欢迎访问《高校地质学报》官方网站,今天是
分享到:

J4

• 文章目录 • 上一篇    下一篇

层序地层中的混合沉积作用及其控制因素

李祥辉   

  1. 南京大学 地球科学系,南京 210093
  • 收稿日期:2008-09-20 修回日期:2008-09-20 出版日期:2008-09-20 发布日期:2008-09-20

Mixing of Siliciclastic-Carbonate Sediments within Systems Tracts of Depositional Sequences and Its Controlling Factors

LI Xiang-hui   

  1. Department of Earth Sciences, Nanjing University, Nanjing 210093, China
  • Received:2008-09-20 Revised:2008-09-20 Online:2008-09-20 Published:2008-09-20

摘要: 简要介绍了硅质碎屑与碳酸盐混合沉积有关概念及混合沉积作用类型,分析了层序体系域中的混合沉积作用及其控制因素。总结认为,硅质碎屑与碳酸盐的混合沉积作用不仅发生在低水位体系域(LST),而且其它各体系域中也都有不同程度的混合沉积现象,但混合沉积作用方式有差别:LST主要为源区混合,陆棚边缘体系域(SMT)和高水位体系域(HST)晚期以间断混合及相混合占优,海浸体系域(TST)早期以间断混合为主。综合研究显示,准层序一级的海平面变化型式差异可能是导致层序体系域混合沉积作用的主要因素,其中,LST、SMT、晚期HST的混合沉积作用分别与准层序一级海平面变化的幅度、速率、位置和持续时间有关,TST则受控于物源供给;先期地形、气候变化(含碳酸盐生产速率影响)或多或少对体系域的混合沉积作用有影响。此外,某些情况下层序体系域的混合沉积作用可能会受到局部构造活动影响,而层序组或超层序内层序体系域的混合沉积作用强弱及其旋回性变化可以提供脉动性区域构造活动信息。

Abstract: Mixing of siliciclastic and carbonate sediment is widespread in variable marine sedimentary environments through the Phanerozoic. Terminology of mixing and its classification are introduced in the paper, and the controlling factors upon mixing within systems tracts of depositional sequences are discussed. In general, the punctuated mixing is the most ordinary sedimentation in all systems tracts of mixed depositional sequences, and the source mixing associated with a little facies and punctuated mixing occurs within lowstand systems tract (LST); the facies and punctuated mixing becomes the main sedimentation in the shelf marginal systems tract (SMT) and the late highstand systems tract (HST); and the transgressive systems tract (TST) is characterized by the punctuated mixing with a little facies mixing. It is proposed that the mixing within systems tracts of depositional sequences is chiefly constrained by the patterns of the sea-level changes, i.e., the mixing within LST, SMT and late HST could be induced by amplitude, rate, and time duration of sea-level changes, and the mixing within TST could be related to the source supply. The mixing could be more or less influenced by the former topography and carbonate production in moderate paleoclimate. Fuether more, the regional tectonic activities might be partially responsible for mixing, which means that the cycles of mixing procession within systems tracts of depositional sequences in a sequence set or supersequence could be responses of vpulse regional tectonic activities.