Recent advances in the study of Precambrian geosciences in several crustal fragments of East Gondwana allow us to constrain the assembly of East Gondwana during the Precambrian and its tectonic history up to the time of the great Gondwana formation. Assembly of East Gondwana surrounding Antarctica during the Precambrian has been well constrained through extensive studies. Juxtapositions of Antarctica with southeast Africa, with India and Sri Lanka, and with Australia are all based on reliable data of various geoscientific aspects, and each juxtaposition does not conflict each other rendering further support for the reliability of the assembled Precambrian East Gondwana. Within the assembled East Gondwana, a ca 1100 Ma mobile belt surrounding East Antarctica (the Circum East Antarctic Mobile Belt: CEAMB) is pointed out to have taken a principal role for the birth of East Gondwana. A tectonic interpretation of East Gondwana during the Mesoproterozoic, covering the dextral transcompressional tectonics identified in the eastern part and orthogonal compressional regime in the central to western parts of CEAMB is considered to be an important topics in the near-future. The Pan-African events (ca 500-700 Ma) in East Gondwana is pointed out to be principally the rejuvenation of the once formed crust through the Circum East Antarctic Orogeny, although another possibility that East Gondwana assembled during the Pan-African orogeny remained to be examined. Recent findings of Neoproterozoic rocks from some parts of East Antarctica are noticed to be a key role for the further clarification of the signature of the Pan-African tectonics in East Gondwana.

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Major and trace elements analyses of Upper Permian Toyoma shales and Mesozoic shales have been carried out to clarify the provenance of the Southern Kitakami Terrane. The Toyoma shales are characterized by depletion in K₂O, Rb, Cs, Th and light REE (rare earth elements) compared with PAAS. They also show similar value or slight enrichment in Fe₂O₃, MgO, V, Sc and the middle and heavy REE. On Cr/Zr-Y/Ni and Co/Y-Ti/Zr diagrams, the Toyoma and Mesozoic shales plot in a field suggestive of an intermediate plutonic rock source. The shales of the Toyoma Formation show higher CIA (Chemical Index of Alteration) values (=68〜78) than Triassic shales (CIA=59〜67), indicating relatively weathered rocks in the source area. The Jurassic shales again show similar CIA values to those of the Toyoma shales. Permian shales of the Southern Kitakami plot in an intermediate field, between those of the Maizuru Terrane of the Inner Zone, and the Kurosegawa Terrane of the Outer Zone of Southwest Japan on the Ti/Zr-Co/Y diagram. On Th-Hf-Co and La-Th-Sc diagrams, JSl-1 (Toyoma shale) also plots between the Maizuru and Kurosegawa shales. This suggests that the Southern Kitakami Terrane had a provenance intermediate between that of the evolved Maizuru Terrane and the less evolved Kurosegawa Terrane. This intermediate nature of the source rocks of the Southern Kitakami was retained with little variation from Late Permian to Jurassic time.

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The garnet-biotite-muscovite granite in the Iide Mountains occurs as numerous small concordant bodies in sedimentary rocks of the Ashio Belt. It is medium to fine grained, leucocratic and composed mainly of quartz, plagioclase, k-feldspar, biotite, muscovite and garnet. Bulk chemical compositions of the garnet-biotite-muscovite granite are peraluminous whose Al₂O₃/(CaO+Na₂O+K₂O) (molecular ratio) are 1.05-1.19. The garnet is rich in spessartine molecule (sps.26.69-46.12%), whose rim is richer in Mn and poorer in Mg than the core indicating a reverse zoning. Mn/(Mg+Fe+Mn+Ca) (atomic ratio) of garnet and MnO/(MgO+FeOt+MnO+CaO) (molecular ratio) of whole rock are mutually related. Mg/(Mg+Fe+Mn) (atomic ratio) of biotite and MgO/(MgO+FeOt+MnO) (molecular ratio) of whole rock, anorthite content of plagioclase and CaO/(CaO+Na₂O+K₂O) (weight percent ratio) of whole rock are also correlated. The garnet crystallized from a Mn-rich peraluminous magma, because it is spessartine rich, reversely zoned and its Mn content is correlated with that of the whole rock. The biotite and plagioclase also crystallized from the peraluminous magma, as their compositions are also correlated with whole rock chemistry. The garnet bearing tonalite in the Hidaka Metamorphic Belt is poor in Or content and rich in An content and separated from the garnet-biotite-muscovite granite in the Iide Mountains by a cotectic line on the normative An-Ab-Or diagram. Therefore, it is difficult to get the garnet-biotite-muscovite granite magma of the Iide Mountains from the garnet bearing tonalite magma of the Hidaka Metamorphic Belt, which is representative of anatectic melt from pelitic granulite of high T/P type metamorphic belt. The garnet of the garnet bearing tonalite in the Hidaka Metamorphic Belt is poorer in spessartine molecule (sps.2.4-6.1%) than the garnet of the garnet-biotite-muscovite granite in the Iide Mountains. This contrast is probably caused by the difference of temperature, pressure and composition of the magma at the stage of garnet crystallization.

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The Middle Pleistocene Onoko volcano is situated at the southernmost part of the Northeast Japan volcanic arc. The volcanic history of the Onoko volcano can be divided into the following three stages. Stage 1: Junigatake stratovolcano, a conical-shape volcano with total volume of 13km³ and 1800m high above sea level, was formed. It is composed of lava flows and volcaniclastic rocks of basaltic and andesitic composition. The crater was probably located at about 300m to the west of the summit of Mt. Onoko. Junigatake-minami explosion crater was formed at the western flank of this stratovolcano, and also the Nakanotake mass and the andesitic radial dikes intruded in this stage. Stage 2: Collapse of the Junigatake stratovolcano took place, and a relatively small-scale caldera (about 2km in diameter) was formed at the summit of the stratovolcano, and small U-shaped valleys (about 100m deep and 1km wide) were also formed both at the southeastern and the northeastern franks of the volcano. In relation to this collapse, a debris avalanche occurred and the deposits are distributed on the foot of Onoko volcano. Stage 3: Voluminous andesitic lava flows (Miyazawa lava and Onokoyama-minami lava) extruded and the Onokoyama mass intruded in the final stage. Andesitic magmas most probably rose through E-W trending fault. This is suggested by the difference of the height of the Miocene basement rocks beneath the volcano.

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Many fossils of the Donaciinae were found from the Lower Pleistocene Bushi Formation of the Kazusa Group at Iruma River, Iruma City, Saitama Prefecture, Japan. Most Donaciinae fossils were compared with genus Plateumaris, whose pronotum is rather remarkably characteristed by its microsculpture. Therefore, I describe it as a new and extinct species, Plateumaris dorsata, sp. nov. The fossil specimens of P. dorsata have many common characters with P. weisei and P. germari, members of the P. pusilla species group.

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