Multivariate Statistical Analyses of Palynodebris from the Middle Miocene of the Niger Delta and Their Environmental Significance

Oboh, Francisca E.

doi:10.2307/3514869

Cited by 29 publications

(11 citation statements)

References 2 publications

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“…The general assumptions of palynofacies studies of passive margins (e.g., Oboh, 1992;Habib et al, 1994) indicate that a high concentration of terrestrially derived organic matter suggests proximity to the paleoshoreline, while a high concentration of marine-derived AOM is indicative of a distal location. In a transform margin setting, this assumption may not hold true in all cases because of tectonic processes.…”

Section: Palynofacies Analysismentioning

confidence: 99%

Palynostratigraphy, palynofacies, and thermal maturation of CretaceousPaleocene sediments from the Côte d'Ivoire-Ghana Transform Margin

Oboh‐Ikuenobe¹,

Yepes²,

Gregg³

1998

Proceedings of the Ocean Drilling Program, 159 Scientific Results

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Cretaceous to Paleocene sediments from Ocean Drilling Program Sites 959 to 962 in the Côte d'Ivoire-Ghana Transform Margin yield a rich assemblage of dinoflagellate cysts, few acritarchs, spores and pollen, and 12 types of dispersed organic matter. Dinoflagellate cysts proved invaluable in the refinement of shipboard-generated age determinations for Turonian to Paleocene sediments and identification of the Cretaceous/Paleocene boundary at Site 959. A few spore and pollen taxa are of stratigraphic significance. All but two samples of the tectonized basal siliciclastic sediments are barren of dinoflagellate cysts at Sites 959 and 960, but a few samples yield a very low diversity assemblage of spores and pollen. Palynofacies analysis indicates that amorphous organic matter is the dominant organic component in the sediments. However, the tectonized siliciclastic sedments are richer in identifiable terrestrially derived components (wood, black debris, and cuticles) or amorphous organic matter of terrestrial origin. Samples immediately below post-Albian unconformity surfaces at Sites 959 to 961 are enriched in wood and black debris. Thermal alteration indices (TAI) were derived from semiquantitative assessment of spore and pollen colors and used to interpret the thermal maturation of the sediments. TAI values indicate (1) a mature to overmature stage (values >2.5, occasionally dark) for the tectonized basal siliciclastic sediments at all four sites; (2) a moderately mature stage (2− 2.5) for some Upper Cretaceous sediments at Sites 959, 960, and 962; and (3) an immature stage (<2) for the rest of the stratigraphic section. The most mature sediments were deposited during the syntransform phase of basin evolution. 1 Mascle, J., Lohmann, G.P., and Moullade, M. (Eds.), 1998. Proc. ODP, Sci. Results, 159: College Station, TX (Ocean Drilling Program).

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Section: Palynofacies Analysismentioning

confidence: 99%

Palynostratigraphy, palynofacies, and thermal maturation of CretaceousPaleocene sediments from the Côte d'Ivoire-Ghana Transform Margin

Oboh‐Ikuenobe¹,

Yepes²,

Gregg³

1998

Proceedings of the Ocean Drilling Program, 159 Scientific Results

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“…8), the opaque to semi-opaque fraction becomes predominant as a result of gravity separation and oxic biodegradation of the delicate translucent fraction (cf. Fisher, 1980;Parry et al, 1981;Oboh, 1992;Blonde1 et al, 1993;Tyson, 1995).…”

Section: Phytoclastsmentioning

confidence: 99%

Distribution of sedimentary organic matter in a mixed carbonate‐siliciclastic platform environment: Oxfordian of the Swiss Jura Mountains

Pittet

Gorin

1997

Sedimentology

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Outcrop sections from the Swiss Jura, consisting of carbonate‐siliciclastic deposits spanning the Middle‐Late Oxfordian boundary, provide a palaeogeographical cross‐section ranging from coastal to shallow platform and intra‐platform basin environments. Using a sedimentological and a 3rd order sequence stratigraphic framework based on those sections, the distribution of sedimentary organic matter (palynofacies) has been spatially studied in relation to sequence stratigraphy. The main factors influencing the spatial variations of sedimentary organic matter are the proximity of land, organic productivity, level of biodegradation and hydrodynamic conditions of the palaeoenvironment. These factors determine the distribution of the land‐derived, relatively allochthonous organic constituents (phytoclasts, pollen and spores), and marine, relatively autochthonous constituents (phytoplankton and foraminifera linings). Five main palynofacies parameters appear as good indicators of proximal‐distal trends: the relative proportion of total phytoclasts; the proportion of fresh, translucent fragments among these phytoclasts; the ratio of marine to continental palynomorphs; and the relative amount and species diversity of dinoflagellate cysts. In lowstand deposits, high‐energy hydrodynamic conditions may affect these trends on the shallow platform, where storms tend to increase the proportion of the marine organic fraction landwards. These five palynofacies parameters are largely related to water depth. Therefore, when compared with the established 3rd order sequence stratigraphic framework, their stratigraphic variations indicate relative sea‐level changes or, alternatively, proximality changes. Parameters indicative of more distal conditions increase in the transgressive and early highstand, and decrease in the late highstand. The opposite occurs for parameters indicative of more proximal conditions. Foraminifera linings seem to be particularly concentrated near the shelf edge and on the slope. Finally, bisaccate pollen may display cyclicity associated with alternating humid and dry periods. This palaeoclimatic signature may be related to orbital cyclicity.

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“…Because of this, charcoal-like kerogen tends to be abundant in sandstones, and less so in shales (e.g. Oboh-Ikuenobe, 1992). 'Charcoal analysis' in older sediments, that may have been subject to diagenesis and early katagenesis, may therefore give misleading results.…”

Section: Laboratory Methodsmentioning

confidence: 99%

Palaeoenvironmental setting of MojokertoHomo erectus, the palynological expressions of Pleistocene marine deltas, open grasslands and volcanic mountains in East Java

Morley

Morley²,

Zaim

et al. 2020

Journal of Biogeography

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Aim To determine the vegetation and landscape experienced by Homo erectus populations which first inhabited Java. Location Perning, near Mojokerto, East Java, the 1936 discovery locality of a fossil child's skull widely attributed to H. erectus, and laterally equivalent sediments at Jetis. Taxon Terrestrial, mangrove and aquatic plants. Methods A comprehensive suite of samples was collected at close spacing through a coastal sedimentary succession analysed concurrently for its depositional origins. The section traversed particularly informative marine, delta front and delta plain deposits, including the bonebed in which the H. erectus was discovered. Results Rich palynomorph recovery indicative of mangroves was obtained in the mud‐dominated marine Mollusk Member II at the base of the analysed section. The overlying deltaic strata are characterized by grass pollen and phytoliths, while still retaining mangrove and wetland signals in key samples near the level of the H. erectus bed. Main conclusion The vertical stratigraphic series of facies in the Perning and adjacent Jetis sections indicates a landscape with four potential Homo habitats: muddy deltas with widespread Nypa swamps; a poorly vegetated sandy delta; extensive open savanna grasslands in the lowlands up river of the delta; and volcanoes in the upper reaches of the catchment with perhumid montane podocarp and broad‐leaf forests and probable open fire‐climax Casuarina junghuhniana forest. Palynological data support an Early Pleistocene geological age for Mojokerto H. erectus at about 1.43 Myr.

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Multivariate Statistical Analyses of Palynodebris from the Middle Miocene of the Niger Delta and Their Environmental Significance

Cited by 29 publications

References 2 publications

Palynostratigraphy, palynofacies, and thermal maturation of CretaceousPaleocene sediments from the Côte d'Ivoire-Ghana Transform Margin

Palynostratigraphy, palynofacies, and thermal maturation of CretaceousPaleocene sediments from the Côte d'Ivoire-Ghana Transform Margin

Distribution of sedimentary organic matter in a mixed carbonate‐siliciclastic platform environment: Oxfordian of the Swiss Jura Mountains

Palaeoenvironmental setting of MojokertoHomo erectus, the palynological expressions of Pleistocene marine deltas, open grasslands and volcanic mountains in East Java

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Multivariate Statistical Analyses of Palynodebris from the Middle Miocene of the Niger Delta and Their Environmental Significance

Cited by 29 publications

References 2 publications

Palynostratigraphy, palynofacies, and thermal maturation of CretaceousPaleocene sediments from the Côte d'Ivoire-Ghana Transform Margin

Palynostratigraphy, palynofacies, and thermal maturation of CretaceousPaleocene sediments from the Côte d'Ivoire-Ghana Transform Margin

Distribution of sedimentary organic matter in a mixed carbonate‐siliciclastic platform environment: Oxfordian of the Swiss Jura Mountains

Palaeoenvironmental setting of MojokertoHomo erectus, the palynological expressions of Pleistocene marine deltas, open grasslands and volcanic mountains in East Java

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Palynostratigraphy, palynofacies, and thermal maturation of CretaceousPaleocene sediments from the Côte d'Ivoire-Ghana Transform Margin

Palynostratigraphy, palynofacies, and thermal maturation of CretaceousPaleocene sediments from the Côte d'Ivoire-Ghana Transform Margin