A STUDY OF TWO SOILS DERIVED FROM VOLCANIC ASH IN SOUTHWESTERN BRITISH COLUMBIA AND A REVIEW AND DETERMINATION OF ASH DISTRIBUTION IN WESTERN CANADA by JAMES IAN SNEDDON M.Sc. University of British Columbia, 1970 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of Soil Science We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA November, 1973 / In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver 8, Canada // ABSTRACT Four papers are presented in this thesis each one report• ing on studies relating to volcanic ash with special reference to soils. The first paper reviews a) some of the phenomena relating to the ejection and deposition of ash that are important in interpreting the significance of its occurrence, b) the significance of ash layers to workers in the Quaternary, c) the techniques available for the characterization and recognition of tephra, d) the literature on ash deposits in western Canada and compiles the noted occurrences. In addition this paper presents the data from a study to determine the amount of ash retained by soils within and beyond the major areas of deposition indicated in the literature. The presence of ash in soils was found to be widespread though the amounts present may be limited for identification purposes, in some cases. The second paper describes two soils derived from Bridge River volcanic ash and their underlying paleosols and presents selected physical and chemical analyses. The analyses indicate that in the youthful soils studied the physical properties of the ash soils are inherited from the parent material. The colloidal and chemical properties are initially imparted by organic matter with some influence from ash weathering products especially aluminum. Shallow surface additions of volcanic ash iii to soils influence soil properties to varying degrees depending on pedogenic environment and depth of material. The third paper evaluates a number of methods that have been used to identify podzolic B horizons and the influence of surface additions of volcanic ash on the podzolic characteristics of soils. Pyrophosphate, pyrophosphate dithionite, citrate dithionite bicarbonate extractions, phosphate sorption capacity and pH-dependent cation exchange capacity determinations all highlighted the podzol B horizons while acid ammonium oxalate extractions and pH determined in NaF did not. The presence of surface additions of Bridge River ash may influence acid ammonium Oxalate or NaF criteria but it was not found to reduce the value of the other diagnostic criteria examined in this study. The final paper studies the amorphous material and clay mineral characteristics of the two aforementioned soils and examines some of the methods of extraction and isolation of clay materials in soils. All of the chemical treatments applied to the soils were found to result in some dissolution of secondary and primary soil materials. The treatments used to extract amorphous materials indicated that the Si to Al ratios of extracted materials was greater than 2. As this value approaches 2 the formation of allophane and imogolite will take place. This situation is indicated as having taken place in isolated capillaries as evidenced by the limited occurrence of imogolite-like material. Chlorite is the dominant clay mineral in the ash soils and is believed to be the weathering product of primary biotite, horneblende and pyroxene. iv TABLE OF CONTENTS Page INTRODUCTION 1 VOLCANIC ASH, ITS SIGNIFICANCE AND DISTRIBUTION IN WESTERN CANADA .... 2 Introduction 2 The Significance of Ash Layers in Quaternary^ Studies 3 Post Eruption Transportation and Deposition .... 6 Methods of Ash Identification 8 The Sources and Distribution of Quaternary Volcanic Ash in Canada 12 The Presence and Distribution of Ash in Soils ... 31 Conclusions 48 References 49 A STUDY OF TWO SOILS DERIVED FROM VOLCANIC ASH IN SOUTHWEST BRITISH COLUMBIA . » 61 Introduction 61 The Morphology and Environment of Two Volcanic Ash Soils 63 Materials and Methods 74 Results and Discussion 75 Conclus ions 89 References 92 THE PODZOLIC CHARACTERISTICS OF TWO SOILS DERIVED FROM VOLCANIC ASH IN SOUTHWEST BRITISH COLUMBIA 96 Introduction 96 Page Materials and Methods 98 Results and Discussion 100 Conclusions 112 References 115 THE AMORPHOUS AND CRYSTALLINE WEATHERING PRODUCTS OF TWO SOILS DEVELOPED IN VOLCANIC ASH IN SOUTHWEST BRITISH COLUMBIA 118 Introduction 118 Materials and Methods 121 Results and Discussion 124 Conclusions 143 References 145 SUMMARY 148 vi LIST OF TABLES Table Page I-l. Sets of eruptions of Mt. St. Helens .... 16 2. Mean chemical composition of white River ash 21 3. The approximate locations of sites where volcanic ash has been located and references 24 4. Locations of sites where volcanic ash was located and gross composition of the light fractions of three size separations of the non-organic matter fraction 33 II - 1. Climatic records of stations adjacent to the study sites ..... 70 1. Continued 71 2. Selected physical analyses of the study sites 78 3. Selected chemical analyses of the study sites 81 4. Exchange properties of the study sites . 85 III - 1. Ratio of oxalate to pyrophosphate-dithionite to citrate dithionite to 0.1M pyrophos• phate extractable Fe, Al, Si and Mn . 99 2. Percent Fe and Al extracted by four methods and phosphate sorption by three methods on the fine earth fractions of the study sites 102 vii Table Page III - 3. Mn and Si extracted by the four methods used to extract Fe and Al 103 4. Correlation coefficients between the three methods of P sorption, Pi, P2 and P3 and other soil properties at the 1% level of significance in two ash soils and their underlying paleosols 105 4. Continued 106 5. Correlation coefficients between pH- dependent C.E.C. and other soil properties at the 1% level of signifi• cance in two ash soils and their under• lying paleosols 110 6. pH in NaF, pH-dependent C.E.C. and values derived from Fe and Al extractions by oxalate and pyrophosphate in two ash soils and their underlying paleosols . Ill IV - 1. Amount of selected elements released by hydrogen peroxide treatment of the fine earth fraction of the study sites . 125 2. Composition of the amorphous materials in the clay fraction and ratio of amorphous material in the fine earth fraction to content of silt and clay 126 3. Analysis of Bridge River tephra 129 viii Table Page IV - 4. Parts per million of Si, Fe and Al extracted by various reagents used in the isolation of clay fractions of selected soil samples and soil materials 130 5. Percentage of clay (<2/u) and fine clay (<0.02yu) separated by alkali and acid dispersion 131 6. Clay fraction components estimated from x-ray diffractograms 133 ix LIST OF FIGURES Figure Page I-l. Quaternary volcanic vents in Canada and adjacent areas of the United States 13 2. Sites of ash observations presented in table 3 and minimum fallout areas of the major ashfalls identified to date in western Canada 15 3. The location of sites where volcanic ash was found to be present in soils .... 32 II - 1. Location of study sites and adjacent climate stations 62 IV - 1. Flow sheet for separation of allophane and imogolite 122 2. I.R. spectra of amorphous Si and Al and of the clay fraction of ground Bridge River pumice, the site 1 Ah and II Bfb extracted after H202treatment A, alkali D and acid E dispersion 135 3. A, Imogolite-like material isolated from the Ah horizon at site 1; B, Single filament of imogolite-like material isolated from the IIBmb horizon at site 2 and characteristic of most imogolite like particles found in other horizons 137 X Figure Page IV - 4. Halloysite like particles observed in the electronmicrograph of the acid dispersed fine clay fraction of the site 2 IIBmb horizon 139 5. A, Gel like material associated with acid dispersed halloysite; B, Gel like material associated with acid dispersed IIBhfb material from site 1 140 ACKNOWLEDGEMENTS The author wishes to express his sincere appreciation to Dr. L.M. Lavkulich of the Department of Soil Science for his assistance and encouragement throughout the project. Sincere appreciation is also extended to Mr. L. Farstad, Head of the British Columbia Soil Survey Section, Canada Agriculture for his interest in the project and for making available the facilities at his disposal. Thanks are due to Dr. W.H. Mathews for reviewing the thesis and for his useful comments, to Dr. R.E. Carlyle for editing the thesis, to Dr. V.J. Krajina for the identification of some of the plant species encountered, to members of Canada Agriculture, Vancouver Soil Survey Section, the British Columbia Department of Agriculture Soil Survey Division, Dr. N. Keser, Mr. K. Klinka, Mr. R. Annas, Mr. E. Packee and Mr. M. Walmsley for providing soil samples and again to Mr. Walmsley for his help with the computer program. To his wife Valerie the author extends his gratitude and appreciation for her understanding and cheerful encourage• ment during the course of this study. INTRODUCTION The need for studies to identify the sources, distribu• tion and content of ash in soils in western Canada and to determine its influence on soil properties has been recognized for some time by pedologists.