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Table I Hydrostratigraphic unit at a dredged spoil placement site, Charles City County, VA. [Data are from 2002 annual monitoring report (Whittecar – Ref. 15); unit names from Mixon et al. (Ref. 7), McFarland (Ref. 8), and Johnson et al. (Ref. 9)]

From: Potential contaminants at a dredged spoil placement site, Charles City County, Virginia, as revealed by sequential extraction



Mining Fill

Mine spoils placed into old abandoned mine excavation. Commonly 4.6–7.6 m thick, beneath sediment disposal site. Mixed member: poorly sorted mixture of gravel, sand, silt, and clay;deposited by dumping; mostly under north half of refilled mine sites. Stratified member: stratified sands and mud deposited in a lake fromwest to east; mostly under the south end of refilled mine site.

Kennon Formation

Fining upward stream deposit (gravelly sand to silty clay) dominatedby thick clay-rich beds; 1.5–4.6 m thick; fills small recentvalleys carved into Tabb Formation beds.

Tabb Formation

Fining upward stream deposit (cobble beds to silty clay) dominatedby cobbles and gravelly sand; 3.7–6.7 m thick; carpets largevalley carved by the James River; forms broad terrace surface 4.6–6.1 m elevation.

Shirley Formation

Sand and gravel deposit (6.1 m thick) with silty clay cap (1.5 m thick); forms broad terrace at approximately 9.1–12.2 melevation, and terrace remnant beneath Shirley Plantation manorhouse

Nanj emoy-Marlborounit

Sandy silt-clay confining bed; glauconitic; compact; encounteredbeneath Tabb Formation and Mining Fill

Aquia-Potomac units

Layered gravelly aquifers and confining beds (42.7+ m thick)