摘要
鄂尔多斯地区南缘奥陶纪可划分为12个层序(sequences).本区奥陶纪地壳演化正处于重要关键时期,早奥陶世(冶里-亮甲山期、马家沟期、峰峰期)为被动大陆边缘,划分为7个层序.海平面突然上升,尔后逐渐下降.中、晚奥陶世(赵老峪期、上店期)演化为主动大陆边缘,可划分为5个层序.海平面就鄂尔多斯地区整体而言发生大规模海退,露出海面.但就鄂尔多斯地区南缘则海水突然加深,随后海平面渐渐下降.晚奥陶世卡拉道克世末鄂尔多斯地区海水全部退出.
Four evolutional stages including low-energy and high-energy ramp, rimmed shelf with restricted inner-shelf basin, rimmed shelf with envoloped inner-shelf basin and carbonate faulted margin can be distinguished for Early Paleozoic carbonate platform in the southern margin of Ordos basin. Each stage developed different high-frequency cycles, suggesting that the depositional setting controlled the diversity of carbonate high-frequency cycles. The 4:1 bunding of fifth-order cycles within fourth-order cycles and the 5:1 bunding of sixth-order cycles within fifth-order cycles as well as calculation of period for cycles within the first stage show that the driving force is related to Milankovitch orbital periodicity.
出处
《地球科学(中国地质大学学报)》
EI
CAS
CSCD
北大核心
1997年第5期491-503,共13页
Earth Science-Journal of China University of Geosciences
基金
国家基础性研究重大项目"中国古大陆及其边缘层序地层及海平面变化研究(SSLC)"资助
关键词
奥陶纪
海平面变化
沉积体系
层序地层
盆地
evolutional stage of carbonate platform, high-frequency cycle, Milankovitch orbital, periodicity, southern margin of Ordos basin, Early Paleozoic.