Ordovician arc and syncollisional magmatism in the İstanbul-Zonguldak Tectonic Unit (NW Turkey): Implications for the consumption of the Teisseyre-Tornquist Ocean in Far East Avalonia

Şen, Fatih

doi:10.1007/s00710-023-00812-7

Cited by 5 publications

(5 citation statements)

References 68 publications

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“…They are also intruded by Middle to Late Ordovician granites (c. 464-446 Ma; Okay et al, 2008;Şen, 2023). In the Sünnice mountain, the Yellice metavolcanics include a sequence of low-grade metaandesites with minor metarhyolites and metasedimentary rocks of Middle-Late Ediacaran age, and they are intruded by Middle-Late Ediacaran intrusions (c. 576-556 Ma; Ustaömer et al, 2005;Şen, 2021a).…”

Section: Stratigraphy Of the İstanbul-zonguldak Tectonic Unitmentioning

confidence: 99%

Defining the soft-docking of Avalonia and Baltica and the Caledonian Orogeny in the İstanbul-Zonguldak Tectonic Unit (NW Turkey): Geochronological and geochemically data from the Silurian gabbro apophyses and dykes in the İstanbul Terrane

Şen

2023

Preprint

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The İstanbul-Zonguldak Tectonic Unit (NW Turkey) is the unmetamorphosed continental fragment of Far East Avalonia. It contains sedimentary rocks, ranging in age from Upper Ediacaran to Carboniferous, consisting of the İstanbul and Zonguldak Terranes. It is characterized by a sequence with stratigraphic gaps in two different times, including the Ediacaran–Cambrian and Silurian–Devonian transition. On the other hand, unconformity planes are observed in the Silurian-Devonian transition in the Zonguldak Terrane, while defining as a conformable transition in the İstanbul Terrane in spite of lacking strata of the Silurian-Devonian transition. Here, I present analytical data of gabbro apophyses and dykes in the İstanbul Terrane. They have porphyritic and ophitic textures. U-Pb dating on igneous zircons from gabbro apophyses yields Early Silurian of ca. 434.2 ± 1.1 Ma (2σ) and its Pb-loss ages define the Early Devonian of ca. 415.5 ± 2.1 Ma (2σ), ranging in age from 420 to 410 Ma. Geochemically, gabbro apophyses and dykes show alkaline character, and include with-in plate components; however, they are magmatic products of a syncollisional setting. Overall, I suggest that Early Silurian gabbro intrusions intruded into the İstanbul Terrane during the last phase of soft-docking event, formed at 443-425 Ma between Far East Avalonia and Baltica. Additionally, Early Devonian Pb-loss ages of gabbro intrusive rocks in the İstanbul Terrane correspond to unconformity planes in the Zonguldak Terrane, thus indicating the deformational effect of the Caledonian orogeny in the İstanbul Terrane. All in all, these data display that the absence of sedimentary rocks in the Silurian-Devonian transition in the İstanbul Terrane relates to the existence of a stratigraphic gap during this time.

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Section: Stratigraphy Of the İstanbul-zonguldak Tectonic Unitmentioning

confidence: 99%

Defining the soft-docking of Avalonia and Baltica and the Caledonian Orogeny in the İstanbul-Zonguldak Tectonic Unit (NW Turkey): Geochronological and geochemically data from the Silurian gabbro apophyses and dykes in the İstanbul Terrane

Şen

2023

Preprint

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“…They are cut by Early Cambrian to Late Ordovician intrusive rocks (c. 517-511 Ma; Bozkurt et al, 2013;c. 484-443 Ma;Şen 2023a). In the Karadere area, the basement rocks are represented by the Doruk-Yayla metamorphics, consisting of meta-quartzites and gneisses of Tonian-Cryogenian age and the Avalonian intrusive granitic rocks cutting them (c. 590-568 Ma; Chen et al, 2002) (Figure 3).…”

Section: Stratigraphy Of the İstanbul-zonguldak Tectonic Unit (İztu)mentioning

confidence: 99%

“…The sedimentation of the lagoonal-fills, known as the Gözdağ-Dolayoba Formations, is Middle Ordovician-Late Silurian (Dean et al, 2000;Özgül, 2012;Sayar and Cocks, 2013). The rift-and -siliciclastic platform fills are cut by Late Ordovician intrusive rocks (c. 444-443 Ma;Şen, 2023), corresponding to felsic lavas in the Ordovician-Silurian transition in the İT (Figure 3). The Upper Silurian-Lower Devonian fills begin with laminated limestone-shale and pass upward into nodular limestones, known as the İstinye Formation (Önalan, 1981).…”

Section: Stratigraphy Of the İstanbul-zonguldak Tectonic Unit (İztu)mentioning

confidence: 99%

“…The continental margin successions of the Rheic Ocean were deposited on the north side and arc magmatism occurred on the south side from the Middle Ediacaran to the Late Cambrian (c. 590-500 Ma; Şen, 2021a). In the southern part of the İZTU, the Teisseyre-Tornquist Ocean, the east branch of Iapetus, continued to subduct under the Far East Avalonian terranes during the Early to Late Ordovician (c. 490-445 Ma;Şen, 2023a). The Middle-Late Ordovician arc magmatism in the Armutlu peninsula of the İT (c. 464-446 Ma;Okay et al, 2008Okay et al, after Şen, 2023a and the Early Ordovician arc magmatism in the Sünnice mountain of the ZT (c. 484 Ma;Şen, 2023a) represent Ordovician arc-related magmatism that took place during the consumption of the Teisseyre-Tornquist Ocean.…”

Section: Geodynamic Implications Of the Late Ordovician Volcanic Rock...mentioning

confidence: 99%

“…In the southern part of the İZTU, the Teisseyre-Tornquist Ocean, the east branch of Iapetus, continued to subduct under the Far East Avalonian terranes during the Early to Late Ordovician (c. 490-445 Ma;Şen, 2023a). The Middle-Late Ordovician arc magmatism in the Armutlu peninsula of the İT (c. 464-446 Ma;Okay et al, 2008Okay et al, after Şen, 2023a and the Early Ordovician arc magmatism in the Sünnice mountain of the ZT (c. 484 Ma;Şen, 2023a) represent Ordovician arc-related magmatism that took place during the consumption of the Teisseyre-Tornquist Ocean. Besides, the chondrite-normalized REE pattern of the Katian coarse-grained tuffs (T 2 ) is represented by LREE enrichment (Ce N /Yb N = 2.53-3.26) (Table 2).…”

Section: Geodynamic Implications Of the Late Ordovician Volcanic Rock...mentioning

confidence: 99%

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Geological and geochemical characteristics of Late Ordovician volcanic levels of the Gözdağ Formation in the İstanbul-Zonguldak Tectonic Unit (NW Turkey): Implications for global events during the Ordovician

Şen

2023

Türkiye Jeol. Bül.

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The İstanbul-Zonguldak Tectonic Unit is regarded as the easternmost fragment of Avalonia-Carolina and stands for Far East Avalonia. Its stratigraphy also is characterized by discontinuous sedimentation from Late Ediacaran to Late Carboniferous. In the western part of the block, known as the İstanbul Terrane, the Gözdağ Formation is represented by lagoonal sedimentary rocks consisting of shale-sandstone with limestone of Middle Ordovician-Lower Silurian age. Here, I report on stratigraphic positions and petrographical and geochemical data of fine- and coarse-grained tuffs and lavas in the Late Ordovician strata of the Gözdağ Formation. The fine- and coarse-grained tuffs have pyroclastic and the lavas have porphyritic, vitrophyric and aphanitic textures. The fine-and coarse-grained tuffs are Sandbian and Katian ages, and the lavas are Hirnantian ages, according to the stratigraphic positions of the Late Ordovician volcanic rocks. Geochemically, the-fine grained tuffs have High-K calc-alkaline character and the coarse-grained tuffs and lavas have calc-alkaline affinity. They are devoid of noticeable with-in plate components, as deduced by the presence of obvious negative Nb anomalies, and they have subduction signatures. In conjunction with the data from literature, the Sandbian fine-grained tuffs were deposited in a lagoonal depocenter in the İstanbul-Zonguldak Tectonic Unit during the Taconic orogeny formed in the earliest late Ordovician between the Piedmont Terrane and Laurentia. The Katian coarse-grained tuffs were deposited in a shallow marine in it during the last phase of the consumption of the Teisseyre-Tornquist Ocean from volcanoes occurred in volcanic arc-related settings. Besides, I the Hirnantian lavas flowed in a lagoonal depocenter in it during the soft-docking of Avalonia and Baltica, known as the pre-Caledonian orogeny.

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Revisiting the depositional age and provenance characteristics of metasedimentary rocks from the basement units in the Central Pontides (N Turkey): New constraints for tectonic evolution of the southern Black Sea region

Çimen,

Ali Gücer,

Akal

et al. 2024

Journal of Asian Earth Sciences

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Ordovician arc and syncollisional magmatism in the İstanbul-Zonguldak Tectonic Unit (NW Turkey): Implications for the consumption of the Teisseyre-Tornquist Ocean in Far East Avalonia

Cited by 5 publications

References 68 publications

Defining the soft-docking of Avalonia and Baltica and the Caledonian Orogeny in the İstanbul-Zonguldak Tectonic Unit (NW Turkey): Geochronological and geochemically data from the Silurian gabbro apophyses and dykes in the İstanbul Terrane

Defining the soft-docking of Avalonia and Baltica and the Caledonian Orogeny in the İstanbul-Zonguldak Tectonic Unit (NW Turkey): Geochronological and geochemically data from the Silurian gabbro apophyses and dykes in the İstanbul Terrane

Geological and geochemical characteristics of Late Ordovician volcanic levels of the Gözdağ Formation in the İstanbul-Zonguldak Tectonic Unit (NW Turkey): Implications for global events during the Ordovician

Revisiting the depositional age and provenance characteristics of metasedimentary rocks from the basement units in the Central Pontides (N Turkey): New constraints for tectonic evolution of the southern Black Sea region

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