...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Facies >Subtidal stromatolites from the Sinemurian of the Lusitanian Basin (Portugal)
【24h】

Subtidal stromatolites from the Sinemurian of the Lusitanian Basin (Portugal)

机译：Lusitanian盆地Sinemurian的潮下叠层石（葡萄牙）

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

Well-preserved dome-shaped carbonate stromatolites occur in the lowermost part of the Sinemurian of the Lusitanian Basin (Portugal), at S. Pedro de Moel region (W of the basin). Deposition in the region took place on a westward-dipping carbonate ramp. The stromatolitic mounds are not found anywhere else in the Sinemurian of the basin and therefore are regarded as specific bioevents. In contrast to marginal-marine stromatolitic crusts, subtidal carbonate mounds other than sponge-mounds have been seldom reported in the Lower Jurassic, in particular in the Sinemurian, either from Europe or North-Africa. Therefore, the case documented here contributes to enhance the knowledge on stromatolites of this age in the Peri-Tethyan and Proto-Atlantic regions. The depositional setting of the studied succession is interpreted as a mainly low-energy, restricted marine one, punctuated by higher-energy episodes and, locally, subjected to more open marine influence. The existence of a topographic high and detached shoals at a more distal location of the ramp is likely, considering regional seismic evidence, the record in offshore (to the W) wells of peloidal/ooid wacke-packstones with detrital quartz and occurrence of a few ooid grainstones in the studied section. The inferred positive relief would act as a physical constraint that, coupled with the low-gradient of the ramp, defined an embayment-like environment in which the prevailing ecological conditions must have been, for the part of the succession bearing the stromatolites, unfavorable for many benthic organisms, favoring the microbial community. The upper part of the succession suggests stepwise environmental openness to more marine influence alternating with frequent environmental restriction.
机译：保存完好的圆顶形碳酸盐叠层石出现在Lusitanian盆地Sinemurian的最下部（葡萄牙），位于S. Pedro de Moel地区（盆地W）。该区域的沉积发生在向西倾斜的碳酸盐斜坡上。在盆地的Sinemurian的其他任何地方都没有发现叠层石丘，因此被认为是特定的生物事件。与边缘海地层石质地壳相反，下侏罗纪很少有潮汐下的碳酸盐土丘（海绵丘除外）被报道，特别是在西尼穆尔（Sinemurian），来自欧洲或北非。因此，这里记录的病例有助于增强对佩里-特提斯和原始大西洋地区这种年龄的叠层石的了解。研究的演替的沉积环境被解释为主要是低能量的，受限制的海洋生物，被高能事件所打断，并且在局部受到更开放的海洋影响。考虑到区域地震证据，近海（至W）井中碎屑石英的卵状/卵形瓦奇砂砾岩的记录，可能在斜坡的更远端位置存在地形高且分离的浅滩。的研究区中的奥氏体花岗石。推断出的正向起伏将作为一种物理约束，再加上坡道的低坡度，形成了一个类似于浮尘的环境，在该环境中，对于层积岩的部分演替而言，对于继承的层积岩来说，主要的生态条件一定是不利的。许多底栖生物，有利于微生物群落。演替的上部表明，逐步的环境开放对更多的海洋影响与频繁的环境限制交替出现。

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