Abstract

REY, Olga; LOPEZ, Liliana  and  LO MONACO, Salvador. Solar cycles identification during ocean anoxic event 3 (OEA3): la luna formation, venezuela . Rev. Fac. Ing. UCV [online]. 2009, vol.24, n.2, pp.5-12. ISSN 0798-4065.

The objective of this work was to study cyclicity reported on sub-millimeter scale in the La Luna Formation during Santonian time, and its relation with the end of the anoxic oceanic event 3 (AOE3), using electron microprobe analysis (EPMA), in the San Miguel river section, Mérida state. Five samples from this formation were analyzed and throughout perpendicular transects to lamination, qualitative information of chemical elements, COMPO images and bi-dimensional maps of the elements Si, Ca, O, C, Al, K, S, Zn, Fe and P were obtained. With the intention to analyze the cyclicity result of the variations in the distribution of Si and Ca, Fast Fourier Transform method was used. The duration of the identified cycles allows correlating them with Gleissberg, Hale, Schwabe and ENZO cycles. Changes in the position of intertropical convergence paleo-zone resulted in repeated alternation of high organic productivity periods and high rainfall and terrigenous input periods. These mechanisms were not responsible of the organic matter accumulation on this scale

Keywords : Santonian; Electron microprobe (EPMA); Cyclicity; Fast Fourier transform; Intertropical convergence paleo-zone.