Late Holocene changes in precipitation and hydrography recorded in marine sediments from the northeastern Caribbean Sea

We present a record of climate variability spanning the last 2000 years obt ained from sediment cores retrieved south and west of Puerto Rico in the no rtheastern Caribbean Sea, The records include lithological and mineral magn etic parameters as well as planktonic foraminifer data, For chronostratigra phic control, AMS C-14 and Pb-210/Cs-137 measurements were made, Harmonic a nalysis of the values of the mineral magnetic parameters "saturation isothe rmal remanent magnetization" (SIRM), "anhysteric remanent magnetization div ided by magnetic susceptibility" (ARM/chi), and "saturation isothermal rema nent magnetization divided by magnetic susceptibility" (SIRM/chi) indicate the existence of a similar to 200-year-long climate cycle in the northeaste rn Caribbean during the last 2000 years, The detected cycle may reflect cha nges in precipitation patterns over the low-latitude North Atlantic Ocean a nd surrounding continental areas. Higher organic carbon contents appear in the sediments both off southern and western Puerto Rico before and at the o nset of the Little Ice Age around A.D, 1300 to 1500, This is indicative of increased run off and/or enhanced surface productivity possibly associated with more intense wind-induced upwelling, Major changes in the geochemical and mineral magnetic records around A.D. 850-1000 concur with changes in ot her records from the Caribbean and North African regions indicating a shift toward a more humid climate over the low-latitude North Atlantic. (C) 2001 University of Washington.