Geodynamics of generation of oceanic crust-an example of the Oman ophiolite

总结了每一组的研究结果。地幔组阐明了地幔过渡带熔体与地幔之间的相互作用。此外，他们的互动是相当不同的地方。河砂尖晶石分析表明，与大洋地幔相比，阿曼蛇绿岩中的地幔橄榄岩高度亏损，表明岛弧晚期发生了明显的变质作用或地幔橄榄岩的形成。辉长岩群围绕着两个以前被认为是连续杂岩的系列，分别形成于大洋脊下前进和消亡的岩浆房。这可以用重叠的洋脊来解释，在这些洋脊上出现了扩张和后退或海脊。通过阿曼北部蛇绿岩区域精细地质填图，确定了出现厚莫霍面过渡带的脊段中部。从中央到尖端或脊段，矿物成分或层状辉长岩从演化程度较低的到演化程度较高的系统地变化。上地壳群测量了阿曼北部蛇绿岩大片地区的岩脉方向和厚度。他们发现，每隔几公里长，堤坝的方向就会有所不同，这表明海洋脊线的分割顺序最小。由辉长岩和地幔橄榄岩的岩石学特征推测，岩脉厚度从脊段中部向脊段顶端较大范围地增加。在阿曼蛇绿岩下变质岩底的面理面上，构造群发现了两种不同的矿物线理。他们还澄清说，即使在一个露头上，择优取向的程度也是相当不同的。

The results obtained from this research project are summarized for each group.Mantle group clarified an interaction between melt and mantle in the mantle-crust transition zone. Also they round the interaction was quite hetrogenous palce to place. Analyses of spinel using river sand show that the mantle peridotites of the Oman ophiolite are highly depleted compared to oceanic mantle, suggesting that signiricant modification or the mantle peridotite occured during later island arc stage.Gabbro group round two series of gabbros previously regarded as successive complex, which were formed at advancing and dying magma chambers beneath ocean ridges, respectively. This is explained by overlapping ocean ridges where propagation and retreating or ridges appeared. The central part of ridge segment where thick Moho transition zone occurs was determined through regional detailed geological mapping in the northern Oman ophiolite. From the central part to the tip or ridge segmenl, mineral compositions or layered gabbro varies systematically from less evolved to more evolved compositions.Upper crust group measured direction and thickness of dikes from extensive area in the northern Oman ophiolite. They found that the direction of dikes varies for each several km length, indicating the smallest order of segmentation of ocean ridges. The thickness of dikes increases from the central part to tip of the ridge segment in more large scale which is presumed from the petrological features of gabbro and mantle peridotite.Structural group found two different mineral lineations on foliation plane in the metamorphic sole beneath the Oman ophiolite. Also they clarified that the degree of preferred orientation is quite various even in one outcrop.