Abstract
The West Congo belt contains Paleoproterozoic and Neoproterozoic Units which are deformed during Panafrican event. The Neoproterozoic Unit contains rift and post rift deposits. The rift formation is made of metabasite, volcanic and volcano-sedimentary rocks. The metabasite constitutes the Nemba Complex which is considered put into place in a continental or oceanic context. Samples from Nemba Complex collected along the “Congo ocean railway realignment” are analyzed. Major elements indicate a low potassic subalkaline affinity of the samples. Classification diagrams based of major elements shows that the rocks are a tholeiitic serie constituted of andesitic basalts, sub-alkaline andesitic basalts and a sub-alkaline to alkaline basalts. Some samples with a calc-alkaline signature indicate a crustal contamination. The traces elements plots indicate that the rocks are the MORB. The spectrum of multi-elements is characteristic of continental rocks with a lithospheric origin. This is an agreement with many works on the Nemba Complex and the alkali plutons and acid volcanic rocks associated which attribute there a rift context.
Highlights
IntroductionIt represents the east part of the Araçuài-West Congo (A-WCO) belt
The west Congo belt is made of Paleoproterozoic and Neoproterozoic units deformed during Panafrican event
The studied basic samples come from the Nemba Complex considered synrift Neoproterozoic formation dated at 915 ± 8 Ma age SHRIMP gotten from meta-gabbro zircon, [5] and associated with volcanic and volcano sedimentary rocks of Kakamoeka Subgroup whose equivalent called Mayumbian Group is dated in DRC between 920 ± 8 Ma and 917 ± 14 Ma [7]
Summary
It represents the east part of the Araçuài-West Congo (A-WCO) belt. The west Congo belt is made of Paleoproterozoic and Neoproterozoic units deformed during Panafrican event. Paleoproterozoic units of the west Congo belt are represented by Guéna formation and Loukoula and Bikossi groups [4] [5] called Premayombian Group [5]. It included granitoid and metasedimentary rocks reactive during Panafrican orogenic event. Neoproterozoic is made of rift and post rift deposits represented from bottom to top by Sounda Group (Nemba Complex, Kakamoeka Subgroup, Mvouti Subgroup) and Mayombe Group (Moussouva Subgroup, Lower Tillite formation and Louila Subgroup) [5]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
