Ar-Ar and U-Pb ages of Hongshan copper deposit, Handan City, Hebei Province and their limitation on mineralization age

This paper is the result of mineral exploration engineering.

Objective Some copper and gold bodies have been found around Hongshan pluton in recent years. The determination of metallogenic age is the key to determine the genesis of ore deposits and analyze the metallogenic process.

Methods On the basis of detailed field geological work, the isotopic dating of zircon and copper-mineralized hydrothermal alteration mineral biotite in ore-hosting rocks were carried out by using U-Pb and ⁴⁰Ar-³⁹Ar stage heating methods, respectively.

Results Hydrothermal biotite alteration occurred at(127.62±0.5)Ma, the U-Pb ages of the zircons from ore-bearing rock are (130.45±0.94)Ma and (131.4±1.8) Ma, respectively.

Conclusions The results of age test show that copper mineralization is closely related to the acidic hydrothermal activity after the emplacement of fine-grained syenite porphyry. According to the planation surface of the southern Taihang mountain and the thickness of the cover layer of the rock mass, it is speculated that the Hongshan pluton has been denuded about 2000 meters due to crustal uplift, prospecting potential of the copper deposit is not promising.