定向压力对岩体及其矿物的影响
THE EFFECTS OF THE ORIENTED PRESSURE ON ROCK MASSES AND SOME MINERALS THEREIN
-
摘要: 前言地球本身就是一个应力场,赋存在地壳內的任何岩石及矿物都受到应力的作用,不过,应力效应有的明显,有的隐约。例如,我们经常见到的花岗岩,具花岗结构和块状构造,应力似乎对它并未起显著作用,可是,片麻状花岗岩的情况就不同了,它有明显的应力效应,产生片麻状构造。据此,我们称它为受应力作用的花岗岩,或广义的变质花岗岩。对于那些在岩浆固结过程中尚未完全固结之前,因受应力作用而形成的片麻状花岗岩及条Abstract: Some Syntectonic metamorphic granites are known to have undergone morphological changes under oriented pressures during their formation, which gives rise to special structures. Meanwhile some minerals such as quartz in the rock have also undergone such a change,i.e.the change from granular through lamellar up to banded structures. Zircon displays pressure-solution phenomena and has become that resembling the’ sediment-transported-type zircon. The cell dimension and refractive index N of garnet have also changed.Even plagioclase number may also show regular deviation. Likewise,the original moderate—pressure granulite was reconstituted by the intense oriented pressure into highpressure granulite with a characteristic mineral association, in which exsolved lamellar albite and exsolved k-f eldspar are developed. The former forms exsolved perthite,while the latter antiperthite. In addition, the pressure shadow of garnet is ready to be observed in the rock.