Pressure and Temperature Conditions Recorded by the Beni-Bousera Ultramafic Body and the Overlying Lower-crustal Rocks(Rif,Morocco)

The Beni Bousera massif(Rifean belt,northern Morocco)is predominantly composed of spinel lherzolite with subordinate garnet pyroxenite and garnet peridotite layers.It formed an antiformal dome which was overlain by graphite-sillimanite-garnet gneisses(kinzigites)equilibrated at around 1 GPa and 750℃.Within these kinzigites,kyanite-bearing basic granulites record somewhat higher PT conditions of around 1.6-2.0 GPa and 760-820℃.Garnet clinopyroxenite(either graphite-bearing or graphi-

西北太平洋边缘的右行剪切和印度—欧亚板块的碰撞

由于喜马拉雅区碰撞的结果,亚洲大陆及远至其环太平洋俯冲带后的东界,都在进行着变形。Tapponnier等(1982)提出南中国海的张开与第三纪时印支沿红河断裂的挤出有关(图1)。但是,南中国海仅是同一时期内张开的数个边缘盆地之一,其他例子尚有日本海。

鄂霍茨克-日本海地区新生代陆内右旋运动

1 绪言一个具有地壳地震活动的活动变形扩散带沿着黑龙江地区和鄂霍次克海之间的萨哈林延伸(图1)。人们对于这个带作出了各种解释,Jolivet 等(1990)对这些解释进行了讨论。Chapman 等(1976)根据几个大地震震源机制的研究,认为一个活动压缩带与萨哈林的走向垂直。他们把这个变形归因于北美板块(NAM)相对于欧亚板块(EUR)的运动。