The caves that are present within the Injana Formation
(Upper Miocene–Pliocene) which sometimes extend
to be hosted within the Dibdibba Formation (Pliocene–
Pleistocene) in the Tar Al-Najaf and Tar Al-Sayyed within
the Najaf–Karbala district have been studied. The study
aims to assess the genesis of caves and diagnose the factors
affecting the building and the destruction of these caves
through geologic time. For this reasons, intensive fieldwork
as well as the mineralogical composition and microscopic
interpretation were achieved to facilitate the investigation of
cave-forming factors. Calcite, quartz, feldspar, dolomite, as
well as clay minerals are the constituents of Injana Formation
in the study area. The amount of insoluble residue is
usually higher in weathered carbonates and in some other
cases in fresh carbonate, which is not very common but it
may occur. Caves appear to be hosted within the claystone
beds and concentrated within Injana Formation, whereas the
Dibdibba Formation seems to form the roof of the caves.
The mechanism of building caves starts by microdissolution
forming microfractures. Then with time, they have developed
to be vertical joints.These joints were gradually enlarged
as a result of claystone exfoliation along joint planes.
Chemical weathering, physical weathering, and sedimentary
structure (mud balls) play a key role in the processes of cave
evolution. Some caves appear to be irregular, but others tend
to be regular with rectangular shape, enough for hosting
human beings. These caves may have been used as homes
for the ancient human for his protection and improvement ofhis life. At the same time as the caves were formed, there
were other natural factors working continuously that destroy
the cave. These factors are dissolution, soil creep, and
mass sliding. This work highly recommends for further
contributions in terms of the archaeological investigation
on these caves to discover the ancient civilization in this
area, if any.
صالح محمد عوض | Salih Muhammad Awadh | 11379