This electronic thesis or dissertation has been downloaded from Explore Bristol Research, http://research-information.bristol.ac.uk Author: Welsted, J. E Title: Morphology and evolution of the Bay of Fundy, with emphasis on changes of sea level during the quaternary General rights The copyright of this thesis rests with the author, unless otherwise identified in the body of the thesis, and no quotation from it or information derived from it may be published without proper acknowledgement. It is permitted to use and duplicate this work only for personal and non- commercial research, study or criticism/review. You must obtain prior written consent from the author for any other use. It is not permitted to supply the whole or part of this thesis to any other person or to post the same on any website or other online location without the prior written consent of the author. 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MORPHOLOGYAND EVOLUTIONOF THE BAY OF FUNDY WITH EMPHASISON CHANGESOF SEA-LEVELDURING THE QUATERNARY VOLUMEI: TEXT by John Welsted Thesis submitted, to Bristol University for the degree of Doctor of Philosophy. Brandon, Manitoba March, 1971 11 MEMORANDUM The work contained in this dissertation has not been submitted to Bristol University or to any other degree awarding institution for considera- tion for the awarding of a degree or diploma. With the following exceptions the work is my own: (1) Shell samples were identified by Dr. Frances J. E. Wagner, Atlantic Oceanographic Laboratory, Dartmouth, Nova Scotia. (2) The programme for computing depth to bedrock using an Olivetti 101 calculator was devised by Dr. F. Hewitt, National Computing Centre, Manchester. (3) Pollen analysis was carried out by Dr. K. Crabtree, Department of Geography, Bristol University. Where reference is made to research carried out by other workers it is acknowledged in the text. J. Welsted. 111 ACKNOWLEDGEMENTS Research for this dissertation was made possible by grants from the following organizations: The New Brunswick Research and Productivity Council; Brandon University, Brandon, Manitoba; The National Research Council of Canada; and the Defence Research Board of Canada. Officers of the Maritime Marsh Rehabilitation Administration (M. M.R. A. ) in Truro, Nova Scotia made available unpublished large scale maps of some of the marsh areas, and also the records from borings made in connection with the construction of dams across some of the rivers which drain the marshes. Similarly Warnock Hersey International Limited provided the writer with records of borings made in connection with the Amherst Bypass. While doing field work the writer received able assistance from Mr. Michael Doiron (1965) who was at the time a Grade 12 student at Oromocto High School, New Brunswick; Mr. Leo Dare (1966) and Mr. Tom Carter (1967) who were at the time undergraduate students at Brandon University. Many undergraduates at Brandon University, too numerous to name individually, helped the writer with analysis of data collected in the field, with map analysis, and with air-photo interpretation. Thanks are extended to Mr. Hugh McPhaddenof Saskatoon and to Mr. Bruce Downie of Winnipeg who draughted the maps and diagrams and to Mrs. Disa Davidson of Brandon who typed the dissertation. Finally, I thank Mr. D. Ingle-Smith of the Department of Geography of Bristol University for advice and more especially for encouragement to complete the dissertation, and my wife without whose help I would neither have started the dissertation nor have finished it. iv ABSTRACT The Bay of Fundy is an arm of the Atlantic Ocean that almost separates Nova Scotia from New Brunswick, the two provinces being joined only by the low Chignecto Isthmus. The geometrical proportions of the Bay are such that it has the greatest known tidal range in the world. Rocks exposed along the Fundy coast range in age from Precambrian to Recent, but there is a gap between the end of the Triassic and the Pleistocene. Variations in rock type, structure, exposure, and geomorpholo- gical history (including changes of sea-level) have combined to produce a great variety of coastal types, one of the most distinctive features of the Bay being the extensive tidal marshes and mud-flats. A trough existed in the Fundy area by Triassic times but it was not below sea-level. Continental sediments were deposited in the trough with interruptions by volcanic activity. Later, major drainage channels were established along what are now the Bay of Fundy and the Annapolis - Cornwallis Lowland. Early workers in the area claimed that they could recognize in New Brunswick and Nova Scotia the remnants of a peneplain that was formed by the end of the Cretaceous. Although the idea persisted for many years and is still referred to occasionally, it is shown that there is no basis for believing that such a landform developed. During the Pleistocene, New Brunswick Nova Scotia . and were covered by an ice sheet which at its maximumreached the Scotian Shelf. During deglaciation the ice sheet split along the Bay of Fundy and its Offshoots. V Glaciation and deglaciation resulted in changes of relative sea-level in the Bay. At times sea-level was higher than at present and at other times lower. Determination of exact changes of sea-level is complicated by the fact that tidal range in the past was not the same as it is now. The evidence for emergence consists of shell-bearing clays and marine-formed morphological features now above sea-level. Emergence of at least 130 feet on the New Brunswick side is indicated by the existence of shells at that height and there is some evidence for 250 feet of emergence. On the Nova Scotia coast the highest figure is 137 feet which might suggest that there has been tilting up to the north-west. However, there are no dates for the 250-foot and 137-foot levels so they cannot be correlated. Submergence of the Fundy coast is indicated in places by its outline, by the depth of river channels, by information from the continental shelf, by the existence of buried organic materials, and possibly by some historical evidence. The amount of submergence indicated by the first two lines of evidence is difficult to measure, but a figure of at least 150 feet is suggested although exactly when sea-level was 150 feet lower than at present is not known. In the case of buried organic materials, dating is easier, a figure of -39 feet for 4040 years ago having been recorded. During the Recent Epoch there has been an interplay between isostatic forces, tending to produce; emergence, and eustatic sea-level changes, tending to produce submergence. Soon after deglaciation, about 12,500 BP, Chignecto Isthmus was flooded, but isostatic recovery resulted in emergence of the Isthmus by 10,600 BP. Over the past 6,000 years the tidal range in the Bay of Fundy has been increasing which may account for the submergence of vi many of the trees and peat layers along the coast. However, tidal range may have reached its maximum,in which case high-tide level will decrease giving the impression of emergence. The study here presented was commenced in 1965, and was aimed at a critical evaluation of existing knowledge and theory, with such additional work as time and circumstance might permit. New techniques rapidly became available as the work progressed, but with so large an area to cover it proved impossible to apply them as widely or thorough as the author would have liked. Many problems have thus had to be left' incompletely investigated, but it is hoped that suggestions made will be useful to future workers in the area. vii TABLE OF CONTENTS Page MEMORANDUM ........................... ii ACKNOWLEDGEMENTS ....................... iii ABSTRACT .......................... iv LIST OF TABLES ......................... ix LIST OF ILLUSTRATIONS ..... x VOLUME1: TEXT Chapter 1 INTRODUCTION ..................... Location and Delimitation of the Area Map, Chart, and Air-photo Coverage Accessibility Previous Work Purpose and Aims Time-Table and Method of Study 2 DESCRIPTION 13 .................... .. Physiographic Divisions of New Brunswick and Nova Scotia The Coast Submarine Topography and Sub-Bottom Deposits Tides 3 PRE-QUATERNARYDEVELOPMENT .............. 53 Conditions under which Triassic Rocks were Formed Structure Peneplains and Erosion Surfaces Evolution from Triassic to Quaternary 4 THE PLEISTOCENE: GLACIATIONAND DEGLACIATION 81 .... 5 QUATERNARYCHANGES OF SEA-LEVEL 94 ........... Complicating Factors Evidence of Emergence Deglaciation and Emergence Evidence of Submergence Summaryand Attempted Chronology of Quaternary Events 6 SUMMARYAND CONCLUSIONS 226 ............... REFERENCESCITED ........................ 232 viii VOLUMEII: ILLUSTRATIONSAND APPENDIXES Page FRONTISPIECE ILLUSTRATIONS ....................... 2 APPENDIX1: SHELL SAMPLEIDENTIFICATIONS 80 ......... APPENDIX2: LIST OF'RELEVANTRADIOCARBON DATES 83 ...... APPENDIX3: DEPTHFINDING USINGA HAMMERSEISMOGRAPH 91 ... APPENDIX4: POLLENANALYSIS DATA 95 ............. ix LIST OF TABLES Table Page 1 Some estimates for sea-level lowering during the Pleistocene 112 2 Minimum heights of post-glacial emergence at localities around the Bay of Fundy (heights in feet) 173 3 Maximumdepth of water in water bodies in the lower Saint John Valley 189 4 Location of submerged forests in New Brunswick and Nova Scotia 196 5 Depth of silt below Tantramar-Aulac-Amherst Marsh.