Solving igneous and tectonic problems using detrital sedimentary petrology

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Most continental margin sandstones and shales were derived from the adjacent continent, as sediment supplied by rivers. In ancient rocks, precisely determining how the sources of sandstones and shales have changed through time can be used to better understand volcanic activity and tectonics (faulting, uplift) in the source area. This grant proposal has two goals. First, to improve techniques for tracking sources of sediment to ancient rock successions, building on an extensive existing data base of mineralogical, geochronological and geochemical data from Cretaceous rocks of the Scotian Basin. The aim is by applying multiple techniques to achieve greater precision in identifying sources than is possible from one or two techniques. New procedures such as Mineral Liberation Analysis and hot-cathode cathodoluminescence will be applied, in a addition to "fingerprinting" and dating individual minerals. Second, to apply these techniques to four geological problems: (1) the tectonics of the Scotian Basin in the Early Cretaceous (100-140 Ma); (2) more generally, understanding uplift and tilting on the eastern Canadian margin and its role in supplying sediment to the adjacent basins; (3) identifying a possible Paleogene (~40 Ma) volcanic arc in southern Greece, important for understanding when subduction of the African plate beneath the Aegean microplate began; and (4) defining the stages of deformation and uplift in the main Hellenide mountain building phase in mainland Greece. In every case, better understanding the history of volcanism, faulting and uplift goes beyond local significance and has broader implications for geological processes elsewhere.