Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Geochemical characteristics of glacial Lake Agassiz sediments and new ages for the Moorhead Phase at Fargo, North Dakota, USA

Xiuju Liu, Timothy G. Fisher, Kenneth Lepper and Thomas V. Lowell
Geochemical characteristics of glacial Lake Agassiz sediments and new ages for the Moorhead Phase at Fargo, North Dakota, USA
Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre (September 2014) 51 (9): 850-861

Abstract

The cause and age of the Moorhead low-water Phase of glacial Lake Agassiz remains uncertain. New geochemical (X-ray fluorescence (XRF) and elemental analysis) and chronological (optically stimulated luminescence (OSL)) data are used to test for evaporative enrichment within lacustrine sediment from Rabbit Lake, a small basin just above the highest Lake Agassiz strandline, and from two Lake Agassiz sediment cores at Fargo, North Dakota. Increases in quartz and gypsum interpreted to be of aeolian origin suggest increased aridity at Rabbit Lake sometime after 13 540-13 750 cal years BP. From the Fargo cores, lacustrine sediment of the Brenna and Sherack formations did not show convincing evidence for evaporative enrichment. However, this result is complicated by an erosional contact at the top of the Brenna Formation. A thin middle sand unit between the Brenna and Sherack formation clays is stratigraphically equivalent to the Poplar River Formation, West Fargo Member, but its properties differ from the fluvial sand of the West Fargo Member. Four OSL ages from the organic-poor, middle sand unit at Fargo range between 12.8+ or -0.2 and 13.5+ or -0.2 ka (with + or -1.6 ka uncertainty) and suggest lake level fell at Fargo at, or before, 13.1+ or -0.2 ka, the average of the OSL ages. With different sedimentological properties, and a difference of approximately 1750 years between the new OSL ages and previously published ages on the West Fargo Member sand, additional work is required to determine whether the middle sand unit is a new member of the Poplar River Formation, recording an earlier and different depositional environment than the West Fargo Member. From a plot of available ages for the Moorhead Phase, the regression remains poorly constrained in time.


ISSN: 0008-4077
EISSN: 1480-3313
Coden: CJESAP
Serial Title: Canadian Journal of Earth Sciences = Revue Canadienne des Sciences de la Terre
Serial Volume: 51
Serial Issue: 9
Title: Geochemical characteristics of glacial Lake Agassiz sediments and new ages for the Moorhead Phase at Fargo, North Dakota, USA
Affiliation: University of Toledo, Department of Environmental Sciences, Toldeo, OH, United States
Pages: 850-861
Published: 201409
Text Language: English
Summary Language: French
Publisher: National Research Council of Canada, Ottawa, ON, Canada
References: 44
Accession Number: 2014-085352
Categories: Quaternary geologyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. cols., 3 tables, sketch maps
N46°07'00" - N46°51'00", W96°54'00" - W96°12'00"
Secondary Affiliation: North Dakota State University, USA, United StatesUniversity of Cincinnati, USA, United States
Country of Publication: Canada
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from Canadian Science Publishing, NRC Research Press, Ottawa, ON, Canada. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201444
Close Modal

or Create an Account

Close Modal
Close Modal