Kuroko Deposits of <scp>NE</scp> Japan: The Product of High‐Temperature, Shallow Felsic Volcanism in a Deepening Continental Rift

ABSTRACT The Hokuroku district of NE Japan hosts the type locality for Kuroko volcanic‐hosted massive sulphide (VHMS) deposits, which are the product of seafloor hydrothermal venting in a continental rift during the opening of the Sea of Japan in the Miocene. Here we reconstruct the thermal history of the magmas, and find that the shallow emplacement of felsic magmas (&lt; 100 MPa) reached a thermal maximum at the time of ore deposition (ca. 950°C). Post‐ore magmas stalled and crystallised at water‐saturated cotectic conditions at average temperatures of ca. 900°C. We propose an ore‐genetic model that combines the effects of increasing seawater depth (i.e., increasing hydrostatic pressure) on magma behaviour that led to increasing magmatic heat‐flux resulting in the episodic nature of ore deposition. Our results provide an interpretative framework that helps explain the localised occurrence of VHMS deposits that may be used as an indicator for mineral exploration in similar tectonic settings.