18. MINERALOGICAL RECORD OF CYCLIC CLIMATE CHANGES IN MEDITERRANEAN MID-PLIOCENE DEPOSITS FROM HOLE 964A (IONIAN BASIN) AND FROM PUNTA PICCOLA (SICILY)¹

Frédéric Mélières,² Alain Foucault,² and Marie-Madeleine Blanc-Valleron²

ABSTRACT

Mid-Pliocene sediments from Ocean Drilling Program Hole 964A (Ionian Basin) and from Punta Piccola outcrop (Sicily, Italy) consist of light-colored carbonate-rich marls (decimeter to meter thick) alternating with dark-colored, carbonate-poor, organic matter–rich beds (1–25 cm thick). These sediments show cyclic variations in their mineralogical content, especially in the clay mineral relative percentages. Palygorskite and kaolinite are abundant in carbonated intervals, whereas smectite and chlorite dominate in dark ones. As palygorskite is known to originate from Africa, through wind transportation, we interpret these cyclic variations to be a result of the alternation of dry periods, with dominant eolian sedimentary input from the south, and humid periods, with dominant fluvial supply.

¹Robertson, A.H.F., Emeis, K.-C., Richter, C., and Camerlenghi, A. (Eds.), 1998. Proc. ODP, Sci. Results, 160: College Station, TX (Ocean Drilling Program).
² Laboratoire de Géologie, Muséum National d’Histoire Naturelle, 43 rue Buffon,75005 Paris, France. URA 1761 CNRS. foucault@cimrs1.mnhn.fr