scholarly journals Sedimentologic, Heavy Mineral and Provenance Studies of the Cretaceous Sediments in the Auchi Area of the Anambra Basin

2020 ◽  
Vol 24 (6) ◽  
pp. 955-959
Author(s):  
O.A. Ilegieuno ◽  
E.J. Ighodaro ◽  
R.O. Sunny
Keyword(s):  
Upper Cretaceous ◽  
Heavy Mineral ◽  
Coarse Grained ◽  
Metamorphic Rocks ◽  
Basement Complex ◽  
Provenance Studies ◽  
Anambra Basin ◽  
Edo State ◽  
Sand Particles ◽  
Cretaceous Deposits

The Upper Cretaceous Deposits of the Anambra Basin has a part of its sedimentary rock deposited in the Auchi area of Edo State. Geologic field and Sedimentological studies carried out on twenty eight (28) selected samples from a section of a road–cut show that the sediments range from fine through medium to coarse grained. Morphoscopic studies reveal subangular to subrounded outline of sand particles. These coupled with the  various colours observed in the sediment, ranging from whitish sand through yellowish brown, pink and reddish brown possibly indicate a non–marine environment and a fluviatile to deltaic environment of sedimentation is suggested. Heavy mineral assemblage made up mainly of opaque, andalusite, zircon, hornblend, sphene and epidote suggest derivation from the Precambrian Igneous and medium to high grade metamorphic rocks of the underlying Basement Complex of Nigeria. Keywords: Sedimentology, Cretaceous, Morphoscopic, Heavy Mineral, Provenance

scholarly journals Sedimentology and Paleogeographic Synthesis of Cretaceous Sediments in Auchi Area of Anambra Basin

2020 ◽  
Vol 24 (5) ◽  
pp. 943-974
Author(s):  
O.A. Ilegieuno ◽  
E.J. Ighodaro ◽  
R.O. Sunny
Keyword(s):  
Grain Size ◽  
Sedimentary Rock ◽  
Upper Cretaceous ◽  
High Energy ◽  
Coarse Grained ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Anambra Basin ◽  
Edo State ◽  
Cretaceous Deposits

The sedimentary rock in the Auchi area of Edo State constitutes part of the Upper Cretaceous Deposits of the Anambra Basin, which has its  depocentre in Eastern Nigeria. Lithostratigraphic and Sedimentological studies carried out on twenty eight (28) selected samples from a section of a road–cut show that the sediments range from fine through medium to coarse grained. Sorting is poor to moderate. Grain size analysis shows that the sediments are strongly fine skewed and they exhibit mesokurtic to platykurtic kurtosis. These coupled with the various colours observed in the sediment, ranging from whitish sand through yellowish brown, pink and reddish brown possibly indicate a non–marine environment and a fluviatile to deltaic environment of sedimentation is suggested. The sediments might have been transported in a fairly high energy medium and deposited under a slightly fluctuating velocity. Keywords: Sedimentology, Cretaceous, Paleogeography, Grain size, Anambra Basin

scholarly journals Heavy mineral studies of Gondwana sandstones of Eastern Arunachal Himalaya and implications for provenance

2017 ◽  
Vol 17 (1) ◽  
pp. 8-14 ◽  
Author(s):  
Bashab N. Mahanta ◽  
Ranjan K. Sarmah ◽  
Tapos Kumar Goswami ◽  
Banteilang R. Syngai
Keyword(s):  
Mineral Assemblage ◽  
Heavy Mineral ◽  
Metamorphic Rocks ◽  
Carbonaceous Shale ◽  
Arunachal Pradesh ◽  
Eastern Himalayas ◽  
Provenance Studies ◽  
Lower Gondwana ◽  
Siwalik Group ◽  
Arunachal Himalaya

A thin linear belt of Permian Lower Gondwana rocks occur in the Eastern Himalayas from Arunachal Pradesh to Sikkim. The Lower Gondwana Group of rocks consists of shale, siltstone, sandstone, carbonaceous shale and coaly matter and is sandwiched between Miri Group and Siwalik Group of rocks. Heavy mineral composition of sandstones is extensively used in the provenance studies as they are the surviving remnants of the rather abundant but unstable mafic components of the source rock. The sandstones of Lower Gondwana Group bear the heavy mineral assemblage of chlorite, biotite, zircon, ilmenite, epidote, garnet, amphibole, chloritoid, brown tourmaline, magnetite, staurolite, rutile, and opaques which is indicative of a provenance of metamorphic rocks with input of igneous rocks. Provenance sensitive mineral index ratios were also calculated to see the variation in the ratio of two or more stable minerals with the same characteristics.

scholarly journals Depositional Model, Pebble Provenance and Possible Reservoir Potential of Cretaceous Conglomerates: Example from the Southern Slope of Medvednica Mt. (Northern Croatia)

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 456 ◽  
Author(s):  
Jasenka Sremac ◽  
Josipa Velić ◽  
Marija Bošnjak ◽  
Ivo Velić ◽  
Davor Kudrnovski ◽  
...  
Keyword(s):  
Upper Cretaceous ◽  
Coarse Grained ◽  
Published Data ◽  
Southern Slope ◽  
Short Term ◽  
Third Order ◽  
Porosity And Permeability ◽  
Reservoir Potential ◽  
Northern Croatia ◽  
Cretaceous Deposits

Upper Cretaceous deposits in Medvednica Mt. are composed of coarse-grained conglomerates, sandstones, shales and the pelagic Scaglia Limestones. Such deposits in the wider region possess reservoir potential, not previously studied in Northern Croatia. Modal composition of conglomerates, size and distribution of clasts, porosity and permeability were studied from one new exposure in Medvednica Mt., and the results were compared with previously published data from neighboring successions. Conglomerates are polymictic, clast- to matrix-supported, with clasts and matrix entirely composed of local bedrocks. Porosity varies between 4.98 to 10.89% and permeability from 1.13 to 43.3 mD. Overlying pelagic Scaglia Limestones contain pelagic foraminifera of the latest Santonian to Early Campanian age (83 to 85 Ma). Clasts were eroded from the local hinterland, probably transported to the beach by short-term torrents and deposited along the shelves of the proto-Medvednica Island. Previously presumed alluvial transport is not likely. Deposition took place in a Gosau-type basin during the subsidence phase, additionally controlled by a third-order sea-level change at the Santonian-Campanian boundary. According to this study, Upper Cretaceous clastites possess possible reservoir potential, and deserve more attention in future hydrocarbon research in Croatia.

Diversity, morphology, and phylogeny of coleoid cephalopods from the Upper Cretaceous Plattenkalks of Lebanon-Part I: Prototeuthidina

2011 ◽  
Vol 85 (2) ◽  
pp. 234-249 ◽  
Author(s):  
Dirk Fuchs ◽  
Neal Larson
Keyword(s):  
Digestive Tract ◽  
Upper Cretaceous ◽  
Soft Part ◽  
Phylogenetic Analyses ◽  
Early Jurassic ◽  
The Other ◽  
Large Collection ◽  
Shaped Body ◽  
Cretaceous Deposits

Morphologic analyses of a large collection of coleoid cephalopods from the Lebanese Upper Cretaceous yielded a much higher diversity than previously assumed and revealed numerous extraordinarily well-preserved, soft-part characters. An analysis of the Prototeuthidina, a gladius-bearing group with a slender torpedo-shaped body, revealed two species:Dorateuthis syriacaandBoreopeltis smithin. sp. Previously unknown soft-part characters, such as the digestive tract, the gills, and the cephalic cartilage considerably improved our knowledge ofD. syriaca.Since none of the investigated specimens show more than eight arms, similarities with modern squids are regarded as superficial.Boreopeltis smithin. sp. is erected on the basis of its comparatively wideParaplesioteuthis-like gladius. The latter species represents the first unambiguous record of this genus in Upper Cretaceous deposits. Phylogenetic analyses indicate that the prototeuthidid clade consists of two lineages. The plesioteuthidid lineage originates from early JurassicParaplesioteuthisand leads toPlesioteuthisandDorateuthis.The other lineage is morphologically more conservative and leads toBoreopeltis.

scholarly journals Investigation of Geology and Hydro-geophysical Features Using Electromagnetic and Vertical Sounding Methods for Abu Zabad Area, Western Kordofan State, Sudan

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Ahmed Babeker Elhag
Keyword(s):  
Geophysical Methods ◽  
Structural Features ◽  
Groundwater Potential ◽  
Crystalline Basement ◽  
Metamorphic Rocks ◽  
Basement Rock ◽  
Basement Complex ◽  
Groundwater Aquifers ◽  
Electrical Sounding ◽  
Geophysical Features

The geology and hydro-geophysical features can aid in identifying borehole location. The study aims to investigate groundwater aquifers and best location of boreholes in the crystalline basement area of Abu Zabad near El Obeid Southwest, Sudan. The study area is underlain by two aquifers formations from Precambrian age. The oldest units of basement complex of area under investigation consist of metamorphic rocks including gneiss, schist, and quartzite.The geophysical methods electromagnetic (EM) and vertical electrical sounding (VES) surveys showed that best aquifers yield for construction of boreholes are in weathering and fractures formation. The EM results revealed that structural features are significant for groundwater potential and interpretation of the VES data also revealed four geo-electric layers, but generally two distinct lithologic layers, which include Superficial deposit and bedrock-basement respectively. The curves generated from the data revealed H curve and HK curve, and thickness of these layers varies from 15 m to 50 m in the area. The aquifer thickness range from 20 m to 30 m. The study concludes that these techniques are suitable for identifying borehole location in the basement rock in Abu Zabad Area Sudan.

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