摘要
本文提出了冀东黑云母片麻岩—H2O系统在0.1一0.2GPa压力下熔融买验的相关系。其固相线温度分別为0.1GPa时762℃,0.2GPa时712℃。黑云母消失的温度分別为0.1GPa时787℃,0.2GPa时737℃,石英消失的温度分别为0.1GPa时837.℃,0.2GPa时787.℃。采用Burn-ham模型计算的在液相线温度下岩浆饱和水的含量分別为0.1GPa时3.8%与0.2GPa时5.8%。根据实验结果以及早前寒武纪时冀东陆壳的古地温可知,该区早前寒武纪角阿岩相岩石分布的地区广泛出现的混合岩化作用应主要归因于陆壳岩石(黑云母片麻岩等)的局部熔融作用。由实验结果以及现代冀东陆壳的地温可推知,壳内低速层可能不是由岩石局部熔融所引起,而是由岩石中含有隙间水流体引起。
This paper presents the phase relationships in the biotite gneiss-H_2O system by melting experiment at 0.1-0.2 Gpa pressures. The solidus temperatures are 762℃ at 0.1 Gpa and 7122℃ at 0.2 Gpa. The biotite-out temperatures are 7872℃ at 0.1 Gpa and 7372℃ at 0.2 Gpa, while the Quartz-out temperatures are 8372℃ at 0.1 Gpa and 7872℃ at 0.2 Gpa. Using Burnham model (1979), the estimated H_2O-solubility of the biotite gneiss melt at liquidus temperature is 3.8% at 0.1 Gpa and 5.80% at 0.2 Gpa. Based on the results of the melting experiment and the paleogeotherm of the early Preeambrian continental crust in eastern Hebei Province, the widespread migmatization of the early Precambrian amphibolite facies rocks in the region may result mainly from the partial melting of the crustal rocks (biotite gneiss). The experiment results and the present geotherm in this region suggest that the crustal low-velocity layer may result from the presence of interstitial hydrous fluids rather than the partial melting.
出处
《岩石矿物学杂志》
CAS
CSCD
1991年第2期105-113,共9页
Acta Petrologica et Mineralogica
关键词
片麻岩
熔化
黑云母
eastern Hebci Province
biotite gneiss
melting experiment
migmatization
crustal low-velocity layer
