An alkenone (U-37(K ')) quasi-annual sea surface temperature record (AD 1440 to 1940) using varved sediments from the Santa Barbara Basin

Analyses for C-37 alkenones (U-37(K')) and total organic carbon (TOC) in a varved core from the depocenter of the Santa Barbara Basin (34 degrees 13.5 'N, 120 degrees 01'W, 590 m water depth) have been made on an approximately 1-2 year basis from A.D. 1440 to 1940. The U-37(K')-based sea surface temp erature (SST) record oscillates around 15.5 degrees C with an amplitude of less than 3 degrees C at approximately interannual, decadal, and centennial frequencies. Historical El Nino/Southern Oscillation (ENSO) events are mat ched only partially by warmer U-37(K') SSTs. Three records: our SST, a publ ished Pacific coral delta(18)O, and a published tree-ring temperature anoma ly from the California valleys, show no evidence of colder temperatures dur ing the Little Ice Age (ca. 1500 to 1840 A.D.). Significantly, there is a s trong centennial-scale cyclicity In the U-37(K') SST record which approache s 1 degrees C in amplitude. TOC burial and alkenone fluxes are largely cont rolled by sedimentation rate as expressed in varve thickness. (C) 2000 Publ ished by Elsevier Science Ltd. All rights reserved.