EGU21-8980
https://doi.org/10.5194/egusphere-egu21-8980
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Alternatives to zircon in sedimentary provenance analysis: A case study in detrital garnet U-Pb and trace-element analysis

Chris Mark1, Laura Stutenbecker2, Sergio Andò3, Gary O'Sulivan1, and J. Stephen Daly1
Chris Mark et al.
  • 1University College Dublin, College of Science, School of Earth Sciences, Belfield, Dublin, Ireland (chris.mark@ucd.ie)
  • 2Institute of Applied Geosciences, Technische Universität Darmstadt, Darmstadt, Germany
  • 3Department of Earth and Environmental Sciences, Università di Milano-Bicocca, Milan, Italy

Provenance analysis of clastic sediment is a powerful tool to track the evolution of hinterland tectonics and sediment routing systems, for which detrital U-Pb geochronology has proved a popular and rapidly-growing technique. However, >90% of published studies employ zircon (3,691/3,933 results for the keywords detrital geochronology; Clarivate Analytics Web of Science), a mineral which exhibits strong fertility bias towards felsic to intermediate igneous sources, and is rare in metamorphic settings in the absence of anatexis (e.g., Moecher & Samson, 2006). Thus, the development of complementary proxies is desirable. Garnet group minerals are particularly promising because garnet is dominantly formed in metamorphic settings and is a rock-forming mineral in several common metamorphic lithologies; it is thus typically abundant in clastic sediment sourced from orogenic terranes. Moreover, it can incorporate sufficient U to be dated in-situ by the U-Pb method (e.g., Millonig et al., 2020).

Here we focus on the Oligo-Miocene pro-foreland basin of the European Alps. Evolving from a distal marine to a fluvial-alluvial environment affected by at least one major marine incursion, the basin preserves a rich record of tectonic and climatic change in the hinterland. We report detrital garnet U-Pb and trace-element data acquired by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), which we integrate with compositional data obtained by energy- and wavelength-dispersive X-ray spectroscopy (Stutenbecker et al., 2019), and crystallographic data from Raman spectroscopy. We integrate these results with detrital apatite, rutile, and zircon U-Pb data, and discuss the implications for Alpine tectonics and drainage evolution, and future potential for detrital garnet U-Pb analysis.    

Millonig, L., et al., 2020. Earth Planet. Sci. Lett. 552, 116589, doi: 10.1016/j.epsl.2020.116589

Moecher, D., & Samson, S., 2006, Earth Planet. Sci. Lett. 247, 252–266, doi: 10.1016/j.epsl.2006.04.035

Stutenbecker, L., et al., 2019, Solid Earth 10, 1581–1595, doi: 10.5194/se-10-1581-2019

How to cite: Mark, C., Stutenbecker, L., Andò, S., O'Sulivan, G., and Daly, J. S.: Alternatives to zircon in sedimentary provenance analysis: A case study in detrital garnet U-Pb and trace-element analysis, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8980, https://doi.org/10.5194/egusphere-egu21-8980, 2021.

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