Semih Can Ülgen

In many ancient and active volcanic provinces, dyke systems are commonly disposed radially and concentrically around the volcanic chimney, represented by a central intrusive body in many eroded examples. In Istanbul, NW Turkey, late Cretaceous dykes, which are emplaced into the pre-Cretaceous basement consisting of sedimentary rocks of Palaeozoic a...

Spatially continuous rock assemblages that share similar environmental evolution or structural features can be classified as a single tectonic unit. This approach enables to link dispersed units or massifs with each other and sometimes can be subjective, depending on the classification criteria. The relationship and the nature of the contact betwee...

The Istanbul region is a part of a bigger continental fragment called the Rhodope-Pontide Fragment. Within this continental fragment, the Istanbul Zone consists, at the base, of a Neoproterozoic middle to high-grade crystalline rocks with relicts of volcanic arc and continental crust, which are not observed in Istanbul itself, but farther east near...

The city of İstanbul lies at the boundary between Europe and Asia in NW Turkey. Beside the city’s unique geographical position its geology is also unique. İstanbul sits on an isolated and well developed, continuous Palaeozoic sequence. The Palaeozoic sequence is unmetamorphosed despite the fact that it was affected by three orogenies; Hercynian, Ci...

Valles Marineris remains one of the most intriguing morphological features on Mars. Notwithstanding the near-consensus that it is a rift structure , created by a large-scale extensional stress field, there are serious shortcomings to this claim. The most obvious of these is that this valley system does not look even remotely like any rift structure...

Valles Marineris is the most significant near-linear depression on Mars. It is some 4000 km long, up to about 200 km wide and some 7 km deep. Although its margins look parallel at first sight, the entire structure has a long spindle shape with significant enlargement in its middle (Melas Chasma) caused by cuspate slope retreat mechanisms. Farther t...

Istanbul which is one of the most populous and areally most extensive cities of the World, lies athwart the boundary between Europe and Asia in NW Turkey and sits on an isolated Palaeozoic transgressive passive margin sequence. This sequence is inferred to lie on a latest Precambrian basement and shows no evidence of metamorphism despite the fact t...

The Permian extinction was not universal as at least some sections in Japan, New Zealand and the US Cordillera show continuous faunal records and no anoxia. By contrast, evidence for Capitanian and Changsingian extinctions in and around the Palaeo-Tethys is ubiquitous. This has led to the suggestion that the major Permian extinctions were confined...

This paper is an exercise in “public thinking”, because we are not yet commited to what it concludes, on account of our ignorance of the Mauritenide evolution in terms of our present conclusion. The only excuse for presenting it here is the invitation to do so by Chris Scotese. We then hope that the audience might help us straighten out our thinkin...

The study of a Ypresian flysch sequence, immediately southern of the Intra-Pontid suture zone and overlying the Upper Cretaceous basement rocks, permit us to comment on the late Cretaceous-early Tertiary tectonic history of the region This flysch sequence with a thickness 1500-2000 m consisting of sandstones, shales and conglomerates derived from t...

An ophiolitic mélange and associated metamorphic rocks crop out south of the Sea of Marmara in the Mudanya-Zeytinbağı region. The oldest rocks in the area stuided are low-grade greenschist facies metamorphics sequence consisting of metabasite, phyllite, metachert and marble. They are tectonically juxtaposed with serpentinite slices and an ophioliti...

An ophiolitic mélange and associated metamorphic rocks crop out south of the Sea of Marmara in the Mudanya-Zeytinbağı region. The oldest rocks in the area studied are low-grade greenschist facies metamorphic sequence consisting of metabasite, phyllite, metachert and marble. They are tectonically juxtaposed with serpentinite slices and an ophiolitic...

This study is prepared due to field surveys in summers of 2009 and 2010 in Bursa-Zeytinbağı region. Studied area is bounded with Marmara Sea in the North, Beşarmutlar faulta and Neogen sediments in the South. Upper Crateceous Trilye Complex, Upper Paleocene Maili Limestone, Lower Eocene aged Zeytinbağı Formation which is consisted of flysch, Middle...

An ophiolitic mélange and associated metamorphic rocks crop out south of the Sea of Marmara in the Mudanya-Zeytinbagı region. The oldest rocks in the area studied are low-grade greenschist facies metamorphics sequence consisting of metabasite, phyllite, metachert and marble. They are tectonically juxtaposed with serpentinite slices and an ophioliti...

In this study northeastern Gökçeada’s Eocene-Oligocen eaged sedimentologic and tectonic evolution history is tried to define. In this sense geological map of study area and thin sections are prepared. Study area is limited by Kaleköy in North, Gökçeada towncenter in south and with kuzulimanı in east. Deposits in study area was formed while opening...