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GEOREF RECORD

Brown and Gray Sands on the Virginia Shelf; color as a Function of Grain Size

Donald J. P. Swift and W. Richard Boehmer
Brown and Gray Sands on the Virginia Shelf; color as a Function of Grain Size
Geological Society of America Bulletin (1972) 83 (3): 877-883

Abstract

Brown iron-staining on coarse shelf sands has been taken as evidence of subaerial weathering, either in the source area or at the depositional site. However, we note that iron-staining can occur subaqueously, as well. We have found a close correlation between grain size and color on the inner Virginia shelf, with finer sands being olive-gray, and coarser sands being brown. We suggest that the sand-grain surfaces are in chemical equilibrium with their environment. The coarser sands are permeable, and are kept oxygenated by wave surge. The finer sands are relatively inpermeable, and are reduced by interstitial organic matter. While in any given case, brown iron-staining may have occurred sub-aerially, it may also have occurred in the modern marine environment. Hence brown iron-staining is not a definitive criteria for a relict origin or subaerial exposure of shelf sand.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 83
Serial Issue: 3
Title: Brown and Gray Sands on the Virginia Shelf; color as a Function of Grain Size
Pages: 877-883
Published: 1972
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
Accession Number: 1972-015435
Categories: Sedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. (incl. sketch map)
N36°34'60" - N39°28'00", W83°34'60" - W75°15'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute.
Update Code: 1972
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