辽西北票盆地中侏罗统海房沟组砾岩沉积特征与成因

通过对总长2 705 m两条剖面的实测、40块薄片鉴定、419个砾石统计及其粒度分析，确定了辽西地区北票盆地中侏罗统海房沟组砾岩的沉积特征及成因。研究表明：辽西北票盆地海房沟组主要岩性为一套冲积扇相的复成分砾岩，并夹一套喷溢相下部亚相安山质角砾熔岩和另一套爆发相空落亚相安山质角砾凝灰岩、热碎屑流亚相安山质角砾凝灰熔岩；海房沟组沉积物源来自研究区SSW向的太古宇变质岩及结晶基底和下侏罗统兴隆沟组火山岩的全面快速隆升剥蚀。结合构造背景，通过对北票组与海房沟组界线的研究和岩性岩相的鉴定，确定海房沟组冲积扇相的复成分砾岩是燕山运动二期挤压伸展构造运动的重要产物，两套中酸性火山岩的出现是两次火山喷发的重要标识。

Sedimentary Characteristics and Genesis of Middle Jurassic Conglomerates of Haifanggou Formation in Beipiao Basin,Western Liaoning

The sedimentary characteristics and genesis of the Middle Jurassic conglomerates in Haifanggou Formation were determined by measuring the 2 705 m long two sections,identifying 40 micro-sections,and analyzing 419 gravel statistical particle size in Beipiao basin in western Liaoning. The main lithology of Haifanggou Formation in the northwest Liaoning is a set of compound conglomerate which is an alluvial fan facies including two series of intermediate-acid volcanic rocks,namely the lower effusive facies,air-fall and pyro-clastic flow deposit of explosive facies. The source of Haifanggou Formation is from the SSW area,where the Archaean metamorphic rock, crystalline basement and the volcanic rocks of Xinglonggou Formation in the Lower Jurassic were generally rapidly uplift and denuded. Based on the study of the tectonic setting of the area, the boundary between Beipiao Formation and Haifanggou Formation and the sedimentary characteristics of Haifanggou Formation, the multicomponent conglomerate is an important product of the tectonic movement of compression and extension in the second phase of Yanshanian movement, and the two series of intermediate-acid volcanic rocks are the important indicators of volcanic eruption.