Palynostratigraphy, palynofacies and palaeoenvironment of deposition of Selandian to Aquitanian sediments, southeastern Nigeria

Okeke, K.K.; Umeji, Obianuju P.

doi:10.1016/j.jafrearsci.2016.04.020

Cited by 21 publications

(13 citation statements)

References 20 publications

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“…It is faced with the challenges of providing a growing population with food, water, shelter, sanity and basic amenities [32,33]. Urbanization has created rapid growth of housing/industrial estates, proliferation of ghettos, slums, and shanty areas to accommodate the increased population, and has necessitated anthropogenic activities which consequently altered the LULC [34]. Natural forests and grasslands are being converted to arable lands, commercial centers and residential areas.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, many plant species and their associated ecosystem services have been lost. During the last two decades in the study area, 0.2-0.4 hectares of land was lost annually to soil erosion due to high rate of deforestation while, more than 3% of the total vegetation cover was replaced by either settlement, sand deposits or floodplain [34]. The government, the agriculturists and the urban planners have increased the number of housing units and facilities development, established more commercial towns, and expanded arable lands to satisfy the growing population.…”

Section: Introductionmentioning

confidence: 99%

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Is Nigeria losing its natural vegetation and landscape? Assessing the landuse-landcover change trajectories and effects in Onitsha using remote sensing and GIS

Nwaogu

Okeke²,

Fadipe

et al. 2017

Open Geosciences

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Onitsha is one of the largest commercial cities in Africa with its population growth rate increasing arithmetically for the past two decades. This situation has direct and indirect effects on the natural resources including vegetation and water. The study aimed at assessing land use-land cover (LULC) change and its effects on the vegetation and landscape from 1987 to 2015 using geoinformatics. Supervised and unsupervised classifications including maximum likelihood algorithm were performed using ENVI 4.7 and ArcGIS 10.1 versions. The LULC was classified into 7 classes: built-up areas (settlement), waterbody, thick vegetation, light vegetation, riparian vegetation, sand deposit (bare soil) and floodplain. The result revealed that all the three vegetation types decreased in areas throughout the study period while, settlement, sand deposit and floodplain areas have remarkable increase of about 100% in 2015 when compared with the total in 1987. Number of dominant plant species decreased continuously during the study. The overall classification accuracies in 1987, 2002 and 2015 was 90.7%, 92.9% and 95.5% respectively. The overall kappa coefficient of the image classification for 1987, 2002 and 2015 was 0.98, 0.93 and 0.96 respectively. In general, the average classification was above 90%, a proof that the classification was reliable and acceptable.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Is Nigeria losing its natural vegetation and landscape? Assessing the landuse-landcover change trajectories and effects in Onitsha using remote sensing and GIS

Nwaogu

Okeke²,

Fadipe

et al. 2017

Open Geosciences

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show abstract

“…This valuable tool has been used in palaeoenvironmental, palaeoclimatological and palaeoceanographic reconstructions (e.g. van der Zwan 1990, Tyson 1995, Batten 1996, Gastaldo et al 1998, Cirilli et al 2015, Hochuli et al 2015, García Muro et al 2016, Kumar et al 2016, Okeke & Umeji 2016, Koch et al 2017) and has recently been tested in characterization of Holocene alluvial and palustrine deposits (e.g. Gastaldo & Huc 1992, Laggoun-Défarge et al 1995, Cohen et al 1999, Di Giovanni et al 1999, Bourdon et al 2000, Sebag et al 2006a, b, Serna et al 2015 through the identification and quantification of organic matter (OM) phytoclasts according to their origin, nature, formation or preservation in sedimentary processes.…”

mentioning

confidence: 99%

Past environments of Sardinian archaeological sites (Italy, West Mediterranean Sea), based on palynofacies characterization

Pittau

Buosi

Scanu

2018

Acta Palaeobotanica

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A study method based on characterization of palynofacies (organic matter, palynomorphs) preserved in sediments was applied to obtain information about past environments of Sardinian sites. Organic matter (OM) was classified in ten categories according to its biological source, ecological characteristics, morphology and preservation state. These categories included woody and non-woody particles (cuticles, amorphous organic matter), phytoclasts, spores and pollen grains, gelified particles, and altered phytoclasts that ranged from transparent to opaque fragments. Cluster analysis classified the samples into associations. Each cluster includes stations with a similar spatial distribution pattern. The characterization of the different types of OM was coupled with palyno-logical analyses to produce suggested hypotheses about past vegetation, human activity and land use in Sardinia.

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“…and Cleistophaeridium sp. are indicative of slightly saline condition and near shore environment (Stover et al 1999, Okeke & Umeji 2016. The above assemblages suggest that the sediments of these intervals were deposited within a marine environment.…”

Section: Paleoenvironment Of Depositionmentioning

confidence: 95%

“…4) have zero palynomorph marine index values which suggest a fresh water environment. Chukwuma-Orji J.N., Okosun E.A., Ekom J.C., Abolarin J.F. These intervals consist of moderate records of pollen and spores with diagnostic marker species such as: Monocolpites marginatus, Longapertites marginatus, Echitriporites trianguliformis, Retidiporites magdalenensis, and Cyathidites minor, also suggest a brackish to fresh water environment (Okeke & Umeji 2016).…”

Section: Paleoenvironment Of Depositionmentioning

confidence: 98%

A palynology and paleoenvironmental study of a section from the Amansiodo-1 well, Anambra Basin, southeastern Nigeria

Chukwuma-Orji

Okosun²,

Ekom³

et al. 2017

geol

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Palynological analysis was carried out on twenty (20) ditch cutting samples from a section (1284.73-1496.57 m) of the Amansiodo-1 well, Anambra Basin, southeastern Nigeria with the aim of determining the age, biozone, and depositional environment of the sediments within the depth interval. The laboratory techniques of digesting sediments in hydrochloric and hydrofluoric acids for silicates and carbonates removal were followed to process the samples for the recovery of palynomorphs. Fifty two (52) palynomorph specimens were recovered. An assemblage zone of Echitriporites trianguliformis Zone has been established. The section was dated to the upper Maastrichtian due to the occurrences of age diagnostic marker species such as: Cingulatisporites ornatus, Distaverrusporites simplex, Proteacidites sigalii, Dinogymnium cf auclaense, Echitriporites trianguliformis and Retidiporites magdalensis. Based on the palynomorph marine index and environmental indicator flora, the section was inferred to be deposited in marine to brackish (coastal) environments with little influence of fresh water.

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Palynostratigraphy, palynofacies and palaeoenvironment of deposition of Selandian to Aquitanian sediments, southeastern Nigeria

Cited by 21 publications

References 20 publications

Is Nigeria losing its natural vegetation and landscape? Assessing the landuse-landcover change trajectories and effects in Onitsha using remote sensing and GIS

Is Nigeria losing its natural vegetation and landscape? Assessing the landuse-landcover change trajectories and effects in Onitsha using remote sensing and GIS

Past environments of Sardinian archaeological sites (Italy, West Mediterranean Sea), based on palynofacies characterization

A palynology and paleoenvironmental study of a section from the Amansiodo-1 well, Anambra Basin, southeastern Nigeria

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