摘要
分布于贺兰山脉北部的贺兰山群变质杂岩的主期变质作用达角闪麻粒岩相,其矿物组合特征与低压相系麻粒岩相似、利用共生矿物组合和矿物对的温度计、压力计估算主期变质温度740—764(?),压力460—501MPa。温度压力条件与低压相系的地热梯度线较接近,变质作用强度具面型分布的特征,与东部密云、冀东等地的麻粒岩相区相似,但变质压力明显低,压力类型也不同,应属不同构造背景下的变质产物。
The main metamorphism of the metamorphic complex of Helanshan Group distributed in the north part of Helan mountain reahed amphibolite-granulite transitional facies with mineral associations similar to those of low pressure granulite facies. The temperature and pressure condition is constrained by the stability fields of mineral associations, and a p-T condition of T=740—767℃ and p=460—501MPa for the peak metamorphism are obtained on the bases of geothermobarometry of available mineral associations and pairs. This p-T condition is close to the geothermal gradient of low pressure facies series on the p-T diagram. The metamorphic intensity is homogeneous and no metamorphic zone can be divided,which is the same with the granulite terrains in the east Hebei Province of china. However, the difference in pressure types suggests the distinct difference in tectonic setting.
出处
《矿物岩石》
CAS
CSCD
1992年第4期12-20,共9页
Mineralogy and Petrology
关键词
变质岩
杂岩
变质作用
温度
压力
North China massif
Helanshan Group
low pressure granulite facies
