The Journal of the Geological Society of Japan
Online ISSN : 1349-9963
Print ISSN : 0016-7630
ISSN-L : 0016-7630
Volume 46 , Issue 545
Showing 1-4 articles out of 4 articles from the selected issue
  • Kiyosi TAKIMOTO
    1939 Volume 46 Issue 545 Pages 47-57
    Published: February 20, 1939
    Released: April 11, 2008
    JOURNALS FREE ACCESS
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  • Hisao OHTANI
    1939 Volume 46 Issue 545 Pages 58-68
    Published: February 20, 1939
    Released: April 11, 2008
    JOURNALS FREE ACCESS
    Wafangtien, the seat of the Fuhsien prefectural government, is located along the main line of the south Manchurian Railway, at a point some 10 km., north of the northern boundary of the Kuantung Leased Territory, and Kang-tzu-tien is a small village lying adjacently to the southwest of the town., The author investigated chiefly the Jurassic system developed in the Kang-tzu-tien district of some 1 sq., km., with special reference to the type of its structure, grade of disturbance and relation to other systems., The so-called Chiao-tou quartzite belonging to the Sinian system and developing in the western part of the district is paraunconformably overlain on its eastern side by the Lower and Middle Cambrian system which consists of quartzite or sandstone, slate and limestone., The Middle (?) Jurassic system under consideration which is composed of conglomerate, sandstone, sandy shale, coaly shale, and minor coal seams and measures some 200m., in thickness covers the eastern side of the Cambrian system clino-unconformably and is thrust by the Lower Proterozoic phyllites from the east with a thrust angle of 50°, Each one of these four systems is monoclinal to the east, and all of them except the Sinian system are covered by impure loess of the Quaternary or Diluvium., The general structure of the Jurassic system can be explained, in order of increasing accuracy, as (1) a monocline with easterly dip of about 50°, (2) a pitching synclinorium, (3) a pitching syncli., norium in the northern part plus pinching anticlinorium in the southern part or (4) a synclinorium-anticlinorium and cross-fold (or synclinal one)., For a more accurate description of the structure than is given by the fourth explanation, one must turn to such portions of the areas that have been investigated, and describe each of such portions separately., In the three areas where detailed investigation has been completed the structure is a combination of minor pitching anticlines and synclines with the axes of their folds generally pitching to the east., The axes of these minor folds are mostly separated for twenty or thirty meters from one another., The structure is not much disturbed by faults except the thrust mentioned above., It appears most proper to consider that the so-called Yenshan movement in the late Mesozoic period is responsible for the various contorted structures in different forms and scales which can be seen in the Jurassic system in the district.,
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  • Hidekata SHIBATA
    1939 Volume 46 Issue 545 Pages 69-83
    Published: February 20, 1939
    Released: April 11, 2008
    JOURNALS FREE ACCESS
    Aluminous minerals-corundum, andalusite, iron-cordierite, spinel, (hercynite), and tepaz-are found in protolithionite-topaz-banded strings with a width ranging from 1 cm to 15 cm in fine-grained granite at Yagenyama., Many parallel strings are found, each keeping a distance from 10 cm to 1 m., The granite is quite characteristic and contains a high content of quartz, some parts of which are of secondary origin in connection with greisenization., Partly the granite is altered to greisen near the contact with strings., In general the biotite is a later constituent than some of quartz., These biotite crystals showing greenish brown pleochroism often project into miarolitic cavities which are filled with feldspars., Besides, there is another type of biotite showing dark brown pleochroism, which although in a small quantity, crystallized under the normal granitic condition., Zoning arrangement of minerals in the strings is distinct., The marginal zone consists of acidic oligoclase (of the composition of Ab87An13), to some extent altered to sericite., The next zone consists of andalusite, corundum (sometimes iron-cordierite), and protolithionite., The central zone consists of topaz, protolithionite and sometimes zinnwaldite and graphite., A chemical analysis of the protolithionite is given in the table 4., Orthoclase-quartz-protolithionite-pockets are also found near the strings., The formation of these strings is due to a metasomatic origin, chiefly pneumatolytic, by mineralizers rich in fluorine or aluminium fluoride gas., The pockets are metasomatized pegmatite-druses., At first orthoclase was replaced, being more unstable than albite at the pneumatolytic stage, and corundum, andalusite, iron-cordierite, muscovite, and protolithionite were formed by addition of FeO concentrated in the residual magmatic liquid as hydroxyl-bearing silicate or hydrate., Later albite, andalusite, and cordierite were again replaced by topaz and protolithionite : spinel and corundum occur also as replacement products of this stage., Large sapphire crystals were produced by pneumatolysis independently., Wolframite-quartz veins, somewhat later derivatives, running in the elongated direction of the strings are related to the formation of the strings., Another same set of strings and veins running in a different direction are also found near Sengeyama.,
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  • Koiti SUZUKI
    1939 Volume 46 Issue 545 Pages 91-112
    Published: February 20, 1939
    Released: April 11, 2008
    JOURNALS FREE ACCESS
    The fossil gastropods dealt with in the present paper were collected by Dr., Tetsugoro WAKIMIZU from the loess at Tsingsing and the terrace deposit (the so-called "redeposited loess") at Shihkiachwang, both in Hopei Province., The material from Tsingsing comprises only three species as follows: Bradybaena (Manchurohelix) lavrushini (COCKERELL) (2 specimens) Cathaica fasciola (DRAPARNAUD) (4 specimens) Cathaica pulveratrix (von MARTENS) (2 specimens) Bradybaena lavrushini still lives in this district and the two species of Cathaica are most common snails in North China, both fossil and living., The state of preservation of the fossils is very excellent., The collection from Shihkiachwang contains three species of fresh-water gastropods and two of land snails, as listed below : Lymnaea (Galba) pervia von MARTENs (about 10 specimens) Lymnaea (Radix) plicatula BENSON (3 specimens) Anisus (Gyraulus) sp., (1 specimen) Opeas pyrgula SCHMACKER and BOETTGER (7 specimens) Metodontia yantaiensis (CROSSE and DEBEAUX) (6 specimens) All the species are now widely distributing throhghout North China., Most of the specimens before hand are not well preserved., The detailed synonymy, the dimensions the recent distribution and the fossil occurrence of each species are shown in the foregoing pages., Further, a tentative correlation table of the Cenozoic formations in North China and Manchuria is given in page 92, detailed discussion of which, however, will be reserved for another occasion., The results of the taxonomic studies are summarised as follows : 1) Limnaea (Gulnaria) shantungensis JONES and PRESTON (1904), Limnaea kingi PING and YEN (1933), Limnaea truncatula tenua PING and YEN (1933) and Galba laticallosiformis YEN (1937) are all synonyms of Lymnaea (Galba) pervia von MARTENS., The specimens of Lymnaea from South Ordos being referred to Galba truncatula (MULLER) by YEN (1937) are also identifiable with pervia, while Limnaea exigua PING and YEN (1933) described from Aksu evidently belongs to Lymnaea (Galba) truncatula (MULLER)., 2) Limnaeus chefouensis CLESSIN (1886), Limnaeus mollendorffianus CLESSIN (1886), Limnaea mars JONES and PRESTON (1904) and Limnaea whartoni JONES and PRESTON (1904) may be synonymous with Lymnaea (Radix) plicatula BENSON., Further, the specimens from Tai-hu being assigned to Limnaea clessini NEUMAYER by ANNANDALE (1918) undoubtedly belong to plicatula, and the shells referred to clessini by YEN in his recent paper (1937) on gastropods of North China seem more closely related to plicatula than to NEUMAYER's species., In the Ryukyu Islands, there is inhabiting a form of Lymnaea which can hardly be distinguished from plicatula., Many Japanese authors have referred it to Limnaea minor BENSON, but this identification does not seem reliable., In his description of minor, BENSON has given neither its illustration nor dimensions and has stated that it strongly resembles Lymnaea (Galba) truncatula (MULLER)., This species has never been reported from the Asiatic Continent, since it was first described from the Chusan Islands., 3) Opeas fragilis PING (1929), a fossil species from the Choukoutien formation, is nothing but a synonym of Opeas pyrgula SCHMACKER and BOETTGER., 4) A detailed description of Bradybaena lavrushini (COCKERELL) is given by Isao TAKI in a paper entitled "Mollusca of Jehol" (Report of the First Scientific Expedition to Manchoukuo, section 5, division 1, part 1, article 4) which will be published in the near future., A new subgenus, Manchurohelix, is proposed by him for this species basing upon the shell characters, and the composition of the genital system., 5) Cathaica transitans von MOLLENDORFF may be understood as an extremity of the individual variation, or at most as a subspecies, of Cathaica fasciola (DRAPARNAUD). [the rest omitted]
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