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义县组是一套中生代火山-沉积地层,含有丰富的以热河生物群为代表的生物化石.20世纪80年代以来,在义县组沉积夹层中陆续发现珍稀鸟类、小型兽脚类恐龙中华龙鸟,以及原始被子植物辽宁古果等珍稀化石,但是有关珍稀化石沉积层的空间分布、上下层位关系、沉积环境和时代归属等问题,一直悬而未决,中国地质调查局东北地区地调中心从1999年10月开始,对辽宁省北票市-义县之间的义县组进行了1∶5万区域地质调查填图,不仅确定了珍稀化石沉积层在地层层序中的确切位置,而且在珍稀化石沉积层以下,即义县组底部发现了大量恐龙化石.1恐龙化石产出层位及环境特征新发现的恐龙化石产地主要分布在北票市上园地区的水泉沟、陆家屯、跑达沟、新立屯、达子营、马代沟和六台等地.这些化石产在义县组的底砾岩层和基性-中基性火山岩的爆发-沉积相夹层中.2001年张立东、郭胜哲、丁秋红等发表的论文将义县组划分为6个岩性段.进一步工作表明此6个岩性段的总层序是对的,但原第四段地层是一个复合体,一部分(万佛堂的酸性火山岩)应当归入六段以上的层位,余下的酸性火山碎屑岩(如黄半吉沟顶部酸性岩)确实属于原四段层位.根据最新的地质调查研究结果,我们对北票地区的义县组岩性段做了进一步归并,自下而上划分4个岩性段,特征如下:一段:?
The Yixian Formation is a set of Mesozoic volcanic-sedimentary formations, which are rich in biological fossils represented by the Jehol Biota. Since the 1980s, rare birds, small tortoises Chinese Dragonbird, and the original angiosperms Liaoning ancient fruit and other rare fossils, but the spatial distribution of rare fossil deposits, the relationship between the upper and lower strata, sedimentary environment and the ownership of the times and other issues, has been pending, the Geological Survey of Northeast China Geological Survey Center Starting from October 1999, a 1: 50000 regional geological mapping survey was conducted on Yixian formation between Beipiao-Yixian County in Liaoning Province. It not only confirmed the exact location of the rare fossil sedimentary layer in the stratigraphic sequence, Moreover, a large number of dinosaur fossils have been found below the rare fossil sediments, ie, at the bottom of the Yixian Formation.1 Production Horizons and Environmental Characteristics of Dinosaur Fossils The newly discovered dinosaur fossils are mainly distributed in Shuiquangou, Lujiatun, Pagoda, Xinlitun, Tatsuying, Maadiou and Liutai etc. These fossils are produced in the interbedded sedimentary facies of the base conglomerate and basic-base volcanic rocks in the Yixian Formation. The paper published in Zhang Lidong, Guo Shengzhe and Ding Qiuhong et al. Divides the Yixian Formation into six lithologic sections in a year, and further work shows that the total sequence of the six lithologic sections is correct, but the original fourth section is a complex , Part of the acid volcanic rocks of Wanfo Hall should be classified into more than six layers, and the remaining acidic pyroclastic rocks (such as the top of the Huangbangyi ditch) do belong to the original four-layer strata. According to the latest geological survey results , We further merge the lithology of the Yixian Formation in the Beipiao area and classify four lithologic sections from bottom to top. The characteristics are as follows: