Sedimentary evolution and resultant geological landscapes

Abstract

Details of the subsurface geology are scarce but in Late Palaeozoic times, the Maltese Islands lay close to the Equator in the Tethys Ocean, that extended between the continents of Gondwana and Laurasia. The oldest subsurface rocks recorded offshore in southeast Sicily are Late Triassic intertidal dolomites (Gela Formation), overlain by Jurassic Black shales (Streppenosa Formation) and platform carbonate of the Siracusa Formation. The exposed geology of the Maltese Islands comprises a marine sedimentary rock sequence about 250 m in thickness, composed of limestones, marls and clays. Ages range from the Upper Oligocene to the Holocene. The stratigraphy consists of the five principal pre-Pliocene Formations: the Lower Coralline Limestone (Oligocene); the Globigerina Limestone (Miocene); the Blue Clay (Miocene); Greensand (Miocene) and the Upper Coralline Limestone (Miocene). The Quaternary is represented by a variety of marine and freshwater deposits (i.e. raised beaches and deposits from freshwater lakes and marine high stands), whereas continental sedimentation is evidenced by fluvial conglomerates; fanglomerates; slope talus; sand-dunes; cave and fissure fills; caliche and speleothems.