Integrated high-precision analyses of Holocene relative sea-level changes: Lessons from the coast of Maine

Abstract

Research Article| September 01, 1996 Integrated high-precision analyses of Holocene relative sea-level changes: Lessons from the coast of Maine W. Roland Gehrels; W. Roland Gehrels 1Department of Geographical Sciences, University of Plymouth, Plymouth PL4 8AA, United Kingdom Search for other works by this author on: GSW Google Scholar Daniel F. Belknap; Daniel F. Belknap 2Department of Geological Sciences, University of Maine, Orono, Maine 04469 Search for other works by this author on: GSW Google Scholar Joseph T. Kelley Joseph T. Kelley 3Maine Geological Survey, State House Station #22, Augusta, Maine 04333 Search for other works by this author on: GSW Google Scholar Author and Article Information W. Roland Gehrels 1Department of Geographical Sciences, University of Plymouth, Plymouth PL4 8AA, United Kingdom Daniel F. Belknap 2Department of Geological Sciences, University of Maine, Orono, Maine 04469 Joseph T. Kelley 3Maine Geological Survey, State House Station #22, Augusta, Maine 04333 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1996) 108 (9): 1073–1088. https://doi.org/10.1130/0016-7606(1996)108<1073:IHPAOH>2.3.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation W. Roland Gehrels, Daniel F. Belknap, Joseph T. Kelley; Integrated high-precision analyses of Holocene relative sea-level changes: Lessons from the coast of Maine. GSA Bulletin 1996;; 108 (9): 1073–1088. doi: https://doi.org/10.1130/0016-7606(1996)108<1073:IHPAOH>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A suite of salt-marsh peat samples from four sites along the coast of Maine (Wells, Phippsburg, Gouldsboro, and Machiasport) has been analyzed using high-precision techniques to determine local relative sea-level trends and to evaluate proposed along-coast warping. A spatially variable set of relative sea-level records in Maine would have important implications for geophysical models that predict the response of the lithosphere during deglaciation and postglacial isostatic relaxation. These models are often at odds with observed relative sea-level indicators near the margins of former glaciation, including those from Maine.Assemblages of agglutinated benthic foraminifera occur in vertical zones on the surface of modern salt marshes in Maine and can be used to accurately locate former mean high water levels in cores. Additional tools in this study include accelerator mass spectrometer 14C dating of individual plant fragments and precise leveling of elevations. The amplification of M2 tidal range in the Gulf of Maine and the Bay of Fundy during the Holocene is modeled and applied to the mean high water data yielding best-estimate envelopes of mean tide level change for each location.Average long-term (thousands of years) mean tide level rise did not exceed ≈2 mm/yr at any time during the late Holocene at Wells, Phippsburg, and Machiasport. Between 4.5 and 3 ka (calibrated [cal]), the apparent rate of rise at Gouldsboro was higher than at any other site studied. This along-coast variation in the rate of mean tide level rise may reflect time of deglaciation, neotectonics, or differential isostatic adjustments. Between 8 and 5 ka (cal), only south-central Maine (Phippsburg) has a good record of relative sea-level change. At this locality, the rate of mean tide level rise was 5.0–8.8 mm/yr for the period 7.8−5.3 ka (cal), which may have resulted from collapse of a glacial forebulge. A slight acceleration of mean tide level rise has occurred during the past millennium in Gouldsboro and Machiasport. If 12 m downwarping in easternmost Maine occurred, as suggested in other publications, it must have happened prior to 5.7 ka (cal). This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.