The environmental significance of iron-stained quartz grains on the southeastern United States Atlantic shelf

Abstract

An examination of approximately 1,000 continental shelf, beach and river samples from the Atlantic southeastern United States shows that there are significant differences in the percentages of iron-stained quartz grains in two sand-size fractions in each of these major environments. More iron-stained quartz is found in sediments of rivers draining the Piedmont province than those draining the coastal plain. The presence of iron-stained quartz on the shelf may be due in large part to the contributions of rivers during the Pleistocene rather than subaerial weathering of shelf sediments, as indicated by shelf abundance anomalies related to river mouths. These same shelf anomalies are evidence of lack of extensive lateral transportation of sediment on the shelf. Abrasion is apparently not effective in removing the iron coating from the quartz grains in any environment, even in the beach environment.