Quartz and zircon decoupling in sandstone: Petrography and quartz cathodoluminescence of the Early Triassic continental Buntsandstein Group in Germany

Abstract

This study illustrates how decoupling of quartz and zircon can be used advantageously in provenance research. Thirty-eight fine-grained to coarsegrained arkose samples of the Early Triassic intracontinental Buntsandstein Group from the Central European Basin in Germany were analysed for their petrography and 1200 grains in 23 of these for their detrital quartz cathodoluminescence characteristics. The samples represent the Hessian and Thuringian sub-basins and the Eichsfeld-Altmark Swell separating them. The Hessian Sub-basin includes more metamorphic lithoclasts with a larger content of plutonic grains than are found further east in the Thuringian Subbasin. More than 90% of the detrital quartz from the eastern Thuringian Sub-basin produce medium to bright blue cathodoluminescence colours and corresponding spectra that are typical for igneous or high-temperature metamorphic origin. Differently, the quartz from the Hessian Sub-basin mostly luminesces brown and dark to medium blue, typical for a low-temperature metamorphic origin. Quartz from the Eichsfeld-Altmark Swell and the western Thuringian Sub-basin is a mixture between these origins. The quartz indicates different catchments for the sub-basins, possibly the Bohemian Massif and the Massif Central, with converging transport routes on and close to the eastern fringe of the swell. Taking published zircon data from the same samples into account, light mineral-zircon grain-size shifts are up to 2 Φ units. That can be explained by mineral decoupling due to different transport modes for quartz and zircon and different zircon-size availability in the source areas, exaggerated by combined aqueous-aeolian transport, as well as sample preparation-induced sorting. This study concludes that submerged highs significantly can influence continental sediment transport. Hence, vast, flat continental areas with submerged morphological highs and a seemingly straightforward transportation pattern may be more complex than expected. The results also illustrate that analysis of detritus that has been affected by different dominating transport modes, and further sorting during sampling and preparation can reveal additional source information.

Grain‐Size Control on Detrital Zircon Cycloprovenance in the Late Paleozoic Paradox and Eagle Basins, USA

“…However, there is no systematic offset between these bulk grain size values and sample median values. This is counter to theoretical and experimental findings from other studies that predict or observe ~0.20–0.46 mm offset between mean bulk sample and zircon grain size for the range of bulk grain sizes considered here, and zircon grains in these studies are uniformly smaller than bulk grain size (Augustsson et al, 2019; Garzanti et al, 2008; Resentini et al, 2013). Note that although median values are used in this study, the offset between mean and median grain dimension are <0.011 mm (long axis) and <0.007 mm (short axis) for all samples presented here.…”

Influencing Factors on Petrography Interpretations in Provenance Research—A Case-Study Review

“…Less than 40 samples (minor proportions in Götze [32], Mørk [33], von Eynatten and Gaupp [34], De Ros et al [35], Lippmann [36], Olivarius et al [37]) that are formally silt or conglomerates were included; they are mentioned in the text only when it is relevant for the discussion. The data include a sequence from the Permian to Palaeogene of Northern Europe (from Germany in the south to the Barents Sea in the north) with a transition from Permo-Triassic tectonically passive to rift-dominated continental and Jurassic to Cretaceous marine rift basins, to Palaeogene passive-margin marine environments [20,32,33,[36][37][38][39][40]. They also include coastal Cambrian passive-margin sandstone from Scandinavian Baltica [41][42][43], Silurian-Devonian intracratonic basin sandstone from the Paraná Basin in Brazil [35], Cretaceous Alpine deposits [34,44], rift-related Iberian Cretaceous to Pyrenean Palaeogene continental to marine deposits [45,46], and recent intracontinental sand from central Spain [47].…”

“…Lorentzen et al [42,43] and Ärlebrand [40] used the Gazzi-Dickinson method but applied a 30 µm and 20 µm matrix cut-off, respectively. von Eynatten and Gaupp [34] and Augustsson et al [20] used a modified Gazzi-Dickinson method with all rock fragments counted as such. Caja Rodríguez [45] is the only study specifying the use of the Indiana method.…”

“…Such nongeological (artificial) compositional (and analytical) biases have been particularly focused on for single-grain analysis in provenance research (e.g., [15][16][17]). Apparent differences in sediment compositions can also appear for the same samples based on the use of different point-counting methods or due to subjective interpretation of components for different operators (e.g., [18][19][20]). [1] (solid black lines), and the modified versions of Dickinson et al [2] (dashed black lines) and Weltje [3] (grey lines).…”

Drainage and environmental evolution across the Permo–Triassic boundary in the south‐east Germanic Basin (north‐east Bavaria)

“…2A). The Franconian Basin is east-bounded by the BM, the most significant exposure of Variscan basement rocks in Central Europe and considered the primary sediment source of the SE-CEBS (Schr€ oder et al, 1997;Dill & Klosa, 2011;Augustsson et al, 2018Augustsson et al, , 2019. Two tectonostratigraphic domains are recognized along the western BM: (i) the Moldanubian terrain (SE BM) (Fig.…”