WEATHERING OF LIMESTONE BEDS AT THE GREAT SPHINX

The weathering characteristics of the sphinx limestones are evaluated in the context of their pore system. The latter consists of "ink-bottle" pores. This pore system varies from one stratum to another. In the lower micritic rocks the large cavities of the ink-bottle pores are interconnected through the fine capillary network of the narrow throats. In the upper skeletal-rich rocks the interconnections are provided by large as well as small throats. The pore systems in these limestones reflect the depositional regime as well as the diagenetic alterations. The development of microspar from the micritic mud resulted in the formation of microporosity, and the extended circulation of freshwater enlarged some micropores preferentially, forming large cavities. The relationship of micro- and macropores has strongly influenced the weathering of the sphinx rocks. © 1990 Springer-Verlag New York Inc.