Browsing by Author "Kendie, Temesgen"

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    Paleomagnetic Investigation of Saha and Surrounding Area Volcanic Rocks, Central Afar, Northeast Ethiopia
    (Addis Ababa Universty, 2017-05) Kendie, Temesgen; Kidane, Tesfaye (PhD)
    The paleomagnetic investigation was located in the area of Saha and surrounding area, central Afar. The paleomagnetic samples were collected from nine lava flow unit outcrop of basalt (Gulf basalt) which exposed Saha and surrounding area (Central Afar). Five to nine samples were collected from each lava flow. The specimens conducted to partial demagnetize by using Alternating field (AF) and Thermal (TH) demagnetization techniques, as well as magnetize by Impulse magnetizer techniques (IM). The paleomagnetic results were measured by using JR- 6ASpinner Magnetometer from School of Earth Science paleomanetic laboratory in Addis Ababa University. The Natural Remenant magnetization (NRM) direction explains the specimens which display components of magnetizations were low stability component (secondary NRM) was removed by AF about 10mT- 30mT, by heating about 120°C- 300°C were as high stability components (primary NRM or characteristic remenant magnetization) above these steps and the vector straight line is directed towards the origin from orthogonal vector diagrams. The results of magnetization curve plots for magnetic rock analysis shows that magnetic mineralogy dominated by Ti- poor titanomagnetite, magnetite and few presence of maghemite. Principal component analysis and site mean direction calculated from both normal and reverse polarities. An overall mean direction was calculated from 9 individual site mean, the result obtained: D= 352.5°, I= 12.5°, K= 13.2, α95=14.7°, N= 9 and comparison with expected Geomagnetic Axial Dipole based on Apparent Polar Wander Path curve for 1Ma Mile- Gewane Ali Sabieh, (Kidane et al.,2003), as stable Africa plate Besse and Courtillot (2002). The mean paleomagnetic pole was calculated from the combined individual VGP, λ= 80.9°., ф =277.8°. , K = 22.8, α95 =11°. The declination difference which explains rotation of blocks about vertical axis was: =-7.2 ±6.6; difference in inclination was: = 3.9±3.2 obtained. This declination difference explains counter clock wise rotation about vertical axis due to the young propagation rift.