Casetta, F.

Coltorti, M

Giacomoni, P.

Nardini, N.

English

Casetta F.

Giacomoni P.

Nardini N.

Coltorti M

Archivio istituzionale della ricerca - Università di Ferrara

EGU2020-18258https://doi.org/10.5194/egusphere-egu2020-18258EGU General Assembly 2020© Author(s) 2021. This work is distributed underthe Creative Commons Attribution 4.0 License.How to reconstruct the geometry of a Middle Triassic feedingsystem: clues from clinopyroxene textures in lava flows from CimaPape (Southern Alps, Italy)Federico Casetta, Pier Paolo Giacomoni, Nicolò Nardini, and Massimo ColtortiDepartment of Physics and Earth Sciences, University of Ferrara, Ferrara, Italy (cstfrc@unife.it)Ancient volcano-plutonic complexes can record the evolution of single- or multi-pulse plumbingsystems and thus can be used as proxy to investigate the magma dynamics beneath activevolcanoes. The exceptional state of conservation of the Middle Triassic Cima Pape complex(Dolomitic Area, Southern Alps) makes it an ideal snapshot of a ~238 Ma old feeding system of adominantly effusive volcano. It is composed of a 50 to 300 metres thick gabbroic to monzodioriticsill intruded in the sedimentary cover and overlaid by its volcanic counterpart, made up of basalticto trachyandesitic lavas and pillow breccias. A detailed investigation of the textural andcompositional features of clinopyroxene phenocrysts in the volcanites revealed that complexdynamic processes took place in the feeding system beneath the Cima Pape “volcano”. Althoughsome crystals have normal homogeneous or simple-zoned texture, with Mg# [MgO/(MgO+FeOtot)mol%] ranging between 71 and 77 (type 1 clinopyroxene), the great majority of them is typified bya peculiar texture, characterized by the occurrence of intermediate high-Mg# (80-84, up to 90),high-Cr2O3(up to 1.0 wt%) and low-TiO2(down to 0.1 wt%) bands (type 2 clinopyroxene). Theseovergrowths, crystallized between low-Mg# cores and rims, likely indicate that the feeding systemwas affected by frequent mixing between mafic inputs and differentiated batches. An overview ofthe main textural/geochemical features of clinopyroxene in effusive and intrusive products wasput forward in the present study to reconstruct the main chemico-physical parameters andevolution of the feeding systems beneath the Middle Triassic volcanoes of the Dolomitic Area.Afterwards, these results will be used to advance some speculations about the processes recordedby clinopyroxene crystals in lava flows from active volcanoes, such as Stromboli and/or Mt. Etna.Powered by TCPDF (www.tcpdf.org)

How to reconstruct the geometry of a Middle Triassic feeding system: clues from clinopyroxene textures in lava flows from Cima Pape (Southern Alps, Italy)

https://iris.unife.it/bitstream/11392/2419394/2/EGU2020-18258-print.pdf

How to reconstruct the geometry of a Middle Triassic feeding system: clues from clinopyroxene textures in lava flows from Cima Pape (Southern Alps, Italy)

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Archivio istituzionale della ricerca - Università di Ferrara