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

Solid Earth ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 1581-1595
Author(s):  
Laura Stutenbecker ◽  
Peter M. E. Tollan ◽  
Andrea Madella ◽  
Pierre Lanari
Keyword(s):  
Foreland Basin ◽  
Alluvial Fan ◽  
Sediment Supply ◽  
European Alps ◽  
Central Alps ◽  
Drainage Networks ◽  
Northern Alpine Foreland ◽  
Relief Distribution ◽  
Alpine Foreland ◽  
Alpine Foreland Basin

Abstract. The Neogene evolution of the European Alps was characterized by the exhumation of crystalline basement, the so-called external crystalline massifs. Their exhumation presumably controlled the evolution of relief, distribution of drainage networks, and generation of sediment in the Central Alps. However, due to the absence of suitable proxies, the timing of their surficial exposure and thus the initiation of sediment supply from these areas are poorly constrained. The northern Alpine foreland basin preserves the Oligocene to Miocene sedimentary record of tectonic and climatic adjustments in the hinterland. This contribution analyses the provenance of 25 to 14 Myr old alluvial fan deposits by means of detrital garnet chemistry. Unusually grossular- and spessartine-rich garnet is found (1) to be a unique proxy for identifying detritus from the external crystalline massifs and (2) to occur abundantly in ca. 14 Myr old deposits of the foreland basin. In contrast to previous assumptions, we therefore propose that the external massifs were already exposed to the surface ca. 14 Myr ago.

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

2019 ◽  
Author(s):  
Laura Stutenbecker ◽  
Peter M. E. Tollan ◽  
Andrea Madella ◽  
Pierre Lanari
Keyword(s):  
Foreland Basin ◽  
Crystalline Basement ◽  
Alluvial Fan ◽  
Sediment Supply ◽  
European Alps ◽  
Central Alps ◽  
Drainage Networks ◽  
Relief Distribution ◽  
Minimum Age ◽  
Alpine Foreland Basin

Abstract. The Neogene evolution of the European Alps was characterized by the exhumation of crystalline basement, the so-called external crystalline massifs. Their exhumation presumably controlled the evolution of relief, distribution of drainage networks and generation of sediment in the Central Alps. However, due to the absence of suitable proxies, the timing of their surficial exposure, and thus the initiation of sediment supply from these areas, are poorly constrained. The northern alpine foreland basin preserves the Oligocene to Miocene sedimentary record of tectonic and climatic adjustments in the hinterland. This contribution analyses the provenance of 25 to 14 My-old alluvial fan deposits by means of detrital garnet chemistry. Unusually grossular- and spessartine-rich garnets are found to be unique proxies for identifying detritus from the external crystalline massifs. In the foreland basin, these garnets are abundant in 14 My-old deposits, thus providing a minimum age for the surficial exposure of the crystalline basement.

scholarly journals Miocene high elevation in the Central Alps

Solid Earth ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 2615-2631
Author(s):  
Emilija Krsnik ◽  
Katharina Methner ◽  
Marion Campani ◽  
Svetlana Botsyun ◽  
Sebastian G. Mutz ◽  
...  
Keyword(s):  
Sea Level ◽  
Foreland Basin ◽  
European Alps ◽  
Molasse Basin ◽  
Central Alps ◽  
Pedogenic Carbonate ◽  
Northern Alpine Foreland ◽  
History Of ◽  
Alpine Foreland ◽  
Alpine Foreland Basin

Abstract. Reconstructing Oligocene–Miocene paleoelevation contributes to our understanding of the evolutionary history of the European Alps and sheds light on geodynamic and Earth surface processes involved in the development of Alpine topography. Despite being one of the most intensively explored mountain ranges worldwide, constraints on the elevation history of the European Alps remain scarce. Here we present stable and clumped isotope measurements to provide a new paleoelevation estimate for the mid-Miocene (∼14.5 Ma) European Central Alps. We apply stable isotope δ–δ paleoaltimetry to near-sea-level pedogenic carbonate oxygen isotope (δ18O) records from the Northern Alpine Foreland Basin (Swiss Molasse Basin) and high-Alpine phyllosilicate hydrogen isotope (δD) records from the Simplon Fault Zone (Swiss Alps). We further explore Miocene paleoclimate and paleoenvironmental conditions in the Swiss Molasse Basin through carbonate stable (δ18O, δ13C) and clumped (Δ47) isotope data from three foreland basin sections in different alluvial megafan settings (proximal, mid-fan, and distal). Combined pedogenic carbonate δ18O values and Δ47 temperatures (30±5 ∘C) yield a near-sea-level precipitation δ18Ow value of -5.8±1.2 ‰ and, in conjunction with the high-Alpine phyllosilicate δD value of -14.6±0.3 ‰, suggest that the region surrounding the Simplon Fault Zone attained surface elevations of >4000 m no later than the mid-Miocene. Our near-sea-level δ18Ow estimate is supported by paleoclimate (iGCM ECHAM5-wiso) modeled δ18O values, which vary between −4.2 ‰ and −7.6 ‰ for the Northern Alpine Foreland Basin.

scholarly journals Miocene high elevation and high relief in the Central Alps

2021 ◽  
Author(s):  
Emilija Krsnik ◽  
Katharina Methner ◽  
Marion Campani ◽  
Svetlana Botsyun ◽  
Sebastian G. Mutz ◽  
...  
Keyword(s):  
Sea Level ◽  
Foreland Basin ◽  
European Alps ◽  
Molasse Basin ◽  
Central Alps ◽  
Pedogenic Carbonate ◽  
Northern Alpine Foreland ◽  
History Of ◽  
Alpine Foreland ◽  
Alpine Foreland Basin

Abstract. Reconstructing Oligocene-Miocene paleoelevation contributes to our understanding of the evolutionary history of the European Alps and sheds light on geodynamic and Earth’s surface processes involved in the development of Alpine topography. Despite being one of the most intensively explored mountain ranges worldwide, constraints on the elevation history of the European Alps, however, remain scarce. Here we present stable and clumped isotope geochemistry measurements to provide a new paleoelevation estimate for the mid-Miocene (~14.5 Ma) European Central Alps. We apply stable isotope δ-δ paleoaltimetry on near sea level pedogenic carbonate oxygen isotope (δ18O) records from the Northern Alpine Foreland Basin (Swiss Molasse Basin) and high-Alpine phyllosilicate hydrogen isotope (δD) records from the Simplon Fault Zone (Swiss Alps). We further explore Miocene paleoclimate and paleoenvironmental conditions in the Swiss Molasse Basin through carbonate stable (δ18O, δ13C) and clumped (Δ47) isotope data from three foreland basin sections in different alluvial megafan settings (proximal, mid-fan, and distal). Combined pedogenic carbonate δ18O values and Δ47 temperatures (30 ± 5 °C) yield a near sea level precipitation δ18Ow value of −5.8 ± 0.2 ‰ and in conjunction with the high-Alpine phyllosilicate δD record suggest that the region surrounding the SFZ attained surface elevations of > 4000 m no later than the mid-Miocene. Our near sea level δ18Ow estimate is supported by paleoclimate (iGCM Echam5-wiso) modeled δ18O values, which vary between −4.2 and −7.6 ‰ for the Northern Alpine Foreland Basin.

scholarly journals Revealing exhumation of the central Alps during the Early Oligocene by detrital zircon U–Pb age and fission-track double dating in the Taveyannaz Formation

2020 ◽  
Vol 109 (7) ◽  
pp. 2425-2446
Author(s):  
Gang Lu ◽  
Maria Giuditta Fellin ◽  
Wilfried Winkler ◽  
Meinert Rahn ◽  
Marcel Guillong ◽  
...  
Keyword(s):  
Detrital Zircon ◽  
Fission Track ◽  
Foreland Basin ◽  
Late Eocene ◽  
Central Alps ◽  
Early Oligocene ◽  
Zircon Fission Track ◽  
Northern Alpine Foreland ◽  
Alpine Foreland ◽  
Alpine Foreland Basin

Abstract The late Eocene-to-early Oligocene Taveyannaz Formation is a turbidite series deposited in the Northern Alpine Foreland Basin (close to the Alpine orogenic front). Double dating of zircons with the fission-track and the U–Pb methods is applied on samples from the Taveyannaz Formation to reconstruct the exhumation history of the Central-Western Alps and to understand the syn-collisional magmatism along the Periadriatic lineament. Three samples from this unit show similar detrital zircon fission-track age populations that center at: 33–40 Ma (20%); 69–92 Ma (30–40%); and 138–239 Ma (40–50%). The youngest population contains both syn-volcanic and basement grains. Combined with zircon U–Pb data, it suggests that the basement rocks of Apulian-affinity nappes (Margna Sesia, Austroalpine) were the major sources of detritus, together with the Ivrea Zone and recycled Prealpine flysch, that contributed debris to the Northern Alpine Foreland Basin. Furthermore, the rocks of the Sesia–Lanzo Zone or of equivalent units exposed at that time presumably provided the youngest basement zircon fission-track ages to the basin. The Biella volcanic suite was the source of volcanogenic zircons. Oligocene sediment pathways from source to sink crossed further crystalline basement units and sedimentary covers before entering the basin from the southeast. The lag times of the youngest basement age populations (volcanic zircons excluded) are about 11 Myr. This constrains average moderate-to-high exhumation rate of 0.5–0.6 km/Myr in the pro-side of the orogenic wedge of the Central Alps during the late Eocene to early Oligocene.

scholarly journals Paleoenvironmental change recorded in submarine fans: the Eocene-Oligocene climate transition in the Alpine foreland basin

2021 ◽  
Author(s):  
Euan Soutter ◽  
Ian Kane ◽  
Ander Martínez-Doñate ◽  
Adrian Boyce ◽  
Jack Stacey ◽  
...  
Keyword(s):  
Environmental Change ◽  
Deep Water ◽  
Foreland Basin ◽  
Depositional Environments ◽  
Sediment Supply ◽  
Submarine Fan ◽  
Paleoenvironmental Change ◽  
Submarine Fans ◽  
Alpine Foreland ◽  
Alpine Foreland Basin

The Eocene-Oligocene transition (EOT) was a period of considerable environmental change, signifying the transition from Paleocene greenhouse to Oligocene icehouse conditions. Preservation of the sedimentary signal of such an environmental change is most likely in net-depositional environments, such as submarine fans, which are the terminal parts of sedimentary systems. Here, using sedimentological and stable isotope data from the Alpine foreland basin, we assess whether this major climatic transition influenced the stratigraphic evolution of submarine fans. Results indicate that submarine fan retreat in the Alpine foreland basin corresponds with positive δ13C excursions related to major global perturbations of the carbon cycle and cooling in the earliest Oligocene. Submarine fan retreat is suggested to be influenced by this cooling through enhanced aridity and reduced subaerial runoff from the Corsica-Sardinia hinterland. The influence of aridity was periodically overwhelmed by local environmental factors, such as hinterland uplift, which increased sediment supply to deep-water during arid periods. These results highlight that: 1) hinterland climate may play a greater role than sea-level in dictating sediment supply to deep-water and, 2) submarine fan evolution occurs through a complex interplay between climate, eustasy and tectonics, which makes robust interpretations of paleoenvironmental change from their stratigraphic record, without multi-proxy records, difficult.

scholarly journals Late Miocene thrusting in the North Alpine foreland: Driven by a deep-seated process and shaped by the local mechanical stratigraphy

2019 ◽  
Author(s):  
Samuel Mock ◽  
Christoph von Hagke ◽  
Fritz Schlunegger ◽  
István Dunkl ◽  
Marco Herwegh
Keyword(s):  
Late Miocene ◽  
Large Scale ◽  
Foreland Basin ◽  
Crustal Thickening ◽  
Tectonic Activity ◽  
European Alps ◽  
Strain Partitioning ◽  
Central Alps ◽  
The North ◽  
Alpine Foreland

Abstract. Besides classical emplacement and accretion related nappe tectonics, the Oligocene to middle Miocene post-collisional evolution of the central European Alps was also characterized by pronounced vertically directed tectonics. These are expressed by backthrusting along the Insubric Line and the subsequent uplift of the External Crystalline Massifs (ECMs). During late Miocene times, the Central Alps experienced lateral growth when deformation propagated into the external parts of both the pro- and retro-side of the orogen. For the North Alpine foreland, pro-wedge propagation of deformation has been kinematically and spatially linked to the uplift and exhumation of the ECMs. In this paper, we investigate the young exhumation history of the North Alpine foreland. Based on low-temperature apatite (U-Th-Sm)/He thermochronometry, we constrain thrusting in the Subalpine Molasse between 12 Ma and 5 Ma, thus occurring coeval to the main deformation phase in the adjacent Jura fold-and-thrust belt (FTB) and late stage exhumation of the ECMs. However, this pattern of tectonic activity is not restricted to areas which are bordered by the ECMs, but is consistent along the entire front of the Central Alps, regardless of its hinterland architecture. The local-scale pattern of strain partitioning and style of deformation is governed by lateral variations in the sedimentary foreland basin architecture. We suggest that the large-scale constant tectonic signal is the response to a shift in tectonic forces caused by a deep-seated geodynamic process. This resulted in a change from dominantly vertical to orogen-scale horizontal tectonics and an associated orogen-perpendicular growth of crustal thickening. We constrain the onset of this major tectonic change to ca. 15 Ma in the Southern Alps and ca. 12 Ma in the North Alpine foreland, where it results in (re-)activation of thrusts in the Subalpine Molasse and folding in the Jura FTB.

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