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在意大利西阿尔卑斯Sesia带,早阿尔卑斯蓝片岩相到榴辉岩相的长英质成分的变质岩石,在大于150km~2的范围内产生了同样的高压组合:石英、钠辉石、钠角闪石、钠云母、多硅白云母、黝帘石、石榴石、磁铁矿、榍石和铁硫化物(即QFS组合),经过连续反应的长英质组合的个别相在矿物化学上的变化反映了整个区域相对的压力和温度梯度。该地区的QFS组合中没有出现矿物学上的不连续性,从该研究区的西南部到东北部辉石中,硬玉的含量(Xid=0.48～0.93,角闪石中蓝闪石的含量(XGL=0.89～0.96)都有增加,共存石榴石辉石的分析结果表明,角闪石和辉石的这种成分变化,与共存石榴石中钙铝榴石组分减小相伴。辉石和石榴石的环带以及矿物化学方面区域性的变化趋势表明与增压相应QFS组合的演化,可以通过压敏连续反应模式化,在这些反应中,角闪石、黝帘石和大量更富硬玉的辉石构成高压组合,用化学图解控制能将那些模式化的连续反应的化学成分等值线定位于温—压空间,这些反应涉及的矿物相与自然组合中观察到的结构,化学判据是相符合的。这些等值线低的dP/dT梯度(—20kb/℃)连续反应可用于压力比钠长石完全分解成硬玉加石英的压力更高的地质测压计算中。此外还计算了有可能用为地质压力计的其他连续反应和包括NaAICa_(-1)Mg_(-1)置换或MgCa_(-1)置换的假二元100p循环。利用矿物化学与等值线的对比产生了一个该研究区的相对测压图表。借助于这种压力研究,能够证明Sesia地体最终记录下的状态运动的P—T途径是一个增压金陉,并讨论了Syros和Signos含长英质成分岩石所产生的另一些蓝片岩、榴辉岩。
The metamorphic rocks of the Early Cretaceous composition of the Early Alpine blue schist facies to the eclogite facies in the Sesia Belt of the Western Alps of Italy produce the same high pressure assemblages within the range of greater than 150 km 2: quartz, sodium pyroxene, sodium horn flash The mineralogical changes of the individual phases of the felsic assemblages after successive reactions are characterized by the presence of various types of rocks, such as quartz, paragonite, phyllosite, zoisite, garnet, magnetite, gallstone and iron sulfide The relative pressure and temperature gradient throughout the area. There is no mineralogical discontinuity in the QFS assemblage in this area. The content of jadeite (Xid = 0.48-0.93, the content of glaucophane in amphibole from the southwestern part of the study area to the pyroxene in the northeast) XGL = 0.89 ~ 0.96), and the analysis of the coexisting garnet pyroxenes showed that the composition of amphiboles and pyroxenes changed with the decrease of the components of the garnet in the coexisting garnets, and the pyroxene and garnet The zonal and mineralogical zonality trends indicate that the evolution of the QFS combination corresponding to pressurization can be modeled by a pressure-sensitive continuous reaction in which amphibole, zoisite and a large number of jadeite-rich pyroxene Constitute a high-pressure combination that is chemically controlled by chemical patterning to locate the chemical composition contours of those modeled continuous reactions in the warm-pressure space, the structures and chemical criteria observed for the mineral and natural combinations involved in these reactions are consistent Of these contours. The continuous dP / dT gradient (-20 kb / ° C) can be used in geotechnical pressure calculations with pressure higher than albite complete decomposition into jadeite plus quartz. Used as a gauge of geology Continuous reaction and a pseudo-binary 100p cycle including substitution of NaAICa_ (-1) Mg_ (-1) or MgCa_ (-1). Comparing the mineralogy with the contour, a relative manometry chart of this study area was generated. Using this stress study, the P-T pathway that could demonstrate the eventual state of motion ultimately recorded by the Sesia terrane was a booster gold and discussed other blue rocks produced by Syros and Signos with quartzitic rocks, Eclogites.