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11.
Yoshihito KAMATA 《地球学报》2009,30(Z1):19-20
In the last decade, radiolarian biostratigraphy has clarified the ages of siliceous sedimentary rocks in vari-ous parts of Thailand (e.g., Sashida et al., 1993; Ka-mata et al., 2002; Wonganan and Caridroit, 2005). These age determinations have yielded not only new litho- and chronostratigraphic interpretations, but also data on the time duration and spatial distribution of the Paleo-Tethys and its associated seaways. Recently, Kamata et al. (2009) has classify the chert into two types of “pelagic” and “hemipelagic” based on lithol-ogy, faunal content, and stratigraphy in Thailand, and presumed that the pelagic environments of the Pa-leo-Tethys would have been suitable for the deposi-tional site for the former whereas the vicinity of a continental slope and rise located in the eastern margin of the Sibumasu would have been suitable for the latter. Kamata et al., (2009) also clarified that the hemipale-gic and pelagic cherts are exposed in two north- trending zones. The western zone includes the hemipelagic chert, as well as glaciomarine and other Paleozoic to Mesozoic successions, overlying a Pre-cambrian basement of Sibumasu elements. The eastern zone contains pelagic chert and limestone and should be correlated to the Inthanon Zone (Ueno, 1999; 2002). The Inthanon zone is characterized by the presence not only of Paleo-Tethyan sedimentary rocks, but also of Sibumasu elements that structurally underlie the Pa-leo-Tethyan rocks. The boundary between the Sibu-masu and Paleo-Tethys zones is a north-trending, low-angle thrust that resulted from the collision of the Sibumasu and Indochina Blocks (Ueno, 2002; Kamata et al., 2009) 相似文献
12.
Hidetoshi Hara Koji Wakita Katsumi Ueno Yoshihito Kamata Ken-ichiro Hisada Punya Charusiri Thasinee Charoentitirat Pol Chaodumrong 《Gondwana Research》2009,16(2):310
We reconstructed the accretion process related to Paleo-Tethys subduction recorded in northern Thailand, based on mélange and thrust structures, and metamorphic temperatures derived from illite crystallinity data. Mélange formation was characterized by hydrofracturing and cataclastic deformation, with mud injection under semi-lithified conditions followed by shear deformation and pressure solution. Illite crystallinity data suggest metamorphic temperatures below 250 °C during mélange formation. The combined structural and metamorphic data indicate that during mélange formation, the accretionary complex related to Paleo-Tethys subduction developed at shallow levels within an accretionary prism. Asymmetric shear fabrics in mélange indicate top-to-south shear. After correction for rotation associated with collision between the Indian and Eurasian continents, the trend of the Paleo-Tethys subduction zone is estimated to have been N80 °E. We conclude that the Paleo-Tethys was subducted northward beneath the Indochina Block from the Permian to Triassic. 相似文献
13.
Hidetoshi HARA Miyuki KUNII Ken-ichiro HISADA Katsumi UENO Yoshihito KAMATA Punya CHARUSIRI Thasinee CHAROENTITIRAT 《地球学报》2012,33(S1):15-15
The accretionary complex related to the Pa-leo-Tethys subduction was developed along western margin of the Indochina Block in northern Thailand. The provenance, source rock compositions, and sedi-ment supply system of the accretionary complex were reconstructed based on the petrography and geochem-istry of clastic rocks, U-Pb dating of detrital zircons. 相似文献
14.
Zagros orogen extends from the Turkish-Iranian border to NW,to the Makran area in SE.According to Geological Survey of Iran 100,000 series "Sureyan", "Saadatshahr","Abadeh-E-Tashk" and "Arsenjan",the Zagros orogen comprises the following sub-parallel tectonostratigraphic domains,from SW to NE:the 相似文献
15.
Yoshihito Kamata Katsumi Ueno Hidetoshi Hara Megumi Ichise Thasinee Charoentitirat Punya Charusiri Apsorn Sardsud Ken-ichiro Hisada 《Island Arc》2009,18(1):21-31
Two types of chert are defined in Thailand based on lithology, faunal content, and stratigraphy. 'Pelagic chert' consists of densely packed radiolarian tests in a microcrystalline quartz matrix with no terrigenous material and is found as blocks embedded within sheared matrix. 'Hemipelagic chert' also has a microcrystalline quartz matrix, and contains not only scattered radiolarian tests, but also calcareous organisms such as foraminifers. The pelagic cherts range in age from Devonian to Middle Triassic, whereas hemipelagic chert is only from the Early to the Late Triassic. Lithological and stratigraphic characteristics indicate that the pelagic chert originated in the Paleo-Tethys, whereas the hemipelagic chert accumulated on the eastern margin of the Sibumasu Block. The hemipelagic and pelagic chert are exposed in two north-trending belt-like zones. The western zone includes the hemipelagic chert, as well as glaciomarine and other Paleozoic to Mesozoic successions, overlying a Precambrian basement that consists exclusively of Sibumasu elements. The eastern zone contains pelagic chert and limestone and should be correlated to the Inthanon Zone. The Inthanon Zone is characterized by the presence not only of Paleo-Tethyan sedimentary rocks, but also of Sibumasu Block elements that structurally underlie the Paleo-Tethyan rocks. The boundary between the Sibumasu and Paleo-Tethys zones is a north-trending, low-angle thrust that resulted from the collision of the Sibumasu and Indochina blocks. 相似文献
16.
Nobutaka Shimada Tomoki Nakamura Yasuo Morinaga Yoshihito Shikama 《Resource Geology》2005,55(2):91-100
Abstract. The presence of invisible gold was confirmed in arsenian pyrite from the Hishikari epithermal gold deposit, Kagoshima, Japan, by means of EPMA and SIMS analyses. The relative concentration of invisible gold may be positively correlated with As contents (0.01 to 10.37 wt%) of fine-grained arsenian pyrite which commonly occurs in the auriferous quartz veins. Although arsenian pyrite occurs widely in any mineralization stage with electrum and other sulfide, sulfosalts, selenide or telluride minerals, arsenian pyrites having higher As contents accompanied by invisible gold occur dominantly in the middle stage of fine-adularia-quartz and in the late stage of coarse-quartz rather than in the early stage of columnar-adularia. 相似文献