The genesis of an ocean
Around 170 million years ago an ocean spanned the width between Europe and Africa, an area where tension in the Earth’s crust was high. This gave rise to sea floor spreading in this particular ocean, resulting in the genesis of a new ocean. From that point in time Africa and Europe began to shift toward each other, altering the stress in the crust of the earth there.
New mountains take shape
Nearly 150 million years ago the oceanic crust was under so much strain that the Alps began to form. The Mirdita Ocean located there was forced to partially slide beneath the European continental crust in the region of Albania. Moreover, the stress also caused parts of the oceanic crust to be thrust on top of the European continental shelf as overlying stratum. That is a fairly unusual process. This period of tectonic activity lasted until approximately 130 million years ago. At that time the stress in the region of Albania caused powerful deformations, and led to the formation of a mountain.
The formation of a marine basin with sediments
The pressure on the plates on the mountains periphery, along the overlying stratum led to the formation of a deep marine basin. Deposited in this deep basin, were very coarse sediments and stone fragments from the surrounding mountains. They were deposited under high-energy conditions, and the resulting clasts or cobbles could be of a considerable size. These sediments form a stack that consists of several sediment layers, that is several hundred metres thick, with very coarse debris flows at the bottom and turbidities (cloudy currents) that formed at a later stage, and are thus to be found higher up. Now a portion of these deposits is being extracted as the Deja Breccia.
Deja Breccia: a show-piece of lithology
Approximately 120 million years ago, the tectonic pulse spread even further, which also put the deep foreland basin under significant strain. As a result, the sediments (including those of the Deja Breccia) were buried and subjected to pressure from the earth’s strata. They remained in this state for millions of years until the tectonic pulse subsided, and they were gradually exposed on the surface by erosion of the overlying sediments.