Two phase deglaciation incorporating a late-stage readvance in the Brunswick, Maine area

Conference · Mon Mar 01 04:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5722772

Borelli, C; Smity, P ^[1]

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1. Univ. of Southern Maine, Gorham, ME (United States). Dept. of Geoscience

Reinterpretation of late Wisconsinan glacial deposits indicate that retreat of the Laurentide ice margin occurred west of the marine limit in the Brunswick area. Marine transgression deposited the overlying Presumpscot Formation which locally contains organic rich, silty sand. A regionally extensive readvance deformed and truncated the uppermost glaciomarine sediments during the oceanic highstand. Striations and other ice flow indicators which are found underlying the Presumpscot Formation consistently trend NW-SE, while those found on exposed outcrops above the Presumpscot Formation dominantly trend NE-SW. These otherwise anomalous directional flow indicators support a late stage readvance of the ice sheet. Areally extensive, stratified, and locally imbricated outwash caps the glaciomarine sediments. Mineral composition of the basal outwash differs from the upper outwash sequences, supporting the readvance model by indicating different source areas. Multi-phase emergence characterized by terraced landforms caused a reworking and redeposition of sediment in a fluvial, tidally influenced environment. Localized eolian deposits record a late phase reworking of sediment.

• OSTI ID: 5722772
• Report Number(s): CONF-9303211--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 25:2
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
DEPOSITION
DEVELOPED COUNTRIES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
GEOLOGIC HISTORY
GEOLOGY
GLACIERS
MAINE
MORAINES
NORTH AMERICA
STRATIFICATION
STRATIGRAPHY
USA