琼东南盆地古近纪泥炭沼泽破坏与重建作用对煤型源岩物质形成的控制

The control of Paleogene peat swamp destruction and reconstruction on the formation of coal-type source material in the Qiongdongnan Basin

李增学 刘莹 李晓静 张功成 孙瑞 王东东 尹露生 刘佳敏

Zengxue Li Ying Liu Xiaojing Li Gongcheng Zhang Rui Sun Dongdong Wang Lusheng Yin Jiamin Liu

煤系及煤层是重要的烃源岩类型，已引起广泛重视。以中国南海琼东南盆地为例，剖析泥炭沼泽破坏、重建作用与煤及陆源海相烃源岩形成的成因关系，归纳了泥炭沼泽破坏作用与泥炭物质形成和聚集的“源-汇系统”的特点。研究认为风暴事件是异地煤和陆源海相烃源岩形成的主要动力因素之一，并在此基础上建立了中国南海边缘海盆地泥炭风暴沉积模式。泥炭沼泽破坏和重建作用与泥炭物质的形成、分散及聚集过程是相互作用的关系，且具有复杂多变性；泥炭沼泽破坏作用使泥炭物质被大部或全部分解或搬运，而重建作用则是在适宜的气候条件下使泥炭沼泽发育的过程得以恢复；风暴事件是南海新生代盆地泥炭沼泽发生破坏作用以及泥炭物质被远距离搬运并沉积于海相环境的主要动力因素之一。风暴潮强烈地侵蚀和扰动滨岸带泥炭沼泽，导致大量泥炭碎屑物质被掀起而卷入海水中，经由风暴重力流和浊流搬运，最终沉积形成含有陆源海相有机质的烃源岩。

Coal systems and coal seams have been widely valued as an important type of hydrocarbon source rocks for oil and gas reservoirs. Taking the Qiongdongnan Basin of the South China Sea as an example， this study analyzes the genetic relationship between the destruction and reconstruction of peat swamps and terrigenous marine hydrocarbon source rocks， and summarizes the characteristics of the peat swamp destruction as well as the formation and accumulation of peat substances. It is suggested that storms are one of the main dynamic factors for the formation of different land coal and terrigenous marine hydrocarbon source rocks， and this leads to the proposition of a sedimentation mode for the peat storm in the edge of the South China Sea Basin. The results have shown that an unstable and complex interactive relationship exists between the destruction and reconstruction of peat swamps and the formation， decentralization and aggregation of peat substances. The destruction caused a full or partial decomposition and transportation of the peat substances， while the rebuilding restored the development of peat swamps under the suitable climatic conditions. Storms is behind all these destruction and long-distance transportation of peat substance in the swamps in the Cenozoic basins， South China Sea. With storms violently invading and disturbing the coastal peat swamps， large amount of peat clasts were rooted up and carried away by seawater， transported along with storm gravity flow and turbidity flow， and eventually deposited within source rocks as terrigenous marine organic matter.

10.11743/ogg20220603