"S-N profiles of the principal 3D layers in the model seen from the east. Top: Reconstructed detachment surface (polygonised blue) draping over the marble (purple), schist (light blue), migmatite core (yellow), granodiorite (orange) and S-type granite (red). All layers are extended above the topography. Bottom: Detachment surface (polygonised blue) cuts the reconstructed metamorphic isograds. Isograd layers are: +Corundum (brown), +Biotite (green), -Chloritoid (orange), +Sillimanite (turquoise), -Kyanite (purple) and +Melt (red). Scale is ~43x6 km, note compasses in the bottom right.”
Supervisor: Professor Uwe Ring

Time and date: Januari 14, 2016, 13.30

Place: Y22, Geohuset (link to the house plan)

Abstract
3D Modeling of the island of Naxos was undertaken with data from published and own sources. A simplified, geometrically correct and geologically feasible 3D structural model of the island was produced. Special emphasis was put on constraining the geometry of the Naxos/Paros detachment, which is only sparingly exposed in the east and west, and its relation to documented metamorphic boundaries in three dimensions. N-S regional extension is estimated to ~35% and local extension associated with the Naxos/Paros detachment is calculated to ~83%, implying a local E-W shortening of ~45% is needed to maintain constant crustal volume. Regionally this E-W shortening is estimated to ~26%. From the 3D model, late E-W shortening contemporaneous with the N-S extension in the Miocene was calculated to be ~7–10%. The results show that the magnitude of E-W shortening since the early Miocene is not enough to explain the current crustal thickness. An argument for localized extension correlating with the Naxos MCC and a heterogeneous N-S stretching of the lithosphere is made on account of the extension/shortening calculated, implied mass imbalance, Moho topography and similarities with the Basin and Range province. Geometric relationships between the detachment and metamorphic isograds are presented in 2- and 3D and an attempt was made to identify and quantify fault displacement in the field to constrain the model. Possible duplexes, related to the early subduction stage and high-pressure metamorphism, were also found on the southeast coast of the island.

     

 

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