【摘要】 前寒武纪地壳以其独特的岩石组合以及构造类型在地球演化的进程中扮演着举足轻重的作用,本文简要描述了前寒武纪地球演化中的特殊地质现象,并讨论其蕴涵的地球演化的可能的因果联系和时空关系。针对前寒武纪地球演化研究中的焦点问题,本文对可能模型的优缺点进行了一一论述。前寒武纪一级构造模式可能经历了由垂直方向运动为主的地幔柱模式向由水平方向运动为主的板块构造模式的转变。对于前寒武纪板块运动存在的检验,硬玉和红宝石则是很好的板块构造指示矿物。根据太古宙克拉通与元古宙克拉通之间的几何关系与时空演变的联系,笔者等认为2.4~2.2Ga很有可能是前寒武纪构造模式发生转折的关键期。其间发生的全球冰期事件和超级大陆的形成并无很强的相关性,但与海平面的高低直接相关,这很有可能是大洋块体俯冲下沉至地幔引起海水"倒灌"所致。此后,地球表壳岩的刚性特征即发生了变化。更多还原

【Abstract】 Precambrian Earth evolution is full of features characterized as some unique rocks and structural types almost without analogues in Phanerozoic Earth,and has played a great role in the evolvement of the Earth history.This paper will generally review some basic characteristics of those special geology phenomena,indicating the possible causal relationship and space—time connection between them.Regarding the focus issue in Precambrian Earth evolution,advantages and disadvantages of different models are illustrated here.The first order tectonic model might have changed from plume tectonics resulting vertical motion to plate tectonics leading to horizontal motion in the history of Precambrian Earth evolvement.To check the existence of Plate tectonic in Precambrian,jadeitite and ruby might be a new class of mineral indicators.Based on the geometry relationship between and space—time evolution of Precambrian Cratons and Proterozoic Cratons,we come to a conclusion that the critical period could be 2.4~2.2Ga when the geodynamic model began to change,of which the Global snow event has no direct correlation with Supercontinent but with sea level,which could be caused by ocean slab subducting and sinking into the mantle.Since then,the crust rigidity also began to change.更多还原