International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
bodies and carbonate rocks in the western-southwestern part
of the study area.
Figure 3. The main active faults of the study area were
represented on the LANDSAT-TM (541) image mosaic.
The length & width and age of the active grabens in the MM
increase gradually from the Kütahya Graben in the NNE to
the Büyük Menderes Graben in the SSW direction, just at the
south of the study area. The trends of graben and also the
types of the faults of the recent tectonics show changes in the
WSW part of the study area. This area is the adjacent to the
NAFS and locates between two massifs, Kazdag and
Menderes. It can be concluded that the area has been moving
towards the SW direction between these massifs during the
neotectonic period according to the general arrangement of the
faults and the visual interpretation of the overall structure of
the region. The complex rock structure of the basement as
mentioned above and also the NE-trend paleotectonic
arrangement are forming a similar spoon-shaped structure in
this area. This movement can be ascribed on a sub-horizontal
detachment fault surface like a landslide movement. Akman
and Sari (2002) proposed also a similar model. It is observed
in many locations that there are the NE- and NW-trending
oblique-slip normal faults frequently. Also, the NW-and
WNW-trending normal faults, and some ENE-trending strike-
slips on faults were observed. Nebert (1978) also determined
several strike-slips on the faults in Soma coal basin.
The neotectonic stage including recent active fault development
in Turkey was begun in the Pliocene time (Kogyigit et al. 1999,
2000, Koçyigit and Ozacar, 2003). They proposed that
Anatolian plate began to escape towards west-southwest
direction after the sea-floor spreading of Red Sea (based on
Hempton's data in 1987) in Early Pliocene time. Therefore, the
neotectonic period of west Anatolia initiated around 3 million
years ago.
The Neogene sedimentation in western Anatolia began in Early
Miocene trending in the NE direction basins that include mostly
coal beds. The graben bounding faults can be traced partly in
the satellite images and also verified some of them by the
ground-truth studies. However, it is not so clear that if those
faults are the baundary faults of the coal basins in the Early
Miocene time. The previous coal investigations (MTA reports)
give in Early-Middle Miocene age to the first coal beds
according to sporomorphs. But Nebert (1978) accepts the first
coal sedimentation in Late Miocene age and suggests that there
are three sedimentation stages in the Soma area, which can be
distinguished by erosion levels; (1) Soma Formation deposited
in the Late Miocene time, (2) Denis Formation deposited in the
Lower Pliocene time, and (3) the sediments deposited during
Quaternary. However, the lower coal beds are assigned to Early
Miocene according to the macro- and micromammalian fossils
(Saraç, 2003). It is accepted that there are two main extensional
periods at least in western Anatolia. It was observed (by the
ground truth studies and also Kogyigit et al. 1999, 2000;
Kocyigit and Ozacar 2003) that the lower series rather folded
and deformed. The basins that have been developed in the
WNW-ESE trend (Figure 5 a, b) and include volcanic rocks and
sedimentary deposits around Soma, Balikesir and Kiitahya
corresponding to Denis Formation of Nebert (1978). The
volcanic rocks around the western parts of the area in the Figure
5 are dated Middle Miocene ages according to radiometric
determinations (Ercan et al. 1997).
Figure 4. The
distribution of
grabens in the
study area. The
main active faults
on the basemap
that is the painted
relief map.
KMG: Küçük
Menderes
Graben,
DG: Dinar
Graben,
AG: Akçay
Graben,
BG: Bakirçay
Graben, MAG:
Manisa-Akhisar
Graben, Bg:
Bigadic Graben,
BIG: Bozóyük-
inegol Graben,
BB: Balikesir
Basin.
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