Arkell.1956.Jurassic..

CHAPTER II
THE MIDDLE EAST
THE FRINGE OF THE ARABO-NUBIAN LANDMASS : EGYPT, PALESTINE,
JORDAN, SYRIA AND ARABIA
Nubia and a further vast region of the southern Libyan Desert, with the
Red Sea Hills of Egypt, the southern tip of Sinai, and a large part of
western Arabia in the Hejaz and Nejd, form part of an ancient pre-
Cambrian crystalline massif projecting from the continental shield of
Africa. Around the fringe of the landmass, on all sides but the south-west,
successive Mesozoic formations dip away radially and are arranged in
roughly concentric rings, those nearest the landmass forming a tabular
belt, those farther out a belt of simple folds, while farther still there is an
abrupt contact with a belt of complex folds and overthrust sheets. The
tabular belt occupies most of Egypt. The belt of simple folds coincides
with deeper parts of the surrounding trough: starting in the Egyptian
oases and passing close to Cairo at Abu Roash, it runs through northern
Sinai, Palestine and Syria, and then curves round through western Iraq
and the Syrian Desert, under the Tigris-Euphrates valley and the Persian
Gulf. South of this it is lost beneath the Rub-al-Khali. It is in this
zone that the Arabian, Persian, Iraqi, Syrian and Palestinian oilfields lie,
and it formed the fore-deep of the southward and south-westward thrusting
mountain chains of Asia Minor, Persia and Oman. It stands in the same
relation to the thrust mountains and their crystalline foreland as the Indo-
Gangetic plain to the Himalayas and their foreland, peninsular India.
(See Picard, 1939; Lees, 1948.) (Fig. 40.)
THE NUBIAN SANDSTONE
Palaeozoic sandstones, with local fossiliferous intercalations ranging
in date from Cambrian to Carboniferous, are known in the south-western
Libyan Desert, Wadi Araba near the north end of the Red Sea Hills,
Western Sinai, the Jordan valley and Central Arabia. The true Nubian
Sandstone, however, is now known to be Cretaceous over by far the greater
area of its outcrop, and especially in upper Egypt and Nubia. In the critical
Wadi Qena area, east of Assiut, it alternates with interbedded marine limestones
containing ammonites and other fossils of Albian, Cenomanian and
Turonian ages, the lowest layers, resting on pre-Cambrian granite, being
Albian or possibly Aptian (Hume, 1911, pp. 120-3; Attia & Murray,
IQ
52)-
On historical grounds the term Nubian Sandstone should be retained
as a formational name, but it should be restricted to rocks of similar age
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