New evidence on the history of the St. Francis Sunk Lands, northeastern Arkansas
A radiocarbon-dated pollen diagram from Big Lake, a complex of relict braided channels on the Little River and part of the St. Francis Sunk Lands in northeastern Arkansas, indicates that the basal lake sediments are less than 180 yr old. This date approximates the time of the New Madrid earthquake of 1811–1812. The formation of the St. Francis Sunk Lands has been attributed to mid-Holocene alluvial drowning, and effects of the New Madrid earthquake upon the Sunk Lands have recently been considered minimal. However, this new evidence suggests that Big Lake was either altered or formed in recent times, possibly by this seismic event.