Late miocene stable isotope stratigraphy of SE Atlantic ODP Site 1085:: Relation to Messinian events

High-resolution benthic oxygen isotope and XRF (Fe and Ca) records from Site 1085 drilled in the Kid-Cape basin (ODP Leg 175) are used to investigate global climate changes during the Late Miocene in relation to Messinian geological events. The cyclic fluctuations of the time series at Site 1085 enable us to establish a reliable chronology for the time interval 7.3-4.7 Ma. Spectral analysis of the delta(18)O record indicates that the 41-kyr period of orbital obliquity dominates the Late Miocene record. A global climate record was extracted from the oxygen isotopic composition of benthic foraminifera. Both long- and short-term variabilities in the climate record are discussed in terms of sea-level and deep-water temperature changes. The time interval 7.3-6.25 Ma characterized by low-amplitude delta(18)O variations is followed by a period marked by maximum in the 8110 values (6.25-5.57 Ma). At about 5.56 Ma, a rapid decrease in delta(18)O values is documented that may reflect a warming of deep-water temperature associated with a global warn-ling period. Comparison between the timing of the oceanic isotope events and the chronology of the Mediterranean Salinity Crisis suggest that global eustatic processes were not essential in the Mediterranean Salinity Crisis history. From our data, we infer that the global warmth documented in the Early/mid-Pliocene probably started during the Late Miocene (at 5.55 Ma). At the same time, the onset of evaporite deposition in the central basin of the Mediterranean Sea took place. Sharp changes in the sedimentation rates, mainly driven by terrigenous input at this site, are observed during the Messinian Stage. (C) 2002 Elsevier Science B.V. All rights reserved.