洛伊地区三叠系沉积体系特征及演化规律

The Sedimentary Characteristics and Evolution Law of Trassic,Luoyi District

洛伊地区三叠系沉积体系是近年来研究的重点,利用岩心、录井、测井及野外露头资料,并结合前人研究成果,对其进行分析.通过研究发现:洛伊地区三叠系沉积时期主要发育3种沉积体系类型,分别是曲流河沉积体系、三角洲沉积体系及湖泊沉积体系.中下三叠统主要发育曲流河沉积,上三叠统发育湖泊三角洲沉积,且从上三叠统沉积早期到晚期伴随着湖水面的上涨和湖盆面积的扩大.三叠系的沉积体系演化主要受控与中三叠世末印支运动的影响,印支运动造成扬子板块向华北板块俯冲,使洛伊地区周边隆起成山,并在洛伊地区形成深水湖盆.在对比洛伊地区与鄂尔多斯盆地上三叠统沉积特征及圈闭特征基础上,认为洛伊地区有较大的勘探潜力.洛伊地区沉积特征及演化规律的研究,为该地区未来的勘探提供了较为有利的地质依据.

By using the data of core, well logging and outcrop, the sedimentary characteristics and evolution law of Triassic system, Luoyi District are studied. It is found that there are three sedimentary facies including meandering river, delta and lacustrine developed in Triassic period. The middle and lower Triassic system mainly developed meandering river, while the upper Triassic system developed delta and lacustrine sedimentary facies along with the expansion of the lake area and the rising of the lake surface. The evolution law of sedimentary system is controlled by the Indosinian movement during middle Triassic. This movement caused the Yangtze plate to sub- duct to the North China plate, uplifted the surrounding of Luoyi District and made the sedimentary of deep-water lake in Luoyi District. By contrasting the sedimentary characteristics and stratigraphic trap of Luoyi District with those of Ordos basin, the exploration potential of Luoyi District is proved. The study of the sedimentary characteristics and evolution of Luoyi District provides more favorable geological evidences for the future exploration in the region.