Issue 3,2000 Table of Contents

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1 THE MIDDLE CRETACEOUS CALCAREOUS NANNOFOSSIL ZONES INGAMBA AREASOUTHERN XIZANG (TIBET)，CHINA ANDTHE CENOMANIAN-TURONIAN BOUNDARY

ZHONG Shi-Lan , ZHOU Zhi-Cheng , H.WILLEMS , ZHANG Bing-Gao , ZHU You-Hua

2000(3):313-323. CSTR:

[Abstract](6) [HTML](0) [PDF 526.76 K](369)

Abstract:
This study deals with calcareous nannofossils of mid-Cretaceous at Gamba Area in Southern Xizang （Tibet）China．The rock samples were collected from the Gamba Group of both Sections A and B．On the basis of the characteristicsediments the Gamba Group can be divided into three stratigraphic units from bottom to top namely the Gambadongshan Chaqiela and Gambacunkou formations．Calcareous nannofossils mainly appeared from the uppermost Gambadongshan Formation to Gambacunkou Formation．The preliminary results enable us to propose a detailed nannofossil zonation for the middleAlbian to the late Santonian．This zonation scheme consists of six zones and five addition biohorizons．The upper part of Gambacunkou Formation clearly exhibits a stratigraphic hiatus since the top of Quadrum gartneri zone （early Turonian） is immediately overlain by Lucianorhabdus cayeuxii zone （late Santonian）．The Cenomanian-Turonian boundary is discussed in detailon the basis of calcareous nannofossil data．The first occurrence of Gartnerago obliquum rather closely corresponds with thefirst appearance datum of Helvetoglobotruncana praehelvetica （foraminifera） thus that they are considered to be very usefulto determine the boundary between Cenomanian and Turonian in Southern Xizang （Tibet）．

2 THE JAW OF DATOUSAURUS BASHANENSIS DONG AND TANG, 1984

CAO You-Shu , YOU Hai-Lu

2000(3):391-394. CSTR:

[Abstract](7) [HTML](0) [PDF 248.31 K](245)

Abstract:
巴山酋龙 (Datousaurus bashanensis Dong and Tang ,1984)是四川盆地大山铺中侏罗世蜥脚类恐龙 ,亦称大头龙。其主要特征之一为硕壮的头骨。文中对保存于重庆自然博物馆的酋龙上下颌骨新材料进行较详细的记述。保存的前上颌骨长、高 (前端 )、厚分别为 120mm ,125mm和 40mm ;上颌骨长为 280mm ;下颌齿骨高为145mm。估计每侧上、下颌齿数分别为 14和 12枚。牙齿粗大 ,勺状 ,排列紧密。推测头骨长可达 6 7cm ,是已知蜥脚类恐龙中最硕大的。与大山铺同一地点其它蜥脚类相比 ,巴山酋龙的颌骨也不尽相同 ,这为进一步探讨其食性及古环境提供新的线索。