الملف ١٤٥٠\١٩١٩ "بلاد الرافدين وكردستان: تقارير جيولوجية عنها" [ظ‎‎٢‎٠‎٨] (٥٢٢/٤٤٧)

4
.
There being no boat obtainable it was impossible to cross the river and in
vestigate wbat looked like a continuation of the Lower Lars outcrop flanked
on the N. by Red Clays and Sandstones; such a continuation is probable.
From the Tigris the anticline rises distinctly in a crest-maximum,
miles W. of the Oil Station. W.N.W. of this it pitches at an angle which
at first is about degrees, but which soon becomes so small as to be immea
surable, and a long stretch of almost horizontal crest extends as far as the
Qishlah hills; there may be a W.N.W. by pitch along this stretch, but if so,
it is extremely slight and probably negligible. Within three or four miles
of Qishlah Fort there is a distinct rise which increases to 2J degrees. N.-W.
of Qishlah there is a pitch to the W.N.W., so that there is another crest-i
maximum close to the Fort, probably a little higher than that above
Qaiyarah. The rise in the range seen four or five miles further still to the
W.hf.W. no doubt indicates a further rise in the anticline, and according
to the map there are others beyond; owing to trouble with a local Shaikh
I was unable to work beyond Qishlah.
With regard to the flanks of the anticline, slight undulations therein, a
result of the breadth and gentleness of the fold, made it difficult to estimate
the general average maximum dip, especially on the S.W. where alluvium
conceals the steeper-dipping beds. West of Qaiyarah the average maximum
dip in the S.W. limb is probably in the neighbourhood of 15 degrees, rising
to 19 degrees or 20 degrees in the Qishlah area. On the N.E. flank the
general maximum dip is probably nearer 10 degrees or 12 degrees, but slight
puckers, caused by the weight of the rocks in such a broad gentle arch,
bring in local dips of 35 degrees, 20 degrees, etc. For practical purposes the
fold may be looked upon as symmetrical, though the Qishlah area shews a
slight steepening on the S.W.
The same “ choking ” of the stream courses noticed elsewhere, was-
observed, and extended up into the Lower Fars outcrop.
"No. 4.
PETROLEUM.
Natural Seepages .—I located four areas where seepages occur, but there
may be others.
The first is marked on the J-inch map as “ Naphtha Spring,” and con
sists of three separate patches of bitumen and tarry oil, the two upper being
connected by a stream of bitumen. It is impossible to make an estimate
approaching any degree of certainty regarding the thickness and amount of
bitumen here and elsewhere, owing to our ignorance of the irregularities in
the floor on which it lies. It is, of course, a mere surface deposit supplied
by numerous small vents up which the tar producing it oozes; the supply
therefore is an easily exhaustible one and will be replaced only after a con
siderable lapse of time, unless artificially encouraged by bombing or exca
vating. The uppermost patch of the area in question is irregular in shape,
but covers something like 100,000 sq. feet. An assumption of 6 ins. average
thickness would give 50,000 cubic feet as the amount present. The middle
patch is larger and the richest of the three, being partly covered by a lake
of wmter.. It is an oval area of about 400,000 sq. feet; the thickness is over
one foot in places, but taking one foot as the average, the amount present
would be 400,000 cubic feet. The lowest patch is not much larger and prob-
ably very thin. Assuming it to contain 50,000 cubic feet, the total for the
area becomes^ 500,000 cubic feet. It might w r ell be double this or consider-
ably. less. There are numerous small vents up which an inflammable gas,
consisting largely of hydrogen sulphide, issues, together with a thick black
tarry oil in process of being transformed into bitumen; there is every grade,
in fact, from a viscous tarry oil, through plastic tar or asphalt, to solid brittle
bitumen. Where water accompanies the oil, a pool is often formed in which
sulphur is deposited, derived from hydrogen sulphide of wFich a strong 1 odour
pervades the area. The oil from wFich the bitumen is produced by oxida
tion, is, in all probability, derived from some seeping petroliferous limestone
beneath the alluvium.. Some of the bitumen is mixed with earth, and that
of the stream connecting the two upper patches contains many pebbles. It
may be noted in passing that the solid brittle bitumen has the same appear
ance as a lignitic coal, a resemblance which seems to have originated reports
of file latter mineral at Guwarra, and may possibly be resnonsible for a similar
report respecting other localities.
„ application of heat wall demonstrate the difference, the bitumen melt
ing and cooling the characteristic odour.
The second bituminous area is close to the oil wells, and covers an area
perhaps a little larger than the first. The bitumen is thicker also and prob
ably reaches 2 3 feet in places. 1,000,000 cubic feet is probably not an
excessive estimate of the quantity here; there is considerably more
thick oil and gas. In a small w r ater-pool sulphur in some quantity has
^ected ^ le bottom; it and the water are disturbed by a curious ebullition
although very little gas. reaches the surface, the bulk probably being dis-
solyed by the water, which smells strongly of hydrogen sulphide. Oil was
collected here by the Turks, or by the Germans who w T ere in control of the'