新疆巴里坤下泥盆统大南湖组的厘定与生物地层分析

依据岩性、岩相及古生物等资料,将新疆巴里坤一带的一套早泥盆世地层厘定为下泥盆统大南湖组,并可分为下上两部分:下部以沉积碎屑岩为主,上部以火山岩和火山碎屑岩为主;从阿也尔苏剖面中采集到的Atrypa、Ca marotoechia、Howellella、Megastrophia和Leptaenopyxis等腕足化石,可与准噶尔盆地西部下泥盆统顶部的芒克鲁组、东部下泥盆统托让格库都克组等地层对比,化石组合呈现早泥盆世晚期(埃姆斯期)特征。生物地理区系分析认为,该地腕足动物同新疆北部准噶尔、东北北部、内蒙古等地同属老世界大区的巴尔喀什-蒙古-鄂霍茨克区。通过生物地层的分析,使研究区该组地质时代有了确切的化石依据,有利于该地泥盆纪地层层序的厘定和地层格架的完善。

Redefinition of Dananhu Formation and Research on Its Biostratigraphy in Balikun,Xinjiang

Based on lithology, facies and fossils, the strata lying northern Sandaoling area was definited as Dananhu Formation.The brachiopod fossils found in the Formation(D1d), such as Leptaenopyxis,Megakozlowskiellina,Megastrophia and Leptoslrophia,are most similar to those which found in the Mangkelu Formation, Tuoranggekudouke Formation, the stratotype of the Dananhu Formation in Hami, so the geological age of Dananhu Formation in the research area should be Emsian Period in Early Devonian;Its Zoogeography belongs to the Balkhash-Mongolia-Okhotsk Region of the Old World Realm (Devonian).