HR: 0800h
AN: T11C-0401    [Abstracts]
TI: Geological, Geochemical Characteristics and Tectonic Significance of Mafic and Ultramafic Rocks in the Northeast Segment of Antalya Complex, SW Turkey
AU: * Elitok, O
EM: oelitok@mmf.sdu.edu.tr
AB: The area of SW Turkey known as the Isparta Angle include autochthonous and allochthonous units (from west to east the Lycian nappes, Beydaglari-Karacahisar autochthonous, the Antalya Complex, Anamas-Akseki autochthonous, and the Beysehir-Hoyran nappes). Emplacement of the nappes during Neotectonic evolution of Eastern Mediterranean region resulted in the formation of the Isparta Angle which has played an important role in tectonic evolution of Turkey and Eastern Mediterranean region. The study area is located in the northeast segment of Antalya Complex and covers an area of approximately 300 km2. Mainly carbonate rock unites constitute the autochthonous basement and overlain tectonicaly by the Obektas formation in olistostromal melange character, Kizildag Peridotite with ophiolitic melange and ophiolite-related metamorphic rocks, Pazarkoy group, and Dulup limestones. Pazarkoy group (Upper Triassic-Lower Cretaceous) include slope, basinal sedimantery rocks formed within passive margin environment, volcanic rocks characterized by different tectonomagmatic environments and serpentinites. Volcanic rocks are observed mainly as massive or pillow lavas at different locations in Pazarkoy group (at Akpinar Tepe, Havutlu, Ayvalipinar). The volcanics outcropping in the vicinity of Akpinar Tepe in alkaline basalt to trachyandesite composition and Ayvalipinar in alkaline basalt composition display nearly OIB-like pattern on the N-MORB normalized spider diagram with slightly negative Nb anomaly reflecting subduction zone affinity. But, on the tectonomagmatic discrimination diagrams (Zr/Y vs. Zr, V vs. Ti/1000), these volcanics plot within WPB field. The volcanics exposed around Havutlu, in Obektas formation and in ophiolitic melange have subalkaline basalt composition and on the primitive-mantle normalized spider diagram they show parallel pattern in HFSE with negative Nb-Ta anomaly. On the Chondrite-normalized REE pattern, volcanics taken from Havutlu display slightly enrichment, taken from Obektas formation display slightly enrichment to slightly depletion, and taken from ophiolitic melange display strongly depletion in LREE. Ophiolitic melange and ophiolite-related metamorphic rocks including amphibolites and calcschists underlie the harzburgitic mantle tectonites (Kizildag peridotite). These peridotites are intruded by isolated diabasic dykes and pyroxenites. On the N-MORB normalized spider diagram, the isolated diabasic dykes are characterized by enrichment in LILE elements (Ba, Rb, Sr, Th), negative Nb-Ta and positive Sr anomaly, and display subduction zone affinity. Based on geological and geochemical findings, it is concluded that Triassic rifting in the northern margin of Gondwana is followed by extension of rift basins from which the sedimentary units of Antalya Complex derived, extrusion of alkaline WPB volcanics (Akpinar Tepe volcanics), subalkaline subduction-related volcanics (Havutlu volcanics, Obektas volcanics, and volcanics in ophiolitic melange). Slope and basinal sedimentary units of Pazarkoy group deposited in passive margin environments during Upper Triassic-Lower Cretaceous. With the initiation of regional compression during upper Cretaceous, SSZ-type Kizildag ophiolites formed in an intraoceanic subduction zone setting and then emplaced on the passive margin deposits. However, timing of formation of the ophiolite-related metamorphic rocks underlying peridotites, before or after the formation of Kizildag ophiolite, is not still known.
DE: 8140 Ophiolites (3042)
DE: 8178 Tectonics and magmatism
SC: Tectonophysics [T]
MN: Fall Meeting 2005