ヒガシ ナンキョク ナピア オヨビ レイナー ガンタイ ニオケル ニホン ナンキョク チイキ カンソクタイ チシツ グループ ノ カツドウ セイカ ノ ソウカツ ト コンゴ ノ カダイ

東南極エンダビーランドに分布するナピア及びレイナー岩体を対象とした,日本南極地域観測隊地質グループによるこれまでの調査研究の成果として,1)野外調査による詳細な地質図の公表,2)ナピア岩体の原岩構成と形成年代の特定,3)超高温変成作用の変成条件と年代の精密解析,及び4)苦鉄質岩脈群の区分と活動時期の特定,の4項目について紹介した.これらの成果を踏まえた今後の同岩体の調査研究課題として,1)ナピア及びレイナー岩体のテクトニクスの解明: 新しい視点による広域調査の重要性,2)太古代大陸地殻の形成過程の解明,3)太古代後期原生代初期の超高温変成作用のテクトニクスの解明,4)EM型の起源物質のダイナミックスとスーパープルームのテクトニクスの解明,及び5)大陸地殻の成長と離合集散プロセスの解明: 船上地磁気・重力観測,の5項目について具体的な調査地域をリストアップして提言した.Scientific activities and results of the JARE (Japanese Antarctic Research Expedition) geology group for the Napier and Rayner Complexes in Enderby Land, East Antarctica, are reviewed in relation to 1) publications of two detailed geologic maps as a result of field work, 2) characterization of protoliths, and determinations of their formation ages, 3) precise analyses of metamorphic conditions, and age determinations of ultra-high temperature (UHT) metamorphism, and 4) classification of mafic dike swarms, and specification of their activities. On the basis of these activities and results, recommendations are made for research localities to make clear 1) the tectonics of the Napier and Rayner Complexes, 2) formation processes of Archaean continental crusts, 3) roles of UHT metamorphism of Archaean to Proterozoic ages, 4) dynamics of enriched-mantle type of source materials, and implications for related super-plume tectonics, and 5) growth histories of continental crusts, and processes of their amalgamation and separation

A complex of rab3A, SNAP-25, VAMP/synaptobrevin-2 and syntaxins in brain presynaptic terminals

AbstractTwo monoclonal antibodies (SPM-1 and SPM-2) immunoprecipitate brain N-type calcium channels. On immunoaffinity chromatography of digitonin extracts of bovine brain membranes on SPM-1- and SPM-2-Sepharose, proteins of 36 (syntaxins A and B), 28 and 19 kDa are specifically retained by both columns. Here we show that the 19 and 28 kDa bands contain VAMP/synaptobrevin-2, and rab3A/smg25A and SNAP-25, respectively. Since SPM-1 and SPM-2 recognize only syntaxins and the 28 kDa band (rab3A/smg25A and SNAP-25), respectively, the results indicate that all these proteins form a complex. Our results suggest tight linkage between the components involved in neurotransmitter release

Costa Rica Rift hole deepened and logged

During Leg 111 of the Ocean Drilling Program, scientists on the drilling vessel JOIDES Resolution studied crustal structure and hydrothermal processes in the eastern equatorial Pacific. Leg 111 spent 43 days on its primary objective, deepening and logging Hole 5048, a deep reference hole in 5.9-million-year-old crust 200 km south of the spreading axis of the Costa Rica Rift. Even before Leg 111 , Hole 5048 was the deepest hole drilled into the oceanic crust, penetrating 274.5 m of sediments and 1,075.5 m of pillow lavas and sheeted dikes to a total depth of 1,350 m below sea floor (mbsf). Leg 111 deepened the hole by 212.3 m to a total depth of 1,562.3 mbsf (1,287.8 m into basement), and completed a highly successful suite of geophysical logs and experiments, including sampling of borehole waters

Tectonic history of the Conrad Rise

第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月17日（木） 国立極地研究所　2階大会議

High-grade metamorphic rocks dredged from the Conrad Rise (research cruise KH-10-7, St. 2), the southern Indian Ocean

第2回極域科学シンポジウム/第31回極域地学シンポジウム 11月17日（木） 国立極地研究所　2階大会議

Late Proterozoic juvenile arc metatonalite and adakitic granitoids in the Sør Rondane Mountains, East Antarctica

第3回極域科学シンポジウム/第32回極域地学シンポジウム 11月30日（金） 国立極地研究所 ３階ラウン

Peak temperatures of ultra-high temperature metamorphism of the Napier Complex, Enderby Land, East Antarctica, as deduced from porphyroclastic pyroxenes of meta-ultramafic rocks

In the Mt. Riiser-Larsen area of the Archaean Napier Complex, an ultra-high temperature (UHT) metamorphic complex, Enderby Land, East Antarctica, meta-ultramafic rocks occur as blocks and pods embedded in orthopyroxene felsic gneiss or garnet felsic gneiss and as thin layers intercalated with orthopyroxene felsic gneiss. They consist mainly of olivine, orthopyroxene, clmopyroxene and spinel with or without phlogopite. On the basis of the modal proportion of olivine and pyroxene, they are classified into peridotite and minor pyroxenite. These constituent minerals are generally medium- to coarse-grained with granular texture. Furthermore, some samples also contain coarse-grained but porphyroclastic chno- and orthopyroxenes that are sometimes armored locally by neoblastic pyroxenes. Chemical compositions of granular pyroxenes are similar to those of neoblastic varieties, which are, however, different from those of porphyroclastic pyroxenes; porphyroclastic clinopyroxenes are rich in Al_2O_3 but poor in CaO as compared with granular and neoblastic clinopyroxenes. The pyroxene thermometer yields 600-650℃ for granular and neoblastic pyroxenes, while porphyroclastic pyroxenes indicate about 1130℃. The former lower temperatures are interpreted as representing a closure temperature of the thermometer, while the latter higher temperatures indicate a peak metamorphic temperature of the Napier UHT metamorphism

Chemistry of various minerals of altered basalts from ODP Hole 111-504B

Basalts recovered from Hole 504B during ODP Leg 111 are more or less altered, but there is no sign of strong shear stress or widespread penetrative deformation; hence, they retain well their primary (igneous) structures and textures. The effect of alteration is recognized as the partial or total replacement of primary minerals (olivine, clinopyroxene, and plagioclase) by secondary minerals and as the development of secondary minerals in open spaces (e.g., veins, fractures, vugs, or breccia matrix). The secondary minerals include zeolite (laumontite and stilbite), prehnite, chlorite, epidote, Plagioclase (albite and/or oligoclase), amphibole (anthophyllite, cummingtonite, actinolite, and hornblende), sodic augite, sphene, talc, anhydrite, chalcopyrite, pyrite, Fe-Ti oxide, and quartz. Selected secondary minerals from several tens of samples were analyzed by means of an electron-probe microanalyzer; the results are presented along with brief considerations of their compositional features. In terms of the model basaltic system, the following two types of low-variance (three-phase) mineral assemblages were observed: prehnite-epidote-laumontite and prehnite-actinolite-epidote; both include chlorite, albite and/or oligoclase, sphene, and quartz. The mineral parageneses delineated by these low-variance mineral assemblages suggest that the metamorphic grade ranges from the zeolite facies to the prehnite-actinolite facies. The common occurrence of prehnite indicates that greenschist facies conditions were not attained even in the deepest level of Hole 504B, which, in a strict sense, contradicts the previous interpretation that the lower portion of Hole 504B suffered greenschist facies alteration