Generation and reorganization of Oman oceanic crust-mantle

1. 在阿曼北部蛇绿岩上地幔剖面中，我们认识到橄榄岩的岩石学变化、变形历史、矿物的晶体学变化和糜棱岩的起源。还发现了高pge铬铁矿。根据岩石学特征，将晚侵入岩分为三种类型。马马长岩挤出物与苦橄岩玄武岩（晚期侵入岩的一个淬灭阶段）有关。根据辉长岩层的构造变化估计了洋中脊的分割构造。北长辉长岩侵入段中心附近的衍生岩浆室，对周围片状脉杂岩形成接触变质作用，达到麻粒岩相。厘清了岩浆库顶带的构造和演化历史。通过对上部熔岩的Cpx斑晶进行高精度化学分析，将其划分为3组，并对各组的成因进行了估计。Boninite是新发现的。介绍了在冲积阶段喷发的萨拉希火山的初步资料。对深部热液金属成矿进行了地质和地球化学研究，以了解其成因。变质玄武岩中水流体与绿泥石的反应对其锌、镍含量特征具有重要影响。热液流体地层水岩比在20左右，远高于计算值2 ~ 4.6。研究了玄武岩到玄武岩的海底变质热结构，证实了温度向下升高。变质底的剪切方向为NE-SW，上盘向SW方向移动。鞋底的基性角闪岩在与上覆超镁质岩石接触的几十米范围内表现出可变的流动结构。

1. We recognized a wide petrographical variation of peridotite, its deformational history, cystallographical change of minerals and origin of mylonites within the upper mantle section of the northern Oman ophiolite. High-PGE chromitite was also discovered.2. We classified the late-intrusive rocks into three types in terms of petrography. Komatititic extrusives were found associated with picrite basalt, a quench phase of the late intrusives.3. The segmetation structure of a mid-ocean ridge was estimated by the strutural change of gabbroic layers. Noritic gabbro intruding around the derivative magma chmabers around the segment center impose contact metamorphism of up to granulite facies on surrounding sheeted dike complex. The structure and evolutional history of the roof zone of magma chambers were clarified.4. The upper lavas can be classified into three groups by high-accuracy chemical analysis of their Cpx phenocrysts, and the genesis was estimated for individual groups. Boninite was newly found. Preliminary data on the Salahi volcanics that erupted at the obuduction stage were presented.5. Hysrothermal metal mineralization was geologically and geochemically examined to understand its genesis. Reaction between aqueous fluid and chlorite in meta-basalts is of vital importance for their characteristics of Zn and Ni contents. The water/rock ratio in the hydrothermal fluid formation is around 20, that is far higher than the calculated values, 2 to 4.6. The thermal structure of the ocean-floor metamorphism was examined in basalt to dolerite to confirm a temprature increase downward.7. The shear sense on the metamorphic sole is NE-SW and the hanging side was confirmed to have moved toward SW.The basic amphibolite of the sole demonstrates variable flow textures within several tens of meters from the contact with overlying ultramafic rocks.