Deglaciation of Penobscot Bay, Maine, USA

The Pond Ridge and Pineo Ridge moraines in downeast Maine likely formed at ~16.1 and ~15.7 ka respectively, during cold episodes recorded by δ18O dips in the GRIP ice core. The elapsed time between these ages is broadly consistent with retreat rates recorded by intervening De Geer moraines, which ar...

Full description

Bibliographic Details
Main Authors: Wrobleski, Emmy A., Hooke, Roger LeBaron
Format: Article in Journal/Newspaper
Language:English
Published: Atlantic Geoscience Society 2020
Subjects:
Online Access:https://journals.lib.unb.ca/index.php/ag/article/view/30478
id ftuninewbrunojs:oai:ojs.journals.lib.unb.ca:article/30478
record_format openpolar
spelling ftuninewbrunojs:oai:ojs.journals.lib.unb.ca:article/30478 2023-05-15T16:39:15+02:00 Deglaciation of Penobscot Bay, Maine, USA Wrobleski, Emmy A. Hooke, Roger LeBaron 2020-07-05 text/html application/pdf https://journals.lib.unb.ca/index.php/ag/article/view/30478 eng eng Atlantic Geoscience Society https://journals.lib.unb.ca/index.php/ag/article/view/30478/1882528081 https://journals.lib.unb.ca/index.php/ag/article/view/30478/1882526466 https://journals.lib.unb.ca/index.php/ag/article/view/30478 Copyright (c) 2020 Atlantic Geology Atlantic Geoscience; Vol. 56 (2020); 147 - 161 2564-2987 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion research-article 2020 ftuninewbrunojs 2022-07-11T11:42:13Z The Pond Ridge and Pineo Ridge moraines in downeast Maine likely formed at ~16.1 and ~15.7 ka respectively, during cold episodes recorded by δ18O dips in the GRIP ice core. The elapsed time between these ages is broadly consistent with retreat rates recorded by intervening De Geer moraines, which are readily visible on LiDAR imagery and are believed to be approximately annual. North-northwestward from the southwesterly extension of the Pond Ridge moraine there are three pairs of prominent moraines that are relatively continuous across the study area and could be reliably extrapolated across intervening water bodies. Retreat rates recorded by De Geer moraines suggest that these pairs formed at 15.7-15.8 ka, 15.5-15.6 ka, and ~15.5 ka. Although retreat appears to have occurred slightly faster across Penobscot Bay, a significant calving bay does not seem to have developed there. Instead, the ice margin remained relatively straight, retreating to the north-northwest. De Geer moraines become more widely spaced northward and vanish after ~15.5 ka when the ice margin was north of the head of Penobscot Bay and of Pineo Ridge. This likely reflects higher retreat rates during the initial phases of the Bølling warm period. Just south of Pineo Ridge there were two ice lobes; one retreated to the north and one to the northwest. The latter retreated more rapidly, while the former experienced numerous minor readvances and stillstands until finally pausing at the location of Pineo Ridge. A stillstand of this lobe then resulted in deposition of the Pineo Ridge moraine complex. Article in Journal/Newspaper ice core University of New Brunswick: Centre for Digital Scholarship Journals Pond Ridge ENVELOPE(-93.550,-93.550,-73.417,-73.417)
institution Open Polar
collection University of New Brunswick: Centre for Digital Scholarship Journals
op_collection_id ftuninewbrunojs
language English
description The Pond Ridge and Pineo Ridge moraines in downeast Maine likely formed at ~16.1 and ~15.7 ka respectively, during cold episodes recorded by δ18O dips in the GRIP ice core. The elapsed time between these ages is broadly consistent with retreat rates recorded by intervening De Geer moraines, which are readily visible on LiDAR imagery and are believed to be approximately annual. North-northwestward from the southwesterly extension of the Pond Ridge moraine there are three pairs of prominent moraines that are relatively continuous across the study area and could be reliably extrapolated across intervening water bodies. Retreat rates recorded by De Geer moraines suggest that these pairs formed at 15.7-15.8 ka, 15.5-15.6 ka, and ~15.5 ka. Although retreat appears to have occurred slightly faster across Penobscot Bay, a significant calving bay does not seem to have developed there. Instead, the ice margin remained relatively straight, retreating to the north-northwest. De Geer moraines become more widely spaced northward and vanish after ~15.5 ka when the ice margin was north of the head of Penobscot Bay and of Pineo Ridge. This likely reflects higher retreat rates during the initial phases of the Bølling warm period. Just south of Pineo Ridge there were two ice lobes; one retreated to the north and one to the northwest. The latter retreated more rapidly, while the former experienced numerous minor readvances and stillstands until finally pausing at the location of Pineo Ridge. A stillstand of this lobe then resulted in deposition of the Pineo Ridge moraine complex.
format Article in Journal/Newspaper
author Wrobleski, Emmy A.
Hooke, Roger LeBaron
spellingShingle Wrobleski, Emmy A.
Hooke, Roger LeBaron
Deglaciation of Penobscot Bay, Maine, USA
author_facet Wrobleski, Emmy A.
Hooke, Roger LeBaron
author_sort Wrobleski, Emmy A.
title Deglaciation of Penobscot Bay, Maine, USA
title_short Deglaciation of Penobscot Bay, Maine, USA
title_full Deglaciation of Penobscot Bay, Maine, USA
title_fullStr Deglaciation of Penobscot Bay, Maine, USA
title_full_unstemmed Deglaciation of Penobscot Bay, Maine, USA
title_sort deglaciation of penobscot bay, maine, usa
publisher Atlantic Geoscience Society
publishDate 2020
url https://journals.lib.unb.ca/index.php/ag/article/view/30478
long_lat ENVELOPE(-93.550,-93.550,-73.417,-73.417)
geographic Pond Ridge
geographic_facet Pond Ridge
genre ice core
genre_facet ice core
op_source Atlantic Geoscience; Vol. 56 (2020); 147 - 161
2564-2987
op_relation https://journals.lib.unb.ca/index.php/ag/article/view/30478/1882528081
https://journals.lib.unb.ca/index.php/ag/article/view/30478/1882526466
https://journals.lib.unb.ca/index.php/ag/article/view/30478
op_rights Copyright (c) 2020 Atlantic Geology
_version_ 1766029585922654208