عنوان المقالة: Geochemical exploration using surveys of spring water, hydrocarbon and gas seepage, and geobotany for determining the surface extension of Abu-Jir Fault Zone in Iraq: A new way for determining geometrical shapes of computational simulation models
Salih Muhammad Awadh ⁎, Kamal Kareem Ali, Abbas Taha Alazzawi
الملخص الانجليزي
The Abu-Jir Fault Zone (AJFZ) is a known fault zone and, as one of the typical structures in Iraq, extends
NW-SE for a considerable distance on the western side of the Mesopotamian basin. The feature of this fault
zone on the ground surface is mysterious and unclear. Surface extension evaluation of the fault zone requires
the selection of valid parameters from among numerous geological factors. The present study focuses on the
evidence of the existence of traces of the fault zone on the surface, such as springs, sites of hydrocarbon
seepage, and geobotany, so as to employ them as tools in geochemical exploration for detecting the surface
extension of the fault zone. For this purpose, direct and indirect geochemical methods including spring
water survey (SWS), hydrocarbon accumulation and H2S gas survey (HAGS), and geobotanical survey (GS)
were performed along the AJFZ. Hydrocarbon accumulations exist in many types of features. First, massive
amounts of hydrocarbons ascend upward under high pressure piercing the gypsum of the Fatha Formation
and exposed on the surface. Second, the hydrocarbon intrudes into the gypsum bed along the cleavage
plane but is not exposed on the surface. Third, the light hydrocarbon ascends from the depth with the spring
water and floats on the water surface. Anomaly in the distribution of hydrocarbon, total dissolved solid (TDS),
H2S gas emission, abnormality in growth of palm trees (such as stem curvature and overturn, dwarfism), and
the development of an isolated local aqueous environment around the springs along the AJFZ as well as
computational simulation can be used to draw the geometrical shape of the fault zone on the surface. The
surface extension of the AJFZ has been computed to be 467 km long with an average width of 48 km. This
study has conclusively demonstrated the validity of the use of geochemical anomalies along with the computational
simulation to estimate the dimensions of the fault zone.