ASCA Observations of X-ray Emission from Ultra-luminous Infrared Galaxies     

Takao Nakagawa  Tsuneo Kii  Ryuichi Fujimoto  Toshiyuki Miyazaki  Hajime Inoue  Yasushi Ogasaka  Ryohei Kawabe 《Astrophysics and Space Science》1999,266(1-2):43-48

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Late Miocene Magmatic-Hydrothermal Systems in the Jozankei-Zenibako District, Southwest Hokkaido, Japan     

Yasushi WATANABE  Eijun OHTA 《Resource Geology》1999,49(2):59-74

Abstract: Hydrothermal systems related to magmatic intrusions in the Jozankei-Zenibako district, southwest Hokkaido are examined, based on field observations, K-Ar ages, and alteration mineral assemblages. The study reveals five major magmat–ic–hydrothermal systems of Late Miocene in age, comprising Ogawa (9. 7 Ma), Jozankei (9. 5–9. 0 Ma), Otarunaigawa (8. 7 Ma), Asarigawa (8. 8 and 6. 7 Ma) and Hariusu (6. 7 Ma). The Ogawa system is related to granodiorite, and the Jozankei, Otarunaigawa and Asarigawa systems are related to quartz porphyry.
The Ogawa system includes potassic, sericitic, propylitic and advanced argillic alteration as well as base-metal mineralization, represented by the Toyotomi deposit. The Jozankei and Otarunaigawa systems lack significant potassic alteration, and are accompanied by sericitic and propylitic alteration. The Otarunaigawa system is associated with base-metal mineralization at Toyohiro and Inatoyo. The Asarigawa and Hariusu systems include advanced argillic and argillic alteration, as well as iron sulfide deposits. The presence of potassic alteration only in the Ogawa system is ascribed to deeper emplacement (˜3 km from the surface) of the intrusive magma. These systems formed in terrestrial environments that existed from ca. 11 Ma to 8. 5 Ma and after 7. 5 Ma in the district.
Age–data compilation shows that the major advanced argillic alteration events in southwest Hokkaido, including those in the Jozankei-Zenibako district, formed during the periods from 9. 7–6. 5 Ma and 3. 5–1. 5 Ma. These periods correspond to the timing of normal subduction of the Pacific plate beneath the Northeast Japan arc. Normal, in contrast to oblique, plate subduction is characterized by andesitic, polygenetic volcanism and associated advanced argillic alteration.  相似文献   

Geology and K-Ar Ages of the South, Huh Bulgiin Hundii, Saran Uul, Taats Gol and Han Uul deposits in the Bayankhongor Region, Mongolia   总被引：2，自引：0，他引：2  

Yasushi WATANABE  Daramjav TURMAGNAI  Dolgor BYAMBASUREN  Gurjav OYUNCHIMEG  Yadamtsoo TSEDENBALJIR  Yoichi SATO 《Resource Geology》1999,49(3):123-130

Abstract: The Bayankhongor region in central Mongolia consists of a Paleozoic subduction system including Precambrian microcontinents (Baidrag and Burd Gol zones), obducted ophiolites and accretionary sedimentary rocks (Bayankhongor and Dzag zones), and forearc sedimentary rocks (Khangay zone). Arc magmatism in the Bayankhongor region is characterized by dominance of Early Paleozoic ilmenite-series and Late Paleozoic magnetite-series granitoids. These granitoids accompany many hydrothermal deposits of such various types as porphyry, skarn and vein. K-Ar dating on four deposits in the region revealed that the South porphyry Cu-Au, Huh Bulgiin Hundii skarn Cu-Au, Han Uul shear zone-hosted Au and Taats Gol pegmatite W-Au deposits formed at 240±5 Ma, 252±5 Ma, 283±6 Ma and 329±7 Ma, respectively.
Thus the former three are related to the Permian to earliest Triassic magnetite-series granitoids, whereas the W-Au pegmatite at Taats Gol to the Early Carboniferous ilmenite-series granitoids. Porphyry and skarn Cu-Au mineralization occurred at latest Permian to earliest Triassic, when the Andean-type arc magmatism was immediately followed by the collision between the Baidrag and Tarbagatai microcontinents.  相似文献   

VCS柱状采样及其在中国太湖富营养化评价中的应用     

李万春  濮培民  召古裕士 《湖泊科学》1998,10(S1):585-589

The lake sediments, especially in recent years, genuinely record human being''s activities upon the lake environment. The top 30cm sections are of significance in the process of advanced cultural eutrophication and water quality deterioration. Based on the data of 4 core sam-ples obtained in June 19-22, 1997, with VCS in northern, western and southern Taihu Lake, some preliminary results are reported. Further analyses on the physico-chemical items as well as element content may reveal more information of the accelerating cultural eutrophication.  相似文献   

Early Miocene metallogenic event formed the Bosawa low‐sulfidation epithermal gold deposit,Northeast Japan arc     

Teruhiro Suzuki  Shota Satori  Yuho Fujimaki  Yasushi Watanabe 《Resource Geology》2020,70(4):378-388

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