All issues
Volume 58, Issue 1
Displaying 1-6 of 6 articles from this issue
- |<
- <
- 1
- >
- >|
-
Ikuko YAMADA, Nobuyuki BIZEN, Tomoyoshi KOSAKA, Chikako ISOMURAArticle type: Article
2004 Volume 58 Issue 1 Pages 1-16
Published: March 25, 2004
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSThe Uchimura Formation (late Early to early Middle Miocene) is exposed extensively in the southern part of the Uchimura area, which is belonging geologically to the Takai-Utsukushigahara Belt of the Northern Fossa Magna region. Sediments of the western part of the Uchimura area consist mostly of siliciclastic rocks and a part of alternated lavas and volcaniclastic rocks. Those are lithologically subdivided into eight members, Ayashizawa Volcaniclastics Member, Fujii Sandstone and Mudstone Member, Yamada Sandstone and Conglomerate Member, Asamatoge Sandstone and Mudstone Member, Ichinose Sandstone and Conglomerate Member, Misayamatoge Basalt Member, Hosoonotaki Volcanics Member and Kariyahara Sandstone and Mudstone Member. On the other hand, thick bedded lavas and volcaniclastic rocks are widely distributed in the central part of the Uchirnura area. These siliciclastic rocks and lavas and volcaniclastic rocks have an interfingering relationship in the boundary area of the western and central parts of the Uchimura area. Benthic foraminifers, occurred from the siliciclastic rocks, indicate that the Uchimura Formation has deposited in a middle bathyal zone (less than 700m depth). Data of gravel compositions and paleo-current directions obtained from siliciclastic rocks indicate that those of the Uchimura Formation might be derived from the southern to the western area of the Uchimura area. These provenances areas may correspond to the Mino Belt, Ryoke Belt and Nohi Rhyolites areas. The study area is tectonically divided into three areas. Each area may conform respectively to earsten of the Minochi Belt, the Takai-Utsukushigahara Belt and the Itoigawa-Sizuoka Tectonic Line.View full abstractDownload PDF (2480K) -
Atsuo KOTAKIArticle type: Article
2004 Volume 58 Issue 1 Pages 17-24
Published: March 25, 2004
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSThe Takurayama volcano is composed of lava plateaus and a scoria cone. The lavas are classified into three members, the Ogura, Kinuzuri and Takurayama lavas in ascending order. The scoria cone was formed after the eruption of the Takurayama lava. As the scoria is deeply weathered, the stratigraphic correlation using heavy minerals is difficult. The chemical composition of the preserved Fe-Ti oxides in scoria and lavas revealed that the scoria cone was genetically related with the Takurayama lava. The geological section along the Yakuno Tunnel is reinvestigated based on the petrographical study of core samples, and the basemental upheaval is not identified.View full abstractDownload PDF (1162K) -
Ryugasaki Collaborative Research GroupArticle type: Article
2004 Volume 58 Issue 1 Pages 25-36
Published: March 25, 2004
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSThe authors have investigated undescribed sedimentary facies of new outcrops in the southern Inashiki Upland. These facies are divided into 5 facies: Cross-stratified coarse-medium sand, Sandy silt, Clay, Microinterbeds of sand and silt and Bioturbated medium sand. Since Sandy silt contains "Kojimiso" pumice, these facies belong to the Kamiiwahashi Formation. Cross-stratified coarse-medium sand, Sandy silt and Clay are considered to be the channel/point bar, flood plain deposits respectively which were formed in the meandering river system during a low stand stage. Microinterbeds of sand and silt are considered to be the tidal flat deposits. Bioturbated medium sand includes abundant molluscan fossils (Mactra chinensis, Nitidotellina hokkaidoensis) and foraminifera fossils (Pseudononion japonicum, Elphidium kusiroense). These fossils indicate that Bioturbated medium sand was formed in the upper sublittoral zone (inner sublittoral zone) of an inner bay. Microinterbeds of sand and silt and Bioturbated medium sand were formed in the drowned valley system during a transgressive stage. Based on these results, the authors recognized that the sedimentary facies of the Kamiiwahashi Formation in the southern Inashiki Upland changed from meandering river system, through drowned valley system, to strandplain system.View full abstractDownload PDF (1540K) -
Toshio KUSUNOKI, Masaaki OHARA, Makoto MUSASHINOArticle type: Article
2004 Volume 58 Issue 1 Pages 37-54
Published: March 25, 2004
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSWe discovered the Permian chert block with alternating beds of chert and dolarenite, which are well exposed in the Shizukawa district, the Mt. Kisenyama area in the right bank of the Ujigawa river of the southern Tamba terrane. There are several intercalations of dolarenite layer in its lower part of the chert. In this continuous outcrops of bedded chert block, conodonts and radioralians were obtained from 52 chert samples. As a result of the investigation, it is clear that the Shizukawa section ranges in age from late Late Carboniferous to late Late Permian (Changhsingian). The C/P boundary in this Shizukawa section is presumed to be existed somewhere between the sample no.3 and the sample Se. This Sizukawa section is correlative with the Kasugabe section of chert and dolostone alternating beds from Southern Kameoka City.View full abstractDownload PDF (5848K) -
Hiroaki KOMUROArticle type: Article
2004 Volume 58 Issue 1 Pages 55-60
Published: March 25, 2004
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSDownload PDF (2266K) -
Yasumoto SUZUKIArticle type: Article
2004 Volume 58 Issue 1 Pages 61-64
Published: March 25, 2004
Released on J-STAGE: July 14, 2017
JOURNAL OPEN ACCESSDownload PDF (602K)
- |<
- <
- 1
- >
- >|