辽宁兴城龙回头盆地海房沟组地层序列及沉积环境研究

Stratigraphic Sequence and Sedimentary Environment of the Haifanggou Formation in the Longhuitou Basin of Xingcheng,Liaoning Province

龙回头盆地是位于辽宁省葫芦岛南的小型中生代盆地,盆地内充填中侏罗统海房沟组,本文以研究盆地内海房沟组地层序列及沉积环境为目的,在盆地内进行实测剖面、砾岩成分统计、砾岩粒径统计、砂岩粒度分析等工作,在海房沟组内发现植物化石(Podozamitaceae gen.indet.)及煤线,认为盆地内海房沟组与锦西南票盘道沟海房沟组及北票海房沟村海房沟组岩石地层序列可以对比。对砾岩的研究结果表明,盆地内砾岩普遍具有短距离搬运、快速堆积的特点,并通过分析剖面内砾岩、砂岩、粉砂岩及泥岩的岩石组合特征,认为盆地内海房沟组属山前盆地冲积扇相。

The Longhuitou basin is a small Mesozoic basin located in the south of Huludao city in Liaoning Province, with the Middle Jurassic Haifang- gnu Formation filling. The stratigraphic sequence and sedimentary environment of the Haifanggou Formation are studied in this paper using several methods including stratigraphic measurements, composition statistics and particle size statistics of the conglomerate, and sand grain size analysis. Plant fossil of Podozamitaceae gen. indet, and coal streak are found in the fine grained beds of the Haifanggou Formation. It is suggested that the lithostratigraphic se- quence of the Haifanggou Formation in the Longhuitou basin,the Pandaogou of Nanpiao and the Haifanggou village of Beipiao are comparable. The result shows that the conglomerates were generated through short-distance transported and rapid accumulation. A synthetic analysis of the conglomerate, sand- stone, siltstone and mudstone in the sections indicates that the Haifanggou Formation in this basin is alluvial fan face of a piedmont basin.