'THE GEOLOGY AND MINERAL RESOURCES OF DHUFAR PROVINCE, MUSCAT AND OMAN' [‎28v] (46/96)

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Mesopotamian depression . .. (Eocene, Ears series . . . salt ur-
rences). The “empty quarter” is . . . the continuation of the Meso
potamian geosynclinal trough which here suggests a folded structure
in the subsoil concealed by the mighty dunes ; this conception there
fore accords well with the folded structure of Qatar and ie airein
islands... It may be assumed that these Rub-al-Khah folds
diminish . . . towards the South Arabian border land of Hadramaut.
59 In the case of Dhufar, whether it belongs to Picard s
‘arabo-somali table’ or is part of the ‘foreland’ south-west of the
Oman arc of folded strata, it is only possible at present to say that
ancient (pre-Cambrian and Archaean) rocks show up around the
coast between Ras Nus and Murbat as a worn-down plain which
appears to tilt towards the scarp of the Jabal Samhan. In the
strip between the Archaean plain of Murbat and the edge of the
Samhan plateau sedimentary rocks, evidently unaltered by meta
morphism, are present. Their age is not known, but they are
suspected to be upper Palaeozoic (Carboniferous to Permian) to
perhaps Mesozoic (Trias to Jurassic) and possibly the equivalents of
Tees’ Hatat Phyllites. They are overlaid by brownish limestones
with middle Cretaceous marine fossils, but this is at the western
edge of the sedimentary strip. In the scarp itself the equivalents of
the Hatat Phyllites (Tees’ Murbat Sandstone) are overlaid, with a
slight discordance of bedding, by unfossiliferous limestones which
are, on the evidence of the Cretaceous fossils already mentioned,
believed to represent upper Cretaceous to Eocene marine deposits.
I was not able to discover any zones of shearing north of Murbat,
but the Murbat sandstones dip very steeply away from the pre-
Cambrian rocks of Jabal Ali (north of Murbat) and at the eastern
end of the bay immediately north of the Jabal Ali.
60. Elsewhere in Dhufar, except up the wadi A seasonal or intermittent watercourse, or the valley in which it flows. Nagar Ghaiz,
9 miles west-north-west of Risut, Eocene limestones are present,
with a covering of Pleistocene to Pliocene Miliolite limestone along
the coastal belt of the Jurbaid or Dhufar plain. These Eocene
limestones appear to have a gentle overall inclination to the south
west and also to be arched in the Qara mountains (Jabal Qara).
Facing the plains and at either end, Takah and Risut, there is a
seaward dip, well seen at several places between Murbat and Takah,
and again at the debouches of the wadi A seasonal or intermittent watercourse, or the valley in which it flows. Rizat and of the Arbat, etc.
Within the Jabal Qara the dips suggest very gentle folding parallel
with the watershed, but these details are visible in several places
and have not been properly sifted. On the northern side of the
watershed, A1 Qutun, in the area of Qarn Shaiba the limestones
appear to dip gently northwards. There is thus evidence of a large,
flat and extensive arch (anticlinal) along the trend of the Qara
mountains, roughly east-north-east to north-east. This is in general
agreement with Picard’s ‘arabo-somali’ zone, and thus the question