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标题：Magnetization of three Nubia Sandstone formations from Central Western Desert of Egypt
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作者：H. El-Shayeb ; I.A. El-Hemaly ; E. Abdel Aal 等
期刊名称：NRIAG Journal of Astronomy and Geophysics
印刷版ISSN：2090-9977
电子版ISSN：2090-9985
出版年度：2013
卷号：2
期号：1
页码：77-87
DOI：10.1016/j.nrjag.2013.06.011
语种：English
出版社：Elsevier
摘要：AbstractA total of 198 oriented cores (from 16 sites) have been sampled from three Cretaceous Nubia sandstone formations distributed around the Kharga–Dakhla and Dakhla–Uwainat roads in the Western Desert for paleomagnetic studies. Two of these formations are of the Early Cretaceous (the Six Hills, Abu Ballas formations) and the third one is of the Late Cretaceous (Maghrabi formation). The studied rocks are subjected to rock magnetic measurements as well as demagnetization treatment.Rock magnetic experiments reveal that the presence of hematite is the main magnetic mineral in the three formations. Therefore, present study relies mostly on thermal demagnetization.Two magnetic components have been isolated from the studied rocks. The first component has been isolated from the Six Hills and Abu Ballas formations and is carried by hematite withD=347.1°,I=41.6° withα95=7.8° and the corresponding pole lies at lat.=78.2° N and long.=294.1° E. The second component has been isolated from the Maghrabi formation and is carried also by hematite withD=22.7°,I=28.4° withα95=9.9° and pole position lies at lat.=66.3° N and long.=140.6° E.The first magnetic component obtained from the two older formations is considered primary, as the corresponding pole reflects the age when compared with the previously obtained Cretaceous poles for North Africa. On other hand, the second pole obtained from the Maghrabi formation (the younger) is inconsistent with the Cretaceous pole positions for North Africa, but falls closer to the Eocene pole indicating that the rocks of this formation could have suffered remagnetization during the late Eocene time.