Potential Discrimination of Belgian Black Marbles Using Petrography, Magnetic Susceptibility and Geochemistry

Abstract

Five varieties of Belgian black marbles are investigated in order to discriminate them. Their age ranges from Frasnian (Golzinne) to Visean (Dinant, Theux, Basècle, Lives). Three methods were used: petrography, magnetic susceptibility and geochemistry of major elements and Rare Earth Elements (REE). The petrographic analyze reveals 16 microfacies reflecting very quiet environments, sporadically perturbed by more energetic phenomena like turbidites or storms. These microfacies are integrated in two depositional models: a quiet offshore setting, below or close to the storm wave base (Salet, Basècles) and a shallow but very restricted zone, protected from waves and currents (Lives and Golzinne). The magnetic susceptibility results show that all the black marbles are characterized by very low, even slightly negative values, except the Golzinne one which shows higher values. Geochemical data allow to discriminate between the Theux black marble (low SiO 2 content), and the Basècles samples (low Al 2 O 3 , K 2 O and REE contents). These methods could be useful to determine/refine the origin of archaeological stones, even if all these analyses are destructive. Two archeologic samples were investigated in order to identify their possible origin.

Provenance analysis of Roman limestone artefacts from Colonia Iulia Emona (Marof archaeological site, Slovenia)

“…As the stratigraphic position of source areas in the Ig area is not uniform (Müllner, 1879; Šašel Kos, 1997), we expected that detailed provenance of the stone blocks from the Marof archaeological site could be ascertained by adopting a stratigraphic approach to provenance determination (Flügel, 2004). The microfacies method is used for the characterization of source areas (Boulvain et al, 2020; Brilli et al, 2010; Flügel, 2004; Galan et al, 1999; Hayward, 1995, 1996), but also for determining the provenance of artefacts (Boulvain et al, 2020; Brilli et al, 2011; Flügel, 1999; Flügel & Flügel, 1997; Šmuc et al, 2017). The accuracy of the microfacies method depends on the stratigraphic position of the source areas and the lithotypes used for artefact production.…”

Optimizing multiple non-invasive techniques (PXRF, pMS, IA) to characterize coarse-grained igneous rocks used as building stones

“…These technological advances were boosted by geological exploration and mining prospection (e.g., Fabre, 2020), environmental studies (e.g., Turner et al, 2018), and/or planetary rover missions (Edwards, 2018), along with many other applications. Specifically, in archaeometry, more and more non-destructive tools in spectroscopy and spectrometry are used to constrain the mineralogy, the chemical composition, and the physical properties of archeological material, by e.g., portable magnetic susceptibility (pMS; e.g., Williams-Thorpe and Potts, 2002;Szakmány et al, 2011), portable XRF (Oyedotun, 2018;Müskens et al, 2018;Sinnesael et al, 2018), portable Gamma-Ray spectrometry (pGRS; Puccini et al, 2014), handheld Laser-Induced Breakdown Spectroscopy (HH-LIBS; Senesi et al, 2018), portable Raman spectroscopy (e.g., Bersani and Madariaga, 2012) or spectrophotometry (Rogerio-Candelera, 2016;Boulvain et al, 2020). Combining these tools and the interpretation opens the door to high accuracy determination, discrimination, and sourcing of archeological materials (e.g., Liritzis and Zacharias, 2011;Papakosta et al, 2020).…”