Late Cretaceous Foraminiferal Faunas from the Saiqu ＂mélange＂ in Southern Tibet

: As one of the melanges in the southern side of the Yarlung-Zangbo suture zone, the Saiqu melange in southern Tibet is important for understanding the evolution of the Neo-Tethys ocean. The age of the Saiqu melange, however, has been debated due to the lack of reliable fossil evidence in matrix strata. Based on lithological similarities with platform strata in southern Tibet and limited fossils from exotic blocks, previous studies variously ascribed the Saiqu melange to be Triassic in general, Late Triassic, or Late Cretaceous. Here we reported planktonic foraminiferal faunas from the matrix strata of the Saiqu melange. The new fossils yield a Late Cretaceous age, which is so far the best age constraint for the melange. Regional stratigraphic correlation indicates that the Cretaceous Oceanic Red Beds (CORBs) in Saiqu may be time equivalent to the CORBs of the Zongzhuo Formation in neighboring regions. Thus the Saiqu melange should be correlated to the Upper Cretaceous Zongzhuo Formation rather than the Triassic Xiukang Group, as previously suggested.