By
During
2001 and 2002, the Saudi Geological Survey cave unit made four field trips to
areas in the vicinity of Al Habakah, a small settlement located 90 kms west of
Rafha, Saudi Arabia. Eleven caves were located, ranging in length from 1.5 to
390 meters, all found in the Umm Er Radhuma Formation. Regionally, the Umm Er
Radhuma Formation consists of light gray to white foraminifera-bearing,
fine-grained calcarenitic limestone, dolomitic
limestone, and dolomite with chert scattered throughout the section.
Calcarenitic and siliceous beds are common in the upper part of the formation
and dolomitized fine-grained limestone
in the lower. In the area of the Al Habakah caves, the succession includes beds
of gypsum a few meters thick interbedded with the limestone. Whereas caves in
the Umm Er Radhuma Formation farther south commonly take the form of vertical
shafts without speleothems, the caves studied in this report are often
horizontal passages or collapse-structures with gypsum or calcite formations.
Two
examples of such caves were mapped and are geologically described in this
report. Serdab Al Aqrab Al Aswad or Black Scorpion Cave is a horizontal cave
with approximately 390 meters of passages ranging in height from 60 cms to 17
meters. Large rooms filled with breakdown are found as well as low crawlways.
Gypsum speleothems in a variety of forms decorated many passages. Also found are
large caches of bones, old and recent scat of foxes, hyenas and wolves, bat
guano and many bats. Kahf Al Ramlah Al Hamra, or Red Sand Cave is a
collapse-structure comprising a 50-meter steeply sloping passage covered with
breakdown that terminates in a room 13 meters in diameter and 4 meters high.
Fine-grained limestone is the host rock of this pit, at the bottom of which a
stratum of dolomite can be seen interbedded with secondary gypsum and iron
oxides, with no sign of speleothems. A brief description of four other caves is
also given. It is noted that dissolution of gypsum may have played a large role
in the development of these caves and the authors speculate that this area may
be part of the terrain affected by the Aba Al Qur Dissolution-Collapse structure
located in the eastern extremity of the Judayyidat ‘Ar’ ar quadrangle.