| 义县组研究的新认识 |
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| 引用本文：邢德和,孙春林,孙跃武,张立东,彭艳东,陈树旺.2005.义县组研究的新认识[J].地球学报,26(1):25-30. |
| DOI：10.3975/cagsb.2005.01.05 |
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| 基金项目:中国地质调查局项目"K51E014004(北票市)等四幅1:5万区域地质调查"(编号:J4.1.12) |
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| 中文摘要:辽西地区义县组是一套中生代陆相火山-沉积岩系，主要由中-基性火山熔岩、火山碎屑岩及湖泊相(包含少量的河流相)沉积岩构成。依据火山活动的规律性，将义县组划分为4个岩性段，自下而上为：底砾岩 基性-中基性火山岩段；湖相沉积(或称珍稀化石层)岩 中性、酸性火山岩段；基性、中基性-酸性、偏碱性火山岩段和砾岩(包括沉火山角砾岩) 中酸性、偏碱性火山岩段。义县组中包含6个化石层位，其中义县组一段的底砾岩和基性、中基性火山岩的(沉)凝灰岩中产有丰富的以鹦鹉嘴龙为主的古脊椎动物化石；二段的湖相沉积岩中含有大量热河生物群化石，包括著名的中华龙鸟、孔子鸟和辽宁古果等珍稀化石，是义县组的最主要化石产出层位，且湖相化石层基本上为同一时期的产物。根据化石研究和同位素测定结果，将义县组的时代定为早白垩世。 |
| 中文关键词:义县组 地层 时代 辽西 |
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| New Knowledge on Yixian Formation |
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| Abstract:The Yixian Formation in western Liaoning Province comprises a set of Mesozoic continental volcanic-sedimentary rocks, which mainly consist of intermediate-basic volcanic lava, volcanic fragmental rock and lacustrine (including a little fluviatile) sedimentary rocks. The formation can be divided into four lithologic members based on the regularity of volcanic activity. From bottom to top, they are the first membei-the basal conglomerate and basic to intermediate basic volcanic member, the second member-the lacustrine sedimentary rock (or called the rare fossil layer) and acid-intermediate volcanic lithologic member, the third member-the basic, intermediate-basic, meta-alkaline volcanic member, and the fourth member-the conglomerate (including sedimentary volcanic breccia) and acid-intermediate, meta-alkaline volcanic member. There are 6 fossil layers in Yixian Formation. The basal conglomerate and basic, intermediate-basic volcanic sedimentary tuff in the first member contains abundant ancient vertebra fossils dominated by Psittacasaurus. The lacustrine sedimentary rock in the second member contains a large number of Jehol Biota fossils including the famous Sinosauropteryxprima, Confuciusornis sauctus and Archaefructus liaoningensis, thus serving as the chief fossils-bearing layer in Yixian Formation. Moreover, all the lacustrine fossil layers are synchronous. The age of Yixian Formation can be assigned to Early Cretaceous. |
| keywords:Yixian Formation stratigraphy age Western Liaoning |
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