Geology of the Taunton "Quadrangle, Bristol and Plymouth Counties Massachusetts By JOSEPH H. HARTSHORN GEOLOGY OF SELECTED QUADRANGLES IN MASSACHUSETTS v -GEOLOGICAL SURVEY BULLETIN 1163-D Prepared in cooperation with the Commonwealth of Massachusetts ' Department of Public ff^orks ,UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1967 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY William T. Pecora, Director For sale by the Superintendent of Documents, U. S. Government Printing Office Washington, D.C. 20402 CONTENTS ' Page Abstract__ ____-_____-_---___________----__---_----___-------_--- Dl Introduction._ ___-___----____________---_----_------_-------______ 1 Acknowledgments. __.._________,.______-_-_-___-___--______-___ 2 General setting.._.---_____________-_-___'__________-.__________ 2 Pre-Pleistocene geology and history._________________________________ 2 Stratigraphy._______________________----_--------_---_-.______ 3 Structure._______-----____________---------_-----_----____.___ 6 Geologic history._-_-_--__________----_-----_-----_--_-________ 7 Pleistocene geology____-_-_____-_______--__------___-__---_-_______ 8 Glacial erosion._______________________________________________ 8 Glacial deposits.__-_-_.-_______-___---------_---_-_------_.____ 9 Till..---------------------------------------------------- 9 Field and laboratory data..____________________________ 11 * Ground moraine.-.-----------^-------------------- 12 Flowtill. _-______-.-.---------.--------.....-...-_ 19 Textural data.____________________________________ 22 Origin of the till_____-----_-----_----------------.-_-__ 25 Drumlins.____-----___-___-_-__---_-__--_-___.--__________ 30 Water-laid deposits._______________________________________ 30 Glaciofluvial deposits._____-_----_-_-_-_-----__--______ 30 Ice-channel filling________________________________ 31 Kame or kame field__---_--------------------_---._ 33 '** Kame terrace.___-------------------------------._ 34 ^ Kame plain.______________________________________ 35 1 Outwash plain.________-_-_-__--_---__--______:___ 37 Undivided glaciofluvial deposits______ _______________ 38 Glaciolacustrine deposits.-----------------_--------_-.- 39 , Origin of the water-laid deposits..-------.------.-------- 43 Ice-contact slopes..------------------------------- 44 Ice-contact deposits_______---------___-__________ 46 Wind action __________________________________________________ 48 Eolian deposits..._____________________-______-__i_________ 48 Ventif acts ___._____1________________________________1_____ 51 Congeliturbate. _______________________________________________ 52 -i. Late-glacial history.___________________________________________ 56 General chronology_-___:___._-_-----. _____________________ 56 -> Local chronology __________________________________________ 57 Postglacial history.____________________________________________ 61 1 Economic features.________________________________________________ 63 ' References.. _ ______________________________________________________ 64 i UI » IV CONTENTS ILLUSTRATIONS Page PLATE 1. Geologic map of the Taunton quadrangle____ ______._ In pocket FIGURE 1. Index map of Massachusetts----.-.-------.---..__________ D3 2-6. Graphs showing cumulative curves for grain sizes in till: 2. North-central area.-__-__-.__----____..___---._____ 13 3. Pine Street area._________________________________ 15 4. Southwestern area___-_--_---------_-_------__--_- 16 5. Southeastern area_________________________________ 17 6. Orchard Street hill..._____________________________ 18 7. Graph showing cumulative curves for grain sizes in flowtills...- 20 8. Graph of range in grain size of till_----------_--_-_-___-_-- 23 9. Graphs showing number of till samples plotted against median grain size and against sorting coefficient.... __________ 24 10-13. Diagrams showing 10. Origin of flowtill __________________________________ 29 11. Cross sections of ice-channel fillings _________________ 32 12. Cross section of kame terrace.._____________________ 35 13. Profile of outwash plain____________________.___ 38 14. Photograph showing foreset bedding in kame delta._________ 41 15. Photograph showing topset bedding in kame delta..__.__-.__ 41 16. Photograph showing varved clay__._______________________ 42 17. Diagram showing origin of ice-contact slopes..__..__.___--__ 45 18. Graph showing cumulative curves for grain sizes in eolian material ______________________________________________ 50 19. Graph showing cumulative curves for grain sizes in con- geliturbate _ _-.__________________-----..---____.__--_ 53 20. Graph showing cumulative curves for grain sizes in material illustrating transition from till to eolian sand.--------- 55 TABLES Page TABLE 1. Statistical measures of till samples___-_____--_________--_ D12 2. Lithology of flowtill and associated gravels_________________ 27 3. Statistical measures of eolian material _____________________ 49 4. Statistical measures of congeliturbate._____________________ 53 5. Statistical measures of the transition from till to eolian sand__ 56 GEOLOGY OF SELECTED QUADRANGLES IN MASSACHUSETTS GEOLOGY OF THE TAUNTON QUADRANGLE, BRISTOL AND PLYMOUTH COUNTIES, MASSACHUSETTS By JOSEPH H. HARTSHORN ABSTRACT The preglacial history of the Taunton quadrangle of southeastern Massachu­ setts must be inferred from information on other parts of the Narrangansett basin of Rhode Island and Massachusetts because the quadrangle is almost entirely covered with glacial deposits. About 25 outcrops of bedrock, consisting of sandstone, shale, and conglomerate of the Rhode Island Formation of Penn- sylvanian age, occur in the area. Subsurface data indicate the existence of a large drift-filled preglacial valley below the Taunton River. Light-gray, yellowish-gray, and pale-yellowish-brown till is exposed over about 20 percent of the Taunton map area. Most of the till is of subglacial origin and was derived predominantly from sandstone of the Rhode Island Formation. Numerous glaciofluvial deposits in the area show evidence of having been laid clown in contact with ice. The general arrangement of the glaciofluvial or glaciolacustrine deposits suggests stagnation of blocks of ice in low areas and the formation of glaciofluvial deposits around and over the blocks. Flat-lying, lens-shaped bodies of flowtill overlie or are interbedded with sand and gravel deposits of ice-contact origin. Numerous kame plains, kame terraces, ice-channel fillings, kames and kame fields, and large bodies of stratified ice-contact deposits, not easily classifiable, indicate that isolated blocks of ice were present during their formation. Kame deltas and associated lake deposits, including varved clay, cover part of the quadrangle; some lake-bottom deposits are buried beneath younger outwash plains or swamps. A nearly continuous mantle of eolian sand covers most of the quadrangle to depths ranging from 2 to 5 feet. In places, ventifacts, composed chiefly of Dedham Granodiorite and volcanic rocks, and abraded on all sides, are common throughout the eolian sand. Intense frost action late in Pleistocene time is suggested by the wind-abraded ventifacts and by congeliturbate a mixture of clean, well-sorted eolian sand and silt and the underlying stratified or unstratified drift. INTRODUCTION The Taunton qua'drangle, in southeastern Massachusetts, contains a variety of glacial features whose interrelationship aids in establish - Dl D2 ing the probable mode by which the last continental ice sheet melted, and, at least in part, in reconstructing the late-glacial history. The general geology of the Taunton quadrangle was mapped dur­ ing a total of 135 working days in 1949, 1950, and 1951. The U.S. Geological Survey 7^-minute topographic sheet of the Taunton quad­ rangle was used as the base map. Aerial photographs were used to a limited extent. The composition and structure of the glacial deposits were observed in natural and artificial exposures. A 14-foot segmented hand auger was used where necessary in fine-grained materials, but it was useless in anything coarser than granule gravel. ACKNOWLEDGMENTS The study of the Taunton area was supervised by Prof. Kirk Bryan from its inception in 1949 until the death of Prof. Bryan in 1950. Some of the ideas stated in this paper should properly be credited to him. Frederick Johnson, of the R. S. Peabody Foundation for Archaeology, Andover, Mass., helped interpret the late-glacial chron­ ology, and the Foundation provided financial help in 1949. Most of the work on which this report is based was done as part of a cooperative program of the U.S. Geological Survey and the Mas­ sachusetts Department of Public Works. Mechanical analyses of sediments were made in the Department of Public Works soils laboratory. GENERAL SETTING The Taunton quadrange (fig. 1) is an area of about 55 square miles in Bristol and Plymouth Counties. It lies in the Seaboard Low­ land section of the New England physiographic province (Fenneman, 1938) and is a region of relatively low relief. The highest point in the area is the crest of Prospect Hill, slightly more than 200 feet above sea level. Most of the topographic features are formed by the large sand and gravel masses that mantle parts of the area. The bedrock topography markedly affects the present landscape only in the east­ ern part of the quadrangle, where three elongate hills with relief of about 70 feet, 100 feet, and 110 feet show a crude northwest-south­ east alinement. About 18 percent of the area is covered