Holocene Ocean-Climate Variations in the Gulf of California, Mexico

Abstract

Spectral analysis of a high-resolution sediment record from Alfonso Basin in the southern Gulf of California reveals decadal to millennial scale variations in sedimentation and biogenic production. Periods of variability occur at ca. 1480 yrs, 900 yrs, 350 yrs, 150 yrs and 100 yrs with a shift in the frequency of variability at about 3000 yrs B.P. Between 3000 and 7400 yrs B.P., climate in the Gulf was warmer and wetter with lower primary productivity. Sediments are terrigenous-and carbonate-rich with low amounts of organic carbon and biogenic silica. Periods of 150 and 350 years are related to productivity pulses. After 3000 yrs B.P., sediments are terrigenous-and organic-carbon rich with carbonate dissolution events with periodicities of 900+/-50 years superimposed on the 350 yr events.