中文摘要：

在北阿尔金的红柳泉一带，新识别出蓝片岩和榴辉岩的出露。它们与泥质片岩、钙质片岩和石英片岩等一起构成HP／LT变质带，与相邻的蛇绿混杂岩呈断层接触。根据估算的温度和压力显示榴辉岩形成的峰期温压条件为仁430-540℃，P=2．0-2．3GPa。分别对榴辉岩和蓝片岩中的多硅白云母和钠云母进行叩虹一誓心年代学测定．获得榴辉岩中多硅白云母的坪年龄为（512±3）Ma，等时线年龄为（513±5）Ma；蓝片岩中钠云母的坪年龄为（491±3）Ma，等时线年龄为（497±10）Ma。这些年龄资料显示北阿尔金HP／LT变质带形成时代可能早于北祁连HP／LT变质带．反映了北阿尔金一北祁连早古生代洋壳俯冲存在穿时性。

英文摘要：

Blueschists and eclogites are newly recognized in the Hongliuquan area, North Altyn Tagh. These blueschists and eclogites, together with metapelites, calcareous schists and quartz schists, form part of a coherent high-pressure （HP）/low-temperature （LT） metamorphic terrane, which occurs as a tectonic slab in faulted contact with ophiolidc melanges. P-T estimates show that the peak pressure-temperature metamorphic conditions for the eclogites were 2.0-2.3 GPa and 430-540℃. Phengite from an eclogite sample and paragonite from a blueschist sample were selected for Ar-Ar dating. Phengite from eclogites yields an Ar-Ar plateau age of （512±3）Ma and an isochron age of （513±5）Ma, and paragonite from blueschists gives an Ar-Ar plateau age of （491±3）Ma and an isochron age of （497±10）Ma. These new age data suggest that the North Altyn Tagh HP/ LT metamorphic belt probably formed earlier than the North Qilian HP/LT metamorphic belt and imply the existence of diachronism of subduction of the Early Paleozoic oceanic crust beneath the North Altyn Tagh- North Qilian.