【摘要】 在藏南萨迦县赛区北部发育一套滑塌混杂沉积。对于这套混杂沉积的时代及地层归属,长期以来一直存有争议,主要原因是未能在其中获得足够的化石证据。本次工作在该套混杂岩中首次发现大量白垩纪放射虫化石,并建立4个放射虫组合:①Holocryptocaniumaff.barbui-Dictyomitraturris组合;②Acanthocircusdicrancanthos-Thanarlapulchra组合;③Thanarlaveneta-Pseudodictyomitrapseudomacrocephala组合;④Dictyomitramegnifica-Dictyomitratur-ritu组合。赛区“混杂岩”无论是古生物还是岩性组合特征,均可以与相邻地区的宗卓组进行对比,从而确认该套“混杂岩”属上白垩统宗卓组而非三叠系“修康群”。更多还原

【Abstract】 Olistostromic mélanges are distributed in the north of the Saiqu area,Sa’gya,southern Tibet.Due to the lack of enough fossil evidence,the age and stratigraphic assignment of the mélanges have long been controversial.Abundant Cretaceous radiolarian fossils have been discovered in the mélanges and four radiolarian assemblages are recognized:(1)Holocryptocanium aff.barbui-Dictyomitra turris assemblage,(2)Acanthocircus dicrancanthos-Thanarla pulchra assemblage,(3)Thanarla veneta-Pseudodictyomitra pseudo-macrocephala assemblage,and(4)Dictyomitra megnifica-Dictyomitra turritu assemblage.The mélange in Saiqu can be correlated with the Zongzhuo Formation in its neighboring areas whether in lithology or in fossil assemblage.Based on that,the“mélange”is ascribed to the Late Cretaceous Zongzhuo Formation rather than the Triassic“Xiukang”Group.更多还原