Miocene basement exhumation in the Central Alps recorded
by detrital garnet geochemistry in foreland basin deposits

Stütenbecker, Laura; Tollan, Peter; Madella, Andrea; Lanari, Pierre

doi:10.5194/se-2019-98

Cited by 2 publications

(19 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The thickest section of the preserved UFM (∼ 1500 m) is situated to the west of Lucerne (Matter, 1964). The geochemistry of detrital garnet in the UFM records the first signal of erosion of the external massifs by ∼ 14 Ma at the latest (Stutenbecker et al, 2019).…”

Section: Upper Freshwater Molassementioning

confidence: 99%

“…1), contain voluminous Variscan U-Pb plutonic rocks (Schaltegger, 1994). While the external massifs of the northern part of Central Alps also contain abundant Variscan crustal material (von Raumer et al, 2003;Engi et al, 2004;Franke, 2006), they were not exposed to erosion until ∼ 14 Ma (Stutenbecker et al, 2019).…”

Section: Variscan Orogenymentioning

confidence: 99%

“…Separate zircon grains were mounted on double-sided tape (tape mount) on a 1 acrylic or epoxy disc without polishing. For all samples 120-140 grains were randomly selected for LA-ICP-MS analysis to avoid biases and to capture all major age components (> 5%) (Vermeesch, 2004). All grains were depth-profiled using a Photon Machines Analyte G2 ATLex 300si ArF 193 nm excimer laser combined with a Thermo Scientific™ Element 2™ single-collector, magneticsector ICP-MS, following analytical protocols of Marsh and Stockli (2015).…”

Section: Zircon U-pb Laser Ablation-inductively Coupled Plasma-mass Smentioning

confidence: 99%

“…Furthermore, trace elements and REEs can be used to fingerprint zircon with mantle affinity (i.e., kimberlites and carbonatites; Hoskin and Ireland, 2000), hydrothermal zircon (Hoskin, 2005), or zircon that grew or recrystallized under high-grade metamorphic conditions (Rubatto, 2002). Furthermore, Ce and Eu anomalies in zircons have been used as proxies for magmatic oxidation states (Trail et al, 2012;Zhong et al, 2019) and Ti in zircon as a crystallization thermometer (Watson et al, 2006). Detrital studies have utilized these techniques to identify characteristic zircon signatures from non-typical sources (e.g., Anfinson et al, 2016;Barber et al, 2019).…”

Section: Zircon Elemental Analysismentioning

confidence: 99%

“…Yet, such insights are of critical importance for reconstructing the causal relationships between orogenic events and the basinal stratigraphic response. In the recent years, advances in isotopic provenance tracing techniques, including detrital mica 40 Ar/ 39 Ar dating (e.g., von Eynatten et al, 1999;von Eynatten and Wijbrans, 2003), zircon fission track dating of detrital clasts (Spiegel et al, 2000), detrital garnet and epidote geochemical analysis (Spiegel et al, 2002;Stutenbecker et al, 2019), and detrital zircon U-Pb geochronology (e.g., Malusà et al, 2016;Anfinson et al, 2016;Lu et al, 2018;Sharman et al, 2018a) have offered more quantitative links to Alpine geodynamic processes, revealed through seismic tomography imaging (Lippitsch et al, 2003;Fry et al, 2010;Hetényi et al, 2018) or bedrock geochronology (synthesized by Boston et al, 2017). In this study, we integrate high-density U-Pb and trace and rare-earth element analysis of detrital zircon from the late-Eocene to mid-Miocene stratigraphic record of the Swiss Molasse Basin to elucidate the tectonic activity and unroofing history of the Central Alps.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Tectonic exhumation of the Central Alps recorded by detrital zircon in the Molasse Basin, Switzerland

et al. 2020

View full text Add to dashboard Cite

Abstract. Eocene to Miocene sedimentary strata of the Northern Alpine Molasse Basin in Switzerland are well studied, yet they lack robust geochronologic and geochemical analysis of detrital zircon for provenance tracing purposes. Here, we present detrital zircon U–Pb ages coupled with rare-earth and trace element geochemistry to provide insights into the sedimentary provenance and to elucidate the tectonic activity of the central Alpine Orogen from the late Eocene to mid Miocene. Between 35 and 22.5 ± 1 Ma, the detrital zircon U–Pb age signatures are dominated by age groups of 300–370, 380–490, and 500–710 Ma, with minor Proterozoic age contributions. In contrast, from 21 Ma to ∼ 13.5 Ma (youngest preserved sediments), the detrital zircon U–Pb age signatures were dominated by a 252–300 Ma age group, with a secondary abundance of the 380–490 Ma age group and only minor contributions of the 500–710 Ma age group. The Eo-Oligocene provenance signatures are consistent with interpretations that initial basin deposition primarily recorded unroofing of the Austroalpine orogenic lid and lesser contributions from underlying Penninic units (including the Lepontine dome), containing reworked detritus from Variscan, Caledonian–Sardic, Cadomian, and Pan-African orogenic cycles. In contrast, the dominant 252–300 Ma age group from early Miocene foreland deposits is indicative of the exhumation of Variscan-aged crystalline rocks from the Lepontine dome basement units. Noticeable is the lack of Alpine-aged detrital zircon in all samples with the exception of one late Eocene sample, which reflects Alpine volcanism linked to incipient continent–continent collision. In addition, detrital zircon rare-earth and trace element data, coupled with zircon morphology and U∕Th ratios, point to primarily igneous and rare metamorphic sources. The observed switch from Austroalpine to Penninic detrital provenance in the Molasse Basin at ∼ 21 Ma appears to mark the onset of synorogenic extension of the Central Alps. Synorogenic extension accommodated by the Simplon fault zone promoted updoming and exhumation the Penninic crystalline core of the Alpine Orogen. The lack of Alpine detrital zircon U–Pb ages in all Oligo-Miocene strata corroborate the interpretations that between ∼ 25 and 15 Ma, the exposed bedrock in the Lepontine dome comprised greenschist-facies rocks only, where temperatures were too low for allowing zircon rims to grow, and that the Molasse Basin drainage network did not access the prominent Alpine-age Periadriatic intrusions located in the area surrounding the Periadriatic Line.

show abstract

Section: Upper Freshwater Molassementioning

confidence: 99%

Section: Variscan Orogenymentioning

confidence: 99%

Section: Zircon U-pb Laser Ablation-inductively Coupled Plasma-mass Smentioning

confidence: 99%

Section: Zircon Elemental Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tectonic exhumation of the Central Alps recorded by detrital zircon in the Molasse Basin, Switzerland

et al. 2020

View full text Add to dashboard Cite

show abstract

Two glaciers and one sedimentary sink: the competing role of the Aare and the Valais glaciers in filling an overdeepened trough inferred from provenance analysis

Schwenk

Stütenbecker²,

Schläfli

et al. 2022

E&G Quaternary Sci. J.

Self Cite

View full text Add to dashboard Cite

Abstract. The extent and distribution of glaciers on the Swiss Plateau during the Last Glacial Maximum (LGM) can be determined from the geological record. However, similar reconstructions for the glaciations that preceded the LGM are far more difficult to be made due to the destruction of suitable sedimentary records through recurring glaciations or due to the inaccessibility of preserved records. Here, we explored Quaternary sediments that were deposited during the Marine Isotope Stage (MIS) 8 glaciation at least around 250 ka, and which were recovered in a drilling that was sunk into an overdeepened bedrock trough west of Bern (Switzerland). We analyzed the sediment bulk chemical composition of the deposits to investigate the supply of the material to the area by either the Aare Glacier, the Saane Glacier, or the Valais Glacier, and we complement this investigation with the results of heavy mineral analyses and geochemical information from detrital garnet. The potential confluence of the Valais and the Aare glaciers in the Bern area makes this location ideal for such an analysis. We determined the sediment bulk chemical signal of the various lithological units in the central Swiss Alps where the glaciers originated, which we used as endmembers for our provenance analysis. We then combined the results of this fingerprinting with the existing information on the sedimentary succession and its deposition history. This sedimentary suite is composed of two sequences, Sequence A (lower) and Sequence B (upper), both of which comprise a basal till that is overlain by lacustrine sediments. The till at the base of Sequence A was formed by the Aare Glacier. The overlying lacustrine deposits of an ice-contact lake were mainly supplied by the Aare Glacier. The basal till in Sequence B was also formed by the Aare Glacier. For the lacustrine deposits in Sequence B, the heavy mineral and garnet geochemical data indicate that the sediment was supplied by the Aare and the Saane glaciers. We use these findings for a paleogeographic reconstruction. During the time when Sequence A and the basal till in Sequence B were deposited, the Aare Glacier dominated the area. This strongly contrasts with the situation during the LGM, when the Aare Glacier was deflected by the Valais Glacier towards the northeast. The Valais Glacier was probably less extensive during MIS 8, but it was potentially present in the area, and it could have been essential for damming a lake in which the material supplied by the Aare and the Saane glaciers accumulated. In conclusion, combining provenance with sedimentological data, we could document how sediment was supplied to the investigated overdeepened basin during the MIS 8 glacial period and how glaciers were arranged in a way that was markedly different from the LGM.

show abstract

Miocene basement exhumation in the Central Alps recorded by detrital garnet geochemistry in foreland basin deposits

Cited by 2 publications

References 15 publications

Tectonic exhumation of the Central Alps recorded by detrital zircon in the Molasse Basin, Switzerland

Tectonic exhumation of the Central Alps recorded by detrital zircon in the Molasse Basin, Switzerland

Two glaciers and one sedimentary sink: the competing role of the Aare and the Valais glaciers in filling an overdeepened trough inferred from provenance analysis

Contact Info

Product

Resources

About