Map of glacial limits and possible refugia in the southern Alexander Archipelago, Alaska, during the late Wisconsin glaciation
During the late Wisconsin glaciation (circa 26,000-13,000 carbon-14 yr BP) the Cordilleran glacier complex formed vast ice fields and large glaciers along the crest of the Coast Mountains. As these glaciers flowed west to the Pacific Ocean, they were joined by local glaciers originating on the highe...
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USGS Science Data Catalog
2003
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Online Access: | https://search.dataone.org/view/3e72dfba-ed21-495d-a9f1-eb4b83ca8888 |
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dataone:3e72dfba-ed21-495d-a9f1-eb4b83ca8888 2023-11-08T14:14:14+01:00 Map of glacial limits and possible refugia in the southern Alexander Archipelago, Alaska, during the late Wisconsin glaciation P.E. Carrara T.A. Ager J.F. Baichtal D. Paco VanSistine ENVELOPE(-136.27626,-131.12007,57.297565,54.215305) 2003-01-01T00:00:00Z https://search.dataone.org/view/3e72dfba-ed21-495d-a9f1-eb4b83ca8888 unknown USGS Science Data Catalog snow and ice cover bathymetry geologic history geospatial datasets maps and atlases Glacial limits Bathymetry Cordilleran ice sheet United States of America Alaska Southern Alexander Archipelago f02201 = Prince of Wales-OuterKetchikan f02130 = Ketchikan Gateway f02280 = Wrangell-Petersburg f02220 = Sitka Dataset 2003 dataone:urn:node:USGS_SDC 2023-11-08T13:39:11Z During the late Wisconsin glaciation (circa 26,000-13,000 carbon-14 yr BP) the Cordilleran glacier complex formed vast ice fields and large glaciers along the crest of the Coast Mountains. As these glaciers flowed west to the Pacific Ocean, they were joined by local glaciers originating on the higher reaches of the Alexander Archipelago (Mann and Hamiltion, 1995). This extensive volume of ice was channeled into deep troughs (present-day fiords) that formed major outlet glaciers, such as the glaciers that occupied Chatham Strait and Dixon Entrance. In several places along the coast, deep glacially scoured submarine troughs indicate that glaciers reached to the edge of the continental shelf. For instance, the glacier that extended into the Dixon Entrance trough is known to have extended to the edge of the continental shelf. Its retreat began sometime after 16,000-15,000 carbon-14 yr BP (Barrie and Conway, 1999). The exact extent of late Wisconsin cordilleran ice in southeastern Alaska is poorly known. Small-scale maps and reports of the region commonly show or imply ice extending west to the edge of the continental shelf (Capps, 1931; Coulter and others, 1965; Flint, 1971; Pewe, 1975; Denton and Hughes, 1981; and Prest, 1984). These maps relied heavily on earlier work, much of it of a reconnaissance nature. The map shows our interpretation of the limit of the Cordilleran ice sheet, which is more restricted than previous estimates, and possible refugium (an area that escaped the extensive glaciation of the late Wisconsin and so provided a suitable habitat for relict species) in the southern Alexander Archipelago during the late Wisconsin glaciation. In addition to the analysis of the bathymetric map, the limits of the Cordilleran ice sheet and possible refugia were also identified by analyses of aerial photographs, USGS topographic maps (1:63,360 and 1:250,000 scales), NOAA bathymetric charts (1:20,000 and 1:40,000 scales), previous literature, and reconnaissance fieldwork throughout the region. Ice-free areas that may have served as refugia include (1) high mountain nunataks (too small to show at map scale), (2) unglaciated ocean-facing slopes and forelands (Dahl, 1946), (3) the outer islands of the Alexander Archipelago (Worley, 1980), and (4) parts of the inner continental shelf exposed by the lowering of sea level during the late Wisconsin by an estimated 125 m (Bard and others, 1990). Dataset Archipelago glacier glaciers Ice Sheet Ketchikan Alaska USGS Science Data Catalog (via DataONE) Conway ENVELOPE(-61.422,-61.422,-62.841,-62.841) Coulter ENVELOPE(-58.033,-58.033,-83.283,-83.283) Dixon Entrance ENVELOPE(-132.003,-132.003,54.416,54.416) Flint ENVELOPE(-65.417,-65.417,-67.333,-67.333) Pacific ENVELOPE(-136.27626,-131.12007,57.297565,54.215305) |
institution |
Open Polar |
collection |
USGS Science Data Catalog (via DataONE) |
op_collection_id |
dataone:urn:node:USGS_SDC |
language |
unknown |
topic |
snow and ice cover bathymetry geologic history geospatial datasets maps and atlases Glacial limits Bathymetry Cordilleran ice sheet United States of America Alaska Southern Alexander Archipelago f02201 = Prince of Wales-OuterKetchikan f02130 = Ketchikan Gateway f02280 = Wrangell-Petersburg f02220 = Sitka |
spellingShingle |
snow and ice cover bathymetry geologic history geospatial datasets maps and atlases Glacial limits Bathymetry Cordilleran ice sheet United States of America Alaska Southern Alexander Archipelago f02201 = Prince of Wales-OuterKetchikan f02130 = Ketchikan Gateway f02280 = Wrangell-Petersburg f02220 = Sitka P.E. Carrara T.A. Ager J.F. Baichtal D. Paco VanSistine Map of glacial limits and possible refugia in the southern Alexander Archipelago, Alaska, during the late Wisconsin glaciation |
topic_facet |
snow and ice cover bathymetry geologic history geospatial datasets maps and atlases Glacial limits Bathymetry Cordilleran ice sheet United States of America Alaska Southern Alexander Archipelago f02201 = Prince of Wales-OuterKetchikan f02130 = Ketchikan Gateway f02280 = Wrangell-Petersburg f02220 = Sitka |
description |
During the late Wisconsin glaciation (circa 26,000-13,000 carbon-14 yr BP) the Cordilleran glacier complex formed vast ice fields and large glaciers along the crest of the Coast Mountains. As these glaciers flowed west to the Pacific Ocean, they were joined by local glaciers originating on the higher reaches of the Alexander Archipelago (Mann and Hamiltion, 1995). This extensive volume of ice was channeled into deep troughs (present-day fiords) that formed major outlet glaciers, such as the glaciers that occupied Chatham Strait and Dixon Entrance. In several places along the coast, deep glacially scoured submarine troughs indicate that glaciers reached to the edge of the continental shelf. For instance, the glacier that extended into the Dixon Entrance trough is known to have extended to the edge of the continental shelf. Its retreat began sometime after 16,000-15,000 carbon-14 yr BP (Barrie and Conway, 1999). The exact extent of late Wisconsin cordilleran ice in southeastern Alaska is poorly known. Small-scale maps and reports of the region commonly show or imply ice extending west to the edge of the continental shelf (Capps, 1931; Coulter and others, 1965; Flint, 1971; Pewe, 1975; Denton and Hughes, 1981; and Prest, 1984). These maps relied heavily on earlier work, much of it of a reconnaissance nature. The map shows our interpretation of the limit of the Cordilleran ice sheet, which is more restricted than previous estimates, and possible refugium (an area that escaped the extensive glaciation of the late Wisconsin and so provided a suitable habitat for relict species) in the southern Alexander Archipelago during the late Wisconsin glaciation. In addition to the analysis of the bathymetric map, the limits of the Cordilleran ice sheet and possible refugia were also identified by analyses of aerial photographs, USGS topographic maps (1:63,360 and 1:250,000 scales), NOAA bathymetric charts (1:20,000 and 1:40,000 scales), previous literature, and reconnaissance fieldwork throughout the region. Ice-free areas that may have served as refugia include (1) high mountain nunataks (too small to show at map scale), (2) unglaciated ocean-facing slopes and forelands (Dahl, 1946), (3) the outer islands of the Alexander Archipelago (Worley, 1980), and (4) parts of the inner continental shelf exposed by the lowering of sea level during the late Wisconsin by an estimated 125 m (Bard and others, 1990). |
format |
Dataset |
author |
P.E. Carrara T.A. Ager J.F. Baichtal D. Paco VanSistine |
author_facet |
P.E. Carrara T.A. Ager J.F. Baichtal D. Paco VanSistine |
author_sort |
P.E. Carrara |
title |
Map of glacial limits and possible refugia in the southern
Alexander Archipelago, Alaska, during the late Wisconsin glaciation |
title_short |
Map of glacial limits and possible refugia in the southern
Alexander Archipelago, Alaska, during the late Wisconsin glaciation |
title_full |
Map of glacial limits and possible refugia in the southern
Alexander Archipelago, Alaska, during the late Wisconsin glaciation |
title_fullStr |
Map of glacial limits and possible refugia in the southern
Alexander Archipelago, Alaska, during the late Wisconsin glaciation |
title_full_unstemmed |
Map of glacial limits and possible refugia in the southern
Alexander Archipelago, Alaska, during the late Wisconsin glaciation |
title_sort |
map of glacial limits and possible refugia in the southern
alexander archipelago, alaska, during the late wisconsin glaciation |
publisher |
USGS Science Data Catalog |
publishDate |
2003 |
url |
https://search.dataone.org/view/3e72dfba-ed21-495d-a9f1-eb4b83ca8888 |
op_coverage |
ENVELOPE(-136.27626,-131.12007,57.297565,54.215305) |
long_lat |
ENVELOPE(-61.422,-61.422,-62.841,-62.841) ENVELOPE(-58.033,-58.033,-83.283,-83.283) ENVELOPE(-132.003,-132.003,54.416,54.416) ENVELOPE(-65.417,-65.417,-67.333,-67.333) ENVELOPE(-136.27626,-131.12007,57.297565,54.215305) |
geographic |
Conway Coulter Dixon Entrance Flint Pacific |
geographic_facet |
Conway Coulter Dixon Entrance Flint Pacific |
genre |
Archipelago glacier glaciers Ice Sheet Ketchikan Alaska |
genre_facet |
Archipelago glacier glaciers Ice Sheet Ketchikan Alaska |
_version_ |
1782012147747782656 |