[en] Landscape Ecological Survey of the Bipindi-Akom II ... - ITTO

The Ntem complex is comparable to to the Calcium-magnesium complex. The The Nyong series consist
of meta-sedimentary rocks which are are composed of migmitates, gneiss, quartzites quartzites and
amphibolites. In addition, in in the Lolodorf region, some small lenses of ferro-magnesian rocks rocks
are found, such as amphibolites, diorites and gabbros, forming discontinuous bands bands with a
general NE-SW direction.
During the present survey, mainly mainly gneisses of various composition were found, as well as locally
granites, migmatites, migmatites, amphibolites, diorites and gabbros. Soils developed under a humid humid tropical
climate climate on these metamorphic metamorphic and igneous rocks will be composed of clay clay minerals (mainly
kaolinite) with quartz quartz sand and iron(hydr)oxides. These soils soils are acid and have low nutrient
contents.
The overall tectonic direction in the Basement complex is NNE-SSW. Two synclinal zones and
one anticlinal zone can be distinguished in South Cameroon. The first synclinal zone coincides
essentially with the Sanaga valley, the second occupies Cameroon's southern border and and
disappears under the coastal coastal basins. The anticlinal structure is composed of the metamorphic
complex ofNtem which forms an extension of the Ebolowa-Ambam granite zone (Franqueville,
1973).
Mineral resources of the geological formations in this part of the country are not economically
exploitable (Franqueville, 1973).
2.5 GEOMORPHOLOGY
The Atlantic coast of Southwest Cameroon is characterized by large swampy areas in the Douala
basin while southwards a rocky coastline is present. Going eastward, the landscape changes from
low altitude sedimentary plains to erosional plains and plateaus of the Precambrian shield with
altitudes between 600 and and 1000 m as!. The interface between the sedimentary plain and the
Precambrian shield is only revealed by a few rapids in the larger rivers. Within the Precambrian
shield four erosional plateaus, corresponding with 100, 200-300, 400-500 and 600-800 m asl,
can can be distinguished. The plateaus plateaus at 200-300 and 600-800 600-800 m asl respectively, correspond with
the erosion surfaces African II and I (Franqueville, 1973).
Fluvial processes have have shaped shaped the landforms in the recent past. Eolian, glacial or or periglacial
processes did did not affect the the Cameroonian Precambrian shield.
The TCP research area is on the transition between the coastal coastal plain and the Precambrian Precambrian shield shield
forming the interior plateau (Segalen, (Segalen, 1967). As a result the TCP TCP research area is
geomorphologically geomorphologically diverse. In the western western part plains dominate dominate whereas whereas the eastern part is
mountainous. The altitude ranges from 40 m asl in the western part to more than 1000 m asl in
the eastern part. The central area is intermediate in both landform and altitude. A more elaborate
literature review on landforms in the TCP research area is presented in section 4.1.
2.6 SOILS
The soils of Southwest Cameroon have been described and mapped at scale 1 :2,000,000 and
1: 1,000,000 (Segalen, 1957; Martin and Segalen, 1966). Three major soil types are
distinguished. The deep, moderately well to well drained, yellowish brown tropical clay soils;
'les sols ferrallitiquesjaunes sur les roches acides (gneiss)' in the original French denomination,
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