AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain
Tectonic Mapping Using Geomorphologic Characterization from Remote Sensing Data
(1) WesternGeco, Gatwick Airport, United Kingdom.
(2) Schlumberger, Cairo, Egypt.
The joint interpretation of digital elevation models (DEM) and multispectral remote sensing data in connection with stratigraphic and geologic information reveals the geologic structure of the earth surface, particularly in desert terrain. The characterization and classification of the DEM using spatial statistics provides hints regarding formation tops, which are validated by mineral spectroscopy of multispectral remote sensing data. The idea behind this approach is that the earth surface topography is the result of geological processes such as deposition, erosion, and tectonics.
In the first step, the DEM is analyzed for geomorphologic terrain class such as table land. Also, terrain edges and escarpments are extracted using a spatial gradient filter. In hard rock areas, the escarpments often delineate valleys that follow fault lines. In the second step, individual bands of multispectral satellite images are combined to form a multiband RGB image that reveals the different rock types in certain areas. The rocks exposed as outcrops can be associated with their elevation using the digital elevation model. From the relative elevations, the deposition sequence can be obtained, and hence, a stratigraphic column. When combined with the tectonic lineaments extracted from the escarpments of the DEM, tectonic features can be identified.
We have applied the methodology to a pull-apart basin in the eastern Sinai Peninsula, Egypt. Fault lines parallel to the Gulf of Aqaba left-lateral fault were identified on the surface gradient. Lithology focused processing of satellite imagery allows the distinction of Precambrian basement, Paleozoic metamorphic rocks and Mesozoic sandstone and limestone. Where the left-lateral fault system got stuck an S-shaped pull-apart basin developed. Using the geomorphologic analysis from DEM and multispectral satellite imagery the pre-erosion surface could be reconstructed and the amount of throw in the graben fault could be determined.