Depositional History of an Oxbow Lake: Duck Cove of the Catawba River, Charlotte, NC

Document Type

Presentation

Presentation Date

3-2009

Abstract or Description

There are relatively few high-resolution terrestrial records of Holocene climate change for the southeastern United States. We are investigating the feasibility of obtaining such a record from oxbow lakes found along major drainages of the mid-Atlantic coast. The Catawba River is a single channel, meandering, incised river that drains 8556 square km from its headwaters on the Blue Ridge escarpment, through the Piedmont physiographic province of North and South Carolina to the Coastal Plain. The river currently is controlled by a series of dams and reservoirs operated by Duke Energy. Immediately downstream of the Cowans Ford Dam near Charlotte, NC, there is a free-flowing stretch where the Catawba River and its adjacent valley are characterized by steep valley walls, 3-4 fluvial strath terraces and a potential oxbow lake known as Duck Cove. The sediments of Duck Cove are meters thick and largely composed of laminated and bioturbated silty muds interbedded with centimeter thick fine sands with 14C-datable leaves and twigs dispersed throughout. Cores are capped by a planar-bedded fine to coarse sand up to 30 cm thick immediately overlying an organic rich layer dated at 1808 +/- 96 AD (calibrated radiocarbon age). The 30 cm thick sand is interpreted as a deposit from the 1916 flood that affected much of the region. Age dates from lower in the cores are inconclusive. Pollen analyses document abundant pine, oak and ragweed as well as corn, cotton, hemlock, fungal debris and charcoal suggesting that this alluvial environment was dominated by input from both a weedy, fire-prone nearby upland and Piedmont sources. We conclude that Duck Cove and other oxbow lakes are promising candidates to contain a long term (Holocene) climate record for the southeastern United States.

Additional Information

Southeastern Section

Sponsorship/Conference/Institution

Geological Society of America Annual Meeting

Location

St. Petersburg, FL

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