Quartz-Monitor: Quartz as Monitor for Sediment Provenance from Source to Sink
Funded by the Austrian Academy of Sciences (2019-2022; FWF Project Nr. P-33038)
PI: Univ.-Prof. Dr. Roland Stalder co-PI: Michael Strasser
Sediment provenance analyses is a key tool for source-to-sink (S2S) research that aims at understanding and quantification of the coupling between sediment production in source terrains, routing and storage of sediments through fluvial systems, and accumulation in the sea across all time scales relevant for unraveling the history of our planet. Commonly employed techniques range from bulk-sediment methods to single-mineral methods, but challenges in quantifiying mixing ratios of metamorphic, igneous, and reworked sedimentary material, and the interplay of sedimentary processes and forcing functions in creating the studied stratigraphic record remain, mainly due to effects such as hyraulic sorting, weathering, and diagenesis and the relative low concentrations of commonly studied accessory minerals compared to the bulk sedimentary load in S2S systems.
This project aims at addressing this challenge by investigating intrinsic chemical variations of detrital quartz and its mineral and melt inclusions as an innovative new tool for sediment provenance analyses. Quartz belongs to the most abundant minerals in the Earth’s crust, is strongly resistant against mechanical and chemical weathering, and therefore is a major constituent of clastic sediments, but because of its very low chemical variability it has hitherto widely been ignored in sediment provenance analysis. In recent years, however, it has become evident that coupled substitutions of trace metals and protons (commonly referred to as hydrous (OH) defects) reflect petrogenetic factors, and individual quartz grains bear a wealth of information concerning their geological history. Furthermore, mineral and melt inclusions reflect the crystallisation history of quartz, too, but in contrast to OH-defects they are more inert towards thermal treatment. Knowing both characteristics enables the reconstruction of initial crystallisation condition and later metamorphic overprint.
We will use Fourier Transform Infrared Spectroscopy (FTIR), Electron Probe Micro Analyser (EPMA) and Secondary Ion Mass Spectroscopy (SIMS) to characterize detrital quartz as high-end analytical method constituting a novel approach and pushing the frontiers of sediment provenance research. This allows establishing the first comprehensive data set of detailed characterization of OH-defects and mineral- and melt inclusions in detrital quartz.. We will investigate well-constraint marine sedimentary systems that represent end-members of sedimentary margins (active vs. passive margins), and for which sediment provenance from different sediment source areas ranging from ancient orogens and rift shoulders (SW Africa, S America) to island arcs (Japan) and active orogens (Himalaya) is available. This approach allows for testing the hypothesis that OH defects and trace metals in monocrystalline quartz allow discrimination between grains from different source rock systems; and to constrain the applicability for quartz as monitor for provenance and analysis in large-scale S2S applications.
The project will be performed at the University of Innsbruck and lead by Prof. Roland Stalder (PI) and Prof. Michael Strasser (co-PI), in collaboration with international partners from the Laboratory of Sediment Provenance Studies at the University of Milano, the University of Sao Paolo and the Univ. of Heidelberg.