亚稳态橄榄石相变与深源地震研究进展  

An advance in metastable olivine phase transformation and deep-focus seismicity

作　　者：刘雷[1] 杜建国[2] 易丽[2] 

机构地区：[1]中国地震局地质研究所,北京100029 [2]中国地震局地震预测研究所,北京100036

出　　处：《地震》2007年第3期41-49,共9页Earthquake

基　　金：地震科学联合基金项目(B07002;C07002);中国地震局地震预测研究所青年科技基金项目(QN200502);中国地震局地质研究所与中国地震局地震预测研究所联合资助

摘　　要：由于岩石圈俯冲板块内部温度低,在400km左右的深度橄榄石不发生相变,低压相的橄榄石便以亚稳态的形式进入更深的深度。高温高压实验研究表明,亚稳态橄榄石相变机制以相变形成的超塑性透镜状尖晶石反裂纹破裂为深源地震的触发机制,能很好的解释深源地震的特征。亚稳态橄榄石在俯冲带中存在的范围,是制约亚稳态相变机制的重要因素。然而亚稳态橄榄石在俯冲带存在的范围尚存争议,不同模型给出结果相差较大,文中给出一些解决这个问题的建议。The phase transformation from olivine to spinel-phase can not take place because of lower temperature in the subducted slab at a depth of 400 km, and the olivine can be carried into the larger depth and becomes the metastable phase. According to the metastable olivine phase transformation faulting mechanism, deep-focus seismicity was triggered by anticrack formed in the superplastic lens-like spinel-phase. The depth is one of the most vital factors for phase transformation mechanism of the metastable olivine. Up to now what are the depths for metastable olivine existing are still an open question because of geothermal and compositional variations. Therefore, the results estimated from the different models are dissimilar. Some suggestions are proposed for solving the questions.

关 键 词：橄榄石 亚稳态相变 深源地震 高温高压 

分 类 号：P315.2[天文地球—地震学]