The Central Eastern Desert (CED) is a key territory for understanding the evolution of the Arabian Nubian Shield (ANS) in Egypt as it contains Cryogenian-Tonian ensimatic supracrustal assemblages, such as ophiolitic and arc volcanic rocks, as well as gold deposits. So, it has been the subject of extensive studies over the last two decades. However, the lithological mapping of the Fawakhir-Atalla belt, located west of the Meatiq gneiss dome (infrastructure) of the CED, is still debated, as the magmatic texture of some rocks was partially obscured owing to the shearing and alteration related to the Najd Fault System, mantle CO-bearing fluid, and igneous activity in the final stage of the Pan-African Orogeny. In this regard, integrated studies of airborne gamma-ray spectrometry and Landsat-9 satellite imagery processing techniques, as well as field and petrographic investigations, have been used for the lithological mapping of the belt. The results led to the following sequence; ophiolitic rocks > island arc assemblages > older granitoids (syn-tectonic subduction-related) > Hammamat Group (molasse-type origin) > post-Hammamat felsite > younger granite (post-tectonic suture-related). The applied color composite images, selective band ratios, and image transformation techniques show a clear distinction between rock units. Older granitoids are tonalite to quartz diorite, while younger granites are monzo-to syenogranite. They are well-discriminated from each other using band ratios, and younger granites have the highest K, eU, and eTh values coherent with the post-Hammamat felsite. The image enhancement and image transformation techniques show a clear discrepancy between the mélange rocks and Hammamat conglomerates. Mélange rocks are composed of fragments embedded in a foliated matrix, while Hammamat conglomerates are grain-supported with pebbles of volcanic source and have higher K, eU, and eTh values. Volcanic rocks in the belt are not a part of the Dokhan series as they are metamorphosed with a composition range from meta-basalts to meta-rhyolite, and show mainly aphanitic to infrequently porphyritic textures, which are typical of island arc metavolcanics.

中文翻译：

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基于 Landsat-9 遥感数据、机载伽马射线光谱测量、野外和岩相研究对埃及中东部沙漠 Fawakhir-Atalla 带的岩性判别对阿拉伯努比亚地盾演化的影响

中东沙漠（CED）是了解埃及阿拉伯努比亚地盾（ANS）演化的关键区域，因为它包含成冰期-托尼期的表壳组合，例如蛇绿岩和弧火山岩，以及金矿床。因此，在过去的二十年里，它一直是广泛研究的主题。然而，位于 CED 的 Meatiq 片麻岩穹顶（基础设施）以西的 Fawakhir-Atalla 带的岩性测绘仍然存在争议，因为一些岩石的岩浆结构由于与内志相关的剪切和蚀变而部分模糊。泛非造山运动末期的断层系统、地幔含二氧化碳流体和火成岩活动。在这方面，机载伽马射线能谱测量和 Landsat-9 卫星图像处理技术的综合研究以及现场和岩相调查已被用于该带的岩性测绘。结果导致以下顺序：蛇绿岩 > 岛弧组合 > 较古老的花岗岩（与同构造俯冲有关） > 哈马马特群（磨拉石型成因） > 后哈马马特长英岩 > 较年轻的花岗岩（与后构造缝合线有关）。应用的彩色合成图像、选择性波段比和图像变换技术显示出岩石单元之间的明显区别。较老的花岗岩是英闪长岩到石英闪长岩，而较年轻的花岗岩是二长花岗岩到正长花岗岩。使用能带比可以很好地区分它们，年轻的花岗岩具有与哈马马特之后的霏细岩一致的最高 K、eU 和 eTh 值。图像增强和图像转换技术显示混杂岩和哈马马特砾岩之间存在明显差异。混杂岩由嵌入片状基质中的碎片组成，而哈马马特砾岩由火山源卵石支撑，具有较高的 K、eU 和 eTh 值。该带中的火山岩不属于 Dokhan 系列，因为它们的变质作用范围从变玄武岩到变流纹岩，并且主要显示隐晶质到罕见的斑状结构，这是典型的岛弧变火山岩。