31-6 Salt structures in the Eastern External Betics fold and thrust belt, SE Iberia—Geologic maps, cross sections, and palinspastic reconstructions

Session: Best Student Geologic Map Competition (Posters)

Presenting Author:

Authors:

Abstract:

The Eastern External Betics fold and thrust belt, located in the southeastern corner of the Iberian Peninsula (Spain), is a system of ENE-trending cover folds and thrust sheets detached in Triassic evaporites. These Triassic evaporites (the Keuper facies) are incorporated into numerous diapirs most of which formed during the Jurassic to early Santonian extensional evolution of the southern Iberian passive margin. Contractional deformation began in the latest Cretaceous coinciding with the convergence of the African and Eurasian plates but is most pronounced during the middle to late Miocene. The present-day structure of Eastern External Betics is an ideal field area for examining inherited rift structures and extensional diapirism subject to inversion and shortening. The geologic maps and accompanying cross sections and reconstructions presented here show the evolution of these salt structures. We map and identify rejuvenated diapirs, thrust welds, secondary welds, tertiary welds, salt sheets, halokinetic fold ramps, secondary minibasins, and isolated carapace fragments that formed during the contractional evolution of the fold and thrust belt. We provide a high-resolution analysis of diapiric growth, which started shortly after salt deposition in the Early Jurassic and constrain the timing of allochthonous salt breakout and its evolution alongside the building of the Betic fold and thrust belt. Our detailed field work showcases the diverse nature of salt related structures in the Eastern External Betics depicting how structural inheritance of the passive margin system played a key role in controlling the contractional evolution of the fold and thrust belt.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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