Download or read book Late Quaternary Southwestern African Terrestrial climate Signals in the Marine Record of Walvis Ridge SE Atlantic Ocean written by Jan-Berend Willem Stuut and published by . This book was released on 2001 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Namib written by John Kinahan and published by Boydell & Brewer. This book was released on 2022 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first full-length examination of the archaeology and history of the Namib Desert.This is a story of human survival over the last one million years in the Namib Desert - one of the most hostile environments on Earth. Namib reveals the resilience and ingenuity of desert communities and provides a vivid picture of our species' response to climate change, and ancient strategies to counter ever-present risk. Dusty fragments of stone, pottery and bone tell a history of perpetual transition, of shifting and temporary states of balance. Namib digs beneath the usual evidence of archaeology to uncover a world of arcane rituals, of travelling rain-makers, of intricate social networks which maintained vital systems of negotiated access to scarce resources. Ranging from the earliest evidence of human occupation, through colonial rule and genocide, to the invasion of the desert by South African troops during the First World War, this is the first comprehensive archaeology of the Namib. Among its important contributions are the reclaiming of the indigenous perspective during the brutal colonial occupation, and establishing new material links between the imperialist project in German South West Africa during 1885-1915 and the Third Reich, and between Nazi ideology and Apartheid.Southern Africa: University of Namibia Press/Jacana are the reclaiming of the indigenous perspective during the brutal colonial occupation, and establishing new material links between the imperialist project in German South West Africa during 1885-1915 and the Third Reich, and between Nazi ideology and Apartheid.Southern Africa: University of Namibia Press/Jacana are the reclaiming of the indigenous perspective during the brutal colonial occupation, and establishing new material links between the imperialist project in German South West Africa during 1885-1915 and the Third Reich, and between Nazi ideology and Apartheid.Southern Africa: University of Namibia Press/Jacana are the reclaiming of the indigenous perspective during the brutal colonial occupation, and establishing new material links between the imperialist project in German South West Africa during 1885-1915 and the Third Reich, and between Nazi ideology and Apartheid.Southern Africa: University of Namibia Press/Jacana
Download or read book Historical Change and Its Problem on the Relationship Between Natural Environments and Human Activities in Southern Africa written by Kazuharu Mizuno and published by . This book was released on 2010 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Environmental Background to Hominid Evolution in Africa written by International Union for Quaternary Research. Congress and published by . This book was released on 1999 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Late Quaternary History of Southern Hemisphere Mediterranean Climate Regions in the Western Cape South Africa and Southwestern Australian written by Brett Smith and published by . This book was released on 2010 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Tropical African Climate and Marine Sediment During Major Climate Transition written by Olubunmi Eniola and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents the late Miocene/early Pliocene climate transition (7-5 Ma) as recorded in marine sediments from Ocean Drilling Programme (ODP) Site 959 in the equatorial Atlantic off tropical West Africa, and a reconstruction of changing Holocene environments of the Eastern Tropical Atlantic (CHEETA) based on surface and core sediments from a transect along the Portuguese and NW African margin. The late Miocene to early Pliocene climate transition had irreversible consequences for atmospheric and ocean circulation leading to global cooling, northern hemisphere glaciations and modern climate conditions. In this study, continental climate, vegetation change and surface ocean dynamics at millennial time scale resolution is investigated from U\7' alkenone derived SST, leaf wax lipids and organic carbon records (TaG). Despite low TOC "1 %) which was highly variable at cm-scale (-2.5-5 kyr) resolution, ubiquitous evidence from alkenones (C37:2 and C37:3) and leaf wax lipids indicate that the primary climate signal was preserved. The UK3y' based SST estimates (24.8-29°G) showed pronounced warm and cool cycles in the magnitude of 4°C. Elevated leaf wax lipids n-alkanes (Cn C29, and C31) correspond with cool SSTs and indicate a coupled relationship between upwelling and atmospheric ocean circulation patterns which intensified around 5.6 Ma arguing for wind driven deposition from terrestrial sources related to the position and strength of the ITCZ. The high amplitude cyclic patterns in the ODP Site 959 records were investigated by time frequency analyses. The common 41 kyr in all records supports a response to high latitude climate forcing. The 75 kyr variations and lead/lag observed in the leaf waxes and SST records during the late Miocene to early Pliocene are probably related to continental ice volume variations. The study on surface sediments from the Portuguese and NW African margins, confirm the presence of two soil-specific biomarkers, branched GDGTs (expressed as the BIT index) and bacteriohopanepolyols (BHPs), in this region of almost exclusive aeolian export. TOC exceeding 2% and 013Corg gradients from -22.5%0 off Portugal to - 19%0 off W Africa identify areas of upwelling off Cape Blanc and the transition from C3 to C4 vegetation habitats in Northern Africa, respectively. Despite low signals of the molecular records, slightly stronger response of soil-marker BHPs in the sediments is attributed to preferential erosion of the upper, (oxic) part of the soil column in central African source areas, the proposed source for soil BHPs. An alternative explanation is that in situ production of the branched GDGTs may be responsible for the low BIT index. As yet there is no evidence of the soil BHPs, adenosylhopane produced in situ in marine systems and aeolian transport of GDGTs is yet to been proven. More studies on dust samples from continental margins needs to be carried out to validate this transport mechanism of branched GDGTs and BHPs. A compilation of first bulk geochemical and molecular results from a selection of cores from the Portuguese and NW African margin within an integrated chronological framework document the variations in marine sedimentation and constrain regional variations in continental climate and terrigenous supply since the last glacial period. TOC accumulation records document millennial scale variability in response to the African Humid Period. Carbon isotope trends pronounced during the last glacial maximum support organic matter input from C4 type vegetation during colder glacial periods. Preliminary molecular isotopic records of n-alkanes identify gaps in this study that will need further investigation to assess and confirm vegetation sources and continental climatic conditions over Northwest Africa.
Download or read book The South Atlantic written by Gerold Wefer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 815 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents results of recent projects in oceanography and marine geosciences (e.g. WOCE, JGOFS, PAGES, ODP) regarding present and past circulation in the South Atlantic. The objective of the book is to integrate results from both oceanographic and geological studies. As the connecting link between the Antarctic and the North Atlantic, the South Atlantic plays a crucial role with regard to the heat budget of the North Atlantic and to the biogeochemical budget of the global ocean. New results from studies of meridional water mass and heat transports are presented. The central theme of geological investigations is the reconstruction of current and productivity systems in the South Atlantic during the late Quaternary.
Download or read book Geologica Ultraiectina written by and published by . This book was released on 1957 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bibliography and Index of Geology written by and published by . This book was released on 1987 with total page 1416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Late Quaternary Climate and Sedimentary History Derived from N Alkanes Alkenones and Bulk Organic Carbon Analyses in Fujian Coast China written by Xiaoyun Li and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Late Quaternary Climate and Sedimentary History Derived From N-alkanes, Alkenones and Bulk Organic Carbon Analyses in Fujian Coast, China" by Xiaoyun, Li, 李瀟云, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Late Quaternary is an important period for paleoclimate study due to the boom of human civilization and thus its influence on climate conditions of the present interglacial period. In this study, a 52 m long borehole was drilled in a coastal embayment of Fujian, China, within which a thick marine layer from 16.05 to 32.60 m is found. Bulk organic geochemical analyses, containing total organic carbon content (TOC), carbon isotope ratio (δ13C), alkenones and n-alkanes, were analyzed for the whole core. Organic carbon isotope ratios (δ13C) of the sediment layers vary between -22.10/00 and -32.90/00, with higher values in the two marine sequences and lower in the two aquatic sequences. In the thick marine sequence, the δ13C is relatively stable, and it becomes gradually enriched from the base upwards and depleted rapidly at the top, indicating a full cycle of marine transgression and regression. The n-alkanes exhibit a similar trend, with several indexes, i.e., maximum concentration (Cmax), carbon preference index (CPI), average chain length (ACL), terrestrial-aquatic ratio (TAR), Paq and C31/(C29+C31). These results suggest the control of EAM and sea-level change in the sedimentary processes. Analysis on alkenones shows sea surface temperature (SST) variations as well as sea-level oscillations in the study site. DOI: 10.5353/th_b5351040 Subjects: Paleoclimatology - Quaternary Sedimentation and deposition - China - Min River (Fujian Sheng) Paleoclimatology - China - Fujing Sheng
Download or read book Paleo environmental Effects of the Mid Pleistocene Transition in the Tropical Atlantic and Equatorial Africa written by Enno Schefuss and published by . This book was released on 2003 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Late Quaternary Paleoenvironmental Changes in Southern Africa and Madagascar written by Lixin Wang and published by . This book was released on 2016 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research reconstructed paleoclimatic and paleoenvironmental conditions using proxy data derived from cave stalagmites, an aeolian sand ramp and fluvial slackwater deposits (SWDs) in Namibia and Madagascar, a broad region influenced by a wide variety of atmospheric and oceanic circulation systems. The stalagmites provided accurately dated high-resolution multiproxy records of Holocene hydroclimate variations in northwest Madagascar and northern Namibia. An 8260-yr stalagmite record for northwest Madagascar documents multiple significant droughts in the Holocene and offers insights into the causes of megafaunal extinctions on the island over the last 2000 years. Three stalagmite records from northern Namibia record climate variations in northwest and northcentral Namibia over the past 4000 years. Comparison of the northern Namibia stalagmite data suggests that there were changes in the influence of Atlantic versus Indian Ocean moisture during the Holocene depending on the dynamics of the Congo Air Boundary. The sedimentology of a sand ramp in the Konkiep valley of southern Namibia, dated by 11 optically stimulated luminescence (OSL) ages, revealed periods of strong winds and great aridity at 49-29 ka and 24-15 ka, and less windy and wetter conditions with fluvial activity at 24-29 ka. Slackwater deposits on the Namibian side of the Orange River, dated by OSL, provided a record of major floods in the lower Orange River at 6.8-8 ka, 5.3-6.5 ka, 3.4-4.6 ka, and 0.5-1.2 ka, indicating increased summer rainfall in the interior of Southern Africa at these times. These records are compared with other published evidence of climate change in southern Africa and Madagascar. The records are also compared with major climate events in the Northern Hemisphere to see how the Southern Hemisphere tropics and subtropics responded to changing conditions in the Northern Hemisphere. The records derived from this research greatly improve our understanding of the late Quaternary paleoclimate of southern Africa and Madagascar, and make important contributions to the southern hemisphere paleoclimate database.
Download or read book Palaeoecology of Africa and the Surrounding Islands Volume 27 written by K. Heine and published by CRC Press. This book was released on 2001-01-01 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: These papers derive from a workshop on "Quaternary Sedimentary Records in Central Africa and their Palaeoenvironmental Interpretation", held at the 15th INQUA Congress. They mainly cover the Late Quaternary to Holocene climate and environmental history of today's rainforest regions.
Download or read book Mineral Dust written by Peter Knippertz and published by Springer. This book was released on 2014-09-01 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents state-of-the-art research about mineral dust, including results from field campaigns, satellite observations, laboratory studies, computer modelling and theoretical studies. Dust research is a new, dynamic and fast-growing area of science and due to its multiple roles in the Earth system, dust has become a fascinating topic for many scientific disciplines. Aspects of dust research covered in this book reach from timescales of minutes (as with dust devils, cloud processes and radiation) to millennia (as with loess formation and oceanic sediments), making dust both a player and recorder of environmental change. The book is structured in four main parts that explore characteristics of dust, the global dust cycle, impacts of dust on the Earth system, and dust as a climate indicator. The chapters in these parts provide a comprehensive, detailed overview of this highly interdisciplinary subject. The contributions presented here cover dust from source to sink and describe all the processes dust particles undergo while travelling through the atmosphere. Chapters explore how dust is lifted and transported, how it affects radiation, clouds, regional circulations, precipitation and chemical processes in the atmosphere and how it deteriorates air quality. The book explores how dust is removed from the atmosphere by gravitational settling, turbulence or precipitation, how iron contained in dust fertilizes terrestrial and marine ecosystems, and about the role that dust plays in human health. We learn how dust is observed, simulated using computer models and forecast. The book also details the role of dust deposits for climate reconstructions. Scientific observations and results are presented, along with numerous illustrations. This work has an interdisciplinary appeal and will engage scholars in geology, geography, chemistry, meteorology and physics, amongst others with an interest in the Earth system and environmental change. body>
Download or read book A Climate Model Study of the Role of Global Climate in the Late Pleistocene Migration of Anatomically Modern Humans Out of Africa written by Shannon Leigh Carto and published by . This book was released on 2006 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: According to the "Out-of-Africa 2" theory of human evolution all living humans today descend from a group of Anatomically Modern Homo sapiens or Anatomically Modem Humans that evolved in Africa 200,000 years ago and subsequently migrated out of Africa and spread into the rest of the World around 100,000 years. As a result an interest has developed in establishing a concrete theory of the factors that compelled and/or motivated our ancestors to venture out of their African origins at this time. Interestingly, the Earth's Last Glacial Cycle also dates from this period--stretching from 115,000 to 10,000 years ago. Current paleoclimate evidence suggests that the climatic repercussions of this glacial cycle in Africa resulted in a shift towards a drier and somewhat cooler climate state and the fragmentation of the formerly extensive forested African landscape. As a result, theories of early human migration have cited African climate change during the late Pleistocene as a determinant; however, the mechanisms responsible for the development of hyper-arid conditions in Africa at this time have remained unresolved.Although, past global climate change has been ascribed to changes in radiative forcing and changes in atmospheric carbon dioxide, recent paleoclimate studies have revealed that African climate is sensitive to changes in SSTs in the Atlantic, as it appears that subtropical Africa was more arid when North Atlantic sea surface temperatures (SSTs) were cold during glacial periods. The forcing mechanism believed to be responsible for the development of these cold SSTs are the so-called Heinrich Events that are documented as massive surges of icebergs (from high-latitude ice sheets) into the North Atlantic Ocean during high-latitude glaciations. These Heinrich events resulted in the release of large quantities of freshwater into the North Atlantic, which in turn led to a weakening on the global ocean thermohaline circulation and widespread cooling throughout the region. In particular, marine sediment records from the Nordic Sea document a widespread cooling and ice-rafting event that occurred around 105 kya, known as Heinrich event 9.In order to investigate the climate processes responsible for promoting cooler and drier conditions in Africa during the migration event of AMH (around 100 kya) I used the University of Victoria Earth System Climate Model (UVic ESCM) to conduct two climate model experiments that compared the global-scale response of climate at 105 kya, in particular the Atlantic Ocean and the African climate system, to: 1) orbitally-controlled solar radiation and atmospheric carbon dioxide forcing appropriate for 105 kya and 2) the combined effect of orbitally-controlled solar radiation and atmospheric carbon dioxide at 105 kya, and North Atlantic freshwater forcing ...
Download or read book Late quaternary climate changes in the Horn of Africa written by M. Umer and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Quaternary History of African Monsoon written by Yulong Zhao and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is devoted to reconstruct the Quaternary history of African monsoon and its influences on suspended loads of the Nile River and dust production in Sahara. The materials used in this study come from two sites (MD90-964 in the eastern Levantine Basin and ODP Site 964 in the Ionian Sea) in the eastern Mediterranean Sea. Based on clay mineralogy, grain sizes, carbonate and Corg contents, and XRF core scanning analyses of Core MD90-964, we have reconstructed history of the Nile suspended discharges, precipitation in North Africa, and Nile paleoflood events during the last 1.75 Ma. On the basis of the planktonic foraminiferal Delta(18)O record of Core MD90-964, we have established for the first time in the eastern Mediterranean Sea a high-resolution planktonic foraminiferal (G. ruber) Delta(18)O record that penetrates the Quaternary period. The ODP Site 964 allows us to establish the variations of Saharan dust inputs to the eastern Mediterranean Sea during the last 1.5 Ma. Our results indicate that both fluvial sediments from the Nile and Saharan eolian dust inputs to the eastern Mediterranean Sea are greatly influenced by the variability of African monsoon. The glacial/interglacial cycles and other orbital-scale climatic events, such as the “Mid-Pleistocene Transition”, can also affect climate changes in North Africa to a minor extent.
