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

Format:

Book

Contributor:

National Research Council (U.S.). Board on Earth Sciences and Resources.

Series:

Studies in geophysics.

Studies in geophysics

Language:

English

Subjects (All):

Sedimentation and deposition.

Weathering.

Physical Description:

1 online resource (184 pages) : illustrations

Edition:

1st ed.

Place of Publication:

Washington, D.C. : National Academy Press, 1994.

Language Note:

English

Summary:

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.

Contents:

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

2 Surficial Weathering Fluxes and Their Geochemical Controls

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

3 Global Chemical Weathering on Glacial Time Scales

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

4 Origin and Variable Composition of Present Day Riverborne Material

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

5 Geomorphic/Tectonic Control of Sediment Discharge to the Ocean: The Importance of Small Mountainous Rivers

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

6 Glacial to Modern Changes in Global River Fluxes

FLUVIAL PALEOHYDROLOGICAL PRINCIPLES

Regime Changes and Sediment Transport Mechanics

SWD-PSI Analysis

FLUVIAL CATACLYSMIC PROCESSES

REGIONAL PATTERNS

Europe and North America

Africa, Australia, Southern Asia

FUTURE WORK

REFERENCES.

7 Sediment Fluxes Along High-Latitude Glaciated Continental Margins Northeast Canada and Eastern Greenland

OVERALL CONTROLS ON SEDIMENT FLUX

Processes

DEGLACIAL TO INTERGLACIAL FIORD/SHELF SEDIMENT FLUX

East Baffin Island

The East Greenland Margin

8 Late Quaternary Flux of Eolian Dust to the Pelagic Ocean

THE GEOLOGIC RECORD OF DUST DEPOSITION

A Note on Methodology

Geographic Variation in Eolian Fluxes

The Downcore Record of Quaternary Eolian Deposition

9 Particle Fluxes in the Ocean and Implications for Sources and Preservation of Ocean Sediments

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

10 Seafloor Diagenetic Fluxes

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

Index.

Notes:

Bibliographic Level Mode of Issuance: Monograph

Includes bibliographical references and index.

ISBN:

9786610211555

9781280211553

1280211555

9780309568630

0309568633

9780585037127

0585037124

OCLC:

42854593