Abstract:
The Paleocene and Eocene epochs represent an interval of both rapid and long-term global climate change. In this regard, early Paleogene carbon isotope records show a characteristic sequence of large amplitude changes between ca. 60 and 50 Ma (e.g., Zachos et al., 2001). These delta (super 13) C perturbations include an extreme high in the late Paleocene, a pronounced negative carbon isotope excursion (CIE) across the Paleocene/Eocene Thermal Maximum (PETM), and a prominent low at the early Eocene Climatic Optimum (EECO). The PETM is a particularly interesting event because the large ( approximately 3 per mil) and rapid (<10 k.y.) negative delta (super 13) C excursion likely reflects a massive input of carbon somewhat analogous to current anthropogenic inputs (Dickens, 1999). Although the responses of atmospheric and terrestrial systems to these fluctuations in the mass and dynamics of the global carbon cycle are critical to understanding the systemic consequences and potential feedbacks to such perturbations, they remain outstanding and largely open issues. In fact, there are remarkably few good Paleogene records of eolian or continental discharge across key time intervals of interest (e.g., Janecek and Rea, 1983; Hovan and Rea, 1992; Robert and Kennett, 1992; Schmitz et al., 2001; Crouch et al., 2003). Particularly, while studies of the flux of eolian material have depicted a less intense atmospheric circulatory system during periods of increased warmth, they have been limited to sites in the lower approximately 30 degrees of latitude, and so offer little insight into atmospheric circulation and intensity above 30 degrees of latitude (Janecek and Rea, 1983; Hovan and Rea, 1992). We present terrigenous component mass accumulation rate (MAR), elemental analysis (ICP-AES), grain-size, and mineralogy (XRD) data from Southern Hemisphere Ocean Drilling Program Sites 762 (Indian Ocean, Exmouth Plateau) and 752 (Indian Ocean, Broken Ridge) in order to characterize the terrigenous component composition and flux in response to periods of global climate change.