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首页> 外文会议>Asian conference on remote sensing;ACRS 2008 >MAPPING NEOPROTEROZOIC STRUCTURES ALONG THE CENTRAL ALLAQI-HEIANI SUTURE, SOUTHEASTERN EGYPT, USING REMOTE SENSING AND FIELD DATA
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MAPPING NEOPROTEROZOIC STRUCTURES ALONG THE CENTRAL ALLAQI-HEIANI SUTURE, SOUTHEASTERN EGYPT, USING REMOTE SENSING AND FIELD DATA

机译：利用遥感和野外数据绘制东南埃及中部阿拉基－黑亚尼缝合线的新元古代构造

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The Allaqi-Heiani suture in southeastern Egypt represents the western part of the main Allaqi-Heiani-Onib-Sol Hamed-Yanbu suture that is exposed in Egypt, Sudan and Saudi Arabia as one of the Neoproterozoic ophiolite-decorated, arc-arc sutures in the Arabian-Nubian Shield (ANS). The Egyptian part of the suture extends for ca. 250 km from the north-trending Hamisana shear zone in the east to the Nile River in the west. It separates the ca. 750 Ma south Eastern Desert terrane in the north from the ca. 830-720 Ma Gabgaba terrane in the south. The suture zone is defined by a deformational belt made up of ophiolitic gabbros, serpentinites and mafic volcanics, which are imbricated with syn-tectonic granitoids and metasediments. The whole rock suite is intruded by post-tectonic granitoids and gabbros. The suture zone suffered a poly-phase structural deformation that led to a complex structural pattern.For precise lithological mapping and delineation of geological structures along the suture zone, we utilized digital image processing techniques to enhance Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data to produce high quality images suitable for photogeological interpretation. These techniques included false color band composition (7, 4, 1 in R, G, B), principal component analysis (PC1, PC2, PC3 in R, G, B) and band-ratios (5/7, 5/1, 5/4~*3/4 in R, G, B and 5/7, 7/5, 5/4~*3/4 in R, G, B). Density slicing of the implemented four band ratios (5/7, 7/5, 5/1 and 5/4~*3/4) has been used to produce a photogeological map. The mapped rock units were checked in the field and the attitudes of both planer and linear structures were measured and subsequently analyzed for better understanding of the structural setting of the central Allaqi-Heiani suture zone. The serpentinites and related ophiolitic rocks were followed along strike to identify the structural continuity and changes in strike direction.Photogeological interpretation and field studies indicate that the central part of the Allaqi-Heiani suture zone is dominated by WNW-ESE striking low angle thrusts that are associated with asymmetrical folds whose axial planes are parallel to these thrusts. Folds are verging towards SSW. Additionally, a series of NNW-SSE oriented parallel folds are dominated in the eastern part.Structural analysis indicates that the central part of the Allaqi-Heiani suture zone has undergone a poly-phase structural deformation involving, at least, two phases. Each phase has its own structural style and stress regime. The first phase (D1) was associated with an overall N-S or NNE-SSW shortening that produced SSW-verging folds and thrusts. The second phase (D2) was associated with an overall ENE-WSW shortening, which produced NNW-SSE oriented folds in the central and eastern parts of the study area and reactivated the older thrusts with oblique-slip reverse fault movement.
机译：埃及东南部的Allaqi-Heiani缝合线代表了主要的Allaqi-Heiani-Onib-Sol Hamed-Yanbu缝合线的西部，该缝合线在埃及，苏丹和沙特阿拉伯暴露，是新元古代蛇绿岩装饰的弧形缝合线之一阿拉伯-努比亚盾（ANS）。缝线的埃及部分延伸约。从东部的北部趋势Hamisana剪切带到西部的尼罗河250公里。它将ca分开。大约在750 Ma东南沙漠地带，位于加利福尼亚北部。南部的830-720 Ma Gabgaba地形。缝线区是由一条变形带定义的，该变形带由滑石长辉岩，蛇纹岩和镁铁质火山岩组成，并与同构造的类花岗岩和变质沉积物交织在一起。整个岩石套件都被后构造花岗岩和辉长岩侵入。缝线区经历了多相结构变形，从而导致了复杂的结构图案。 为了沿缝线区域精确地进行岩性制图和地质结构的划分，我们利用数字图像处理技术来增强Landsat 7 Enhanced Thematic Mapper Plus（ETM +）数据，以生成适用于光地质解释的高质量图像。这些技术包括假色带成分（R，G，B中的7、4、1），主成分分析（R，G，B中的PC1，PC2，PC3）和谱带比率（5 / 7、5 / 1， R，G，B中的5/4〜* 3/4和R，G，B中的5 / 7、7 / 5、5 / 4〜* 3/4）。已实现的四个波段比率（5 / 7、7 / 5、5 / 1和5/4〜* 3/4）的密度切片已用于生成光地质图。在野外检查了测绘的岩石单元，测量了平面结构和线性结构的姿态，随后进行了分析，以更好地了解阿拉基奇－安阿尼（Alianqi-Heiani）缝合中心带的结构环境。沿走向跟踪蛇纹岩和相关的蛇纹岩，以识别结构的连续性和走向的变化。 光地质学解释和野外研究表明，阿拉克-黑亚尼缝合带的中部主要由WNW-ESE打击低角度冲断力所主导，这些冲力与不对称褶皱有关，其轴向平面平行于这些冲力。褶皱正在向SSW迈进。此外，东部地区以NNW-SSE定向的一系列平行褶皱为主。 结构分析表明，Allaqi-Heiani缝合带的中心部分经历了多相结构变形，涉及至少两个阶段。每个阶段都有其自己的结构样式和应力状态。第一阶段（D1）与整个N-S或NNE-SSW缩短有关，该缩短产生了SSW趋向的褶皱和逆冲作用。第二阶段（D2）与整个ENE-WSW缩短有关，该缩短在研究区域的中部和东部产生了NNW-SSE定向的褶皱，并通过斜滑反向断裂运动重新激活了较早的逆冲作用。

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