Research Article
Petrographic and Geochemical Study of the Yandingui-Yangba Massif (Bafia, Central Cameroon): Geodynamic Implications
Issue:
Volume 14, Issue 3, June 2025
Pages:
93-104
Received:
30 March 2025
Accepted:
15 April 2025
Published:
9 May 2025
DOI:
10.11648/j.earth.20251403.11
Downloads:
Views:
Abstract: Several diverse models and hypotheses have been proposed to understand the dynamics of the Central African Pan-African Belt. The lack of agreement among these proposals suggests that it would be better to continue large scale mapping to provide answers to this regional issue. In this perspective, the NE-SW oriented Yandingui-Yangba rock massif, located about thirty kilometers north of Bafia, and intrudes a Precambrian metamorphic basement. The petrographic study of the massif reveals two lithological units: the metamorphic unit, which includes orthogneiss and amphibolite enclaves, and the intrusive magmatic unit, composed of amphibole-biotite granites. Geochemically, the rocks of Yandingui-Yangba (67.85 < SiO2 < 71.06) are metaluminous I-type granites (A/CNK < 1.1), associated with the shoshonitic series and of magnesian nature (0.67 < FeOt/(MgO + FeOt) < 0.78). Mantle-normalized trace element spectra show a subparallel pattern between the granites and orthogneiss, indicating a common origin. These rocks were emplaced in a volcanic arc setting in a subduction-collision context. The presence of positive anomalies in U, K, Pb, and Zr, and negative anomalies in Th, Nb, and Ti, is characteristic of crustal-derived rocks. The magma that generated these granites resulted from the partial melting of metagreywackes in the lower crust, as evidenced by the low concentrations of Ni and Cr. This melting was likely facilitated by heat influx from mantle-derived magma during the Pan-African orogeny.
Abstract: Several diverse models and hypotheses have been proposed to understand the dynamics of the Central African Pan-African Belt. The lack of agreement among these proposals suggests that it would be better to continue large scale mapping to provide answers to this regional issue. In this perspective, the NE-SW oriented Yandingui-Yangba rock massif, loc...
Show More
Research Article
Petroleum Reserves Formed in Noah’s Flood and Its Aftermath: A Proposed Geological Model
Harry Dickens*
Issue:
Volume 14, Issue 3, June 2025
Pages:
105-115
Received:
17 May 2025
Accepted:
3 June 2025
Published:
23 June 2025
DOI:
10.11648/j.earth.20251403.12
Downloads:
Views:
Abstract: The historical stage-by-stage settings (both scriptural and stratigraphic) for petroleum reserves have received little attention in the Creationist literature. The challenge is how to correlate the Bible’s stages with the history of petroleum reserves inferred from the geological record. Trends in the geology of oil and gas reserves through time can be recognized. These trends were correlated consistently and successively with time stages evident from Scripture. A historical framework for oil and natural gas reserves is proposed in association with Noah’s Flood and its aftermath. A biblical young earth history stage model is proposed including topographic destruction, marine transgression, receding waters, and widespread drying, followed by seafloor spreading and associated continental mountain-building. These are inferred to respectively correlate with Neoproterozoic, Early Paleozoic, Late Paleozoic, Triassic, and Jurassic to Tertiary strata and their contained petroleum reserves. Seafloor spreading and associated continental mountain-building in a new Flood model are inferred to have occurred shortly after the Flood Year itself, but triggered by receding Flood waters. Matters considered in this paper include erosion and marine platforms, tectonic and basin style changes, different types of organic matter source material for petroleum, pre-Flood and post-Flood coal, marine and non-marine deposition, along with global sea level rise and fall, and drying.
Abstract: The historical stage-by-stage settings (both scriptural and stratigraphic) for petroleum reserves have received little attention in the Creationist literature. The challenge is how to correlate the Bible’s stages with the history of petroleum reserves inferred from the geological record. Trends in the geology of oil and gas reserves through time ca...
Show More
Research Article
Variation of Faunal Diversity Across Paleogene-Neogene Boundary Along Selected Transects, Kutch Basin, Gujarat, Western India
Ujan Karmakar*
Issue:
Volume 14, Issue 3, June 2025
Pages:
116-128
Received:
8 March 2025
Accepted:
21 March 2025
Published:
25 June 2025
DOI:
10.11648/j.earth.20251403.13
Downloads:
Views:
Abstract: The Kutch Basin, of Gujarat, western India, is host to a diverse species of vertebrates and invertebrate faunas, which are both marine and terrestrial in origin. Kutch due its passive continental setting, has experienced multiple transgressive and regressive events on its carbonate platform, and was favourable for the growth and preservation of various living organisms in the Cenozoic. These organisms are mainly foraminifera, molluscs, bivalves, corals, echinoids, oyesters and vertebrates. Here in this work, we discuss, and compare the paleoecosystems of Paleogene with respect to the Neogene, of the Kutch Basin, and discuss how the ecosystem of Paleogene of the Kutch basin changes towards the Neogene. We have also tried to understand the genesis of the Middle Eocene Archaeocete fossil. In the Eocene, we have found large amounts of LBFs, such as Assilina, N. obtusus, Nummulites; mega-invertebrates; and vertebrate fossils such as (Remingtonocetus harudiensis, a middle Eocene Cetacea). In Oligocene formations, the dominant faunas are, Corals, echinoids such as Clypeasteroids and gastropods such as Physa, and very less diversity of LBFs, such as Operculina, Lepidocyclina and Spiroclypeus. The Miocene period is associated with newer taxa of microfossils such as Miogypsina, Ammonia sp, fossilized tree roots and land vertebrates of Gomphotherium indet and Brachypotherium sp. It is concluded, that the Paleogene was dominated by primitive vertebrates, in an isolated tropical forest ecosystem, and the marine faunas resided in shallow marine shelf or reef ecosystem, within a basic environment. Whereas the Neogene, was attributed by newer faunas, which migrated from North Africa and Afro-Arabia, as well as the Tibetan landmass, and resided in cooler drier, forest ecosystems and marsh environment, and the marine vertebrates resided in shallow creek environments and were resistant to terrigenous influx, and acidic environment. We hypothesized that the species of Paleogene of Kutch, morphologically and functionally habituated with a primitive ecosystem and endemic to the Indian sub-continent, whereas the species of Neogene are newer and complex and ancestors to the present day extant species.
Abstract: The Kutch Basin, of Gujarat, western India, is host to a diverse species of vertebrates and invertebrate faunas, which are both marine and terrestrial in origin. Kutch due its passive continental setting, has experienced multiple transgressive and regressive events on its carbonate platform, and was favourable for the growth and preservation of var...
Show More
