Abstract:

There are diverse metallogenic ages of Haigou gold deposit, a large low-sulfide quartz vein type gold deposit, which restrict studying on genesis and ore prospecting of it. With ⁴⁰Ar/³⁹Ar laser probe dating of fluid inclusions in quartzs, the authors present an isochron ⁴⁰Ar/³⁹Ar age (170±20) Ma (MSWD=0.31)and an inverse one (172±16) Ma (MSWD=0.35) of fluid inclusions in quartzS formed in major metallogenetic stage, and ⁴⁰Ar/³⁶Ar ratios are 298±4 and 299 ± 4 respectively. Eliminating some data with high superfluous Ar and those close to atmosphere, the authors get an isochron age (170±38) Ma (⁴⁰Ar/³⁶Ar Int.=299±10) and an inverse one (165±52) Ma (⁴⁰Ar/³⁶Ar Int.=303±23), respectively.It’s clear that Haigou deposit formed in Late Early Jurassic, combing with published isotopic geochronologies. Gold mineralization is closely related to subduction of the Kula plate under the ancient Asian plate in Mesozoic, particularly to the intensive convergence between the eastern North China plate and the eastern margin of the Xing’an-Mongolian orogenic belt, and to lithosphere thickening and thinning induced by this convergence.

Key words: fluid inclusion, single quartz grains, ⁴⁰Ar/³⁹Ar laser probe dating, isotopic geochronology, Haigou gold deposit