File 1450/1919 ‘Mesopotamia & Kurdistan: Geological Reports on’ [‎68r] (150/522)

Geological Report No. 2
v'
PRELIMINARY NOTES ON THE JABAL HAMRIN.
INTRODUCTION.
These notes have been made for the use of other geologists who may work in this country and
it must be borne in mind that very little of the enormous area occupied by this range of hills has
been seen by us at the time of writing.
The Jabal Hamrin which is the name given to a range of hills which is one of the most
prominent features of northern Mesopotamia, extends from a point about 50 miles south of Mosul
for a distance of some 150 miles to the south-east. It crosses the River Tigris near Fatha, then runs
across desert until it is cut through by the Diala River in the neighbourhood of Qizil Robat; to the
south of that place it extends some 15 miles further to the S.-E., and then merges into other hills.
Everywhere it forms a most prominent feature, rising abruptly out of the plain to a height of 1,000
feet in places.
GEOLOGICAL FORMATIONS AND STRUCTURE.
Up to the present we have crossed the Jabal Hamrin in only three places, namely, at Fatha,
where the Tigris cuts through it ; at its extension the Jabal Makhul where the Mosul road crosses
it: and between Table Mountain and Qizil Robat. In the Tigris Region the Lower Fars Series is
exposed, consisting of gypsum, marl and limestone. The beds appear to correlate with those
described in the Geological Report No. 1 on the District of Qaiyarah. At Fatha the anticlinal form
of the hills is clearly seen and the form of the hills has been determined by the form of the
anticline. The flanks of the anticline have a dip of about 30 degrees and there is no marked
difference in steepness in the two flanks. The axis of the anticline runs N.-W.—S.-E, and in the
region of the Tigris and to the N.-W. is about horizontal. Messrs. Porro and Kissling state that
where the Tigris cuts through it, the axis is plunging to the S.-E., but we were unable to confirm
this.
In the neighbourhood of Qizil Robat, about 100 miles south-east of the Tigris, the Lower Fars
Series is not exposed at all being completely buried and covered by beds of the Upper Fars Series and
Pliocene Beds (The Lower Bakhtiari of Persia).
UPPER FARS SERIES.
Consists of alternations of friable greenish or grey sandstones and red marls, the sandstones
predominating. In the sandstones at some places are found small pebbles of chert limestone, etc.
In one place an old shore line was found and on it a mammalian bone. The skeleton of a large
animal was found in the sandstone when a cutting was being made for the railway : from a fragment
examined by us, it is possibly Equus. In many places the sandstone contains fragments of the red
marl. Thin veins of gypsum occur in red marl in one place, on the crest of a fold.
About 1,500 feet of this series is exposed here and as the thickness of this formation is known to
be 2,700 feet thick in Persia, it is probable that the Lower Fars Series is some 1,000 feet below the
level of the plain. The lowest beds of the series here are very similar to the highest beds seen in
the Qaiyarah region.
PLIOCENE BEDS (LOWER BAKHTIARI BEDS).
Consist of a thick series of red marls with thin intercolated beds of grey sandstone. They
have the same strike and dip as the underlying Upper Fars Beds and appear conformable, but it is
most probable that they are uncomformable, having been deposited in a basin against the Upper
Fars beds. To the north of Qizil Robat can be seen another range of hills in which the beds have
a dip to the S.-W. f.e.ythe reverse dip to those of the Jabal Hamrin. The thickness of the Pliocene
Beds in the Jabal Hamrin is estimated as 5,000—6,000 feet.
The Section attached shows that on the south-west side of the Jabal Hamrin the Beds of the
Upper Fars dip steeply to the S.-W., in places the strata being vertical. It is likely that this steep
folding is accompanied by faulting or overthrusting, but no evidence was found. Within a distance
of 600 yards the dip has changed to N.-E. 15—20 degrees, and this dip persists right across the
range of hills.
This fold, on the south-west side of the hills, can be seen to pitch to the south-east.
INDICATIONS OF OIL.
In only one place in the Jabal Hamrin is there any definite indication of oil, as far as is known.
At Fatha, where the Tigris cuts through the hills, oil seeps up in two places in the river on the right
bank. On the left bank there are a number of small springs of water heavily charged with sulphur
gas. * The lowest exposed bed here is a massive gypsum, which has many veins of an asphaltic
substance, probably Grahamite, in it.

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