...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Diagenetic formation of bedded chert: Implications from a rock magnetic study of siliceous precursor sediments
【24h】

Diagenetic formation of bedded chert: Implications from a rock magnetic study of siliceous precursor sediments

机译：卧式燧石的成岩形成：硅质前体沉积物的岩石磁性研究的影响

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

Bedded chert is a distinctive rock type characterized by a rhythmic alternation of quartz-rich chert beds and clay-rich interbeds. The origin of the lithologic variations is not well understood. A rock magnetic study of a sequence of alternating bands of radiolarian-rich and clay-rich bands recovered by ODP leg 129, which is considered to be the best-known analog for the bedded chert precursor sediments, shows that the relative abundances and characteristics of magnetic phases are similar in both sediment types, with only a minor (1.5 times on average) increase in bulk concentration in clay-rich bands. Comparison with magnetic properties of the diagenetically mature chert-shale couplets suggests that siliceous precursor sediments undergo strong differential diagenetic modification. A simple silica transfer model, with dissolution of silica in proto-shale donor beds and deposition in proto-chert receiver beds, indicate that the known features of the bedded chert sequences, such as the difference in thickness, cosmic dust content between chert and shale, can be reproduced in case of donor beds having initially lower clay (higher biogenic silica) content compared to receiver beds. While contrary to the current depositional model explaining chert beds formation by episodic radiolarian bloom on a background of slow accumulation of clays, an association of proto-shale beds with high productivity episodes is supported by an independent paleoproductivity proxy - their higher Al/Ti values, and is in full agreement with the known silica diagenesis trends, particularly, with the retarding influence of detrital minerals on silica transformations. The impetus for diagenetic silica segregation is provided by initial variability in clay content within a siliceous sedimentary succession. Silica dissolution starts in clay-poor intervals. When diffusing silica encounters clay-rich beds, adsorption to clay lowers dissolved silica content below the saturation level of the higher solubility phases and leads to deposition of low solubility quartz. Early deposition of quartz cement prevents significant compaction of chert layers, while the loss of silica in donor beds leads to their compaction and concomitant increase in non-reactive clay and cosmic dust particles. Severe distortion of primary environmental signals during differential diagenesis questions the use of bedded chert sequences for cyclostratigraphic studies. (C) 2019 The Author(s). Published by Elsevier B.V.
机译：硅质岩是一个独特的岩石类型特点是富含石英燧石床和丰富的粘土夹层有节奏的交替。岩性变化的起源还不是很清楚。富粘土放射丰富且带的交替的带的一个序列的岩石磁性研究回收由ODP腿129，其被认为是所述的有道床燧石前体沉积的最知名的模拟，示出了相对丰度和特性磁性相在两种沉积物类型相似，只有一小批量浓度在富粘土带增加（平均1.5倍）。与成岩成熟燧石页岩对联磁特性比较表明，前体硅质沉积物经受强差成岩修饰。一个简单的硅传输模式，与在原页岩施主床二氧化硅的溶解和沉积在原燧石接收机床，指示该层状燧石序列的公知的特征，如燧石和页岩之间的厚度差，宇宙尘埃内容，可以在具有较低初始粘土（较高生物来源二氧化硅）供体的床相比，接收器的床内容的情况下被再现。虽然违背了当前沉积模式解释硅质岩床的形成由偶发放射绽放粘土的缓慢积累的背景下，以高生产率发作原泥岩层的关联是通过一个独立的古生产力的代理支持 - 其较高的铝/钛值，并与已知的硅石成岩作用的趋势，尤其是完全一致，与碎屑矿物的硅胶转换的延迟影响。对于成岩二氧化硅偏析的推动力是由初始变性硅质沉积序列内提供在粘土含量。硅开始溶解在粘土差区间。当漫射二氧化硅遇到富粘土床，吸附到粘土降低溶解下面的更高的溶解度相和引线的饱和电平到低溶解度石英沉积二氧化硅含量。石英水泥防止燧石层显著压实早期沉积，而二氧化硅的在供体床引线在非反应性粘土和宇宙尘埃颗粒的损失他们的压实和伴随增加。期间差动成岩问题主要环境信号的严重失真的使用为cyclostratigraphic研究层状燧石序列。 （c）2019年作者。由elsevier b.v出版。

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