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The
Jiddat plateau Most of the Sanctuary is a very flat limestone plateau
known as the Jiddat. The limestone was laid down 20
million years ago on the seabed, but it is now over 150m
above sea level. Sand dunes reach out from the Ar Rub al
Khali (Empty Quarter) across the northern part of the
Sanctuary. |
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Escarpment
To the east the limestone plateau ends dramatically at the
Al Huqf escarpment, which drops 100m in places. Much of the
Depression is a very salty plain (or sabkha) in which there
are outcrops of rocks of almost every age, including the
oldest rocks in Oman (over 730 years old), making this an
area of great interest to geologists.
Tropical sea
70 million years ago Oman was covered by a warm shallow sea
that was full of life. Some of the most prolific creatures
were the rudists: cone-shaped molluscs that often lived in
colonies forming shallow-water banks. A fossilized rudist
bank can be seen near the Al Huqf escarpment, south of
Saiwan in Oman.
Forest land
280 million years ago, as Oman moved towards warmer
latitudes, the climate warmed up and the ice sheets melted.
Winding rivers flowed slowly across the plains with large
trees growing on their banks. Tree trunks were sometimes
trapped in the river sediments and fossilized. Today fossil
wood is found in the Sanctuary.
Polar glaciers
300 million years ago Oman was in subpolar latitudes. The
climate was very cold and ice sheets and glaciers covered
the land. At Wadi al Khlata a glacier eroded a vast area of
flat rock or ‘glacial pavement’. The parallel grooves were
scored by rocks trapped and moved by the ice. |
