The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists最新文献

{"title":"Mantle metasomatic enrichment in LILE of basalt magma sources beneath the Northeast Japan arc, as indicated by the LILE/Y-Zr/Y plots","authors":"O. Ujike","doi":"10.2465/GANKO1941.82.245","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.245","url":null,"abstract":"The Nb/Y-Zr/Y plot implies that, before mantle metasomatism, magma sources for NE Japan arc basalts were more depleted in incompatible elements as a result of previous extraction of magmas than those for the N-type mid-oceanic ridge basalts. The LILE/Y-Zr/Y plots imply that the NE Japan arc basalts are derivatives from mantle regions metasomatically enriched in LILE probably by fluids released from the subduction zone. The degree of alkali (Rb and K) enrichment is lower in the trench side than in the back-arc side, but that of Sr enrichment is higher in the trench side. The alkalic volcanism in the back-arc region, with the exception of that belonging to the Chokai volcanic zone, is affected by mantle metasomatism to limited extents.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"19 1","pages":"245-256"},"PeriodicalIF":0.0,"publicationDate":"1987-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81427575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salt crystallization decay and water-rock interaction of rock-cliff Budda sculptures at Yakushido Temple of Odaka Town, Fukushima, Japan","authors":"Y. Seki, T. Hirano, Kunio Watanabe","doi":"10.2465/GANKO1941.82.269","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.269","url":null,"abstract":"Rock-cliff Budda sculptures of Odaka Town, Fukushima Prefecture, Japan were carved about one thousand years ago on the Neogene dacitic tuffaceous sedimentary rocks. These sculptures have been badly decayed by (1) the formation of scabs composed chiefly of gypsum, epsomite and thenardite with subordinate amounts of kogarkoite, langbeinite, zoherite, hydroglauberite, starkeyite, jurbanite, loeweite, hexahydrite, alunogen, mirabilite, glauberite, syngenite, hemihydrite and sylvite at the surface of the sculptures by the evaporation of groundwater percolated through the voids and joints in the Neogene volcanogenic sedimentary rocks and (2) the exfoliation of the these scabs and near-surface part of Neogene sedimentary rocks, particularly due to the heaving during the freezing-thawing cycle of seeped groundwater in winter season.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"35 1","pages":"269-279"},"PeriodicalIF":0.0,"publicationDate":"1987-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82872853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distributions, paragenesis and fluid inclusions of hydrothermal minerals in the Kakkonda geothermal field, Northeastern Japan","authors":"Y. Muramatsu","doi":"10.2465/GANKO1941.82.216","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.216","url":null,"abstract":"Distributions, paragenesis and fluid inclusions of hydrothermal minerals in the Kakkonda geothermal field, Northeastern Japan, were studied by means of the X-ray diffractometry and the microthermometry. Many veinlets are found in Tertiary sedimentary rocks and welded tuff of the Pliocene-Pleistocene. The mineralization can be divided into three paragenetic stages: Stage IA, Kfeldspar+quartz+pyrite; Stage IB, quartz+calcite+laumontite+yugawaralite+stilbite+mordenite+pyrite; and Stage II, calcite+kaolinite+quartz+pyrite. Minerals in Stage II were formed from recent geothermal fluids. Fluid inclusions in quartz and calcite are generally several microns in size and are liquid inclusions. Homogenization temperatures of fluid inclusions in quartz and calcite range 87-296°C and 83-217°C, respectively. Judging from the distribution of the maximum homogenization temperatures obtained for the samples from geothermal wells (Muramatsu, 1984) and the surface, it is inferred that at least 900 meters of overburden were eroded after the mineralization. Temperature distribution pattern around the Kakkonda geothermal field suggests that high temperature fluids ascended mainly from the deeper zone of the western area, and that some meteoric water descended from the central area at Stage I and Stage II (present day). The data on the modes of occurrence, and the distribution pattern and fluid inclusion data of quartz and calcite, indicate that most of quartz were deposited from ascending fluids in the convective geothermal system, and that calcite precipitation resulted partly from the boiling of ascending hydrothermal fluids in the vicinity of the surface.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"50 1","pages":"216-229"},"PeriodicalIF":0.0,"publicationDate":"1987-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88915282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A simple statistical test for fission track counts obtained by the grain-by-grain dating method","authors":"M. Hayashi, H. Sugiyama","doi":"10.2465/GANKO1941.82.239","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.239","url":null,"abstract":"A simple statistical procedure is proposed for testing the validity of fission track counts obtained by the grain-by-grain dating method. This is based on the principle that the standard deviation of grain ages for a set of counting data should be 1 after they are standardized. Accordingly, the F value (actual variance/expected variance) will be close to 1, when the dating experiment is carried out precisely and no detrital grains of older ages are included. This test, therefore, makes it possible not only to evaluate the precision of dating experiments but also to eliminate the data pertaining to detrital grains contained in volcanoclastic rocks.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"47 1","pages":"239-242"},"PeriodicalIF":0.0,"publicationDate":"1987-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76264039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salt crystallization decay of the rock-cliff Budda sculpture and water-rock interaction at Daifukuji Temple, Tateyama, Chiba, central Japan","authors":"Y. Seki, H. Sakai","doi":"10.2465/GANKO1941.82.230","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.230","url":null,"abstract":"Daifukuji Temple rock-cliff Budda sculpture which is located halfway up on the hill near the coast of Tateyama, Chiba Prefecture was carved in 8th century on the Neogene andesitic tuff and tuff breccia alternated bed. It is sheltered by a beautiful wooden construction. The Neogene andesitic tuff and tuff breccia are composed chiefly of augite, hypersthene, hornblende, plagioclase, and volcanic glass with subordinate amounts of fine-grained magnetite, pyrite (probably biogenic), hematite and limonite. The surface of Budda sculpture is covered by a thick, up to several mm, crust or scab composed chiefly of minerals such as gypsum, thenardite, epsomite, mirabilite with minor amounts of halite, sylvite, aragonite and copiapite. Rain water penetrates into the rock of the hill where sculpture is located and the water easily comes out after interaction with rocks and evaporates from the surface of rock-cliff. The water coming out from rock mass has high contents of Ca, Na, Cl, HCO3 and SO4 with subordinate amounts of K and Mg. Gypsum-rich scab or crust was formed by the evaporation of such type of groundwater on the rock-mass surface. The growth of thus formed scabs or crusts and their falling off must be major reasons why the sculpture has been decayed so badly as shown by Fig 4. Modes of occurrence of gypsum-rich scabs and indoor experiments using bore-hole cores taken from the Neogene volcanogenic sediments mass on which the sculpture was carved indicate that the increase in the thickness of the gypsum-rich scabs is unbelievably fast, probably more than 0.15mm/year. The repeated cycle of the growth of gypsum-rich scab or crust on the surface of Neogene volcanic sedimentary rock mass and their falling off should be stopped to prevent the forth decay of this Budda sculpture. The best ways to solve this problem are considered to be (1) to minimize the down permeation of groundwater from the top surface through interstitial void and joint of Neogene volcanogenic formation by making open drainage space at the above and/or back side of the rock-cliff sculpture or by covering the top surface of the hill by unpermeable facing and (2) to keep the humidity of the room of rock-cilff sculpture as high as possible to minimize the evaporation of water extracted from the surface of the sculpture.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"16 1","pages":"230-238"},"PeriodicalIF":0.0,"publicationDate":"1987-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84151231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystal-chemical studies on the immiscibility phenomena in the NaCrSi2O6-CaMgSi2O6 pyroxene system","authors":"H. Ohashi, T. Fujita","doi":"10.2465/GANKO1941.82.211","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.211","url":null,"abstract":"The crystal structure of (Na.45Ca.55) (Cr.45Mg.55) Si2O6 pyroxene synthesized at 1200°C and 2.2GPa has been refined by the least squares method using 751 reflections measured with an automatic single crystal diffractometer. The weighted R factor is 0.030 for 642 observed reflections. The cell dimensions are: a=9.645A, b=8.821A, c=5.254A, β=106.47°, and V=428.67A3; space group C2/c. Comparison of a new crystal structure refinement for the (Na.45Ca.55) (Cr.45Mg.55)Si2O6 pyroxene with the published refinements for five clinopyroxenes in the system NaCrSi2O6-CaMgSi2O6 indicates that the O1A1-M1-O1B2 angles correlate with the M1-O1A1 distance as two different trends reflecting the repulsion effect between the O1 oxygens and the non-bonding 3d electrons of the Cr3+ ion. The repulsion effect exists in the NaCrSi2O6 side of the miscibility gap in the system NaCrSi2O6-CaMgSi2O6, in which the Cr3+ ion occupies a smaller octahedral site. On the other hand, the repulsion effect does not exist in the CaMgSi2O6 side, in which the Cr3+ ion occupies a larger octahedral site.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"29 1","pages":"211-215"},"PeriodicalIF":0.0,"publicationDate":"1987-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83502129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"K-Ar age of the tuff breccia from Yamagata-mura, Kunohe-gun, Iwate-Prefecture","authors":"K. Kubo","doi":"10.2465/GANKO1941.82.203","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.203","url":null,"abstract":"Tuff breccia was found in Yamagata-mura, Kunohe-gun, Iwate-Prefecture. This tuff breccia contains many granitic and andesitic rocks with a small numbr of chert fragments. The matrix part of the tuff breccia is characterized by the presence of coarse, euhedral or corroded hornblende crystals. K-Ar age of the hornblende is dated as 16.1±2.0 Ma, and therefore, the tuff breccia is considered to be formed at the Middle Miocene in age. At the northern Kitakami Mountains, the area of Neogene magmatism should have been more extended 10 km to the east than that was considered before.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"36 1","pages":"203-206"},"PeriodicalIF":0.0,"publicationDate":"1987-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82041629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The petrology of the Chuquicamata Plutonic Complex, Chile","authors":"M. Parada, I. Aracena, Hisao Tanaka","doi":"10.2465/GANKO1941.82.177","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.177","url":null,"abstract":"The Tertiary Chuquicamata Plutonic Complex, in which the Chuquicamata porphyry copper deposit occurs, is described from petrographical and mineralogical viewpoints. The complex is composed of the Fortuna Monzonite, Chuqui Granite Porphyry and Este Monzogranite. The Chuqui Granite Porphyry, the host rock of the mineralization, is divided into the porphyry I, II and III. Potassic, propylitic and phyllic alteration of varying degrees prevails throughout the complex. Amphibole from the Fortuna Monzonite, the most basic rock type, has Mg/(Mg+Fe*) ratios higher than 0.74 and high Si atoms. Biotites contained in all the rock types exhibit Mg/(Mg+Fe*) ratios higher than 0.58. The high Mg/(Mg+Fe*) ratios of the mafic silicates, high Fe2O3/FeO whole rock ratios, the presence of magnetite and high magnetic susceptibility indicate that the Chuquicamata rocks were formed at high oxygen fugacities between the Qz-Mt-Fa and Mt-Hm oxygen buffer reactions. Two-feldspar geothermometer of Stormer (1975) gave fairly low equilibration temperatures from 550° to 350°C. The lowest temperatures were obtained for the twofeldspar pairs from the porphyry I, which is consistent with the lowest TiO2 contents of their biotites. The early plagioclase crystallization in the Fortuna Monzonite, and the quartz crystallization before biotite in the Chuqui Granite Porphyry imply that the Chuquicamata magmas were not saturated with H2O throughout their entire congelation. Because only a little amount of magmatic fluid is available, the presence of meteoric fluids is speculated for the cause of the hydrothermal alteration and subsolidus equilibration.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"4 1","pages":"177-188"},"PeriodicalIF":0.0,"publicationDate":"1987-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89785115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of free volume in the viscous behavior of magma.","authors":"H. Taniguchi, T. Murase","doi":"10.2465/GANKO1941.82.189","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.189","url":null,"abstract":"In the present study, the effects of free volume on the viscous behavior of magmatic melts are discussed on the basis of free-volume theory. The most important conclusion is that the change of viscosity with temperature, pressure, and composition is related approximately to the change of free volume in the melts. It has been found that an increase of temperature and mafic components induces an increase of free volume in magmatic melts, and it is well known that they also tend to cause a decrease of viscosity. The relation between free volume and viscosity is interpreted as a reflection of the greater ease of movement of constituent units in melts that have more interstitial space. Pressure effects on viscosity are also interpreted as fundamentally based on the change of free volume. Melts having an abundance of free volume at 1 atm are depolymerized melts and show an increase of viscosity with pressure owing to a decrease of free volume. On the other hand, in polymerized melts having a small free volume at low pressures, the controlling process of viscous flow is not the change of free volume but making or breaking of bonds between constituent units of the melt. Sharma et al. (1979) suggested on the basis of Raman spectroscopy that the decrease of viscosity of polymerized melts at high pressures was caused by deformation of constituent unit accompanying the weakening of Si-O-Si bond. Our explanation of the behavior of polymerized melts is in harmony with their interpretation.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"1 1","pages":"189-202"},"PeriodicalIF":0.0,"publicationDate":"1987-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90078244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Progressive deformation and annealing of quartz inclusion in porphyroblastic feldspar during synmetamorphic non-coaxial deformation","authors":"M. Toriumi","doi":"10.2465/GANKO1941.82.123","DOIUrl":"https://doi.org/10.2465/GANKO1941.82.123","url":null,"abstract":"A single crystalline inclusion in a single crystalline porphyroblast of metamorphic tectonites is deformed to an ellipsoid. The rate of shape change of ellipsoidal inclusion is controlled by the rounding process driven by reduction of the interfacial free energy and the deformation process of the ellipsoidal inclusion caused by deformation of host porphyroblast during synmetamorphic progressive deformation. In this paper, the model for shape change of inclusion mineral during contemporaneous deformation and annealing is proposed in the two dimensional case. It is concluded that the critical grain size of spherical inclusion is possibly defined in a function of strain rate in this model. The application to the Sambagawa and Ryoke metamorphic rocks clarifies that the strain rate of the former is much higher than that of the latter by two orders of magnitude.","PeriodicalId":22709,"journal":{"name":"The Journal of the Japanese Association of Mineralogists,Petrologists and Economic Geologists","volume":"84 1","pages":"123-131"},"PeriodicalIF":0.0,"publicationDate":"1987-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79377314","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}