浙赣地区上奥陶统砚瓦山组的牙形刺及其地层意义(英文)  

UPPER ORDOVICIAN CONODONTS FROM THE YENWASHAN FORMATION IN THE ZHEJIANG-JIANGXI BORDER REGION,S.E.CHINA AND THEIR BIOSTRATIGRAPHIC SIGNIFICANCE

作　　者：王志浩[1] 伯格斯特龙 张元动[1,3] 甄勇毅 吴荣昌[1,3] 

机构地区：[1]中国科学院南京地质古生物研究所,南京210008 [2]美国俄亥俄州大学地球历史部地球科学学院,美国俄亥俄州哥伦布43210 [3]中国科学院资源地层学与古地理学重点实验室,南京210008 [4]澳大利亚新南威尔士州地质调查所,澳大利亚悉尼

出　　处：《古生物学报》2015年第2期147-157,共11页Acta Palaeontologica Sinica

基　　金：国家基金委创新研究群体项目(批准号:41221001,41290260);国家自然科学基金(41172034)资助;IGCP591项目“早、中古生代重大事件”的阶段成果

摘　　要：描述产自浙江常山205国道剖面上奥陶统砚瓦山组的牙形刺,主要有Baltoniodus alobatus,B.variabilis,Periodon aculeatus,Dapsilodus viruensis,Scabbardella altipes和Panderodus gracilis等,可归入Baltoniodus alobatus带。浙赣地区奥陶系砚瓦山组自建立以来都被归入瀚江期,并与宝塔组对比。本文根据当前的发现并结合以前报道的砚瓦山组牙形刺化石,认为砚瓦山组自下而上可识别出Pygodus anserinus,Baltoniodus alobatus和Hamarodus brevirameus(=Hamarodus europaeus)等带,其时代应归为桑比早期至凯迪早期,并可与华南扬子区的庙坡组大部(或大田坝组)至宝塔组对比。其中,Pygodus anserinus带和Baltoniodus alobatus带见于浙江常山、江山地区,Hamarodus brevirameus带则见于江西武宁。在常山黄泥塘金钉子剖面,砚瓦山组底部为Pygodus anserinus带;在常山205国道剖面则见Baltoniodus alobatus带;但在江西武宁地区,砚瓦山组从底部起,几乎全都归为Hamarodus brevirameus带。因而,砚瓦山组在江西武宁与浙江常山等地之底界并不一致,有明显的穿时现象。本文牙形刺生物地层研究还表明,晚奥陶世古滕贝格的δ13 C的正偏移事件(GICE)在常山地区的起始时间不会早于B.alobatus带。A small conodont fauna from the Upper Ordovician Yenwashan Formation exposed at a road-cut along Highway 205 near Changshan,western Zhejiang includes Baltoniodus alobatus,B.variabilis,Dapsilodus viruensis,Panderodus gracilis,Periodon aculeatus and Scabbardella altipes and is referred to the Chinese Baltoniodus alobatus Zone.Based on the present study,and on the conodont faunas previously described from the unit,the YenwashanFormation in its most complete stratigraphical range contains conodonts of the Pygodus anserinus,Baltoniodus alobatus,and Hamarodus brevirameus（formerly Hamarodus europaeus）zones and ranges from the early Sandbian to the early Katian.It can be correlated with most of the Miaopo Formation（or the equivalent Datianba Formation）and the Pagoda Formation.Both biostratigraphic and chemostratigraphic data indicate that the base of the Yenwashan Formation is diachronous and occupies a different stratigraphic level in different distribution areas of the formation.The present investigation is of special interest in showing that the beginning of the Guttenbergδ13 C excursion（GICE）is not older than the B.alobatus Zone in the study area.

关 键 词：牙形刺 地层对比 化学地层学 砚瓦山组 奥陶系 浙赣地区 

分 类 号：Q915[天文地球—古生物学与地层学]