Material fluxes on the surface of the earth / / Board on Earth Sciences and Resources, Commission on Geosciences, Environment, and Resources, National Research Council

• Pubblicazione: Washington, D.C., : National Academy Press, 1994
• Edizione: 1st ed.
• Descrizione fisica: 1 online resource (184 pages) : illustrations
• Disciplina: 551.3
• Soggetto topico: Sedimentation and deposition; Weathering
• Note generali: Bibliographic Level Mode of Issuance: Monograph
• Nota di bibliografia: Includes bibliographical references and index.
• Nota di contenuto: STUDIES IN GEOPHYSICS -- Copyright -- Studies in Geophysics -- Preface -- Contents -- Overview -- KNOWLEDGE OF THE PRESENT FLUX RATES OF GEOLOGIC MATERIALS -- RATES OF FLUX OF GEOLOGIC MATERIALS DURING THE MOST RECENT GLACIATION AND DEGLACIATION -- VARIABILITY OF SURFICIAL GEOFLUXES -- Temporal Variability -- Spatial Variability -- Rapid Change and Catastrophic Events -- CONCLUSIONS -- Processes in Shallow Water-Shelf Environments -- Distribution of Lithologies at the Surface -- Distribution of Sources and Sinks -- Rates -- Expanded Time Scales for Processes/Fluxes -- Anthropogenic Influence -- REFERENCES -- Background -- 1 Pleistocene-Holocene Fluxes Are Not the Earth's Norm -- ABSTRACT -- RECOGNITION, DEFINITION, AND LENGTH OF THE QUATERNARY AND HOLOCENE -- MASSES OF QUATERNARY AND HOLOCENE SEDIMENT -- PROCESS RATES -- LONG- AND SHORT-TERM APPARENT ACCUMULATION RATES OF QUATERNARY AND HOLOCENE SEDIMENT -- Deep-Sea Sediments -- Marginal Sea Sediments -- Continental Shelves -- Glacial Sediments on Land -- Nonglacial Continental Sediments -- DISCUSSION -- Sediment Cycling -- The Effect of Glacial-Interglacial Alternations -- Increased Tectonic Activity -- CONCLUSION -- ACKNOWLEDGMENTS -- REFERENCES -- 2 Surficial Weathering Fluxes and Their Geochemical Controls -- ABSTRACT -- INTRODUCTION -- GLOBAL AND ZONAL WATER FLOWS -- Surficial Flows and Storage in Lakes -- Residence Times of Zonal Water Discharge -- Residence Times on a Global Scale -- Summary of Water Flows and Residence Times -- WEATHERING FLUX -- A Conceptual Mode -- Weathering Flux Equations -- Mineral Dissolution Rates (R) -- HYDROGEN-ION AND TEMPERATURE DEPENDENCE OF DISSOLUTION RATES -- The pH and Natural Acidity -- Temperature Effects on Dissolution Rates -- WEATHERING AND DISSOLUTION -- NEUTRALIZATION OF ACIDITY BY WEATHERING RELEASES. ; Background-Alkalinity [Alk], Acidity [Acy], CO2, and pH -- SUMMARIZING DISCUSSION -- ACKNOWLEDGMENTS -- REFERENCES -- 3 Global Chemical Weathering on Glacial Time Scales -- INTRODUCTION -- FACTORS THAT INFLUENCE GLOBAL CHEMICAL WEATHERING -- Climate -- Erosional Area -- Rock Types Exposed -- Glacier Weathering and Erosion Processes -- COUPLED CHANGES -- The Climate/Rock Type Connection -- Forest Coverage and Weathering -- Climate and Glacial Sediment Supply -- IMPLICATIONS FOR OCEANIC AND ATMOSPHERIC CHEMISTRY AND CLIMATE -- ACKNOWLEDGMENTS -- REFERENCES -- 4 Origin and Variable Composition of Present Day Riverborne Material -- ABSTRACT -- INTRODUCTION -- ENVIRONMENTAL FACTORS CONTROLLING CHEMISTRY OF WATER AND SUSPENDED MATTER -- DISTRIBUTION OF RIVER WATER QUALITY -- CONTROL AND DISTRIBUTION OF RIVERINE TRANSPORT RATES -- GLOBAL ORIGINS OF RIVERBORNE MATERIAL -- CONCLUSIONS -- ACKNOWLEDGMENTS -- REFERENCES -- 5 Geomorphic/Tectonic Control of Sediment Discharge to the Ocean: The Importance of Small Mountainous Rivers -- ABSTRACT -- INTRODUCTION -- RIVER DATA -- RESULTS -- DISCHARGE OF SEDIMENT BY WORLD RIVERS -- North America -- South America -- Europe -- USSR and Asia Minor -- Africa -- Asia and Oceania -- Australia -- IMPLICATIONS -- Factors Controlling Sediment Discharge -- What Is the Sediment Flux to the Sea? -- Active Versus Passive Margin Rivers -- ACKNOWLEDGMENTS -- REFERENCES -- 6 Glacial to Modern Changes in Global River Fluxes -- ABSTRACT -- INTRODUCTION -- FLUVIAL PALEOHYDROLOGICAL PRINCIPLES -- Regime Changes and Sediment Transport Mechanics -- SWD-PSI Analysis -- FLUVIAL CATACLYSMIC PROCESSES -- REGIONAL PATTERNS -- Europe and North America -- South America -- Africa, Australia, Southern Asia -- FUTURE WORK -- CONCLUSIONS -- ACKNOWLEDGMENTS -- REFERENCES. ; 7 Sediment Fluxes Along High-Latitude Glaciated Continental Margins Northeast Canada and Eastern Greenland -- ABSTRACT -- INTRODUCTION -- OVERALL CONTROLS ON SEDIMENT FLUX -- Processes -- DEGLACIAL TO INTERGLACIAL FIORD/SHELF SEDIMENT FLUX -- East Baffin Island -- The East Greenland Margin -- CONCLUSIONS -- ACKNOWLEDGMENTS -- REFERENCES -- 8 Late Quaternary Flux of Eolian Dust to the Pelagic Ocean -- ABSTRACT -- INTRODUCTION -- THE GEOLOGIC RECORD OF DUST DEPOSITION -- A Note on Methodology -- Geographic Variation in Eolian Fluxes -- The Downcore Record of Quaternary Eolian Deposition -- DISCUSSION -- ACKNOWLEDGMENTS -- REFERENCES -- 9 Particle Fluxes in the Ocean and Implications for Sources and Preservation of Ocean Sediments -- ABSTRACT -- INTRODUCTION -- METHODS -- REFRACTORY ELEMENT RAIN AND BURIAL FLUXES -- BIOGENIC RAIN AND BURIAL FLUXES -- ORGANIC CARBON PRESERVATION -- CALCITE PRESERVATION -- OPAL PRESERVATION -- THE RELATIONSHIP BETWEEN ALUMINOSILICATE AND BIOGENIC RAIN RATES -- INFLUENCE OF THE CONTINENTAL MARGINS -- EOLIAN SOURCES -- CONCLUSIONS -- REFERENCES -- 10 Seafloor Diagenetic Fluxes -- INTRODUCTION -- THE MEASUREMENT OF BENTHIC FLUXES -- EARLY DIAGENESIS AND MODERN OCEANIC CYCLES -- Na, K, and Mg -- C, Ca, and Si -- Spatial Variability in Early Diagenetic Reaction Rates -- The Oxidants for Organic Matter Degradation: O2, N, and S -- EARLY DIAGENETIC FLUXES AND THE SEDIMENTARY RECORD -- Introduction -- Variations in Burial Efficiency in Marine Sediments: CaCO3, SiO2, and Organic Carbon -- CaCO3 -- SiO2 -- Organic Carbon -- Discussion -- A Model Including Transport and Reaction Effects: The Case of Organic Carbon -- CONCLUSIONS -- ACKNOWLEDGMENTS -- REFERENCES -- Index.
• Sommario/riassunto: Understanding the ebb and flow of materials on the earth's surface is vital to comprehending environmental change. We need to differentiate between those that represent a progression of natural events from those that might be human induced. The latter can be managed by changing policies; the former probably cannot. This volume presents what researchers know and do not know about the base (or natural) level of surficial fluxes and their dynamics. Leading experts in the field offer a historical perspective on geofluxes and discuss the cycles of materials on the earth's surface, from weathering processes to the movement of material through the river system and oceans to their deposition. The committee sets research directions in five areas: shallow-water studies, mapping, rates of change, sample dating, and--most critical--understanding whether human influence can exceed the natural variability in geoflux processes. This volume will be important reading for geophysical scientists, researchers, faculty, and students, as well as environmental policymakers.
• Titolo autorizzato: Material fluxes on the surface of the earth
• ISBN: 9786610211555; 9781280211553; 1280211555; 9780309568630; 0309568633; 9780585037127; 0585037124
• Formato: Materiale a stampa
• Livello bibliografico: Monografia
• Lingua di pubblicazione: Inglese
• Record Nr.: 9910973803303321
• Lo trovi qui: Univ. Federico II
• Serie: Studies in geophysics.