scholarly journals Depositional environment of the Gombe Formation in the Gongola sub-basin of the northern Benue trough: Using grain size parameters

2017 ◽  
Vol 15 (1) ◽  
pp. 25
Author(s):  
M.B. Usman ◽  
Y.D. Mamman ◽  
U. Abubakar ◽  
A. Sulaiman ◽  
H. Hamidu
Keyword(s):  
Grain Size ◽  
Depositional Environment ◽  
Benue Trough ◽  
Grain Size Parameters

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.

Grain-size parameters of marine sediments

Oceanology ◽  
2006 ◽  
Vol 46 (3) ◽  
pp. 430-439
Author(s):  
T. N. Alekseeva ◽  
V. N. Sval’nov
Keyword(s):  
Grain Size ◽  
Marine Sediments ◽  
Grain Size Parameters

scholarly journals Actuopaleontological investigations of shallow water Red Sea echinoids

1992 ◽  
Vol 6 ◽  
pp. 220-220
Author(s):  
James H. Nebelsick
Keyword(s):  
Grain Size ◽  
Red Sea ◽  
Distribution Patterns ◽  
Close Correlation ◽  
Time Averaging ◽  
Multivariate Statistical ◽  
Cryptic Habitats ◽  
Echinometra Mathaei ◽  
Grain Size Parameters ◽  
Diadema Setosum

The regular and irregular echinoid fauna of the Northern Bay of Safaga (Red Sea, Egypt) has been investigated within the framework of an actuopaleontological study of the flora, fauna, sediments and facies. The distribution of echinoids has been compared to grain size parameters as well as to the distribution of other organisms.The study area (ca. 10 × 7 km) was investigated using SCUBA-diving techniques along 55 transects with a total length of 126 km. Echinoid presence was quantified using weights of fragments (2 mm) originating from 67 standardized bulk samples distributed throughout the Bay. The complex morphology of the echinoid test and the spines allow the identification of fragmented material upon comparison to complete specimens. The resulting data was analyzed using correlation techniques as well as Q and R-mode multivariate statistical analysis. This method counters the difficulties originating from the cryptic habitats and patchy distributions.The results of the analysis show that echinoid distribution can be analyzed for both regular and irregular wchinoid taxa despite taphonomic bias and restrictions imposed by the analytic method. Time averaging in fact counters the difficulties arising from the patchy distributions of echinoids. There is a close correlation of echinoid distribution to sedimentary and bottom facies as well as to grain size parameters and other environmental factors. The distribution of irregular echinoids is highly differentiated with coarse coastal sand dominated by Clypeaster sp., Echinodiscus auritus, Fibularia ovulum, and Lovenia elongata; muddy sands by Laganum depressum, Clypeaster sp. and Echinocyamus crispus; and muds by members of the Schizasteridae. Regular echinoids, mostly Eucidaris metularia, Echinometra mathaei, Tripneustes gratilla, Heterocentrotus mammillatus and Diadema setosum, dominate the sediments found within, or near reefs, coral carpets and patch reefs.The methodology used in this actuopaleontological investigation should be useful in recognizing the distribution patterns of ancient echinoid faunas, especially in light of the significance of regular echinoids in the bioerosion of reefs and irregular echinoids in the bioturbation of sediments.

Grain Size Analysis for Elucidation of Depositional Environment of Kalpakkam, India

2018 ◽  
Vol 5 (1) ◽  
pp. 183-199
Author(s):  
K. Deepthi ◽  
Usha Natesan ◽  
A. L. Muthulakshmi ◽  
Vincent A. Ferrer ◽  
S. V. Narasimhan ◽  
...  
Keyword(s):  
Grain Size ◽  
Depositional Environment ◽  
Grain Size Analysis ◽  
Size Analysis
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