Abstract Mineralogical, geochemical and the potentiality of source shale rocks in the Khabour Formation from the Akkas-1 well, western Iraq and the Chia Zinnar section exposed in extreme northern Iraq were studied. Whole rock minerals observed are quartz, feldspars (labradorite, albite and orthoclase), pyrite and rare calcite. The main clay minerals observed in the studied shales are illite, chlorite, kaolinite, and mixed layer illite. SEM analysis shows that kaolinite is typically present as hexagonal plates and booklets, some of which are degraded, illite is commonly present as fibers and fine white flakes. Mixed layer illite is commonly observed as framboidal shapes while chlorite is observed as disc-shaped chlorite. Two samples from the upper, Hirnantian, part of the Akkas-1 well exhibit great differences from post Archean Australian shale (PAAS) in both major and trace element geochemistry. This is in contrast to the 13 other samples from the Akkas-1 well which have a trace element composition very close to PAAS. These differences are hard to interpret but they may record the impact of the Hirnantian glaciation. Common redox indicators (Th/U, Cu/Zn, V/Rb, Mn) all suggest an oxic environmental conditions prevailed during deposition of the Khabour Formation in the Akkas-1 well; this is supported by low TOC values. Khabour shales from the Akkas-1 well are organically lean (TOC 0.04–0.84%) and are late to post mature for oil generation. They represent poor sedimentary organic matter (SOM) but the presence of bitumen in the samples suggest source rocks do exist in this part of the succession. The studied samples from the Chia Zinnar section (extreme northern Iraq) are organically lean (TOC

中文翻译：

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伊拉克Cambro-Ordovician Khabour组页岩的矿物学、地球化学和源潜力

摘要 对伊拉克西部Akkas-1井Khabour组和伊拉克极北地区出露的Chia Zinnar剖面的Khabour组页岩的矿物学、地球化学和潜力进行了研究。观察到的全岩矿物有石英、长石（拉长石、钠长石和正长石）、黄铁矿和稀有方解石。研究页岩中观察到的主要粘土矿物为伊利石、绿泥石、高岭石和混合层伊利石。SEM 分析表明，高岭石通常以六边形片状和小册子形式存在，其中一些已降解，伊利石通常以纤维和细白色薄片形式存在。混合层伊利石通常观察为框架状绿泥石，而绿泥石观察为圆盘状绿泥石。来自鞋面的两个样品，Hirnantian，Akkas-1 井的一部分在主要和微量元素地球化学方面与太古宙后澳大利亚页岩 (PAAS) 表现出很大差异。这与来自 Akkas-1 井的 13 个其他样品形成对比，这些样品的微量元素组成非常接近 PAAS。这些差异很难解释，但它们可能记录了 Hirnantian 冰川作用的影响。常见的氧化还原指示剂（Th/U、Cu/Zn、V/Rb、Mn）都表明在 Akkas-1 井中 Khabour 组沉积期间普遍存在含氧环境条件；这得到了低 TOC 值的支持。Akkas-1 井的 Khabour 页岩有机贫化（TOC 0.04-0.84%），后期成熟后生油。它们代表了较差的沉积有机质 (SOM)，但样品中沥青的存在表明在这部分序列中确实存在烃源岩。