Volume 1 , Issue 1 , January 2016 , Pages 1-26
Abdulla Amir Omar 1 ; Rebar Tahssen Ali 1
1 University of Salahaddin-College of Science- Department of Geology- Iraq-Kurdistan region-Arbil
Geoinformatic techniques applied for tectonic lineament extraction and analysis in
Tawke Oil field, Kurdistan region of Iraq. Two satellite images have been used, which
were Landsat ETM+ and ASTER images to extract lineaments both visually and
automatically. It comprises several steps, which involve several enhancing techniques
e.g. Color Composite, Spectral Rationing and Principle Component Analysis. From
combination of all techniques, the final surface lineaments have been extracted. The final
lineament map has been divided in to two maps; local lineament map which was checked
in the field and regional lineament map which was confirmed by geophysical data
(seismic and gravity data). Local lineaments are evaluated in order to extract further
information on the spatial distribution and nature of the lineaments. For this purpose
lineament density, length, and lineaments intersection maps are prepared. In addition; the
field work was carried out to verify lineaments resulted from satellite images with the
observed fractures on the ground through visiting of 17 stations around the Tawke
anticline. Orientations of local lineaments (frequency and length) obtained from satellite
image were compared with the orientation of fractures (frequency and length) that
obtained from the field, using rose diagrams which show a similarities between them, as
being concentrated in NE-SW, NW-SE, E-W and N-S, as well as these Lineaments
reflect a set and systems of fractures with in studied outcrops. Two types of fractures are
recognized one are shear fractures and second are tension fractures. Stereographic
projection figured out for confirming the direction of fractures in the field and analyzing
the paleostress direction within studied area.
Geophysical data (gravity and seismic) have been used for confirming the
regional lineaments. Integration has been made between satellite image lineaments and
lineaments appeared in geophysical data (gravimetric and seismic lineaments) , there is a
coincidence both in the positions, length and azimuths of gravimetric lineaments, seismic
lineaments and lineaments appear on satellite image (i.e. surface lineaments). It has been
observed that two mechanisms are responsible for giving the architectural shape of study
area one is due to block-faulting related to basement faults activity from at least the
Middle Paleozoic and continued intermittently up to Late Tertiary, while the second
mechanism is due to compressive horizontal stress that have been active since Middle –
Late Cretaceous continued up to Late Tertiary.