Clay mineral variation in Tertiary sediments from the eastern flank of the Niger Delta

Clay Minerals ◽  
1986 ◽  
Vol 21 (2) ◽  
pp. 211-224 ◽  
Author(s):  
S. P. Braide ◽  
W. D. Huff
Keyword(s):  
Clay Mineral ◽  
Niger Delta ◽  
Size Fraction ◽  
Clay Mineralogy ◽  
Burial Diagenesis ◽  
Carbonate Cement ◽  
Eastern Flank ◽  
Marine Facies ◽  
Diagenetic Reactions ◽  
The Relationship

AbstractDetailed clay mineralogical and chemical analyses of well cuttings of Tertiary sediments from two wells, Uruan-1 and Uda-1, on the eastern flank of the Niger delta, have been made in an attempt to investigate clay mineral burial diagenesis. The clay mineralogy indicates a transformation of smectite to an interstratified illite-smectite (I/S) phase. The relationship between ordered and random interlayering, however, is nonsystematic. The chemistry of the <0·1 µm size fraction shows some tendency towards a net gain in K2O and Al2O3 and a net loss in SiO2 with depth, but the relationship does not correlate well with the thermal gradient. The distribution of kaolinite and chlorite in both wells appears to be unrelated in any regular way to smectite transformation and these two minerals are considered to be either the products of other diagenetic reactions affecting various stratigraphic levels, or the result of primary sediment deposition. In well Uda-1, kaolinite decreases in relative abundance with depth. This trend has been interpreted elsewhere as indicative of a transition from nonmarine to marine facies. The results of this study indicate that lack of ion mobility, rather than availability, is a significant factor in retarding the formation of ordered I/S with depth, and that lithology, overpressuring, carbonate cement, and original smectite layer charge may be controlling factors in the smectite → illite transformation.

Complex permittivity and clay mineralogy of grain-size fractions in a wet silt soil

Geophysics ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. J1-J13 ◽  
Author(s):  
Steven Arcone ◽  
Steven Grant ◽  
Ginger Boitnott ◽  
Benjamin Bostick
Keyword(s):  
Grain Size ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Complex Permittivity ◽  
Mineral Content ◽  
Size Fraction ◽  
Clay Mineralogy ◽  
Free Water ◽  
Size Fractions ◽  
Grain Size Fractions

We determined the complex permittivity and clay mineralogy of grain-size fractions in a wet silt soil. We used one clay-size fraction and three silt-size fractions, measured permittivity with low error from [Formula: see text] with time-domain spectroscopy, and estimated mineral weight percentages using X-ray diffraction (XRD). The volumetric water contents were near 30%, and the temperature was [Formula: see text]. For the whole soil, standard fractionation procedures yielded 2.4% clay-size particles by weight, but XRD showed that the phyllosilicate clay minerals kaolinite, illite, and smectite made up 17% and were significantly present in all fractions. Above approximately [Formula: see text], all real parts were similar. Below approximately [Formula: see text], the real and imaginary permittivities increased with decreasing grain size as frequency decreased, and the imaginary parts became dominated by direct-current conduction. Similarly, below approximately [Formula: see text], the measured permittivity of montmorillonite, a common smectite, dominated that of the other clay minerals. Total clay mineral and smectite mass fractions consistently increased with decreasing grain size. Below [Formula: see text], a model with progressively increasing amounts of water and parameters characteristic of montmorillonite matches the data well for all fractions, predicts permittivities characteristic of free water in smectite structural galleries, and shows that the similar real parts above [Formula: see text] are caused by a small suppression of the high-frequency static value of water permittivity by the smectite. We conclude that the clay mineral content, particularly smectite, appears to be responsible for permittivity variations between grain-size fractions. Small model mismatches in real permittivity near the low-frequency end and the greater fractions of kaolinite and illite suggest that the total clay mineral content might have been important for the coarser fractions.

Diagenetic chlorite formation in some Mesozoic shales from the Sleipner area of the North Sea

Clay Minerals ◽  
1985 ◽  
Vol 20 (1) ◽  
pp. 69-79 ◽  
Author(s):  
A. Hurst
Keyword(s):  
Clay Mineral ◽  
North Sea ◽  
Clay Mineralogy ◽  
Reliable Indicator ◽  
Burial Diagenesis ◽  
The North ◽  
The North Sea ◽  
Temperature Controlled ◽  
Mineral Transformations

AbstractDiagenetic chlorite is forming as a result of temperature-controlled burial diagenesis in shales from the Sleipner area of the North Sea. Accompanying chlorite diagenesis, kaolinite and illite-smectite decrease in abundance, and illite increases in abundance. These clay mineral transformations occur between 122–126°C at temperatures higher than normally expected for chlorite diagenesis. Kaolinite and ordered illite-smectite are largely unaffected by diagenesis below 100°C. It is proposed that chlorite diagenesis is thus delayed due to the absence of a source of ions resulting from smectite decomposition. Clay mineralogy is of no lithostratigraphic use in the Jurassic sediments of the Sleipner area. However, the zone of chlorite diagenesis is a reliable indicator of maximum burial temperature.

Clay mineralogy of onshore UK Carboniferous mudrocks

Clay Minerals ◽  
2006 ◽  
Vol 41 (1) ◽  
pp. 395-416 ◽  
Author(s):  
D. A. Spears
Keyword(s):  
Clay Mineral ◽  
Depositional Environment ◽  
Volcanic Ash ◽  
Clay Mineralogy ◽  
Source Rocks ◽  
Burial Diagenesis ◽  
Geographic Variations ◽  
Factors Affecting ◽  
Mineral Assemblages ◽  
Clay Rocks

AbstractThe Carboniferous in Britain is diverse and this is reflected in the clay mineral assemblages. Several factors affecting the assemblages are identified including climate, rates of weathering and erosion, source rocks in the hinterland, preservation of palaeosols, whether the source rocks are nearby or distant, sorting during transportation, the presence of altered volcanic ash-falls in the depositional environment and the extent of burial diagenesis. There are temporal and geographic variations in the clay mineral assemblages in the mudrocks as a result of these controls. There are also clay-rich rocks that differ from the normal mudrocks and a knowledge of the clay mineralogy of these is a necessary prerequisite to a full understanding of their origins. Mudrocks falling in this category, and described below, include bauxitic clays, flint clays, fragmental clay rocks, tonsteins and K-bentonites and various palaeosols.

scholarly journals The Jurassic of Skåne, southern Sweden

2003 ◽  
Vol 1 ◽  
pp. 527-541 ◽  
Author(s):  
Anders Ahlberg ◽  
Ulf Sivhed ◽  
Mikael Erlström
Keyword(s):  
Clay Mineralogy ◽  
Depositional Environments ◽  
Burial Diagenesis ◽  
Sea Level Changes ◽  
Humid Climate ◽  
Alluvial Deposits ◽  
Tectonic Zone ◽  
Marine Strata ◽  
Coal Beds ◽  
Shallow Marine Sediments

In Sweden, Jurassic strata are restricted to Skåne and adjacent offshore areas. Jurassic sedimentary rocks predominantly comprise sandy to muddy siliciclastics, with subordinate coal beds and few carbonate-rich beds. During Mesozoic times, block-faulting took place in the Sorgenfrei– Tornquist Zone, a tectonic zone which transects Skåne in a NW–SE direction. The Jurassic depositional environments in Skåne were thus strongly influenced by uplift and downfaulting, and to some extent by volcanism. Consequently, the sedimentary record reveals evidence of numerous transgressions, regressions and breaks in sedimentation. Relative sea-level changes played a significant role in controlling the facies distribution, as deposition mainly took place in coastal plain to shallow shelf environments. The alluvial deposits in Skåne include floodplain palaeosols, autochthonous coals, overbank sandstones, and stream channel pebbly sandstones. Restricted marine strata comprise intertidal heteroliths with mixed freshwater and marine trace fossil assemblages, and intertidal delta distributary channel sandstones. Shallow marine sediments encompass subtidal and shoreface sandstones with herringbone structures, and bioturbated mudstones with tempestite sandstones. Offshore deposits typically comprise extensively bioturbated muddy sandstones. Floral remains, palaeopedology, clay mineralogy and arenite maturity indicate a warm and humid climate in Skåne throughout the Jurassic, possibly with slightly increasing aridity towards the end of the period. Most Jurassic strata in Skåne have been subjected to mild burial diagenesis, and the petroleum generative window has rarely been reached.

Clay mineral-grain size-calcite cement relationships in the Upper Cretaceous Chalk, UK: a preliminary investigation

Clay Minerals ◽  
2014 ◽  
Vol 49 (2) ◽  
pp. 299-325 ◽  
Author(s):  
C. V. Jeans ◽  
N. J . Tosca ◽  
X. F. Hu ◽  
S. Boreham
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Trace Element ◽  
Size Distribution ◽  
Clay Mineral ◽  
Preliminary Investigation ◽  
Clay Mineralogy ◽  
Minor Amount ◽  
Dioctahedral Smectite ◽  
Calcite Cement

AbstractThe idea is tested that the evolution of the Chalk’s clay mineral assemblage during diagenesis can be deduced by examining the relationships between its clay mineralogy, particle size distribution pattern, and the timing and trace element chemistry of the calcite cement. The preliminary results from five different examples of cementation developed at different stages of diagenesis in chalks with smectite-dominated clay assemblages suggest that this is a promising line of investigation. Soft chalks with minor amount of anoxic series calcite cement poor in Mg, Fe and Mn are associated with neoformed trioctahedral smectite and/or dioctahedral nontronite and talc. Hard ground chalk with extensive anoxic series calcite cement enriched in Mg and relatively high Fe, Mn and Sr are associated with neoformed glauconite sensu lato, berthierine and dioctahedral smectite, possibly enriched in Fe. The chalk associated with large ammonites shows extensive suboxic series calcite cement enriched in Mg, Mn and Fe that show no obvious correlation with its clay mineralogy. Nodular chalks with patchy suboxic series calcite cement enriched in Fe are associated with neoformed dioctahedral smectite, possibly enriched in Al, and berthierine. Regionally hardened chalk with extensive suboxic calcite cement and relatively high trace element contents contain pressure dissolution seams enriched in kaolin and berthierine. Laser-based particle-size distribution patterns suggest that each type of lithification has a typical complex clay mineral population, indicating that subtleties in mineralogy are not being identified and that there could be some control on the size and shape of the clay crystals by the different types of cementation.

Applications of geochemistry and basin modeling in the diagenetic evaluation of Paleocene sandstones, Kupe Field, New Zealand

2021 ◽  
Vol 91 (9) ◽  
pp. 945-968
Author(s):  
Karen E. Higgs ◽  
Stuart Munday ◽  
Anne Forbes ◽  
Karsten F. Kroeger
Keyword(s):  
New Zealand ◽  
Element Abundance ◽  
Basin Modeling ◽  
Burial Diagenesis ◽  
Diagenetic Alteration ◽  
Partial Pressures ◽  
Diagenetic Reactions ◽  
Different Levels ◽  
Kupe Field ◽  
Thermal Decarboxylation

ABSTRACT Paleocene sandstones in the Kupe Field of Taranaki Basin, New Zealand, are subdivided into two diagenetic zones, an upper kaolinite–siderite (K-S) zone and a lower chlorite–smectite (Ch-Sm) zone. Petrographic observations show that the K-S zone has formed from diagenetic alteration of earlier-formed Ch-Sm sandstones, whereby biotite and chlorite–smectite have been altered to form kaolinite and siderite, and plagioclase has reacted to form kaolinite and quartz. These diagenetic zones can be difficult to discriminate from downhole bulk-rock geochemistry, which is largely due to a change in element-mineral affinities without a wholesale change in element abundance. However, some elements have proven useful for delimiting the diagenetic zones, particularly Ca and Na, where much lower abundances in the K-S zone are interpreted to represent removal of labile elements during diagenesis. Multivariate analysis has also proven an effective method of distinguishing the diagenetic zones by highlighting elemental affinities that are interpreted to represent the principal diagenetic phases. These include Fe-Mg-Mn (siderite) in the K-S zone, and Ca-Mn (calcite) and Fe-Mg-Ti-Y-Sc-V (biotite and chlorite–smectite) in the Ch-Sm zone. Results from this study demonstrate that the base of the K-S zone approximately corresponds to the base of the current hydrocarbon column. An assessment with 1D basin models and published stable-isotope data show that K-S diagenesis is likely to have occurred during deep-burial diagenesis in the last 4 Myr. Modeling predicts that CO2-rich fluids were generating from thermal decarboxylation of intraformational Paleocene coals at this time, and accumulation of high partial pressures of intraformational CO2 in the hydrocarbon column is considered a viable catalyst for the diagenetic reactions. Variable CO2 concentrations and residence times are interpreted to be the reason for different levels of K-S diagenesis, which is supported by a clear relationship between the presence or absence of a well-developed K-S zone and the present-day reservoir-corrected CO2 content.

scholarly journals Weeping in the Face of Fortune: Eco-Alienation in the Niger-Delta Ecopoetics

Humanities ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 54 ◽  
Author(s):  
Abba A. Abba ◽  
Nkiru D. Onyemachi
Keyword(s):  
Niger Delta ◽  
18Th Century ◽  
Human Beings ◽  
Delta Region ◽  
Niger Delta Region ◽  
Cultural Implications ◽  
The Face ◽  
Oil Wealth ◽  
The Relationship ◽  
The Universe

Scholarship on Niger Delta ecopoetry has concentrated on the economic, socio-political and cultural implications of eco-degradation in the oil-rich Niger Delta region of the South-South in Nigeria, but falls short of addressing the trope of eco-alienation, the sense of separation between people and nature, which seems to be a significant idea in Niger Delta ecopoetics. For sure, literary studies in particular and the Humanities at large have shown considerable interest in the concept of the Anthropocene and the resultant eco-alienation which has dominated contemporary global ecopoetics since the 18th century. In the age of the Anthropocene, human beings deploy their exceptional capabilities to alter nature and its essence, including the ecosystem, which invariably leads to eco-alienation, a sense of breach in the relationship between people and nature. For the Humanities, if this Anthropocentric positioning of humans has brought socio-economic advancement to humans, it has equally eroded human values. This paper thus attempts to show that the anthropocentric positioning of humans at the center of the universe, with its resultant hyper-capitalist greed, is the premise in the discussion of eco-alienation in Tanure Ojaide’s Delta Blues and Home Songs (1998) and Nnimmo Bassey’s We Thought It Was Oil but It Was Blood (2002). Arguing that both poetry collections articulate the feeling of disconnect between the inhabitants of the Niger Delta region and the oil wealth in their community, the paper strives to demonstrate that the Niger Delta indigenes, as a result, have been compelled to perceive the oil environment no longer as a source of improved life but as a metaphor for death. Relying on ecocritical discursive strategies, and seeking to further foreground the implication of the Anthropocene in the conception of eco-alienation, the paper demonstrates how poetry, as a humanistic discipline, lives up to its promise as a powerful medium for interrogating the trope of eco-estrangement both in contemporary Niger Delta ecopoetry and in global eco-discourse.

ECOLOGICAL AND TAPHONOMIC FIDELITY IN FOSSIL CRINOID ACCUMULATIONS

Palaios ◽  
2019 ◽  
Vol 34 (11) ◽  
pp. 575-583 ◽  
Author(s):  
DAVID L. MEYER ◽  
WILLIAM I. AUSICH
Keyword(s):  
Depositional Environments ◽  
Biological Processes ◽  
Post Mortem ◽  
Eastern Flank ◽  
South Central ◽  
Middle Mississippian ◽  
Symmetrical Distribution ◽  
Close Proximity ◽  
Marine Facies ◽  
Taphonomic Analysis

ABSTRACT Among fossiliferous marine facies, deposits rich in stalked echinoderms, particularly encrinites, have long been suspected to be susceptible to taphonomic biases because intact calyxes are under-represented or masked by disarticulated skeletal debris. In the middle Mississippian Fort Payne Formation of south-central Kentucky, penecontemporaneous crinoid-rich facies are exposed in close proximity along the shores of Lake Cumberland. Crinoidal packstone buildups preserve a broad preservational spectrum, with articulated crinoid calyxes with arms and columns attached, intact calyxes, holdfasts, and long articulated columns, in a matrix of entirely disarticulated crinoidal fragments. Along a 250 m transect across the flanks and crest of this buildup, identification of 563 specimens of crinoids and blastoids revealed a symmetrical distribution of taxa in which the crest was dominated by disparid and camerate crinoids and the flanks were dominated by camerates. Taphonomic analysis of the same transect showed that intact crinoid calyxes with or without attached arms and column occurred across the entire buildup, but nearly complete specimens with attached arms and column were most common on the western flank and less common on the crest and eastern flank. Taxonomic and taphonomic distributions demonstrate a primary ecologic zonation across the buildup with only localized post-mortem dispersal of crinoids. This is the first demonstration of primary ecologic zonation of a crinoid community preserved within a single lithofacies. Depending on depositional and taphonomic circumstances, crinoids are preserved intact close to their living site; understanding these physical and biological processes provides a significant feedback in reconstructing these ancient depositional environments.

Sign in / Sign up

Export Citation Format

Share Document