On the Petrochemical Character of the Pelitic Gneiss from the Southwestern Part in the Hida Metamorphic Belt, Central Japan

In the Hida Metamorphic Belt, metapelites develop in a small amount, in contrast to wide development of basic and calcareous metamorphites. The metapelites in the district have been clarified to be higher in CaO, FeO and MgO contents while lower in Al-excess as compared to the usual metapelite. Judged from the petrochemical characteristics and the mode of occurrence, it is probable that the metapelites in question should not be derived from rocks of "miogeosynclinal" character of higher maturity, but from those intermingled with basic volcanic materials. Also have been discussed the similarity and the difference between the metapelites from other high T-low P type metamorphic belts in Japan along with the Precambrian metapelites from the Kamiaso conglomerate

Polymetamorphism in the Hida Metamorphic Belt, Central Japan

On the western part of the Hida metamorphic belt, central Japan, there develop quartzo-feldspathic gneiss, basic gneiss and calcareous gneiss, associated with lesser amounts of pelitic gneiss. Various kinds of granite are distributed. Judged from the petrological and mineralogical characters of such meta-morphic minerals as pyroxene, amphibole, garnet, feldspar and mica, the metamorphic facies of the area is, in general, the amphibolite facies or lower. It must be noted, however, that there occur some interesting metamorphites with critical mineral associations suggesting the metamorphic facies of higher grade, probably the granulite facies. It is represented by such rocks as K feldspar-corundum gneiss (K feldspar-corundum-plagioclase-biotite-rutile), eclogitic rock (clinopyroxene-garnet-quartz) and two pyroxene gneiss (orthopyroxene-clinopyroxene-hornblende-garnet-K feldspar-plagioclase-quartz). The so-called "syenitic rock" of the Inishi type, which consists of wollastonite, clinopyroxene and plagioclase, would suggest the same metamorphic condition as that of the granulite facies rocks. Besides those critical mineral assemblages mentioned above, some minerals show the characteristics in chemical composition, which reflect the condition of higher grade metamorphism. Chemical characteristics of hornblende, garnet, plagioclase, scapolite, etc. suggest the granulite facies metamorphism in the area in question. Products of the granulite facies metamorphism are now preserved in the core parts of zoned crystals or zoned aggregates. Time and spatial relationship between the granulite facies metamorphism and the before-mentioned amphibolite facies metamorphism has been clarified in terms of polymetamorphism. In this concern, special attentions have been paid to the occurrence and mineralogy of a metamorphosed basic dyke, intruded obliquely into the surrounding gneisses. The role of granites in relation to the process of metamorphism has been summarized. Importance of the so-called "gray-granite" was especially emphasized. It is pointed out that the "gray-granite", at least a part of it, would have been formed by the process of partial melting under the condition of the granulite facies metamorphism. Meanwhile, the Funatsu granite, which had been regarded to be syntectonic and responsible for the granitization and migmatization on a large scale, has been clarified to be the post-kinematic one, playing a role of lubricunt against the blocks of metamorphites. Furthermore, uniqueness of the original rocks of the Hida metamorphites has been discussed, compared with those of the other high T — low P type metamorphic belts in Japan. Lastly, chronological analysis of the Hida Plateau revealed the presence of the older metamorphism of the granulite facies, the age of which goes back to about 500 m. y

Contact Metamorphic Effect on Basaltic Rocks by the Koyama Gabbro Complex, Susa Area, Southwest Japan

Tertiary basaltic rocks around the Koyama gabbro complex mass, which occurs in the northeastern part of Yamaguchi Prefecture, have undergone intense contact metamorphism by the mass. Radiometric age determinations indicate that the metamorphism is of Miocene age. The contact aureole is rather narrow (a maximum of about 700 m), the metamorphic grade rapidly increasing toward the mass. In the comparatively lower temperature part of the contact aureole, the metamorphic paragenesis is actinolitic hornblende ± hornblende + epidote+ biotite+ oligoclase + quartz. Meanwhile, the highest-grade rocks are represented by the stable association of orthopyroxene+ clinopyroxene ± hornblende + biotite+ labradorite + quartz. The metamorphic temperature close to the contact with the mass is estimated to be 800 to 860°C. In the most-intensely metamorphosed basalts, most of such phenocrystic minerals as clinopyroxene and plagioclase can still preserve the essential chemical characteristics in the original rocks, whereas phenocrystic orthopyroxene appears to have been chemically changed its composition during the metamorphism

Note on the Graphite-Free Corundum-K feldspar Gneiss in the Hida Metamorphic Belt, Central Japan

The association of corundum-K feldspar in a graphite-free rock is newly found in the western portion of the Hida Metamorphic Belt, central Japan. The equilibrium assemblage of the rock is corundum-K feldspar-plagioclase-biotite-apatite-zircon-ore with no graphite. Ore minerals are characterized by the abundance of rutile and by the absence of ilmenite and/or magnetite. Corundum and K feldspar had been in direct contact with each other before the formation of kelyphitic rims of muscovite aggregates around corundum crystals. The association of corundum-K feldspar in the graphite-free system must suggest the formation by the breakdown of muscovite under the condition when PH2O is not so low. Therefore, the breakdown must occur more or less near the maximum temperature expected. The metamorphic conditions have been estimated by the stable associations of zincian spinel-garnet-biotite-sillimanite-K feldspar-plagioclase and clinopyroxene-garnet in the metamorphites from the area to be around 700°C and 6 kb, which are not inconsistent with the condition deduced from the association now discussed

Nano-artifact metrics based on random collapse of resist

Artifact metrics is an information security technology that uses the intrinsic characteristics of a physical object for authentication and clone resistance. Here, we demonstrate nano-artifact metrics based on silicon nanostructures formed via an array of resist pillars that randomly collapse when exposed to electron-beam lithography. The proposed technique uses conventional and scalable lithography processes, and because of the random collapse of resist, the resultant structure has extremely fine-scale morphology with a minimum dimension below 10 nm, which is less than the resolution of current lithography capabilities. By evaluating false match, false non-match and clone-resistance rates, we clarify that the nanostructured patterns based on resist collapse satisfy the requirements for high-performance security applications

Newly Identified Oligocene Formation in the Sera Plateau, Hiroshima, SW Japan

This study aimed to show the presence of an Oligocene formation in the Sera Plateau, located in the eastern part of Hiroshima Prefecture, SW Japan, using field surveys, a petrological study, and fission-track dating. According to field surveys conducted between 1996 and 2002, and supplementally in 2017, rhyolitic pyroclastic rocks and conglomerate beds unconformably covered by the Quaternary sediments were identified along the bank of Mihara-gawa River at Kurohada in Sera Town. The rhyolitic pyroclastic rocks, tentatively called Kurohada Ryolite, were composed of welded tuff, coarse tuff, and tuff breccia, and were intercalated with conglomerate beds lithologically similar to the mountain gravels. The Kurohada Rhyolite and the conglomerate beds were either horizontal or dipped gently to the northwest, with a total thickness of about 5 m. Based on whole-rock chemical composition analysis by X-ray fluorescence (SiO2: 72.39-75.82 wt % , K2O+Na2O: 5.78-7.80 wt % ) the welded tuff was classified into rhyolite of sub-alkalic series. Under the microscope, the pyroclastic rocks were composed of crystal fragments of plagioclase and quartz, and lithic fragments in glassy matrix, and signs of thermal alteration could not be confirmed. On the other hand, one of the lithic fragments of rhyolite contained biotite fine crystals as thermal metamorphic products. Thus, the Kurohada Rhyolite was distinguished from the Mesozoic Takada Rhyolites distributed widely in Hiroshima Prefecture depending on the presence of thermal metamorphism. Fission track ages of zircons from the welded tuff were 30.4 ± 1.6 Ma and 30.9 ± 1.5 Ma. This result shows that the geologic age of Kurohada Rhyolite and associated conglomerate beds in the study area is constrained to the early Oligocene and suggests the possibility that the mountain gravels distributed in the eastern part of Hiroshima Prefecture are Paleogenic.This study was partly supported by JSPS KAKENHI Grant Number JP16K00966

The Creation of School Education Bringing up a Student Carrying Tomorrow (3) : The Valuation of "Compulsory Subjects", "Optional Subjects", and "Integrated Subjects"

The purpose of this study is to show the valuation of "Compulsory Subjects", "Optional Subjects", and "Integrated Subjects", to show the relationship between each subjects and "three abilities", "the ability of recognizing othere senses of value", "the ability of self-expression and communication" and "the ability of decision-making" which defined by the project members. The main result of this study is that we should make up the standards which teachers, students and parents recognize as important abilities