Exhumation and Preservation of the Jinchuan Ni-Cu-PGE Deposit under the East Longshou Mountain Thermal Evolution,Revealed by Apatite Fission Track Thermochronology  

作　　者：LEI Xianghe YU Qiang JIAO Jiangang LIU Jian SUN Xianyao HE Lijuan YANG Qike 

机构地区：[1]School of Earth Science and Resources,Chang'an University,Xi'an 710054,China [2]Key Laboratory of Western China's Mineral Resources and Geological Engineering,Ministry of Education,Chang'an University,Xi'an 710054,China [3]Xi'an Key Laboratory for Mineralization and Efficient Utilization of Critical Metals,Xi'an 710054,China [4]Department of Geology,Northwest University,Xi'an 710069,China

出　　处：《Acta Geologica Sinica(English Edition)》2023年第2期486-500,共15页地质学报（英文版）

基　　金：jointly funded by the National Natural Science Foundation Project(Grant No.92162213);The Fundamental Research Funds for the Central Universities,CHD(Grant No.300102272205)。

摘　　要：Uplift and exhumation are important factors affecting the preservation of deposits.The anatomy of uplift-cooling evolution and exhumation in the East Longshou Mountain is of significant research value in understanding changes in the Jinchuan Ni-Cu-PGE deposit since its formation.This study uses apatite fission track(AFT)thermochronology to reconstruct the thermal history of the East Longshou Mountain,including the Jinchuan mine,revealing the uplift and exhumation history of the East Longshou Mountain and elucidating the preservation status of the Jinchuan deposit.The AFT ages in the East Longshou Mountain are distributed from 62.3±3.0 Ma to 214.7±14 Ma,with significant differences in ages in distinct areas,the central and pooled ages being consistent within the margin of error.Inverse thermal history models reveal two rapid cooling events associated with exhumation from the Early Jurassic to the Early Cretaceous(200–100 Ma)and since the Miocene(15–0 Ma),the former attributable to the far-afield response to the closure of the PaleoTethys Ocean and plate assembly at the southern margin of Eurasia,the latter associated with the initial India-Eurasia plate collision.A slow cooling event from the Early Cretaceous to the Miocene(100–15 Ma)is thought to be related to the arid environment in northwest China since the Cretaceous.These cooling events have diverse responses and cooling rates in different blocks of the East Longshou Mountain:the southwest and centre of which are mainly cooled over 200–120 Ma and 120–0 Ma,with cooling rates of~0.25 and~0.33°C/Ma(~1.25 and~0.33°C/Ma in the centre);the Jinchuan mine primarily cooled over 160–100 Ma,100–15 Ma and 15–0 Ma,with cooling rates of~1.33,~0.25 and~2.00°C/Ma.These differentiated coolings imply that the uplift of the East Longshou Mountain before the Miocene(~15 Ma)was integral.Strong uplift then occurred in the vicinity of the mining area,which is a critical period for the uplift of the Jinchuan deposit to the surface,meaning that the Jinchuan depos

关 键 词：apatite fission track deposit preservation uplift-cooling Jinchuan Ni-Cu-PGE Deposit East Longshou Mountain 

分 类 号：P618.2[天文地球—矿床学]