The cooling, deformation and exhumation history of the late Miocene syn-tectonic Porto Azzurro pluton in a regional transfer zone (Elba Island, Italy)

2020 ◽  
Author(s):  
Andrea Brogi ◽  
Richard Spiess ◽  
Alfredo Caggianelli ◽  
Antonio Langone ◽  
Fin Stuart ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Northern Apennines ◽  
Contact Metamorphism ◽  
Pluton Emplacement ◽  
Vertical Permeability ◽  
Extensional Tectonic ◽  
History Of ◽  
Elba Island ◽  
Exhumation History ◽  
Transfer Zone

<p>In extensional tectonic settings, stretched terrains are often associated to lithosphere partial melting and widespread magmatism with plutons emplaced in the thinned crust. Emplacement of felsic magmas, at upper crustal levels, represents the final stage of the magma transfer from profound to shallow depth. In this framework, a mostly vertical permeability controls the magma uprising migration, as induced by dominant transcurrent crustal structures. Nevertheless, the interplay between extension and prolonged heat transfer favors uplift and progressive exhumation of the magmatic bodies, during their cooling.</p><p>In this presentation, we show an example of a felsic magmatic intrusion, the Porto Azzurro pluton (inner northern Apennines), emplaced in an extensional tectonic setting and mainly controlled by a regional transfer zone related to the opening of the Tyrrhenian Basin. This is exposed in the eastern Elba Island (Tuscan Archipelago). The hosting rocks of the Porto Azzurro pluton are mainly represented by micaschist, paragneiss and quartzite, affected by contact metamorphism and intense fluid circulation. We have analysed the structures that assisted the pluton emplacement and the ones that deformed the pluton itself during its cooling, from melt-present to brittle conditions, based on the integration among fieldwork, micro-structural, petrological and EBSD analyses. Furthermore, new U/Pb geochronological data on zircons and (U-Th)/He on apatite fission track refined the age of the pluton emplacement and its cooling, adding new data about the pluton history. Existing petrological analyses of the hosting rocks allowed us to better constrain the time-evolution of the thermal perturbation, permitting to frame the deformation and exhumation history of the Porto Azzurro monzogranite in the context of the Neogene extensional tectonics affecting the inner Northern Apennines.</p>

scholarly journals Comment on ‘Unveiling ductile deformation during fast exhumation of a granitic pluton in a transfer zone’ by Richard Spiess, Antonio Langone, Alfredo Caggianelli, Finlay M. Stuart, Martina Zucchi, Caterina Bianco, Andrea Brogi, & Domenico Liotta

2021 ◽  
Author(s):  
Francesco Mazzarini ◽  
Giovanni Musumeci ◽  
Samuele Papeschi
Keyword(s):  
Tectonic Setting ◽  
Horizontal Displacement ◽  
Northern Apennines ◽  
Ductile Deformation ◽  
Upper Crust ◽  
Small Section ◽  
Granitic Pluton ◽  
Thermal Peak ◽  
Ebsd Data ◽  
Transfer Zone

In their paper, Spiess et al. (2021) published structural, geochronological, and EBSD data on one of the monzogranite apophyses (Capo Bianco) of the buried Porto Azzurro Pluton (island of Elba, Northern Apennines, Italy), a pluton emplaced in the upper crust (P < 0.2 GPa; e.g. Papeschi et al., 2019). The authors publish a new U/Pb age of 6.4 ± 0.4 Ma, associated to the thermal peak, and a U-Th/He apatite age of 5.0 ± 0.6 Ma, related to a T of 60 °C. Spiess et al. (2021) use these ages to model the exhumation of the pluton controlled by the sub-horizontal Zuccale Fault, a fault with 6 km of horizontal displacement (ZF; Keller & Coward, 1996). Their structural dataset from the macro to the microscale and EBSD analyses relies on a small section (about 100 m wide) in the NE part of the Calamita Peninsula. Based on their documentation of (1) vertical dykes in the monzogranite, (2) vertical to low-angle top-to-the-E extensional faults, and (3) later NW-striking oblique faults, they interpret the Porto Azzurro Pluton as emplaced in an extensional to transcurrent tectonic setting, extrapolating their findings to the entire Eastern Elba.

scholarly journals Burial-deformation History of Folded Rocks Unraveled by Fracture Analysis, Stylolite Paleopiezometry and Vein Cement Geochemistry: A Case Study in the Cingoli Anticline (Umbria-Marche, Northern Apennines)

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 135
Author(s):  
Aurélie Labeur ◽  
Nicolas E. Beaudoin ◽  
Olivier Lacombe ◽  
Laurent Emmanuel ◽  
Lorenzo Petracchini ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Central Italy ◽  
Microstructural Analysis ◽  
Northern Apennines ◽  
Foreland Basins ◽  
Deformation History ◽  
The North ◽  
Regional Tectonic ◽  
History Of ◽  
Clumped Isotope

Unravelling the burial-deformation history of sedimentary rocks is prerequisite information to understand the regional tectonic, sedimentary, thermal, and fluid-flow evolution of foreland basins. We use a combination of microstructural analysis, stylolites paleopiezometry, and paleofluid geochemistry to reconstruct the burial-deformation history of the Meso-Cenozoic carbonate sequence of the Cingoli Anticline (Northern Apennines, central Italy). Four major sets of mesostructures were linked to the regional deformation sequence: (i) pre-folding foreland flexure/forebulge; (ii) fold-scale layer-parallel shortening under a N045 σ1; (iii) syn-folding curvature of which the variable trend between the north and the south of the anticline is consistent with the arcuate shape of the anticline; (iv) the late stage of fold tightening. The maximum depth experienced by the strata prior to contraction, up to 1850 m, was quantified by sedimentary stylolite paleopiezometry and projected on the reconstructed burial curve to assess the timing of the contraction. As isotope geochemistry points towards fluid precipitation at thermal equilibrium, the carbonate clumped isotope thermometry (Δ47) considered for each fracture set yields the absolute timing of the development and exhumation of the Cingoli Anticline: layer-parallel shortening occurred from ~6.3 to 5.8 Ma, followed by fold growth that lasted from ~5.8 to 3.9 Ma.

Thermochronology and exhumation history of the basement and sediments of the NNE border of the Paraná basin, Brazil

2020 ◽  
Vol 99 ◽  
pp. 102512 ◽  
Author(s):  
Rosana Silveira Resende ◽  
Carlos Alberto Tello Sáenz ◽  
Elton Luiz Dantas ◽  
Peter Christian Hackspacher ◽  
César Anthony Chavez Machaca ◽  
...  
Keyword(s):  
History Of ◽  
Paraná Basin ◽  
Parana Basin ◽  
Exhumation History
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