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Seasonal Laurentide ice sheet melting during the "Mystery Interval" (17.5-14.5 ka)

Carlie Williams, Benjamin P. Flower and David W. Hastings
Seasonal Laurentide ice sheet melting during the "Mystery Interval" (17.5-14.5 ka)
Geology (Boulder) (August 2012) 40 (10): 955-958


The last deglaciation in the Northern Hemisphere was interrupted by two major stadials, the so-called "Mystery Interval" (17.5-14.5 ka) and the Younger Dryas (12.9-11.7 ka). During these events, the North Atlantic region was marked by cold surface conditions, yet simultaneous glacier and snowline retreat. Rerouting of Laurentide Ice Sheet meltwater from the Gulf of Mexico to an eastern or northern spillway may have reduced meridional overturning circulation at the onset of the Younger Dryas. However, this hypothesis has not been tested for the Mystery Interval. Paired Mg/Ca and delta (super 18) O measurements on foraminifera from laminated Orca Basin sediments in the Gulf of Mexico, constrained by 35 (super 14) C dates, document the timing of meltwater input with subcentennial resolution. Isolating the delta (super 18) O of seawater (termed delta (super 18) O (sub GOM) ) reveals three major melting episodes from ca. 17.5 ka until 12.9 ka, followed by a rapid cessation, consistent with meltwater rerouting at the onset of the Younger Dryas. Conversely, inferred meltwater flow to the Gulf of Mexico during the Mystery Interval does not support a simple routing event, but is consistent with glacier and snowline retreat. We suggest that summer melting of Northern Hemisphere ice sheets during this stadial may have been an important mechanism for enhanced winter sea-ice formation, hypercold winter conditions, and enhanced seasonality in the North Atlantic region.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 40
Serial Issue: 10
Title: Seasonal Laurentide ice sheet melting during the "Mystery Interval" (17.5-14.5 ka)
Affiliation: University of South Florida, College of Marine Science, St. Petersburg, FL, United States
Pages: 955-958
Published: 20120809
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 34
Accession Number: 2012-082362
Categories: Quaternary geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2012265; accessed on August 21, 2012
Illustration Description: illus.
Source Medium: WWW
N26°55'60" - N26°56'60", W91°20'60" - W91°19'60"
Secondary Affiliation: Eckerd College, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201243
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