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Volume 39 (1985)
- Issue 6 Pages 393-
- Issue 5 Pages 301-
- Issue 4 Pages 243-
- Issue 3 Pages 175-
- Issue 2 Pages 105-
- Issue 1 Pages 1-
Volume 39, Issue 6
Displaying 1-8 of 8 articles from this issue
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Koichi HOYANAGI, Nozomi MITO, Masatoshi YOSHIOKA, Seigo MIYASAKA, Yasu ...Article type: Article
1985 Volume 39 Issue 6 Pages 393-405
Published: November 25, 1985
Released on J-STAGE: July 27, 2017
JOURNAL OPEN ACCESSThick Miocene sediments are distributed in the Ishikari-Teshio Belt along the western side of the Kitami mountain range in the north and the Hidaka mountain range in the south. In the southern part of this belt, the Miocene sequences are divided into the Furanui, Ukekoi, and Motokanbe Formations, in ascending order. The Furanui Formation (early Middle Miocene) consists mainly of greenish gray sandstones and mudstones The Ukekoi Formation (Middle Miocene) composed mainly of alternating beds of sandstone and mudstone and conglomerates, attains a maximum thickness of about 2,100 meters, which is correlated with the Kawabata Formation in the Ishikari district and the Kotanbetsu Formation in the Haboro district. The Motokanbe Formation (Late Miocene) consists mainly of hard shales and subordinate intercalated conglomerates. The Ukekoi Formation is subdivided lithologically into the U1, U2, and U3 members in ascending order. The U1 and U3 are composed mainly of alternating beds of sandstone and mudstone with Bouma sequences, and the U2 member consists of coarse clastic sediments with grading and imbrication structures developed well in the conglomerates. These facies are of turbidites and their related sediments. In the southern part of the studied area, these three members change laterally into the U4 member composed of alternating beds of sandstone and mudstone. The distribution pattern of these members can be assingned to the submarine fau environmental models of WALKER and MUTTI (1973) or WALKER (1978). The U2 member is of the upper fan channel-fill deposits in the northern part of this area and of mid-fan deposits in the central part. The U4 member in the southern part corresponds to the lower fan depoosits. The upper fan main channnel contains numerous smaller channels 10 meters or more deep and some 100 meters wide. These channels are filled with coarse clastic sediments transported from the north. On the basis of the above-mentioned discussion with the examination of the conglomerates, it is concluded that the Middle Miocene Ukekoi Formation is of submarine fan deposits transported far from the northern part of the Hidaka and Kamuikotan Belts, e. g. the Uenshiri Horst, while the Upper Miocene Motokanbe Formathionis of fan delta deposits derived from the eastern adjacent hinterland of the Hidaka Metamorphic Belt.View full abstractDownload PDF (2181K) -
Shusaku YOSHIKAWA, Katsuhiko FURUYAMAArticle type: Article
1985 Volume 39 Issue 6 Pages 406-415
Published: November 25, 1985
Released on J-STAGE: July 27, 2017
JOURNAL OPEN ACCESSThe Plio-Pleistocene Osaka and Kobiwako Groups which are widely distributed around Osaka Bay and Lake Biwa in central Kinki district, are composed of gravel, sand and clay with many intercalations of volcanic ash layers. The volcanic ash layers found in both groups are valuable markers for research in regional stratigraphy and also play the most important role for interbasinal correlation, because such layers represent essentially instants of geologic time and deposits over a wide area. In this paper, 22 glass separates from 16 prominent volcanic ashes in both groups were analyzed by nondistructive instrumental neutron activation technique, with the purpose of characterizing each of the ashes on the basis of trace element contents. The results obtained are the following: 1) Data for contents of trace elements (La, Sm, Th and Sc) in glass separates are presented in Table 2. Concentrations of La, Sm, Th and Sc, and La/Sm ratios are found to be characeristic and serve as good discriminants for the volcanic ash layers examined in this investigation. 2) Trace element data from this study shows that Mitsumatsu, Fukuda (Fugenji) and Azuki ashes are very similar to Kiryu II, Gokenjaya (Gamodo) and Risen ashes respectively. These facts support the correlation of the volcanic ash layers between the Osaka and Kobiwako Groups proposed by YOSHIKAWA (1983).View full abstractDownload PDF (992K) -
Tetsuyoshi YAMAZAKIArticle type: Article
1985 Volume 39 Issue 6 Pages 416-428
Published: November 25, 1985
Released on J-STAGE: July 27, 2017
JOURNAL OPEN ACCESSKuttara volcano overlies Tertiary sediments and in part, early to middle Quaternary andesitic volcanic rocks. The history of the volcano is divided into three stages: somma, caldera, and post caldera stages. Somma stage: A large stratovolcano, 6 km basal diameter and 1 km relative height was formed and made by olivine basaltic and pyroxene andestic lavas and pyroclastics. Caldera stage: Eruptive material of this stage is subdivided into three units which are in ascending order, the Rampoge pumiceous deposit, the Noboribetsu pumiceous deposit and the Noboribetsu base surge deposit. Rampoge pumiceous deposit (pyroxene andesitic) is composed mainly of four sheets of pumice flow deposits and three sheets of pumice fall deposits. Among them pumice fall deposits IIa and lib have a possibility of areal tephras. Noboribetsu pumiceous deposit (dacitic) is composed mainly of two sheets of welded pumice flow deposits, accompanied by pumice fall deposits. A fossil forest was found in the upper part of the deposit II (COLLABORATIVE RESEARCH GROUP for IBURI, 1983). Many fossil rootless fumaroles are developed in the upper unwelded part of the Noboribetsu pumiceous deposit I. 14C-age of the Noboribetsu pumiceous deposit II is 40,190 y. B. P. (Gak-10195). Karurusu clay bed was deposited in small lakes formed by the Noboribetsu pumiceous deposit. Noboribetsu base surge deposit overlies conformably the Noboribetsu pumiceous deposit I, and underwent fumarolic alteration as above mentioned. A caldera of Crater Lake type was formed immediately after the base surge deposit was formed. Post caldera stage: Last events of this area are the extrusion of Tachibanaike lava flow (pyroxene andesitic), and Hiyoriyama lava dome (dacitic), and the formation of explosion deposits of Oyunuma and Jigokudani. The total volume of Kuttara volcano exceeds 18 km3.View full abstractDownload PDF (2159K) -
Yukio ISOZAKI, Tetsuo MATSUDAArticle type: Article
1985 Volume 39 Issue 6 Pages 429-442c
Published: November 25, 1985
Released on J-STAGE: July 27, 2017
JOURNAL OPEN ACCESSFour new species of multi-segmented nassellarians, i.e. Laxtorum(?) jurassicum ISOZAKI & MATSUDA n. sp., L(?). hichisoense I. & M. n. sp., Hsuum hisuikyoense I. & M. n. sp. and H(?). matsuokai I. & M. n. sp., are described from early Jurassic bedded chert containing manganese micronodules at Kamiaso, Mino Belt, Central Japan. The assemblage including these four new species is referable to Hsuum sp. B Assemblage, reported from various localities throughout Japan (e.g. YAO et al., 1982). Through comparison with recently studied Early to Middle Jurassic radiolarians in North America and Turkey, the radiolarian assemblage reported herein is regarded to be most probably of late Early to early Middle Jurassic (Late Pliensbachian to Bajocian?) age.View full abstractDownload PDF (3274K) -
Kazue TAZAKI, W. S. FYFEArticle type: Article
1985 Volume 39 Issue 6 Pages 443-445
Published: November 25, 1985
Released on J-STAGE: July 27, 2017
JOURNAL OPEN ACCESSAlkali-feldspar in an alkaline rock shows evidence for the formation of iron rich primitive clay precursors in the earliest weathering stage. High-resolution TEM with EDAX, electron diffraction patterns and lattice images clearly show the decomposion of Alkali-feldspar and growth of primitive sheet structure mineral. The primitive clay precursors consist of Si and Fe with small amount of K and Al. These precursors with 14-20 A spacing show diffuse rings electron diffraction pattern due to low crystallinity and random orientation. The diameter of precursors is 150-200 A.View full abstractDownload PDF (3572K) -
Yasushi WATANABE, Keiji IWATAArticle type: Article
1985 Volume 39 Issue 6 Pages 446-452a
Published: November 25, 1985
Released on J-STAGE: July 27, 2017
JOURNAL OPEN ACCESSDownload PDF (875K) -
Norihisa INUZUKA, Katsumi TAKAYASU, Shigeru TANITOArticle type: Article
1985 Volume 39 Issue 6 Pages 453-458a
Published: November 25, 1985
Released on J-STAGE: July 27, 2017
JOURNAL OPEN ACCESSDownload PDF (1227K) -
Jun-ichi TAZAWAArticle type: Article
1985 Volume 39 Issue 6 Pages 459-462
Published: November 25, 1985
Released on J-STAGE: July 27, 2017
JOURNAL OPEN ACCESSDownload PDF (904K)
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