27 research outputs found
The 2005 - 2007 Bala (Ankara, central Turkey) earthquakes: a case study for strike-slip fault terminations
An intense seismic activity has been observed after the Bala (Ankara, NW central Turkey) earthquakes (30 July 2005: Mw=5.3, 20 December 2007: Mw=5.4, and 26 December 2007: Mw=5.3), continuing up to the present. The epicenters and the focal mechanism solutions of the earthquakes indicate that the right lateral strike-slip Afşar fault, trending N55-60°W, is responsible for the main shocks. The Afşar fault is thought to be the NW continuation of the Tuzgölü fault zone, which is one of the main neotectonic elements in central Anatolia. On the other hand, the aftershock distributions of the 2005 event have a NNE trend, and those of the 2007 event show a NW trending. Some focal mechanism solutions of the 2005 Bala earthquake aftershocks indicate normal and oblique normal faulting that corresponds to the NNE-trending Karakeçili fault. It seems that seismic activation of the NNE-trending Karakeçili fault was triggered by the 2005 main shock (Mw=5.3) that occurred on the NW trending right lateral strike-slip Afşar fault. The overall neotectonic framework is that the northwestern edge of the Tuzgölü fault zone, represented by the Afşar fault in Bala, terminates in an extensional system represented by the oblique-slip Karakeçili fault
High-K volcanism in the Afyon region, western Turkey: from Si-oversaturated to Si-undersaturated volcanism
Volcanic rocks of the Afyon province (eastern
part of western Anatolia) make up a multistage potassic and ultrapotassic alkaline series dated from 14 to 12 Ma. The early-stage Si-oversaturated volcanic rocks around the Afyon city and further southward are trachyandesitic volcanic activity (14.23 ± 0.09 Ma). Late-stage Si-undersaturated volcanism in the southernmost part of the Afyon volcanic province took place in three episodes inferred from their stratigraphic relationships and ages. Melilite–
leucitites (11.50 ± 0.03 Ma), spotted rachyandesites, tephryphonolites and lamproites (11.91 ± 0.13 Ma) formed in the first episode; trachyandesites in the second episode and finally phonotephrites, phonolite, basaltic trachyandesites and nosean-bearing trachyandesites during the last episode.
The parameter Q [normative q-(ne + lc + kls + ol)] of western Anatolia volcanism clearly decreased southward with time becoming zero in the time interval 10–15 Ma.
The magmatism experienced a sudden change in the extent of Si saturation after 14 Ma, during late-stage volcanic activity of Afyon volcanic province at around 12 Ma, though there was some coexistence of Si-oversaturated and Si-undersaturated magmas during the whole life of Afyon volcanic province
Reconciling the stratigraphy and depositional history of the Lycian orogen-top basins, SW Anatolia
Terrestrial fossil records from the SWAnatolian basins are crucial both for regional correlations and palaeoenvironmental reconstructions.
By reassessing biostratigraphic constraints and incorporating new fossil data, we calibrated and reconstructed the late Neogene
andQuaternary palaeoenvironments within a regional palaeogeographical framework. The culmination of the Taurides inSWAnatolia
was followed by a regional crustal extension from the late Tortonian onwards that created a broad array of NE-trending orogen-top
basins with synchronic associations of alluvial fan, fluvial and lacustrine deposits. The terrestrial basins are superimposed on the upper
Burdigalian marine units with a c. 7 myr of hiatus that corresponds to a shift from regional shortening to extension. The initial infill of
these basins is documented by a transition from marginal alluvial fans and axial fluvial systems into central shallow-perennial lakes
coinciding with a climatic shift from warm/humid to arid conditions. The basal alluvial fan deposits abound in fossil macro-mammals
of an early Turolian (MN11–12; late Tortonian) age. The Pliocene epoch in the region was punctuated by subhumid/humid conditions
resulting in a rise of local base levels and expansion of lakes as evidenced by marsh-swamp deposits containing diverse fossilmammal
assemblages indicating late Ruscinian (lateMN15; late Zanclean) ageWe are grateful for the support of the international
bilateral project between The Scientific and Technological Research
Council of Turkey (TUBITAK) and The Russian Scientific Foundation
(RFBR) with grant a number of 111Y192. M.C.A. is grateful to the
Turkish Academy of Sciences (TUBA) for a GEBIP (Young Scientist
Award) grant. T.K. and S.M. are grateful to the Ege University
Scientific Research Center for the TTM/002/2016 and TTM/001/2016
projects. M.C.A., H.A., S.M. and M.B. have obtained Martin and
Temmick Fellowships at Naturalis Biodiversity Center (Leiden). F.A.D.
is supported by a Mehmet Akif Ersoy University Scientific Research
Grant. T.A.N. is supported by an Alexander-von-Humboldt
Scholarship. L.H.O. received support from TUBITAK under the 2221
program for visiting scientists