Exhumation History and Preservation Degree of Yulong Porphyry Copper Deposit in East Xizang:Constrained by Thermochronology
Gan Shengtian
Sun Maoyu
Dong Leilei
Abstract：The Yulong porphyry copper deposit is the only super-large porphyry deposit in the Yulong porphyry copper belt,and the previous research on this deposit is primarily focused on genesis,with limited emphasis on the significance of post-metallogenic transformation in formulating prospecting strategies.Thermochronological methods such as zircon U-Pb,apatite fission track,apatite and zircon(U-Th)/He were employed to date and conduct related thermal history inverse modellings.The results indicate that the zircon U-Pb concordant age of the monzogranite porphyry of the Yulong deposit is(41.7±0.5)Ma,with zircon(U-Th)/He age ranging from 34.9 Ma to 39.3 Ma,indicating that the magmatic-hydrothermal evolution process of the Yulong deposit may have lasted at least 5 Ma.The apatite fission track ages range from 34.7 Ma to 19.7 Ma,while apatite(U-Th)/He ages range from 20.7 Ma to 18.4 Ma.These sequentially decreasing ages are indicative of the timing of cooling and exhumation events.The inverse thermal history modelling indicates that the Yulong deposit has undergone a roughly three-stage cooling process,combined with the regional tectonic evolution data,and the relatively rapid cooling between 34 Ma and 30 Ma may be related to the rapid uplift of the Qinghai-Xizang Plateau,resulting from the ongoing collision between the India and Eurasian continents during this period.The relatively slow cooling observed between 30 Ma and 21 Ma could be linked to the weakening collision activity.The relatively rapid cooling between 21 Ma and 14 Ma may be associated with the crustal thickening event in the North Qiangtang terrane,triggered by tectonic shortening or magma inflation during this period.Utilizing the thermal history simulation method,the exhumation amount of Yulong deposit is 3.45 km,Considering the 4-5 km of metallogenic depth of Yulong deposit,there is still 0.5-1.5 km of prospecting space in the deep part of the deposit.
Keywords：porphyry copper depositYulongdepositsuplift and exhumationgeochronologydeposit preservation
Publication Date：2025-11-30
Online Publishing Date：2025-12-15(First online date of this platform, not the publication date of the document)
Pages：21( 4208-4228 )