄武岩，安山岩玄武岩和安山岩，而后者则包括安山岩，石-安山岩到酸性变体，斑状到微石斑岩和玻璃质。除了这两组之间的差异外，所有这些岩石的化学成分都显示出钙碱性亲和力和LIL元素（Rb，Ba，Th，U和Pb）的富集，以及Nb，Ti和Zr的耗竭。在标准化为原始地幔的蜘蛛图中。岩石特别富含Rb，Nb和Ti贫乏，并且具有高的Rb / Sr和Rb / Ba比值和低的不相容元素比值，例如Nb / U（<10；范围0.6-9），Th / U（<2）和Ba / Rb（<20）。在地幔归一化变化图中相对于相邻Nb和Th的显着U富集主要是板坯衍生流体对源进行富集的结果。在弧形火山中观察到的Nb / U比值明显较低。这些较低的值通常归因于LILE的强大功能以及无法通过源自平板的含水流体转移大量HFSE。地球化学模拟的结果表明，在北部Sanandaj-Sirjan地区中白垩纪晚期至新白垩纪俯冲板块衍生的流体对地幔岩石圈源进行了交代。

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