Microfeatures and distribution of calcium carbonate in some calcareous soils of Egypt [electronic resource].

Includes references.

The aim of this work is to deal with macro and micromorphology of the forms and distribution of calcium carbonate accumulation in some calcareous soils of Egypt. Four calcareous soil profiles from El-Fayoum, Maryut, Burg El-Arab and El-Arish valley have been chosen to study the distribution of CaCO₃ in different fractions and their pedogenic accumulation in different shape , size , colour and nature. Concerning the distribution of calcium carbonate in different soil fractions, it is found in clay textured soils most of the CaCO₃ is usually found in the silt and clay fractions, whereas in the clay loam textured soils. the calcium carbonate content was rather regularly distributed over the clay, silt and sand fractions. While the sandy clay loam and sandy textured soils have the majority of calcium carbonate in the sand fraction. On the other hand, most of the active CaCO₃ content was within the clay fraction. The microscope investigation of thin sections show many shapes and different formations of carbonates. The nucleic carbonate nodules are dominant as secondary formation in the alluvial soils of Fayoum. While in the lacustrine deposits of Maryut grain carbonate cutans are the distinct phenomena. In the profile of Burg EI-Arab, many calcified shells and oolitic sands are the main components of the calcareous materials in the soil mass. Many forms of calcite have been observed in the soil of AI-Arish valley as coarse and fine mineral grains and nodules in different shapes.

Summary in Arabic.

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