Estimating P-T metamorphic conditions on the roof of a hidden granitic pluton: an example from the Mt. Calamita promontory (Elba Island, Italy)

The lawsonite-glaucophane blueschists of Elba Island (Italy)

“…(d) The metabasites record a retrograde evolution, without significant deformation, under greenschistfacies conditions, and then underwent a LP heating episode attributable to the intrusion of the Porto Azzurro monzogranite (Caggianelli et al, 2018). The exhumation to the retrograde evolution occurred during the middle Miocene, being consecutive to the collision and preceding the monzogranite intrusion (~ 6.5 Ma).…”

Interactions of plutons and detachments: a comparison of Aegean and Tyrrhenian granitoids

“…The Porto Azzurro pluton, more recently, induced the formation of a high-temperature contact metamorphism in the Calamiti schists cropping out underneath the Zuccale Fault. Estimations of the pressure-temperature (P -T ) conditions of this metamorphism suggest that the pluton was emplaced at a similar depth of about 6.5 km and the maximum temperature recorded in the schists is about 650 • C fringing the muscovite breakdown reaction (Caggianelli et al, 2018;Rochira et al, 2018). Analysis of the metamorphic aureole also reveals multiple hydrofracturing episodes by boron-rich fluids which can be compared to the present-day fluid circulation at depth in the Larderello geothermal field (Dini et al, 2002(Dini et al, , 2008.…”

Fluid‐Assisted Strain Localization in Quartz at the Brittle/Ductile Transition

“…The structural evolution, controlled in first order by the decreasing temperature during deformation, is conceptually summarized in Figure 9. At relatively high metamorphic-grade conditions (amphibolite facies; Caggianelli et al, 2018;Musumeci & Vaselli, 2012) quartz recrystallized producing stretched mylonitic ribbons (Figure 9a). 5.2 and 5.3.…”

“…The Calamita Schists, part of the Calamita Unit (Figure 1a), are an amphibolite facies metapsammitic complex that crop out in SE Elba Island (Barberi et al, 1967). These rocks experienced Miocene deformation and LP/HT metamorphism triggered by the intrusion of the buried Porto Azzurro pluton (Papeschi et al, 2017) with peak temperatures around 625°C (Caggianelli et al, 2018) or exceeding 650°C (Musumeci & Vaselli, 2012) at pressure lower than 0.2 GPa (Duranti et al, 1992). Deformation, related to the activity of thrust sheets coeval with pluton emplacement, affected the Calamita Schists at upper crustal conditions during postmagmatic cooling.…”

“…5.2 and 5.3. At relatively high metamorphic-grade conditions (amphibolite facies; Caggianelli et al, 2018;Musumeci & Vaselli, 2012) quartz recrystallized producing stretched mylonitic ribbons (Figure 9a). Deformation concentrated in first order in recrystallized portions, leaving behind large quartz porphyroclasts, where dislocation creep was recorded as intracrystalline…”