摘要
笔者运用现代沉积学和层序地层学理论,对陕西镇安西口地区二叠系—三叠系的主要不整合面和地质体的岩相岩石组合特征及空间展布规律进行调查,在此基础上并依据前人研究资料,将区内二叠系—三叠系划分为4个层序单位,进而对单位内的体系域系统进行了划分和研究,建立了该地区地层格架与地层模型。通过研究认为,4次大幅度海平面变化及区域构造沉降作用是形成4个Ⅱ型不整合面的根本原因。该地区自晚二叠世,在不同阶段的盆地演化过程中,皆继承了西浅东深的古地理格局。此项研究成果为在构造活动地带相对稳定地区进行地层格架与地层模型提供了范例。
The stratigraphic and sequence stratigraphic characteristics are examined for the Permian-Triassic strata in the Xikou region, Shaanxi in terms of modern sedimentological and sequence stratigraphic theories. The Permian-Triassic strata in the study area may be arranged into four sequence units. The systems tracts are divided on the basis of sequential architectures formed during sealevel rises and falls, and the stratigraphic framework and model are constructed for the Permian-Triassic strata in this area. The four phases of eustatic fluctuations and regional tectonic subsidence are responsible for the formation of four type2 unconformities. From the latest Early Permian onwards, the development of the basin during its formation and evolution displayed the palaeogeographic framework of being shallower in the western part and deeper in the eastern part of the basin. The results of research in this study may give a good example for the construction of the stratigraphic framework and model for the tectonically stable areas.
出处
《沉积与特提斯地质》
CAS
CSCD
2002年第4期44-49,共6页
Sedimentary Geology and Tethyan Geology
关键词
二叠系-三叠系
地层格架
地层模型
陕西
岩相古地理
沉积学
Xikou in Zhen'an
Permian-Triassic strata
stratigraphic framework
stratigraphic model
Shaanxi
