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1.
Recent Progress on Global Change Research in China 总被引：2，自引：0，他引：2
ＲＥＣＥＮＴＰＲＯＧＲＥＳＳＯＮＧＬＯＢＡＬＣＨＡＮＧＥＲＥＳＥＡＲＣＨＩＮＣＨＩＮＡＦｕＣｏｎｇｂｉｎ，ＹｅＤｕｚｈｅｎｇ（ＣｈｉｎａＣｏｍｍｉｔｔｅｅｆｏｒＩＧＢＰ，ＣＡＳＴ，Ｂｅｉｊｉｎｇ１００００８）ＲＥＣＥＮＴＰＲＯＧＲＥＳＳＯＮＧＬＯＢＡ... 相似文献
2.
southChinaisoneofWellknownregionSwitheddeVelops~~inthe~es~intheGulzhouandG~provinCeSwherethe~manhashowellstudiedwithgreatachie~,whichhave~a~a~nfromthe~iSbothatdomticandabroad.SinCelabac~hasbornethe.hotPOint"forthemeearchofoutcrops~stratigraphyinClam,andconS~yyieldssomehigh--qualitypapeds(Muetal.,1992;XuandMa1992;Xuetal.,1993;DUetal.,1994;DUandYak1994;Gongatal.,1994;Wuetal.,1994;ChenandChen,1994a,b).Onthebasisofco~noftheDevonhasequenceinGultheuandG~,SouthernQinlingandho~han.thispape… 相似文献
3.
Devonian Sea-Level Change Rhythms in South China and Coupling Relationships Among the Earth-spheres 总被引：5，自引：0，他引：5
Gong Yiming Faculty of Earth Science China University of Geosciences Wuhan Hubei Wu Yi Guangxi Institute of Geology Nanning GuangxiDu Yuansheng Feng Qinglai Liu BenpeiChina University of Geosciences Wuhan Hubei 《《地质学报》英文版》1997,71(4):370-385
Twenty orthosequences and their corresponding sea-level change (SLC) cycles have been recognized in the Devonian overlying the Caledonian unconformity, of which 9, 5.5 and 5.5 occurred in the Lower, Middle and Upper Devonian respectively. They can be grouped into 4 orthosequence sets, in which the maximum flooding surfaces lie in the sulcutus Zone (D12), perbonus Zone (D13), Middle and Upper varcus Zone (D22) and gigas Zone (D21) respectively. Four instant palaeogeographical reconstructions of South China have been made in the Emsian and Givetian. Devonian sea-level change rhythms of South China can be divided into 3 categories: the autorhythmic, the worldwide and regional allorhythmic, and the coupling-rhythmic. They developed respectively in the Famennian, Pragian, Eifelian, Lochkovian, Emsian, Givetian, Frasnian and the F / F (between the Frasnian and Famennian) event. The cause of the worldwide allorhythmic SLC of the Pragian and Eifelian under comparatively dry, warm and tranquil conditions may be 相似文献
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Doklady Earth Sciences - An attempt to provide a new explanation for the change in the geodynamic regime in the Early Cretaceous is presented below. It accounts for data on a number of global... 相似文献
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INTRODUCTIONAfteralongperiodofevollltionfromepicontinentalseaviariftbasinandintercontinentalseatoanoceanicbasinduringMesozoic,theeastalsNeO--tetherchangedagainideanepicontinentalseainthelateStCretaCeous.Atca80Ma,thenorthwarddriftingoftheindianplatefindlyleadtothecontaCtandinitialcollisionoftheplatewiththeEUrasiancontinent,resultinginalargeamplitudeofsealevelfallandtheconsequentlowersealevelperiodinnorthernHimalayas(Shietal.,1995).DUringPalcogene,theseaareaswererestrictedinspacelargel… 相似文献
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Thi Phuong Quynh Le Nhu Da Le Viet Nga Dao Emma Rochelle-Newall Thi Mai Huong Nguyen Cyril Marchand Thi Thuy Duong Thi Xuan Binh Phung 《Environmental Earth Sciences》2018,77(18):658
Global riverine carbon concentrations and fluxes have been impacted by climate and human-induced changes for many decades. This paper aims to reconstruct the longterm carbon concentrations and carbon fluxes of the Red River, a system under the coupled pressures of environmental change and human activity. Based on (1) the relationships between particulate and dissolved organic carbon (POC, DOC) or dissolved inorganic carbon (DIC), and suspended sediments (TSS) or river water discharge and on (2) the available detailed historical records of river discharge and TSS concentration, the variations of the Red River carbon concentration and flux were estimated for the period 1960–2015. The results show that total carbon flux of the Red River averaged 2555?±?639 kton C year?1. DIC fluxes dominated total carbon fluxes, representing 64% of total, reflecting a strong weathering process from carbonate rocks in the upstream basin. Total carbon fluxes significantly decreased from 2816 kton C year?1 during the 1960s to 1372 kton C year?1 during the 2010s and showed clear seasonal and spatial variations. Organic carbon flux decreased in both quantity and proportion of the total carbon flux from 40.9% in 1960s to 14.9% in 2010s, reflecting the important impact of dam impoundment. DIC flux was also reduced over this period potentially as a consequence of carbonate precipitation in the irrigated, agricultural land and the reduction of the Red River water discharge toward the sea. These decreases in TSS and carbon fluxes are probably partially responsible for different negatives impacts observed in the coastal zone. 相似文献
9.
Saline Lakes’ Response to Global Change 总被引：1，自引：0，他引：1
Abraham Lerman 《Aquatic Geochemistry》2009,15(1-2):1-5
10.
《Geoforum》2015
This paper suggests that a constant exposure to and experience of socio-historical and economic changes throughout young people’s formative years assist in development of individualisation and human agency capabilities, which impact on motivations for migration.Focusing on the cohort of Polish graduates, born in the late 1970s and early 1980s, who migrated to England post-2004, the paper highlights a relationship of individuals with change. It argues that frequent and major changes shaped such generational units into highly responsive, easily adjustable and focused on capitalising upon further relationship with change, e.g. through migration.The paper distinguishes two generational units within the researched cohort: ‘Generation of Change’ and ‘European Generation of Opportunities and Migration’. It also highlights that one of the motivations for migration of both groups is practical consciousness (Giddens, 1984) inaccessible to mindful reflection in migration motivations to England.Correspondingly, the paper contends that a generational belonging encompasses both the intentional and non-discursive agency in migratory contexts. Therefore, it is significant to explore and understand individuals’ generational vantage view of the world. 相似文献
11.
In this article, Milkov and Sassen’s model is selected to calculate the thickness of the gas hydrate stable zone (GHSZ) and the amount of gas hydrate in the Xisha (西沙) Trough at present and at the last glacial maximum (LGM), respectively, and the effects of the changes in the bottom water temperature and the sea level on these were also discussed. The average thickness of the GHSZ in Xisha Trough is estimated to be 287 m and 299 m based on the relationship between the GHSZ thickness and the water depth established in this study at present and at LGM, respectively. Then, by assuming that the distributed area of gas hydrates is 8 000 km2 and that the gas hydrate saturation is 1.2% of the sediment volume, the amounts of gas hydrate are estimated to be ~2.76×1010 m3 and ~2.87×1010 m3, and the volumes of hydrate-bound gases are ~4.52×1012 m3 and ~4.71×1012 m3 at present and at LGM, re- spectively. The above results show that the thickness of GHSZ decreases with the bottom water tem- perature increase and increases with the sea level increase, wherein the effect of the former is larger than that of the latter, that the average thickness of GHSZ in Xisha Trough had been reduced by ~12 m, and that 1.9×1011 m3 of methane is released from approximately 1.1×109 m3 of gas hydrate since LGM. The released methane should have greatly affected the environment. 相似文献
12.
Research on abrupt paleoclimatic and paleoenvironmental change provides a scientific basis for evaluating future climate. Because of spatial variability in monsoonal rainfall, our knowledge about climate change during the mid-to lateHolocene in southern China is still limited. We present a multi-proxy record of paleoclimatic change in a crater lake, Lake Shuangchi. Based on the age-depth model from 210 Pb, 137 Cs and AMS14 C data, high-resolution mid-to late-Holocene climatic and environmental records were reconstructed using multiple indices(TOC, TN, C/N, δ13 C and grain size). Shuangchi underwent a marked change from a peat bog to a lake around 1.4 kaBP. The C3 plants likely dominated during 7.0–5.9 ka and 2.5–1.4 kaBP, while C4 plants dominated between 5.9–3.2 and 3.0–2.5 kaBP. Algae were dominant sources of organic matter in the lake sediments after 1.4 kaBP. Several intervals with high concentrations of coarser grain sizes might be due to flood events. These results reveal that several abrupt paleoclimatic events occurred around 6.6 ka, 6.1 ka, 5.9 ka, 3.0 ka, 2.5 ka and 1.4 kaBP. The paleoclimatic change recorded in the lake may be related to the migration of the Intertropical Convergence Zone(ITCZ) and El Ni?o-Southern Oscillation(ENSO) activity. 相似文献
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Sharyn M. Hickey Stuart R. Phinn Nik J. Callow Kimberly P. Van Niel Jeff E. Hansen Carlos M. Duarte 《Estuaries and Coasts》2017,40(5):1215-1226
Ecological (poleward) regime shifts are a predicted response to climate change and have been well documented in terrestrial and more recently ocean species. Coastal zones are amongst the most susceptible ecosystems to the impacts of climate change, yet studies particularly focused on mangroves are lacking. Recent studies have highlighted the critical ecosystem services mangroves provide, yet there is a lack of data on temporal global population response. This study tests the notion that mangroves are migrating poleward at their biogeographical limits across the globe in line with climate change. A coupled systematic approach utilising literature and land surface and air temperature data was used to determine and validate the global poleward extent of the mangrove population. Our findings indicate that whilst temperature (land and air) have both increased across the analysed time periods, the data we located showed that mangroves were not consistently extending their latitudinal range across the globe. Mangroves, unlike other marine and terrestrial taxa, do not appear to be experiencing a poleward range expansion despite warming occurring at the present distributional limits. Understanding failure for mangroves to realise the global expansion facilitated by climate warming may require a focus on local constraints, including local anthropogenic pressures and impacts, oceanographic, hydrological, and topographical conditions. 相似文献
14.
In view of the huge ice cover of 24.5 X 106 km3 in Antarctica, which accounts for over 90% by volume of the ice body on earth, the movement of Antarctic glaciers is a major
control on global sea-level change and climatic fluctuation. As recorded in the Quaternary deposits in King George Island,
West Antarctica, three rapid ablations can be recognized at 11000, 9000 and 6100 years ago and the global climate within the
past 6000 years is characterized by small-amplitude warm-cold fluctuation. Intertidal deposits at the north bank of the Shenzhen
Bay suggest a periodic variation in sea level in about every 670 years over the last 6000 years with low sea levels recorded
in the periods of 5500-4900, 3900-3600, 2400-2200 and 1300-1200 years ago. Between these periods the sea level rised for about
80 cm on average. The modern warming climate in the last century corresponds with a rise of sea level at the rate of 2~3 mm/a.
A state key project under the Antarctic Science & Technology Program (No. 905-02-04-03) and is partially financially supported
by the Natural Science Foundation of Guangdong Province. 相似文献
15.
Karen Helen Wiltshire Alexandra Kraberg Inka Bartsch Maarten Boersma Heinz-Dieter Franke Jan Freund Christina Gebühr Gunnar Gerdts Karina Stockmann Antje Wichels 《Estuaries and Coasts》2010,33(2):295-310
The Helgoland Roads time series is one of the richest temporal marine data sets available. Running since 1962, it documents
changes for phytoplankton, salinity, Secchi disc depths and macronutrients. Uniquely, the data have been carefully quality
controlled and linked to relevant meta-data, and the pelagic time series is further augmented by zooplankton, intertidal macroalgae,
macro-zoobenthos and bacterioplankton data. Data analyses have shown changes in hydrography and biota around Helgoland. In
the late 1970s, water inflows from the south-west to the German Bight increased with a corresponding increase in flushing
rates. Salinity and annual mean temperature have also increased since 1962 and the latter by an average of 1.67°C. This has
influenced seasonal phytoplankton growth causing significant shifts in diatom densities and the numbers of large diatoms (e.
g. Coscinodiscus wailesii). Changes in zooplankton diversity have included the appearance of the ctenophore Mnemiopsis leidyi. The macroalgal community also showed an increase in green algal and a decrease in brown algal species after 1959. Over 30
benthic macrofaunal species have been newly recorded at Helgoland over the last 20 years, with a distinct shift towards southern
species. These detailed data provide the basis for long-term analyses of changes on many trophic levels at Helgoland Roads. 相似文献
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Organic carbon isotopes in sediments have been frequently used to identify the source of organic matter.Here we present a study of organic δ~(13)C on two sediment profiles influenced by guano from Guangjin and Jinqing islands in the Xisha Archipelago,South China Sea.Organic matter from ornithogenic coral sand sediments has two main sources,guano pellets and plant residues,and their organic δ~(13)C(δ~(13)C_(OM)) are significantly different.Organic carbon δ~(13)C_(guano) is much higher thanδ~(13)C_(plants),and δ~(13)C_(OM)of bulk samples is intermediate.Based on a two-end-member mixing model,the proportions of guano-and plant-derived organic matter in the bulk samples were reconstructed quantitatively.The results showed that seabirds began to inhabit the islands around approximately1200-1400 AD,and that guano pellets have been an important source of soil organic matter since then.With the accumulation of guano-derived nutrients,plants began to develop prosperously on the islands in the last 200 years,which is reflected by the significant increase of plant-derived organic matter in the upper sediment layer.However,guano-derived organic matter decreased greatly in recent decades,indicating a rapid decrease in seabird population.Our results show that organic δ~(13)C can be effectively used to quantitatively determine different source contributions of OM to bulk ornithogenic coral sand sediments. 相似文献
18.
Fouad N. Ibrahim Dr. 《GeoJournal》1990,20(3):249-258
The author analyzes the changing conditions to which S Sudanese women have been subjected after their forced migration the war-ridden South to Khartoum. There, too, they are suffering from hunger, homelessness, lack of a basic needs. Being obliged to house and work illegally these women find themselves considered criminals by both the State and many of the so-called Arabs. Serious identity change is involved in the process of adaptationof these rural people to the hostile urban environment.This paper contains preliminary results of a field study conducted by the author in April 1989 within the framework of the research programme Identity in Africa of the German Research Society under the coordination of Helmut Ruppert and the author. Both, as well as Abdel Hamid Bakhit and Ismail Al Fihail have participated in this research on the migration of the Southerners to Khartoum. 相似文献
19.
《Geoforum》2015
In this article the author responds to the criticism that The Wrath of Capital: Neoliberalism and Climate Change Politics does not provide solutions to problems the book identifies. The author argues for the importance of developing a deep understanding of how neoliberalism has become the standard against which all social, economic, cultural, and political responses to climate change are measured. She goes onto re-iterate the main thesis of The Wrath of Capital, namely that this does not constitute an effective or equitable response to the challenges climate change presents. In her view understanding and thinking are important ingredients in developing a sustainable and equitable solution to climate change. 相似文献
20.
Xiao Keyan Zhang Xiaohua Chen Zhenghui Zhu Yusheng Song Guoyao Regional Mineral Potential Planning Division Chinese Academy of Geology Beijing 《中国地质大学学报(英文版)》2000,11(2)
GIS is the computing system for collecting’ processingand analyzing spatial geological information.Since 1980 s,with the mature of the GIS technology,geological depart-m ents in some developed country have started to construct thegeological spatial databases using the GIS technology,and al-so have developed the standard of spatial database construc-tion,for example,the STDS.In this case,vast geological ex-ploration data have been digitized in the first step.For exam-ple,the US Geologica… 相似文献