Earth Science (Chikyu Kagaku)

Quaternary Geology of the Upper Drinage Area of the Kiso River (I)

The Quaternary Research Group of the Kiso Valley

Article type: Article
1967 Volume 21 Issue 1 Pages 1-10a
Published: January 30, 1967
Released on J-STAGE: July 25, 2017

DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.1_1

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Burrows of Japanese Thalassinidea

Kazuo OHSHIMA

Article type: Article
1967 Volume 21 Issue 1 Pages 11-18b
Published: January 30, 1967
Released on J-STAGE: July 25, 2017

DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.1_11

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Burrows of the marine decapod are important structures in substrata of tidal flats along the Japanese coast. Most of the "sand-pipe" closely resemble to the burrows are commonly found in certain Tertiary and Quaternary shallow neritic sediments. The writer believes that observations on recent burrows of different animals may aid in solving the origin and paleoecological significances of " sand-pipes " in Tertiary and Quaternary strata. In this report, the writer deals with the shape of burrows and. phylogeny of Japanese Thalassinidea ; Axiidae, Thalassinidae, Laomediidae, Callianassidea and Upogebiidae. After each burrowing shrimp habits were observed on tidal flats, he made plaster moulds of each ones burrows. Following morphological descriptions of burrows based on these plaster moulds. 1. Thalassinidae and Laomediidae live in the same habitat and their food habits the same. Their shape of burrows are resemble with each other (P1. I, fig. 1, 2). 2. Upogebiidae (blue mud shrimps) and Callianassidae (ghost shrimps) live in the same habitat on the tidal zone, but their food habits and bodies style are very different from each other. The one feeds on detritus that it strains from tne current of water fanned through the burrow, the other feeds on organic detritus in substrata. The chelae of blue mud shrimps are equal in size but the ghost shrimps have a large chelate in right or left. In this case, the burrows of blue mud shrimps (P1. II, fig. 1, 2, 3, 4, 5) have thick muddy lining and small resistance to water current, the other ghost shrimps have thin film like wall and dendritic structures to substrate (P1. I, fig. 3, 4). Especially the globular parts of ghost shrimps burrows are most important feature, because such globular parts are necessary for their food habits. 3. The writer considered the phylogeny of Thalassionidea based on the habits, shape of burrows and geological occurrences. The phylogeny of Thalassionidea shown in figure 3.

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On geological structure of northern part of Itoigawa-Shizuoka tectonic line

A discussion on folding pattern and wrench fault

Naomoto KOMATSU

Article type: Article
1967 Volume 21 Issue 1 Pages 19-20
Published: January 30, 1967
Released on J-STAGE: July 25, 2017

DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.1_19

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Nitrogen analyses by micro-Kjeldahl method of the fossil shells yielded from the Johmon shell-mounds of the Kanto district, Japan

Kazue TAZAKI

Article type: Article
1967 Volume 21 Issue 1 Pages 21-24
Published: January 30, 1967
Released on J-STAGE: July 25, 2017

DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.1_21

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Nitrogen both in the recent and fossil shells were analysed by micro-Kjeldahl method, the latter being from the Johmon shell-mounds (2000-9000 years B.P.) in the Kanto district, Japan. It is difficult to separate the organic metrials from calcium carbonate without any loss especially in the fossil shells, so the nitrogen analysis of the shell should be carried out with much calcium carbonate, not to remove it. The writer is successful in quantitative nitrogen analysis of the organic materials with much calcium carbonate (Fig. 1). Both the fossil and recent samples analysed are Anadara broughtoni, A. subcrenata, Ostrea gigas, Corbicula iaponica, C. leana, Meretrix lusoria, Mya japonica and Neverita didyma, which are shown in Table 1 with places of occurrence, absolute ages, and weight percents of nitrogen in the shell. In so far as the fossil shells of the Johmon shellmounds are concerned, it is concluded that nitrogen content of the shell indicates rapid diminishing in 2000 years and slow decreasing since then (Fig. 2).

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Review of U-Th-Pb and Rb-Sr Earth Science (I)

Development of the Crust and the Mantle

Yoshiteru KONO

Article type: Article
1967 Volume 21 Issue 1 Pages 25-31
Published: January 30, 1967
Released on J-STAGE: July 25, 2017

DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.1_25

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Basic theories of isotope geology are critically discussed with a special attention to the development of the crust and the mantle. Available data of U-Th-Pb and Rb-Sr abundances in rocks are summarized (§ 2) and basic concepts of isochron, growth curve and development curve are discussed (§ 3). Present status in this research fields is reviewed reffering to the recently published two articles (§ 4).

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Precambrian of Africa (II)

Kanenori SUWA

Article type: Article
1967 Volume 21 Issue 1 Pages 32-44
Published: January 30, 1967
Released on J-STAGE: July 25, 2017

DOIhttps://doi.org/10.15080/agcjchikyukagaku.21.1_32

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