At present, little work has been done on the Cyclostratigraphy of the Abidjan margin, so the base level, which is a dynamic surface controlled by factors such as (tectonics, eustatism and climate), represents a very complex environment, which makes it difficult to characterize its rise or fall. This study aims to determine the major lithological ensembles with the evolutionary trends of the logs. The studies carried out concern the analysis of two boreholes located on the Abidjan margin, In this paper, the INPEFA technology of Gamma-Ray logs was used to study the cycle of deposition systems. The negative trend in the INPEFA curve indicates the half-cycle of sea-level decline, the positive trend suggests the rise in sea level of another half-cycle. This allowed us to determine respectively a negative trend, dominated by a positive trend and symmetric cycles (negative trend-positive trend).
This study is part of the development of sands and gravels in the locality of Attiékoi (south-east of Côte d'Ivoire) in public works technique. The objective is to determine the lithological and geotechnical characteristics of the formations in order to assess the depth, extent and quality of the gravel deposit to be exploited. After the lithological characterization and according to AFNOR standards, geotechnical tests were carried out on the samples. These are the sieve size analysis, the Atterberg limits, the modified Proctor, CBR and VBS tests, the sand equivalent, the specific gravity, the apparent density, the Los Angeles, the Micro-Delval and chemical analyzes. (Magnesium, Calcium, Salinity). The results revealed six lithological units, including coarse-grained sands, mottled clays, conglomerate formations, gravelly sand, lateritic clay and bar earth. The geotechnical characterization testifies to three preponderant classes of aggregates (fillers, sands and gravel). These tests show that these materials do not meet the minimum specifications and cannot be suitable for public works.
Two ternary diagrams were constructed according to the distribution of granulometric sizes in the mixed terrigenous clastic sediments and sedimentary rocks starting from some classifications and sedimentological definitions. These diagrams are: ternary diagram SSC and ternary diagram GSM. The poles of diagram SSC are occupied by the sediments "Sand", "Silt" and "Clay" and those of diagram GSM by the sediments "Gravel", "Sand" and "Mud". These diagrams make it possible to differentiate three terrigenous clastic sediments and sedimentary rocks types: proper sediments and rocks, mixed sediments and rocks with two elements and mixed sediments and rocks with three elements.
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