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Applications of U-Pb apatite and carbonate dating in Earth Sciences – Geokolloquium Dr. David Chew – Montag 18.11., 17:00

Applications of U-Pb apatite and carbonate dating in Earth Sciences

 Vortragender: Dr. David Chew (Trinity College, Dublin)

Precise and accurate U–Pb LA–ICPMS dating of U- and common Pb-bearing minerals (e.g. apatite, allanite, titanite, rutile and calcite) is becoming increasingly common due to advances in data reduction and increased availability of matrix-matched standards. This presentation considers U–Pb dating of apatite and calcite by LA-ICP-MS, focusing on both analytical challenges and geological applications. U-Pb dating of detrital apatite has a wide variety of applications in provenance studies, as apatite is almost always present in crystalline source rocks and its trace-element composition is inherently diverse. This enables the determination of general source-rock type for detrital apatite, which permits very specific provenance determinations when combined with detrital apatite U-Pb dating. Present approaches to U-Pb calcite dating suffer from large age uncertainties due to low U, high initial Pb, local open U-Pb system behaviour or the presence of different generations of carbonate. This presentation outlines the advantage of a U-Pb image mapping approach that spatially links age information with compositional, textural or structural features (SEM images or elemental maps). Applications include dating of diagenetic cements, syn-tectonic veins in orogenic belts, carbonate sedimentation and carbonate-hosted ore deposits.