长石在高温高压条件下的物理化学行为  

Feldspars under conditions of high temperature-high pressure.

作　　者：刘曦[1,2] 胡张翼 邓力维[1,2] 

机构地区：[1]北京大学造山带与地壳演化教育部重点实验室,北京100871 [2]北京大学地球与空间科学学院,北京100871

出　　处：《岩石学报》2010年第12期3641-3650,共10页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(40872033)资助

摘　　要：长石是地学上非常重要的矿物之一。它有可能随着板块俯冲而进入地球深部,因此它在高温高压条件下的相行为以及物理化学性质对地球深部地球动力学研究非常有意义。本文总结了长石端员组份(钾、钠、钙长石)以及其固溶体系列已知的高温、高压实验数据,并绘制成相图。已有的研究成果显示:这三种端员组份在高压下的相行为有较大差异,并产生了许多只在高温高压条件下稳定的相如K-Holl-I、K-Holl-II、CF、CAS及CaPv等。由这些高压相构成的具有长石成分的不同相组合的密度在约5~23GPa的压力范围内超过地幔岩的密度,因此这些相组合可以主动俯冲到上地幔的深处。另一方面,已有研究表明,这些高压相对碱金属及碱土金属在地幔中的赋存状态有着非常重要的影响。As one of the most important minerals in geology,feldspar might enter the deep interior of the Earth via slab subduction process.Consequently,its phase relations and physical-chemical behaviors at high pressures could be very significant to the geodynamic process of the Earth's interior.Here we summarized in some phase diagrams all known high pressure-high temperature experimental data about feldspars with various compositions.These phase diagrams evident that a full picture about feldspar at high pressure is still unavailable,so that further high-pressure experimentation is necessary.Additionally,we briefly reviewed the available physical properties of the high-pressure phases derived from the feldspar compositions,and integrated them into pressure-density profiles which were subsequently compared to the pressure-density profile of pyrolite.The comparison suggested that the density of the different high-pressure phase assemblages for the feldspar compositions is larger than that of the pyrolite for the pressure interval of ~5 to 23GPa,leading to positive sinking into the upper mantle of the Earth.

关 键 词：地球动力学过程 长石 高温高压 相图 

分 类 号：P584[天文地球—岩石学]