Late Cretaceous-Palaeocene subduction-collision-exhumation of a microcontinent along the northern, active margin of the Southern Neotethys: Evidence from the Alanya Massif and the adjacent Antalya Complex (S Turkey)


Robertson A. H. F. , PARLAK O.

JOURNAL OF ASIAN EARTH SCIENCES, cilt.201, 2020 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

The Alanya Massif represents a microcontinent that underwent subduction/exhumation related to collision with the larger Tauride microcontinent to the north during latest Cretaceous-Palaeocene. Intermediate-structurallevel blueschist melange in the northwest (Gundogmus area) encompasses ductile-deformed meta-basaltic rocks, meta-cherts and minor serpentinite in a lower-grade meta-mudrock matrix. The meta-basaltic protoliths mainly formed in a subduction-influenced setting, together with less common OIB and E-MORB. Late Permian platform/ slope carbonates were intersliced during late-stage brittle thrusting and directly over-ridden by a lower-grade (greenschist facies) Late Permian-Early Triassic-aged platform unit. The blueschist melange is interpreted as an oceanic subduction complex that was obducted southwards related to microcontinental collision. Intermediatestructural-level HP/LT blueschist-ecologites farther south (Alanya area) indicate that the Alanya Massif represents variably subducted/exhumed continental crust. Both subduction and exhumation took place during the latest Cretaceous, prior to Late Palaeocene-Early Eocene marine transgression. Late Precambrian protoliths of eclogitic HP/LT rocks, and also similar-aged amphibolite facies meta-basic intrusions farther southeast (Anamur area) are interpreted to have formed in a Panafrican (Cadomian) late-stage back-arc setting. Late Triassic basaltic rocks in the Antalya Complex (structurally beneath and to the north) erupted in a rift setting. We restore the Mesozoic palaeogeography from north to south as: Tauride microcontinent-Antalya rift basin-Alanya micrcontinent-S Neotethys. The subduction/exhumation history may serve as a model for similar active margin/collisional settings elsewhere.