Emplacement modes of the Ladinian plutonic rocks of the Dolomites: Insights from anisotropy of magnetic susceptibility

Abbas, Hassan; Michail, Maria; Cifelli, Francesca; Mattei, Massimo; Gianolla, Piero; Lustrino, Michele; Carminati, Eugenio

doi:10.1016/j.jsg.2018.05.012

Cited by 27 publications

(10 citation statements)

References 76 publications

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“…This magmatism has been associated either to compressional, extensional and/or transtensional geodynamics (e.g. Crisci et al 1984;Castellarin et al 1988;Sloman, 1989;Bonadiman et al 1994;Armienti et al 2003;Csontos & Vörös, 2004;Beccaluva et al 2005;Doglioni & Carminati, 2008;Schmid et al 2008;Zanetti et al 2013;Abbas et al 2018;Bianchini et al 2018;Casetta et al 2018b;Storck et al 2019). Such contrasting interpretations are probably due to (1) the palaeogeographic position of the outcrops (at the edge between Gondwana and Laurasia), for which palinspastic reconstructions are still debated (e.g.…”

Section: Introductionmentioning

confidence: 99%

Triassic magmatism in the European Southern Alps as an early phase of Pangea break-up

et al. 2020

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Magmatic rocks from the Dolomites, Carnic and Julian Alps, Italy, have been sampled to investigate the origin and geodynamic setting of Triassic magmatism in the Southern Alps. Basaltic, gabbroic and lamprophyric samples have been characterized for their petrography, mineral chemistry, whole-rock major and trace elements, and Sr, Nd and Pb isotopic compositions. Geothermobarometric estimates suggest that the basaltic magmas crystallized mostly at depths of 14–20 km. Isotopic data show variable degrees of crustal contamination decreasing westwards, probably reflecting a progressively more restitic nature of the crust, which has been variably affected by melting during the Permian period. Geochemical and isotopic data suggest that the mantle source was metasomatized by slab-derived fluids. In agreement with previous studies and based on geological evidence, we argue that this metasomatism was not contemporaneous with the Ladinian–Carnian magmatism but was related to previous subduction episodes. The lamprophyres, which likely originated some 20 Ma later by lower degrees of melting and at higher pressures with respect to the basaltic suite, suggest that the mantle source regions of Triassic magmatism in the Dolomites was both laterally and vertically heterogeneous. We conclude that the orogenic signatures of the magmas do not imply any coeval subduction in the surrounding of Adria. We rather suggest that this magmatism is related to the Triassic rifting episodes that affected the western Mediterranean region and that were ultimately connected to the rifting events that caused the break-up of Pangea during the Late Triassic – Early Jurassic period.

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Section: Introductionmentioning

confidence: 99%

Triassic magmatism in the European Southern Alps as an early phase of Pangea break-up

et al. 2020

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“…11g-h). The syn-magmatic dike swarms, cropping out at the intrusion area, appear to cut the deformed sedimentary country rocks and intrude the magmatic edifice (Sloman 1989;Bonadiman et al, 1994;Gianolla et al, 2010;Abbas et al, 2018) while the pluton carries a NE-SW striking apophysis that trails the intrusion at its SW boundary. Similar natural examples of syn -tectonic emplacement mode are: 1) The Mortagne pluton (Román-Berdiel et al, 1997); 2) The Los Pedroches pluton (Aranguren et al, 1997;Román-Berdiel et al, 2000); 3) The Jihlava Intrusion (Verner et al, 2006); 4) The Hombreiro pluton (Román-Berdiel et al, 2000); 5) The Gulf of Aden Ridge (Corti et al, 2003).…”

Section: Natural Examples For Intrusion Into Transtensional Shear Zonesmentioning

confidence: 99%

Shape of plutons in crustal shear zones: A tectono-magmatic guide based on analogue models

Michail¹,

Rudolf²,

Rosenau³

et al. 2022

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Plutons in crustal shear zones may exploit inherited structures, interfere with strain localizing or be deformed passively. To constrain the relative timing of such tectono-magmatic constellations in natural settings is not always straightforward. We here present sandbox-type analogue model experiments simulating magma emplacement into simple and transtensional crustal shear zones to test the diagnostic potential of pluton shape with respect to timing and setting. Observations based on surface deformation and intrusion shape exemplify the interplay between evolving and inherited tectonic structures and magma uprising. We observe markedly asymmetric intrusions in association with dikes reflecting the regional stresses, fault pattern and finite strain field. At the same time, the presence of an intrusion modifies the tectonic evolution, but only transiently, resulting in short-lived faults, reactivation and inversion. Diagnostic attributes include the pluton's aspect ratio, its orientation and amplitude as well as dike association. Accordingly, syn-tectonic intrusions show the highest pluton amplitudes and intermediate elongation oriented parallel to between Riedel shears in simple shear, and compression in transtension. Post-tectonic intrusions are least elongated but relatively high and exploit Riedel shears. Pre-tectonic intrusions are characterized by low amplitudes and high aspect ratios parallel to the finite elongation direction. Intrusions in transtensional shear zones are generally of lower amplitude th an those in simple shear zones. Experimental results are tested against observations from natural examples validating the di agnostic potential of pluton shape for the timing and the tectonic setting of the emplacement.

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“…The Triassic magmatism affected a continental area which at the time confined with the western Tethys, and comprised the 90 Southalpine, Dinaric, Transdanubian and Austral-alpine domains (Abbas et al, 2018). In the Dolomites the magmatic rocks are rare pyroclastics, dykes, sills, subaerial and marine volcanics, next to intrusives found at Predazzo and at Monti Monzoni.…”

Section: Triassic Magmatismmentioning

confidence: 99%

“…The origin of the magmatism has been hypothesized as due to a plume, subduction, or extensional events at lithospheric scale (Abbas et al, 2018;Casetta et al, 2018). The magmatism could be associated to activation of regional strike-slip faults during the Ladinian (Abbas et al, 2018). In comparison with the Paleozoic magmatic event, the Triassic magmatic volume appears 95 to be more modest and characterized by a stronger abundance of basic and intermediate products.…”

Section: Triassic Magmatismmentioning

confidence: 99%

Gravity modeling of the Alpine lithosphere affected by magmatism based on seismic tomography

Tadiello¹,

Braitenberg²

2020

Preprint

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Abstract. The Southern Alpine regions have been affected by several magmatic and volcanic events between the Paleozoic and the Tertiary. This activity has undoubtedly had an important effect on the density distribution and structural setting at lithosphere scale. Here the gravity field is used to create a 3D lithosphere density model on the base of a high-resolution seismic tomography model. The results of the gravity modelling demonstrate a highly complex density distribution in good agreement with the different geological domains of the Alpine area represented by the European plate, the Adriatic plate and the Tyrrhenian basin. The Adriatic derived terrains (Southalpine and Austrolpine) of the Alps are typically denser (2850 kg m−3), whilst the Alpine zone composed by European terrains provenance (Helvetic and Tauern window) presents lower density values (2750 kg m−3). Inside the Southalpine, south of the Dolomites, a well-known positive gravity anomaly is present and one of the aims of this work is to investigate the source of this anomaly that has not yet been explained. The modelled density suggests that the anomaly is related to two different sources, the first involves the middle-crust below the gravity anomaly and is represented by localized mushroom-shaped bodies interpreted as a magmatic intrusion, while a second wider density anomaly affects the lower crust of the Southern Alpine realm and could correspond to a mafic and ultramafic magmatic underplating (gabbros and related cumulates) developed during Paleozoic extension.

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Emplacement modes of the Ladinian plutonic rocks of the Dolomites: Insights from anisotropy of magnetic susceptibility

Cited by 27 publications

References 76 publications

Triassic magmatism in the European Southern Alps as an early phase of Pangea break-up

Triassic magmatism in the European Southern Alps as an early phase of Pangea break-up

Shape of plutons in crustal shear zones: A tectono-magmatic guide based on analogue models

Gravity modeling of the Alpine lithosphere affected by magmatism based on seismic tomography

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