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Eastern Edge (eastern + edge)
Selected AbstractsLate Cenozoic Geology and Paleo-environment Change in the Eastern Edge of Qinghai-Xizang PlateauACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2008ZHAO Zhizhong Abstract There are late Cenozoic lacustrine deposits and loess and red clay and moraines in eastern edge of the Qinghai-Xizang Plateau. Various genetic sediments recorded rich information on late Cenozoic paleo-environment changes. Xigeda lacustrine formed during 4.2 Ma B.P.-2.6 Ma B.P. There were 9 periodic warm-cold alternations. Eolian deposition in western Sichuan began at 1.15 Ma B.P. The loess-soil sequences recorded successively 14 paleo-monsoon climate cycles. Laterite in Chengdu plain recorded 5 stages of paleoclimatic stages since 1.13 Ma B.P. There was an old glacial period of 4.3 Ma B.P. in eastern Qinghai-Xizang Plateau. During Quaternary, there are 5 extreme paleoclimatic events corresponding with 5 glaciations. [source] Succession, palaeoecology, evolution, and speciation of Pennsylvanian non-marine bivalves, Northern Appalachian Basin, USAGEOLOGICAL JOURNAL, Issue 2 2003R. M. C. Eagar Abstract Seventeen horizons of non-marine bivalves are described within the Appalachian succession from the base of the Pottsville Group of Westphalian A-B age to the Uniontown coal of Stephanian C age at the top of the Carboniferous System. A new highly variable fauna of Anthraconaia from the roof shales of the Upper Freeport coal near Kempton, west Maryland, dates from late Westphalian D or very early Cantabrian time, on the evidence of non-marine shells and megafloras. Below this horizon, the Appalachian sequence reveals zones of Anthraconauta phillipsii and Anthraconauta tenuis in the same order as in Britain, whereas faunas of Anthraconaia of these zones are less common and differ from those of Britain. In all horizons above the Upper Freeport coal all non-marine bivalve faunas consist of stages in the sequences of two natural species, the groups of Anthraconaia prolifera and Anthraconaia puella-saravana. The first shows evidence of having lived in well-oxygenated, probably shallow, fresh water conditions of relatively wide extent. The second group lived preferentially in a plant-rich environment of relatively stagnant fresh water. Both groups are found in horizons associated with coal seams and may be seen together in the same habitats, but diagrams of variation (pictographs) suggest that there was no interbreeding between the two groups in either the Northern Appalachians or in southern Germany where the species split was first recognized. In the northern Spanish coalfields of Guardo-Valderrueda and Central Asturia, facies evidence suggests how an initial split may have taken place in the same morphological directions and into the same palaeoenvironments as the later split into two species. Appalachian deposition was generally slow and intermittent with frequent palaeosols. There is also evidence of erosion and of small palaeontological breaks in the sequence, especially near the eastern edge of the Northern Appalachian Basin in western Maryland. The amount of accumulated sediment was less than one-tenth of that of western Europe when basin centre deposition is compared. We found no evidence of a major palaeontological break representing Westphalian D strata overlain by Stephanian C strata. We figure non-marine bivalve faunas of Stephanian B age in association with the Pittsburgh and the Little Pittsburgh coals. Two new species of non-marine bivalves are described: Anthraconaia anthraconautiformis sp. nov. and Anthraconaia extrema sp. nov. Copyright © 2003 John Wiley & Sons, Ltd. [source] Japan's strategic contributions to hydro-meteorological disaster mitigation in the world: planning to establish the UNESCO,PWRI CentreHYDROLOGICAL PROCESSES, Issue 6 2006Tetsuya Ikeda Hydro-meteorological disasters such as floods are major challenges that need to be overcome in order to realize sustainable development and poverty alleviation for humankind. Devastating flood disasters have occurring in various locations throughout the world, and there has recently been rising concern that the intensity and frequency of catastrophic floods may be increasing. Being located on the eastern edge of monsoonal Asia and having climatic variations according to the seasonal and regional conditions, Japan has long suffered from numerous flood disasters, and thus has developed advanced flood management policies. This paper aims to discuss flood disasters in Japan and the recently improved flood management policies. In addition, this paper introduces a new plan attempted by the Public Works Research Institute (PWRI) of Japan that takes advantage of the wealth of long accumulated experience and knowledge in the hydro-meteorological field. The PWRI is now working toward the establishment of an International Centre on Water-related Hazard and Risk Management by acquiring UNESCO's auspices. In order to contribute to the global challenge of reducing devastating hydro-meteorological disasters all over the world, this centre aims to conduct research, capacity-building and training programmes, and information networking activities at the local, national, regional and global levels. The aim is to prevent and mitigate hydro-meteorological disasters from the viewpoint of sustainable and integrated river basin management. Copyright © 2006 John Wiley & Sons, Ltd. [source] Deep Background of Wenchuan Earthquake and the Upper Crust Structure beneath the Longmen Shan and Adjacent AreasACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2009Qiusheng LI Abstract: By analyzing the deep seismic sounding profiles across the Longmen Shan, this paper focuses on the study of the relationship between the upper crust structure of the Longmen Shan area and the Wenchuan earthquake. The Longmen Shan thrust belt marks not only the topographical change, but also the lateral velocity variation between the eastern Tibetan Plateau and the Sichuan Basin. A low-velocity layer has consistently been found in the crust beneath the eastern edge of the Tibetan Plateau, and ends beneath the western Sichuan Basin. The low-velocity layer at a depth of ,20 km beneath the eastern edge of the Tibetan Plateau has been considered as the deep condition for favoring energy accumulation that formed the great Wenchuan earthquake. [source] Late Cenozoic Geology and Paleo-environment Change in the Eastern Edge of Qinghai-Xizang PlateauACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2008ZHAO Zhizhong Abstract There are late Cenozoic lacustrine deposits and loess and red clay and moraines in eastern edge of the Qinghai-Xizang Plateau. Various genetic sediments recorded rich information on late Cenozoic paleo-environment changes. Xigeda lacustrine formed during 4.2 Ma B.P.-2.6 Ma B.P. There were 9 periodic warm-cold alternations. Eolian deposition in western Sichuan began at 1.15 Ma B.P. The loess-soil sequences recorded successively 14 paleo-monsoon climate cycles. Laterite in Chengdu plain recorded 5 stages of paleoclimatic stages since 1.13 Ma B.P. There was an old glacial period of 4.3 Ma B.P. in eastern Qinghai-Xizang Plateau. During Quaternary, there are 5 extreme paleoclimatic events corresponding with 5 glaciations. [source] Föhn as a response to changing upstream and downstream air massesTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 635 2008Georg J. Mayr Abstract Observations of föhn from the field phase of the Mesoscale Alpine Programme (MAP) are used to study how differences between the air masses upstream and downstream of the central Alpine crest determine whether the flow can descend to the lee as either shallow föhn, when it passes through passes in the mountains, or deep föhn, when it overflows the Alpine crest. First, the föhn case of 30 October 1999 is examined using ECMWF analyses and radiosonde data at various upstream and downstream locations. Additional measurements from aircraft, dropsondes, an instrumented car and automatic weather stations are then used for a detailed study of the föhn flow across the Brenner Pass. Advection of cold air around the eastern edges of the Alps and warm air around the western edge of the Alps ahead of a synoptic ridge set up a reservoir of colder air on the south side of the Alps and a reservoir of warmer air to the north. The depth to where the air was colder on the southern side was sufficient for a shallow föhn to flow through the pass. After the passage of the ridge axis, synoptic cold air advection provided another source of colder air, this time from the southwest, growing deeper with time and having a synoptically imposed cross-barrier flow component. The maximum depth to where the air upstream was colder than downstream extended just above the peaks of the highest mountains. An analysis of the detailed measurements across the Brenner Pass showed that this depth was also the top of the layer that descended and accelerated down the lee slopes of the Wipp Valley. Upstream, air above the föhn layer had an even stronger cross-barrier component yet did not descend because it did not have lower potential temperatures than the downstream side at that level. Deep föhn never developed. An examination of other well-documented MAP föhn cases confirmed the conclusion from the 30 October event that shallow and deep föhns , at least for the central Alps , are mostly a response to differences in air masses between the upstream and downstream side. A cross-barrier component of the flow was only a modification but in itself not sufficient to cause the flow to both descend and accelerate down the lee slope, unless potential temperatures on the upstream side were lower in this layer than on the downstream side. Copyright © 2008 Royal Meteorological Society [source] | ||||||||||