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Volume 20 (1970)
- Issue 104 Pages 361-
- Issue 103 Pages 315-
- Issue 102 Pages 267-
- Issue 101 Pages 211-
- Issue 100 Pages 69-
- Issue 99 Pages 1-
Volume 20, Issue 102
Displaying 1-6 of 6 articles from this issue
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Setsuji OHTA, Masami AKATSUKA, Tanio HONDA1970 Volume 20 Issue 102 Pages 267-275
Published: September 07, 1970
Released on J-STAGE: December 14, 2009
JOURNAL FREE ACCESSThe Tsumo Mine, one of the pyrometasomatic Cu-Pb-Zn deposits, is in the inner zone of the south-western Japan.
In this paper, we report the outline of geology, ore deposits, and the prospecting program and its result.
The geology consists of Palaeozoic sediments, (slate, sandstone, quartzite, limestone and green rocks in ascending order), and late Cretaceous or early Tertiary acidic igneous rocks.
The Palaeozoic formations cover the main part of the area, generally forming an anticlinorium with low angle NE plunge, and with complicated structures, by minor folds and faults.
Main igneous rocks are acidic effusive rocks, spreading over the SE part of the area, and the Masago-granitic complex, intruding into the core of the main anticline or along the fault zones.
A favorable conditions for mineralarization were considered to be the superposition of followings :
1) Presence of calecareous beds (banded or transitional facies).
2) Complicated folding area of the favorable beds (cross fold).
3) High density area of fissure systems.
4) A vicinity of the Masago-granitic complex (especially, fractured acidic dykes).View full abstractDownload PDF (639K) -
Yuichi SUZUKI1970 Volume 20 Issue 102 Pages 276-294
Published: September 07, 1970
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSThe Akatani Mine is a hydrothermal-metasomatic iron and copper deposit. Paleozoic formation and Cretaceous granodiorite, lower Miocene volcanic rocks and middle Miocene sedimentary rocks are distributed in the Akatani Mine area. The ore deposits have two periods of mineralization. The first mineralization, which is related to the intrusion of the granodiorite, occurred in the Paleozoic limestone. Skarn minerals are composed mainly of hedenbergite, lievrite, wollastonite, epidote and garnet with some sphalerite and galena. The second mineralization, which formed main ore deposits in this mine area, occurred along the faults and shear zone in the Paleozoic limestone and in some places near the boundary between limestone and other Paleozoic rocks at the last stage of strong acidic volcanism with some basic volcanism of the lower Miocene in age.
Ore minerals are hematite, magnetite, chalcopyrite, pyrite, galena and sphalerite. The wall rock alteration of the second mineralization are dolomitization, chloritization, sericitization, kaolinitization and silicification. The copper deposits contain always hematite and some magnetite.View full abstractDownload PDF (4309K) -
Norihisa HAYAKAWA, Shunichi SUZUKI1970 Volume 20 Issue 102 Pages 295-305
Published: September 07, 1970
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSThe Miocene formations in the Tadami area are chiefly composed of pyroclastic and volcanic rocks. Among them rhyolitic vitric tuffs of the Fuzawa formation are extensively altered to zeolite rocks with white colour. Volcanic glass in these tuffs is largely altered to zeolites, associated with opal, montmorillonite and secondary quartz, though the crystal fragments of feldspar and biotite are unaltered. Clinoptilolite and mordenite are the principal zeolites in the altered tuffs. Ferrierite also occurs as an alteration product of the volcanic glass. Glass shards are replaced by microcrystalline ferrierite and the vitroclastic texture is still preserved. The X-ray powder diffraction data of this ferrierite agrees well with that of ferrierite from Kamloops Lake, British Columbia.
Ferrieritized tuffs are rarely intercalated as irregular thin bands or lenses in mordenitized tuffs of the lower part of the Fuzawa formation. Macroscopic and microscopic features of ferrieritized tuffs are similar that of mordenitized and clinoptilolitized tuffs.
Ferrierite is a rare zeolite, which has been found so far only in cavity fillings in basaltic and andesitic rocks. Ferrierite from this area suggests its new mode of occurrence as a diagenetic alteration product of vitric tuff.View full abstractDownload PDF (2624K) -
Tetsuya SHOJI1970 Volume 20 Issue 102 Pages 306-309
Published: September 07, 1970
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSFrom the investigation of 20 samples of garnets from the Shinyama ore deposits of the Kamaishi mine by means of the decrepitation method, the writer concludes as follows.
(1) The logarithmic expression of the decrepitation frequency shows a linear relation to the temperature at the neibourhood of the knick point of the decrepigraph. The decrepitation temperature of garnet, which is the lowest temperature on the straight line, does not relate to the distance from the igneous body.
(2) There are two types of the decrepitation patterns. The chemical compositions of both types are nearly the same (And50 Gr50-And30 Gr70, determined by X-ray powder patterns). The type I garnet does not decrepitate frequently (less than 15 counts/sec) and is found in the barren skarn zone. On the other hand, the type II decrepitates frequently (more than 30 counts/sec) and is found in the ore bodies.View full abstractDownload PDF (223K) -
1970 Volume 20 Issue 102 Pages 309-312
Published: September 07, 1970
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSDownload PDF (276K) -
1970 Volume 20 Issue 102 Pages 312-313
Published: September 07, 1970
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSDownload PDF (162K)
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