甘肃董湾晚新近纪地层及中新统/上新统界线  

LATE MIOCENE-EARLY PLIOCENE BIOSTRATIGRAPHY AND MIOCENE/PLIOCENE BOUNDARY IN THE DONGWAN SECTION,GANSU

作　　者：刘丽萍[1] 郑绍华[1] 张兆群[1] 王李花[1] 

机构地区：[1]中国科学院古脊椎动物与古人类研究所,脊椎动物进化系统学重点实验室,北京100044

出　　处：《古脊椎动物学报》2011年第2期229-240,共12页Vertebrata Palasiatica

基　　金：国家自然科学基金项目(编号:40872018);国家重点基础研究发展规划项目(编号:2006CB806400);中国科学院化石发掘与修理专项资助

摘　　要：古地磁测年表明,甘肃董湾晚新近纪剖面代表了7.3～3.5 Ma间的连续风成古土壤堆积。在74.8 m厚的剖面上,发现了小哺乳动物化石层位40个,共产出小哺乳动物39种。根据小哺乳动物组合特点,董湾剖面可以划分出4个生物地层带,Ⅰ+Ⅱ带为晚中新世晚期,相当于保德期;Ⅲ+Ⅳ带为上新世早期,相当于榆社期早期。中新统/上新统界线(5.33 Ma)位于剖面距顶部35.5 m处,比以鼢鼠Mesosiphneus最早出现为标志的生物地层Ⅲ带的底界低2 m。由于榆社阶底界直接对应于中新统/上新统界线,该剖面因其良好的地层和生物条件可被推荐为榆社阶界线层型的候选剖面。The Dongwan section is located near Dongwan Village,Qin'an County,Gansu Province (34°58′N,105°47′E).The section is a continuous eolian red clay sequence and is dated from 7.3 to 3.5 Ma by paleomagnetic study.The 74.8 m long section is divided into 21 layers(0 to 20)and 39 species of small mammals are found from 40 fossil levels.Based on faunal composition of small mammals,especially the myospalacines,four biozones are recognized. Biozone I covers layers 0~7,ranges magnetic polarities from upper part of C3Br.1n to the lower part of C3An.2n,and spans from 7.3 to 6.5 Ma.The mammals found in this biozone include Quyania chowi,Ochotonoma n.sp.1,O.primitiva,Ochotona minor,O.lagreli,Sicista sp.,Prospermophilus orientalis,Sinocricetus zdanskyi,? Kowalskia sp.,Prosiphneus licenti,P. tianzuensis,Lophocricetus grabaui,Pseudomeriones abbreviatus,and Hansdebruijnia pusillus. BiozoneⅡcovers layers 8～14.It ranges from the lower part of polarity zone C3An.2n to the base of C3n.4n,and has a time span from 6.5 to 5.24 Ma.The fossils found in this biozone include Sulimskia sp.,Parasoriculus sp.,Paenepetenyia cf.P.zhudingi,Ochotonoma n. sp.2,O.primitiva,Ochotona minor,O.gracilis,O.plicodenta,Prospermophilus orientalis, Sinocricetus zdanskyi,Prosiphneus eriksoni,Pliosiphneus lyratus,Chardina n.sp.,C.sinensis, Pseudomeriones abbreviatus,Sicista sp.,Apodemus sp.,Hansdebruijnia pusillus,Chardinomys sp.,and Allorattus sp.The beginning of biozoneⅡis marked by the first appearance of Prosiphneus eriksoni in the depth of 59 m. BiozoneⅢcovers layers 15～17,ranges from the base of C3n.4n to the upper part of C3n. 2n(Nunivak),and spans the time from 5.24 to 4.55 Ma.Fossils found in this biozone include Erinaceus sp.,Parasoriculus sp.,Ochotonoma n.sp.2,Ochotona minor,O.lingtaica,Trischizolagus mirificus,Sinotamias n.sp.,Sinocricetus zdanskyi,Cricetinus mesolophidus,Mimomys teilhardi, Pliosiphneus lyratus,Chardina sinensis,C.truncatus,Mesosiphneus sp.,Pseudomeriones abbreviatus,P.complicidens,Chardinomys sp.,C.yusheensis,and Apode

关 键 词：甘肃董湾 晚中新世-早上新世 生物地层 榆社阶 界线层型 

分 类 号：P534.62[天文地球—古生物学与地层学]