Paleomagnetic Investigation Of Saha And Surrounding Area Volcanic Rocks Central Afar Northeast Ethiopia

The paleomagnetic investigation was located in the area of Saha and surrounding area, centralrnAfar. The paleomagnetic samples were collected from nine lava flow unit outcrop of basalt (Gulfrnbasalt) which exposed Saha and surrounding area (Central Afar). Five to nine samples wererncollected from each lava flow. The specimens conducted to partial demagnetize by usingrnAlternating field (AF) and Thermal (TH) demagnetization techniques, as well as magnetize byrnImpulse magnetizer techniques (IM). The paleomagnetic results were measured by using JR-rn6ASpinner Magnetometer from School of Earth Science paleomanetic laboratory in Addis AbabarnUniversity. The Natural Remenant magnetization (NRM) direction explains the specimens whichrndisplay components of magnetizations were low stability component (secondary NRM) wasrnremoved by AF about 10mT- 30mT, by heating about 120°C- 300°C were as high stabilityrncomponents (primary NRM or characteristic remenant magnetization) above these steps and thernvector straight line is directed towards the origin from orthogonal vector diagrams. The results ofrnmagnetization curve plots for magnetic rock analysis shows that magnetic mineralogy dominatedrnby Ti- poor titanomagnetite, magnetite and few presence of maghemite. Principal componentrnanalysis and site mean direction calculated from both normal and reverse polarities. An overallrnmean direction was calculated from 9 individual site mean, the result obtained: D= 352.5°, I=rn12.5°, K= 13.2, α95=14.7°, N= 9 and comparison with expected Geomagnetic Axial Dipolernbased on Apparent Polar Wander Path curve for 1Ma Mile- Gewane Ali Sabieh, (Kidane etrnal.,2003), as stable Africa plate Besse and Courtillot (2002). The mean paleomagnetic pole wasrncalculated from the combined individual VGP, λ= 80.9°., ф =277.8°. , K = 22.8, α95 =11°. Therndeclination difference which explains rotation of blocks about vertical axis was: =-7.2 ±6.6;rndifference in inclination was: = 3.9±3.2 obtained. This declination difference explains counterrnclock wise rotation about vertical axis due to the young propagation rift.

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