A chronology of deglaciation and accompanying marine transgression in Maine

Conference · Mon Mar 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5878975

Dorion, C C ^[1]

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1. Univ. of Maine, Orono, ME (United States). Dept. of Geological Sciences

The rate of recession of the Laurentide Ice Sheet across Maine during Late Wisconsinan time is actively debated. Ice receding from the Gulf of Maine reached the position of the present coast and deposited Pond Ridge Moraine in approximately 90 meters of water. The time of aggradation is bracketed by molluscs preserved in marine clay that is interbedded with subaqueous outwash at 13,810 [plus minus] 90 (Nucula tenuis expansa). Molluscs in marine clay draping over the moraine at 13,370 [plus minus] 90 (Portlandia arctica) indicate ice withdrawal by this time. By 13,290 [plus minus] 85 the ice margin was at or beyond the marine limit near Gould Pond, Maine. These A.M.S. carbon 14 dates on marine macrofossils along this 130 kilometer transect from eastern coastal Maine to the inland marine limit yield an overall retreat rate of 212 flow-line meters per year. The marine transgression ended as land level rise exceeded sea level rise. The shoreline regressed to the present coast by 12,425 [plus minus] 110 as dated by Mytilus edulis deposited under washover fans on top of Pond Ridge Moraine. Core and X-ray logging, loss-on-ignition, and mollusc facies from six lake cores identify the basic stratigraphic framework along the 130 kilometer transect. Lithofacies are divided into two broad groups: intramorainal and intermorainal. Intramorainal lithofacies are further divided into vertical sequences of the distal and proximal moraine and also the complete cross section. Most of the 40 kilometer wide coastal morain belt is marked by intermorainal, ice distal, fossiliferous, thick deposits of laminated silty clays. Four facies describe the intermorainal stratigraphy: compact diamicton, a sparsely fossiliferous dropstone rich mud, highly fossiliferous laminated silty clays, and a cap of open-work, crudely-bedded pebble gravel.

• OSTI ID: 5878975
• Report Number(s): CONF-9303211-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GEOLOGIC DEPOSITS
DEPOSITION
STRATIGRAPHY
MAINE
MORAINES
ATLANTIC OCEAN
CONTINENTAL SHELF
GEOLOGIC HISTORY
GLACIERS
MOLLUSCS
PALEONTOLOGY
PLEISTOCENE EPOCH
ANIMALS
AQUATIC ORGANISMS
CENOZOIC ERA
CONTINENTAL MARGIN
DEVELOPED COUNTRIES
GEOLOGIC AGES
GEOLOGY
INVERTEBRATES
NORTH AMERICA
QUATERNARY PERIOD
SEAS
SURFACE WATERS
USA
580000* - Geosciences