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俯冲带中流体与岩石相互作用以及流体循环一直是地质学家关注的焦点之一.硬玉岩(翡翠)作为高档宝玉石材料,其成因一直备受关注.硬玉岩产于与俯冲带有关的蛇纹石化超镁铁质岩中,是俯冲带中流体与超镁铁岩相互作用的特殊产物.岩石组合、岩相学、显微结构及矿物化学特征表明:橄榄岩与流体的作用可以分为5个阶段,分别为蛇纹石化→(绿泥石、金云母)→角闪石→辉石→(方沸石、钠长石)阶段.结合热力学相图,总结了橄榄岩与流体作用过程中矿物的演化序列.硬玉岩的形成需要富Na、Al、Si流体和较高的压力.缅甸硬玉岩中,钠质闪石总是与硬玉岩伴生,钠质闪石成分变化大,且能与流体发生再平衡从而调节自身和流体的成分.钠质闪石在硬玉形成过程中充当了Na、Al、Si的缓冲剂,使Na、Al、Si达到一定比例有利于硬玉的结晶.
Fluid-rock interaction and fluid circulation in the subduction zone have always been one of the focuses of geologists, and the cause of jadeite jadeite (jadeite) has been attracting much attention as a high-grade gemstone material. In lithic-petric ultramafic rocks, it is a special product of the interaction between fluids and ultramafic rocks in the subduction zone.The rock assemblages, petrography, microstructure and mineralogical characteristics show that the action of peridotite and fluid can be divided into 5 stages, namely, serpentinization → (chlorite, phlogopite) → hornblende → pyroxene → (analcite, albite) stage.Combined with the thermodynamic phase diagram, summarized the peridotite and fluid interaction The evolutionary sequence of minerals. The formation of jadeite requires rich Na, Al, Si fluids and high pressure. In Burma jadeites, sodium amphiboles are always associated with jadeites, and the composition of sodium amphiboles varies greatly, The fluid rebalances and thus regulates the composition of the fluid itself.Ammobite acts as a buffer for Na, Al and Si during the formation of jadeite, resulting in a certain ratio of Na, Al and Si to the crystallization of jadeite.