HR: 0800h
AN: T41F-1293    [Abstracts]
TI: Neotectonics and Evolution of the Yenicaga Basin, Bolu - Turkey
AU: * Arca, M
EM: msarca@geo.arizona.edu
AF: University of Arizona, Department of Geosciences 1040 E. 4th Street, Tucson, AZ 85721 United States
AU: * Arca, M
EM: msarca@geo.arizona.edu
AF: Middle East Technical University, Department of Geological Engineering, Ankara, 06531 Turkey
AU: Kocyigit, A
EM: akoc@metu.edu.tr
AF: Middle East Technical University, Department of Geological Engineering, Ankara, 06531 Turkey
AB: The Yenicaga Basin, located along the North Anatolian Fault System, is interpreted to be a fault-wedge basin with the North Anatolian Fault System's master strand, the Gerede Fault, cutting across the basin itself. The basin and its surroundings contain both paleotectonic rock units and neotectonic rock units. Paleotectonic units, which are deposited or formed during prior tectonic regimes, comprise several formations. The most important of these is the Upper Miocene-Lower Pliocene Eskipazar formation which plays an important role in the understanding of the evolutionary history of the basin. The main Neotectonic unit deposited under control of the present tectonic regime is the Plio-Quaternary Betemurlu formation. The Betemurlu formation unconformably overlies the paleotectonic Eskipazar formation throughout the study area and the unconformity separating these two units corresponds to the time interval during which the paleotectonic stress regime changed into the neotectonic stress regime. Thus, the onset age of the strike-slip neotectonic regime in the study area is Late Pliocene (~ 2.6 Ma). Common basin-margin-bounding faults of the Yenicaga Basin are the Asagi Kuldan fault, the Aksu fault, the Izmirli fault set, the Saraycali fault, the Degirmen fault set and the Hamzabey fault set. These fault systems display well-preserved fault scarps in places. Morphological expressions of these faults and their geometrical relationships with the local stress regime indicate that these faults are mainly strike-slip and oblique-slip faults. Morphotectonic expressions of the faults exposed within the study area indicate that these faults remain active. Most of the population centers within the study area are located on water-saturated, loose basin fill near the active faults. Hence, these population centers are open to future earthquake hazards.
DE: 7230 Seismicity and seismotectonics
DE: 8010 Fractures and faults
DE: 8107 Continental neotectonics
DE: 7205 Continental crust (1242)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting