Beyşehir-Hoyran Napları, Jura-Erken Kretase Yaşlı Boyalıtepe İstifi’nin Radyolarya Biyokronolojisi (Karaman İli Batısı, Konya İli Güneyi, Orta Toroslar)
Özet
The Tauride-Anatolide Platform, in which the Taurus Mountains are located, represents a micro-continent located between the Northern and Southern Branches of the Neotethys Ocean. There are three main nap packs (Bolkardağı, Hadim and Beyşehir-Hoyran) derived from the northern branch of the Neotethys Ocean on this platform. Beyşehir-Hoyran nappes of these three nappe packs are mostly composed of Boyalıtepe, Huğlu, Gencek and Ophiolite units. Among these units, the Boyalıtepe sequence includes Late Triassic-Early Jurassic platform limestones and late Early Jurassic-Late Cretaceous pelagic successions overlying these units.
Considering its current geological position, it is seen that the Beysehir-Hoyran Nappes widely exposed in the west of Karaman Province and in the south of Konya Province. Although the characteristics of the Boyalıtepe sequence have been studied in detail in its type locality (Beyşehir District), it has not been studied sufficiently in the study area located in the west of Karaman Province and south of Konya Province.
Within the scope of field studies of this thesis, samples were collected along Stratigraphic Sections (Oyuklu, Kömürlük and Saliyayla) from the blocks belonging to the Boyalıtepe sequence in the sedimentary mélange. Samples of pelagic sediments (Radiolarian cherts and limestones) collected in field studies were washed in the laboratory and the Radiolarian assemblages they contained were identified.
The Oyuklu Stratigraphic Section, which was examined within the scope of this thesis study, was measured 3 km south to İhsaniye District of Karaman Province. At the lowermost levels of the 134.5-meters-long section, Late Triassic gray-white colored, thin-bedded, chert encrusted limestones are found. After the approximately 32.5 m, there is a thin clay layer representing the Triassic-Jurassic boundary. Following the Triassic-Jurassic boundary clay, limestones with pink colored chert bands and nodules observed along the central part of the section. There are black chert layers in the upper part of the section. Following the black cherts, pink-red colored chert-mudstone alternation observed. The Radiolarian assemblage, consisting of 16 genus and 31 taxa, corresponding to the Early-Middle Jurassic (Bajocian) age range, was identified from the samples collected from the chert-mudstone alternation in the upper part of the section. In addition, one new species belonging to the genus Zartus was identified within the Radiolarian fauna obtained from the samples of the Oyuklu Stratigraphic Section.
Saliyayla Stratigraphic Section was measured around Ahaliçeşme locality, which is located at approximately 6 km northwest to Balcılar District of Konya Province. At the lowermost levels of the section with a total length of 185 meters, there are gray-cream colored chert encrusted and nodular limestones. Towards the lower-middle levels of the section, there are pink colored limestones with abundant chert nodules. The middle-upper levels of the section consist of chert-mudstone alternation. In the uppermost levels, there are cherty limestones and thin medium bedded chert layers. Two different Radiolarian assemblages consisting of 31 taxa belonging to a total of 21 genus corresponding to the Late Jurassic (late Kimmeridgian-early Tithonian) and Early Cretaceous (Berriasian-Valanghinian) interval were identified from the samples collected from the cherts in the middle-upper part of the Saliyayla Stratigraphic Section.
Kömürlük Stratigraphic Section, with a total length of 15 meters, was measured at approximately 10 km southwest of Bozkandak District of Karaman Province. The whole section consists of chert-mudstone alternation. Radiolarian taxa were identified in all of the samples collected from Kömürlük Stratigraphic Section. In the Kömürlük Stratigraphic Section, Radiolarian assemblages consisting of 45 taxa belonging to a total of 32 genus corresponding to the Middle Jurassic (Bajocian-Callovian) interval were identified.
Within the scope of this study, it was understood that detrital limestones were deposited under platform conditions during the Late Triassic - Early Jurassic period, depending on the data obtained from the Oyuklu and Saliyayla Stratigraphic Sections. The data obtained from the Oyuklu, Salıyayla and Kömürlük Stratigraphic Sections have shown that a sudden deepening developed during the Middle-Late Jurassic period and as a result of this deepening, radiolarian pelagic successions developed in large areas. In addition, due to the presence of Early Cretaceous pelagic limestones overlying the Late Jurassic chert-mudstone alternation in the Saliyayla Stratigraphic Section, it was understood that the succession started to become shallow from the Cretaceous.
