Discovery of the mid-Cretaceous sedimentary rocks from the ultrahigh-pressure terrane,Dabie Orogenic Belt,and its tectonopaleogeographic implications

作     者：Shuang-Ying Li Wei Xie Xin Wei Dong-Dong Yang Min Li Bo Hu Shuang-Ying Li;Wei Xie;Xin Wei;Dong-Dong Yang;Min Li;Bo Hu

作者机构：College of Resources and Environment EngineeringHefei University of TechnologyHefei 230009Anhui ProvinceChina Research Institute of Exploration and DevelopmentZhongyuan OilfieldPuyang 457001Henan ProvinceChina 

出 版 物：《Journal of Palaeogeography》 (古地理学报（英文版）)

年 卷 期：2023年第12卷第1期

页      面：153-177页

核心收录：

学科分类：070904[理学-构造地质学] 070903[理学-古生物学与地层学(含：古人类学)] 0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41772098,41172097) the China Geological Survey(Grant No.12120113094300) the Public Welfare Project of Geological Survey of Anhui Province,China(Grant Nos.2015-g-24,2014-g-9) 

主　　题：Zircon trace elements Zircon U-Pb geochronology Zircon Hf isotope Mid-Cretaceous sediments Provenance analysis Tectonic setting Sedimentary environment Dabie Orogenic Belt 

摘      要：The Dabie Orogenic Belt, located in east-central China, is known for the greatest outcrop area of the ultrahigh-pressure metamorphic rocks in the world and is typical for studying deep continental subduction and continent-continent collision. However, since lower-grade metamorphic rock occurrence in the core of the ultrahigh-pressure terrane was reported, it has become a new point of concern. This study reported new results. The so-called lower-grade metamorphic rocks are divided into sedimentary rocks and *** sedimentary rocks consist mainly of fine-grained turbidites formed under an anoxic deep-water lacustrine basin. Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry U-Pb detrital zircon dating indicates that their maximum deposit age is 119.0 ± 1.1 Ma belonging to the mid-Cretaceous Aptian. U-Pb detrital zircon ages from the sedimentary rocks cluster in three age groups: 1) 2773.8-1550.0 Ma(45.0%);2)868.8-622.3 Ma(23.0%);3) 147.0-100.0 Ma(31.5%). And the provenance and tectonic settings of these sedimentary rocks are discussed by synthesizing U-Pb detrital zircon ages, initial Hf isotope ratios, and trace elements of the zircons. Source rocks of the first group were mainly composed of the Paleoproterozoic basement derived from the reworking of the Paleoarchean-Neoarchean Yangtze continental crust. For the second group, its source rocks consisted of Neoproterozoic volcanics mainly from an island arc system, which derived from the reworking of older continental crust in the northern Yangtze Block. The third group’s source rocks were chiefly composed of Cretaceous rift igneous rocks derived from the derivation through melting of middle-aged continental crust in the Dabie Orogenic Belt. The meta-volcanics have weighted mean U-Pb ages from 751.0 ± 16 Ma to 786.3 ± 5.9 Ma, and their protoliths formed under a Middle Neoproterozoic island arc system in the northern Yangtze Block. The meta-volcanics underwent a Triassic subduction of different dep