【摘要】 内蒙古固阳地区发育高镁闪长岩(赞岐岩,sanukitoids)-角闪花岗岩类。其中高镁闪长岩的地球化学特征类似于晚太古代形成于板块消减带之上的地幔楔的sanukite(赞岐岩)。Sanukite以富MgO、Mg#、Cr和Ni为特征,在国外许多太古代地体中均有发现。本文报导了固阳地区高镁闪长岩(2556±14Ma)和角闪花岗岩(2520±9Ma)的SHRIMPU-Pb年龄。这一研究表明华北块的消减作用可能始于晚太古代晚期。国外报道的太古代sanukite出现在3.0-25Ga之间,最晚的为印度Dharv(?)ar克拉通的sanukites(2.51-2.55Ga)。因此,华北与印度可能是地球上板块构造发育时间最晚的。更多还原

【Abstract】 High-Mg diorite - hornblende-granite occurs at Guyang, Inner Mongolia. Geochemically, the high-Mg diorite is similar to late Archean sanukite that was formed in mantle wedge above subduction zones. Sanukite, which finds common in Archean terrains worldwide, is characterized by high MgO content and high Mg associated with enrichments of Cr and Ni. This paper reports SHRIMP U-Pb ages of a high-Mg diorite (2556±14 Ma) and a hornblende-granite (2520±9 Ma) in the Guyang area. Accordingly, the subduction of the North China plate possibly initialed during the late times of the late Achaean. The Archean Sanukites outside of China have been well documented in the range of 3. 0- 2. 5 Ga with the youngest (2.51- 2. 55Ga) occurring in the Dharwar Craton of India. It is suggested that the North China and synchronous India could be the latest areas developing plate tectonics on Earth.更多还原