• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Garnet growth patterns and processes: An analysis of the three-dimensional spatial distribution and compositional zoning patterns in metamorphic garnet from northwest Connecticut and Harpswell Neck, Maine.
【24h】

Garnet growth patterns and processes: An analysis of the three-dimensional spatial distribution and compositional zoning patterns in metamorphic garnet from northwest Connecticut and Harpswell Neck, Maine.

机译：石榴石的生长模式和过程：对西北康涅狄格州和缅因州Harpswell Neck变质石榴石的三维空间分布和成分分区模式的分析。

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 application of serial sectioning and imaging with a flatbed scanner yields the three-dimensional size and spatial distribution of garnet porphyroblasts in metamorphic rocks from northwest Connecticut and Harpswell Neck, Maine. Two garnet-zone and one staurolite-bearing schist from the Everett Formation, northwest Connecticut and one sample each from the garnet-zone, staurolite-zone and andalusite-zone rocks from Harpswell Neck, Maine were examined. Statistical measures of garnet spatial distributions, with the pair correlation function (PCF), indicate that garnet crystals are weakly to strongly clustered at length scales between 2 and 10 mm for the Connecticut samples and 0.5 to 6 mm for the Maine samples. Covariance measures between garnet size and nearest-neighbor distance, using the mark covariance function (MCF), show a weak correlation between crystal size and nearest-neighbor distance for length scales of ≈ 500 mm or less that is inconsistent with the interface-controlled growth simulations. Radius-rate plots calculated from two-dimensional Mn compositional maps indicate that garnet crystals in all samples grew by approximately equal radial increments consistent with an interface-controlled growth model. The statistical and compositional data suggest that diffusional gradients, if present, were small and did not greatly influence nucleation and growth patterns and thus, garnet growth appears to be interface-controlled.; Three-dimensional compositional zoning patterns in garnet-zone garnets from Harpswell Neck, Maine, United States, suggest complex patterns of nucleation and growth. Compositional zoning is often asymmetric, and core compositions do not always coincide with the geometric center of the garnet. In detail, garnet zoning patterns show multiple, isolated high-MnO areas that we interpret as sites of garnet nucleation. Computer-generated, three-dimensional animations of these patchwork MnO zoning patterns reveal that many garnets contain multiple nuclei that grew and coalesced to form a single crystal. New nuclei often appeared next to preexisting porphyroblasts and became incorporated into the growing crystal. Contrary to the widely held idea that garnets grow radially outward from a single nucleus, we propose that many of the garnets examined in this study grew by the coalescence of multiple nuclei.
机译：在平板扫描仪上进行连续切片和成像的应用，可得出康涅狄格西北部和缅因州哈普斯韦尔内克的变质岩中石榴石成矿细胞的三维尺寸和空间分布。对来自康涅狄格州西北部埃弗雷特组的2个石榴石带和1个含辉石的片岩和缅因州Harpswell Neck的石榴石带，星形石带和红柱石带的岩石分别进行了一次取样。石榴石空间分布的统计量度，具有成对相关函数（PCF），表明石榴石晶体在2到10毫米之间的长度尺度上（从康涅狄格州样本到缅因州样本在0.5到6毫米之间）弱到强聚集。使用标记协方差函数（MCF）进行的石榴石尺寸和最近邻距离之间的协方差测量显示，对于 ＆ap; 500 < hsp sp =“ 0.167”> m m 或更少，这与界面控制的增长不一致模拟。由二维Mn组成图计算出的半径速率图表明，所有样品中的石榴石晶体均以近似相等的径向增量生长，与界面控制的生长模型一致。统计数据和成分数据表明，如果存在扩散梯度，则扩散梯度很小，并且不会显着影响成核和生长方式，因此，石榴石的生长似乎受界面控制。来自美国缅因州Harpswell Neck的石榴石带状石榴石中的三维成分分区模式显示出复杂的成核和生长模式。成分分区通常是不对称的，核心成分并不总是与石榴石的几何中心重合。详细地说，石榴石分区模式显示了多个孤立的高MnO区域，我们将其解释为石榴石成核的位置。这些拼凑的MnO分区模式的计算机生成的三维动画显示，许多石榴石包含多个核，这些核生长并聚结在一起形成一个单晶。新核经常出现在原卟啉细胞的旁边，并被掺入到正在生长的晶体中。与普遍认为石榴石从单个原子核向外径向生长的观点相反，我们认为本研究中研究的许多石榴石是通过多个原子核的结合而生长的。

著录项

  • 作者

    Daniel, Christopher G.;

  • 作者单位

    Rensselaer Polytechnic Institute.;

  • 授予单位 Rensselaer Polytechnic Institute.;
  • 学科 Geology.; Mineralogy.
  • 学位 Ph.D.
  • 年度 1998
  • 页码 171 p.
  • 总页数 171
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 地质学;矿物学;
  • 关键词

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