Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Geology

The present thesis presents the first quantitative morphometric identification of karst-related landforms at various scales and resolutions in El Baharyia-Farafra territory, in the central Western Desert, Egypt, by using the field, remotely sensed data and Geographic information utilities. Most of the study area is covered by carbonate sequences (Late Cretaceous-Late Tertiary) obviously punctuated by a hierarchy of stratigraphic discontinuities of different magnitudes, expressed in time levels. These discontinuities remark either the non-deposition (hiatus) and/or missing of lithostratigraphic interval(s) impressed by intensive paleokarstification processes (fossilized paleokarst imtervals) and or uplifting phases. Structural mapping and delineation of the main structural elements indicated the impacts of the Late Cretaceous-Middle Eocene right-laterl wrenching tectonics and mild Miocene extension with rift-related volcanics on the morphology and landform in the study area. The mappable (geographical and geological) carbonate exposures of the different carbonate sequences exhibit an amazing and spectacular karst surface morphologies including open, exhumed and denuded karst features. Among the most recognized surface karst landforms are open karst depressions (from large scale poljes and uvals down to dolines and sinkholes), swallow holes, polygonal tower and cone karst forms, blind rivers and valleys, sinking streams, subterranean drainage, water sprins, grikes and karren features, pavements and highly corroded bedrocks, residuum, and rock remnants, cave deposits, soil products and calcite re-precipitates (flowstones). The karst processes led also to the denudation and destruction of some of the exposed fossilized paleokarst surfaces giving rise to amazing meso-scale residual karst features

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