Publisher: Elsevier   (Total: 3200 journals)

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Showing 801 - 1000 of 3200 Journals sorted alphabetically
Dermatologic Clinics     Full-text available via subscription   (Followers: 4, SJR: 1.311, CiteScore: 3)
Dermatologica Sinica     Open Access   (SJR: 0.339, CiteScore: 1)
Desalination     Hybrid Journal   (Followers: 14, SJR: 1.955, CiteScore: 6)
Design Studies     Hybrid Journal   (Followers: 35, SJR: 0.941, CiteScore: 3)
Deutsche Zeitschrift für Akupunktur     Full-text available via subscription   (Followers: 2)
Development Engineering     Open Access   (Followers: 1, SJR: 0.346, CiteScore: 1)
Developmental & Comparative Immunology     Hybrid Journal   (Followers: 7, SJR: 0.899, CiteScore: 3)
Developmental Biology     Hybrid Journal   (Followers: 27, SJR: 2.087, CiteScore: 3)
Developmental Cell     Full-text available via subscription   (Followers: 49, SJR: 6.558, CiteScore: 7)
Developmental Cognitive Neuroscience     Open Access   (Followers: 20, SJR: 2.718, CiteScore: 5)
Developmental Review     Hybrid Journal   (Followers: 9, SJR: 2.8, CiteScore: 6)
Developments in Agricultural Economics     Full-text available via subscription   (Followers: 3)
Developments in Agricultural Engineering     Full-text available via subscription   (Followers: 2)
Developments in Aquaculture and Fisheries Science     Full-text available via subscription   (Followers: 11, SJR: 0.198, CiteScore: 1)
Developments in Atmospheric Science     Full-text available via subscription   (Followers: 27)
Developments in Clay Science     Full-text available via subscription   (Followers: 1, SJR: 0, CiteScore: 1)
Developments in Crop Science     Full-text available via subscription   (Followers: 5)
Developments in Earth and Environmental Sciences     Full-text available via subscription   (Followers: 3)
Developments in Earth Surface Processes     Full-text available via subscription   (Followers: 1, SJR: 0.12, CiteScore: 0)
Developments in Economic Geology     Full-text available via subscription   (Followers: 3, SJR: 1.611, CiteScore: 3)
Developments in Environmental Economics     Full-text available via subscription   (Followers: 4)
Developments in Environmental Modelling     Full-text available via subscription   (Followers: 8, SJR: 0.118, CiteScore: 0)
Developments in Environmental Science     Full-text available via subscription   (Followers: 3)
Developments in Food Science     Full-text available via subscription   (Followers: 2)
Developments in Geochemistry     Full-text available via subscription   (Followers: 2)
Developments in Geotechnical Engineering     Full-text available via subscription   (Followers: 6, SJR: 0.189, CiteScore: 0)
Developments in Geotectonics     Full-text available via subscription   (Followers: 2, SJR: 2.544, CiteScore: 4)
Developments in Integrated Environmental Assessment     Full-text available via subscription   (Followers: 4)
Developments in Marine Biology     Full-text available via subscription   (Followers: 9)
Developments in Marine Geology     Full-text available via subscription   (Followers: 15)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 3)
Developments in Palaeontology and Stratigraphy     Full-text available via subscription   (Followers: 4)
Developments in Petroleum Science     Full-text available via subscription   (Followers: 1)
Developments in Petrology     Full-text available via subscription   (Followers: 1)
Developments in Plant Genetics and Breeding     Full-text available via subscription   (Followers: 9, SJR: 0.65, CiteScore: 2)
Developments in Precambrian Geology     Full-text available via subscription   (Followers: 8)
Developments in Quaternary Science     Full-text available via subscription   (Followers: 5)
Developments in Sedimentology     Full-text available via subscription   (Followers: 2)
Developments in Soil Science     Full-text available via subscription   (Followers: 10)
Developments in Volcanology     Full-text available via subscription   (Followers: 3)
Developments in Water Science     Full-text available via subscription   (Followers: 12)
Diabetes & Metabolic Syndrome: Clinical Research & Reviews     Full-text available via subscription   (Followers: 23, SJR: 0.876, CiteScore: 2)
Diabetes & Metabolism     Full-text available via subscription   (Followers: 77, SJR: 1.326, CiteScore: 3)
Diabetes Research and Clinical Practice     Hybrid Journal   (Followers: 76, SJR: 1.538, CiteScore: 4)
Diagnostic and Interventional Imaging     Full-text available via subscription   (SJR: 0.552, CiteScore: 1)
Diagnostic Histopathology     Full-text available via subscription   (Followers: 14, SJR: 0.176, CiteScore: 0)
Diagnostic Microbiology and Infectious Disease     Hybrid Journal   (Followers: 12, SJR: 1.157, CiteScore: 2)
Diagnostics in Neuropsychiatry     Open Access   (Followers: 1)
Diálisis y Trasplante     Full-text available via subscription  
Diamond and Related Materials     Hybrid Journal   (Followers: 11, SJR: 0.686, CiteScore: 2)
Differential Geometry and its Applications     Full-text available via subscription   (Followers: 2, SJR: 0.791, CiteScore: 1)
Differentiation     Hybrid Journal   (Followers: 1, SJR: 1.259, CiteScore: 3)
Digestive and Liver Disease     Hybrid Journal   (Followers: 15, SJR: 1.303, CiteScore: 2)
Digestive and Liver Disease Supplements     Full-text available via subscription   (Followers: 5)
Digital Applications in Archaeology and Cultural Heritage     Hybrid Journal   (Followers: 10, SJR: 0.412, CiteScore: 2)
Digital Signal Processing     Hybrid Journal   (Followers: 30, SJR: 0.55, CiteScore: 3)
Disability and Health J.     Hybrid Journal   (Followers: 19, SJR: 1.015, CiteScore: 2)
Discourse, Context & Media     Open Access   (Followers: 23, SJR: 0.654, CiteScore: 1)
Discrete Applied Mathematics     Hybrid Journal   (Followers: 13, SJR: 0.785, CiteScore: 1)
Discrete Mathematics     Hybrid Journal   (Followers: 8, SJR: 0.851, CiteScore: 1)
Discrete Optimization     Full-text available via subscription   (Followers: 8, SJR: 0.539, CiteScore: 1)
Disease-a-Month     Full-text available via subscription   (Followers: 4, SJR: 0.323, CiteScore: 1)
Dislocations in Solids     Full-text available via subscription  
Displays     Hybrid Journal   (SJR: 0.293, CiteScore: 1)
DNA Repair     Hybrid Journal   (Followers: 3, SJR: 3.181, CiteScore: 4)
DoctorConsult - The J.. Wissen für Klinik und Praxis     Full-text available via subscription  
Domestic Animal Endocrinology     Hybrid Journal   (Followers: 6, SJR: 0.887, CiteScore: 2)
Douleurs : Evaluation - Diagnostic - Traitement     Full-text available via subscription   (SJR: 0.136, CiteScore: 0)
Droit, Déontologie & Soin     Full-text available via subscription   (Followers: 2, SJR: 0.1, CiteScore: 0)
Drug and Alcohol Dependence     Hybrid Journal   (Followers: 23, SJR: 1.715, CiteScore: 4)
Drug Discovery Today     Full-text available via subscription   (Followers: 184, SJR: 2.008, CiteScore: 6)
Drug Discovery Today: Disease Mechanisms     Full-text available via subscription   (Followers: 8)
Drug Discovery Today: Disease Models     Full-text available via subscription   (Followers: 10, SJR: 0.218, CiteScore: 1)
Drug Discovery Today: Technologies     Full-text available via subscription   (Followers: 13, SJR: 0.822, CiteScore: 2)
Drug Discovery Today: Therapeutic Strategies     Full-text available via subscription   (Followers: 12)
Drug Metabolism and Pharmacokinetics     Full-text available via subscription   (Followers: 6, SJR: 0.652, CiteScore: 2)
Drug Resistance Updates     Hybrid Journal   (Followers: 3, SJR: 3.986, CiteScore: 11)
Dyes and Pigments     Hybrid Journal   (Followers: 2, SJR: 0.819, CiteScore: 4)
Dynamical Properties of Solids     Full-text available via subscription  
Dynamics of Atmospheres and Oceans     Hybrid Journal   (Followers: 15, SJR: 0.604, CiteScore: 1)
Early Childhood Research Quarterly     Hybrid Journal   (Followers: 24, SJR: 1.814, CiteScore: 3)
Early Human Development     Hybrid Journal   (Followers: 13, SJR: 1.041, CiteScore: 2)
Earth and Planetary Science Letters     Hybrid Journal   (Followers: 212, SJR: 3.166, CiteScore: 5)
Earth Science Frontiers     Full-text available via subscription   (Followers: 6, SJR: 0.55, CiteScore: 1)
Earth System Governance     Open Access  
Earth-Science Reviews     Hybrid Journal   (Followers: 16, SJR: 3.334, CiteScore: 8)
Eating Behaviors     Hybrid Journal   (Followers: 5, SJR: 0.898, CiteScore: 2)
EBioMedicine     Open Access   (SJR: 2.895, CiteScore: 3)
EClinicalMedicine     Open Access  
Ecohydrology & Hydrobiology     Full-text available via subscription   (Followers: 2, SJR: 0.539, CiteScore: 2)
Ecological Complexity     Hybrid Journal   (Followers: 7, SJR: 0.753, CiteScore: 2)
Ecological Economics     Hybrid Journal   (Followers: 190, SJR: 1.657, CiteScore: 4)
Ecological Engineering     Hybrid Journal   (Followers: 4, SJR: 1.042, CiteScore: 3)
Ecological Engineering : X     Open Access  
Ecological Genetics and Genomics     Full-text available via subscription   (Followers: 3, SJR: 0.111, CiteScore: 0)
Ecological Indicators     Hybrid Journal   (Followers: 19, SJR: 1.406, CiteScore: 4)
Ecological Informatics     Hybrid Journal   (Followers: 4, SJR: 0.778, CiteScore: 2)
Ecological Modelling     Hybrid Journal   (Followers: 96, SJR: 1.084, CiteScore: 3)
Econometrics and Statistics     Hybrid Journal   (Followers: 1)
EconomiA     Open Access   (Followers: 1)
Economía Informa     Open Access   (Followers: 1)
Economía UNAM     Open Access   (Followers: 1)
Economic Analysis and Policy     Hybrid Journal   (Followers: 9, SJR: 0.634, CiteScore: 1)
Economic Modelling     Hybrid Journal   (Followers: 28, SJR: 0.966, CiteScore: 2)
Economic Systems     Hybrid Journal   (Followers: 2, SJR: 0.565, CiteScore: 1)
Economics & Human Biology     Hybrid Journal   (Followers: 3, SJR: 2.123, CiteScore: 3)
Economics Letters     Hybrid Journal   (Followers: 61, SJR: 0.738, CiteScore: 1)
Economics of Education Review     Hybrid Journal   (Followers: 30, SJR: 1.482, CiteScore: 2)
Economics of Transportation     Partially Free   (Followers: 14, SJR: 1.276, CiteScore: 2)
Ecosystem Services     Hybrid Journal   (Followers: 8, SJR: 1.743, CiteScore: 5)
Ecotoxicology and Environmental Safety     Hybrid Journal   (Followers: 11, SJR: 1.201, CiteScore: 4)
Edited Series on Advances in Nonlinear Science and Complexity     Full-text available via subscription  
Educación Química     Open Access   (Followers: 1, SJR: 0.209, CiteScore: 0)
Education for Chemical Engineers     Hybrid Journal   (Followers: 5, SJR: 0.273, CiteScore: 1)
Educational Research Review     Hybrid Journal   (Followers: 193, SJR: 2.963, CiteScore: 6)
Egyptian Informatics J.     Open Access   (Followers: 5, SJR: 0.406, CiteScore: 3)
Egyptian J. of Anaesthesia     Open Access   (Followers: 2, SJR: 0.285, CiteScore: 1)
Egyptian J. of Aquatic Research     Open Access   (Followers: 1, SJR: 0.36, CiteScore: 1)
Egyptian J. of Basic and Applied Sciences     Open Access  
Egyptian J. of Critical Care Medicine     Open Access   (Followers: 1)
Egyptian J. of Forensic Sciences     Open Access   (Followers: 8, SJR: 0.277, CiteScore: 1)
Egyptian J. of Petroleum     Open Access   (Followers: 2, SJR: 0.548, CiteScore: 2)
Egyptian J. of Remote Sensing and Space Science     Open Access   (Followers: 23, SJR: 0.803, CiteScore: 3)
Egyptian Pediatric Association Gazette     Open Access   (Followers: 1, SJR: 0.123, CiteScore: 0)
Egyptian Rheumatologist     Open Access   (Followers: 4, SJR: 0.295, CiteScore: 1)
EJC Supplements     Open Access   (Followers: 3, SJR: 1.358, CiteScore: 3)
EJVES Short Reports     Open Access   (Followers: 1, SJR: 0.208, CiteScore: 0)
Electoral Studies     Hybrid Journal   (Followers: 45, SJR: 1.3, CiteScore: 1)
Electric Power Systems Research     Partially Free   (Followers: 23, SJR: 1.048, CiteScore: 3)
Electricity J.     Hybrid Journal   (Followers: 2, SJR: 0.632, CiteScore: 1)
Electrochemistry Communications     Open Access   (Followers: 15, SJR: 1.606, CiteScore: 5)
Electrochimica Acta     Hybrid Journal   (Followers: 23, SJR: 1.439, CiteScore: 5)
Electronic Commerce Research and Applications     Hybrid Journal   (Followers: 6, SJR: 0.818, CiteScore: 3)
Electronic J. of Biotechnology     Open Access   (SJR: 0.537, CiteScore: 2)
Electronic Notes in Discrete Mathematics     Full-text available via subscription   (Followers: 2, SJR: 0.262, CiteScore: 0)
Electronic Notes in Theoretical Computer Science     Open Access   (Followers: 3, SJR: 0.287, CiteScore: 1)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 11)
Elsevier Ergonomics Book Series     Full-text available via subscription   (Followers: 5)
Elsevier Geo-Engineering Book Series     Full-text available via subscription   (Followers: 4)
Elsevier Ocean Engineering Series     Full-text available via subscription   (Followers: 2)
Elsevier Oceanography Series     Full-text available via subscription   (Followers: 5)
EMC - AKOS - Trattato di Medicina     Hybrid Journal  
EMC - Anestesia-Reanimación     Hybrid Journal  
EMC - Anestesia-Rianimazione     Hybrid Journal  
EMC - Aparato Locomotor     Hybrid Journal  
EMC - Cirugía General     Hybrid Journal   (Followers: 1)
EMC - Cirugía Otorrinolaringológica y Cervicofacial     Full-text available via subscription  
EMC - Cirugía Plástica Reparadora y Estética     Full-text available via subscription  
EMC - Cosmetologia Medica e Medicina degli Inestetismi Cutanei     Full-text available via subscription  
EMC - Dermatología     Full-text available via subscription   (Followers: 1)
EMC - Ginecología-Obstetricia     Full-text available via subscription   (Followers: 1)
EMC - Kinesiterapia - Medicina Física     Full-text available via subscription  
EMC - Medicina Riabilitativa     Full-text available via subscription  
EMC - Neurologia     Full-text available via subscription  
EMC - Otorinolaringoiatria     Full-text available via subscription  
EMC - Otorrinolaringología     Full-text available via subscription  
EMC - Pediatría     Full-text available via subscription   (Followers: 1)
EMC - Podología     Full-text available via subscription  
EMC - Técnicas Quirúrgicas - Aparato Digestivo     Full-text available via subscription  
EMC - Técnicas Quirúrgicas - Ortopedia y Traumatología     Full-text available via subscription  
EMC - Tecniche chirurgiche - Chirurgia Addominale     Full-text available via subscription  
EMC - Tecniche Chirurgiche - Chirurgia Generale     Full-text available via subscription  
EMC - Tecniche Chirurgiche - Chirurgia ORL e Cervico-Facciale     Full-text available via subscription  
EMC - Tecniche Chirurgiche - Chirurgia Ortopedica     Full-text available via subscription  
EMC - Tecniche chirurgiche - Chirurgia Plastica, Ricostruttiva ed Estetica     Full-text available via subscription  
EMC - Tecniche chirurgiche - Chirurgia Vascolare     Full-text available via subscription  
EMC - Tecniche Chirurgiche Torace     Full-text available via subscription  
EMC - Tratado de medicina     Full-text available via subscription  
EMC - Urgenze     Full-text available via subscription  
EMC - Urología     Full-text available via subscription  
Emergency Medicine Clinics of North America     Full-text available via subscription   (Followers: 21, SJR: 0.479, CiteScore: 1)
Emerging Markets Review     Hybrid Journal   (Followers: 11, SJR: 1.113, CiteScore: 2)
Emotion, Space and Society     Hybrid Journal   (Followers: 12, SJR: 1.292, CiteScore: 2)
Endeavour     Hybrid Journal   (Followers: 4, SJR: 0.198, CiteScore: 1)
Endocrinología y Nutrición     Full-text available via subscription   (Followers: 2)
Endocrinología y Nutrición (English Edition)     Full-text available via subscription   (Followers: 2)
Endocrinology and Metabolism Clinics of North America     Full-text available via subscription   (Followers: 28, SJR: 1.27, CiteScore: 3)
Endoscopia     Open Access  
Energy     Partially Free   (Followers: 44, SJR: 1.99, CiteScore: 6)
Energy and Buildings     Hybrid Journal   (Followers: 12, SJR: 2.061, CiteScore: 5)
Energy Conversion and Management     Hybrid Journal   (Followers: 16, SJR: 2.537, CiteScore: 7)
Energy Conversion and Management : X     Open Access  
Energy Economics     Hybrid Journal   (Followers: 41, SJR: 1.916, CiteScore: 4)
Energy for Sustainable Development     Hybrid Journal   (Followers: 11, SJR: 1.065, CiteScore: 3)
Energy Policy     Partially Free   (Followers: 77, SJR: 1.994, CiteScore: 5)
Energy Procedia     Open Access   (Followers: 4)
Energy Reports     Open Access   (Followers: 5)
Energy Research & Social Science     Full-text available via subscription   (Followers: 8, SJR: 2.063, CiteScore: 5)
Energy Storage Materials     Full-text available via subscription   (Followers: 4, SJR: 5.208, CiteScore: 13)
Energy Strategy Reviews     Open Access   (Followers: 8, SJR: 1.009, CiteScore: 2)
EnergyChem     Hybrid Journal   (Followers: 1)
eNeurologicalSci     Open Access   (SJR: 0.293, CiteScore: 1)
Enfermedades Infecciosas y Microbiología Clínica     Full-text available via subscription   (SJR: 0.373, CiteScore: 1)
Enfermería Clínica     Full-text available via subscription   (Followers: 3, SJR: 0.216, CiteScore: 0)
Enfermería Clínica (English Edition)     Hybrid Journal   (Followers: 1)
Enfermería Intensiva     Full-text available via subscription   (Followers: 2, SJR: 0.144, CiteScore: 0)
Engineering : The official journal of the Chinese Academy of Engineering and Higher Education Press     Open Access   (Followers: 1, SJR: 0.503, CiteScore: 2)
Engineering Analysis with Boundary Elements     Hybrid Journal   (Followers: 2, SJR: 1.219, CiteScore: 2)
Engineering Applications of Artificial Intelligence     Hybrid Journal   (Followers: 14, SJR: 0.874, CiteScore: 4)
Engineering Failure Analysis     Hybrid Journal   (Followers: 67, SJR: 0.933, CiteScore: 2)

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Similar Journals
Journal Cover
Developments in Earth and Environmental Sciences
Number of Followers: 3  
 
  Full-text available via subscription Subscription journal
ISSN (Print) 1571-9197
Published by Elsevier Homepage  [3200 journals]
  • Foreword
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10



      PubDate: 2012-12-15T09:31:08Z
       
  • Introduction
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10



      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 1 Major Stages and Methodology in the Evolution of Geological
           Concepts
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the scientific hypotheses of Earth's evolution, the development of the modern theory of Earth's lithospheric shell formation, and the methodology of constructing a general theory of Earth's global evolution. Most general geological hypotheses of Earth's evolution played a very important role in forming the natural-scientific weltanschauung of the geologists. The chapter highlights the physical theory of the formation of the Solar System published by P. S. Laplace in early nineteenth century. He suggested that the stars, including Sun, formed as a result of gravity concentration and compression of the cosmic gas whose existence was already known to astronomers. Gas compression is accompanied by its heating. That is why, Laplace believed that all stars are hot and are radiating heat and light (at those times, the existence of radioactive processes was not even suspected). As the cosmic gas is in permanent motion, it not only heats up when compressed but also spins up. As a result, in addition to the central star, a gas disk occurs around it, which concentrates into hot planets. Paleomagnetic studies on continents have also played a large role in the rebirth of the mobilist ideas and in the creation on that basis of the modern geological theory. Studies of rocks' magnetic properties showed that the rocks containing magnetic minerals are capable of “remembering” the ancient magnetic field of Earth.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 2 Structure and Composition of Modern Earth
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the structure and composition of modern Earth. Earth is the third planet from the Sun in the Solar System. It revolves around the Sun in an orbit that is close to circular at the average distance of 149.6 million km. Looking from the side of the celestial sphere's North Pole, Earth and the other planets revolve around the Sun counterclockwise. The average velocity of Earth's motion on its orbit is 29.765 km/s and the revolution period (duration of a year) is 365.24 solar days or 3.147×107 s. Earth has its own direct axial revolution whose period is 24 hours 56 minutes 4.1 seconds or 8.616×104 seconds. Earth's mass is 5.977×1027 g, average radius 6371 km, the surface area is 510.08 million km2, average density 5.52 g/cm3, and average gravity acceleration at the surface reaches 981 gal. Earth's shape is described as a geoid, which represents equipotential gravity surface. Outside of the continents, the geoid coincides with the undisturbed water surface of the World Ocean. On the continents, the surface is calculated from gravity data or satellite observations. The best approximation of the geoid is ellipsoid of revolution. The geoid deviations from such an ellipsoid are between +86 and +105 m. They are caused both by a nonuniform mass distribution within Earth and by dynamic processes developing in the mantle and Earth's lithospheric shell.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 3 Origin of Earth, its Past and Future
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the origin of Earth, its past, and its future. According to the modern cosmogonic concepts, the Earth group's planets, including Earth and the Moon, formed due to accretion of solid particles in the gas–dust protoplanetary cloud. Usually, the initial density of the interstellar clouds is not high enough for gravity compression and development of the independent star- and planet-forming processes. Supernova explosions, however, are accompanied by shock waves in the interstellar medium. If such waves hit a gas–dust cloud, pressure and matter density drastically increase on the wave-front. The result may be clots capable of the subsequent compression due to the self-gravity. That is why supernova explosions not only deliver the new matter into the cosmic space but also serve as the mechanism, which eventually leads to the formation of new generations of stars and their surrounding planetary systems. Apparently, such a situation arose about 4.56 BY ago in the vicinity of the protosolar gas–dust cloud. After having received an impulse of the initial compression and evolution and having been added a new matter, the cloud subsequently began to compress irreversibly, now affected by its own gravity field. With the compression, pressure and temperature in the cloud's center rapidly increased. Gradually, a giant gas clot, the Proto-Sun, formed in that zone. However, prior to the “kindling” of the nuclear reactions and the Proto-Sun entering the main sequence of the stellar evolution, its temperature was relatively low, not above 1000–1500 °C, and the radiation was mostly in the infrared (IR) and red spectral bands.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 4 Process of Earth's Core Separation
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the process of Earth's core separation. According to the most probable Earth origin model under the Schmidt hypothesis, Earth and other Solar System planets formed due to the accretion of cold, homogeneous matter from the protoplanetary cloud. Two general scenarios of a high-density core separation within Earth may be suggested: (1) the core formed simultaneously with the planet growth or immediately upon its formation and (2) the high-density core separation began much later after Earth heated up, and the differentiation process of Earth's matter expanded over billions of years and is even continuing today. The first scenario is the least probable. It could have occurred only under the “hot” origin of Earth and a brief accretion period on the order of 10 MMY. For a rapid planet differentiation with the separation of a high-density core within it, the planetary matter should undergo a practically global melting, as happened with the Moon. For Earth, such a suggestion is in direct contradiction with the available geological and geochemical data. The second scenario is based on a homogeneous and relatively long accretion under which the Earth depths remained relatively cold, with the temperature not to exceed 800–1500 K. Initial stages of the Earth differentiation process were determined by its initial heat-store.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 5 Earth Energetics
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      One of the fundamental issues in planetary geophysics is the sources of energy determining the heat regime and supporting tectonic activity on Earth. It may be resolved only in a close association with the modern data about Earth's composition, structure, and evolution. This chapter presents the analysis of Earth's energy balance to estimate its heat loss during the past geological epochs by which the evolution of the planet's tectonic activity can be determined. Three global energy processes dominate inside Earth. First, it is Earth's matter gravity differentiation by density. It results in Earth's stratification into the high-density iron-oxide core, the residual silicate mantle, the light aluminosilicate crust, and the hydrosphere with the atmosphere. Second, it is the decay of radioactive elements causing the release of heat energy. Third is the tidal interaction between Earth and the Moon. All other endogenous energy sources are either immeasurably smaller than the three listed above or totally reversible due to the mass exchange of the mantle convection. For instance, the transition energy of mineral associations affected by the pressure in the ascending and descending convective flows has opposite signs. That is why any effect of such reactions onto the summary endogenous energy balance of Earth may be disregarded, although they may affect the configuration of the mantle convective flows.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 6 Earth's Tectonic Activity and its Nature
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses Earth's tectonic activity and its nature. It reviews the motivating forces arising within the lithospheric shell proper. Disregarding the side pressure from the adjacent lithospheric plates, two major factors are usually identified that are capable of causing the plate motions relative to one another and to the mantle. A first one is sliding of the oceanic plates from the slopes of asthenospheric lenses positioned underneath the mid-oceanic ridges. A second one is associated with sinking of the cold, therefore heavier oceanic plates into the hot mantle through the subduction zones. Earth's tectonic activity is the intensity of the entire gamut of geological processes deforming its lithospheric shell and causing any forms of magmatism within this shell. When the lithospheric plate tectonics appeared, it became clear that some measure of the movement of the lithospheric plate ensemble may serve as a demonstrative estimate of the Earth's average tectonic activity. Such measure may be represented by the rate of the plates' relative displacement. However, it appears that the most general, convenient, and physically justified estimate of the Earth's tectonic activity is its energy measure. This energy is eventually defined by the depth of heat flow released from the mantle. Indeed, any motions of the matter and its magmatic transformations, which lead to the planet's tectonic activity, are eventually converted to heat and are lost with the Earth's heat radiation. That is exactly why the depth heat flow may be a natural measure of the Earth's tectonic activity.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 7 Evolution of the Crust-Formation Processes in Earth's History
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the evolution of the crust-formation processes in earth's history. The oldest stage of Earth's formation (the pre-geological or Katarchaean stage) lasted approximately 600 MMY from the moment of Earth's emergence 4.6 BY ago through the beginning of its tectonic activity in Early Archaean, about 4.0 BY ago. Earth at that time was a relatively cold celestial body. All matter within it was at temperatures way below its melting temperature. There was no tectonomagmatic activity. Nevertheless, Earth during Katarchaean was not a tectonically dead planet. First, its insides at that time were gradually warmed up by the radioactive element decay energy and by the energy of tidal interaction with the Moon. These events were preparing the conditions for Earth transitioning to tectonically active evolution. Second, the exogenous tectonics of the tidal origin played a significant role in Katarchaean (especially in Early Katarchaean). This evolutionary stage may be called the “crypto-tectonic stage.” First clear and intense manifestations of the endogenous tectonomagnetic activity on Earth are reliably identified in the beginning of Archaean close to 3.8 BY ago. The beginning of Earth's tectonomagmatic activity was prepared by the radiogenic and tidal heating of the primordial Earth's matter to the temperature when the primary melts appeared within the upper mantle. That was followed by a drastic and maybe even “shock” activation of the tectonomagnetic activity. First, it happened due to “pumping” into the then formed asthenosphere of the tidal energy from the Moon–Earth interaction. Later, it proceeded because of the energy release from gravity differentiation of Earth matter.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 8 Lithospheric Plate Tectonics in Early Proterozoic and
           Phanerozoic
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the lithospheric plate tectonics in early Proterozoic and Phanerozoic. It treats lithospheric plate tectonics as a geological theory dealing with the structure, emergence, and mutual displacements of the lithospheric plates accompanied by their deformations, magmatic manifestations, and other processes resulting in the formation of Earth's crust and the associated economic deposits. The lithosphere consists of Earth's crust and the underlying subcrustal lithosphere. The continental crust is mostly composed of granitoids and rocks of medium composition usually overlain by sediments. The total thickness of the crust is 30–80 km. The consolidated oceanic crust is thinner, 6.5–7 km, and comprises of basalts, gabbro, and serpentinites. The sediment thickness over the oceanic crust is greater in the coastal zones and pinches out to zero over the crests of mid-oceanic ridges. On average, it is close to 500 m. The oceanic crust is underlain by massive ultramafic rocks. The total thickness of oceanic lithospheric plates ranges between 2–3 km in the oceanic rift zone areas and 80–90 km near the ocean shores. The thickness of ancient continental plates reaches 200–220 km. Earth's temperature gradually increases with depth. Underneath the oceanic plates, the mantle temperature reaches partial melting of the mantle rocks. For this reason, the base of the lithosphere underneath the oceans is assumed to be the surface of the mantle rocks melting with its solidus temperature.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 9 Continental Drift in Earth's Geological History
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      A theoretical analysis and modeling of the mantle convection processes shows that the supercontinents could form at the interval of about 800 MMY and only after Archaean. Only four such supercontinents could have formed over the entire post-Archaean time interval. This chapter discusses the spatial positions of these supercontinents and the continental (and ocean) drift in Earth's Precambrian evolution. It provides a review of these reconstructions in their historical sequence from the older to the younger. The reconstructions are based on geological and paleoclimatic data. The same-age or same-type structures, formations, and climatic provinces is aligned with one another. In particular, for the Monogaea reconstruction, the data on tillite and tilloid distribution on the Early Proterozoic continents is used in the chapter. The criterion of compact grouping of known Early Proterozoic tillite deposits is utilized in consideration of possible inherited continent locations on Earth's surface in the subsequent geological epochs. Under such preconditions, the “center of gravity” for the geographic locations of the identified tillites and tilloids approximately defines the center of gravity for the supercontinent proper.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 10 Major Patterns of Economic Deposit Concentration within Earth's
           Crust
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      The chapter discusses the issue of the origins of commercial deposits and the major patterns of their spatial and temporal distribution from the position of the most general physical theory of the Earth's global evolution. Major patterns of ore matter concentration in the Earth's crust and the very origin of the economic deposits (especially endogenous deposits) are closely associated with the global evolution processes. On the other hand, the exogenically emerged commercial deposits are strongly related also with the evolution of the global climate. At the same time, the identified patterns in the spatial and temporal distribution of commercial deposits can often serve as reliable indicators of the very process of the Earth's evolution. For this reason, numerous metallogenic concepts were mostly based on the once reigning theoretical ideas about the evolution of geotectonic and petrologo-geochemical processes. After the emergence of the global evolution theory based on plate tectonics, it became possible to discuss all these complex problems from a unified theoretical position. In-depth analysis showed that metallogenic epochs are inimitable moments in the planet's evolution. This is understandable as, thermodynamically, Earth is an open dissipative system irreversibly losing its endogenous energy to outer space. Therefore, its evolution must be irreversible.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 11 Hydrosphere The Patterns of its Origin and Evolution
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      The Earth's hydrosphere and atmosphere evolutionary regimes are crucial in the determination of the climate evolution, the emergence and evolution of life, and the issue of commercial deposits, including combustible deposits. This chapter discusses the formation of the geospheres. The water mobility factors in Archaean and thereafter significantly differed. Thus, to estimate the mantle degassing, it is necessary to put together two degassing equations with different mobility factors and combine those by the degassing process continuity condition at the Archaean–Proterozoic time boundary. In this case, the two equations include three variables: two water mobility factors and the original water mass in the Earth's matter. That is, to solve the problem quantitatively, it is necessary to determine and insert into the equations three independent boundary conditions. The first boundary condition may be the total mass of water in the present-day ocean and the continental crust. A second boundary condition is the total water mass on Earth. A third pivotal point for the calculations could be the hydrosphere's water mass at an intermediate point in time. Using additional geological data, it is a solvable problem. As the ocean gradually increased in volume, there should have been a moment in its evolution when the oceanic water covered the mid-oceanic ridge crests with their associated rift zones.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 12 Atmosphere Origin and Physicochemical Aspects of Evolution
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the origin and physicochemical aspects of evolution of atmosphere. A specific feature in the origin and evolution of the Earth's atmosphere was the paucity of Earth's matter (compared with the Sun) in volatile and mobile elements and compounds. Had it been otherwise, the present-day atmosphere and hydrosphere would have been much thicker and denser. Maison estimated the relative hydrogen content on Earth (vs. silicon) is 106.6 times lower than in outer space; nitrogen is 105.9 times; carbon is 104 times; and noble gases are 106–1014 times lower. So despite the commonality in outer space of such volatile compounds as H2, He, N2, H2O, CO2, CH4, NH3, and so on, they turned out to be very scarce in Earth's matter. It is believed that such substantial differentiation in primordial Earth's matter occurred in the pre-planetary stage of the Solar system's evolution, when the Sun was at the t-Taurus stage of stellar evolution. It may have happened because of the intense sweep of volatile and mobile components from the internal portions of the protoplanetary gas–dust cloud into its periphery and into the giant planet formation zone.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 13 Adiabatic Theory of the Greenhouse Effect
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the adiabatic theory of the greenhouse effect. Earth has relatively dense atmosphere. For this reason, the heat transfer within its lower, densest layer (the troposphere), 12 km thick, occurs mostly through the air convection and not only through radiation as is represented by the proponents of the “classical” treatment of the greenhouse effect. In a dense atmosphere, the dominating heat transfer is always by the air flow—that is, through the convective mass exchange where the warm air expands and rises up and the cold air compresses and goes down. The radiation heat transfer dominates only the tenuous layers of the stratosphere, mesosphere, and thermosphere. A main inference from this is that the average temperature distribution in the troposphere must by close to the adiabatic distribution—that is, to such distribution that takes into account the air expansion and cooling when it rises and, conversely, its compression and heating when it goes down. Under the adiabatic process, the gas temperature is always proportionate with the gas pressure p to a power of the adiabatic exponent a, which depends on the effective heat capacity of the gas mixture.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 14 Evolution of Earth's Global Climate
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the evolution of Earth's global climate. The most important definitive factor of the Earth's climatic conditions is its surface temperature. Temperatures during the past epochs may be deduced from the oxygen isotopic shifts, for instance, in the marine Flintstones, which usually form in equilibrium with the surrounding water. It is known from isotope geochemistry that the δ18O value in marine Flintstones substantially depends on the temperature of the water, where the siliceous sediments were deposited. Based on such determinations, it is usually assumed that a high atmospheric temperature occurred already in Archaean about 3.4 BY ago. By mid-Archaean, the oceanic water temperature reached +70 °С. It is not clear to this day, however, to what extent the δ18O values in ancient Flintstones reflect their origin and, most important, the temperatures of the water where these Flintstones formed: the isotope ratio in the Flintstones may have been affected also by the same ratio in the oceanic water. It is possible that the observed regular decline of the δ18O values in the Flintstones is not only due to the oceanicwater temperature change but also due to other reasons causing regular δ18O value decline in the Archaean oceanic waters.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 15 Origin and Major Stages of Life Evolution on Earth
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10

      This chapter discusses the main stages in the emergence and evolution of life on Earth and geologo-climatic processes, which led to the appearance on Earth of conditions conducive to the existence of higher life forms. The most important factor of life on Earth is the environment of the habitation of live organisms in the oceans and on continents. And the habitation environment is determined first of all by the Earth's climate—that is, by the composition, state, and temperature of the atmosphere whose origin and evolution was associated with the planet's degassing and with life activity of the organisms. The Earth's degassing begun at the Archaean/Katarchaean time boundary that resulted in the formation during Archaean of a relatively high-density, substantially reducing carbon dioxide–nitrogen–methane atmosphere. In Archaean also appeared volcanoes, differentiated magmatic rocks, and first isolated marine basins, which joined by the end Archaean into a single albeit shallow-water ocean. Due to a high atmospheric pressure, 5–6 atm., average oceanic water temperature, same as the troposphere temperature at sea level, rose in Archaean from +60 to +70 °С. As the atmosphere has carbon dioxide composition, the oceanic water has acidic reaction with pH ≈ 5.5–6.

      PubDate: 2012-12-15T09:31:08Z
       
  • Conclusions
    • Abstract: 2011
      Publication year: 2011
      Source:Developments in Earth and Environmental Sciences, Volume 10



      PubDate: 2012-12-15T09:31:08Z
       
  • The Fly River, Papua New Guinea: Environmental Studies in an Impacted
           Tropical River System
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9



      PubDate: 2012-12-15T09:31:08Z
       
  • List of Contributors
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9



      PubDate: 2012-12-15T09:31:08Z
       
  • Geomorphology, Hydrology, and Climate of the Fly River System
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      The Fly River occupies a large humid tropical drainage basin in western Papua New Guinea. In its upper reaches, the river system occupies steep mountain country but further downstream, there is a 500-km floodplain reach that is backed up by the Strickland. This chapter examines the climate, hydrology, and geomorphology of the system. It also describes the changes that have occurred in response to disposal of tailings and waste rock from the Ok Tedi mine. These include extensive deposition, especially in the upper part of the system, and rising water levels that have had a major effect on the floodplain.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 2 Texture, Geochemistry, and Mineralogy of Sediments of the Fly
           River System
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      The Fly River system in western Papua New Guinea is one of the largest river systems in world with an annual sediment discharge estimated at 100×106 t. Located at the headwaters of the Ok Tedi, a tributary of the Fly River, is the Mount Fubilan copper-gold mine. The mine, which uses open-cut methods to exploit a low-grade porphyry ore body, commenced operations in 1984. Waste materials from mining operations comprising approximately 55Mt of overburden and 30Mt of ex-mill tailings, are discharged each year into the Ok Tedi. Erosional and fluvial processes then transport a large proportion of this waste into the lower reaches of the river system where it is either deposited in a range of riverine settings or released into the marine waters of the Gulf of Papua and Torres Strait. This chapter examines the impact of mining at Mount Fubilan on the texture, geochemistry, and mineralogy of the sediments deposited in the channel bed and along the levees of the Ok Tedi and Fly Rivers.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 3 The Rapid Spread of Mine-Derived Sediment across the Middle Fly
           River Floodplain
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      In 1990, 5 years after mining-related waste was introduced into the Fly River system by Ok Tedi Mining Limited, an annual monitoring program was instituted to detect the spatial extent of mine-derived sediment across the Middle Fly River floodplain. Initial sampling, which relied on elevated particulate copper detection as a mine signal, revealed a surprisingly rapid and extensive deposition rate across the floodplain. This led to more intensive sampling and sediment core analysis over subsequent years through 1995. Some 840 separate cores were taken across the 3,500km2 floodplain and about 4,000 separate particulate copper measurements were made. Mine-derived sediment was found to spread rapidly across tens of kilometers in just a few years due to injection of mainstem sediment laden flows out a 900km long network of floodplain channels (tributary and tie channels). These flows entered off-river water bodies (ORWB) and spilled from their banks onto the adjacent plain, creating a depositional web across the floodplain. Consequently, even in the first annual samples, 75% of all off-river water body samples had elevated particulate copper levels. The overbank flows dropped sediment rapidly as it spread across the plain, leaving an exponential decline in deposition rate with distance from the nearest channel bank that fell to very low values within a kilometer. Using the defined exponential functions and measured channel lengths as well as estimates of deposition rates in the ORWB, we calculate that about 180Mt of sediment (∼130,000 tonnes of copper) was deposited on the floodplain environment between 1985 and 1994, equaling about 40% of the total load entering the Middle Fly at D’Albertis Junction. Approximately, one-half of this load was deposited via floodplain channels and the other half by mainstem overbank deposition. This is consistent with the separate rough estimates of 20% of the total discharge being pushed out the floodplain channels and another 20% spilled overbank during flood events. This initial response to increased mine-derived loading may differ from subsequent years as bed aggradation (which was relatively minor at this time) would increase the frequency and duration of flooding. The rapid and extensive spread of sediment via floodplain channels has left a long-term legacy of mine-derived sediment across the full extent of the Middle Fly River floodplain environment.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 4 Processes, Sediments, and Stratigraphy of the Fly River Delta
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      The Fly River in Papua New Guinea is a major supplier of sediment to the ocean; approximately 100×106 tonnes are supplied to the delta annually. This paper reviews the considerable accumulated knowledge of transport processes, sediments, and stratigraphy in this regionally and globally important system. The body of work suggests a small portion (
      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 5 Variable Styles of Sediment Accumulation Impacting Strata
           Formation on a Clinoform: Gulf of Papua, Papua New Guinea
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      A detailed study of the seabed near the Fly River in the Gulf of Papua has revealed a high degree of heterogeneity in accumulation styles along and across the margin and in the resulting strata. Seven distinct styles are identified with an eighth regime characterized by negligible accumulation on a 100-y timescale. Accumulation Types I and II indicate steady-state accumulation at high (>1.0cm/y) and low (
      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 6 A Mass Balance for Sediment and Copper in the Rivers, Estuaries,
           Shelf and Slope of the Gulf of Papua, Papua New Guinea
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      Rivers supply 276×106 molCuyr−1 to the Gulf of Papua, and nearly all of this is in the particulate phase. Based on an extensive coring program over the last decade, we find that only 156×106 molCuyr−1 is buried on the inner shelf and slope. We found that suspended and bottom sediment aluminum was the best predictor of Cu concentration in sediment, whereas organic carbon and sulfur were less useful for this purpose. Cu/Al ratios in the river suspended sediment were higher than in sediments of the inner shelf and slope sediments, and we propose that Cu is released from riverine aluminosilicate clay particles, and sorbed to a more mobile (colloidal') aluminosilicate phase for transport into the Hiri Gyre of the northern Coral Sea.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 7 Modeling the Impact of Tailings and Waste Rock Disposal on the
           Fly River System
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      Sediment transport modeling has been used as a predictive tool at the Ok Tedi from the earliest investigations to the present. A wide range of sedimentary processes occur, from debris flows in the upper reaches to silt-dominated fluvial transport in the lower reaches. No single model or approach is suitable for such a variety of processes, and a wide range of techniques have been used; gradually increasing sophistication according to data availability has improved. This chapter describes some of the main approaches and then concentrates on results from a recent set of modeling. It shows how models have been calibrated and validated and then predicts likely patterns of deposition and water surface profile change over the next 60 years.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 8 Floodplain Inundation Modeling and Forecasting for the Middle
           Fly
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      This chapter describes how water levels are likely to increase on the Middle Fly in response to deposition of mine waste over the next 40 years or so. It also shows where floodplain inundation will increase and presents maps of flooded areas prior to mining, at mine closure and in 2050. The predictions are based on results from the 2003 sediment modeling study (Pickup and Cui, this volume) and an unsteady flow hydraulic model of the floodplain. The model incorporates backwater effects from the Strickland, downstream attenuation of flood waves and the influence of flows to and from off-river water bodies on the floodplain. The hydraulic model uses the unsteady version of the HEC-RAS model. Water surface profiles calculated in HEC-RAS are used with the GRADFLOW model to calculate the extent and location of floodplain inundation throughout the length of the Middle Fly. The floodplain inundation model uses topographic data collected as part of the Shuttle Radar Topography Mission (SRTM) in 2000. The data are not accurate enough for flood modeling and have been corrected using observed flood extents and water surface profiles from Middle Fly gauging stations. The flood extents were mapped from a variety of satellite images. Hydraulic model results show that increases in water level due to deposition of mine waste gradually pass down the river system and develop a fairly uniform water surface slope. This is a normal response to an increase in sediment load. Maps of the extent of inundation show that most of the floodplain will eventually be affected and large areas will experience a substantial increase in inundation frequency. More frequent flooding will also extend up floodplain tributaries but this effect will be limited because the floodplain is confined by Pleistocene terraces. Much of the impact will occur long after mine closure.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 9 Biogeochemistry of Copper in the Fly River
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      The factors affecting the distribution and mobility of copper in the Fly River system are described. Once immersed in river water, mine-derived particulates are subject to a number of processes which may result in release of copper into solution. Copper sulfides present in the mine-derived sediments are highly insoluble in river water, but undergo chemical oxidation during processing at the mill and bacterially mediated oxidation in the water column which increases the reactivity of the particulate copper. Solution chemistry is also important with the highest release of copper being found at low pH. Over the pH range encountered in the river system (typically 7.0–8.2), complexation of copper by natural organic matter resulting in the formation of soluble copper–organic matter complexes is an important factor governing the dissolved copper concentrations in the river system. When the river floods, a substantial proportion of mine-derived sediments are transported laterally onto the floodplain and into off-river water bodies. Under wet conditions, these environments tend to act as sinks for copper with very little release of copper into solution. However, drying of deposited mine-derived sediments, as occurs under dry climatic conditions (e.g., El Niño), followed by wetting is likely to cause widespread release of copper into solution. In the Fly River Estuary, particulate copper concentrations in suspended sediments rapidly drop to background concentrations (ca. 42μg/g) owing to dilution and mixing with the large pool of natural suspended sediments. Dissolved copper concentrations decrease by ca. 50% in the low-salinity zone of the estuary owing to a combination of precipitation and adsorption reactions which remove copper from solution. Based on the processes identified, a process-based geochemical fate/transport model was developed to predict dissolved copper concentrations in the river system over mine life and beyond. The model predicts that it will take at least 40 years post mining for the river system to return to pre-mine copper concentrations. This is because of the large amount of copper-contaminated sediments stored in the river system and on the floodplain which will continue to be a source of soluble copper to the system for decades.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 10 Speciation, Bioavailability and Toxicity of Copper in the Fly
           River System
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      Discharge of mine tailings into the Fly River since 1984 has resulted in elevated concentrations of particulate and dissolved copper, with documented detrimental impacts on fish populations and other aquatic biota. This chapter reviews recent monitoring of copper and toxicity in the Fly River, assesses recent trends in copper bioavailability, and highlights data gaps in our current understanding of copper effects on biota in the Fly River. While in situ monitoring of fish abundance and species diversity gives an indication of the impact of multiple stressors on fish populations, it does not identify the impact of dissolved copper alone. The most useful data for assessing the effects of dissolved copper come from laboratory-based toxicity tests (bioassays) conducted on aquatic species representative of those found in the Fly River. Several bioassays using copper-sensitive bacteria and microalgae isolated from nearby reference sites, have been used over the past 10 years to monitor copper toxicity in the Fly River system, in conjunction with chemical analyses of dissolved copper, labile copper, and copper-complexing capacity. These bioassays respond to concentrations of biologically available copper in the low micrograms per liter range, and were intended to act as an early warning of copper toxicity to aquatic organisms resident in the Fly River system. Copper speciation, i.e., the chemical forms of copper in natural waters over the pH range 7–8, typical of the Fly River system, is dominated by complexation by natural organic matter. However, in systems receiving elevated inputs of dissolved copper, the complexing capacity of natural organic matter may be exceeded, leading to an increase in the amount of inorganic copper in solution. It is now well established that inorganic copper species, such as the free copper ion or weak or labile complexes that are able to dissociate at the organism–water interface, are more bioavailable than copper in strong or inert complexes or adsorbed to colloidal and particulate matter. The monitoring data indicate that both dissolved copper concentrations and copper-complexing capacities in the Upper and Middle Fly River have remained relatively constant since 1996. However, in the Middle Fly, labile copper concentrations appear to be increasing. The reason for this increase is unknown, but may be due either to inputs of more reactive copper from a change in mining throughput and/or the dredge stockpiles at Bige, or to vegetation dieback on the floodplain and consequent reduced organic matter input or changes in organic matter composition, which in turn influences copper speciation. The frequency of algal growth inhibition has also increased since 1996. Early bioassays with a green alga in 1995 found no toxicity in any of the 10 water samples from sites on the Fly River, despite the fact that they contained between 0.5 and 13μg/L of dissolved copper, well above the lowest observed effect concentration (LOEC) of 2.5μgCu/L for this alga. More bioassays at sites on the Middle Fly River have shown an increase in the frequency of algal growth inhibition, together with bacterial inhibition, corresponding to an increase in labile copper concentrations. The magnitude of algal inhibition, however, has not significantly increased and there is no significant correlation between the amount of algal inhibition and labile copper concentrations in the river. Addition of the metal chelating agent EDTA to water samples consistently removed the observed toxicity in both the algal and bacterial bioassays. This indicates that the toxic effects are likely to be related to the presence of metal contaminants. Of the dissolved metals measured in river waters since 2002, only aluminum and lead exceeded guideline trigger values (ANZECC/ARMCANZ, 2000) on several occasions. Comparison of monitoring data for labile copper to literature data on the sensitivities of freshwater biota to copper shows that algae, invertebrates, insects, and fish are all at risk of chronic effects from copper in the Fly River system. At current labile copper concentrations, chronic effects of copper resulting from long-term exposure to elevated bioavailable copper concentrations may be expected in 50–80% of freshwater species. Any further increases in labile copper in the river may result in chronic toxicity to the majority of freshwater species. In addition, the potential interactive effects of acidification from acid rock drainage (ARD) and metal toxicity are only now being assessed.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 11 The Biology of Barramundi (Lates calcarifer) in the Fly River
           System
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      Barramundi (Lates calcarifer) is a large species of Centropomidae that occurs in coastal waters, estuaries, and freshwaters from western India, around Sri Lanka to the Bay of Bengal, and through the whole of Southeast Asia to Papua New Guinea and northern Australia. In New Guinea it occurs on the coast and inland in most rivers in the south of the country, with the largest populations in the Fly River. Throughout its range it supports extensive commercial, aquacultural, and recreational fisheries, and in Papua New Guinea it is the most economically important species in the artisanal fisheries of Western Province. Recent genetic research shows that, unlike the situation in northern Australia where there are multiple small genetic stocks of Barramundi, there is just one large stock of Barramundi living in the Fly River and associated coastal waters. This stock extends into Irian Jaya (West Papua), thereby constituting a cross-border resource, but differs from a small isolated stock of Barramundi found in the far east of Papua New Guinea. It has a complex life history and is a protandrous hermaphrodite (starts life as a male and changes to female). A complete reorganization of gonad structure and function takes place after sex inversion, probably under the influence of hormones. L. calcarifer spawn as males for 3–4 years before sex inversion. The fecundity of L. calcarifer is among the highest of any teleost fish, with estimates of from 0.6 to 2.3×106 eggskg−1 of body weight. Large female Barramundi move to the coastal spawning grounds near Sigabaduru (west of Daru) during the late dry season (September–October) when gonad maturation takes place in estuarine waters (salinities of 28–36‰). Spawning takes place in the sea, and between October and February, as the wet season progresses, there is a tidal-based monthly cycle of spawning, with larvae moving into shallow coastal areas and backswamps shortly after hatching at around 5.0-mm long, usually on the spring high tides. Spawning at this time ensures that the juveniles can enter sheltered coastal areas, flooded backswamps, or floodplains and remain in these areas until they dry up during the early part of the dry season. They rapidly become the dominant predators of other fish larvae and crustaceans in this habitat. Juvenile Barramundi leave these habitats and disperse eastward (and westward) along the coast at about 6 months of age and at a length of about 200mm. Some stay in coastal waters while the majority migrate into the lower Fly River and continue to move upstream, reaching the middle Fly River, the Strickland River, and Lake Murray where they grow to become adults. These adults do not, however, follow a regular annual migration to the sea as they do in Australia, and many fish only visit the sea once during their lives, with some individuals remaining upriver for extended periods. During flood periods many Barramundi move into off-river water bodies, particularly oxbow lakes, where there is an abundance of crustaceans and small fish, such as Fly River Herring (Nematalosa spp.), that form the bulk of their diet. Barramundi have long been subjected to heavy fishing pressure, both artisanal and commercial, in the Fly River and along the coast of Western Province. Overexploitation by commercial fisheries in the 1980s is thought to have contributed to a massive decline in numbers, which is only now being reversed with the help of enlightened management regulations based upon a thorough understanding of the life cycle and biology of the species.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 12 Use of Changes in Fish Assemblages in the Fly River System,
           Papua New Guinea, to Assess Effects of the Ok Tedi Copper Mine
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      Biological monitoring of fishes in the Fly River system in Papua New Guinea has been carried out to assess the effects of mine wastes from the Ok Tedi copper mine. Since the commencement of monitoring operations in 1983, 86 fish species representing 32 families have been recorded from sites in the main river channel, and 66 species from 33 families in floodplain habitats (oxbow lakes, blocked valley lakes, and seasonally inundated grassed floodplain). Catfish in the families Ariidae and Plotosidae were the taxonomically most diverse groups overall, although Nematolosa herrings were the most numerically abundant species, forming 37 and 66%, respectively, of fish caught from riverine and floodplain sites. Barramundi, Lates calcarifer, had the greatest biomass, constituting over 30% of the overall weight taken. Fish catch showed considerable change over time. At riverine sites, there were highly significant declines in biomass over time, ranging from 57% decline at Obo (1987–2002) to 92% decline in the Ok Tedi at Ningerum (1983–1996). The greatest declines in biomass were recorded from sites closest to the mine within the Ok Tedi, although reductions of up to 79% were also recorded at sites in the middle Fly. Within the Fly River, the extent of declines in biomass decreased with increasing distance from the mine. Changes in assemblage structure were also recorded at riverine sites, with a decline in frequency of occurrence of some species and in some cases, loss of species from parts of the system. The main causes of fish declines in riverine reaches, including both mine-related and non-mine-related factors, are discussed. The loss of fish habitat through increased river bed aggradation, due to the input of mined waste rock and tailings, is likely to be the main causal factor. However, other mine-related factors, such as elevated levels of suspended sediment, and dissolved and particulate copper, and non-mine-related factors, such as introduced species and artisanal fishing, may also contribute to declining fish catches. Reduced catches have also been recorded from a number of floodplain sites over the sampling period, although changes in fish assemblages at lakes Pangua, Bosset, and Daviumbu do not appear to be mine related, but are probably associated with natural climatic factors, particularly El Niño-La Niña drought-flood cycles and algal blooms. Fish populations were shown to recover only slowly in shallow lagoons affected by severe drought conditions, with extensive mats of floating grasses likely hindering fish recolonization. Fish stocks in a lake affected by an algal bloom recovered more quickly than stocks in lakes affected by drought. Recent analysis suggests reductions recorded from floodplain sites in close proximity to the Ok Tedi may be mine related (viz. OXB06). Suggested causes relate to increased flooding and forest die-back due to riverbed aggradation, which result in elevated turbidity, infilling of oxbows, and elevated dissolved metals. Introduced species and increased commercial and artisanal fishing may also be affecting floodplain assemblages.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 13 Effects of Mine-Derived River Bed Aggradation on Fish Habitat
           of the Fly River, Papua New Guinea
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      Monitoring of the effects of the Ok Tedi Mine on the Fly River system has shown that the discharge of waste rock and tailings into the river has resulted in elevated sediment loads, increased particulate and dissolved copper levels, aggradation of the river bed, increased frequency and duration of floodplain inundation, and dieback of floodplain forest. Biological monitoring has reported significant and continuing declines in fish catch in the Fly River downstream of the mine. Given that previous studies ruled out acute toxic effects from metals, it was hypothesized that major cause of the declines in fish catch and diversity was loss of fish habitat due to river-bed aggradation. In November 2002, field measurement and hydrographic survey were used to quantify fish habitat at impacted and control reaches to assess habitat loss in relation to aggradation. Fish habitat ‘availability’ was quantified using 55 measured and derived parameters at 19 reaches, ranging in aggradation for 0–4.5m. Habitat availability was found to decline with increasing bed aggradation. Attributes of fish habitat that consistently demonstrated a negative relationship to aggradation included number and size of deep backwaters, amount and complexity of large woody debris (snags), amount of cover for fish close to the banks (i.e., trailing vegetation, root mats, undercuts, riparian canopy), heterogeneity of the banks and river bed, and combinations of these variables when weighted by depth and water velocity. Results support the hypothesis that aggradation reduces fish habitat availability, which is likely a cause of the declines in fish catch in the lower Ok Tedi and upper Middle Fly River. The impact on fish habitat appears to be a physical process, driven by the load of waste rock and tailings deposited in the river system. As such, it may be possible to predict future effects on fish habitat by modeling sediment delivery, sediment transport, and associated aggradation/degradation of the river bed.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 14 Insects of the Fly River System
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      Like much of New Guinea, the Fly River region is exceedingly rich in insect life. The lowlands and foothills support a high species diversity while the higher mountains have somewhat fewer numbers but nevertheless a very interesting and different fauna. However, the insect fauna remains largely unstudied and many new species await discovery. The four most important collections of Fly River insects are those assembled by L. D’Albertis in the 1870s (Civico Museo di Genova), W. W. Froggatt in 1885 (Australian Museum and Australian National Insect Collection), W. W. Brandt in 1957 (Bishop Museum and ANIC), and R. B. Lachlan 1991–2000 (ANIC, AM). More than 220 species of butterflies and 66 species of hawk moths are known, although the total number of moth species probably numbers thousands. Several hundred species of beetles have been recorded (including almost 100 species of weevils); the total number of beetle species can also be expected to number thousands. Cicadas have also been well known but only from mountain areas; the total number of species exceeds 30. Other insects are less well known. Some Diptera (flies and mosquitoes) have been studied, but other insect orders, including Odonata (dragonflies) and Hymenoptera (bees, wasps, and ants), remain virtually unstudied.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 15 Vegetation of the Ok Tedi–Fly River System
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      This chapter provides an overview of the major vegetation associations, including structure, characteristics, and species composition. Relevance of vegetation to regional ecosystems and to the human communities within the Fly River Basin (the Basin) is discussed. The pivotal role of vegetation in stabilizing and reestablishing damaged ecosystems is also presented. The flora of the Fly River Basin represents a mix of taxa representing a high degree of endemism, particularly in the high-altitude catchments, and influences from the Indo-Malaysian Floral Region. Vegetation associations of the Fly River Basin range from mid-montane forests at higher elevations in the headwaters region through foothill forests, lowland rainforests, extensive open grassed wetland floodplains and semiaquatic woodlands, and unique swamp forests subjected to seasonal flooding along the Middle Fly and upper South Fly regions, giving way to Eucalyptus and open grassland savannahs around and west of Suki, and further south to the Wipim area. In the Middle Fly and upper South Fly below Everill Junction, where the Strickland River joins the Fly River, small, scattered patches are all that remain of the swamp forests and woodlands. Further downstream toward Sturt Island and Tapila are the most luxuriant remaining tropical rainforests with small patchy savannah associations. Enormous sago communities once characterized parts of the lower Ok Tedi, the Middle Fly, and the upper South Fly, but almost all of these are gone due to mine-related forest dieback, the El Nino drought of 1997–1998, and the La Nina floods of 1999–2001. Mangrove communities in the Fly River estuary form a distinct and important association in tidal and brackish waters. Members of the Rhizophoraceae, Sonneratiaceae, and Nypa form the predominant species. The middle and upper regions of the estuary are characterized by two Rhizophoraceae species: Bruguiera parviflora and Rhizophora apiculata, and Sonneratia lanceolata reflecting the strong freshwater and low-salinity regime present. Nypa fruticans associations are also characteristic features of many islands in the Kiwai Wabada area of the delta where they form thick impenetrable pure stands and indicate strong freshwater influence. Toward the seaward margin, several higher salinity tolerant key species are found, including Avicennia marina, Rhizophora stylosa, Ceriops spp., Aegialitis annulata, and Sonneratia alba. In contrast, S. lanceolata is the first mangrove in the uppermost, inland regions of the estuary, extending to just upstream of Suki Creek. The presence of S. lanceolata more than 200-km upstream indicates the powerful influence of the tidal surge enhanced by the strong tidal bores as they push salt water up the Fly River against the immense downstream force of the freshwater flow.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 16 Fauna and Food Webs of the Fly River Basin
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      The fauna of the Fly River Basin is diverse and distinctive. The forests of New Guinea harbor no monkeys, large mammalian predators, or mammalian herbivores, such as those which occur in the rain forests of Asia, Africa, and the Americas. Many of the species present are endemic to New Guinea or small rain forest areas remaining in northern Australia. The basic structure of animal communities and food web organization of ecosystems in the Basin is similar to forest food webs elsewhere; however, interspecies relationships have been dictated by New Guinea's close association with Australia and prolonged isolation from neighboring land masses. Though humans have inhabited New Guinea for more than 50,000 years, it is only during the past century that incursions by outsiders for mining, harvesting timber, and other exploitative activities have become the primary influences on the environment. Recent mining impacts in upper portions of the Fly River Basin have resulted in forest dieback over large areas of the Basin. Riverine disposal of waste material from the Ok Tedi Mine has severely impacted downstream environments and in particular, the lower Ok Tedi and Middle Fly River Basin. Virtually no mature forests remain in the floodplain of the Lower Ok Tedi or the upper Middle Fly River Basin. Consequently, the distribution and abundance of many forest-dwelling animal species within the Basin have shrunk drastically over the past two decades. Long-term effects on the fauna of the Basin and the human communities that depend on them continue to be major concerns.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 17 Development of Aquatic Food Web Models for the Fly River, Papua
           New Guinea, and their Application in Assessing Impacts of the Ok Tedi Mine
           
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 9

      Understanding ecological linkages of species to their food sources and predators is vital to the understanding of interactions amongst species. Food webs are a useful means to summarize the often complex interactions and provide insights into how changes to one component can affect other components (i.e. top–down versus bottom–up responses). Such food webs are equally valuable for studying unmodified systems, as well as those affected by anthropogenic activities. An example of the latter is the effects of the Ok Tedi copper mine on the Fly River, Papua New Guinea. The mine uses riverine disposal of waste rock and tailings, and from early mine life, food webs were seen as a useful tool for understanding the effects of the mine on the ecology of the river. This paper describes the progressive development of aquatic food webs for the Fly River, from preliminary models developed with minimal data prior to mine construction, to progressively more accurate and complex models which include additional species and greater knowledge of the various components of the system. The paper notes the general accuracy of early attempts of ecologists using little data, but basing their interpretation on experience and sensible assumptions. It also presents the better-informed models subsequently developed using extensive data. Finally, the paper details more recent investigations using stable isotopes of carbon and nitrogen to elucidate energy flow through the aquatic ecosystem, and how this approach has advanced the understanding of current and possible future impacts of the mine on the aquatic system.

      PubDate: 2012-12-15T09:31:08Z
       
  • Antarctic Climate Evolution
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 8



      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 1 Antarctic Climate Evolution
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 8

      Central to the understanding of global environmental change is an appreciation of how the Antarctic Ice Sheet interacts with climate. To comprehend the processes involved one must look into the geological record for evidence of past changes. For several decades international efforts have been made to determine the glacial and climate history of Antarctica and the Southern Ocean. Much of this information derives from studies of sedimentary sequences drilled in and around the continent. In addition, there have been numerous terrestrial geological expeditions to the mountains exposed above the ice surface usually close to the margin of the ice sheet. Holistic interpretation of these data is now being made, and hypotheses on the size and timing of past changes in Antarctica are being developed. In 2004, the Scientific Committee on Antarctic Research (SCAR) commissioned a scientific research programme on Antarctic Climate Evolution (ACE) to quantify the glacial and climate history of Antarctica. This book is a result of that programme, and documents, for the first time, the state of knowledge concerning the ice and climate evolution of the Antarctic continent and its surrounding seas through the Cenozoic era.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 2 The International Polar Years: A History of Developments in
           Antarctic Climate Evolution
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 8

      The first three International Polar Years (IPYs; 1882–1883, 1932–1933, 1957–1958) were major periods of intense multidisciplinary polar research, bringing significant new insights into global processes and laying the foundation of knowledge of the polar regions for future decades. The fourth IPY (2007–2009) continues the tradition of international science years and is one of the most ambitious internationally coordinated scientific research programmes ever attempted. In contrast to the three previous IPYs, the new IPY incorporates research within social science and its interface with the natural sciences. The new IPY also includes a wide range of education and outreach activities, and a commitment to excite and train the next generation of polar researchers. We discuss briefly the history of the IPYs, and their contribution to comprehending Antarctic Climate Evolution.

      PubDate: 2012-12-15T09:31:08Z
       
  • Chapter 3 A History of Antarctic Cenozoic Glaciation – View from the
           Margin
    • Abstract: 2008
      Publication year: 2008
      Source:Developments in Earth and Environmental Sciences, Volume 8

      The scale and antiquity of the Antarctic Ice Sheet was sensed from the time of earliest exploration a century ago. However, significant advances in scientific thinking, along with logistics and technology for gathering data from the continent itself, were required before a clear and consistent framework for ice-sheet history and behaviour could develop and this has emerged only in the last few years. The main features of the present ice sheet were established by over-snow traverses during and following the International Geophysical Year (1957–1958), but the timing and circumstances of its origin remained uncertain. Geological records of post-Jurassic time were largely buried under the ice or the sea floor around the Antarctic margin, though a few radiometric ages from the new K–Ar dating indicated Antarctic glaciation was likely older than the Northern Hemisphere ice ages of the Quaternary Period. New post-World War II techniques in offshore surveying with marine geophysics and ship-based drilling were first applied to the Antarctic margin in the early 1970s, and were immediately productive. The Antarctic continental shelf was found to be underlain by sedimentary basins with the promise of ice-sheet history, and in early 1973, cores from Leg 28 of the Deep Sea Drilling Project (DSDP) in the Ross Sea provided the first physical record of Antarctic glaciation extending back to Oligocene times. DSDP Leg 29 drilled in the Southern Ocean for deep-sea cores from the whole Cenozoic Era, yielding the first set of oxygen isotopic ratios (δ18O) from benthic calcareous microfossils, and the first estimates of ice volume. These indicated a two-stage ice-sheet history (cooling and some ice at 34Ma, and persistent ice from 14Ma – time-scale of Berggren et al., 1995). About the same time, the Dry Valleys Drilling Project (DVDP) was launched to recover onshore records of Antarctic Cenozoic climate history, and exploratory drilling from fast ice offshore soon followed. Cores from the Ocean Drilling Program in the 1980s from the Prydz Bay Shelf and the Kerguelen Plateau established the timing of the first continental ice sheet at 34Ma. In the same period, deep continuous coring from sea ice in McMurdo Sound developed from DVDP technology succeeded in providing new detail for its subsequent history. Core recovery at ∼98% yielded lithological evidence of ice margin and sea level fluctuations implied by deep-sea isotope records. Further drilling with improved chronology in the 1990s yielded cores confirming ice margin and sea level changes on Milankovitch frequencies and on a scale of 10–40m of sea level equivalent. Micropalaeontological and geochemical evidence pointed to a slight cooling from a coastal cold temperate climate, with beech forests during interglacial times. Subsequent development of ice-sheet modelling has indicated that most of the cooling that initiated ice-sheet glaciation was the consequence of a fall in atmospheric CO2 levels below a critical threshold, allowing ice sheets to form that were highly sensitive to orbital forcing. This claim has been supported by recent work on CO2 proxies and indicators of a shift in carbonate compensation depth in deep-sea sediments. Since the first measurements in the 1970s, deep-sea isotopic measurements have implied a significant increase in Antarctic ice volume at around 14Ma that persisted to the present day. However, in the mid-1980s, marine diatoms in glacial deposits in the Transantarctic Mountains suggested periods in Pliocene times when seas invaded the East Antarctic interior, implying dynamic Antarctic Ice Sheets until Quaternary times. Evidence of continued cold in the mountains over the last 14Ma, glaciological problems with the proposed over-riding scenario, lack of a signal in the deep-sea isotope record for the loss of most Antarctic ice in Pliocene times and possible alternative atmospheric sources for diatoms has shifted the weight of evidence in favour of persistent ice in the east Antarctic interior. However, coastal outcrops in Prydz Bay and a recent deep core from beneath the McMurdo Ice Shelf have shown that in the globally warmer Pliocene, notably around 3–5Ma, seas around the Antarctic margin were several degrees warmer. Indeed, recent drill cores suggest that the Ross Embayment and perhaps also most of the West Antarctic interior were periodically ice-free in these times. Three decades ago, the Antarctic Ice Sheet was seen as a long-standing feature of the Earth with its origins in early Cenozoic times and its permanency assured by mid-Miocene cooling. Research in the last decade from geological drilling and glaciological remote sensing, supported by ice sheet and climate modelling, indicates the ice sheet is in fact quite responsive to changes in the global climate system, whether natural or human-induced, though at different rates in different sectors. Recent developments in both science and technology outlined here provide opportunities for projecting realistic scenarios for future ice-sheet response on human time scales.

      PubDate: 2012-12-15T09:31:08Z
       
 
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