碰撞与花岗岩——碰撞是构造事件,不是构造环境

Collision and granite: Collision is a tectonic event,not a tectonic environment

碰撞与花岗岩的关系是学术界关心的问题,但是,当前在碰撞与花岗岩关系的研究中存在许多误区。本文认为,碰撞是地壳浅部的构造事件,不属于构造环境范畴。碰撞本身不产生花岗岩,花岗岩形成需要热,热主要来自地幔,是来自地幔的热使下地壳底部熔融才形成了花岗岩。碰撞和碰撞后花岗岩地球化学性质不同,原因与碰撞或碰撞后无关,而与碰撞导致的地壳厚度变化有关。碰撞不是构造环境,现今所用的花岗岩构造环境判别图如果包含有碰撞的内容全部是错误的。

The relationship between the collision and the granite is a problem of common concern among geologists,nevertheless,many misunderstandings exist in the current study.This paper argues that collision is a tectonic event in shallow crust and hence does not belong to the category of tectonic setting.Granite is probably formed by the partial melting of the bottom of the lower crust.The formation of granite needs heat,and the heat mainly comes from the mantle.Collision can＇t produce granite.The differences of granite geochemistry between syn-collision and post-collision are related to the change of crust thickness caused by collision.So,the discrimination diagrams of tectonic settings,if they contain collision,are completely wrong.