Evolution and genesis of calc-alkaline magmas at the Paphsanias Volcanic Field, Aegean Arc

Günther T, Wölki D, Storch B, Beier C, Haase K (2018)

Publication Type: Conference contribution, Abstract of a poster

Publication year: 2018

Event location: Bonn

Abstract

The Aegean arc is one of the arcs with the highest rate of sediment subduction and ~8 km of sediment are found in the Hellenic Trench. In 1984, the submarine Paphsanias Volcanic Field was discovered west of the islands of Methana and Aegina, the two major westernmost volcanic centers of the Aegean Arc. The Paphsanias Volcanic Field consists of six volcanic structures ranging from massive lava flows to relatively complex volcanic structures with heights of 300 m. These volcanic structures represent an early stage of submarine volcanism of the Aegean arc volcanoes. Four of the Paphsanias volcanic structures were sampled during the Pos512 cruise in 2017 and here we discuss the preliminary petrological and geochemical data of ~100 samples with basaltic to andesitic compositions.

The basis of two of the Paphsanias volcanic structures consist of basaltic lava flows with 10 to 7 wt.% MgO and 150 to 80 ppm Ni, whereas the shallower flows and lava domes have andesitic compositions. Here, we suggest that most andesites are generated by either fractional crystallization or magma mixing between mafic and silicic melts during replenishment of shallow crustal magma reservoirs. The Paphsanias basalts are more mafic than lavas from neighboring Methana but also than known mafic lavas form other Aegean volcanoes. Iron and Ti contents of the Paphsanias and Methana lavas follow the same calc-alkaline trend. However, one of the submarine volcanoes shows V contents that overlap with the tholeiitic trend of lavas from Santorini which may reflect a change in state of  redox state of the Paphsanias Volcanic Field. 

Compared to Santorini, ratios of Ba/Nb, Nb/Zr and Zr/Y are more enriched and probably indicate different degrees of partial melting, enrichment of the mantle source, and/or variable crust addition.

Authors with CRIS profile

How to cite

APA:

Günther, T., Wölki, D., Storch, B., Beier, C., & Haase, K. (2018). Evolution and genesis of calc-alkaline magmas at the Paphsanias Volcanic Field, Aegean Arc. Poster presentation at GeoBonn2018, Bonn, DE.

MLA:

Günther, Thomas, et al. "Evolution and genesis of calc-alkaline magmas at the Paphsanias Volcanic Field, Aegean Arc." Presented at GeoBonn2018, Bonn 2018.

BibTeX: Download