STUDY OF THE GRAVITY DATA OF SOUTH OF TAL AFAR AND MOSUL CITY – NE IRAQ
Ezzadin N. Baban
Dept. of geology, Faculty of science, University of Sulaimani, Iraqi
To analysis and interpretation the Bouguer anomaly map of south Mosul
and Tal Afar area studied to delineate the subsurface structures. After
the gridding the Bouguer anomaly data, several analytical methods of
regional- residual separation are used such as, Griffin method, moving
average and inverse distance methods.
Regional and residual maps were constructed. Most of the regional
anomaly maps shows large and regional high and low anomalies. These
large and wide anomalies may be reflected a high and low blocks within
Basement rocks and extended into sedimentary rocks such as Mosul block.
These blocks bounded by several deep faults having NW-SE, E-W and NW-SE
Several small scale (shallow) positive anomalies are detected which may
be reflected the effect of the subsurface anticlines within the
sedimentary cover trending NW-SE, E-W and NE-SW. These anticlines
occurred during Najd and Hejaz orogeny (NE-SW trend) and Alpine orogeny
(NW-SE and E-W, “Zagros and Torus trend”). Also, several small scale
negative anomalies are detected on residual maps which may be reflected
the effect of subsurface synclines within the sedimentary cover having
the same trends of anticlines such as NW-SW, E-W and NE-SW.
Several assumed Fault locations are referred on residual and second
vertical derivative maps too. Most of them having NW-SE trend (Zagros
trend). Also there are E-W (Torus trend) and NE-SW (Najd and Hejaz
trend). These faults are having different lengths. Some of them which
are occur within sedimentary rocks, extending into Basement rocks too.
Finally by using Wollard, 1962 equation, the depth of Moho discontinuity
(thickness of crust) map constructed. It is appear that the depth of
Moho ranges 33-35km in the area.