...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Contributions to Mineralogy and Petrology >Crystallisation and zircon saturation of calc-alkaline tonalite from the Adamello Batholith at upper crustal conditions: an experimental study
【24h】

Crystallisation and zircon saturation of calc-alkaline tonalite from the Adamello Batholith at upper crustal conditions: an experimental study

机译：钙碱性四氧化铝的结晶和锆石饱和在上层地壳条件下的亚氨基醇：实验研究

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

The understanding of the geochemical and petrophysical evolution of magmas forming intermediate calc-alkaline batholiths at shallow crustal levels critically depends on knowledge of the phase equilibria relations along the liquid line of descent. Here, we present experimental results for a tonalitic system at a pressure of 200 MPa and under water-saturated conditions. Melting experiments were performed at temperatures between 700 and 1000 degrees C in externally heated HCM pressure vessels, with oxygen fugacity controlled close to the Ni-NiO buffer equilibrium (NNO) employing an argon-methane mixture as pressure medium and Co-Pd redox sensors to verify fO(2) conditions. Natural rock powder of a medium-K tonalite from the Adamello Batholith in Northern Italy served as experimental starting material. Based on compositional data of stable phases in the run products and images of entire run charges, mass balance calculations as well as image processing were performed to investigate the evolution of the crystal/melt ratio with respect to temperature. Furthermore, compositional trends of minerals as well as the liquid line of descent of residual melts were obtained. Orthopyroxene, clinopyroxene and plagioclase were identified as near-liquidus phases (below 990 degrees C). At 900 degrees C, amphibole joins the solid-phase assemblage at the expense of clinopyroxene, indicating the existence of a peritectic relationship. After an initial near-linear decrease with temperature, residual melt fractions exhibit a plateau of 45-55 vol. % between 750 and 850 degrees C, followed by a rapid decrease coinciding with quartz saturation at 725 degrees C. Compositions of residual liquids evolve along a typical calc-alkaline differentiation trend with decreasing temperature (increasing SiO2 and decreasing TiO2, Al2O3, CaO, MgO and FeO contents) and become peraluminous below 900 degrees C. Intermediate to acidic rocks from the Adamello follow the experimental liquid line of descent indicating that the observed compositional spread of the natural intermediate composition rock record can be explained by low-pressure magma differentiation and liquid extraction. Experimentally determined zircon saturation levels are at low temperatures distinctly lower compared to existing and often used Zr-saturation models, but fully consistent with observed and modelled Zr-evolution trends from the natural rock record of the Southern Adamello Batholith inferring that zircon saturation in these intermediate to felsic plutonic rocks occurred at 800-830 degrees C corresponding to a melt fraction of about 50 vol. %.
机译：在浅地壳水平下形成中间钙碱性浴池的岩浆和岩石物理演化的理解重点取决于沿液体液体线的相平关系知识。在这里，我们在200MPa的压力下呈现色调系统的实验结果，并在水饱和条件下。在外部加热的HCM压力容器中在700-1000℃的温度下进行熔化实验，氧不受约束接近使用氩甲烷混合物作为压力培养基和Co-Pd氧化还原传感器的Ni-NiO缓冲液平衡（NNO）。验证fo（2）条件。来自意大利北部的Adamello Batholith的中等K Tonalite的天然岩石粉末作为实验起始材料。基于运行产品中稳定阶段的组成数据和整个运行电荷的图像，进行质量平衡计算以及图像处理，以研究晶体/熔体比率相对于温度的进化。此外，获得了矿物质的组成趋势以及残留熔体的下降液体。将冠状肾上腺素，临床和Plagioclase鉴定为接近液相（低于990℃）。在900摄氏度下，锥形锥加入固相组合，以临床的牺牲，表明存在包层关系。在用温度初始近线性降低之后，残留的熔体馏分表现出45-55体积的平台。 750至850℃之间的％，然后在725℃下与石英饱和的快速减少。残留液体的组成沿典型的钙碱性分化趋势随着较低的温度（增加SiO 2和减少TiO 2，Al2O3，CaO，MgO）。和Feo含量）并且变得低于900℃的灭菌。从Adamello中间体到酸性岩石遵循实验液体的液体线，表明可以通过低压岩浆分化和液体来解释观察到的天然中间体成分岩石记录的组成扩散萃取。实验确定的锆石饱和水平在低温下与现有和经常使用的Zr饱和模型明显降低，但与来自南部南部浴池的天然摇滚记录推断这些中间体中的Zircon饱和度的观察和建模的Zr演化趋势完全一致对于柔滑的岩石岩石发生在800-830摄氏度，对应于约50体积的熔体分数。 ％。

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