Ostracode-Shell Luminescence Dating for Quaternary Deposits

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ABSTRACTOSTRACODE-SHELL LUMINESCENCE DATING FOR QUATERNARY DEPOSITSThis proposal intends to build on preliminary feasibility tests, to develop a new luminescence clock for the direct dating of an important Quatemary paleoenvironmental proxy indicator: ostracode shells. Non-marine ostracode shells serve as proxy indicators of paleoenvironmental conditions in lakes, ponds, springs and streams. Presently these shells can be dated directly by radiocarbon methods, but a means to date them directly when older than 35-40 ka would provide opportunities for new discoveries in the worldwide effort to reconstruct details of paleoenvironmental histories from continental sedimentary records.Preliminary work by the PI indicates that ostracode shells have some desired luminescence properties. However, refined sample preparation protocols suitable for luminescence dating need to be developed, and almost nothing is known of their likely useful age range. Natural samples of ostracode shells will be collected from independently well-dated (by 14C) lacustrine beds (late Pleistocene age) from the lake Bonneville Basin (northwestern Utah) and from Mono Lake (eastem Califomia). The foundations for reliable luminescence dating protocols will be established. These protocols will then be applied to one or two samples older than ca. I00 ka, to extrapolate from the developmental tests. This research will form the basis of a graduate student's thesis project.