Metamorphic sole formation, emplacement and blueschist facies overprint: early subduction dynamics witnessed by western Turkey ophiolites
Abstract
The largest ophiolite on Earth, in western Turkey, is a key place
to study obduction and early subduction dynamics. Ophiolite
remnants derived from the same Neotethyan branch (preserved
as a result of long-lived Late Cretaceous continental subduction
and later obduction) are underlain by hundred-metre-thick
extensive metamorphic soles. These soles formed syn-
chronously, at c. 93 Ma, and were welded to the base of the
ophiolite, thereby dating the start of intra-oceanic subduction.
This contribution focuses on the structure, petrology and pres-
sure–temperature evolution of the soles and other subduction-
derived units. Peak pressure–temperature conditions were esti-
mated at 10.5 2 kbar and 800 50 °C for the sole by
means of pseudosection calculations using Theriak/Domino and
at 12 kbar and 425 °C for the unique, enigmatic blueschist
facies overprint of the sole. This study provides clues to the
mechanisms of sole underplating during early subduction, later
cooling, and the nature of the western Turkey ophiolite.