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Early chromite mining and agricultural clearance: Opportunities for the investigation of agricultural sediment dynamics in the Eastern Piedmont (USA)

American Journal of Science

By:
and
DOI: 10.2475/ajs.305.9.957

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Abstract

Many flood plains in the Eastern Piedmont (USA) are buried under deposits of sediment resulting from European agricultural clearance. Classic radioisotopic dating techniques cover temporal periods too short (137Cs, 210Pb) or too long (14C) to reliably date sediments deposited during periods of local European activity (1660-1900). Moreover, many potential biomarkers, such as pollen, degrade in oxic flood plain sediments. In the Baltimore, Maryland (USA) region, early chromite mining (1820 - 1880) occurred during periods of rapid agricultural clearance. Use of chromium (Cr) chemostratigraphic profiles in flood plain sediments tied to historical mining activity can provide improved precision in overbank accumulation rates and timing. Sediment cores were collected from the Red Run basin, which is part of the Baltimore Ecosystem Study, an urban Long-Term Ecological Research site. Trace metal chemostratigraphic profiles were measured and peaks in Cr concentration tied to historic mining activity. Dates from Cr chemostratigraphic profiles were combined with 137Cs dating to reconstruct flood plain sedimentation rates. Red Run early sedimentation rates (1820 - 1880) were higher (0.45 - 1.19 cm/yr) than more recent (1880 - 1963) rates (0.08 - 0.46 cm/yr). This indicates that Piedmont flood plain vertical sediment accumulation might have peaked before the peak in agricultural clearance, earlier than assumed by regional models. The Cr chemostratigraphy is applicable to a wider region including much of the Maryland and Pennsylvania (USA) Piedmont.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Early chromite mining and agricultural clearance: Opportunities for the investigation of agricultural sediment dynamics in the Eastern Piedmont (USA)
Series title:
American Journal of Science
DOI:
10.2475/ajs.305.9.957
Volume
305
Issue:
9
Year Published:
2005
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
American Journal of Science
First page:
957
Last page:
981
Number of Pages:
25