Tetori Group Research Articles

Lithostratigraphy of the Mesozoic Tetori Group in the upper reaches of the Kuzuryu River, central Japan

Lithostratigraphy of the Mesozoic Tetori Group in the upper reaches of the Kuzuryu River, central Japan

Triassic and Jurassic radiolarians in chert clasts of the Tetori Group in Tamodani area of Izumi Village, Fukui Prefecture, central Japan

Triassic and Jurassic radiolarians in chert clasts of the Tetori Group in Tamodani area of Izumi Village, Fukui Prefecture, central Japan

走向傾斜データによる荘川地域の手取層群の地質構造自動解析

走向傾斜データによる荘川地域の手取層群の地質構造自動解析

Geological and Palynological Studies on Quaternary Peat Deposits in Hirugano Tableland, Gifu Prefecture, Central Japan

There are some small tablelands at 800-1, 000 meters above the present sea level of the surround ing areas of Mt. Hakusan, Central Japan. Hirugano tableland which is one of them occupies at about 1, 000 meters of the northwestern part of Gifu Prefecture, and at the tableland some small moores are distributed sporadically. The present writers investigated on the peat deposits of these moores from the viewpoints of palaeoclimate and the cause of formation of the tableland.The conclusions of the study are summarized as follows:(1) The stratigraphy of Hirugano tableland is shown as the following table.Hirugano Member {Holocene Peat Deposits Middle-Late Pleistocene {Loam Layer Conglomerate LayerunconformityEarly Pleistocene Dainichidake-Washigatake Andesite GroupunconformityPliocene Shirotori Lake DepositsunconformityLate Cretaceous Nohi Rhyolite GroupunconformityLate Jurassic Tetori GroupThe lowermost part of the peat deposits was formed in about 7, 000 years before the present, 6, 680±130 years B. P. (GaK-3628), and the ratio of sedimentation of the peat deposits may be estimated as about 0.31mm/year.(2) The cause of formation of Hirugano tableland is concluded as follows:In the end of Early Pleistocene epoch the lava flows of andesite from Dainichidake and Washigatake damed up the south entrance of the basin which was formed by eroding the Late Jurassic Tetori Group, Late Cretaceous Nohi Rhyolite Group and Pliocene Shirotori Lake Deposits. For the reason this lake named Lake Hirugano was formed here. The conglomerate and pyroclastics belonging to the Hirugano Member were deposited in the lake throughout the Middle and Late Pleistocene epoch. Many moores which are distributed sporadically in Hirugano tableland show the last stage of Lake Hirugano filled up from the viewpoint of the histroy of lake. That is, the moores which we can see in Hirugano tableland are a relic of Lake Hirugano into our day.(3) The climatic change found in the peat deposits is summarized as follows.a: Warm stage: This stage is between about 7, 000 years and about 4, 000 years ago. This stage corresponds to the Postglacial climatic optimum age and the Atlantic and early part of the Subboreal in the pollen chronology of Europe.b: Cool stage: This stage is between about 4, 000 years and about 1300 years ago. An annual mean temperature of this stage is 0.5° to 1.0°C lower than that of the present time.c: Present climatic stage: This stage is the time after about A. D. 700. The present annual mean temperature of Hirugano tableland is 7.6°C.

On some new data concerning the Tetori Group in the middle of the Katakai River, Toyama Prefecture

In 1957 and 1960, the writer carried out geological survey of the middle of the Katakai River, Toyama Prefecture, with special attention to the Tetori group. As the result, the following new data are obtained : 1) The formations, narrowly exposed in the valley of the Katakai and BetsumatadaniRivers, consist of alternation of conglomerate, sandstone and shale, and are the northeastern extention of the Tetori group along the Joganji and Hayatsuki Rivers.2) The presence of the so-called reddish facies and the nature of the conglomerate facies suggest that the formations stratigraphically corresponds to the Shiroiwagawa alternation in the Joganji- gawa district. Therefore, it is believed that the formations belong to the Eo-Cretaceous rather to the upper Jurassic in age as was previously assingned.3) The fossil wood, Xenoxylon latiporosum (CRAMER) was newly descovered in these formations. The northern boundary of its distribution reaches the Betsumata valley.4) The basement rocks before the deposition of these formations show a very rugged relief.

The Tetori Group along the Asuwa River in Fukui Prefecture

The Tetori Group along the Asuwa River in Fukui Prefecture

An Interpretation of the Geotectonic Development of the Tetori Group in the Southern Part of the Kuzuryu River Valley, Fukui Prefrecture

An Interpretation of the Geotectonic Development of the Tetori Group in the Southern Part of the Kuzuryu River Valley, Fukui Prefrecture

Stratigraphy of the Tetori Group in the Southern Part of the Kuzuryu River, Fukui Prefecture

Stratigraphy of the Tetori Group in the Southern Part of the Kuzuryu River, Fukui Prefecture

Stratigraphy and Geological Structure of the Tetori Group in the Hakusan District (Part 2., Geological Structure)

Stratigraphy and Geological Structure of the Tetori Group in the Hakusan District (Part 2., Geological Structure)

Note on the Chemical Composition of a Sandstone from the Tetori Group

Note on the Chemical Composition of a Sandstone from the Tetori Group

The Source of the Pebbles of Quartz-porphyry in the Tetori Group

The Source of the Pebbles of Quartz-porphyry in the Tetori Group

Tetori Group in the Kitanomata-dake in the Northern Alps of Japan

In the western district of the Northern Alps of Japan, the Tetori groups are scattered, each in rather small area on the high mountains, such as Yakushi-dake, Kitanomata-dake, Kurobegoro-dake and others. In this paper the writer treats especially the group in the Kitanomata-dake area. The area is covered mainly by the Oritate-toge conglomerate, which is the basal one of the Itoshiro subgroup occupying the middle division of the Tetori group and is composed of the rounded pebbles of granite, gneiss, quartz-porphyry, cherty rocks, sandstone, hornfels and so on. The conglomerate along the upper drainage of the Kitanomata River, forming a monoclinic structure, is a southeastern part of the large basin structure situating in the southern district of Toyama Prefecture. On the eastern margin of this basin, the conglomerate unconformably overlies the basement of the Shimonomoto-type granitic rocks which intruded in late Palaeozoic, whereas on the southeastern margin is normal fault contact with the plutonic rocks of the same type. In the valley of the Kitanomata River the fossil plants are found, such as Cladophlbis exiliformis (Geyler), Onychiopsis elongata (Geyler), Podozarnites lanceolatus (Lindley and Hutton) and Xenoxylon latiporosum (Gramen), the discovery of the last of which is significant of its extensive distribution on the Tetori group.

Stratigraphy and Geological Structure of the Tetori Group in the Hakusan District (Part 1.Stratigraphy)

Stratigraphy and Geological Structure of the Tetori Group in the Hakusan District (Part 1.Stratigraphy)

New Locality of the Tetori Group and the Tetori Flora in the Midstream Region of the Asuwa River, Fukui Prefecture, Central Japan

New Locality of the Tetori Group and the Tetori Flora in the Midstream Region of the Asuwa River, Fukui Prefecture, Central Japan

Stratigraphy and Geological Structure of the Tetori Group in the Hida Mountainland

Stratigraphy and Geological Structure of the Tetori Group in the Hida Mountainland

The Tetori Group in the Oyama Area, Itoshiro Village, Fukui Prefecture

The Tetori Group in the Oyama Area, Itoshiro Village, Fukui Prefecture

Note on the Sedimentary Provinces in the Tetori Group

Note on the Sedimentary Provinces in the Tetori Group

Stratigraphy and Geological Structure of the Tetori Group along the Uchinami and Itoshiro Rivers, Fukui Prefecture

Stratigraphy and Geological Structure of the Tetori Group along the Uchinami and Itoshiro Rivers, Fukui Prefecture

The Erosion Surfaces on the Haku-san Mountain Ranges and its Adjacent Area

As the result of the writer's survey on the erosion surfaces in the Haku-san mountain ranges and its adjacent areas, 19481954, the following main facts are known : 1) The Bessan erosion surface having about 2200 m. to 2300 m. in height lies near the peak of Bessen (2399.4 m. high) which is composed mainly of coarse grained sandstone and conglomeratic sandstone of the Tetori group of Mesozoic. Bessan, which lies to the south of the Haku-san volcanoes, and protrudes about 100 m. from the Bessan erosion surface, is seemed to be a monadnock on this surface.2) The basement of the Haku-san volcanoes shows from 2200 m. to 2300 m. in height. Therefore it is thought that the surface on this basement is the northern extention of the Bessan erosion surface.3) The Shira-kawa erosion surfaces having 1700 m. to 1800 m. in height are distinctly observed at Sarugababa-yama, Gozen-dake, Hideri-dake and other places, and these surface are about 300500 m. lower than those of Bessan district.4) The flat plane west of Gankyoji mountain in the Koike area was formerly considered as an erosion surface by predecessors but it is now regarded as a deposited plane due to the volcanic activities of the Gankyoji mountain.5) The Bessan and Shira-kawa erosion surfaces have been formed during from post-Miocene to the pre-Haku-san volcanic activities in Quaternary, and the former erosion surface seems to be more or less older than the latter in age.

Stratigraphy and Geological Structure of the Tetori Group in the Southern District of Toyama Prefecture

Stratigraphy and Geological Structure of the Tetori Group in the Southern District of Toyama Prefecture