长垣坝构造带下三叠统嘉陵江组沉积相研究

长垣坝构造带嘉陵江时期为碳酸盐台地．发育开阔台地、局限台地和蒸发台地相．嘉一、嘉三期主要发育开阔台地相．嘉二、嘉四期主要发育局限台地和蒸发台地相。嘉一段至嘉二^1亚段广泛发育开阔台地灰泥质泻湖-灰质泻湖微相；嘉二^2-3亚段沿长垣坝构造带轴线及东部发育膏池／膏坪、云坪-云质局限泻湖微相．两侧发育灰质局限泻湖微相；嘉三^3至嘉四^1亚段颗粒滩微相范围略有缩小．云质泻湖明显扩大；嘉四^2-4亚段南部为膏质蒸发泻湖微相北部云质泻湖微相。

Study on Sedimentary Facies of Jialingjiang Formation of Early Triassic at Changyuanba Structure

Changyuanba structure belt in Southern Sichuan area was carbonate platform at Jialingjiang period of Lowe Triassic, open-platforms, localized mesa and evaporation-mesa were well developed. The first and third Jialingjiang periods are the open-platform developing periods, and the second and the fourth Jialingjiang period are localization-mesa and evaporation-mesa developing periods. Lime-mud or lime-lagoon microfacies are widely developed from the first Jialingjiang Group to the first subsegment of the second Jialingjiang Formation. Localized lagoon microfacies with gypsum pool/ plateau and dolomite pool/ plateau in east of the belt along the structure axis and limestone at both sides are developed at the second and third subsegments of the second Jialingjiang Formation from the third subsegment of the third Jialingjiang Formation to the first subsegment of the fourth Jialingjiang Formation , the range of granule beach is reduced but the dolomite lagune is obviously extended. From the second to fourth subsegments of the fourth Jialingjiang Formation, the gypsum evaporation lagoon in southern part and dolomite lagoon in the northern part are developed.