The discovery of Late Triassic hypabyssal mafic dykes in the Huozhou complex and their geological significance:Evidence from petrology,geochemistry,and geochronology  

作　　者：Haiyan Liu Chong Peng 

机构地区：[1]College of Geographical Sciences,Shanxi Normal University,Taiyuan 030031,China [2]Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China [3]School of GeoSciences,University of Edinburgh,Edinburgh EH93JW,UK

出　　处：《Acta Geochimica》2024年第6期1013-1036,共24页地球化学学报（英文）

基　　金：the 2023 Shanxi Province Higher Education Science and Technology Innovation Project(award number 2023L161);the Science and Technology Department of Shanxi Province(award number 202303021212158);the open fund from the Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources;Institute of Geology;Chinese Academy of Geological Sciences(award number J1901-16);the teaching reform project“Geographic Modeling,Simulation and Visualization”established by Shanxi Normal University(award number 2019JGXM-39);“The Research Start-up Fund of Shanxi Normal University for Dr.Peng Chong in 2016”(award number 0505/02070438);“The Research Start-up Fund of Shanxi Normal University for Dr.Liu Haiyan in 2017”(award numberumber 0505/02070458);“The Research Fund for Outstanding Doctor in 2017”(award number 0503/02010168),established by the Education Department of Shanxi Province for Dr.Liu Haiyan。

摘　　要：The Huozhou complex in the Trans-North China Orogen exhibits two events of mafic magmatism(separated by ca.700 Ma):Neoproterozoic(920±15 Ma)Shimenyu diabase and Late Triassic(217±2.5 Ma)Xingtangsi diabase.Investigations have focused on systematic petrology,zircon U-Pb dating,Lu-Hf isotopes,and lithogeochemistry.The research findings indicate that the Late Triassic Xingtangsi diabase of the Huozhou complex can be classified as a transitional type between intermediate and mafic rocks based on their SiO_(2)content.This classification is supported by an average SiO_(2)content of 53.94%,ranging from 53.33%to 54.28%.In the Zr/TiO_(2)vs.Ce diagram,all samples lie within the range of basalt.The zircons from the Late Triassic Xingtangsi diabase have lowε_(Hf)(t)values ranging from-12.7 to-8.7,with an average of-11.1.Additionally,the single-stage model age T_(DM1)is estimated to be between 1207 and 1701 Ma.These findings suggest that the magma responsible for the dyke originated from either partial melting or an enriched mantle source inside the Meso-Proterozoic lithospheric mantle.The elevated concentrations of Th(thorium)and LREEs(light rare earth elements),as well as the Th/Yb and Th/Nb ratios,suggest the potential incorporation of subducted sediments within the magma source region.The rock displays negative Nb,Ta,Zr,Hf,and Ti anomalies.These geochemical attributes align with the distinctive traits observed in volcanic rocks found within island arcs.The formation of the Late Triassic Xingtangsi diabase is likely associated with the geological context of an arc setting,which arises from the collision between the Yangtze plate and the North China Craton.

关 键 词：Trans-North China Orogen Huozhou complex GEOCHEMISTRY Hf isotope North China Craton 

分 类 号：P534.51[天文地球—古生物学与地层学] P588.124[天文地球—地质学]