准噶尔盆地南缘郝家沟剖面下侏罗统八道湾组辫状河三角洲沉积

准噶尔盆地南缘郝家沟剖面下侏罗统八道湾组为一套典型的辫状河三角洲沉积，主要为砾岩、砂岩、细砂岩、粉砂岩和泥岩构成的一套碎屑岩沉积组合。八道湾组辫状河三角洲可以划分为辫状河三角洲平原、辫状河三角洲前缘和前辫状河三角洲3个亚相。进积型沉积序列和退积型沉积序列在八道湾组辫状河三角洲中都有发育，但以退积型沉积序列为主。八道湾组一段和二段构成一个长期基准面旋回SQ1，八道湾组三段与三工河组一段构成另一个长期基准面旋回SQ2。SQ1由3个中期旋回组成，每个中期旋回又由数量不等的短期旋回构成；SQ2可进一步划分为3个中期旋回。

Braided-river delta deposition of the Badaowan Formation of lower Jurassic in Haojiagou section, southern Junggar Basin

The Badaowan Formation of lower Jurassic in Haojiagou section,southern Junggar Basin,is a typical braided-river delta deposition.This section mainly consists of a clastic rock sedimentary association of conglomerate,sandstones,packsands,silts tones and mudstones.The braided-river delta of Badaowan Formation can be divided into three subfacies:braided-river delta plain subfacies,braided-river delta front subfacies and pro-braided-river delta subfacies.Progradational sequence and retrograding sequence both can be found in the braided-river delta deposition,but the retrograding sequence constitutes the majority.Members of No.1 and No.2 in Badaowan Formation make up of a long-term base-level cycle named SQ1,and members of No.3 of Badaowan Formation and No.1 of Sangonghe Formation make up of another long-term base-level cycle named SQ2.SQ1 can be divided into three mid-term cycles and each mid-term cycle can also be divided into different numbers of short-term cycles.SQ2 also can be further divided into three mid-term cycles.