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A 3-D Image of Iljaq Salt Structure, South of
Farhadi, Reza, Geological Survey of
Alborz belt extends for about 1000 kilometers
from Aras Fault (west of the South Caspian
Depression) to the south of Kopeh Dagh
in north of Iran. Miocene sediments and evaporate deposits which called Upper
Red Formation in foreland basins in the south of Alborz
nappes are simply folded so strata are horizontal to
vertical therefore rounded hills upon plains or walls of sandstone and cliffs
over hanging valleys with numerous obvious or hidden salt structures are the
most common morphs. Iljaq salt structure is formad by gypsum, salt and potash plays which are covered
by marls sandstone and conglomerates.
Iljaq is a swollen structure which its
topography in rims is higher than the center, dip of the strata near the rim is
almost 90 degrees and a vertical gypsum layer around the structure in the top
of ring shows the border of salt. According to the 
Bouguer
anomalies the center bowel is lighter than the circular marginal rim.
The origin of
pure secondary picromerite and halite in the southern
rim of structure is the primary potash beds or lenses, therefore an
intersecting radial core drilling plan was designed and done. Under ground data
show the conical structure is built by intrusion of salt into the crest of a
double plunge inclined anticline as the stratigraphic
column is stay without any change but similar flow folds are distinguishable
in potash zone.