Franck Delpomdor

Illinois State Geological Survey, Champaign, United States · Coal, Bedrock & Industrial Minerals

The Neoproterozoic Schisto-Calcaire Group (630 to ca. 580 Ma) was deposited on an extensive carbonate shelf in the margin of the Congo Craton in the Niari-Nyanga and Comba subbasins (Gabon and Republic of the Congo). It consists of three carbonate-dominated subgroups (SCI to SCIII, up to 1300 m-thick) recording relative sea-level changes. The SCIc...

Precambrian fossils of fungi are sparse, and the knowledge of their early evolution and the role they played in the colonization of land surface are limited. Here, we report the discovery of fungi fossils in a 810 to 715 million year old dolomitic shale from the Mbuji-Mayi Supergroup, Democratic Republic of Congo. Syngenetically preserved in a tran...

This study provides new constraints on the paleoenvironmental, eustatic and carbon isotopic models of the cap carbonate-like rocks of the Dolomie Tigrée Formation in the Katanga region, Democratic Republic of the Congo. The study integrates detailed lithofacies analysis combined with sequence stratigraphy to reveal the high-resolution architecture...

During the Cryogenian-Ediacaran, tectonically- and climatically-driven perturbations created sea level changes. Snowball Earth-type glaciations suggest ~500–800 m sea level fall or at least 1,000–1,500 m in eustatic sea-level change as a result of severe climate changes. However, in Central Africa, geologic evidence of such processes is lacking. In...

The Neoproterozoic Schisto-Calcaire Group (630 to ca. 580 Ma) was deposited on an extensive carbonate shelf in the margin of the Congo Craton in the Niari-Nyanga and Comba subbasins (Gabon and Republic of the Congo). It consists of three carbonate-dominated subgroups (SCI to SCIII, up to 1300 m-thick) recording relative sea-level changes. The SCIc...

The Neoproterozoic Marinoan climatic event corresponded to the Snowball Earth-type glaciation, and is commonly marked by the deposition of diamictites and by a negative carbon isotope anomaly. This event was followed by a sudden return to a greenhouse climate and a rapid post-glacial transgression with deposition of cap carbonates. Although the cap...

New detailed lithological, sedimentological, chemostratigraphic data were obtained from exploration drilling samples on the C5 carbonate-dominated formation of the Neoproterozoic Lukala Subgroup (former Schisto-Calcaire Subgroup) from the West Congo Belt (WCB) in the Democratic Republic of Congo. This formation records the last post-Marinoan sea-le...

This study presents a preliminary assessment of the petroleum potential of the Meso‐Neoproterozoic Mbuji‐Mayi Supergroup in the Sankuru‐Mbuji‐Mayi‐Lomami‐Lovoy Basin in the southern‐central Democratic Republic of Congo. This basin is one of the least explored in Central Africa and is a valuable resource for the evaluation of the petroleum system in...

New detailed lithological, sedimentological, chemostratigraphic data were obtained from exploration drilling samples on the C5 carbonate-dominated formation of the Neoproterozoic Lukala Subgroup (former Schisto-Calcaire Subgroup) from the West Congo Belt (WCB) in the Democratic Republic of Congo. This formation records the last post-Marinoan sea-le...

The Ediacaran Schisto-Calcaire Group is a ~1300 m-thick succession belonging to the West Congo Supergroup in Central Africa. In the Comba Basin, it consists of three carbonate-dominated units defined as formations (SCI to SCIII) that are unconformably overlain by clastic deposits (Mpioka Group) interpreted as a molassic formation associated with th...

In this paper, we have tested the application of magnetic susceptibility measurements in Cu-Ag-Zn-Pb-(Fe)-mineralized carbonates of the BIe subgroup (Democratic Republic of Congo) as an efficient tool for regional and global high-resolution stratigraphic correlations in the Neoproterozoic marine carbonates. To achieve this goal, we integrate the lo...

The Upper Diamictite Formation of the West Congo Supergroup is a diamictite-dominated successionvariously interpreted as a continental tillite, glaciomarinite, and glacially-influenced or non-glacial debrite. This paper presents a detailed macro- and microscale analysis of soft-sediment deformation structures in order (1) to resolve the long-standi...

The Early Neoproterozoic Era was marked by a phase of rifting along the western margin of the Congo Craton followed by the opening of the Adamastor Ocean and by the deposition of the West Congolian Supergroup in a passive-margin setting. The West Congolian Supergroup that includes the Schisto-Calcaire Group crops out in Central Africa from SW Gabon...

The upper carbonate-rich parts of the West Congo Supergroup (~ 1000–560 Ma) from the Democratic Republic of the Congo have hitherto been considered as a record of abrupt eustatic and climatic events accompanying glaciation and deglaciation of a Snowball Earth-type Marinoan ice age that was of global extent. These strata have however never been inve...

New detailed lithological, sedimentological, major chemical, δ13C and δ18O stable isotopes data were obtained from exploration drilling samples on carbonate formations of the Neoproterozoic Schisto-Calcaire Subgroup (>635-575 Ma) in the Lukala area (Bas-Congo, Democratic Republic of the Congo). This work characterizes and reinterpretes the stratigr...

In the Lower Congo region, the Ediacaran Schisto-Calcaire Subgroup consists of five carbonate-dominated formations (C1 to C5). They record tectono-eustatic sea-level fluctuations controlled by several short-time extensional tectonic events occurred in the whole basin, followed by the development of the Araçuaï-West Congo Orogen between 630 Ma and 5...

The Congo Shield is a central African large landmass with several Archean nuclei welded during the Eburnean orogeny approx. 2.1-1.8 Ga and subsequently stabilized as a coherent unit throughout late Paleoproterozoic to Meso-Neoproterozoic times. The early Neoproterozoic was marked by rifting along the margins of the Congo Shield related to the break...

The late Mesoproterozoic - middle Neoproterozoic carbonate succession (1155 Ma - 800 Ma) of the Mbuji-Mayi Supergroup (Democratic Republic of Congo) is poorly investigated with respect to sedimentology including climate, tectonics and sea level changes. In this paper, our data including microfacies analysis, sequence stratigraphy, Fischer plots cou...

The Congo Shield is a central African large landmass with several Archean nuclei welded during the Eburnean orogeny approx. 2.1-1.8 Ga and subsequently stabilized as a coherent unit throughout late Paleoproterozoic to Meso-Neoproterozoic times. The early Neoproterozoic was marked by rifting along the margins of the Congo Shield related to the break...

The late Mesoproterozoic - middle Neoproterozoic carbonate succession (1155 Ma - 800 Ma) of the Mbuji-Mayi Supergroup (Democratic Republic of Congo) is poorly investigated with respect to sedimentology including climate, tectonics and sea level changes. In this paper, our data including microfacies analysis, sequence stratigraphy, Fischer plots cou...

The late Mesoproterozoic–middle Neoproterozoic period (ca. 1300 Ma–800 Ma) heralded extraordinary climatic and biological changes related to the tectonic changes that resulted in the assembly (~1.0 Ga) and the break-up of Rodinia (880 Ma–850 Ma). In the Democratic Republic of Congo, these changes are recorded in the Mbuji-Mayi Supergroup which was...

Microfacies, isotope (C, O and Sr) compositions and REE+Y distributions are integrated to unravel the paleoenvironmental and chemical conditions prevailing during deposition and alteration (or contamination) of the Mbuji-Mayi carbonates (888 to 800 Ma). The BIe to BIIe subgroups records the evolution of a marine ramp submitted to evaporation, with...

The carbon, oxygen and strontium isotope geochemistry is the most widely applied chemostratigraphic tool in the reconstruction of paleoenvironments and indirect regional or global correlations for the Neoproterozoic times. Relatively good preserved carbonate rocks of the West Congo Supergroup, i.e. the Schisto-Calcaire Subgroup of the Democratic Re...

The Meso- and Neoproterozoic Mbuji-Mayi Supergroup (1155 Ma to ca. 800 Ma) was deposited in the SE–NW trending siliciclastic-carbonate failed-rift in the Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin. Drillcore- and outcrop-derived microfacies, isotope (C, O and Sr) compositions of carbonates and REE + Y distributions are integrated to unravel the paleoenv...

The middle Neoproterozoic carbonate-dominated uppermost Haut-Shiloango Subgroup (Sh8h and Sh8i members) in the Lower-Congo Province of the Democratic Republic of Congo is considered as recording pre-glacial shallow-marine sedimentation with stromatolitic reefs overlain by the Upper Diamictite Formation. We investigated these stromatolitic carbonate...

The focus of this chapter is the West Congo Supergroup in the West Congo Belt (WCB), which extends along the westernmargin of the Congo Craton from Gabon in the north to northern Angola in the south, and the Lindi/Ubangi Supergroup of the Lindian and Fouroumbala – Bakouma Basins exposed on the northern margin of the craton. In both regions, up to t...

Geologic evidence of tropical sea level glaciation in the Neoproterozoic remains a matter of debate in the Snowball Earth hypothesis. The Niari Tillite Formation and the cap carbonates record the late Neoproterozoic Marinoan glaciation in South Gabon. These cap carbonates are located at the base of the Schisto-Calcaire Subgroup a predominantly carb...

The “Schisto-Calcaire Subgroup” is a muddy predominantly subtidal shelf succession that crops in the West Congolian Belt. The approximately 300-m-thick CI (Bas-Congo) and approximately 20-m-thick SCIII (Gabon) series were deposited in a very shallow marine evaporitic environment. The evidence for this interpretation includes sedimentology of dolomi...

Geologic evidence of tropical sea level glaciation in the Neoproterozoic remains a matter of debate in the Snowball Earth hypothesis. The Niari Tillite and the cap carbonates could record the late Neoproterozoic Marinoan glaciation in South Gabon. These cap carbonates (Sc1a Member) are located at the base of the Schisto-Calcaire Subgroup a predomin...

With the discovery in the 1970s of two-billion year old nuclear reactor in Oklo, Gabon, the Paleoproterozoic of the Franceville basin (Gabon), neglected for many years, attracted the attention of the international community. This led to the intensive study of the basin for about ten years. Between 2006 and the present time, our studies have focused...

The Neoproterozoic (630 Ma) Nsc3 or SCIII Formation (Schisto-Calcaire Subgroup) of the Nyanga Basin is a muddy peritidal carbonate (dolomite) shelf succession that is exposed in the old Mouila quarry (Kéri quarry), South Gabon. Its 20 m-thick lower member is dominated by microbially laminated dolomites and domal stromatolites representing shallow s...