Geochemistry of Epigenesis

Monographs in Geoscience General Editor: Rhodes W. Fairbridge

Department of Geology, Columbia University, New York City

B. B. Zvyagin Electron-Diffraction Analysis of Clay Mineral Structures-l 967

E. I. Parkhomenko Electrical Properties of Rocks-1967

L. M. Lebedev Metacolloids in Endogenic Deposits-l 967

A. I. Perel'man The Geochemistry of Epigenesis-l 967

In preparation:

A. S. Povarennykh Crystal-Chemical Classification of Mineral Species

S. I. Lefond Handbook of World Salt Resources

Geochemistry of Epigenesis

Aleksandr I. Perel'man Department of Geochemistry Institute of Ore Deposits, Petrography, and Mineralogy Academy of Sciences of the USSR, Moscow

Translated from Russian by

N. N. Kohanowski Department of Geology University of North Dakota, Grand Forks

With a Foreword by

Rhodes W. Fairbridge

<±> Springer Science+Business Media, LLC 1967

Aleksandr ll'ich Perel'man, senior scientist in the Department of Geo­chemistry at the Institute of Ore Deposits, Petrography, and Mineralogy of the Academy of Sciences of the USSR in Moscow, was born in Moscow in 1916. In 1938, he was graduated from Moscow State University, as a spe­cialist in topology, and received his doctorate in mineralogy in 1954. Perel'man is the author of seven books, many of which have been translated into Chinese, Hungarian, Bulgarian, and English, and 135 scientific papers. His research concerns mainly the geochemistry of landscapes and the geo­chemistry of epigenetic processes. In 1966, he was awarded a gold medal by the Geographical Society of the USSR for his work on the geochemistry of landscapes.

The original Russian edition was published by Nedra Press, Moscow, in 1965.

AAeKCQHap H.1bU'i flepeAbMaH

FEOXJ1MJ15J ClnJ1rEHETH'IECK.J1X npOLI.ECCOB

GEOKHIMIY A EPIGENETICHESKIKH PROTSESSOV

GEOCHEMISTRY OF EPIGENESIS

Library of Congress Catalog Card Number 65-25241

ISBN 978-1-4899-6235-5 ISBN 978-1-4899-6497-7 (eBook) DOI 10.1007/978-1-4899-6497-7

©1967 Springer Science+Business Media New York

Originally published by Plenum Press in 1967.

Softcover reprint of the hardcover 1st edition 1967 All rights reserved

No part of this publication may be reproduced in any form without written permission from the publisher

Dedicated to Alexander A. Saukov An outstanding Russian geochemist

Foreword

In its classical sense "epigenesis" refers to all geological processes originating at or near the surface of the earth. It thus embraces all those phenomena which we associate with the land­scape; Perel'man has already written extensively on this subject. The landscape, in the physical sense, is controlled by the interac­tion of exogenic and endogenic agencies-on the one hand, the atmo­sphere, the wind, the rain, and other components of the weather, the forces of running water and the planetary controls of gravitational and tidal nature; and on the other hand the materials of the earth's crust, from sediments to metamorphic rocks and igneous materials from deep endogenic sources.

In practical terms the epigene region involves the products of weathering, the soils, the transported material, the colluvium of hillsides, and the alluvium of stream valleys. It involves those landforms that are products of the erosional sculpturing of the landscape, as well as those that result from accumulation, such as glacial moraines and desert sand dunes. The science of geomor­phology is gradually beginning to evolve from a passive cataloging of scenery and its deduced causes (in the Davisian sense) into a vigorous study of dynamic processes. These are partly geophysical, in the sense of hydraulics and mechanical studies, and partly geo­chemical. It is in regard to the latter that we owe a considerable debt to Perel'man and others of the Soviet school of geochemists, who are bringing a great deal of new and carefully analyzed data to bear to help explain the multitude of problems of the epigene zone.

Generally speaking, this is the zone of rainwater, well oxy­genated, high in CO2, and of low pH. At the ground surface, in the soil, in the groundwater, and deeper in the artesian circulation,

vii

viii FOREWORD

the former rainwater goes through many changes: the pH may swing over to the high alkaline range, and the Eh to the reducing field. In regions of ore deposits it plays a critical role in trans­porting ions downwards, forming "supergene deposits." Perel'man finds this term useful in general application, so we have a "super­gene zone." Those minerals concentrated by the surface waters are, in contrast, the "epigene deposits." The former are thus intimately related to the latter.

Seen from the viewpoint of the volution of sediments which begin their diagenetic evolution with syndiagenesis, engendered by the reactions appropriate to their site of origin, the end-stage in the evolution of a sedimentary rock is what this writer has called "epi­diagenesis." In both the earliest and latest stage the environmental chemistry is dominated by its reactions with the biosphere. Thus, Perel'man in Chapter 1 begins with a discussion of "living matter." This should make salutary reading for some of our geologists who do not see the role of biology in our science.

New York City August, 1967

Rhodes W. Fairbridge

Preface

Identical chemical phenomena are often observed in entirely unrelated rocks. For example, the weathering of feldspars and their subsequent conversion to kaolin and gypsum takes place in all types of rocks. We can thus speak of the geochemical types of the epigenetic processes which are common to all the formations of the supergene zone. The conclusion is inescapable that such epigenetic processes should be considered as a specialized group of phenomena. The methods of geochemistry lend themselves to the study of such processes.

A review of such epigenetic processes constitutes the subject of this book, which has grown about the nucleus of the lectures delivered by the author at the Institute of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM) of the Academy of Sciences of the USSR.

The geochemical approach to the study of epigenetic processes is indispensable to the solution of both theoretical and practical problems, such as geochemical exploration and theories of exogenous ore formation.

Some of the concepts treated in this book have been developed by the author during his investigations in Central Asia and other parts of the Soviet Union. The existing literature has been freely drawn upon.

In preparing this book for publication, the author had in mind the needs of geologists, who, working in various remote regions, are going to use geochemical methods of investigation, particularly methods for finding ores. To be useful to such persons, the material had to be presented in a systematic way and so some material had to be included which does not represent anything new.

The first edition of this book was published in 1961. This second edition was revised and enlarged. Valuable suggestions

ix

x PREFACE

were made by Dr. A. A. Beus, Director of the IGEM, and by S. G. Batulin, O. I. Zelenova, and N. A. Volukhovykh. S. G. Baroyanits did a great deal of the editing. The author is grateful to them all.

A. I. Perel'man

Contents

Ir1troduction • . • • . • • . • . • . • . . • . • . . . . . . . . . . . . . . . 1

Chapter 1. Geochemical Role of Living Matter (Biogenic Migration). • . • . . • . . . . . . . . . • . . • • • . • . . . • . . . . . 5

Formation of Living Matter. • • . • . • . . • • . . . . . . . . . 5 Decomposition of Organic Matter. . . . . . . . . . . . . . 10 Biologic Cycle of Chemical Elements . . . . . . . . . . . . . 12 Living Matter in Geologic History . . . . . . . . . . . . . . . 14

Chapter 2. Geochemical Parameters of Elements Which Condition Their Physical and Chemical Migration . . . . .. 19

Chemical Bonds and Crystal Lattices of Minerals. . . . . 19 Valence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Dimensions of Ions and Atoms. . . . . . . . . . . . . . . . . . 27 Isomorphism. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 28 Ionic Potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Solubility. . . . . . . • . • . . . . . . . . . . . . . . . . . . . . .. 31

Chapter 3. Law of Mass Action in Geochemistry. . . • . . . . . 35 Dissociation Constant and pH of Water . . . • • . . . • . • . 37 Dissociation Constants of Acids. . . • . • • • • • . • . . • . . 41 Complex Ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Undissociated Molecules. • • • • . . • • • . • • • • . • . . . • • 47 Solubility Product. • • • . . • • . • • • • • . . . • . . • • • . . • 48 Ionization Power of Natural Waters • • • • . . • • • • • . . • 52 Concentration of Elements in Natural Waters and Its

Significance to the Formation of Minerals. . • • • • • • • 54

Chapter 4. Analysis of Energy Involved in Supergene Migra-tion • • . • . . . . . • . . . • . . • . . . . . . . • . . . . . . . . . . . . 57

Chemical Affinity 60

xi

xii CONTENTS

Oxidation-Reduction Reactions . • . . • . . . . . . . . • • . . 75 Electrochemical Leaching of Sulfide Ores . . . . . . . . . . 80 Stability Ranges of Minerals and Chemical Compounds. 81 LeChatelier Principle • . . . . . . . . . . 85 Fersman's Geoenergetic Theory. . . . 87 Principle of Retardation of Reactions. 90

Chapter 5. Migration of Colloids . . . . . . . 95 Occurrence of Colloids in the Supergene Zone 95 Migration of Substances in the Colloidal State. 96 Sorption. . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Principal Groups of Colloidal Minerals. . . . . . 100

Chapter 6. Occurrence of Chemical Elements in the Super-gene Zone. . . . . . . . . . . . . . . . . . . . . . . . . 105

Chapter 7. Natural Media of the Supergene Zone. 111 Soil. . . . . . . . . . . . . . . . . . . . 111 Weathered Crust •.•....... 114 Surface and Ground Waters. . . . 119 Geochemical Landscapes • . . . . • . • . . • . . . 119 Water-Bearing Strata of the Catagenetic Subzone • . . .• 120 Weathering and Cementation. . • . • • . • • . . • . . . • • •. 125 Epigenetic Zoning. . • • • . • • • • • • • • . • • • . • • . • . .• 127

Chapter 8. Factors in the Development of Media in the Supergene Zone • . • • . . • . . . . .. ....... 129

Climate. • . . . . . . 129 Zoning. . . • . . . . . . . . . 131 Geologic Structure. . . . . 137

Chapter 9. Classification of the Epigenetic Processes Oper-ating in the Supergene Zone. . . . 143

Typomorphic Elements ... . . . . . . . . . . . . . . . . . 143 Aeolean and Aqueous Migrants. . . . . . . . . . . . . . . . 146 Intensity of Aqueous Migration of Chemical Elements 148 Classification of the Supergene Processes. 154

Chapter 10. Epigenetic Processes of Oxidation. 159 The Sulfatic Processes. . . . . . . 159 Acid Processes. . . . . . . . . . . . 165 The Neutral Carbonatic Process 168 The Chlor-Sulfatic Process. 171 The Soda Process. . . . . . . . . . 176

CONTENTS xiii

Chapter 11. The Gley Processes of Reduction in Epigenesis. 183

Chapter 12. Epigenetic Processes in Reducing, Sulfidic En-vironments . . . . . . . . . . . . . . • • • • • • . • . • . . . . • • .. 207

The Sulfato-Sulfidic Process. • • • • • • • • • • . • • . • • •. 207 The Oxysalt-Sulfidic Process. • • • • • • • . • • . • • • • •. 208 The Soda-Hydrogen Sulfide Process. . • . • . • . • • • • •• 211

Chapter 13. Geochemical Barriers. • • • • . • • • • • • . • • • •• 213 The Principal Types of Geochemical Barriers. . . • . .. 214 Epigenetic Concentration of Elements During Cementa-

tion (Approximate Calculations) • • . . . • • • . . . • . .• 231

Chapter 14. Development of Epigenetic Processes Through Geologic History. . . . . . . . . . . . . • . . . . . . • . . . . . .. 235

Chapter 15. Conclusions........................ 239 The Uniqueness of Migration. . . . . . . . . . . . . . . . . .. 239 Geochemical Types of Epigenetic Processes in Natural

Media of the Supergene Zone. . . . . . . . . . . . . . . .. 239 The Geochemical Classification of the Natural Media in

the Supergene Zone. . . . . . . . . . . . . . . . . . . . . . .. 240 The Criteria for the Recognition of Epigenetic Proces-

ses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 241 The Geochemical Types of Reducing Environments. . .. 244 The Geochemical Classification of Natural Waters . . .. 244 Vertical Hydrochemical Zoning in Ground Waters. . . .. 246 Supergene and Hydrothermal Processes . . . . . . . . . .. 249 Formation of Mineral Deposits Surrounded by Secondary

Dispersion Haloes . • . . . . . . . . . . . . . . . . . . . . .. 251 Methods of Studying Epigenetic Processes. • • • . . . . .. 253

Bibliography. . . • . • . • • . • . . • . . . • • . . • • . • • . • . . . .. 255

Index. • . • . . . . . . • • . . • . • . . • . . • . . . . . . . . . . . . . .• 265