THE GEOLOGY OF THE HARDWICK AREA, VERMONT
By RONALD H. KONIG and JOI-IN G. DENNIS
VERMONT GEOLOGICAL SUR\TEY CHARLES G. DOLL, State Geologist
Published by VERMONT DEVELOPMENT DEPARTMENT MONTPELIER, \TERMONT
BULLETIN No. 24 1964 TABLE OF CONTENTS Page ABSTRACT 7 INTRODUCTION ...... 7 Location ...... 7 Geologic Setting ...... S Previous Work ...... S Method ...... S Acknowledgments ...... 8 Physiography ...... 10 STRATIGRAPHY ...... 11 Introduction ...... 11 Stowe Formation ...... ... ...... ii General Statement ...... 11 Distribution ...... 11 Lithologic Detail ...... 13 Age...... 14 Missisquoi Formation ...... 14 General Statement ...... 14 Distribution ...... 14 Umbrella Hill Member ...... 15 Moretown Member. ...... 16 Age...... 17 Shaw Mountain Formation ...... 18 General Statement ...... IS Distribution ...... 18 Lithologic Detail ...... IS Age...... 19 Northfield Formation ...... 20 General Statement ...... 20 Distribution ...... 20 Lithologic Detail ...... 20 Age...... 21 Waits River Formation ...... 22 General Statement ...... 22 Distribution ...... 22 Age...... 23 Lithologic Detail ...... 23 Ayers Cliff Member ...... 25 PAGE Barton River Member 26 INTRUSIVE IGNEOUS Rocics ...... 27 Introduction ...... 27 Granodiorite Stocks ...... 28 Orhicular Granodiorite ...... 28 Granite Sills and Dikes ...... 33 Basic Dikes ...... 34 STRUCTURAL GEOLOGY ...... 35 Introduction and Structural Setting ...... 35 Major Structural Features ...... 35 Terminology ...... 35 Lowell Mountain Anticline ...... 36 Craftshury Homocline ...... 16 Brownington Syncline ...... 36 Willoughby Arch ...... 36 Minor Structural Features ...... 38 Terminology ...... 38 Foliation ...... 39 (a) Pre-Silurian Rocks ...... 39 (b) Silurian and Later Rocks ...... 40 (c) Age Relations of the Secondary Foliations ...... 43 Jointing ...... 47 Lineation ...... 48 Movement Pattern ...... 49 Theoretical Premises ...... 49 Movement ...... 49 METAMORPHISM