Geochemical history of Chesapeake Bay: Natural and anthropogenic influences

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:460502

Hill, J M; Park, J ^[1]; Brush, G ^[2]

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1. Maryland Geological Survey, Baltimore, MD (United States)
2. Johns Hopkins Univ., Baltimore, MD (United States)

Sediment cores, 4--5 m in length were collected at six sites in the mainstem Chesapeake Bay, as part of the NOAA National Status and Trends Program. The cores were described, X-rayed, optically scanned, and analyzed for textural parameters, Si and Al, trace metals, AVS, soluble iron, total carbon, nitrogen and sulfur. In addition, the cores were dated using Pb 210, C 14, and high temporal resolution pollen dating techniques. The cores indicate changes in the geochemical environment of the northern Chesapeake Bay, from an environment dominated by marine geochemical processes to one dominated by estuarine processes; this transition occurred approximately in the late 1930`s. Accompanying this transition is enrichment of the trace metals, as normalized to Al. Data from the cores also indicate periodic anoxic events have occurred in the main stem of the Chesapeake Bay since the time from European settlement, based on sulfur speciation and the behavior of Mn in the sediments. The behavior of the trace metals, in regard to changes through time, is strongly dependent on location in the Bay, reflecting different sources materials, and differences in geochemical environments of deposition. Changes in geochemistry of most of the cores, at approximately the same date, tentatively indicate events with Baywide influence are recorded in the sediments of these cores.

• OSTI ID: 460502
• Report Number(s): CONF-961149--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ALUMINIUM
CARBON 14
CHESAPEAKE BAY
GEOCHEMISTRY
HISTORICAL ASPECTS
IRON
ISOTOPE DATING
LEAD 210
METALS
MONITORING
NITRATES
SULFATES
WATER POLLUTION