الملف ١٤٥٠\١٩١٩ "بلاد الرافدين وكردستان: تقارير جيولوجية عنها" [و‎‎٢‎١‎٧] (٥٢٢/٤٦٤)

Report on the prospects of obtaining Oil in the Jabal-Hamrin and
\
By E. H.
Jabal-Makhul between Tikrit and Sharqat.
PASCOE, D.Sc., M.A., F.G.S., Supdt., Geological Survey of
MAPS. 1 in.
i in.
T.C. 227a and part of T.C. 248.
T.C. 173, T.C. 225 and part of T.C. 171.
INTRODUCTION.
On my way up from Tikrit to Qaiyarah the oil indications at Fathah seemed of such importance
as to warrant an extended examination before passing on.
The Jabal-Hamrin is a long narrow range projecting from the alluvial plain, and extending from
Fathah on the Tigris south-eastwards for over 100 miles to the latitude of Shahraban, and across
the river north-westwards for another 37 miles under the name of the Jabal-Makhul. The portion under
report is that between Ain Nukhailah, 26 miles E.S.E. of Fathah, and Khan Sultaniyah, 23 miles
N.W. of the same ancient city and 10 miles S. of Sharqat. The portion of the range delimited is
extraordinarily simple and regular, varying from 2 to 2^ miles in width ; the highest point of the
Hamrin is some 600 feet above the river, while that of the Makhul is probably nearer 800 feet.
With the exception of the Tigris gap, this section of the range is not only unbroken, but its crest
follows very closely the rise and fall of the anticline of which it consists, producing an unbroken
gently undulating sky-line. The Tigris evidently cuts through the range in a weak spot caused by a
considerable local sag in the anticlinal crest combined with a change in the direction of the axis from
E.S.E. W.N.W. (more accurately 62° W. of N.—62° E. of S.) on the left bank, to N.W.—S.E. on
the right bank. A sigmoidal curve at Ain Dibs further relieves the monotony.
There is not a single tree in the area or within sight of it, and that po.rtion immediately E. of
Fathah is particularly barren of grass ; towards Ain Nukhailah grass is more plentiful and water less
scarce though slightly brackish. The Jabal-Makhul also supports more vegetation. Small brown
partridges like the Punjab Sisi are plentiful, especially in the Makhul, and a few of a larger kind,,
similar to the Indian Chikhor, are to be found on the higher slopes ; these and their usual companion,,
the Fox, are the only forms of animal life to claim attention.
Exposures are excellent. The ground is much dissected by streams and walking wearisome but
not difficult owing to the softness of the strata. The topographical maps available are very sketchy
and at times inaccurate, especially in their contours, but they serve to show in a general way the
structure of the area. The geological boundaries, it is hoped, are as accurate as the maps permit.
The Alluvium is troublesome in concealing the Tertiaries and has been omitted where possible ; to
put in the true alluvial boundary would necessitate a separate map. An attempt has been made ta
separate the red clays and sandstones from the sandstones and conglomerates, in the upper of the
two Tertiary series.
ROCKS.
The rocks comprise a central core of gypsiferous beds belonging to the Lower Fars, flanked on
each side by a series consisting of red clays and sandstones passing up into sandstones and con
glomerates. The Mesopotamian Alluvium conceals much of the latter series, but scarcely any of the
Lower Fars. Recent gravel is common, and an older conglomerate, probably of Pleistocene age,
occurs in small patches at considerable heights near the river.
Lower Fars. The predominant constituent of the Lower Fars stage consists of white opaque
gypsum, sometimes homogeneous and of a high state of purity, reaching thicknesses of 40 50 feet,,
at other times stratified with numerous thin lamellae of clay. This deposit is characterised by many
underground caverns leached out by percolating water and sometimes se\eial yards deep, which
produce the hollow sound so noticeable when walking on these beds. It weathers in the peculiar
way often seen in the case of a homogeneous limestone, the surface becoming scoured by numerous
round-sectioned channels like those produced by a cheese-scoop. Although such a comparatively
soluble mineral, it resists weathering more than the associated beds of clay ; in fact its resistance to
erosion is somewhat surprising. More than half of the Hamrin range consists of this deposit which,
there is every reason to conclude, is a sedimentary one. Associated with it are thin bands of limestone
which may be comparatively solid and crammed with obsctrre shells, especially of a small pelecypod,
or may consist of a cellular rock identical in appearance with Cunningham Craigs detrital lime
stone’' of the Maidan-i-naftun oilfield of Persia. 4he latter rock presents the appearance of having
been formed of comminuted shell-fragments which have lost their original organic ornamentation and
outline, but which are still separated by the original but modified interstices which divided them at
the time they were strewn along the bed of the sea ; this is the actual oil-bearing rock in the Maidan-
i-naftun field, thednterstices being filled with oil. In both banks of the river and in some of the
small water-courses around Fathah, limestones of this nature are found seeping tarry oil and bitumerm^T'
Occasionally recognisable specimens of Pecten and Ostraea are observable in it. East of FathSQi
there is probably not more than a total of 50 feet of limestone in separate bands exposed , but ih,R
the Jabal-Makhul a distinct increase in the amount and a corresponding increase in the steepness and
ruggedness of the cliffs are discernible. • - f ®
* •* * .•
• >