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Paleoclimatic Reconstructions Of The Northern Red Sea During The Holocene Interfered From Stable Isotope Records Of Modern And Fossil Corals And Molluscs
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Book Synopsis Paleoclimatic Reconstructions of the Northern Red Sea During the Holocene Interfered from Stable Isotope Records of Modern and Fossil Corals and Molluscs by : Yaser Ahmed Moustafa
Download or read book Paleoclimatic Reconstructions of the Northern Red Sea During the Holocene Interfered from Stable Isotope Records of Modern and Fossil Corals and Molluscs written by Yaser Ahmed Moustafa and published by . This book was released on 2000 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Paleoclimatic Reconstructions of the Northern Red Sea During the Holocene Inferred from Stable Isotope Records of Modern and Fossil Corals and Molluscs by : Yaser Ahmed Moustafa
Download or read book Paleoclimatic Reconstructions of the Northern Red Sea During the Holocene Inferred from Stable Isotope Records of Modern and Fossil Corals and Molluscs written by Yaser Ahmed Moustafa and published by . This book was released on 2000 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Late Quaternary Paleoceanographic and Paleoclimatologic History of the Red Sea During the Last 380,000 Years by : Susanne Geiselhart
Download or read book Late Quaternary Paleoceanographic and Paleoclimatologic History of the Red Sea During the Last 380,000 Years written by Susanne Geiselhart and published by . This book was released on 1998 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Quaternary Dating Methods by : Mike Walker
Download or read book Quaternary Dating Methods written by Mike Walker and published by John Wiley & Sons. This book was released on 2013-04-30 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: This introductory textbook introduces the basics of dating, the range of techniques available and the strengths and limitations of each of the principal methods. Coverage includes: the concept of time in Quaternary Science and related fields the history of dating from lithostratigraphy and biostratigraphy the development and application of radiometric methods different methods in dating: radiometric dating, incremental dating, relative dating and age equivalence Presented in a clear and straightforward manner with the minimum of technical detail, this text is a great introduction for both students and practitioners in the Earth, Environmental and Archaeological Sciences. Praise from the reviews: "This book is a must for any Quaternary scientist." SOUTH AFRICAN GEOGRAPHICAL JOURNAL, September 2006 “...very well organized, clearly and straightforwardly written and provides a good overview on the wide field of Quaternary dating methods...” JOURNAL OF QUATERNARY SCIENCE, January 2007
Book Synopsis Late Quaternary Paleoceanographic and Paleoclimatologic History of the Red Sea During the Last 380000 Years by : Susanne Geiselhart
Download or read book Late Quaternary Paleoceanographic and Paleoclimatologic History of the Red Sea During the Last 380000 Years written by Susanne Geiselhart and published by . This book was released on 1998 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Study of Early Holocene Paleoprecipitation Record from Freshwater River Mussel Shell at the Cooper's Ferry Site, Idaho and Their Archaeological Implications by : Alejandra P. Jimenez
Download or read book A Study of Early Holocene Paleoprecipitation Record from Freshwater River Mussel Shell at the Cooper's Ferry Site, Idaho and Their Archaeological Implications written by Alejandra P. Jimenez and published by . This book was released on 2015 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of [delta]18O held in freshwater bivalve shell carbonate are useful for reconstructing paleoclimates and environmental changes and inform interpretations about past human behavior and periods of culture change. Stable isotope analyses ([delta]18O) of Margaritifera falcata shells found at the Cooper's Ferry archaeological site located in the lower Salmon River canyon of Idaho were used to determine paleoclimate conditions during the early Holocene. In a previous study, a limited number of mussel shell [delta]18O values suggested early Holocene climates were generally moister. This thesis presents a higher-resolution isotope record that reveals far greater variation and extremes in precipitation values from 9,000 to 8,000 RYBP. By comparing prehistoric mussel shell isotope data to isotope records from modern shell and modern rainfall records this study provides a baseline against which prehistoric paleoprecipitation conditions can be evaluated. By examining the patterns in which archaeological shell [delta]18O reflects variability in regional climate conditions, human-environmental interactions can then be considered in order to make predictions about foraging behaviors.
Book Synopsis The Northern North Atlantic by : Priska Schäfer
Download or read book The Northern North Atlantic written by Priska Schäfer and published by Springer Science & Business Media. This book was released on 2001-04-02 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: The northern North Atlantic is one of the regions most sensitive to past and present global changes. This book integrates the results of an interdisciplinary project studying the properties of the Greenland-Iceland-Norwegian Seas and the processes of pelagic and benthic particle formation, particle transport, and deposition in the deep-sea sediments. Ice-related and biogeochemical processes have been investigated to decipher the spatial and temporal variability of the production and fate of organic carbon in this region. Isotopic stratigraphy, microfossil assemblages and paleotemperatures are combined to reconstruct paleoceanographic conditions and to model past climatic changes in the Late Quaternary. The Greenland-Iceland-Norwegian Seas can now be considered one of the best studied subbasins of the world`s oceans.
Book Synopsis Holocene Paleoenvironmental Change in Pamlico Sound, North Carolina by : Candace A. Grand Pre
Download or read book Holocene Paleoenvironmental Change in Pamlico Sound, North Carolina written by Candace A. Grand Pre and published by . This book was released on 2006 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary 231Pa/230Th by : Andrea Burke
Download or read book Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary 231Pa/230Th written by Andrea Burke and published by . This book was released on 2012 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean's role in climate change over the last deglaciation. I present a new method for rapid radiocarbon analyses as a means of age-screening deep-sea corals for further study. Based on age survey results, I selected forty corals from the Drake Passage and thirteen from the Reykjanes Ridge off Iceland and dated them with uranium series isotopes. The uranium series dates give independent ages that allow radiocarbon to be used as a tracer of circulation and carbon cycle changes. The radiocarbon records generated from the Drake Passage corals show increased stratification in the Southern Ocean during the last glacial maximum (LGM) that disappeared during the start of the deglaciation as atmospheric CO2 began to rise during Heinrich Stadial 1 (H1). Considering these data and using a simple mass budget calculation, I show that the drop in atmospheric radiocarbon activity during H1 can be explained given direct carbon exchange between the radiocarbon-depleted deep ocean and atmosphere, e.g. through the Southern Ocean. The Drake Passage radiocarbon records also show evidence for decreased air-sea gas exchange in the Southern Ocean during the Antarctic Cold Reversal/Bølling-Allerød coincident with the hiatus in the deglacial CO2 rise. During this time period in the North Atlantic, radiocarbon reconstructions from deep-sea corals collected from off Iceland show a similar ventilation rate to that observed today and during the Holocene. To further investigate changes in North Atlantic ventilation over the last deglaciation, I used an inverse model to assess the consistency of sedimentary 231Pa/230Th ratios from the Holocene, H1, and the LGM with the modern circulation. Although sedimentary 231Pa/230Th has been used to infer changes in the strength of the meridional overturning circulation in the past, I find that published data are consistent with the modern circulation during the LGM and H1. These findings highlight the importance of giving due regard to the uncertainties in the behavior and spatial distribution of paleoceanographic tracers.
Book Synopsis Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary 231Pa/230Th by : Andrea Burke (Ph. D.)
Download or read book Constraining Circulation Changes Through the Last Deglaciation with Deep-sea Coral Radiocarbon and Sedimentary 231Pa/230Th written by Andrea Burke (Ph. D.) and published by . This book was released on 2012 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radioactive isotopes can be used in paleoceanography both for dating samples and as tracers of ocean processes. Here I use radiocarbon and uranium series isotopes to investigate the ocean's role in climate change over the last deglaciation. I present a new method for rapid radiocarbon analyses as a means of age-screening deep-sea corals for further study. Based on age survey results, I selected forty corals from the Drake Passage and thirteen from the Reykjanes Ridge off Iceland and dated them with uranium series isotopes. The uranium series dates give independent ages that allow radiocarbon to be used as a tracer of circulation and carbon cycle changes. The radiocarbon records generated from the Drake Passage corals show increased stratification in the Southern Ocean during the last glacial maximum (LGM) that disappeared during the start of the deglaciation as atmospheric CO2 began to rise during Heinrich Stadial 1 (H1). Considering these data and using a simple mass budget calculation, I show that the drop in atmospheric radiocarbon activity during H1 can be explained given direct carbon exchange between the radiocarbon-depleted deep ocean and atmosphere, e.g. through the Southern Ocean. The Drake Passage radiocarbon records also show evidence for decreased air-sea gas exchange in the Southern Ocean during the Antarctic Cold Reversal/Bølling-Allerød coincident with the hiatus in the deglacial CO2 rise. During this time period in the North Atlantic, radiocarbon reconstructions from deep-sea corals collected from off Iceland show a similar ventilation rate to that observed today and during the Holocene. To further investigate changes in North Atlantic ventilation over the last deglaciation, I used an inverse model to assess the consistency of sedimentary 231Pa/230Th ratios from the Holocene, H1, and the LGM with the modern circulation. Although sedimentary 231Pa/230Th has been used to infer changes in the strength of the meridional overturning circulation in the past, I find that published data are consistent with the modern circulation during the LGM and H1. These findings highlight the importance of giving due regard to the uncertainties in the behavior and spatial distribution of paleoceanographic tracers.
Book Synopsis Late Quaternary paleoceanographic and paleoclimatologic history o the Red Sea during the last 380.000 years by : Susanne Geiselhart
Download or read book Late Quaternary paleoceanographic and paleoclimatologic history o the Red Sea during the last 380.000 years written by Susanne Geiselhart and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Long-term Environmental Change in Arctic and Antarctic Lakes by : Reinhard Pienitz
Download or read book Long-term Environmental Change in Arctic and Antarctic Lakes written by Reinhard Pienitz and published by Springer Science & Business Media. This book was released on 2007-11-08 with total page 579 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerns about the effects of global climate change have focused attention on the vulnerability of circumpolar regions. This book offers a synthesis of the spectrum of techniques available for generating long-term environmental records from circumpolar lakes.
Book Synopsis Reconstruction of Quaternary Paleo-circulation in the Western Arctic Ocean Based on a Neodymium Isotope Record from the Northwind Ridge by : Rachael E. Gray
Download or read book Reconstruction of Quaternary Paleo-circulation in the Western Arctic Ocean Based on a Neodymium Isotope Record from the Northwind Ridge written by Rachael E. Gray and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: An understanding of past ocean circulation in the Arctic is critical for interpretations of past global ocean and atmospheric circulation, as well as predictions of future conditions. The Arctic Ocean plays a major role in global climate, due to its contributions to both the North Atlantic Deep Water (and subsequently the Atlantic Meridional Overturning Circulation) and the planet's albedo (due to sea ice cover). A sediment core from the Northwind Ridge in the western Arctic Ocean, ~800 km north of Alaska, has been sampled for measurement of radiogenic isotope ratios of neodymium and strontium. Sediment grain coatings were leached from the bulk sediment and measured for 87/86Sr and [epsilon]Nd, a proxy for seawater source. Two leaching solutions, one using buffered acetic acid and the second using hydroxylamine hydrochloride, were applied to sediments. Strontium data suggests that acetic acid best captures the seawater signal, while hydroxylamine hydrochloride leaching likely caused clay contamination of the hydrogenous data. [epsilon]Nd ratios were compared with independent lithologic proxies measured on the core and with results of earlier radiogenic-isotope studies in the Arctic Ocean. Data obtained suggest that radiogenic waters dominated the western Arctic Ocean during the estimated Early Pleistocene, probably due to increased Pacific water inputs and/or enhanced brine exclusion from sea ice formation on the Siberian shelves. These conditions likely indicate relatively warm climatic environments with predominantly seasonal sea ice, and thus can be potentially used as a paleo-analog for the projected near-future state of the Arctic. Further upcore, in the estimated Middle to Late Pleistocene, [epsilon]Nd values decrease overall, with high-amplitude fluctuations corresponding to glacial-interglacial cyclicity. Strongly non-radiogenic values in glacial intervals suggest the predominance of inputs from the Canadian Shield eroded by the Laurentide ice sheet. More radiogenic but gradually decreasing interglacial values indicate a change from Pacific to Atlantic water influence during the Middle to Late Pleistocene. Further isotope work on other cores may clarify the mechanisms and extent of this shift in circulation patterns.
Book Synopsis Arctic and North Atlantic Paleo-environmental Reconstructions from Lake Sediments by : Gregory A. de Wet
Download or read book Arctic and North Atlantic Paleo-environmental Reconstructions from Lake Sediments written by Gregory A. de Wet and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT ARCTIC AND NORTH ATLANTIC PALEO-ENVIRONMENTAL RECONSTRUCTIONS FROM LAKE SEDIMENTS MAY 2017 GREGORY A. DE WET, B.Sc., BATES COLLEGE M.Sc., UNIVERSITY OF MASSSCHUSETTS, AMHERST Ph.D., UNIVERSITY OF MASSACHUSETTS, AMHERST Directed by: Drs. Raymond S. Bradley and Isla S. Castañeda There are few fields in the discipline of Earth Science that hold more relevancy in 2017 than studies of earth's climate. Called the "perfect problem" considering its complexity and magnitude, climate change will continue to be one of the greatest challenges humanity will face in the 21st century. And while numerical models provide valuable information on conditions in the future, the results from these simulations must be contextualized by the past. Climate reconstructions from paleo-environmental archives, even from periods colder or different from what we are experiencing today, provide that context. Every piece of information gleaned from these studies informs our collective knowledge of the climate system. In some cases, environmental reconstructions may include proxies for anthropogenic as well as climatological information, directly addressing one of the most important questions in climate science: how does changing climate affect humans? The following chapters of this dissertation are exercises in trying to understand climate change in one of the most climatically sensitive regions on earth - the high northern latitudes. While my doctoral studies cover a wide range of timescales, it is broadly unified by the focus on the Arctic. In some cases, my research spans multiple glacial/interglacial cycles, in others the concentration is on the past few thousand years. In all cases, however, the goal is to utilize lacustrine sedimentary archives to inform our knowledge of climatic change in this important region. One of the most rewarding aspects of this Ph.D. has been the creativity I have been afforded in working towards that goal. Chapter One of this dissertation involves the analysis of organic molecules, specifically bacterial membrane lipids called branched glycerol dialkyl glycerol tetraethers (brGDGTs), to sediments from Lake El'gygytgyn. These biomarkers allow for a quantitative reconstruction of temperature from multiple interglacial periods over a million years ago. Our data suggests that "super interglacial" Marine Isotope Stage 31 may have in fact lasted much longer than previously thought in the Arctic, with implications for Antarctic ice sheet extent and CO2 concentrations highly relevant to our future. Though the extraction and analysis of these biomarkers is expensive and time-consuming, the data is highly valuable and informative. Conversely in some cases more "quick and dirty" techniques are sufficient to reconstruct important processes or factors back through time (e.g. the presence of a glacier within a lake catchment) at relatively low cost, and therefore are highly useful. The chapters dealing with Lake Gjøavatnet in Svalbard (Chapter Two) or the application of Fourier Transform Infrared (FTIR) spectroscopy to lake sediments (Chapter Five) exhibit how such techniques can also be highly informative. In Chapter Two, using a combination of core-scanning data and relatively simple destructive analyses (%loss-on-ignition, bulk carbon isotopes), we reconstructed past fluctuations in glacier extent over the Holocene, as well as identified intervals that may have been related to freshwater pulses in Fram Strait. Chapter Five is focused mainly on expanding and confirming the use of FTIR spectroscopy to Arctic lake sediments to reconstruct biogenic silica and organic matter concentrations through time. Though potentially a less direct climate proxy than paleotemperature from brGDGTs, this new technique allows for more rapid analyses using less sediment than previous methods, a valuable advance. Chapters Three and Four are in many ways the confluence of these earlier stages of my Ph.D., where we apply a wide range of proxies to answer questions related to climate and human population dynamics. The use of biomarkers is expanded in these projects, where a broad suite of organic molecules are used to reconstruct both climate and other paleo-environmental conditions, including vegetation changes, variations in pH, and potentially anthropogenic influences. Coupled with some of the more "basic" techniques described above, we characterize an environmental disturbance in the Faroe Islands ~2200 years ago that may be evidence for the first appearance of humans in the archipelago (Chapter Three). In Chapter Four, we explore the application of brGDGTs (among other proxies) to reconstruct temperature change in southwest Greenland during the period of Norse settlement and subsequent abandonment. This work is part of an ongoing investigation into the efficacy and calibration of this promising proxy in a locale where climate change likely had a dramatic impact on the fragile communities living there. In summary, I have not attempted to unify these chapters into a single climatological context (though some of my work, such as in the Faroes and Greenland, is highly related). Instead I present them as they are, individual projects that each have their own goals and merits within the broad framework of paleoclimatology. As I mentioned above, one of my favorite things about this field is the creativity we are afforded in our attempts to answer questions about the past. This Ph.D. has been an exercise in that creativity, focused in the high northern latitudes, and centered around the archive of lake sediments.
Download or read book The Red Sea written by Najeeb M.A. Rasul and published by Springer. This book was released on 2015-04-02 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a broad overview of the current state of knowledge regarding the Red Sea, from its geological formation and oceanographic development to the environmental influences on its ecology and the changes it is experiencing due to the rapid development of its coastlines and role as one of the world’s major transport routes. The book gathers invited contributions from researchers with an interest in the geology, geophysics, oceanography and environment of the Red Sea, while also providing comprehensive new data and a complete review of the literature. It will be of interest not only to researchers actively studying the sea and its surroundings, but will also appeal to all those involved in planning and managing the Red Sea, its environment, its resources and the countries which rely on its existence.
Book Synopsis Characterization of Paleoclimate and Marine Processes Associated with Holocene Sedimentation on the Chukchi Margin, Arctic Ocean by : Chandawimal H. E. R. Siriwardana
Download or read book Characterization of Paleoclimate and Marine Processes Associated with Holocene Sedimentation on the Chukchi Margin, Arctic Ocean written by Chandawimal H. E. R. Siriwardana and published by . This book was released on 2014 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reconstructing sedimentary processes associated with the deglacial events in the Chukchi Margin is necessary to evaluate the deglacial and Holocene flow regime in the Chukchi margin area, which was the purpose of this study. To provide context for the paleoceanographic reconstruction, the modern system was explored using multispectral band ratio analysis of the marine portions of Landsat images. Terrestrial processes were investigated using visual geomorphic description and unsupervised classification to define land cover classes and sediment sources. Thermal images and band ratios clearly demonstrate that flow regimes influence sediment transport, variations of the plant pigment, sea ice content and particle density. Using 1040 samples from five sediment cores and 27 surface samples from the Chukchi Margin, sediment composition was evaluated by comparison of visible and near infrared (VNIR) derivative spectroscopy, while sediment texture was explored using laser-particle grain size analysis. Varimax-rotated principal component analysis (VPCA) on several different multivariate data sets was employed to address the multi-colinearity inherent in this type of dataset. VNIR derivative spectroscopy was used to identify mineralogical compositions of dolomite + illite; goethite + chlorophyllide-a; smectite + chlorite and calcite in the Chukchi Margin area. Strong influence of Arctic Oscillation from the mid-Holocene to present enhanced the iron minerals with a provenance from Russian seas. Enhancement of the smectite + chlorite component during 6000 to 3500 yr BP exhibits an influx of Pacific waters related to mid Holocene Warming. The enhancement of the dolomite + illite component in recent years might indicate dominant sediment provenance from east in the Victoria Island/McKenzie River basin. IIlite was identified as an appropriate water mass tracer for a reverse flow from the Arctic into the North Pacific because of its prominence and abundance in the Mackenzie River drainage basin and on the west Arctic Sea shelf (Nwadua, 2013). The overall trends in the grain size and mineralogy of the surface samples and remote sensing data of modern processes suggest possible changes in flow regime and the sediment transport in the west and east of the Barrow canyon area. In terms of grain size, four principal components of sediment deposition related to anchor ice, nepheloid flows, suspension freezing and intermittent suspension were observed. Grain size components documents that periods of high anchor ice formation are correlated with low nepheloid flows. Intermittent suspension dominates in ice-free intervals with low contributions from suspension freezing. There was evidence of an enhanced offshore transport of sediment, reworked by bottom currents when intermittent suspension was high and suspension freezing was low. High amplitude fluctuations of grain size VPCA modes around 8000 yrs BP (in JPC6 and JPC8) and in recent years (in JPC6, JPC8 and JPC 16) may be correlated with the prevalence of Holocene paleoclimatic cycles related to Mid-Holocene melting with enhanced Pacific inflow and recent cooling/ warming and volcanic events. Shorter oscillations (multi-centennial) shown in these VPCA modes may relate to possible variations of atmosphere-ocean circulation patterns, primarily the low frequency patterns associated with the Arctic Oscillation (AO). Wavelet analysis suggests cyclicity of ~1500 or > 2000 yr are common for all components in Holocene.
Book Synopsis Recent Corals of the Marshall Islands by : John West Wells
Download or read book Recent Corals of the Marshall Islands written by John West Wells and published by . This book was released on 1954 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: An ecologic and taxonomic analysis of living reef- and non-reef-building corals at Bikini and other Marshall Islands atolls.
