Abstract

New ⁴⁰Ar/³⁹Ar, U–Pb, and Sm–Nd data from 13 metamorphic samples constrain the formation and exhumation of the high-pressure Maksyutov Complex in the southern Uralide orogen. The Maksyutov Complex records the highest-pressure metamorphism in the southern Uralides, and is part of the thrust stack that composes the footwall beneath the Main Ural Fault. The new isotopic data from eclogite in the Lower Unit of the Maksyutov Complex include ⁴⁰Ar/³⁹Ar data from phengite, U–Pb data from rutile and apatite and Sm–Nd data from garnet, clinopyroxene, rutile and apatite. These data indicate that eclogite–facies metamorphism occurred in the Mid-Devonian Epoch (c. 380 Ma), corresponding with eastward subduction of the East European craton beneath the Magnitogorsk island arc. After partial exhumation, the Lower unit was juxtaposed c. 360 Ma (based on ⁴⁰Ar/³⁹Ar white mica data) with the Middle and Upper units at mid-crustal levels during the development of a D₃ shear zone within the subduction zone. By the Late Carboniferous Epoch, the Maksyutov Complex was exhumed to upper-crustal levels, compatible with sedimentologic evidence that at this time the foreland thrust and fold belt began to form, and material was shed off it into the foreland basin.