Stratigraphy and depositional environments of the Mamfe Formation and its implication on the tectonosedimentary evolution of the Ikom-Mamfe Embayment, West Africa

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Clement Bassey ◽  
Oboho Eminue ◽  
Humphrey Ajonina
Keyword(s):  
Depositional Environment ◽  
Source Area ◽  
Climatic Conditions ◽  
Depositional Environments ◽  
Coarse Grained ◽  
Ocean Water ◽  
Benue Trough ◽  
Base Level ◽  
Structural Differences ◽  
Lower Benue Trough

AbstractA 42 m thick outcropping portion of the Mamfe Formation is subdivided into Manyu (31 m thick) and Kesham (11m thick) Members on the basis of textural, mineralogical and structural differences. The Manyu Member (Albian) consists of folded and indurated, medium to coarse grained arkosic sandstones and thickly laminated organic-rich shales deposited in a lacustrine environment. The Kesham Member (Cenomanian) consists of subarkoses intercalated with massive green shale and mudstone deposited in a fluvial environment. The change in depositional environment was tectonically controlled. The mid Cretaceous paleogeography of the embayment was governed by the NE-SW trending “Ikom ridge” which prevented marine incursion from adjacent the Benue Sea. Evaporites found within the basin were precipitated from ocean water that was periodically spilled by strong tides and storms across the ridge into the embayment. The filling-up of the embayment to base level in the Cenomanian resulted in a shift in the depositional center downstream to adjoining lower Benue Trough. Similarity in heavy mineral composition and maturity of the Cenomanian sandstones with recent clastics in the embayment indicates their derivation from the same source terrain and relatively stable tectonic and climatic conditions at the source area since the Cenomanian time.

Cenomanian to Coniacian sea-level changes in the Lower Benue Trough (Nkalagu Area, Nigeria) and the Eastern Dahomey Basin: palaeontological and sedimentological evidence for eustasy and tectonism

2019 ◽  
Vol 498 (1) ◽  
pp. 233-255 ◽  
Author(s):  
Holger Gebhardt ◽  
Samuel O. Akande ◽  
Olabisi A. Adekeye
Keyword(s):  
Sea Level ◽  
Deep Water ◽  
Close Relation ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Foraminiferal Assemblage ◽  
Benue Trough ◽  
Sea Level Fluctuations ◽  
Dahomey Basin ◽  
Lower Benue Trough

AbstractThe Benue Trough formed in close relation to the opening of the South Atlantic and experienced sea-level fluctuations of different magnitudes during the Cenomanian to Coniacian interval. We identify depositional environments from outcrop sections and a drilling as control record. Lines of evidence for the interpretation include facies analyses, foraminiferal assemblage composition (P/B-ratio) and the presence of planktonic deep-water indicators. While the analysis of the well data from the Dahomey Basin indicates a continuous deep-water (bathyal) environment, the succession in the Nkalagu area of the Lower Benue Trough evolved in a different and more complex way. Beginning with latest Cenomanian shoreface to shelf deposits, a long period of subsidence lasted until the middle Turonian when pelagic shales and calcareous turbidites were deposited at upper to middle bathyal depths. These conditions continued during late Turonian and Coniacian times. The general deepening trend of the Lower Benue Trough was mainly controlled by tectonic subsidence and was superimposed by eustatic sea-level changes, resulting in periodically changing palaeowater depths. We were able to identify eight sea-level rises and falls that can be attributed to 405 kyr eccentricity cycles. The amplitudes of the sea-level changes were most likely in the range of several tens to a few hundred metres. The deposition of carbonate turbidites at Nkalagu was probably triggered by eustatic sea-level lowstands.

scholarly journals Braided-river and hyperconcentrated-flow deposits from the Carboniferous of the Lublin Basin (SE Poland) – a sedimentological study of core data

Geologos ◽  
2012 ◽  
Vol 18 (3) ◽  
pp. 135-161 ◽  
Author(s):  
Maria I. Waksmundzka
Keyword(s):  
Source Area ◽  
High Energy ◽  
Coarse Grained ◽  
Type I ◽  
Braided River ◽  
River Channels ◽  
Fine Grained ◽  
Braided Rivers ◽  
Base Level ◽  
Se Poland

Abstract Fining-upwards cyclothems found in five boreholes in the Carboniferous (Lower Bashkirian) of the Lublin Basin were analysed sedimentologically. It was established that the cyclothems represent fluvial deposits, and the lithofacies were grouped into lithofacies associations. Most lithofacies associations represent three types of sand-bed braided rivers: (1) high-energy, (2) deep and (3) distal sheetflood-affected. Other associations represent hyperconcentrated flows. Both coarse-grained (type I) and fine-grained (types IIa and IIb) occur among the fining-upward cyclothems. The formation of most thick cyclothems was related mainly to allocyclic factors, i.e. a decrease in the river’s gradient. The thickest fining-upward cyclothems are characteristic of hyperconcentrated flows and braided-river channels. The aggradation ratios were commonly high. During the early Namurian C and early Westphalian A (Early Bashkirian), the eastern part of the Lublin Basin was located close to the source area. The sedimentary succession developed due to a transition from high-energy braidedrivers and hyperconcentrated flows to lower-energy braided rivers, controlled by a rise of the regional base level.

Provenance, tectonics and palaeo environment of Mesoproterozoic Saundatti Quartzite Member of Kaladgi Basin, India: A petrographic view.

2020 ◽  
Vol 37 (2) ◽  
pp. 91-102
Author(s):  
Purushottam Anil Verlekar ◽  
Mahender Kotha
Keyword(s):  
Source Area ◽  
Sedimentary Basins ◽  
Depositional Environments ◽  
Coarse Grained ◽  
Variable Degree ◽  
Carbonate Sediments ◽  
Peninsular India ◽  
Textural Parameters ◽  
Different Sources ◽  
Basin Margin

The Kaladgi Basin, one of the important Proterozoic Sedimentary basins of Peninsular India, exposes a thick sequence of Proterozoic succession composed of a variety of lithologies with predominance of arenaceous rocks interrupted with Carbonate sediments at different stratigraphic levels. The present work focuses mainly on understanding the Sedimentological nature and diagenetic character of the Lower part of the Lokapur sub-group rocks that are exposed in and around Savadatti Town, Belagavi District of Karnataka. These rocks are mainly composed of Arenite sequences of varying grain size. The clastic succession comprises lithologies Sandstones with minor conglomeratic facies at the lower regimes. An attempt is made to identify the detailed petrographic character of the sandstones to understand the provenance and depositional environments based on the detailed petrographic observation. The study suggests that the coarse clastic conglomerates are essentially polymictic types and the sandstones are sub-mature to mature (mineralogically), medium to coarse grained and can be categorized mainly into lithic/feldspathic and quartz arenites. Minor occurance of feldspars as the framework constituent also suggests that the rock have undergone considerable transport. However with their variable degree of alteration (from fresh to partially alter to completely altered grains) associated with textural maturity and nature of Quartz point towards the possibility of derivation of these sediments from two different sources. Palaeocurrent data that indicate a NW palaeoslope suggest the derivation of sediments from a variety of granitic and gnesssic crystalline complexes occurring along the basin margin. The maturity of the sandstones (Quartz Arenites) is attributed to the recycling and re-working of the older sediments. Analysis of Textural parameters of these rocks pointed towards deposition under beach environments. The lack in preservation of much amount of feldspar in these sandstones is indicates a remote source and relatively dry-arid climate of the source area.

scholarly journals DELTAIC AND SHELF DEPOSITIONAL PACKAGES OF THE GULANI MEMBER OF PINDIGA FORMATION, GONGOLA SUB-BASIN, NORTHERN BENUE TROUGH, N.E. NIGERIA

2018 ◽  
Vol 6 (4) ◽  
pp. 188-197
Author(s):  
B. Shettima ◽  
A.I. Goro ◽  
M. Bukar ◽  
Y.B. Mohammed
Keyword(s):  
Depositional Environment ◽  
Facies Analysis ◽  
Coarse Grained ◽  
Delta Front ◽  
Benue Trough ◽  
Fine Grained

Stratigraphic and facies analysis of the Gulani Member of the Pindiga Formation in the Gongola Sub-basin of the Northern Benue Trough indicated that the lithostratigraphic architecture of the formation are characterized by three bioturbated lithologic units. These includes the lower succession of heterolithic units with fine grained sandstones and mudstone interbeds, passing into succession of medium-coarse grained sandstone with dominantly trough crossbeds and a upper succession of medium grained trough crossbedded sandstone and mudstone interbeds. Facies evaluation of these distinct succession indicated development of a corresponding pro-delta sands and clays, moving into delta front sands and then shelf sandstone and claystone respectively. Thus suggesting that the Gulani Member was generally formed in a coastal setting defined by river dominated deltaic setting and shelf depositional environment.

scholarly journals Grain Size Analysis, Textural Characterisation and Depositional Environment of Turonian Amasiri Sandstone, Southern Benue Trough, Nigeria

2021 ◽  
Vol 4 (2) ◽  
Keyword(s):  
Grain Size ◽  
Depositional Environment ◽  
Function Analysis ◽  
High Energy ◽  
Coarse Grained ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Benue Trough ◽  
Shallow Marine ◽  
Wide Range

Grain size analysis of Turonian Amasiri Sandstone in southern Benue Trough has been undertaken to determine the controversial depositional environment of the formation. The formation was first studied on outcrops and 26 representative samples were collected and subjected to particle size analysis in line with standard procedures for dry sieving. Various methods of environmental interpretation of grain size distribution data were applied to constrain the depositional of the sandstones. The result indicates that the sands are medium and coarse-grained with mean size ranging from 0.15 to 1.87φ and averaging 0.96 φ. The sandstones are moderately to poorly sorted with standard deviation values ranging from 0.72 to 1.38 φ and averaging 1.07 φ. They exhibit a wide range of distribution from strongly coarse skewed to strongly fine skewed with skewness values ranging from -2.31 to 1.52 φ and averaging -0.04 φ but indicate a narrow range of kurtosis from mesokurtic to leptokurtic distribution with values ranging from 0.99 to 3.49 φ and an average of 2.06 φ. The sediments have bimodal with minor polymodal and unimodal distribution with primary modal size of 1.2 φ. The bivariate plots of size statistical parameters indicate fluvial environment of deposition. However, linear discriminant function analysis and the interpretations of log-probability plots indicate deposition in a fluvial, beach, and shallow marine settings, and thus suggesting a possible deposition in high-energy transitional environment. The C-M pattern of the samples indicates that sediments were transported mainly by rolling and suspension with subordinate fractions moved by rolling as well as suspension. Thus, it is deduced that Amasiri Sandstone was deposited in fluvial, beach, and agitated shallow marine environments.

Provenance and depositional characteristics of Lathi Formation in southern part of Jaisalmer Basin: Implications for exploration of sandstone type uranium mineralization

2021 ◽  
Vol 38 (1) ◽  
pp. 41-50
Author(s):  
Shijo Mathew ◽  
Pritam Karmakar ◽  
Rajeev Bidwai ◽  
S K Sharma ◽  
Navin Goyal ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Gravity Data ◽  
Source Area ◽  
Sedimentary Facies ◽  
Climatic Conditions ◽  
Uranium Mineralization ◽  
Coarse Grained ◽  
Geochemical Data ◽  
Carbonaceous Matter ◽  
Jaisalmer Basin

The lower Jurassic Lathi Formation covers about 900 sq. km area and forms the lowermost unit of Jaisalmer Basin of western Rajasthan. Lithologically the Lathi Formation comprises of conglomerate, sandstone, siltstone, shale and mudstone. The sandstones are generally medium- to coarse-grained, moderately sorted and show variation in colour, grain-size and texture. Petrographic studies indicate a mixed provenance for the Lathi sandstone. On the basis of geochemical data, theses sandstones are classified into sub-arkose, litharenite and sub-litharenite. Palaeo-weathering indices such as CIA (80.45), CIW (85.23) and PIA (84.23) suggest moderate to high degree of chemical weathering of the source area, intermediate and felsic igneous provenance, under humid to semi-humid climatic conditions. Further, the geochemical data indicate the sedimentation in a passive continental margin setting. The Bouguer gravity image clearly depicts the north westward slope of the basement. Modelling studies of the gravity data revealed average depth to the basement as 800m, 400m and 250m respectively in northwest, central and southeastern parts of the surveyed area. Exploration activities by Atomic Minerals Directorate for Exploration and Research have resulted in location of several uranium anomalies in the Lathi Formation. Lathi Formation is characterised by many favourable parameters such as fertile provenance, arkosic sandstones intercalated with shale/mudstone, reduced sedimentary facies with carbonaceous matter, lignite and pyrite deposited in continental to marginal marine environment. Malani Igneous Suit and metamorphic rocks constitute the basement for Jaisalmer Basin. Malani rhyolites and granites are fertile source of uranium, containing 6.7 ppm and 9.2 ppm average and intrinsic uranium respectively. Presence of carbonaceous matter and pyrite bearing sandstones, indicative of reducing environment at depth below water table (R.L. 150 m), was reported during subsurface exploration in Lathi sandstone which is a favourable condition for Lathi sediments to host uranium mineralization.

scholarly journals Paleo-Environmental Conditions, Paleoclimatic Significance and Effects of Weathering on Clay Deposits in the Lower Benue Trough, Nigeria. Mineralogical Approach

2019 ◽  
Vol 1 (2) ◽  
Author(s):  
A. T. Bolarinwa ◽  
Sunday Ojochogwu Idakwo ◽  
D. L. Bish
Keyword(s):  
Environmental Conditions ◽  
Chemical Weathering ◽  
Bulk Sample ◽  
Climatic Conditions ◽  
Source Rocks ◽  
Benue Trough ◽  
Clay Deposits ◽  
Parent Rocks ◽  
Lower Benue Trough ◽  
Paleoclimatic Significance

Combined methods for mineralogical identifications were used to characterise the clay deposits within the Lower Benue Trough of Nigeria to interpret paleo-environmental conditions, the paleoclimatic significance of the trough, and effects of weathering on the minerals as factors that favour its deposition/accumulation within the trough which host other important industrial minerals like coal, barite, limestone etc. Bulk-sample random-powder XRD data and data for clay fractions deposited onto zero-background quartz plates were measured. The samples contained kaolinite, vermiculite, and traces of smectite, and the non-clay phases included quartz, microcline, and muscovite. All samples were unaffected after glycolation, confirming the absence of significant smectite. Muscovite was characterized by the nature of its 10 Å basal peak with a width of <0.10° 2θ, which was very sharp. DTA/TGA results support the presence of kaolinite, and the characteristic kaolinite O-H, Al-OH, Si-OH and Si-O-Al FTIR bands also confirmed its presence. Vermicular and book-like morphologies were observed under the SEM, typical of kaolinitic clay from in situ alteration. High kaolinite abundance in these sediments is consistent with intense weathering of parent rocks rich in Al under wet/tropical paleo-climatic conditions with fresh and/or brackish water conditions in a continental setting. The variety of observed morphologies suggests that the deposits suffered more of chemical weathering. The clay deposits in Lower Benue Trough are quartz-rich, kaolinitic and derived from the chemical weathering of Al-rich source rocks.

scholarly journals STUDIUM SPODNOBADENSKÝCH BAZÁLNÍCH KLASTIK V OBLASTI PODZEMNÍHO ZÁSOBNÍKU PLYNU LOBODICE

2014 ◽  
Vol 21 (1-2) ◽  
Author(s):  
David Blaško ◽  
Slavomír Nehyba ◽  
Anita Bartakovics
Keyword(s):  
Depositional Environment ◽  
Sedimentary Rocks ◽  
Outer Part ◽  
Source Area ◽  
Crystalline Rocks ◽  
Source Material ◽  
Coarse Grained ◽  
Source Areas ◽  
Traction Current ◽  
Analysis Point

The depositional environment and the provenance of the Lower Badenian basal clastics in the area of Lobodice subsurface gas storage were described during the studies of these sediments.Drill cores of Lobodice wells were studied in the total length of 110 m for the purpose of depositional environment evaluation. The textures and structures were described on these cores and on this basis three lithofacies were recognized. The lithofacies A is represented by grey matrix supported, granule conglomerate, very poorly sorted. This lithofaces has been interpreted as the product of deposition of a coarse grained delta. The lithofacies B is formed by fine and medium sandstone with ripple cross lamination, very well sorted sandstone. This facies was interpreted as the result of a relatively low energy of traction current, probably deposited in marine environment. The lithofacies C is formed by greyish clay siltstone, locally with planar lamination and common bioturbation. The lithofacies C was interpreted as the product of deposition in the off shore condition (outer part of the shelf?).The results of pebble analysis and analysis of the chemistry of garnets and rutiles were used for the evaluation of the source areas of the Lower Badenian basal clastics.Pebble analysis shows that the studied Lower Badenian clastics are polymict. Grey limestones dominate in the pebble spectra and also oft en represent the largest clasts. Light-coloured limestones, shales and graywackes (most probably Culmian), quartzes and dolomites are relatively common. The content of pebbles of crystalline rocks is relative low. These results indicate the prevalence of sedimentary rocks in the source area and/or recycling of the source material. This results together with garnet and rutile analysis point to the source from the Culmian rock of Drahanská Vrchovina Upland and Nízký Jeseník Highland (especially the rocks of the Myslejovice Formation) and also probably from the Carpathian Flysch Belt.

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