Retreat of a tidewater margin of the Laurentide ice sheet in eastern coastal Maine, between ca. 14 000 and 13 000 C-14 yr BP

Ice-margin retreat, glacial processes, and associated marine environmental conditions were investigated along a tidewater margin of the Laurentide ice sheet in eastern coastal Maine. The ubiquitous presence of recessional mor aines that typically show crosscutting relationships indicates that numerou s stillstands and readvances interrupted net ice-margin retreat. Commonly, moraines exhibit changes in orientation associated with elevation changes, suggesting topographic control on retreat. Till, glaciofluvial facies, and glaciomarine sediment are the dominant components of the moraines. These se diments show that the ice terminated in the sea and that glacial meltwater played a key role in their deposition. The most continuous landforms in the study area are the Pond Ridge moraine and Pineo Ridge moraine system. Both landforms crosscut older moraines and contain ice-shove features, and cros scutting of moraines exists within the Pineo Ridge moraine system, indicati ng that the ice sheet readvanced during their formation. The Pond Ridge mor aine and Pineo Ridge moraine system are straighter across elevation changes , compared to other moraines in the area, implying that during their format ion, topography had Less of a destabilizing influence on ice-margin dynamic s. Foraminifera, Ostracoda, and mollusk species in ice-proximal and ice-dis tal glaciomarine sediments indicate that arctic to subarctic climatic condi tions existed during deglaciation, Despite the persistence of a cold enviro nment, 20 km of net ice-margin retreat occurred between ca. 14 000 and 13 0 00 C-14 yr B.P., mostly in contact with the sea.