Paleogeographic maps of the Japanese Islands: Plate tectonic synthesis from 750 Ma to the present   总被引：73，自引：1，他引：73  

Shigenori  Maruyama  Yukio  Isozaki  Gaku  Kimura Masaru  Terabayashi 《Island Arc》1997,6(1):121-142

Abstract A series of paleogeographic maps of the Japanese Islands, from their birth at ca 750–700 Ma to the present, is newly compiled from the viewpoint of plate tectonics. This series consists of 20 maps that cover all of the major events in the geotectonic evolution of Japan. These include the birth of Japan at the rifted continental margin of the Yangtze craton ( ca 750-700 Ma), the tectonic inversion of the continental margin from passive to active ( ca 500 Ma), the Paleozoic accretionary growth incorporating fragments from seamounts and oceanic plateaux ( ca 480-250 Ma), the collision between Sino-Korea and Yangtze (250–210 Ma), the Mesozoic to Cenozoic accretionary growth (210 Ma-present) including the formation of the Cretaceous paired metamorphic belts (90 Ma), and the Miocene back-arc opening of the Japan Sea that separated Japan as an island arc (25-15 Ma).  相似文献   

Experimental and theoretical study of stability of dense hydrous magnesium silicates in the deep upper mantle     

Tetsuya Komabayashi  Soichi Omori  Shigenori Maruyama 《Physics of the Earth and Planetary Interiors》2005,153(4):191-209

Fluid-undersaturated experiments were conducted to determine the phase relations in the simplified peridotite system MgO-SiO₂-H₂O (MSH) at 11.0-14.5 GPa and 800-1400 °C. Stability relations of dense hydrous magnesium silicates (DHMSs) under fluid-undersaturated conditions were experimentally examined. From the fluid-absent experimental results, we retrieved thermodynamic data for clinohumite, phase A, phase E, and hydrous wadsleyite, consistent with the published data set for dry mantle minerals. With this new data set, we have calculated phase equilibria in the MSH system including dehydration reactions. The dehydration reactions calculated with lower water activities of 0.68-0.60 match the fluid-present experiments of this study above 11.0 GPa and 1000 °C, indicating that considerable amounts of silicate component were dissolved into the fluid phase. The calculated phase equilibria illustrate the stability of the post-antigorite phase A-bearing assemblages. In the cold subducting slab peridotite, phase A + enstatite assemblage survives into the transition zone, whereas phase A + forsterite + enstatite assemblage forms hydrous wadsleyite at a much shallower depth of about 360-km. The slab is subducted with no dehydration reactions occurring when entering the transition zone. The phase equilibria also show the high temperature stability of phase E. Phase E is stable up to 1200 °C at 13.5 GPa, a plausible condition in the mantle of relatively low temperature, i.e., beneath subduction zones. Phase E is a possible water reservoir in the mantle as well as wadsleyite and ringwoodite.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987114000917     

Miyuki Tahata  Yusuke Sawaki  Yuichiro Ueno  Manabu Nishizawa  Naohiro Yoshida  Toshikazu Ebisuzaki  Tsuyoshi Komiya  Shigenori Maruyama 《地学前缘(英文版)》2015,6(1):121-136

Important ecological changes of the Earth(oxidization of the atmosphere and the ocean) increase in nutrient supply due to the break-up of the super continent(Rodinia) and the appearance of multi-cellular organisms(macroscopic algae and metazoan) took place in the Ediacaran period,priming the Cambrian explosion.The strong perturbations in carbon cycles in the ocean are recorded as excursions in carbonate and organic carbon isotope ratio(δ~(13)C_(carb) and δ~(13)C_(org)) from the Ediacaran through early Cambrian periods.The Ediacaran-early Cambrian sediment records of δ~(13)C_(carb) and δ~(13)C_(org),obtained from the drill-core samples in Three Gorges in South China,are compared with the results of numerical simulation of a simple one-zone model of the carbon cycle of the ocean,which has two reservoirs(i.e.,dissolved organic carbon(DOC) and dissolved inorganic carbon(DIC).The fluxes from the reservoirs are assumed to be proportional to the mass of the carbon reservoirs.We constructed a model,referred to here as the Best Fit Model(BFM),which reproduce δ~(13)C_(carb) and δ~(13)C_(org) records in the Ediacaran-early Cambrian period noted above.BFM reveals that the Shuram excursion is related to three major changes in the carbon cycle or the global ecological system of the Earth:(1) an increase in the coefficient of remineralization by a factor of ca.100,possibly corresponding to a change in the dominant metabolism from anaerobic respiration to aerobic respiration,(2) an increase of carbon fractionation index from 25‰ to 33‰,possibly corresponding to the change in the primary producer from rock-living cyanobacteria to free-living macro algae,and(3) an increase in the coefficient of the organic carbon burial by a factor of ca.100,possibly corresponding to the onset of a biological pump driven by the flourishing metazoan and zooplankton.The former two changes took place at the start of the Shuram excursion,while the third occurred at the end of the Shuram excursion.The other two excursions are explained by the tentative decrease in primary production due to cold periods,which correspond to the Gaskiers(ca.580 Ma) and Bikonor(ca.542 Ma) glaciations.  相似文献   

Tectonic evolution of the ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic belts from central China   总被引：28，自引：0，他引：28  

Shigenori  Maruyama  J. G. Liou  Ruyuan  Zhang 《Island Arc》1994,3(2):112-121

Abstract In the Triassic suture between the Sino-Korean and Yangtze cratons, the Dabie metamorphic Complex in central China includes three tectonic units: the northern Dabie migmatitic terrane, the central ultrahigh-P coesite- and diamond-bearing eclogite belt, and the southern high-P blueschist-eclogite belt. This complex is bounded to the north by a north-dipping normal fault with a Paleozoic accretionary complex and to the south by a north-dipping reverse fault with Yangtze basement plus its foreland fold-and-thrust sequence. Great differences in metamorphic pressure suggests that these units reached different depths during metamorphism and their juxtaposition occurred by wedge extrusion of subducted old continental fragments. These units were subsequently subjected to (i) Barrovian type regional metamorphism and deformation at shallow depths; (ii) intrusion of Cretaceous granitic plutons; and (iii) doming and segmentation into several blocks by normal and strike-slip faults. A new speculative model of tectonic exhumation of UHP rocks is proposed.  相似文献   

On-going orogeny in the outer-arc of the Timor–Tanimbar region, eastern Indonesia     

Yoshiyuki Kaneko  Shigenori Maruyama  Ade Kadarusman  Tsutomu Ota  Masahiro Ishikawa  Tatsuki Tsujimori  Akira Ishikawa  Kazuaki Okamoto   《Gondwana Research》2007,11(1-2):218

The Timor–Tanimbar islands of eastern Indonesia form a non-volcanic arc in front of a 7 km deep fore-arc basin that separates it from a volcanic inner arc. The Timor–Tanimbar Islands expose one of the youngest high P/T metamorphic belts in the world, providing us with an excellent opportunity to study the inception of orogenic processes, undisturbed by later tectonic events.Structural and petrological studies of the high P/T metamorphic belt show that both deformation and metamorphic grade increase towards the centre of the 1 km thick crystalline belt. Kinematic indicators exhibit top-to-the-north sense of shear along the subhorizontal upper boundaries and top-to-the-south sense in the bottom boundaries of the high P/T metamorphic belt. Overall configuration suggests that the high P/T metamorphic rocks extruded as a thin sheet into a space between overlying ophiolites and underlying continental shelf sediments. Petrological study further illustrates that the central crystalline unit underwent a Barrovian-type overprint of the original high P/T metamorphic assemblages during wedge extrusion, and the metamorphic grade ranged from pumpellyite-actinolite to upper amphibolite facies.Quaternary uplift, marked by elevation of recent reefs, was estimated to be about 1260 m in Timor in the west and decreases toward Tanimbar in the east. In contrast, radiometric ages for the high P/T metamorphic rocks suggest that the exhumation of the high P/T metamorphic belt started in western Timor in Late Miocene time and migrated toward the east. Thus, the tectonic evolution of this region is diachronous and youngs to the east. We conclude that the deep-seated high P/T metamorphic belt extrudes into shallow crustal levels as a first step, followed by doming at a later stage. The so-called ‘mountain building’ process is restricted to the second stage. We attribute this Quaternary rapid uplift to rebound of the subducting Australian continental crust beneath Timor after it achieved positive buoyancy, due to break-off of the oceanic slab fringing the continental crust. In contrast, Tanimbar in the east has not yet been affected by later doming. A wide spectrum of processes, starting from extrusion of the high P/T metamorphic rocks and ending with the later doming due to slab break-off, can be observed in the Timor–Tanimbar region.  相似文献   

Methane-induced dolomite “chimneys” on the Kuroshima Knoll, Ryukyu islands, Japan     

Rika Takeuchi  Ryo Matsumoto  Shigenori Ogihara  Hideaki Machiyama 《Journal of Geochemical Exploration》2007,95(1-3):16

The Kuroshima Knoll is about 26 km south of Ishigaki Island in the southern part of the Ryukyu Arc. The area is considered to be the source area of “The 1771 Yaeyama Earthquake Tsunami”, which was due to the submarine landslide caused by an earthquake. It has been cleared from some investigations using “Dolphin 3K” and “Shinkai 2000” that there are large-scale dead Calyptogena colonies, many gravels of fallen dolomite chimneys and carbonates on the top of the Knoll [Matsumoto, T., Uechi, C., Kimura, M., 1997; Machiyama, H., Matsumoto, T., Matsumoto, R., Hattori, M., Okano, M., Iwase, R., Tomaru, H., 2001b.]. Carbonates of Kuroshima Knoll have various shapes and macroscopic textures. These have been classified into 4 types; shell crust (pavement), chimney, burrow, and nodule. It is clear that all chimney and burrow carbonates are composed of dolomite, while shell curst and nodule are composed of calcite, sometimes both calcite and dolomite. These carbonates are considered to have been formed by cold seep, because they are characterized by the light carbon isotopic ratio (semi-biogenic) and the heavy oxygen isotopic ratio. This suggests that methane hydrate layers develop under this survey area and the water that has the heavy oxygen and the light carbon isotopic ratio is derived from the dissociation of methane hydrate.  相似文献   

Paleozoic submarine volcanoes in the high-P/T metamorphosed Chichibu system of Eastern Shikoku, Japan     

Shigenori Maruyama  Masao Yamasaki   《Journal of Volcanology and Geothermal Research》1978,4(1-2)

The Sawadani greenstone in the Chichibu Paleozoic System is an ancient submarine volcanic complex consisting of pillow lavas and hyaloclastites. The volcanism is divided into two periods. Alkali basalt was erupted in the first period and two shield-shaped cones were formed. After a period of dormancy the volcanism of the second period took place and a cone was formed by eruptions of lavas ranging in composition from mildly alkaline to tholeiitic basalt. The top of the volcano nearly reached the sea surface and was finally about 3.7 km above the base. A limestone cap and volcanic conglomerate were deposited on the summit. The base rests conformably on upper Carboniferous sandstone and subordinate mudstone derived from a continent or mature island arc. Many feeding channels of lava cut the volcanic body and underlying sedimentary formation. Sedimentation proceeded concurrently on the surrounding sea floor, so that volcanic and sedimentary material is interlayered.The Sawadani greenstone, although it occurs in the high-P/T metamorphic belt, is not believed to be a fragment of oceanic crust (ophiolite complex) formed by oceanic ridge volcanism and later carried into a convergent zone. It is a seamount formed on and within a sedimentary sequence near a continent or island arc. The magma changed from alkaline to tholeittic as the volcano grew.It cannot be assumed that all metavolcanic rocks formed in high-pressure metamorphic terranes are fragments of oceanic crust.  相似文献   

Experimental study on the deterioration and natural remediation of the Ariake Sea tidal mud caused by the sea laver treatment acid practice and the upward seepage of pore water liquid     

Yan-Jun Du  Song-Yu Liu  Shigenori Hayashi 《Environmental Geology》2008,55(4):889-900

This study presents a laboratory study of the following two aspects: (1) the influence of sea laver treatment acid on the geoenvironmental properties of Ariake Sea tidal mud, and (2) the natural remediation effect on the sea laver treatment acid contaminated Ariake Sea tidal mud caused by the upward seepage of pore water liquid in the mud. Firstly, the mechanisms of the transport of sea laver treatment acid in the Ariake Sea tidal mud and the generation mechanisms of the upward seepage flow in the Ariake Sea tidal mud are discussed. Secondly, a series of one-dimensional laboratory infiltration tests were carried out to investigate the deterioration of the Ariake Sea tidal mud caused by the sea laver acid treatment practice. Test results reveal that the acid treatment practice caused considerable change in the geochemical properties of the mud in terms of increase in sulfide content and decrease in pH value. After the treatment by the sea laver treatment acid, the sulfide content of the mud even exceeded the safe limit value for the benthos, which represents undesirable living condition for benthos. Thirdly, series of laboratory fresh seawater infiltration tests for the deteriorated Iida site mud were conducted to illustrate this natural remediation efficiency. It is found that with the infiltration of the fresh seawater, the sulfide content of the Iida site mud was considerably reduced and pH value increased to an acceptable range for benthos living in the tidal flat mud. With the increase in the infiltration time and the hydraulic gradient, the remediation efficiency could be increased.  相似文献   

Determination of Sr/Sr mass-dependent isotopic fractionation and radiogenic isotope variation of Sr/Sr in the Neoproterozoic Doushantuo Formation     

Takeshi Ohno  Tsuyoshi Komiya  Yuichiro Ueno  Takafumi Hirata  Shigenori Maruyama 《Gondwana Research》2008,14(1-2):126

We measured both mass-dependent isotope fractionation of δ⁸⁸Sr (⁸⁸Sr/⁸⁶Sr) and radiogenic isotopic variation of Sr (⁸⁷Sr/⁸⁶Sr) for the Neoproterozoic Doushantuo Formation that deposited as a cap carbonate immediately above the Marinoan-related Nantuo Tillite. The δ⁸⁸Sr and ⁸⁷Sr/⁸⁶Sr compositions showed three remarkable characteristics: (1) high radiogenic ⁸⁷Sr/⁸⁶Sr values and gradual decrease in the ⁸⁷Sr/⁸⁶Sr ratios, (2) anomalously low δ⁸⁸Sr values at the lower part cap carbonate, and (3) a clear correlation between ⁸⁷Sr/⁸⁶Sr and δ⁸⁸Sr values. These isotopic signatures can be explained by assuming an extreme greenhouse condition after the Marinoan glaciation. Surface seawater, mixed with a large amount of freshwater from continental crusts with high ⁸⁷Sr/⁸⁶Sr and lighter δ⁸⁸Sr ratios, was formed during the extreme global warming after the glacial event. High atmospheric CO₂ content caused sudden precipitation of cap carbonate from the surface seawater with high ⁸⁷Sr/⁸⁶Sr and lighter δ⁸⁸Sr ratios. Subsequently, the mixing of the underlying seawater, with unradiogenic Sr isotope compositions and normal δ⁸⁸Sr ratios, probably caused gradual decrease of the ⁸⁷Sr/⁸⁶Sr ratios of the seawater and deposition of carbonate with normal δ⁸⁸Sr ratios. The combination of ⁸⁷Sr/⁸⁶Sr and δ⁸⁸Sr isotope systematics gives us new insights on the surface evolution after the Snowball Earth.  相似文献   

Modification of the High-Pressure-Type Chromites into the Low- Pressure-Type: Petrological Investigation of the Podiform Chromitites in the Luobusa Ophiolite, Tibet     

YAMAMOTO Shinji  KOMIYA Tsuyoshi  MARUYAMA Shigenori 《《地质学报》英文版》2015,89(Z2):104-104

<正>The podiform chromitites in the Luobusa ophiolite,Southern Tibet,have received much attention because of the presence of ultrahigh-pressure minerals,such as microdiamonds(Bai et al.,1993;Yang et al.,2007;Xu et al.,2009),coesite(Yang et al.,2007)and highly reduced metal phases(Bai et al.,2000;Robinson et al.,2004).The  相似文献