File 1450/1919 ‘Mesopotamia & Kurdistan: Geological Reports on’ [‎204v] (439/522)

dip in both is 25° in an E.-N.-E. direction, shewing considerable reversal ; the junction appears
normal, the beds of the newer series consisting of the Red Clays characteristic of the lowest
horizons. We have here, therefore, a tight, compressed, overfolded, contorted isocline, the
overfolding being in the direction of the folding movement, i.e., to the S.-W. Small slips and faults
are seen in the S.-W. limb where small minor wrinkles have given way under the compressional
strain. I have tried to illustrate in a somewhat diagrammatic way the type of fold in sketch-section
B.-B.
Proceeding N.W.hvards from the Panj Ali area, we find the arch of the crest disappears, and,
judging from the narrowing outcrop and sinking topography, the fold pitches. Two miles S.-E of
Kirkuk it commences to rise again, but the dips are all N.-E.’ly and the Lower Ears outcrop is
invaded by the Alluvium. At Shoran is a small exposure of Sandstone dipping S.-W., succeeding
vertical and contorted Lower Ears beds.
At the oil locality the anticline seems to be a little more open. In a traverse from N.-E. to
S.-W. the dip in the Lower Stage of the Red Clay and Sandstone series is again seen to diminish
from 50° to 25° towards the Lower Ears outcrop, but to steepen abruptly immediately above the
latter series. Dips of 50° and 45° characterize the N.-E. limb of the Lower Ears, and a distinct
arching over of the beds takes place immediately N.-W. of the oil seepages, followed by
S.W.’ly dips of 28° and 45°, after which everything is concealed by Alluvium. This arch is fairly
acute and rises and pitches rapidly producing a succession of small dome-areas, three at least of
which can be distinguished N. of the oil occurrences. Very little of the S.-W. limb is to be seen,
but it seems probable that the arch described is the crest of the main anticline. Presumably steep
and probably reversed dips succeed the visible S.W.’ly dips beneath the Alluvium, but the fold
js evidently not quite so tightly pinched as it is to the S.E., and the structure a little more
favourable for the storage of oil.
North-Westwards beyond the series of domes the S. W. limb is perhaps represented by vertical
beds, but no certain crest can be seen until the fold pitches at Amshahr ; here W.’ly and S.W.’ly
dips are observable and beds can be seen swinging round from one flank to the other. Before
Amshahr is reached, the anticline curves round from a N.W.—S.E. direction towards the W.N.-W.,
then again N.W. to Qush Qair, and again W.N.-W. to Amshahr. At Qush Qair the narrow belt of
Lower Ears is succeeded on the S.W. by almost horizontal red clays and sandstones, so that the
anticline is here very compressed and perhaps fold-faulted at the boundary between the two series
of rocks, the general dip in the Lower Ears being vertical or steep.
PETROLEUM.
(/) Natural Occurrences .—The oil seepages, which are very ancient, occur some 5 miles
N.W. of Kirkuk and are exploited by an arab who is said to get 48 kerosene tins full of oil per day.
Many pits have been dug, some 15 to 20 feet deep, some much smaller, and the black tarry oil is
skimmed off the surface of the water which collects in them. There is the usual accompaniment
of sulphuretted hydrogen and a small deposition of sulphur. South of the stream which here
breaks through the hills, tarry bitumen and bituminous earth are seen along the road and on the
banks of the stream, these and the exploited oil seepages N.W. of the stream occurring close to the
line of the anticlinal crest and a little N.E. of it.
South-East of the stream and N.E. of where the crest line should be, is an oval patch of Hat
bare ground, evidently once a shallow pool, from which emanates sulphuretted hydrogen in
considerable quantity. This gas has been at some time ignited—probably artificially as I doubt
whether there is any spontaneously ignitable constituent—and perpetual fires now burn there. The
rocks beneath have probably become so hot, that it would be difficult to extinguish the flames in
the ordinary way. I visited the spot the morning after a violent storm of wind and rain, and found
the fires unextinguished. Whether there are traces of phosphoretted hydrogen or some other
spontaneously combustible constituent, the bulk of the gas is sulphuretted hydrogen and the product
of its combustion sulphur diocide. It cannot be used as an illuminant for two reasons. In the
first place the flame has scarcely any illuminating power, and secondly, the fumes of sulphur diocide
would be overpowering. The first difficulty, of course, could be remedied by using incandescent
mantles, but the second is decisive enough. For the same reason the gas could not be used for
cooking purposes except by some special contrivance. But it might be used as a source of sulphur.
I have already suggested such a use for the same gas at the confluence of the Greater Zab and
Tigris, and it would, I think, be possible to develop the Kirkuk gas occurrences in a similar way
though on a smaller scale, provided no one can be persuaded to bore for oil in this area. This
proviso is made since boring would probably commence within 1^ miles of the gas-evolution, and
might possibly affect the gas-supply. If not thus interfered with, the supply for all practical
purposes may be looked upon as perpetual. It is, of course, not certain that boring would affect
the gas supply, but this contingency should be borne in mind.
There are two or three other similar bore patches in the immediate neighbourhood and also
N.W. of the stream, some of which smell faintly of sulphuretted hydrogen, and most of which
contain slightly bituminous earth.
(A) Prospects of Boring .—The seepages are of some importance and the constant evolution of
sulphuretted hydrogen not an unfavourable sign. On the other hand the structure is not ideal,
and it will be my endeavour to point out as succinctly and impartially as possible the risks that will
have to be taken by anyone undertaking boring operations in this area. Assuming that the small
domes described N.W. of the seepages are actual parts of the main anticlinal crest, the chances
are not unfavourable that the latter is, for the length of at least a mile, sufficiently intact to have
conserved any oil-pools that may exist below ; the copiousness of the seepages also predispose one
to infer that these oil pools may be remunerative, though probably not excessively so. The
principal risks to be faced arise from two factors : (i) our ignorance of the nature of the S.W. limb
of the anticline and therefore of its degree of a symmetry ; and (ii) the depth at which remunerative
oil horizons might occur. A small sketch will best illustrate how these factors affect the question.