The Tamba sedimentary complex in the northern part of the Tamba Terrane, Southwest Japan, is tectonostratigraphically divided into six units; the Kowaki, Yajiro, Natasyo, Hisasaka, Tsurugaoka and Yuragawa Complexes, occurring from north to south in this succession. Greenstones occur as slabs within melange which composes these complexes, except for the Tsurugaoka and Yuragawa Complexes.
Major and trace element analyses including 11 new ones of 30 greenstones from the Yajiro, Natasyo and Hisasaka Complexes were plotted on various discrimination diagrams to constrain their parentage. The greenstones of both the Yajiro and the Natasyo Complexes include those having characteristics of MORB and those to be grouped in alkalic basalt and tholeiite of oceanic island, among which a few alkalic basalts of the Yajiro show a high Zr concentration. The greenstones of the Hisasaka Complex belong only to alkalic basalt of oceanic island, probably indicating a different tectonic regime of this complex from the others.

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The Sambagawa metamorphic terrain of the Kodama-Nagatoro area, Kanto mountains, is divided into three zones, on the basis of mineral parageneses and the graphitizing degrees of pelitic and psammitic schists: Zone I (chlorite zone), Zone II (garnet zone) and Zone III (biotite zone), in the order of ascending grade. Amphibole of basic schists is actinolite and rarely winchite in Zone I. However, the composition range of the mineral becomes wider in higher zones. It ranges from actinolite through actinolitic hornblende to hornblende in Zone lI and from actinolite through actinolitic hornblende and hornblende to barroisite in Zone III. The amount of tetrahedral Al in the amphiboles increases and its variation range widens with increasing grade. The host basic schists are classified into the following four types, according to the chemistry of their amphiboles, particularly to the amount of Al^IV: Type A, Al^IV in the amphiboles is 0.1-0.5, Type B, 0.1-0.9, Type C, 0.3-1.2, and Type D, 0.5 ?? more than 1.5. Type A schists occur mostly in Zone I, Type B in Zone 11 and Types C and D in Zone III. This is harmonious with the metamorphic zoning based on the petrology of pelitic and psammitic schists, because the maximum Al^IV indicates the maximum temperature, under which the host basic schists have been recrystallized. On the other hand, the maximun amount of Na in the M 4 sites increases slightly with ascending grade. The trend of compositional variation of the amphiboles suggests that the metamorphism took place principally under increasing temperature but with slightly increasing pressure.

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K-Ar dating was carried out on the Tertiary volcanic rocks from Okushiri Island in Japan Sea. We obtained K-Ar whole rock ages of 4.4±0.2, 20.4±0.5, 19.7±0.5 and 34.4±0.8 Ma for a basalt in the Kamuiyama Formation, an andesite in the Tsurikake Formation, an andesite in the Aonaegawa Formation and a basalt in the Matsue basalt Formation, respectively. The volcanic activity during Tertiary time in Okushiri Island are divided into main three stages, Oligocene (34-29 Ma), Early Miocene (23-20 Ma) and Pliocene (-4 Ma). The chemical compositions of representative 32 samples from the three stages were determined by XRF techniques, The Oligocene Matsue basalts (lower) are characterized by high contents of MgO, Ni and Cr whereas the upper Matsue basalts have high contents of HFS elements such as Ti, P, Zr and Nb, suggesting that the latter are different in chemical compositions from the typical island arc basalts. The Early Miocene volcanics composed mainly of calc-alkaline andesite and dacite, whose incompatible element contents are similar to those of the Quaternary volcanics from the back-arc side of the NE Japan arc. The Pliocene volcanics composed mainly of rock suites ranging from andesite to dacite of calc-alkaline series with subordinate amounts of basalt which have incompatible element contents comparable to those of the Pliocene alkali basalt from Kyuroku-shima Island, northeast Japan Sea. The NE Japan arc and the surrounding areas during the Oligocene to Early Miocene are characterized by occurrence of andesite and dacite of calc-alkaline series and tholeiitic and alkali basalts with high contents of HFS elements, and the calc-alkaline rocks were generally formed before basaltic volcanism took place.

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