• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>South African Journal of Geology: Being the Transaction of the Geological Society of South African: Syndie die Verhandelinge van die Geologiese Vereniging van Suid-Afrika >The Aliwal Shoal revisited: New age constraints from nannofossil assemblages
【24h】

The Aliwal Shoal revisited: New age constraints from nannofossil assemblages

机译：重访了Aliwal浅滩：纳米化石组合带来的新时代限制

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

Nannofossil assemblages extracted from rock samples collected at depths of between 33 and 15 metres on the Aliwal Shoal, a submerged aeolianite and beachrock complex on the southeast African continental shelf, indicate a late Middle Pleistocene to Holocene (calcareous nannofossil zone NN21) age for both the aeolianite core and younger abutting beachrocks. This indicates that the older aeolianite core, forming the dune ridge, is no older than ~290 000 years BP. The presence of reworked Cretaceous (Campanian to Maastrichtian), Palaeogene and Pliocene forms in younger beachrocks suggests periodic exposure of those sequences on the outer shelf. The most recent sea level lowstand at approximately –125 m during the Last Glacial Maximum (~18 000 years BP) is considered the most likely event releasing these older forms and their subsequent incorporation into the beachrocks during the ensuing post-Last Glacial transgression.
机译：从东南非洲大陆架上埋没的风成岩和滩石复合体Aliwal浅滩的33至15米深度处采集的岩石样品中提取的Nannofossil组合物表明，这两个时期的中更新世至全新世晚期（钙质nannofossil带NN21）。风成岩芯和较年轻的邻接滩石。这表明形成沙丘脊的较老的风成岩岩心不超过约290 000年BP。在较年轻的滩涂岩石中存在返修的白垩纪（从坎贝尔古到马斯特里赫特），古近纪和上新世形式，表明这些序列在外层架上周期性暴露。在上一次冰川最大爆发期（约BP 18000年）期间，最新的海平面低潮大约发生在–125 m处，被认为是最有可能的事件，这些事件释放了这些较旧的形态，并在随后的上一次冰川期后海侵过程中将其并入滩涂。

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