北海道北東部における浅熱水性鉱化作用の時空変遷

抄録

Many epithermal Au-Ag, Cu-Pb-Zn and Hg deposits are distributed in the Northeast Hokkaido Metallogenic Province (NHMP). Thirteen K-Ar ages for hydrothermally altered rocks and quartz-adularia veins from Au-Ag deposits and Cu-Pb-Zn deposits, were determined to estimate thier mineralization ages. The newly-obtained age data and reported ones show that mineralization ages vary from approximately 14.4 Ma to 0.3 Ma, and tend to young southward in the NHMP. Based on the distribution of epithermal deposits and mineralization ages, this metallogenic province is divided into Ohmu-Monbetsu (14.4-11.2 Ma), Ikutahara-Rubeshibe (8.1-2.9 Ma) and Kamishihoro-Akan (3.8-0.3 Ma) areas, lying in an E-W trending parrallel arrangment along to Kuril Arc. Temporal and spatial evolution of mineralization is in accordance with the feature of terrestrial Miocene-Pleistocene volcanism which was initially widespread, but gradually became spatially restrict-ed towards the south in the NHMP.