Southern Kitakami Massif Research Articles

Sedimentary history with biotic reaction in the Middle Permian shelly sequence of the Southern Kitakami Massif, Japan

AbstractThe transition of sedimentary environments and their organism‐related responses is exemplified in the active margin setting of the Middle Permian in the Southern Kitakami Massif. The transition in the sedimentary environment began with a shallowing‐upward sequence at an upper slope to an outer shelf depositional setting that was associated with a delta system which transported abundant botanic remains in the Hoso‐o Formation. By contrast, the sediments of the overlying Kamiyasse Formation, the base of which is roughly equivalent to the lowermost Capitanian, were deposited at a lower shoreface to the outer shelf setting, which originated from complex depositional sources, including beach, near shore reef mounds and a nearby independent area of shallow and hard substratum with a considerable difference of depth. This unique depositional setting resulted in the seemingly ‘mixed’ fauna associated with this formation. The depositional environment of the overlying Kurosawa Formation is similar to that of the Hoso‐o Formation, but with far fewer monotonous biotic remains. A comparison of lithological characteristics and fossil remains with those of neighboring regions suggests that the independent mounds were generated as if the talus formed elsewhere so as to provide a large amount of skeletal elements to a deeper basin in the earliest Capitanian. Accordingly, the complex sedimentary setting observed in the Kamiyasse Formation occurs widely throughout the South Kitakami Massif, making possible the ‘mixed’ and seemingly diverse fauna from a mixture of multiple allochthonous origins.

1021 Latest Permian ammonoid Paratirolites from the Ofunato district, Southern Kitakami Massif, Northeast Japan

1021 Latest Permian ammonoid Paratirolites from the Ofunato district, Southern Kitakami Massif, Northeast Japan

PERMIAN AMMONOIDS PROSTACHEOCERS AND PERRINITES FROM THE SOUTHERN KITAKAMI MASSIF, NORTHEAST JAPAN

Permian shallow marine strata are widely distributed in the Southern Kitakami Massif, Northeast Japan. They yield many marine fossils and have been well studied both stratigraphically and biostratigraphically. However, the geological age of the upper part of the Permian in the Tassobe district, located in the northern part of the Southern Kitakami Massif (Fig. 1), is still an unsettled question. The Permian is divided into the lower Tassobe and upper Sotokawame Formations (Okuyama, 1980; Yoshida et al., 1992). Early Permian (Sakmarian–Artinskian) fusulinoideans have been known from the middle to lower-upper part of the Tassobe Formation (Hirokawa and Yoshida, 1956; Saito, 1968; Yoshida et al., 1992), whereas no age-diagnostic fossils have been found from the overlying Sotokawame Formation. In the course of the geologic survey of the Permian, we collected two ammonoid fossils from the lower part of the Sotokawame Formation, which can provide us a basis for stratigraphic correlation. This paper describes these ammonoids and discusses their stratigraphic and biogeographic significance. Figure 1 —Location map of the study area The Carboniferous Okawame and Permian Tassobe and Sotokawame formations occupy the Tassobe district (Fig. 2). The Tassobe Formation, unconformably covering the Lower-Middle Carboniferous Okawame Formation, is divided into three lithologic units: the lower, middle, and upper parts. The lower part is 300– 350 m thick and consists of sandstone and mudstone, with minor amounts of conglomerate (Fig. 3). The middle part, 450–550 m in thickness, is composed mostly of limestone with intercalated mudstone. The upper part consists mainly of mudstone associated with lenticular limestones and its total thickness reaches 450 m. From the limestone of the middle part, fusulinoidean fossils such as Robustoschwagerina shellwieni (Hanzawa, 1938); Pseudofusulina kraffti (Shellwien and Dyhrenfurth, 1909); P. paramotohashii Morikawa, 1960; Charaloschwagerina vulgaris (Shellwien and Dyhrenfurth, 1909); and Parafusulina chihsiaensis (Lee, 1931 …

Middle Permian ammonoids from the Kamiyasse-Imo district in the Southern Kitakami Massif, Northeast Japan

ABSTRACT Middle Permian ammonoid faunas are recognized from the Hosoo and Kamiyasse Formations in the Kamiyasse-Imo district, north of Kesennuma, Southern Kitakami Massif, Northeast Japan. The faunas comprise the following genera: Parastacheoceras, Demarezites, Demarezites?, Waagenoceras, Timorites, Tauroceras?, Cardiella, Adrianites, Agathiceras, Agathiceras?, Paraceltites and Cibolites. Parastacheoceras bidentatus gen. and sp. nov. is newly proposed. The genera Demarezites, Tauroceras, Cardiella and Adrianites are described for first time from Japan. Based on these ammonoids, the middle part of the Hosoo Formation, upper part of the Hosoo Formation to the lower middle part of the Kamiyasse Formation, and upper middle part of the Kamiyasse Formation are correlatable with the Middle Permian Roadian, Wordian and Capitanian, respectively. The discovery of genera Demarezites and Cardiella strongly supports the previous hypothesis that the South Kitakami Paleoland was located in the equatorial province during...

Stratigraphic range of the genus Monodiexodina (Permian Fusulinoidea): additional data from the Southern Kitakami Massif, Northeast Japan

The fusulinoidean species Monodiexodina matsubaishi (Fujimoto), thought formerly to be an index fossil of the lower Middle Permian M. matsubaishi Zone, was recovered from the Lepidolina multiseptata Zone in the Kamiyasse-Imo district, Southern Kitakami Massif, Northeast Japan. This indicates that the stratigraphic range of the genus Monodiexodina in the Southern Kitakami Massif should be extended upward into the Capitanian Stage of the upper Middle Permian, as in the southern Primorye.

Some additional Wuchiapingian (Late Permian) ammonoids from the Southern Kitakami Massif, Northeast Japan.

Some additional Wuchiapingian (Late Permian) ammonoids from the Southern Kitakami Massif, Northeast Japan.

Reply to the Kobayashi's comments on "Limestone-dominated Middle Permian in the northern part of the Maiya district, Southern Kitakami Massif, Northeast Japan"

Reply to the Kobayashi's comments on "Limestone-dominated Middle Permian in the northern part of the Maiya district, Southern Kitakami Massif, Northeast Japan"

北部北上山地，田野畑深成複合岩体接触帯の変成作用 白亜紀深成岩類マグマ溜りの深度の解明に向けて

The Tanohata plutonic complex, northern Kitakami Massif, Northeast Japan, is an early Cretaceous zoned pluton mainly composed of hornblende-biotite granodiorite. The complex is in a wall contact relation in its western margin and in a roof contact relation in the northern part of the complex, with surrounding sedimentary rocks of the Jurassic accretionary complex. The width of thermal aureole is about 5-7 km in the “western marginal area”. Sedimentary rocks in the “northern roof pendant area”, with an extension about 10×8 km, are thoroughly metamorphosed extensively. The aureole is divided into four progressive mineral zones, namely, the biotite, cordierite, cordierite-K-feldspar and garnet-cordierite zones, based on the paragenetic changes of pelitic rocks in the western marginal area. In the northern roof pendant area, only the cordierite-K-feldspar and garnet-cordierite zones are recognized, and the width of each zone is several times larger than that in the western marginal area. The distinct development of high-temperature zones in the northern roof pendant area indicates a selective upward heat transfer during cooling of a granodioritic magma chamber of the Tanohata complex. Conditions of metamorphism are estimated from the biotite-muscovite-cordierite-sillimanite-K-feldspar equilibrium at the sillimanite isograd, the Fe-cordierite-almandine-sillimanite equilibrium in the garnet-cordierite zone and the garnet-biotite geothermometry. The estimated temperatures are at about 560°C at the sillimanite isograd, and in a range of 650-750°C in the garnet-cordierite zone, at pressures of 2-3 kbar. The maximum temperatures of the Tanohata aureole are similar to those of the highest temperature zone of the Tono contact metamorphic aureole in the southern Kitakami Massif. The result implies that the thermal properties of magma and the surrounding wall rocks are quite similar between the Tanohata and Tono plutons. The estimated pressures of contact metamorphism are also quite similar between Tanohata and Tono aureoles, indicating that these two granodioritic bodies both emplaced and solidified in a deep part of upper crust (7-11 km) during early Cretaceous magmatism in the Kitakami Massif.

南部北上山地水沼地域の大和田層より産出した中期ジュラ紀アンモノイドとその意義

南部北上山地水沼地域の大和田層より産出した中期ジュラ紀アンモノイドとその意義

Early Carboniferous ammonoid Irinoceras from the Onimaru Formation in the Southern Kitakami Massif, Northeast Japan.

Early Carboniferous ammonoid Irinoceras from the Onimaru Formation in the Southern Kitakami Massif, Northeast Japan.

994 Cephalopod fauna of the Nakadaira Formation (Lower Permian) in the Southern Kitakami Massif, Northeast Japan

994 Cephalopod fauna of the Nakadaira Formation (Lower Permian) in the Southern Kitakami Massif, Northeast Japan

南部北上山地大沢層（下部三畳系）よりヒボドゥス属板さい類の発見

南部北上山地大沢層（下部三畳系）よりヒボドゥス属板さい類の発見

Late Devonian and Early Carboniferous ammonoids from the Tobigamori Formation in the Southern Kitakami Massif, Northeast Japan and their stratigraphic significance

Late Devonian and Early Carboniferous ammonoids from the Tobigamori Formation in the Southern Kitakami Massif, Northeast Japan and their stratigraphic significance

南部北上山地のペルム紀アンモナイト類 その層位的分布とペルム系の分帯

南部北上山地のペルム紀アンモナイト類 その層位的分布とペルム系の分帯

Early Carboniferous Plants from the Hikoroichi Formation, Southern Kitakami Massif, Northeast Japan (Preliminary report)

Early Carboniferous Plants from the Hikoroichi Formation, Southern Kitakami Massif, Northeast Japan (Preliminary report)

Discovery of Rotodiscoceras from the Upper Permian of southern Kitakami Massif and its significance

Discovery of Rotodiscoceras from the Upper Permian of southern Kitakami Massif and its significance

Geological and Structural Studies of the Area along the Hizume-Kesennuma Tectonic Line, in Southern Kitakami Massif

Geological and Structural Studies of the Area along the Hizume-Kesennuma Tectonic Line, in Southern Kitakami Massif

Stratigraphy of the Permian System in the Area of Toyoma Town, Southern Kitakami Massif, Japan

Stratigraphy of the Permian System in the Area of Toyoma Town, Southern Kitakami Massif, Japan

Permian-Triassic Boundary in the Japanese Islands

In the southern part of the Kitakami Mountainland, North-east Japan, the Permian-Triassic boundary is often well exposed, where the Upper Permian Toyoma Slate and the Lower Triassic basal member of the Inai Group are intimately associated. There, T. Kobayashi once inferred the Tate epeirogeny and later Y. Onuki the Otani orogeny at the Permian-Triassic interval. N. Kanbe who dealt with the gradual transition between the topmost Permian and basal Triassic limestones in Kyûusyû, stated, referring to the Permian-Triassic boundary in the Kitakami Mountainland, “the crustal movement occurred at the Permian-Triassic transition was no more than gentle undulation, although erosion took place at emerged part”.On the other hand, F. Ueda. after his many years' field studies. declared in his paper. “The geological structure of the Permian and Triassic in the Toyoma and Maiya district, southern Kitakami Massif, North-east Japan” (in Japanese), 1963, that he could trace a fairly large overthrust sheet of Permian formations in the Toyoma-Maiya district, Tome-gun, Miyagi Prefecture, along the east side of the Kitakami-gawa.The Permian system of the district, approximately trending N-S, consists of, in descending orderToyoma Slate, lacking fusulinids, Yamazaki Conglomerate (Usuginu Conglomerate), Yabeina zone, Tenzinnoki formation, Parafusulina matsubaishi zone (corresponding to the Neoschwagerina-Verbeekina zone of the other regions in Japan), Nisikori formation, upper part, Parafusulina zone, lower part, Pseudoschwagerina zone.His geological and tectonic maps (Pls. I, VII) show the overthrust sheet built essentially of Upper (eastern) layer of the Toyoma Slate, Middle (intermediate) layer of the Yamazaki Conglomerate, Lower (western) layer of the Yamazaki Conglomerate and Tenzinnoki formation closely folded together.The upper layer, the Toyoma Slate, is unconformably overlain by the Hineusi formation thought to be contemporaneous with the Lower Triassic Hiraiso formation of the Inai Group ; the boundary of the two formations is said to be strongly undulated, indicating an intense erosion interval.The boundaries on the maps, between the overthrust sheet and its superjacent Hineusi formation and subjacent foundation structure, as well as these between its three component tectonic layers are parallel to each other in broad sense, though variously undulated in themselves.The foundation of the overthrust sheet is built of the Nisikori, Tenzinnoki, and Yamazaki formations ; these formations are closely folded and in general overturned to east, but partly to the opposite direction, perhaps under the influence of the westward shift of the overthrust sheet.Now assuming Ueda's conception about his overthrust sheet as well established, there arises another question regarding to the geological age of this tectonic event. Ueda dated it at the Permian-Triassic interval, based on the fact that whereas the Permian system of the overthrust sheet and its foundation is extremely complicate in structure, the Triassic Inai Group is tranquil in its general behaviour. Furthermore, the tectonic lines separating six transverse segments of the overthrust sheet from each other do not extend into the overlying Triassic deposits, and there is also no trace of any significant relative shifting nor shearing between the Toyoma Slate and the Hineusi formation.There are, however, certain geological features incongruent with Ueda's view, mentioned below.

Paleozoic Formations in Shimoarisu Village, Southern Kitakami Massif, Northeast Honshu, Japan

Paleozoic Formations in Shimoarisu Village, Southern Kitakami Massif, Northeast Honshu, Japan