『Abstract
　The northeast (NE) Honshu arc was formed by three major volcano-tectonic events resulting from Late Cenozoic orogenic movement: continental margin volcanism (before 21 Ma), seafloor basaltic lava flows and subsequent bimodal volcanism accompanied by back-arc rifting (21 to 14 Ma), and felsic volcanism related to island arc uplift (12 to 2 Ma). Eight petrotectonic domains, parallel to the NE Honshu arc, were formed as a result of the eastward migration of volcanic activity with time. Major Kuroko volcanogenic massive sulfide (VMS) deposits are located within the eastern marginal rift zone (Kuroko rift) that formed in the final period of back-arc rifting (16 to 14 Ma). Volcanic activity in the NE Honshu arc is divided into six volcanic stages. The eruption volumes of volcanic rocks have gradually decreased from 4,600 km³ (per 1 my for a 200-km-long section along the arc) of basaltic lava flows in the back-arc spreading stage to 1,000-2,000 km³ of bimodal hyaloclastites in the back-arc rift stage, and about 200 km³ of felsic pumice eruptions in the island arc stage. The Kuroko VMS deposits were formed at the time of abrupt decrease in the eruption volume and change in the mode of occurrence of the volcanic rocks during the final period of back-arc rifting. In the area of the Kuroko rift, felsic volcanism changed from aphyric or weakly plagioclase phyric (before 14 Ma), to quartz and plagioclase phyric with minor clinopyroxene (12 to 8 Ma), to hornblende phyric (after 8 Ma), and hornblende and biotite phyric (after 4 Ma). The Kuroko VMS deposits are closely related to the aphyric rhyolitic activity before 14 Ma. The rhyolite was generated at a relatively high temperature from a highly differentiated part of felsic magma seated at a relatively great depth and contains higher Nb, Ce, and Y contents than the post-Kuroko felsic volcanism.The Kuroko VMS deposits were formed within a specific tectonic setting, at a specific period, and associated with a particular volcanism of the arc evolution process. Therefore, detailed study of the evolutional process from rift opening to island arc tectonics is very important for the exploration of Kuroko-type VMS deposits.

keywords: Kuroko; Volcanogenic massive sulfide; VMS; Felsic volcanism; Island arc; Back-arc rifting; Japan』

Introduction
General geology of the Late Cenozoic NE Honshu arc
Volcanic geology with special emphasis on the volcanic history of the Late Cenozoic NE Honshu arc
　Volcanic stages 1 and 2: continental margin volcanism
　Volcanic stage 3: early back-arc spreading volcanism
　Volcanic stage 4: late back-arc rift volcanism
　Volcanic stages 5 and 6: island arc stage volcanism
Detailed geology
　Volume change during Late Cenozoic volcanism
　Volcanic stages 1 and 2: continental margin volcanism
　Volcanic stage 3: early back-arc spreading volcanism
　Volcanic stage 4: late back-arc rift volcanism
　Volcanic stages 5 and 6: island arc volcanism
Felsic volcanism around the Kuroko VMS deposits
　Geologic framework of Kuroko horizon
　Petrography of the felsic volcanic rocks related to the Kuroko VMS deposits
　Petrochemistry of felsic volcanic rocks related to the Kuroko VMS deposits
Discussion
　Late Cenozoic tectonic and magmatic evolution in the NE Honshu arc
　The restricted spatial distribution of the Kuroko VMS deposits
　Kuroko VMS deposits as the last submarine volcanic products of back-arc magmatism
　Implication of petrographic differences between pre- and post-Kuroko rhyolites
　Progressive change in phenocryst assemblage of felsic magma
Conclusions
Acknowledgment
References