Lithological and alteration mapping using Landsat 8 and ASTER satellite data in the Reguibat Shield (West African Craton), North of Mauritania: implications for uranium exploration

2021 ◽  
Vol 14 (23) ◽  
Author(s):  
Mariem Mohameden Ishagh ◽  
Amin Beiranvand Pour ◽  
Hanafi Benali ◽  
Abdallahi Mohamedou Idriss ◽  
Sid’Ahmed Sidi Reyoug ◽  
...  
Author(s):  
Muhammad Danish Siddiqui ◽  
Arjumand Z Zaidi

<span>Seaweed is a marine plant or algae which has economic value in many parts of the world. The purpose of <span>this study is to evaluate different satellite sensors such as high-resolution WorldView-2 (WV2) satellite <span>data and Landsat 8 30-meter resolution satellite data for mapping seaweed resources along the coastal<br /><span>waters of Karachi. The continuous monitoring and mapping of this precious marine plant and their <span>breeding sites may not be very efficient and cost effective using traditional survey techniques. Remote <span>Sensing (RS) and Geographical Information System (GIS) can provide economical and more efficient <span>solutions for mapping and monitoring coastal resources quantitatively as well as qualitatively at both <span>temporal and spatial scales. Normalized Difference Vegetation Indices (NDVI) along with the image <span>enhancement techniques were used to delineate seaweed patches in the study area. The coverage area of <span>seaweed estimated with WV-2 and Landsat 8 are presented as GIS maps. A more precise area estimation <span>wasachieved with WV-2 data that shows 15.5Ha (0.155 Km<span>2<span>)of seaweed cover along Karachi coast that is <span>more representative of the field observed data. A much larger area wasestimated with Landsat 8 image <span>(71.28Ha or 0.7128 Km<span>2<span>) that was mainly due to the mixing of seaweed pixels with water pixels. The <span>WV-2 data, due to its better spatial resolution than Landsat 8, have proven to be more useful than Landsat<br /><span>8 in mapping seaweed patches</span></span></span></span></span></span></span></span></span></span></span></span></span></span><br /><br class="Apple-interchange-newline" /></span></span></span></span></span>


2008 ◽  
Vol 297 (1) ◽  
pp. 329-343 ◽  
Author(s):  
H. Ezzouhairi ◽  
M. L. Ribeiro ◽  
N. Ait Ayad ◽  
M. E. Moreira ◽  
A. Charif ◽  
...  

2021 ◽  
Author(s):  
Paul Yves Jean Antonio ◽  
Lenka Baratoux ◽  
Ricardo Ivan Ferreira Trindade ◽  
Sonia Rousse ◽  
Anani Ayite ◽  
...  

&lt;p&gt;The West African Craton (WAC) is one of the major cratons in the Rodinia jigsaw puzzle (~1000&amp;#8211;750 Ma). In the Rodinian models, the position of West Africa is mainly constrained by the assumption that it had been a partner of Amazonia since the Paleoproterozoic. Unfortunately, no paleomagnetic data are available for these cratons when the Rodina supercontinent is considered tectonically stable (~1000-750 Ma). Thus, every new reliable paleomagnetic pole for the West African Craton during the Neoproterozoic times is of paramount importance to constrain its position and testing the Rodinia models. In this study we present a combined paleomagnetic and geochronological investigation for the Manso dyke swarm in the Leo-Man Shield, southern West Africa (Ghana). The ~860 Ma emplacement age for the NNW-trending Manso dykes is thus well-constrained by two new U-Pb apatite ages of 857.2 &amp;#177; 8.5 Ma and 855 &amp;#177; 16 Ma, in agreement with baddeleyite data. Remanence of these coarse-to-fine grained dolerite dykes is carried by stable single to pseudo-single domain (SD-PSD) magnetite. A positive baked-contact test, associated to a positive reversal test (Class-C), support the primary remanence obtained for these dykes (13 sites). Moreover, our new paleomagnetic dataset satisfy all the seven R-criteria (R=7). The ~860 Ma Manso pole can thus be considered as the first key Tonian paleomagnetic pole for West Africa. We propose that the West Africa-Baltica-Amazonia-Congo-S&amp;#227;o Francisco were associated in a long-lived WABAMGO juxtaposition (~1100&amp;#8211;800 Ma).&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords:&lt;/strong&gt; West Africa, Neoproterozoic, Tonian, Rodinia, paleomagnetism.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;


2014 ◽  
Vol 255 ◽  
pp. 433-442 ◽  
Author(s):  
J. Javier Álvaro ◽  
André Pouclet ◽  
Hassan Ezzouhairi ◽  
Abderrahmane Soulaimani ◽  
El Hafid Bouougri ◽  
...  

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