A Gravity Survey and Data Interpretation of Tawke Structure (Iraqi Kurdistan Region)


In this study 780 gravity measurements were conducted in the Tawke area along the paved and accessible unpaved roads. The obtained gravity data was subjected to the necessary corrections and analyses qualitatively and quantitatively. For that purpose the Bouguer anomaly map was transformed analytically to regional and residual fields. Moreover two profiles trending NS were limited to a 2-D gravity models. The main structural features of the studied area as are recognized utilizing two main lines of evidence, namely, geological map and geophysical interpretations have one distinctive trend; it is the E-W Taurus trend. The Bouguer map of the Tawke area shows gravity high in the central part. It trends E-W. It is indicative of the main anticline. Two gravity lows indicating the two synclines bounding the structure from north and south are clearly shown. Six faults are inferred from gravity data. When inferred faults and gravity lows and highs are plotted on the geological map they show good agreement.A considerable density contrast of 0.36 gm/cm3 was observed between the Jeribe, Ana, Pila Spi, and Avana formation group against Lower Bakhtiari, Upper Fars and Lower Fars formation group and used in the modeling of two profiles. One main positive and two negative features characterize these profiles. The positive anomaly represents Tawke Anticline, the south negative anomaly represents Khabore syncline and the other Zakho syncline.Geological model for profiles show that the Tawke Anticline is an asymmetrical Anticline producing a structural trap by tilting of the Miocene formations comprising sealing rocks (Fatha Formation) and reservoir rock represented by the Jeribe carbonates. Two small faults on the northern limb of Tawke Anticline have indications on the surface as seepages of oil.