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1、第20卷第3期现代地质Vol20No32006年9月GEOSCIENCESep2006一条新发现的奥陶系志留系界线剖面123苏文博,王永标,龚淑云(1中国地质大学地球科学与资源学院,北京100083;2中国地质大学地球科学学院,湖北武汉430074;3广东省深圳市地质局,广东深圳518031)摘要:在贵州省桐梓县红花园乡南坝子村发现一条新的穿越奥陶系志留系界线的地层剖面。该剖面自下而上依次出露有宝塔组、涧草沟组、五峰组和龙马溪组等,露头良好,产状平缓,化石丰富。其五峰组观音桥段顶部与龙马溪组交界处,即穿越奥陶系志留
2、系界线的一段地层,横向上可连续追索逾百米。自五峰组底部到龙马溪组底部(相当于Dicellograptuscomplanatus带Coronograptuscyphus带下部)的地层中已发现25层斑脱岩。根据生物地层、层序地层等资料初步确认了这些斑脱岩与湖北宜昌等地的斑脱岩具高分辨对比性。该剖面的发现为华南奥陶系志留系界线附近的各项研究提供了新的资料。关键词:界线剖面;奥陶系;志留系;华南中图分类号:P5344文献标识码:A文章编号:1000-8527(2006)03-0409-04ANewOrdovicianSilurian
3、BoundarySectioninGuizhou,SouthChina123SUWenbo,WANGYongbiao,GONGShuyun(1SchoolofEarthSciencesandResources,ChinaUniversityofGeosciences,Beijing100083,China;2FacultyofEarthSciences,ChinaUniversityofGeosciences,Wuhan,Hubei430074,China;3BureauofGeologyofShenzhen,Shenzhen,Gu
4、angdong518031,China)Abstract:Recently,anewOrdovicianSilurianboundarysectionhasbeendiscoveredatNanbazivillageoftheHonghuayuanTownship,TongziCounty,GuizhouProvince,SouthChina.Inthisperfectsection,theoutcropofthestratainterva,lwhichincludetheBaotaFm.,theJiancaogouFm.,andtheWufe
5、ngFm.,aswellastheLongmaxiFm.,inascendingorder,exposedprettywellwithlowdipdirectionofthebedsandabundantofvariousfossils.ThetransitionintervaloftheOrdovicianSilurianboundary,fromthetopoftheGuanyinqiaoMemberofWufengFm.throughintothelowermostLongmaxiFm.,canbetracedhorizontalyabo
6、utonehundredmeters.Moreover,25layersofKbentonitebedshavebeenrecognizedfromtheWufengFm.throughintothelowerpartofLongmaxiFm.Withthestudiesofbiostratigraphyandsequencestratigraphy,thepresentKbentonitebedshavebeendeterminedpreliminarilythattheycanbecorrelatedfairlywellinhighres
7、olutionwiththoseofinYichang,HubeiProvinceandotherareas.ThisnewsectionwillbeavaluablecluefortherelevantstudyfocusedontheOrdovicianSilurianboundaryinSouthChina.Keywords:boundarysection;Ordovician;Silurian;SouthChina北部四川南部一向不乏良好的地层剖面,引得0引言数代中外学者都在这个内陆地区留下了足迹。以作为上扬子地台稳定的台地相区之一
8、,贵州奥陶纪为例,十字铺页岩、湄潭页岩、桐收稿日期:20060502;改回日期:20060610;责任编辑:
