Data in Brief (Jun 2024)
Geochemical dataset of alluvial sediments in the Mbiame floodplain (NW Cameroon): Implication for provenance, paleoweathering, and maturity
Abstract
To identify potential heavy minerals in the Mbiame floodplain in the Northwestern region of Cameroon, geochemical and petrographical data from alluvial deposits were utilized. The grains are mixed with inclusions of zircon and ilmenite, and the megacrysts come from felsic to intermediate igneous rocks like old basalt-andesite and magmatic gneiss. The Mbiame region lies between latitudes 6° 8’ and 6° 24’ N and longitudes 10° 39’ and 10° 57’ E, East of Mount Oku. One of the principal volcanic massifs on the Cameroon Volcanic Line (CVL), Mt. Oku is situated over a basement composed of migmatites, biotite diorites, and Pan-African granite-gneisses that date back to 600 Ma.The Mbiame Floodplain is located in the Pan African Fold Belt, which is made up of the Benin-Nigeria belt, which is a component of the Central African Fold Belt, and the Trans-Saharan belt. Between the Congo and West African cratons is a heavily eroded and deformed combination of Neoproterozoic plutonic and volcanic arcs and Paleoproterozoic micro-continents. The Central Cameroon Shear Zone serves as the primary lineament for the Pan African Orogeny, which is structurally separated into the Northwestern Cameroon Domain (NWC), the Adamawa-Yade Domain (AYD), and the Yaounde Domain (YD) in Cameroon.The field work was carried out during the dry season. During the field campaign, numerous bulk sediments were sampled from three (03) pits of vertical lithological succession along the left terrace of the Mbiame plain and twelve (12) were selected for laboratory analyses. The criteria for sample collection were based on texture (grain size) and color parameters. To identify the heavy minerals in the sediments and to understand the source of the sediments, the selected 12 bulk samples from the different layer of the pits were dried and sieved for heavy mineral determination. Heavy mineral separation was performed on about 2 g of the concentrate using bromoform liquid and the retained heavy minerals were mounted and observed under a petrographic microscope for optical properties identification.Twelve (12) bulk sediment samples weighing 100 g each were ground up in a mild steel pulverizer before being examined for major and trace elements. At Acme Analytical Laboratories Ltd., Vancouver, Canada, the geochemical study was carried out utilizing a combination of mass spectrometry (ICP-MS) for trace elements and inductively coupled plasma emission spectrometry (ICP-ES) for significant oxides. Lithium metaborate/tetraborate (LiBO2/Li2B4O7) flux was combined with 0.2 g of sample in crucibles, and the mixture was fused in a furnace. After the beads cooled, they were digested in ACS-grade nitric acid and then subjected to ICP-MS analysis. To calculate loss on ignition (LOI), a sample split at 1000 °C was ignited, and the weight loss was then measured. Data of this paper are further presented and discussed in Etutu et al. [1].
