Important new ichnological data was obtained from the Isparta Çay Formation (Triassic to early Cretaceous), Koçtepe Formation (middle Paleocene to Early Eocene), Isparta Formation (Early to Middle Eocene) and İncesu Formation (Middle Eocene to Early Oligocene). These formations are significantly exposed in the Eğirdir, Gönen and Isparta regions within the northern part of the Isparta Angle. An overview of the stratigraphy and its trace-fossil bearing formations and microfossil content is presented together with recommendations. The density and diversity of trace fossils vary between and within these formations, which originated in deep-marine shelf slope and shelf environments of the Neotethys ocean. Changes in the frequency of abrupt turbiditic deposition, oxygenation of the bottom water and possibly food availability are reflective in the trace fossil distribution. The trace fossils of the Isparta Çay, Koçtepe and Isparta formations are typical of deep-marine settings with occasional high-energy turbiditic conditions. The Isparta Çay Formation (Paleodictyon ichnosubfacies) is seen as the bedrocks of the region, whereas the Isparta Formation (Ophiomorpha rudis ichnosubfacies) overlies conformably the Koçtepe Formation (Nereites and Arenicolites ichnofacies). The İncesu Formation is laterally interlaced with the Isparta Formation. A high diversity of trace fossils occurs in the İncesu Formation (Zoophycos ichnofacies), which was formed in an outer shelf environment. Findings from previous ichnological investigations in Turkey are compiled and compared with the present results from the Isparta Angle

S U M M A R YDetermination of the fault geometry in the Marmara Sea has been a major problem for the researchers after the occurrence of the 1999 August 17 Golcuk (M = 7.4) earthquake. To shed a light to the problem we applied the pre-stack Kirchhoff depth migration technique to the multichannel seismic reflection data of three profiles to investigate the basin and fault geometry in the Tekirdag Basin in the western Marmara Sea. The boundary of the basin and its sediments were revealed in N-S and NE-SW directions in depth sections. We identify major fault types involving these structures at different locations in Tekirdag Basin showing that the basin is developed under their movement. The North Anatolian Fault is imaged and interpreted as transtensional character at the centre of the Tekirdag Basin that is symmetrically divided with a large distributed zone. The fault plane is imaged through the depth of 2 km dipping to the north with 90 • in the upper 350 m and 82 • in the lower part. The basin thickness reaches about 2.5 km at that point. Syn-transform sediments of the basin are disturbed by some normal faults dipping to the north. These faults are represented by notable displacements of the reflections which prompted us to consider them as a potential tsunami source if they move during a large earthquake along the major fault. Another major fault is identified at the westernmost of the basin. Because it shows the same character as Ganos fault, it might be submarine part of it. It has reverse component with the dip angle of 65 • to the north and trending along the western flank of the basin. A reverse fault is identified appearing in low angle (∼20 • ) surrounding the edge of the submarine slide at southwest of the basin. From its geometry it is interpreted as a local fault formed between two main faults. From the sketch of the basin and the fault geometry obtained from the images we suggest that the basin should be formed by a pull-apart system.

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