Study Site: Shatsky Rise A large igneous province in the Equatorial Pacific Index Tex86 = (III+IV + VI)/(II + III + IV + VI) proportional to temperature Biogeochemical Profiles of Climatic and Environmental Changes Inducing Deposition of Organic-rich Sediments during the Early Aptian Simon C. Brassell, Biogeochemical Laboratories, Department of Geological Sciences, Indiana University, Bloomington, IN 47405-1403 Biogeochemical data reflect environ-mental conditions providing evidence of (i) anoxia - from biomarkers, (ii) N2 fixation - from N isotopes, (iii) the abundance of cyanobacteria - from 2-Mehopanes, and (iv) sea surface temperatures - from TEX86. The evidence that cyanobacteria increase during cooler episodes suggests that either their populations are affected by environmental conditions, or that their biochemical production of 2-Mehopanes is environmentally controlled Early Aptian sediment core warm cooler warm cooler warm Shatsky Rise: West Central Pacific