The Late Cretaceous calc-alkaline to alkaline plutons in the Central Anatolian crystalline complex are intrusive into metamorphic and ophiolitic rocks and mark a major magmatic pulse in the late Mesozoic evolution of the eastern Mediterranean region. We grouped the plutonic rocks with similar mineral and chemical compositions and inferred genetic relations into the granite, monzonite, and syenite supersuites. Granitic plutons mainly occur along the western edge of the Central Anatolian crystalline complex, whereas syenitic plutons form smaller bodies that crop out in the inner part. The granite supersuite is composed of granitic to granodioritic rocks, and the monzonite supersuite consists mainly of quartz monzonite and monzonitic rocks; both supersuites show enrichment in large-ion lithophile elements (LILE) and light rare earth elements (LREE) relative to high field strength elements (HFSE). The granitic-granodioritic rocks have compositions typical of high-K calc-alkaline and high-K shoshonitic series, whereas the monzonitic rocks display compositions characteristic of shoshonitic series. The syenite supersuite consists of quartz syenite, syenite, and nepheline- and pseudoleucite-bearing alkali rocks and shows more enrichment in LILE and a slight enrichment in HFSE compared to the other two supersuites. All three supersuite rocks have high 87 Sr/ 86 Sr and low 143 Nd/ 144 Nd ratios. These geochemical features suggest that the granite and monzonite supersuite magmas were derived from a subduction-modified and metasomatized mantle source and that the syenite supersuite magmas were derived from an enriched mantle source with considerable crustal contribution. New 40 Ar/ 39 Ar ages at 77.7 ± 0.3 Ma for the granite, 70.0 ± 1.0 Ma for the monzonite, and 69.8 ± 0.3 Ma for the syenite supersuite rocks indicate progressive evolution of the Central Anatolian crystalline complex magmatism from calc-alkaline to alkaline compositions with time. The latest Cretaceous emplacement of the complex's plutons and the chemical evolution of their magmas were syn-collisional in nature, after the leading edge of the Tauride platform collided with a trench in the Inner Tauride ocean and became partially subducted. Subsequent slab break-off resulted in asthenospheric upwelling and perturbation of the subduction-metasomatized lithospheric mantle that collectively produced the primary melts for the Central Anatolian crystalline complex plutons. These melts evolved through combined assimilation–fractional crystallization and mixing-mingling processes during their ascent and were affected by the interactions between mantle-derived and crustal-derived magmas. The late phases of this intracontinental magmatism were accompanied by tectonic extension of the thermally weakened orogenic crust in the Central Anatolian crystalline complex.

Abstract The Central Anatolian Crystalline Complex (CACC) or Kırşehir Block is part of the metamorphosed leading edge of the Tauride–Anatolide Carbonate Platform. It contains oceanic remnants derived from the Neotethys Ocean (İzmir–Ankara–Erzincan branch) which separate it from the Sakarya microcontinent. Two tectonic units are distinguished: an amphibolite facies Mesozoic ‘basement’, dominated by platform marbles, over which is thrust a younger fragmented Upper Cretaceous ophiolite sequence. Three metabasite horizons were sampled to reconstruct the development of the oceanic components: (1) fragmented Upper Cretaceous (90–85 Ma) stratiform ophiolitic members comprising gabbros, sheeted dykes, basalt lavas and pelagic sediments thrust over all other units; (2) a tectonised admixture of basite, ultramafic and felsic blocks in an ophiolitic mélange (Upper Cretaceous matrix) thrust over the basement metamorphic rocks; and (3) amphibolites concordant with ‘basement’ marbles and minor pelagics of the largely (?)Triassic Kaleboynu Formation in the lower part of the carbonate platform. Metabasalts and metagabbros from isolated fragments of the stratiform ophiolites form geochemically coherent groups and indicate the influence of a subduction component during their development. It is considered that the suprasubduction zone ophiolites record the association of a tholeiitic arc and an adjacent back-arc basin with more mid-ocean ridge basalt (MORB)-like compositions. Metabasite blocks within the tectonised ophiolitic mélange slice are MORB like, together with minor ocean island basalt (OIB) and island arc basalts, and may be tectonically related to ophiolitic units within the accretionary wedge of the Ankara Mélange. Concordant amphibolites of the Kaleboynu Formation are largely OIB types and reflect an early ensialic rifting stage of the Tauride–Anatolide Carbonate Platform. Small ocean basins also developed at this time, as recorded by the presence of MORB and associated pelagics. The CACC block, together with parts of the Ankara Mélange, are considered to represent oceanic lithosphere (comprising both early spreading centre and latter subduction-influenced crust) and continental carbonate platform that were subsequently ejected from an accretionary–subduction complex on collision with the Sakarya microcontinent.

Abstract The Central Anatolian crystalline region, comprising metasediments, ophiolitic slabs and numerous intrusives, has been called the Kırşehir Massif, the Kırşehir Block or Central Anatolian Crystalline Complex. Intrusive associations in Central Anatolia are summarized as: (1) a syncollisional, S (or C ST )-type, peraluminous and two-mica leuco-granitic association; (2) a post-collisional, I (or H LO )-type, metaluminous, high-K calcalkaline, typically K-feldspar megacrystic monzonitic association; and (3) an A-type, post-collisional and within-plate alkaline association comprising a high-K and silica-oversaturated alkaline, K-feldspar megacrystic monzonitic and synoptic subgroup, and a silica-undersaturated alkaline feldspathoid-sodalite syenite porphyry subgroup. Radiometric data suggest that metamorphism and magmatism in Central Anatolia were synchronous during the Late Cretaceous. This implies that metamorphism may have been generated by inverted metamorphism induced by the Anatolide-Pontide collision and was linked to a decreasing metamorphic grade from the north (i.e. from the main suture zone) towards the south (i.e. Taurides). Collision-related intrusive rocks within this crystalline body reflect differences in geological setting, mineralogical-chemical composition and associated ore deposition. Published data considering the distribution and timing of metamorphism and magmatism in the Central Anatolia suggest that both are related to the Anatolide-Pontide collision along the İzmir-Ankara-Erzincan Suture Zone in the Late Cretaceous. Various magmatic episodes affected along the passive margin of the Anatolides, including a syncollisional peraluminous episode, a post-collisional calc-alkaline hybrid and a post-collisional within-plate alkaline episode.

Abstract The calc-alkaline Karacaali Magmatic Complex (KMC), in the Central Anatolian Crystalline Complex, is an example of an Upper Cretaceous post-collisional I-type, plutonic–volcanic association. Volcanic rocks grade from basalt to rhyolite, whilst coeval plutonic rocks range from gabbro to leucogranite. In this paper we document evidence for the occurrence of both mixing and unmixing during the evolution of this igneous complex. Mixing of mafic and felsic magmas was observed in petrographic properties at microscopic to macroscopic scales and is further supported by mineral chemistry data. The occurrence of unmixing is evidenced in the Fe and Cu–Mo mineralization hosted in the KMC. The iron mineralization in basaltic-andesitic rocks consists mostly of magnetite. Magnetite has been grouped into four settings: (1) matrix type; (2) vein-filling type; (3) breccia matrix type; and (4) vesicle-filling type. In contrast, Cu–Mo mineralization is related to vertical north–south trending quartz-, quartz-calcite-, and quartz-tourmaline veins crosscutting monzonitic and granitic rocks. We propose that the intrusion of an oxidized, Fe- and Cu-rich basic magma into a partially crystallized acid magma resulted in partial mixing and may have triggered the abrupt separation of an iron-oxide-rich melt. Our results highlight the importance of magma mixing and metal unmixing, possibly associated with stress relaxation during post-collisional evolution. Supplementary material Electron microprobe analyses of plagioclase in monzonitic rocks, MMEs and electron microprobe analyses of K-feldspar in monzonitic rocks are available at http://www.geolsoc.org.uk/SUP18434 .