中朝与扬子板块的鉴别特征

本文强调了要从地质演化历史过程中,综合运用地质、地球化学、地球物理的资料来对比及鉴别不同板块的特征。综合运用结晶基底的形成时间,某些元素的含量、某些元素的比值,铅同位素比值的变化,地幔包体中稀土元素配分曲线的特征,中元古界是变质的还是沉积的,晋宁事件的存在与否,震旦纪冰碛层的特征,早寒武纪含磷岩系与黑色页岩系的存在与否,400Ma前后的沉积间断,晚古生代煤系地层的发育特征,板块运移距离的大小,岩石圈的厚度,平均P波速度与剪切波速度的差异、壳内低阻层的存在与否等特征就可鉴别中朝与扬子板块。认识这些特征,将有助于弄清东亚地区其他小地块(如朝鲜半岛南部地块,Hida地块,柴达木地块和塔里木地块等)的归属问题。

Distinctive Characteristics of Sino-Korean and Yangtze Plates

The paper emphasizes that different plates can be distinguished by synthesizing geological, geochemical and geophysical characteristics. The Sino-Korean and Yangtze plates are characterized by such features as the formation time of the crystallization basement, content of some elements and the content ratio of some elements in the crust and mantle, variation of lead isotopic ratios, the chondrite-normalized REE pattern in mantle inclusions , the nature of the Middle Proterozoic system: metamorphic or sedimentary, the existence of the Jinning event (about 850 Ma), P-bearing and black shale series of the Early Cambrian, depositional breaks about 400 Ma, the development of coal measures strata in the Late Paleozoic, moving distance of plates in the Paleozoic, thickness of the lithosphere, differences of average velocities of P waves and shear waves, the existence of low-resistivity layer in the inner crust.