Tuff Breccia Research Articles

北海道に産出する二,三の二酸化マンガン鉱物とその産状

The manganese mineralization occurred in three ages in Hokkaido. The older one is of Palaeozoic or Mesozoic ages, and the younger two of Miocene and Quaternary. Late Tertiary, especially the Miocene age is characterized by the most intensive and extensive volcanic activities. The mostly ore deposits are found this age and the only south-western Hokkaido.The writer investigated the various modification of manganese dioxide and hydroxide minerals mainly from the mineralogical stand point and clarified of geological occurrence in late Tertiary. Some geologists suppose that the deposits are syngenetic ore beds precipitated from marine water, the manganese of which were supplied from manganese-bearing hot springs. But others postulate the hydrothermal replacement origin.Manganese dioxide or hydroxide is one of the most familiar and common minerals found in various manganese deposits, but is mineralogical study is very equivocal owing to the variability and overlapping of physical properties and chemical composition. It is obvious, in Hokkaido, that they always occur in a fine grained massive state, and comparises several modification. Some members well crystallized but other a very poorly crystallized.The writer found pyrolusite, manganite, cryptomelane, ramsdellite, birnessite and ranceite in Hokkaido. Ramsdellite has not been found in Japan, but it was found in fissure of Palaeozoic red chert from the Tanno mine, Kitami District in Hokkaido. Birnessite and ranceite are found in manganese wads from the Komagadake mine.The manganese dioxide deposits in Hokkaido are found concordantly or slightly obliquely to the stratification in Miocene green tuff, tuff breccia, and shale. The modes of occurrence of many manganese dioxide deposits are controlled by geological structure : the deposits are distributed at special portion as small basin. A somewhat sedimentary cycle was given to explain the distribution of manganite → pyrolusite to upper bed from lower bed. These phenomena are applicable for the prospecting of the so-called Pirika type manganese dioxide deposits.Some manganese oxide mineral specimens show under a rate heating, a characteristic type of differential thermal analysis curve. Natural manganese dioxide and hydroxide ores were aggregates of some manganese·minerals. The application of differential thermal analysis to this group of mineral provides valuable information invaluable by other standard method of technique.In this paper, the results of mineralogical and geological distribution researches on these deposits are summarised.

On the Neogene Formations in the Vicinity of Fukuoka-machi, Iwate Prefecture

Cenozoic formations, found along the northern border of the Kitakami Mountains, are marginal deposits of the so-called Uetsu geosyncline. A detailed study of stratigraphy and geologic structure of Neogene Shiratorigawa group which is the lower portion of the above Cenozoic formations, are reported.1) The Shiratorigawa group overlies the basement Paleozoic and plutonic rocks with a remarkable clino-unconformity, and is divided into the following three formations in descending order:Suenomatuyama formation (100-150 m) : mostly composed of tuffaceous sandstone, with two-pyroxene andesites and their pyroclastics in the upper horizon. Pectinid and other molluscan remains are abundant.Kadonosawa formation (50-100) : mainly composed of siltstone accompanied by thin conglomerate and sandstone beds in its basal horizon. The molluscan remains are abundant in its upper and basal horizons.Yotuyaku formation (150-250 m) : chiefly composed of siltstone and sandstone with lenticular conglomerate beds. An intercalation of the andesitic tuff breccia is found in its middle horizon. Plant and molluscan remains are present.These three formations are subdivided into several members.2) The basement rocks are exposed in two masses, at the eastern margin and the southwestern corner of this district, and the depression between the two masses is filled up by the Neogene formations. Geologic structure of this district is best considered as consisting of the following three subdivisions :1. Southern area or the Namiuchi-toge syncline ; the axis of the syncline dips to the northwest direction.2. Central area or the Maisawa basin structure ; a semicircular shallow basin with a westward opening.3. Northern area ; gentle monoclinal structure, dipping in west to northwest direction.In addition to the areal structures mentioned above, weak undulations and small faultings are observable. In general, structural trend of N 30°W in the Neogene formations prevails in this district. This is due to the structural trends of the basement rocks.3) Shapes of the sedimentary bodies of each formation or member are illustrated in the isopachous contours.4) The relationship between the Kadonosawa and the Suenomatuyama formations is conformable in general. A partial unconformity, however, can be recognized between the two. Near the eastern margin of the basin, crests of the undulation of the Kadonosawa formation are eroded out and covered by the basal conglomerate of the Suenomatuyama formation with unconformity.5) The Nisatai dacite extruded probably during or after the deposition of the upper members of the Suenomatuyama formation.

On the iron ore and associated deposits of the Asari Mine, environs ot Otaru City, Hokkaido.

The iron deposits of the Asari mine, located about 15km south of Otaru city, shiribcshi province, Hokkaido, are of hydrothermal origin. In this area liparitic tuff and green tuff breccia sediments of the Miocene formation have been intruded by liparite and andesite, and andesite, and later covered by flows of andesite lava. The iron ores are generally irregular, massive deposits within the liparitic tuff and liparite. These ore bodies consist of brown iron ore and some blackish iron ore. Ore and associated minerals are quartz, goethite, lepidocrosite, limonite and pyrite. The blackish iron ore is bluish black, and gives a reddish black streak. In polished section, shis iron ore consists of the zonal concentric textare of goethite and lepidocrosite. It's x-ray powder pattern is very similar goethite and hydrohematite (turite), but the thermal differential analysis shows mixed characters of goethite and lepidocrosite.

A New Pleistocene Bighorn Sheep from Arizona

The junior author with the assistance of three other students in the summer of 1949 made a study of Catclaw Cave in Mohave County, Arizona. The cave is in the Black Canyon of the Colorado River, fifteen miles downstream from Hoover Dam and one mile upstream from United States Geodetic Survey Cable No. 17 (Fig. 1, Loc. F:2:l, Catclaw Cave). It lies two hundred yards east of the river on the south side of a small unnamed tributary, and is approximately 45 feet above the Colorado River. The cave is now covered by Lake Mohave which is formed by the Davis Dam. The excavation was done under the auspices of Dr. Emil W. Haury, Department of Anthropology, University of Arizona. The formation of the cave was the result of an intermittent tributary of the Colorado River cutting through a dike of volcanic tuff breccia. This cutting had left...

On the Geologic Structure and the Volcanic Activity of Himesima, Oita Prefecture

Himesima, small island situated near the western border of the Inland Sea., B., KOTO'S paper the Volcano of Japan (1916) has attracted the attention of many petrologists concerning the volcanic rocks in this island., Since the publications, though a few works on the petrology of the volcanic rocks has been reported by the other authers, but no study has been published from the stratigraphic point of view., The present paper is chiefly devoted to the description of the late Cenozoic sediments of this island, with special reference to the geologic structure and the age of the volcanic activity The stratigraphic sequence is summarized as follow: Himesima volcanics and tuff breccia unconformity Himesima formation Karato member (70m+) Maruisihana member (60+) Basement rock unexposed The Maruisihana member contains conspicuous amounts of pyroclastic materials and the uppermost part consist of a thick volcanic conglomerate, by which the Himesima formation is divided in to two members., These materials contain bear hornblend-andesite which is characteristic in the Sanin Volcanic Zone., On the contrary, the Karato member consists of an alternation of sand and mud containing little pyroclastic materials., The Himesima formation may be correlated with the neighbouring Turusaki formation which is considered to be early Pleistocene (I2) in age., The geologic structure of the Himesima formation is characterized by the marked folding with axes running nearly N-S direction., Some parts are remarkably modified by the volcanic bodeis intruding anlong the anticlinal axes as shown in Fig., 3., The Himesima volcanics and tuff breccia rest on the Himesima formation unconformably and build up five cones., The age of this activity may be assigned to late Pleistocene (J2∼J3).,

GLENDORA VOLCANIC ROCKS, LOS ANGELES BASIN, CALIFORNIA

The Los Angeles Basin in southern California is filled with locally derived Cenozoic rocks probably exceeding 25,000 feet in maximum thickness. Marginal facies of some of these sediments are exposed in and near the foothills of the San Gabriel Mountains from west of Glendora to the vicinity of Pomona, Los Angeles County, where they either rest on or are interbedded with volcanic rocks. These last, the Glendora volcanics, consist of massive and autobrecciated basalt, calcic andesite, andesite, dacite(?), and rhyolitic lavas, and an approximately equal volume of interbedded tuffs and tuff breccias. Among both flows and pyroclastics andesitic compositions predominate. Similar rocks encountered in wells in the eastern half of the Basin are considered part of the same series. The later members of the Glendora volcanics are interbedded with middle Miocene marine sediments; the earlier representatives are probably not older than Miocene and may increase in age toward the center of the Basin. Maximum known thickness occurs in wells and exceeds 3500 feet. The exposed Glendora volcanics here studied constitute but a small, much-faulted and eroded remnant of a volcanic field whose original extent was probably at least 35 miles from north to south and almost as much from east to west. Local evidence shows that part of the northeastern shore of the middle Miocene sea passed through the mapped area. Considerable volumes of andesitic tuff breccia containing, on the landward side, numerous large blocks with what are interpreted as radial cooling cracks are believed to be the deposits of several eruptions of nuee ardente type. The fact that within an 8- by 9-mile rectangle more than 20 varieties of volcanic rock are exposed in less than 8 square miles of outcrops seems to indicate a considerable number of small vents or a few remarkably versatile sources. The scene may have resembled Vesuvius and the Phlegraean Fields bordering the Bay of Naples. Fourteen new chemical analyses of members of the volcanic series emphasize their general andesitic character and notably low K2O and ferromagnesian constituents.

On the Green tuff geology of the southwestern foot of Kurikoma volcano and the origin of the Sanzugawa, Onikobe Uppermost Miocene basins

The Neogene sediments in the region bodering Akita, Yamagata and Miyagi Prefectures on the southwestern foot of Kurikoma valcano are classified into following formations; these in ascending order are the Kamuroyama, Torageyama and Sanzugawa formations in the Sanzugawa basin, Akita Prefecture and the, Kanisawa, Torageyama, Akasawa and Miyazawa formations in Onikobe besin, Miyagi Prefecture. Those two lower formations in each basin are thought to be correspond to the so-called Green tuff developed extensively in the backborn ranges between Akita and Iwate Prefectures to the east of Yokote basin and also between Yamagata and Miyagi Prefectures to the east of Shinjo basin, and consist of a heavy accumulation of green tuff and tuff breccia acconpanied by propyritic lavas. These formations are unconformably overlain by the remarkable lacustrine deposits of the above-cited upper formations which are fairly well developed in the viscinity of Sanzugawa or Onikobe along the upper streamside of the Takamatsu or Arao River. The fossil flora from the Sanzugawa and Akasawa formations suggest the Uppermost Miocene in age. And the origin of the Paleo-Sanzugawa and Paleo-Onikobe basins of authors is thought to be related with the Uppermost Miocene lake formed by the crustal deformation in the backborn ranges of Northern Honshu, for which Prof. Hanzawa has initiated the name of Paleo-Sendai Lake (S. Hanzawa, 1950).

On the Mesozoic tuffaceous rocks in the Kammon District

The Mesozoic beds in the Kammon district, which have been denominated the Suzuriishi series, are divided into two subgroups; Wakino and Shimonoseki. The both contain a large quantity of tuff aceous rocks and are classified into several kinds as follows; (A) Red and green tuffaceous rocks, (I) Red and green calcareous shale (2) Red and green tuffaceous shale or sandstone, (3) Red and green lithic tuff. (4) Red and green lithic tuff or lapilli tuff, (5) Volcanic breccia, (B) Dark-colored tuffaceous rocks (6) Black tuff breccia or volcanic breccia, (7) Black lithic tuff, etc. They are characteristic in geological and petrographical properties and in chemical compositions.

Relation between the geology and the growth of Cryptomeria there-on in the Kaneyama district, Yamagata Prefecture

This paper deals with the relation between the geology and the growth of Cryptomeria there-on in the Kaneyama district, Yamagata Prefecture. The surface geology of the district is classified, from agricultural and forestrial standpoints, as: A Two Pyroxene andesite and its agglomerate with their loose decomposition products thickly developed on the surface, B Breccia tuff and pumiceous tuff with some blocks of “A” in the overlying soil, C Breccia tuff and pumiceous tuff with some blocks of hypersthene andesite in the overlying soil, D Breccia tuff and pumiceous tuff without other blocks in the soil, E Pumiceous clayey tuff, tuffaceous shale and fine clayey tuff. The development of Cryptomeria is best on A, next on B and C, and worst on E. On D, it is assumed from few data, the development is worse than on B and C, but is better than on E. No definite relation is found between the growth of the tree and the direction of the slope.

Development of the Oshima Island

Under the Oshima Volcano sits ruin of basaltic volcano named Okata basalts. Under the Okata basalts, it is believed to exist miocene volcanic complex (Yugashima Series) as the fragments of altered andesites and gabbro are contained in the tuff breccia. The Okata basalts is composed in pliocene epoch as strato-volcano. After it is folded, faulted and eroded deeply, the activity of the Oshima Volcano began covering the reef of ruined Okata basalts exposed on the surface of the pacific ocean in quaternary epoch.The volcanism succeeded violently intercalating peaceful time, when the pre-historic man lived at the sea shore, and at last, after the flow out of large quantities of lava, caulderon subsidence of the top of the volcano occurred. Before the subsidence, fault in the direction of N-S was formed along the east coast of the island, which is now represented as cliff of about 100 m in height. And also, accompanying the subsidence, fault was formed at the north part of the caldera in the direction of NE-SW to obscure the oval form of the caldera.After the subsidence central cone Miharayama began its development. The broad crater named “Inner Somma” seems to be formed in the pre-historic time and the historic activities occurred in it to form narrow vents or small cinder cones here and there in each case. The violent activities to flow lava over the wall of “Inner Somma” occurred only two times in the record and the recent activity is the third case.

Mineralogy of Green Tuff Breccia near Shiroishimachi, Miyagi Prefecture.,

Mineralogy of Green Tuff Breccia near Shiroishimachi, Miyagi Prefecture.,

The Glendora Volcanics: ABSTRACT

The term Glendora volcanics has been given to the series of volcanic rocks exposed in the northeastern San Gabriel basin, Los Angeles County, California. They consist of flows, tuff breccias, and tuffs ranging in composition from olivine basalt to glassy rhyolite or dacite, the most abundant being andesitic flows and pyroclastics. Thicknesses reach at least 2,000 feet in exposed sections and about 3,500 feet in wells. Luisian Foraminifera and fish scales from sediments interbedded with upper members of the volcanics indicate that they are probably largely of upper middle Miocene age. End_of_Article - Last_Page 2088------------