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Current Issue   2014 Vol.  3 No.  4 Published: 2014-10-14 Lithofacies palaeogeography and sedimentology News 1 Summary of the Editorial Committee Meeting of Journal of Palaeogeography in Geneva, at the 19th International Sedimentological Congress (ISC) The “Palaeogeography, palaeoecology and resource geology in the geological past” session was successfully held on the morning of August 19th and the afternoon of August 22nd respectively, co-chaired by Profs. Ian D. Somerville, Gérard Stampfli and Zhong-Qiang Chen. A total of 32 presentations were submitted to this session, 16 orals and 16 posters which cover the domains of: palaeobiogeography and palaeoecology, stratigraphy, sedimentology, microbialites, Geodynamics, palaeoclimatology and sedimentary responses, geochemistry and sedimentary environments. 2014 Vol. 3 (4): 1-1 [Abstract] ( 811 ) [HTML 1KB] PDF (2805 KB)   ( 212 ) Academic discussion 332 Review of research in internal-wave and internal-tide deposits of China: Discussion G. Shanmugam This discussion of a review article by Gao et al. (2013), published in the Journal of Palaeogeography (2(1): 56-65), is aimed at illustrating that interpretations of ten ancient examples in China and one in the central Appalachians (USA) as deep-water deposits of internal waves and internal tides are unsustainable. This critical assessment is based on an in-depth evaluation of oceanographic and sedimentologic data on internal waves and internal tides derived from 332 print and online published works during 1838-January 2013, which include empirical data on the physical characteristics of modern internal waves and internal tides from 51 regions of the world’s oceans (Shanmugam, 2013a). In addition, core and outcrop descriptions of deep-water strata from 35 case studies worldwide carried out by the author during 1974-2011, and a selected number of case studies published by other researchers are evaluated for identifying the sedimentological challenges associated with distinguishing types of bottom-current reworked sands in the ancient sedimentary record. The emerging conclusion is that any interpretation of ancient strata as deposits of internal waves and internal tides is premature. 2014 Vol. 3 (4): 332-350 [Abstract] ( 1620 ) [HTML 1KB] PDF (3276 KB)   ( 222 ) 351 Reply to Shanmugam, G. “Review of research in internal-wave and internal-tide deposits of China: Discussion” Zhen-Zhong Gao, You-Bin He, Xiang-Dong Li, Tai-Zhong Duan We are glad to know that our paper “Review of research in internal-wave and internal-tide deposits of China” (Gao et al., 2013) published in Journal of Palaeogeography has attracted close attention of international peers, and we noted that Shanmugam has provided a critical assessment of our paper. He claimed that “interpretations of ten ancient examples in China and one in the central Appalachians (USA) as deep-water deposits of internal waves and internal tides are unsustainable”, among many other comments and criticisms, and he concluded that “any interpretation of ancient strata as deposits of internal waves and internal tides is premature”. This article is aimed at responding to his major criticisms. We believe that constructive discussions will benefit the development of the study in internal-wave and internal-tide deposits. Unfortunately, Shanmugam seems not to follow this line of scientific criticism, but is trying to reject all research results in this subject based on his illogical and inconsistent reasoning, and distortion of others’ points of view. In this article, with facts and evidences, we will refuse the main wrong assertions of Shanmugam’s, for example, “the use of bidirectional cross-bedding as evidence for deposition by baroclinic currents in outcrop studies is sedimentologically erroneous ” and “any interpretation of ancient strata as deposits of internal waves and internal tides is premature”. We will also use typical characteristics of the ancient examples to demonstrate that they are certainly not turbidites, or contourites, or tsunami-related deposits, but internal-wave and internal-tide deposits as the most plausible to defend the rationality of our interpretation in our previous papers. 2014 Vol. 3 (4): 351-358 [Abstract] ( 1163 ) [HTML 1KB] PDF (2794 KB)   ( 196 ) Lithofacies palaeogeography and sedimentology 384 Lithofacies palaeogeography of the Late Permian Wujiaping Age in the Middle and Upper Yangtze Region, China Jin-Xiong Luo, You-Bin He, Rui Wang The lithofacies palaeogeography of the Late Permian Wujiaping Age in Middle and Upper Yangtze Region was studied based on petrography and the “single factor analysis and multifactor comprehensive mapping” method. The Upper Permian Wujiaping Stage in the Middle and Upper Yangtze Region is mainly composed of carbonate rocks and clastic rocks, with lesser amounts of siliceous rocks, pyroclastic rocks, volcanic rocks and coal. The rocks can be divided into three types, including clastic rock, clastic rock-limestone and limestone-siliceous rock, and four fundamental ecological types and four fossil assemblages are recognized in the Wujiaping Stage. Based on a petrological and palaeoecological study, six single factors were selected, namely, thickness (m), content (%) of marine rocks, content (%) of shallow water carbonate rocks, content (%) of biograins with limemud, content (%) of thin-bedded siliceous rocks and content (%) of deep water sedimentary rocks. Six single factors maps of the Wujiaping Stage and one lithofacies palaeogeography map of the Wujiaping Age were composed. Palaeogeographic units from west to east include an eroded area, an alluvial plain, a clastic rock platform, a carbonate rock platform where biocrowds developed, a slope and a basin. In addition, a clastic rock platform exists in the southeast of the study area. Hydrocarbon source rock and reservoir conditions were preliminarily analyzed based on lithofacies palaeogeography. Sedimentary environments have obvious controls over the development of the resource rocks. With regard to the abundance of organic matter, the hydrocarbon potential of the coastal swamp environment is the best, followed by the basin environment and the carbonate rock platform. The gas reservoir types of the Wujiaping Stage can be classified as conventional and unconventional gas reservoirs, like coal bed gas and shale gas; all of them have well exploration prospects. 2014 Vol. 3 (4): 384-409 [Abstract] ( 1664 ) [HTML 1KB] PDF (12740 KB)   ( 196 ) 410 Armoured mud balls as a result of ephemeral fluvial flood in a humid climate: Modern example from Guizhou Province, South China Gerhard H. Bachmann Armoured mud balls were observed after rainfall and a short flood in the otherwise dry Xiaohe (small river) valley of Guanling County, Guizhou Province, South China, app- roximately 30 km southwest of Guanling City. Armoured mud balls are most common in semi-arid climates, but rather unusual in a humid climate as in Guizhou. A number of well-rounded mud balls, 2-20 cm in diameter, were found lying on the gravel of the Xiaohe gully floor. The mud balls consist of sticky, light brown and slightly mottled clay without carbonate content. The surfaces of the mud balls were studded with rims of sand- or gravel-size limestone clasts, collected during bedload transport, as is typical for armoured mud balls. The mud balls originated from alluvial mudstone deposits of the valley floor and cliff that are most likely derived from the weathering and karstification of bedrock limestones. Such mudstones seem to be especially well suited for forming armoured mud balls. As flood events are rather common in the area, the formation of armoured mud balls should be very frequent in the Xiaohe valley and similar valleys nearby, giving the possibility for further and more detailed studies. To the best of our knowledge this is the first description of armoured mud balls in China. 2014 Vol. 3 (4): 410-418 [Abstract] ( 1310 ) [HTML 1KB] PDF (4115 KB)   ( 185 )

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