Hafnium isotopic record of mantle-crust interaction in an evolving continental magmatic system

Magmatic Processes at Snæfell Volcano, Iceland, Constrained by Zircon Ages, Isotopes, and Trace Elements

“…(2020) demonstrate that mantle flux plays a key role in determining whether mantle melt or crustal contamination dominates in silicic petrogenesis. Early basaltic intrusions into the crust may cause only limited melting and assimilation but ensuing magma injections into progressively hotter crust might result in more extensive partial melting and assimilation of crustal material with time (Storck et al., 2020). If this model is applied to Snæfell, the slightly elevated zircon ε Hf values in the young grains from IESn3 would result from crystallization in rhyolite derived from a higher fraction of anatectic melts from high‐ε Hf crust relative to older samples IESn1 and IESn2.…”

“…Storck et al. (2020) demonstrate that mantle flux plays a key role in determining whether mantle melt or crustal contamination dominates in silicic petrogenesis. Early basaltic intrusions into the crust may cause only limited melting and assimilation but ensuing magma injections into progressively hotter crust might result in more extensive partial melting and assimilation of crustal material with time (Storck et al., 2020).…”

Mantle-derived Corundum-bearing Felsic Dykes May Survive Only within the Lower (refractory/inert) Crust: Evidence from Zircon Geochemistry and Geochronology (Ivrea-Verbano Zone, Southern Alps, Italy)

“…Important igneous events mark the geodynamic evolution of the area now referred to the Southern Alps during Triassic times. In particular, a diffuse igneous activity with orogenic, shoshonitic to K-rich calc-alkaline, affinity developed during the Middle Triassic (~243-235 Ma) in the Eastern (Dolomites area) and Central (Brescian PreAlps) sectors ( [127,128,129,130,131,132]. These events occurred under mainly transtensional regime, which determined the partial melting of mantle regions metasomatised by crustal components during the Variscan orogenic cycle [129,130,131].…”

“…These events occurred under mainly transtensional regime, which determined the partial melting of mantle regions metasomatised by crustal components during the Variscan orogenic cycle [129,130,131]. In the westernmost sector of the Southern Alps, the record of this tectono-magmatic activity is poorly documented, being essentially limited to Ladinian-Carnian ages provided by magmatic (e.g., 239-232 Ma; [60,63,133]) and metamorphic zircons, e.g., [134,135] from the deepest crustal rocks of IVZ, namely those of the Finero Complex, and by zircons from tuffitic layers occurring in the carbonate platform (241 Ma; [132,136]). Alkali-rich magmatism with orogenic character similar to that of Middle Triassic lavas and intrusives of Dolomites has been documented in the Finero Complex by Giovanardi et al, [137].…”

Mantle-Derived Corundum-Bearing Felsic Dykes May Survive Only within the Lower (Refractory/Inert) Crust: Evidence from Zircon Geochemistry and Geochronology (Ivrea–Verbano Zone, Southern Alps, Italy)

“…Important igneous events mark the geodynamic evolution of the area now referred to the Southern Alps during Triassic times. In particular, a diffuse igneous activity with orogenic, shoshonitic to K-rich calc-alkaline, affinity developed during the Middle Triassic (~243-235 Ma) in the Eastern (Dolomites area) and Central (Brescian PreAlps) sectors ( [127][128][129][130][131][132]). These events occurred under mainly trans-tensional regime, which determined the partial melting of mantle regions metasomatized by crustal components during the Variscan orogenic cycle [129][130][131].…”