Proterozoic time constraints on the deposit of the Mbuji-Mayi Supergroup, Democratic Republic of Congo (DRC)

摘要: The Sankuru-Mbuji-Mayi-Lomami-Lovoy (SMLL) basin, DRC, located between the Archean-Paleoproterozoic Kasai Craton and the Mesoproterozoic Kibaran Belt, includes the Mbuji-Mayi Supergroup, a sedimentary sequence unaffected by regional metamorphism and containing a large diversity of well-preserved acritarchs [1]. Lithostratigraphically, this Supergroup is composed of two distinct successions (i) a lower siliciclastic sequence of BI Group (ca. 1175 Myr to ca. 882 Myr [2] or ca. 1050 Myr [3; 4]) unconformably overlying the ca. 3.0-2.6 Gyr granitoid Dibaya Complex to the North [5] and (ii) a poorly constrained upper carbonate sequence with sparse shales of the BII Group. Basaltic pillow lavas overlying the Mbuji-Mayi Supergroup were dated around 950 Myr [6; 7]. To better constrain the age of this Supergroup, we combine different geochronological methods, in particular on monazite and xenotime which are …