All issues
Volume 55, Issue 640
Displaying 1-3 of 3 articles from this issue
- |<
- <
- 1
- >
- >|
-
Kiyosi ASANO1949 Volume 55 Issue 640 Pages 1-4
Published: February 20, 1949
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSThe presence of living Cyclammina from the seas bordering Japan was recorded as early as 1884 by BRADY and later again by CUSHMAN in 1910., More recently, the Soyo-maru of the Imperial Fisheries Experimental Station in Tokyo, during oceanographical observations and dredge operations on the continental shelf sea of Japan, made a large collection of Cyclammina cancellata BRADY by which our knowledge has increased., In regard to the fossils of the genus, Y., OTUKA (1932) recorded Cyclammina trullisata (BRADY) from a Pliocene formation in the South of Sanuki-machi (Chiba-ken); this may be the only record from the Pliocene., According to N., IKEBE (1940), Cyclammina is very abundant in the Niigata oil-fields, especially in the Shiiya formation (sandstone, and an alternation of sandstone and shale, and underlying Kubiki formation (predominated by black shale), for which reason the name of Cyclammina-Zone was applied by him., Research on Cyclammina in the Institute of Geology add Palaeontology, Tohoku University, has resulted in the identification of six forms as shown in Table 1., These materials, except for one from the Miocene of the Joban coal-field, are all from the Niigata oil-fields and are believed to belong to the Cyclammina zone of N., IKEBE., Most of these six forms which represent new species are here treated as A, B, C, D, E, and forms., Their localities and distribution wuthin the formations are given in Table 2, and their characters are briefly mentioned below., Cyclammina A (C., cf., orbicularis BRADY) Test subglobosa, umbilicate, composed of 6-8 chambers surfaces mooth; sutures distinct, somewhat depressed, nearly straight; periphery broadly rounded, aperture a long slit at base of apertural face., Diamater 0., 5-1mm., This form is distinguishable from the typical orbicularis by the smaller size and fewer number of chambers., Cyclammina B (C., cf., compressa CUSHMAN) Test nautiloid, compressed, umbilicate, composed of 16-19 chambers 10 last coil, surface smooth; sutures sometimes indistinct, not depressed, peripheral margin subacute; aperture an elongated curved sliy at base of chambers which have supplementary pores in apertural face., Diameter 5-3mm., Distinguishable from compressa by its larger form., Cyclammina C (C., cf., pusilla BRADY) Test planospiral, compressed, peripheral margin acute, slightly lobulated; chambers about 12 inlast coil; sutures distinct, nearly straight not depressed, aperture a curved slit base of apertural face., Dmameter 1-2mm., Distinguishable from pusilla by its fewer number of chambers., Cyclammina D (C., cf., complanata YABE & HANZAWA) Its related species, complanata, was originally described from the Karisan shale in Taiwan (Formosa)., The present form differs from that species by the smaller size and sinuous sutures., Cyclammina E (C., cf., bradyi CUSHMAN) This from resembles bradyi, a species widely distributed in the North Pacific, but is distinguishable by its more compressed and nearly flat chambers., Cyclammina F., (C., cf., pauciloculata CUSHMAN) This from may be identical with pauciloculata, a species which is widely distributed both in the Pacific and Oceans., Stratigraphical significance., The six forms which can be distinguished from the living species, range from the Kubiki up to the Shiiya but have not been discovered in the still younger Ushigakubi and Shiraiwa formations., Elsewhere, none of these forms have been discovered in the Pliocene age., Cyclammina C was discovered in the Miocene Mizunoya sandstone and Misawa sandstone in the Joban coal-fields., This discovery shows that the age of the Kubiki and Shiiya is Miocene, in good accordance with the age indicated by fossil mollusks., A study of the stratigraphical range of the six forms in a limited area of the oil-fields, shows that certain forms are more adundant in the Kubiki than in the Shiiya, while others are more abundant in the latter than in the former. [the rest omitted]View full abstractDownload PDF (1163K) -
George KOJIMA, Kei HIDE1949 Volume 55 Issue 640 Pages 5-8
Published: February 20, 1949
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSSyenitic aplite patches are found in biotite-hornfels at Suyama-Mura, Oda-Gun, Okayama Prefecture (Fig., 1)., These aplitic patches are mainly composed of oligoclase and orthoclase of 0., 5-1mm in size, showing the granitic texture., It is a remarkable fact that quartz is lacking in them., The biotite-hornfels consists of biotite, quartz, oligoclase and orthoclase., The mean size of the felsic constituents is 0., 005-0., 01mm., The biotite-hornfels of the district are almost equal in their petrographic features, except near the contacts of granites and porphyries., Minute pools composed of oligoclase porphyroblasts and orthoclase granules are found in the biotite-hornfels(Fig., 3)., The genesis of the syenitic aplite patches is interpreted as follows., 1., Glomeroporphyroblastic aggregates of twinned oligoclase were formed in the biotite-hornfels of argillaceous rock origin., As the oligoclase porphyroblasts grew, the orthoclase granules were combined, forming xenoblastic crystals., Quartz was removed and finally the syenitic aplite patches were formed., 2., In the course of the process, soda was added, and silica, iron, and magnesia were subtracted., A part of the materials subtracted was fixed in quartz and epidote-chlorite-veinlets in the hornfels., 3., These metasomatic changes were set in after the bulk of biotite-hornfels had been formed., The extent of the metasomatic effect in the area was as regional as that of the pure thermal effect., The metasomatism had no direct relation to the distribution of granites and porphyries indicated on the map (Fig., 2).,View full abstractDownload PDF (1226K) -
Hideo MINATO1949 Volume 55 Issue 640 Pages 9-14
Published: February 20, 1949
Released on J-STAGE: April 11, 2008
JOURNAL FREE ACCESSScorodite from various localities in Japan have been described., One from a limestone cave at Okumitate near the Mitate mine, Miyazaki Prefecture, is pale green stalactitic mass., Botryoidal scorodite was also found from the Tsunotsu mine, Shimane Prefecture and several other mines., Fine crystals of scorodite have further been obtained from contact deposits in Chichibu, Saitama Prefecture and Kitabira, Yamaguchi prefecture., The crystal faces of the mineral from Chichibu are a(100), d(120) and p(111), and those from Kitabira are a(100), b(010), d(120) and p(111)., The latter has abundant vicinal faces., A new name "aluminoscorodite" has been proposed for a mineral which has a composition intermediate between FeAsO4·2H2O and AlAsO4·2H2O., It occurs together with scorodite in a bog iron deposit at Kamikimobetsu, Hokkaido, as radiated or spherulitic aggregates of microscopic crystals., The chemical analysis will be published in another paper., X-ray powder photographs (Fe Kα) were taken.,View full abstractDownload PDF (1725K)
- |<
- <
- 1
- >
- >|