川南丹凤—塘河地区嘉陵江组沉积环境分析

通过对泸州古隆起丹凤—塘河地区嘉陵江组的岩心观察和岩石薄片鉴定,及对该区岩石类型组合、古生物化石、沉积结构、沉积构造和沉积序列等沉积相标志的详细研究,将嘉陵江组划分为开阔台地、局限台地2个沉积相,并进一步划分出5个亚相及若干微相。在此基础上,研究了嘉陵江组沉积相空间展布特征,并对其沉积环境及演化进行了分析,认为嘉陵江组碳酸盐岩发生了较为频繁的海平面升降变化,主要经历了6个阶段的演化过程,形成了3次较大的海进→海退沉积旋回,每一旋回又由多个次一级小旋回组成,而小旋回中又由多个小韵律组成。在对研究区岩性、沉积环境详细研究后认为:塘河构造及丹凤场构造的嘉一段—嘉二1亚段、塘河构造及临峰场构造的嘉二3亚段是浅滩颗粒云岩和滩间云岩发育的主要层位。

Sedimentary environment of Jialingjiang Formation in Danfeng-Tanghe area,southern Sichuan Basin

Based on core observation and rock slice identification, combined with the studies on the combination of rock types,fossils,sedimentary texture, sedimentary structure and sedimentary sequence, the Jialingjiang Formation in Danfengchang-Tanghe area is divided into two sedimentary facies including open platform and restricted platform, and further divided into five subfacies and several microfacies. The distribution of sedimentary facies of Jialingjiang Formation was studied, and the sedimentary environment and its evolution were analyzed. It is considered that the carbonate rocks of Jialingjiang Formation has frequent sea-level changes, experienced six evolution stages,and formed three times of larger transgression-regression sedimentary cycle. Each cycle is composed of small subcycles, while small subcycle is composed by a number of little rhythms. After detailed study on the lithology and sedimentary environment, it is considered that the most favorable layers for shallow particles dolomite and beach room dolomite are Jia Ⅰ-Jia Ⅱ1 member of Jialingjiang Formation in Tanghe and Danfengchang area and Jia Ⅱ3 member in Tanghe and Linfengchang area.