一类 of the same class; of the same category; of the same species◇一类商品 classⅠgoods; 一类物资 means of production in categoryⅠ; supplies under categoryⅠ; classⅠmaterials
Comparing with other rocks , black shales are actually a series of sedimentary rocks enriching sulfide minerals , organic matters and trace elements such as v , ni , mo , cu , zn etc . thorough studies of black shales weathering have important theoretical , economic and environmental values 与其它岩石类型相比,黑色页岩是一类富含硫化物、有机质以及v 、 ni 、 mo 、 cu 、 zn等微量元素的沉积岩,对该类岩石进行化学风化作用研究具有重要的理论、环境和经济价值。