A multi-element baseline geochemical database from the western extension of the Central Africa Copperbelt in northwestern Zambia

Abstract

A stream sediment geochemical survey was undertaken in the extreme north-west of Zambia with three primary objectives: (i) to provide a baseline environmental database for an area uncontaminated by heavy industry, mining and intensive farming; (ii) to detect metal anomalies that may indicate potentially economic mineral deposits; and (iii) to provide a tightly controlled geochemical database that can be used as a standard for future mineral exploration programmes throughout central Africa. Three major geological domains underlie the studied area. These are crystalline Kalahari Group sediments. Stream sediments collected from each of the three geological domains have distinctive geochemical signatures. Relatively high values for a range of elements including uranium, thorium and yttrium were found in stream sediments within the pre-Katanga basement domain. Enhanced values of a larger number of elements are present in the stream sediments underlain by Katanga strata including significant, previously unknown, copper anomalies that warrant detailed follow-up work. The high metal values in sediments derived from Katanga strata contrasts sharply with sediment samples collected from drainage channels in areas of thick Kalahari sand, which mostly have very low values of all analysed elements. Our results suggest that it will be difficult to detect contamination of streams in the Copperbelt areas of Zambia and the Democratic Republic of Congo due to their naturally high metal concentrations. By contrast, it will be relatively easy to monitor pollution of areas underlain by Kalahari sands as these have naturally very low values of all elements. R. M. Key

Investigating high zircon concentrations in the fine fraction of stream sediments draining the Pan-African Dahomeyan Terrane in Nigeria

“…Chandrajith et al, 2000Chandrajith et al, , 2001Key et al, 2004) and Europe (Salminen et al, 2005) (Wedepohl 1995), dash-dot = average Local Older Granite value (see Table 3), long dash = Local metasediment value (Tijani et al, 2006), long dash grey = local Zungeru Mylonites (Ajibade et al, 2008), solid grey = average European stream sediment value (Salminen et al, 2005), dotted line = average Local Migmatitic Gneiss value (see Table 2). The notches represent the 95% confidence limits around the median value for each group, outlier values are shown as open circles.…”

Geochemical mapping using stream sediments in west-central Nigeria: Implications for environmental studies and mineral exploration in West Africa

“…Darnley, 1990; 52 BGS, 1990; Reimann et al, 1998;Rice, 1999;Key et al, 2004;Salminen et al, 2005; 53 Johnson et al, 2005). The resulting geochemical data are used for a range of purposesgneisses) and plutonic rocks of the Pan-African ‗Older Granite Suite' (Russ, 1957 Odeyemi, 1988;Rahaman, 1988 (that covers the southern parts of the south-western cell), including the Niger Delta.…”

Geologic and Metallogenic Framework of North Africa

“…1) were built during the main phases of Proterozoic and subsequent Phanerozoic orogenies, the break-up of the supercontinents Rodinia, Gondwana, and Pangea, and during the opening and closing of major ocean basins such as the Iapatus, Atlantic, Pacific, and Tethys (Tawadros 2011). North African geology has been extensively studied over the last few decades resulting in a wealth of geological, mineralogical, geochemical, and geochronological data, reported in hundreds of research papers, and in geological maps published at a variety of scales (e.g., Stern 1994Stern , 2002Walsh et al 2002;Ennih and Liégeois 2001;Johnson and Woldehaimanot 2003;Lié-geois et al 2003Lié-geois et al , 2005Lié-geois et al , 2013Inglis et al 2004Inglis et al , 2005Key et al 2004, Thomas et al 2004Gasquet et al 2005;Schofield et al 2006;Bendaoud et al 2008;Fezaa et al 2010;Johnson et al 2011;Fritz et al 2013; and references therein). Therefore, only a summary of major conclusions relevant to the present synthesis is given below.…”

“…It is bounded by the Paleozoic Tindouf Basin in the north, the Neoproterozoic to Paleozoic Taoudeni Basin in the southeast, and the PanAfrican, Caledonian, and Variscan fold-thrust belt of the Mauritanide belt in the southwest and west-northwest. The following summary of major geological attributes of this region is inspired from the recent papers of Schofield et al (2003Schofield et al ( , 2006, and Key et al (2004), as these reports constitute the most exhaustive and comprehensive descriptions published on this shield. Geologically, the Reguibat Shield consists of two major contrasting domains (Fig.…”