华南东部晚古生代岩相古地理及构造指示意义【华南古大陆演化及其资源环境效应”专辑】
- 收稿日期:
2024-01-15
- 网络出版日期:
2024-09-03
摘要: 【目的】经历过早古生代武夷-云开造山运动后,华南东部进入晚古生代构造平静期,区域内发生大范围海侵事件并沉积了厚层的上古生界沉积序列。其中,泥盆系-下二叠统空谷阶的地层厚度展布、岩相横向变化等特征对了解华南东部在武夷-云开造山垮塌后的古地貌继承、晚古生代盆地沉降、海平面变化等方面有重要意义。【方法】我们对区内泥盆纪-早二叠世空谷期地层进行厚度和岩性统计,分别编制了早泥盆世、中泥盆世、晚泥盆世、早石炭世、晚石炭世-早二叠世萨克马尔期、早二叠世亚丁斯克期-空谷期的地层等厚图和平面岩相图,并计算各世期的盆地沉降速率。【结果】结果表明,武夷-云开造山垮塌之后,华南晚古生代盆地的形成与演化可分为两个阶段。第一阶段发生在泥盆纪时期,华南东部呈东北高、西南低的地势特征,盆地沉降速率大(约25 m/Ma)。第二阶段发生在石炭纪-早二叠世空谷期,构造活动趋于平静,盆地大范围接受海侵,盆地沉降速率小(约10 m/Ma)。【结论】结合华南东部泥盆纪大型正断层的展布规律和活动,晚古生代盆地发生第一阶段沉降主要受控于构造活动,其构造活动机制主要来源于武夷-云开造山垮塌,并且与华南板块从冈瓦纳大陆裂离所产生的拉张作用也有一定关联。盆地发生第二阶段沉降主要受控于沉积物负载和气候变化,且晚泥盆世-早石炭世气候变化对盆地沉降的影响较大。
The late Paleozoic lithofacies paleogeography and tectonic-sedimentary evolution of the eastern South China
- Received Date:
2024-01-15
- Available Online:
2024-09-03
Abstract: [Objectives] After the early Paleozoic Wuyi-Yunkai orogeny, the eastern South China went into a tectonic quiescence period during the late Paleozoic, with large-scale marine transgression and think sedimentary strata accumulation. Specifically, nature of the lower Devonian to lower Permian (the Kungurian stage) strata, such as isopach change of strata, lateral variation of lithofacies, are important to understand the post-orogenic topography of the eastern South China. [Methods] We collected stratigraphic thicknesses and lithological data of the lower Devonian to lower Permian (the Kungurian stage) strata in the eastern South China, compiled strata isopach maps and lithofacies maps of six main stages, including the early Devonian, the middle Devonian, the late Devonian, the early Carboniferous, the late Carboniferous to early Permian (the Sakmarian stage), and the early Permian (the Artinskian and Kungurian stages). The tectonic subsidence rate of the basin at five different localities in each stage was calculated. [Results] The results show that the subsidence of the late Paleozoic basin of the eastern South China can be divided into two stages. The first stage was the Devonian with a high subsidence rate (about 25 m/Ma). The second stage was the Carboniferous to early Permian (the Kungurian stage) with a low subsidence rate (about 10 m/Ma). [Conclusions] Taking the regional widely-distributed and large-scaled normal faults into consideration, it speculates that the first stage of basin subsidence was mainly controlled by tectonic activities, which was inherited from the post-Wuyi-Yunkai orogenic collapse and possibly the drifting-away of South China from the Gondwana during the Devonian. The second stage of basin subsidence was controlled by the icehouse climate and sediment load of the baisn during the Carboniferous to early Permian.