摘要
通过对孔兹岩系分布、产状,和麻粒岩的关系,推断孔兹岩系的形成演化经历了三个阶段:(1)2500-2400Ma,华北克拉通形成,为孔兹岩系提供了陆缘沉积物质。(2)2400-2000Ma,由于地壳的引张,出现克拉通盆地沉积,主要砂泥质、碳酸盐岩沉积,孔兹岩系原岩形成。(3)2000-1800Ma,拉张作用的进一步发展,在未形成新洋壳的情况下进而发生陆一陆碰撞,使盆地关闭。孔兹岩系卷入下地壳,发生变形变质,高压麻粒岩沿对接带上侵发生减压,高压麻粒岩和孔兹岩岩片、镁铁质岩一同,以混杂岩带的形式产出。
By the khondalite suites＇ distribution, occurrence, and relation ship with granulite it may be deduced that the formation and evolution of khondalite suites have undergone three stages： firstly, at 2.5-2.4 Ga, the North China craton is formed and provided continental sediment for the khondalite suites. Secondly, at 2. 4-2.0 Ga, with the crust stretching the eraton basin deposit oecured, the sediments predominantly are sands, pelites and carbonates, and the original rock of the khondalite suites was formed. Lastly, at 2. 0-1.8 Ga, the crust stretch was further developed, then the continent-continent collision occured while the new ocean crust wasfft formed, and the basin was closed. The khondalite suites dropped into lower crust, then metamorphicose took place, the high-pressure granulite intruded upward along burr zone, and de-pressure took place, it oecured as mingled rock belts together with the khondalite suite and mafic rock.
出处
《西部探矿工程》
CAS
2006年第3期121-123,125,共4页
West-China Exploration Engineering
关键词
晋冀蒙交界地区
孔兹岩系
构造演化
Jin-Ji-Men borderland
khondalite suites
tectonic evolution
