Geological Traverse from Yangtze Craton to the North China Craton Through Qinling-Dabie Mobile Belt, Central China: a Post-Symposium Field Trip of IGCP-368/411/440 in 1999     

S. Sengupta  M. Yoshida  X. Wang 《Gondwana Research》2000,3(4):566-569

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A Report of the Post-Conference Field Trip in the Eastern Arunta Inlier, Central Australia     

Kaushik Das  M. Yoshida 《Gondwana Research》2000,3(2):271

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Gas seepage from Tokamachi mud volcanoes, onshore Niigata Basin (Japan): Origin, post-genetic alterations and CH₄-CO₂ fluxes     

G. Etiope  R. NakadaK. Tanaka  N. Yoshida 《Applied Geochemistry》2011,26(3):348-359

Methane and CO₂ emissions from the two most active mud volcanoes in central Japan, Murono and Kamou (Tokamachi City, Niigata Basin), were measured in from both craters or vents (macro-seepage) and invisible exhalation from the soil (mini- and microseepage). Molecular and isotopic compositions of the released gases were also determined. Gas is thermogenic (δ¹³C_CH4 from −32.9‰ to −36.2‰), likely associated with oil, and enrichments of ¹³C in CO₂ (δ¹³C_CO2 up to +28.3‰) and propane (δ¹³C_C3H8 up to −8.6‰) suggest subsurface petroleum biodegradation. Gas source and post-genetic alteration processes did not change from 2004 to 2010. Methane flux ranged within the orders of magnitude of 10¹-10⁴ g m⁻² d⁻¹ in macro-seeps, and up to 446 g m⁻² d⁻¹ from diffuse seepage. Positive CH₄ fluxes from dry soil were widespread throughout the investigated areas. Total CH₄ emission from Murono and Kamou were estimated to be at least 20 and 3.7 ton a⁻¹, respectively, of which more than half was from invisible seepage surrounding the mud volcano vents. At the macro-seeps, CO₂ fluxes were directly proportional to CH₄ fluxes, and the volumetric ratios between CH₄ flux and CO₂ flux were similar to the compositional CH₄/CO₂ volume ratio. Macro-seep flux data, in addition to those of other 13 mud volcanoes, supported the hypothesis that molecular fractionation (increase of the “Bernard ratio” C₁/(C₂ + C₃)) is inversely proportional to gas migration fluxes. The CH₄ “emission factor” (total measured output divided by investigated seepage area) was similar to that derived in other mud volcanoes of the same size and activity. The updated global “emission-factor” data-set, now including 27 mud volcanoes from different countries, suggests that previous estimates of global CH₄ emission from mud volcanoes may be significantly underestimated.  相似文献   

Analysis of formation pressure test results in the Mount Elbert methane hydrate reservoir through numerical simulation     

Masanori Kurihara  Akihiko SatoKunihiro Funatsu  Hisanao OuchiYoshihiro Masuda  Hideo NaritaTimothy S. Collett 《Marine and Petroleum Geology》2011,28(2):502-516

Targeting the methane hydrate (MH) bearing units C and D at the Mount Elbert prospect on the Alaska North Slope, four MDT (Modular Dynamic Formation Tester) tests were conducted in February 2007. The C2 MDT test was selected for history matching simulation in the MH Simulator Code Comparison Study. Through history matching simulation, the physical and chemical properties of the unit C were adjusted, which suggested the most likely reservoir properties of this unit. Based on these properties thus tuned, the numerical models replicating “Mount Elbert C2 zone like reservoir”, “PBU L-Pad like reservoir” and “PBU L-Pad down dip like reservoir” were constructed. The long term production performances of wells in these reservoirs were then forecasted assuming the MH dissociation and production by the methods of depressurization, combination of depressurization and wellbore heating, and hot water huff and puff. The predicted cumulative gas production ranges from 2.16 × 10⁶ m³/well to 8.22 × 10⁸ m³/well depending mainly on the initial temperature of the reservoir and on the production method.This paper describes the details of modeling and history matching simulation. This paper also presents the results of the examinations on the effects of reservoir properties on MH dissociation and production performances under the application of the depressurization and thermal methods.  相似文献   

Carbon and oxygen isotope chemostratigraphies of the Yangtze platform,South China: Decoding temperature and environmental changes through the Ediacaran     

Miyuki Tahata  Yuichiro Ueno  Tomoko Ishikawa  Yusuke Sawaki  Kazuki Murakami  Jian Han  Degan Shu  Yong Li  Junfeng Guo  Naohiro Yoshida  Tsuyoshi Komiya 《Gondwana Research》2013,23(1):333-353

Multicellular animals first appeared on the earth during the Ediacaran period. However, the relationship between the abrupt biological evolution and environmental changes is still ambiguous. In order to examine seawater temperature and the carbon cycle through the Ediacaran, we analyzed the carbon and oxygen isotope compositions of carbonate rocks from drill cores from the Three Gorges area, South China. Importantly, the core samples include the Nantuo tillite, corresponding to the Marinoan glaciation, through the Doushantuo to the lower Dengying Fms. in ascending order.The δ¹³C profile displays five positive and five negative anomalies (PI-1 to 5 and NI-1 to 5), and the oxygen isotopes display very high absolute values around 0‰ with the highest at + 1.83‰. The combined δ¹⁸O and δ¹³C chemostratigraphies display both positive and negative correlations between the δ¹⁸O and δ¹³C values. The occurrence of the negative correlations supports the preservation of primary δ¹⁸O and δ¹³C values.The sample NI-4 has a negative correlation of the δ¹⁸O and δ¹³C excursions. The correlation supports a primary signature for both δ¹⁸O and δ¹³C variations. The positive δ¹⁸O excursion, accompanied by evidence of a eustatic sea-level fall, provides direct evidence for global cooling in the mid-Ediacaran; the 580 Ma Gaskiers Glaciation is a potential candidate for this global cooling event. The negative δ¹³C excursion was possibly caused by an increase in remineralization of dissolved organic carbon (DOC) due to enhanced continental weathering during the glaciation.Sample NI-5 is characterized by very low δ¹³C values, down to ? 10‰, corresponding to the Shuram-Wonoka-Pertatataka Excursion. The cause of the δ¹³C negative excursion is still not clear. However, a ubiquitous occurrence in excursions worldwide, and the lower δ¹³C values in deeper sections favor the enhancement of remineralization and respiration rather than secondary alteration, a restricted sea environment and lithification in coastal areas.  相似文献   

Activity of IGCP-368 During 2000     

M. Yoshida  M. Santosh  C.B. Dissanayake 《Gondwana Research》2001,4(2):249

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Tectonics and Mineralization in the Arabian Shield and its Extensions: Introduction     

Rao S. Divi  Masaru Yoshida 《Gondwana Research》2001,4(2):129

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Recent Advances in the Study of Gondwana Crustal Fragments     

M. Santosh  M. Yoshida  C.B. Dissanayake 《Gondwana Research》2001,4(2):231

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Prediction of ground motion in the Osaka sedimentary basin associated with the hypothetical Nankai earthquake     

Haruko Sekiguchi  Masayuki Yoshimi  Haruo Horikawa  Kunikazu Yoshida  Sunao Kunimatsu  Kenji Satake 《Journal of Seismology》2008,12(2):185-195

We studied the long-period ground motions in the Osaka sedimentary basin, Japan, which contains a 1- to 3-km thickness of sediments and is the site of many buildings or construction structures with long-natural period. We simulated the broadband ground motions likely to be produced by the hypothetical Nankai earthquake: the earthquake expected to give rise to the most severe long-period ground motion within the basin. For the simulation, we constructed multiscale heterogeneous source models based on the Central Disaster Management Council of Japan (CDMC) source model and adopted a hybrid computation method in which long-period motion and short-period motion are computed using a 3-D finite difference method and the stochastic Green’s function method, respectively. In computing long-period motions, we used a 3-D structure model of the crust and the Osaka sedimentary basin. The ground motions are estimated to have peak velocities of 50–90 cm/s, prolonged durations exceeding 300 s, and long predominant periods of 5–10 s in the area with great thickness of sediments. The predominant periods are in agreement with an approximate evaluation by 4 H/V _s where H and V _s are the thickness of the sediment and the average S wave velocity, respectively.  相似文献   

IGCP-368: Activities and Future Programmes     

M. Yoshida  M. Santosh  C.B. Dissanayake 《Gondwana Research》1999,2(4):667-669

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