When the Maltese Islands were solidified and became stable, their surface tilted down from the Southwest to the North-east, therefore causing the south-western coast of Malta to be uplifted to form high cliffs with the highest point being in Dingli Cliffs about 253m high. This tilt accounts for the fact that the NW side is made up of cliffs and rdum areas, while the NE side is tilted seawards with low lying beaches.
Malta is characterised with two main faulting systems that represent the effects of two separate rifting episodes. The older of the two, which is the Great fault, trends Southwest to Northeast. The other major faulting system is the Maghlaq Fault system, which extends from the North-west to the South-east. This has also been responsible for the down throw of Filfla to sea level. A horst and graben system is found North of the Great Fault.
The geological history of the Maltese Islands is mainly concerned with the Oligocene and the Miocene periods of geological time. The rocks of Malta are arranged in a simple layer-cake succession as follows:
|Upper Coralline Limestone
||at least 150m|
||0 – 13m |
||0 – 75m |
||20 – over 100m |
|Lower Coralline Limestone
||at least 140m|
Quaternary deposit is the most recent rock formation and it is found lying in certain places over the mid-tertiary rock formation. The Quaternary is the most recent formation in geological time. Its formations started about 3 million years ago and are still operating today. However, there are still disagreements about when the Quaternary really started to form. At the time during which this layer started to form, the climate was generally mild. Man first appeared during the Holocene Epoch, that is, in the second epoch of the Quaternary period.
During the quaternary, the climate changed constantly and rapidly having glacial cold stadials (periods) and temperate periods (interglacials). For this reason, the Quaternary is divided into two unequal epochs:
1. The Holocene, which is the most recent epoch, comprises the last 10000 years of warm climate, and
2. the Pleistocene which dates back to 1.8 million years ago.
(P.J. Schembri and O. C. Hunt, Facets of Maltese Prehistory)
The quaternary deposits that are found in the Maltese Islands have generally formed during the Pleistocene epoch.