TITLE:
Study of the Geochemistry, Mineralogy and Morphological Organization of Soils in the Northwest Region of Ngaoundere, Adamawa Cameroon: Identification and Characterization of a Paleosol
AUTHORS:
Dalil Adoulko, André Sini, Isaac Daama, Abdoul Aboubakar, Simon Djakba Basga, Béral Djetenbé, Bahouro Arka, Bello Hamagourdo, Rigobert Tchameni, Jean Pierre Nguetnkam
KEYWORDS:
Darang Soils Characterization, Paleosols, Toposequential Organization, Clay Minerals, Adamawa-Cameroon
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.14 No.2,
February
14,
2026
ABSTRACT: The study of a pedological sequence in Darang allowed to characterize the soil in the Northwest of Ngaoundere. After a description of the landscape, a toposequence of approximately 1050 meters long was the subject of this work. For this purpose, three pedological pits were opened following the toposequence in order to discover the internal organization of the soil and to allow their characterizations. 18 soil samples were collected from the center of each horizon, described and analyzed at the morpho-structural, physico-chemical, mineralogical and geochemical levels. The physico-chemical analyses were conducted according to standard methods; the mineralogy is determined by X-ray diffraction (XRD) and geochemistry analysis by ICP-AES. The results of analyses reveals that the soils of Darang are made up of two distinct organizational levels: 1) On the surface, the moderately differentiated soils formed on basaltic materials occupy the upper part of the profiles; they are brown (7.5YR 3/4), very clayey and with a lumpy to polyhedral structure; 2) In depth, the paleosols, thicker, well-differentiated soils, formed on ancient granitic materials, which occupy the lower part of the profiles; they are dark brown (7.5YR 4/6), clayey and with a polyhedral structure. Generally, these soils have an acidic to neutral pH, with low exchangeable base contents, a low saturation rate (20.01%) and a low Cation Exchange Capacity (51.04 meq/100g). The most dominant oxides are: 35% of SiO2, 20% of Al2O3) and 15% of Fe2O3). The assessment of the degree of alteration shows that the alteration is intense and discontinuous along the soil profiles. Quartz, feldspar, kaolinite, gibbsite, goethite and hematite constitute the mineralogical assemblage.