【摘要】 地质、地震测深、大地电磁测深、重磁场特征和古地磁综合研究结果表明 ,阿拉善—敦煌陆块是具有完整、统一的前寒武系结晶基底的刚性块体。它的西界位于若羌—星星峡断裂 ;东界位于贺兰山 ;南缘楔入青藏高原之下 ;北缘插入兴蒙古生代褶皱系之下 ,范围颇大 ( 91°E～ 10 6°E ,38°N～ 4 2°N)。阿拉善—敦煌陆块是华北地台重要组成部分 ,它不但阻挡了印度板块挤压主应力的向北传递 ,而且把塔里木地台和华北地台紧密连接在一起 ,组成更加巨大的中华地台更多还原

【Abstract】 Integrated geologic,seismic sounding,gravity and magnetic field and paleomagnetic studies show that the Alxa Dunhuang landmass is a rigid block with a complete,unified Precambrian crystalline basement.Bordered by Ruoqiang Xingxingxia fault on the west and Helan Mountain on the east,and wedging itself beneath Qinghai Tibet plateau on the south and Xingmeng Paleozoic fold system on the north,it occupies a rather large area(91°E～106°E,38°N～42°N).Being an important component part of the North China platform,the Alxa Dunhuang landmass not only hindered the northward transmission of compressive principal stress of the Indian plate but also caused the close connection of the Tarim platform with the North China platform to form the greater Chinese platform.更多还原