For decades , many geologists assumed that a series of distinct eruptions over millions of years must have occurred to produce the extensive bishop tuff .
数十年来,许多地质学家认为,过去数百万年必定发生了一连串的个别喷发,才能造成广大的毕夏普凝灰岩。
Shrimp u-pb zircon age of late mesozoic tuff ( lava ) in luanping basin , northern hebei , and its implications .
冀北滦平晚中生代火山碎屑(熔)岩中锆石shrimpu-pb年龄及其地质意义。
Surrounding rock is mainly compiling tuff , its apparent syndactyly and is dark volcanic programming reseda , false plagioclase , natrium feldspar and green shade stone wei crystal mixture , makes the surrounding rock is called hard rock hard grind .