资源描述：
《辽西义县组叶肢介化石在冀北滦平盆地西瓜园组中的系统发现及其意义》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。
1、Vol.27,No.6Jun.,2008第27卷第6期2008年6月地质通报GEOLOGICALBULLETINOFCHINA辽西义县组叶肢介化石在冀北滦平盆地西瓜园组中的系统发现及其意义牛绍武1,田树刚2NIUShao-wu1,TIANShu-gang21.中国地质调查局天津地质矿产研究所,天津300170;2.中国地质科学院地质研究所,北京1000371.TianjinInstituteofGeologyandMineralResources,ChinaGeologicalSurvey,Tianjin30017
2、0,China;2.InstituteofGeology,ChineseAcademyofGeologicalSciences,Beijing100037,China摘要:冀北滦平县西瓜园南李营剖面是西瓜园组的命名剖面,自下而上可划分为西瓜园组一至四段,为一套单一岩相的沉积岩。在火斗山乡马圈子,西瓜园组以一层水下分流河道砾岩与其下伏大店子组四段为连续沉积,拉海沟马圈子剖面为西瓜园组与大店子组的界线层型。西瓜园组自下而上可连续划分为5个叶肢介化石带,与辽西义县组尖山沟层、老公沟层-金刚山层的叶肢介组合完全可以对比,义
3、县阶的单位层型应以西瓜园组为层型剖面,原定义县阶的单位层型马神庙-宋八户标准地层剖面仅能作为义县阶的副层型。由于辽西义县组尖山沟层至金刚山层的叶肢介化石在冀北西瓜园组中的系统发现,冀北地区西瓜园组与辽西义县组完全可以对比,从而解决了30余年来冀北辽西晚期中生代地层的对比问题,具有重要的地层意义。关键词:冀北滦平盆地;西瓜园组;叶肢介;辽西;义县组中图分类号:P534.53;Q915文献标志码:A文章编号:1671-2552(2008)06-0753-16NiuSW,TianSG.Discoveryofconchos
4、tracansoccurringintheYixianFormationofwesternLiaoningintheXiguayuanFormationoftheLuanpingbasin,northernHebei,China,anditssignificance.GeologicalBulletinofChina,2008,27(6):753-768Abstract:TheLiyingsectioninthesouthofXiguayuan,LuanpingCounty,northernHebei,isthen
5、amingsectionoftheXiguayuanFormation.Thisformationmaybedividedinascendingorderintofourmembersandconsistsofsedimentaryrocksofmonotonousrockfacies.AtMajuanzi,HuodoushanTownship,abedofsubaqueousdistributarychannelconglomerateoftheformationwasde-positedcontinuously
6、withitsunderlyingDadianziFormation,andtheMajuanzisectionofLahaigouistheboundarystratotypeoftheXiguayuanFormationandDadianziFormation.AbundantconchostracanfossilswerefoundintheXiguayuanFormationofthissection,including5generaand7species.Fromthebaseupward,theXigu
7、ayuanFormationisdividedintofiveconchostracanzones,whichcanbecompletelycorrelatedwiththeconchostracanassemblagesoftheJianshangoubed,LaogonggoubedandJingangshanbedoftheYixianFormationinwesternLiaoning.TheunitstratotypeoftheYixianStagetakestheXiguayuanFormationas
8、itsstratotypesection,andtheMashenmiao-Songbahustandardstratigraphicsection—theunitstratotypeoftheoriginalYixianStage—canonlyserveasaparastratotypeoftheYixianStage.Astheconchostraca
