File 1450/1919 ‘Mesopotamia & Kurdistan: Geological Reports on’ [‎86r] (186/522)

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some of the sandstones mav hav^
Lower Fars this deposit contains ^ )( ^ casiona ^y projected in the form of low mounds. Near the
impression of slight dip in the W p er .’ worn ^ oc ^ s white gypsum. One occasionally gets an
approximate limit of Tertiary exposures 10111 * ^ oun< ^ ary mapped is purely arbitrary being the
The New Alluvium frin Ring the river calls for no remarks.
STRUCTURE.
persistent, simple anticline. Tecon^andchne 01 rangeS coiacid e with a remarkably long and
north-north-westwards in the Tibnl-OPn ' e commences E. of the Humr Plain and continues
are not quite parallel, varies from 3i to dlstar J ce betw een the two anticlinal axes, which
Clay and Sandstone Series ^ S ’ the Synclme between bein g occupied by the Red
the N.E. As the foldh^m^ the S limb bein ^ a httle steeper than
gigantic system of loops^which constitute th^^m ^ ^ the bein ^ P art of that
mountain systems, we thus remark t f ,, ma r a ^ a ’ ^ be Afghan, Baluchistan and Persian
of movement. tendency for the fold to be pushed over towards the direction
north- westwards° The^res^oblm anticlinrsin'S"? 11161101 - 11 ^ 3t the Mukhailah Pass and proceeding
E.S.E. of which point it is seen risfns ce^ t v on to a —um close to and a little E. of this pass,
the pass the anticline, omitting sli«hHnesuIarh,>s on^^M^ 0 ^ 11 ’ r ° Und and regUlar f ° ld - Acr0SS
the outcroo of the T nwer Fore i ^ a Tr anbes on . tbe S1 de, is practically symmetrical, while
rises 0 very°graduaflj^a't ^ir^about 6 ^^- 6 '^ h ^ “ Width ' W - N ' W - of the P ass the fold
reaches a maximum altitude * Re i ,,, u ■ becoming less and less for some miles where it
fo anothe”” a er which ’ the antlckne P^ches in an equally gradual and gentle fashion
the ^''insmap 11 wherefoT ^twn 'r, U *h S a ® a,n . ® radua ^y and steadily as far as the word “Jabal” on
maximum the Lower Fa^onh-r^ ee ?s lleS , n °- perceptibIe pitch is measurable; at this crest-
gradually increasing to over S° when .j"' 6 '' , 4 . mI es 111 ' V1< -hh. It then slowly begins to sink, the pitch
g any m creas ng to oyer 5 when a point is reached about a mile from the Tons where it once
more rises very slightly, forming with a short distance of the outcrop on the west bank of the rNer
a small dome area, which ,s slightly steeper on its S.W. aspect than elsewherl and whose cen re is
° £ ,imeSt ° ne and g " bandl three of the
S^'^ste^^l-^l th c crest rises, distinctly at first, less and less perceptibly
atterwards. Persistent mist pi evented my determining the crest-maxima in this range but there
S S W of Mushak® Oppose A retC n h m ^ ediate,y d S ' ° f 0alah Jabbar ' and P erha P s another maximum
w. ot Musnak. Opposite Am Dibs there is a distinct pitch of 5° to the N N W
With regard to the flanks of the fold, the dip at Ain Nukhailah rises'to 40“ on each side
Steeper dips occur locally immediately W.N.W., but where sections B-B has been drawn the
general maximum dip on the N.E is about 3S“, that on the S.W. between 35“ and 40°. On the S.W
■ Ulk ; s ° nie 5 n " es flom . Tathah a small subsidiary wrinkle makes its appearance and persists for
about 3 miles giving vertical and reversed dips along the Lower Fars boundary • this is orobahlv
IsTery broad and gen'tle^' 1 ThiS Pit ° h ^ accompanied ^ a flattening of the arch which at Fathah
• The J abal - Mak hnl Shows considerable asymmetry at first, dips of perhaps 25° (the maximum dip
is concea ed beneath alluvium) on the N.E. being balanced by dips of 65°, 75° and 80 on the S W
Neai Jabbar the asymmetry becomes less, 27 on the N.E., and 57° on the S.W. Across Ain Dibs
we httve abou 25“ average maximum on the N.E. against 40° on the S.W., the latter flank steepenin'
rathe! suddenly towards the base of the range. Figures for Makhul must be accepted as approximate
only, the riyei on one side and the alluvium on the other marking the maximum dip. As a whole
the crest is broad and rounded in both ranges ; in longitudinal section it is also rounded.
The livei has pierced the range at a weak spot where the crest has sunk to the small low dome
between the two crest-mmima, and where the direction of the fold somewhat abruptly channel from
fh W T°h f Ar 62 ” E , °/ f- ‘ 0 , near i y d - N.W.-S.E. ; dip-faulting may hav^alsi^tt^^
this That this gap dated at least from Pleistocene times, is, I think, shown by the presence in its
neighbourhood of the conglomerate of that age.
PETROLEUM.
Natural Indications. Seepages of tarry oil and bitumen are too numerous on both river
banks around the opposite Fathah to be indicated on the map. Bitumen impregnating earth is to
be seen at various horizons, and has frequently been forced up vertical fissures. Three separate oil
horizons of seeping cellular limestone can be distinctly traced for some distance passing from one
side of the river to the other. “Gouttes” of dark oil are seen continually floating down the river
and have been collected and utilised by the Sappers ; there is a strong odour of Hydrogen Sulphide
on both banks. The water trickling from the small streams into the river are milky with suspended
sulphur, and specks and patches of this mineral are locally common in the clays and gypsum • a tarrv
oil usually contaminates this watei and there is then a confliction of the odours of hydrogen sulphide
and that of aromatic hydrocarbons. Similar indications were noticed in a stream-course 2 L miles
E.S.E. of Fathah on the S. side of the range, and others about 5 miles above Fathah on the N E
side of the Jabal-Makhul ; these are merely instances and there are doubtless others Their
particular abundance at the gap made by the river may be due to disturbance of the strata caused
by the twist in the anticline and the pitch of its axis. Seepages are frequently found where a" fold
pitches, perhaps on account of disturbance in the beds.
Prospects of Boring. Mr. James divided the Lower Fars of the large Persian Oilfield into
three zones, a, b and c, a being the oldest. The Hamrin beds seem to agree very closely with his
b zone, and as the important oil horizons occur in the cellular limestones of the lowest or a zone
there is good reason to suppose that such limestones are within easy access of the drill three at least
of these petroliferous limestones, which extend up into his middle or b zone, are evidently"repre
sented by the denuded seeping limestones on the river banks. The structure could scarcely be more