Petrochemical Characterization of Two Distinct Types of Dolerites from Bafoussam Area, West Cameroon

Abstract

Two petrochemical types of doleritic dykes have been distinguished in Bafoussam area: 1) the olivine-bearing dolerites which are the most representative are dark green, showing characteristics of alkaline basalts and, 2) the calcite-bearing dolerites are grayish green, showing characteristics of tholeiitic basalts. The studied dolerites are less differentiated (1 < FeO t /MgO < 2); they present the evolution of a subalkaline magma following a calc-alkaline series (alkaline dolerites) and the tholeiitic series (tholeitiic dolerite). The chondrite normalized multielement spider diagrams of all the dolerites show a pronounced depletion in Ba, Th, and enrichment in Rb. Their geotectonic context is inferred to be intraplate and the contrast between the two types is probably due to a diverse source: crustal source for calcite-bearing dolerites and mantle source for olivine-bearing dolerites.

Petrography and Geochemical Characterization of Dolerites from Figuil (Northern Cameroon) and L&#233;r&#233; (Southwestern Chad)

“…Figuil and Léré dolerites resemble other dolerites described as continental tholeiites in Cameroon, e.g. at Dschang, Bangangté and Manjo [62], Biden [63], Mbaoussi [7], Bafoussam [5], Mayo Oulo-Léré and Babouri-Figuil [10].…”

Geochemistry and apatite U–Pb geochronology of alkaline gabbros from the Nodoushan plutonic complex, Sanandaj–Sirjan Zone, Central Iran: Evidence for Early Palaeozoic rifting of northern Gondwana

“…Major and trace element compositions were determined by ICP‐MS after 0.2 g samples of rock powder were fused with 1.5 g LiBO 2 and then dissolved in 100 ml 5% HNO 3 . REE contents were analysed by ICP‐MS after 0.25 g samples of rock powder were dissolved by four acid digestion steps (Nono, Wotchoko, Ganno, Njinchuki, & Nzenti, ). Loss on ignition (LOI) is by weight difference after ignition at 1000°C.…”