Abstract:
The major karstic area in Libya known as Ayn Zayanah system is a unique phenomenon of concentrated karstic surface and subsurface dolines and channels.
By focusing on Al Majdoub Lake, as a case study, we can better understand how lithology, structure and hydrology contribute to the regional formation of the Karstic system.
Geologically, the limestones of the middle Miocene, Benghazi Formation is forming the northern side of Benghazi region, which is characterized by well-developed surficial, interface, surface and subsurface karstic features that are open or filled with sediment. The formation of Ayn
Majdoub doline is filled with saline water, which is attributed to the dissolution of a buried
carbonate layer by fresh groundwater due to the drop of the Sea level and the associated
groundwater levels. This is combined with epeirogenesis movements, which have caused the
development of karstification to reach a depth of 130-150 m below present sea level in the
Benghazi plain. Through this Karstic system, groundwater seeps from Benghazi Basin towards
the Ayn Zayanah (The Spring) and then to the Blue Lagoon (The Lake) finally to the sea.
