New mineralogic data and implications for the tectonometamorphic evolution of the Alanya nappes, Central Tauride Belt, Turkey
Abstract
The Alanya Unit, consisting of three nappes, crops out in the Demirtas-Anamur area of the Tauride Belt and is related to the Alpine orogeny. The Mahmutlar nappe of Permian and pre-Permian age progressively evolved as indicated by 2M(t) white K-mica, Mg-chlorite, and 1M biotite which are related to increasing metamorphism from its upper (phyllite, metasiltstone) to lower parts (biotite schist, staurolite-kyanite-garnet-mica schist). The b values of the white K-micas are characterized by a facies series of medium- to high-pressure metamorphism. The Sugozii nappe comprises garnet-mica schist with metabasite (eclogite, glaucophane schist) interbands and/or lenses composed of muscovite, chlorite, and rarely paragonite and illite-smectite. The crystallinity and b values of phengitic micas in the metapelites represent epizonal and medium-pressure facies conditions. The Yumrudag nappe of Pre-Permian-Triassic age is characterized by index minerals, such as chloritoid, paragonite, kaolinite/dickite, 1Te pyrophyllite, and margarite. Epizonal 2M(l) white K-micas with low b values indicate lower-pressure metamorphism. The mineralogic and geochemical signatures of these metasedimentary rocks indicate that the nappes were predominantly derived from different sources. The Mahmutlar nappe developed under a Barrovian-type regional dynamothermal progressive metamorphism. The Sugozu nappe records an earlier high-pressure/low-temperature metamorphism that has been overprimed-together with the structurally overlying Mahmutlar nappe-by a later Barrovian metamorphic event. The Yumrudag nappe, on the other hand, is characterized by a metamorphic evolution with a typical counterclock-wise P-T-t path in an extensional basin, such as those of the northern allochthonous Tauride units, indicating that its southward emplacement onto the other nappes was relatively late.
Source
INTERNATIONAL GEOLOGY REVIEWVolume
46Issue
4Collections
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