| 藏北安多东巧地区晚侏罗世生物礁古生态学研究 |
| |
| 引用本文： | 肖传桃,夷晓伟,李梦,李超.藏北安多东巧地区晚侏罗世生物礁古生态学研究[J].沉积学报,2011,29(4):752-760. |
| |
| 作者姓名： | 肖传桃 夷晓伟 李梦 李超 |
| |
| 作者单位： | 长江大学油气资源与勘探技术教育部重点实验室 湖北荆州 434023 |
| |
| 基金项目： | 国家自然科学基金项目(批准号:40972019);湖北省教育厅计划类科技项目;国家大学生创新性实验计划资助成果 |
| |
| 摘 要： | 安多东巧地区上侏罗统沙木罗组主要为一套潮坪相碎屑及台地相碳酸盐沉积,其中的特征沉积是发育有生物礁。造礁生物主要为层孔虫,其次为珊瑚,其中,层孔虫又可以分为筒状、块状和枝状3种宏观形态。在对造礁生物的个体生态学分析基础上,根据其组合特征,将生物礁划分为3个造礁群落,分别是Milleporidium—Cladocorops...
|
| 关 键 词： | 生物礁 古生态学 海平面变化 晚侏罗世 藏北地区 |
| 收稿时间： | 1900-01-01 |
Study on Palaeoecology of Late Jurassic Reefs in Dongqiao Area in Anduo County of Northern Tibet |
| |
| XIAO Chuan-tao,YI Xiao-wei,LI Meng,LI Chao.Study on Palaeoecology of Late Jurassic Reefs in Dongqiao Area in Anduo County of Northern Tibet[J].Acta Sedimentologica Sinica,2011,29(4):752-760. |
| |
| Authors: | XIAO Chuan-tao YI Xiao-wei LI Meng LI Chao |
| |
| Institution: | Key Lab of Exploration Technologies for Oil and Gas Resources(Yangtze University), Ministry of Education, Jingzhou, Hubei 434023 |
| |
| Abstract: | he Shamuluo Formation of Upper Jurassic in Dongqiao is mainly composed of a series of tidal flat and carbonate platform deposits and especially characterized by a lot of organic reefs. Reef building organisms are chiefly Stromatoproids, and secondly hexacorals. Among Stromatoporoids, there are different forms such as dendritic, cylindric and massive,which reflects the second prosperous period since the late Devonian recession during geological history. The reef building organisms mentioned above are the majority preservated at the original growth state, which all require warm, clean and normal shallow water environment with abundant light and better circulation. Through the study of individual ecology and analysis on the assemblage of reef building organisms, three reef building communities are recognized, namely Milleporidium Cladocoropsis, Cladocoropsis Milleporidium Milleporella and Milleporidium Actinatraea community.〓〓The analysis of sea level changes indicate that it exists three sea level change cycles of the reef bearing strata in the study areas, among them, the first cycles developed in the lower section of the Shamuluo Formation, namely clastic rocks Member; whereas the second cycle developed in the lower part of the second Member of Shamuluo Formation and sea level rising caused reef building organisms prosperous breeding such as stromatoproids to form the first prosperous period since the late Devonian recession and shaped the first building reefs community, namely Milleporidium Cladocoropsis community; the third sea level change occurs in the upper part of the second Member of Shamuluo Formation and shaped the second third term reefs resulting the development of the Cladocoropsis—Milleporidium—Milleporella community and Milleporidium—Actinatraea community. Replacement is the only form to the evolution of community，which is duo to the unstable of relative sea level changes during the sea level change peroid. It is due to the existing of the several subordinate cycles during the sea level change peroid that the reefs are characterized by discontinuous and little thickness.The decline of reefs in the area is mostly due to slow rising of sea level, resulting in the growth rate of accommodation was slower than the sediment accumulation, and showing by mostly sparry calcarenite of he reef covers.〓〓The authors hold that the existence of reef communities is of great significance for further studying Bangongcuo Nujiang suture zone merging time. They consider that oceanic crust subduction time of middle Bangongcuo Nujiang River suture zone(i.e. Dongqiao region of Anduo) should be in the late Jurassic or before the deposition of Shamuluo Formation of Late Jurassic (Shamuluo Formation is unconformably on the Late Jurassic hyperbasite) and after ultramafic rock Formation of the Late Jurassic. Because of the subduction, the study area was uplift as land and formed angular unconformity between Shamuluo Formation and the underlying Late Jurassic ultramafic rock. The existence of reef communities of Late Jurassic Shamuluo Formation showed that the study area may belong to a part of shallow continental shelf of the remaining back arc basin after Bangongcuo Nujiang River oceanic crust subduction. |
| |
| Keywords: | organic reefs paleoecology sea-level changes Late Jurassic Northern Tibet |
| 本文献已被 CNKI 万方数据 等数据库收录！ |
| 点击此处可从《沉积学报》浏览原始摘要信息 |
| 点击此处可从《沉积学报》下载免费的PDF全文 |
|
