HR: 1340h
AN: U43A-0821    [Abstracts]
TI: Lithologic and Mineral Magnetic Evidence for Holocene Millennial-scale Lake-level Fluctuations in the Northeastern United States
AU: * Li, Y
U43A-0821 AF: Department of Earth and Environmental Sciences, Lehigh University, 31 Williams Drive, Bethlehem, PA 18015 United States
AU: Yu, Z
EM: ziy2@lehigh.edu
AF: Department of Earth and Environmental Sciences, Lehigh University, 31 Williams Drive, Bethlehem, PA 18015 United States
AU: Kodama, K P
EM: kpk0@lehigh.edu
AF: Department of Earth and Environmental Sciences, Lehigh University, 31 Williams Drive, Bethlehem, PA 18015 United States
AB: Millennial-scale climate variability has been increasingly recognized as one of the most prominent features in the Holocene. However, regional responses, especially in terms of moisture conditions, are poorly documented and understood. Here we present lithologic and magnetic evidence from White Lake in northern New Jersey (USA) to show that low lake levels occurred at ~1.3, 3.0, 4.4, and 6.1 ka (1 ka = 1000 cal yr BP). The low lake levels are indicated by heterogeneous coarse calcareous sediment layers showing strong magnetic intensities. These detrital layers were likely formed during low stands when shallow-water marls were exposed, oxidized, transported, and redeposited. This interpretation is supported by laboratory experiments showing that oxidation of marls can produce new magnetic minerals and thus lead to elevated magnetic intensities. The dry periods inferred from the low lake levels of White Lake appear to occur concurrently with the cold periods recorded in the North Atlantic sediments. The millennial-scale dry/wet cycles inferred from the lake-level fluctuations of White Lake closely correlate with the cold/warm cycles documented in the North Atlantic region, suggesting sensitive moisture responses to Holocene millennial-scale climate variability in the mid-latitude northeastern United States. The low lake level at ~4.4 ka in White Lake occurred almost concurrently with the ~4.2 ka drought events recorded in other parts of the world, lending support to the widespread nature of the ~4.2 ka drought in the Holocene.
DE: 1512 Environmental magnetism
DE: 1637 Regional climate change
DE: 1812 Drought
DE: 1845 Limnology (0458, 4239, 4942)
SC: Union [U]
MN: Fall Meeting 2005