摘要
近年来,四川盆地上三叠统须家河组(T3x)沉积学研究,有了突破—这个组多年来公认为陆相,现发现实为海相,即潮控河口湾和潮控三角洲成因。确定潮汐作用的独一无二的判据,是“双黏土层”。介绍它的研究进展,无疑对须家河组的勘探和研究有重要意义。展示T3x中常见沉积构造,突出了双黏土层。认识这种构造,起源于对荷兰西南部1个入潮口全新世水道沉积的研究。可以认出各个退潮、涨潮和滞水事件的特征。退潮堆积的交错层砂,其厚度呈正弦曲线变化,而滞水期形成的泥则呈对出现,是潮下环境的诊断性特征。一个实例被列举以说明如何编制潮汐韵律曲线。实际上使用的是更简明的直方图。全世界发现了许多精美的潮汐沉积剖面,得出了7种旋回曲线,详细介绍了半日旋回、朔望旋回和回归旋回,都是依据平衡潮汐理论解释的:地球在两半球反向潮胀中运行,潮汐受月相及月球在绕地轨道中倾斜和轨道距离变化所控制。这个理论很有用,但它过于简单而不能解释现实世界的潮汐。因此,简介了动力潮汐模式—依据潮汐成分(分潮)的调谐分析建立起来的模式。作为总结,建议四川盆地须家河组、鄂尔多斯盆地延长组,甚至中国东部中新生界的研究中都应注意潮汐作用的影响;当代沉积学应重视基础科学,以便更准确地解释中国古地理、古天文学讯息等。
In recent years, the study of the upper Triassic Xujiahe Formation (T3x) has made its breakthrough. This Formation which has been assigned to be continental deposits for many years now is discovered to be actually marine deposits, i.e. of the tide-dominated estuary and tide-dominated delta in origin. The unique criterion for tidal process is mud-layer couplets. Therefore, to introduce its research development is undoubtedly of importance to the Xujiahe Formation's exploration and researches. The primary discovery of the mud-layer couplets is induced the study of Holocene channel deposits in an inlet in Southwestern Holland in which features of the ebb, flood and slash–water events can be recognized. Thickness of the cross-bedded sands varies in a sigmoidal style, while the mud layers deposited during slash-water period occur in couplets. A special example is presented to indicate how to compile the tidal rhythmitic curves. However, the normal illustration is histogram plots. Many elegant tidal deposit cross sections have been discovered all over the world and seven cycle types have been affirmed. Among them, the Semidiurnal, Synodic and Tropical tidal cycles have been explained in detail on the basis of the equilibrium tidal theory. This equilibrium model explains tides in the context of changes in two hemisphere-opposite tidal bulges through which the Earth spins. The position and size of these tidal bugles relative to the Earth's equator is mainly controlled by the phases of the Moon and changes in declination and orbital distance of the Moon in its orbit around the Earth. This model is very useful, but it is too simple to explain the tides in the real world. Therefore, the basic understandings of the dynamic tidal model are needed to explain the real-world tides. This model is built around the concept of a harmonic analysis of the components that compose real-world tides. To sum up, it is recommended that tidal processes be taken into consideration for the studies of Xujiahe Formation in Sichuan Basin, Yanch
作者
赵霞飞
赵拓宇
张闻林
Zhao Xiafei;Zhao Tuoyu;Zhang Wenlin(Chengdu University of Technology, Chengdu, Sichuan 610059,China;China Petroleum Engineering & Construction Corporation, Southwest Company, Chengdu,Sichuan 610041,China;Exploration and Development Research Institute, PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan 610041,China)
出处
《天然气勘探与开发》
2019年第2期29-38,共10页
Natural Gas Exploration and Development
关键词
须家河组
双黏土层
潮汐韵律曲线
平衡潮汐理论
动力潮汐理论
中国中新生代地层
潮汐韵律岩
Xujiahe Formation
mud-clay couplet
tidal rhythmite curves
equilibrium tidal theories
dynamic tidal theories
the Mesozoic and Kainozoic of China
tidal rhythmites
