近20年来，地球科学家们更加注意地外物体对地球的碰撞冲击作用及其产物和地质历史记录的研究，特别是那些突发性的巨大地外撞击作用及其诱发灾变事件，已成为当今地球科学界举世瞩目的重大问题。尤其是90年代以来，国外一些专家把注意力转到过去未被重视的某些地史时期特殊沉 For nearly 20 years, geoscientists have paid more attention to the collision impact of extraterrestrial objects on the Earth and the study of their products and geological history, especially those unexpected huge extra-continental collision effects and their induced catastrophic events that have become the current earth The world’s major issues of scientific interest. Especially since the 1990s, some foreign experts have turned their attention to some special geo-history periods that were not valued in the past