CONSTRAINING THE TIMING AND AMPLITUDE OF PROPOSED GLACIOEUSTASY DURING THE LATE PALEOZOIC ICE AGE WITH A CONTINUOUS CARBONATE RECORD IN SPAIN

Abstract

The Late Paleozoic Ice Age (345-260Ma) was a multi-phase glacial period that shares analogous characteristics with both the southern hemisphere glaciation of the Cenozoic as well as the glacial-interglacial cyclicity of the modern Plio-Pleistocene ice house. At the onset of ice house conditions (~330Ma), a globally synchronous exposure surface and depositional hiatus exposed paleotropical platforms around the world. Isotopically light meteoric waters dissolved and recrystallized the marine carbonates, resulting in a negative d13C excursion. The introduction of a light carbon sink in the form of these exposed carbonate platforms during glacial maxima predicts an alteration of the isotopic balance of the carbon cycle and thus the isotopic composition of oceanic DIC. Due to the formation of a foreland basin, local sea level in Northern Spain remained uniquely high during the global hiatus at ~330Ma. Unaltered d13C values of primary ocean DIC tied to high resolution biostratigraphy and U-Pb analyses allow us to use the isotopic response of the ocean as a new global proxy for sea level change to better constrain the timing and magnitude of glacioeustasy during the LPIA.