Abstract Numerous Oligo-Miocene plutonic and associated aplite-pegmatite rocks occur in the Weste... more Abstract Numerous Oligo-Miocene plutonic and associated aplite-pegmatite rocks occur in the Western Anatolian Magmatic Complex. However, only the plutons of Namazgah, Karadag, Sogucak and Karadoru, in the Biga Peninsula, host three different types of tourmaline: disseminated, nodular, and vein-type. These all fall into the alkali subgroup and schorl-oxy-schorl-dravite-oxy-dravite solid solution series. This study shows they were formed during late magmatic to hydrothermal stages in the roof sections (at shallow crustal levels) of the granitoid intrusions. Tourmaline compositions remained fairly homogeneous during the formation and evolution of each stage.
In NE Türkiye, an almost 30,000 km2 area is covered by young volcanic rocks, ranging in age from ... more In NE Türkiye, an almost 30,000 km2 area is covered by young volcanic rocks, ranging in age from Miocene to Quaternary and spanning the whole compositional spectrum from basanites/tephrites to high silica rhyolites. The region exhibits a plateau morphology, known as the Erzurum-Kars Plateau, at ~2 km above sea level. That volcanic plateau continues far beyond the state border into Georgia (ie., the Samtskhe-Javakheti plateaus). Although there are a few studies, the petrological evolution of the these volcanic plateaus is still not well known. To better understand the origin, magmatic history, and geodynamic setting of the volcanism on these plateaus, we, Turkish and Georgian researchers, have been conducting a joint cross-border research project (i.e., TÜBİTAK- SRGNSF project #118Y272) across the region. The volcanic units making up those plateaus are composed of numerous volcanic cones of different shapes and sizes, lava domes, pyroclastic layers, and widespread plateau-forming la...
The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour a... more The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour at İstanbul contains the records of sea level, environmental changes and the cultural history of the region. The cobbles at the base of the sequence include archaeological remnants of Neolithic culture that settled in the area between 8.4 and 7.3 14C ka BP, and are located at 6 m below the present sea level. The sediments representing a coastal environment indicate that the area was used as a harbour from AD 4th to at least the 11th century and were filled by the sediments derived from Lykos Stream after 11th century.
The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour a... more The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour at İstanbul contains the records of sea level, environmental changes and the cultural history of the region. The cobbles at the base of the sequence include archaeological remnants of Neolithic culture that settled in the area between 8.4 and 7.3 14C ka BP, and are located at 6 m below the present sea level. The sediments representing a coastal environment indicate that the area was used as a harbour from AD 4th to at least the 11th century and were filled by the sediments derived from Lykos Stream after 11th century.
An extensive rescue excavation has been conducted in the ancient harbor of İstanbul (Yenikapı) by... more An extensive rescue excavation has been conducted in the ancient harbor of İstanbul (Yenikapı) by the Sea of Marmara, revealing a depositional sequence displaying clear evidence of transgression and coastal progradation during the Holocene. The basal layer of this sequence lies at 6 m below the present sea level and contains remains of a Neolithic settlement known to have been present in the area, indicating that the sea level at ~ 8–9 cal ka BP was lower than 6 m below present. Sea level advanced to its maximum at ~ 6.8–7 cal ka BP, drowning Lykos Stream and forming an inlet at its mouth. After ~ 3 cal ka BP, coastal progradation became evident. Subsequent construction of the Byzantine Harbor (Theodosius; 4th century AD) created a restricted small basin and accumulation of fine-grained sediments. The sedimentation rate was increased due to coastal progradation and anthropogenic factors during the deposition of coarse-grained sediments at the upper parts of the sequence (7th–9th cen...
Devonian in Turkey — a reviewThe Devonian Period is represented in Turkey by almost complete non-... more Devonian in Turkey — a reviewThe Devonian Period is represented in Turkey by almost complete non-metamorphic sections of more than 1000 meters, which exhibit varying lithofacial associations. They are parts of thick Paleozoic sedimentary successions in the Pontides, Taurides and Arabian Plate. The tectonic setting and the paleogeographical origin of these terranes is different. Therefore, the litho- and biostratigraphy and facies characteristics of these Devonian successions would enable a comparison and a paleogeographical assignment of these tectono-stratigraphic units. Devonian successions of the Arabian Plate and of the Taurides are represented by facies associations ranging from tidal flat to a deep shelf. Whereas, those of the Istanbul and Çamdağ-Zonguldak areas in the Pontides by a deepening upward sequence from a shallow shelf into a basin and a stable shelf, respectively. The Devonian of the Arabian Plate and the Taurides can surely be assigned to Gondwana. A Peri-Gondwanan...
Abstract Numerous Oligo-Miocene plutonic and associated aplite-pegmatite rocks occur in the Weste... more Abstract Numerous Oligo-Miocene plutonic and associated aplite-pegmatite rocks occur in the Western Anatolian Magmatic Complex. However, only the plutons of Namazgah, Karadag, Sogucak and Karadoru, in the Biga Peninsula, host three different types of tourmaline: disseminated, nodular, and vein-type. These all fall into the alkali subgroup and schorl-oxy-schorl-dravite-oxy-dravite solid solution series. This study shows they were formed during late magmatic to hydrothermal stages in the roof sections (at shallow crustal levels) of the granitoid intrusions. Tourmaline compositions remained fairly homogeneous during the formation and evolution of each stage.
In NE Türkiye, an almost 30,000 km2 area is covered by young volcanic rocks, ranging in age from ... more In NE Türkiye, an almost 30,000 km2 area is covered by young volcanic rocks, ranging in age from Miocene to Quaternary and spanning the whole compositional spectrum from basanites/tephrites to high silica rhyolites. The region exhibits a plateau morphology, known as the Erzurum-Kars Plateau, at ~2 km above sea level. That volcanic plateau continues far beyond the state border into Georgia (ie., the Samtskhe-Javakheti plateaus). Although there are a few studies, the petrological evolution of the these volcanic plateaus is still not well known. To better understand the origin, magmatic history, and geodynamic setting of the volcanism on these plateaus, we, Turkish and Georgian researchers, have been conducting a joint cross-border research project (i.e., TÜBİTAK- SRGNSF project #118Y272) across the region. The volcanic units making up those plateaus are composed of numerous volcanic cones of different shapes and sizes, lava domes, pyroclastic layers, and widespread plateau-forming la...
The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour a... more The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour at İstanbul contains the records of sea level, environmental changes and the cultural history of the region. The cobbles at the base of the sequence include archaeological remnants of Neolithic culture that settled in the area between 8.4 and 7.3 14C ka BP, and are located at 6 m below the present sea level. The sediments representing a coastal environment indicate that the area was used as a harbour from AD 4th to at least the 11th century and were filled by the sediments derived from Lykos Stream after 11th century.
The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour a... more The sedimentary sequence discovered at archaeological excavations in ancient Theodosius Harbour at İstanbul contains the records of sea level, environmental changes and the cultural history of the region. The cobbles at the base of the sequence include archaeological remnants of Neolithic culture that settled in the area between 8.4 and 7.3 14C ka BP, and are located at 6 m below the present sea level. The sediments representing a coastal environment indicate that the area was used as a harbour from AD 4th to at least the 11th century and were filled by the sediments derived from Lykos Stream after 11th century.
An extensive rescue excavation has been conducted in the ancient harbor of İstanbul (Yenikapı) by... more An extensive rescue excavation has been conducted in the ancient harbor of İstanbul (Yenikapı) by the Sea of Marmara, revealing a depositional sequence displaying clear evidence of transgression and coastal progradation during the Holocene. The basal layer of this sequence lies at 6 m below the present sea level and contains remains of a Neolithic settlement known to have been present in the area, indicating that the sea level at ~ 8–9 cal ka BP was lower than 6 m below present. Sea level advanced to its maximum at ~ 6.8–7 cal ka BP, drowning Lykos Stream and forming an inlet at its mouth. After ~ 3 cal ka BP, coastal progradation became evident. Subsequent construction of the Byzantine Harbor (Theodosius; 4th century AD) created a restricted small basin and accumulation of fine-grained sediments. The sedimentation rate was increased due to coastal progradation and anthropogenic factors during the deposition of coarse-grained sediments at the upper parts of the sequence (7th–9th cen...
Devonian in Turkey — a reviewThe Devonian Period is represented in Turkey by almost complete non-... more Devonian in Turkey — a reviewThe Devonian Period is represented in Turkey by almost complete non-metamorphic sections of more than 1000 meters, which exhibit varying lithofacial associations. They are parts of thick Paleozoic sedimentary successions in the Pontides, Taurides and Arabian Plate. The tectonic setting and the paleogeographical origin of these terranes is different. Therefore, the litho- and biostratigraphy and facies characteristics of these Devonian successions would enable a comparison and a paleogeographical assignment of these tectono-stratigraphic units. Devonian successions of the Arabian Plate and of the Taurides are represented by facies associations ranging from tidal flat to a deep shelf. Whereas, those of the Istanbul and Çamdağ-Zonguldak areas in the Pontides by a deepening upward sequence from a shallow shelf into a basin and a stable shelf, respectively. The Devonian of the Arabian Plate and the Taurides can surely be assigned to Gondwana. A Peri-Gondwanan...
Uploads
Papers by Isak yılmaz