论文部分内容阅读
静高压合成柯石英的压力和温度的实验条件是提出地球板块折返假说的基础。然而,静高压没有反映局部碰撞和剪切应力的因素。本文考虑了这些因素,提出了一种利用高能机械球磨与静高压相结合的,可以模拟地表柯石英合成的实验室研究方法。发现了存在一个机械球磨时间阈和一种由机械碰撞引起的α-石英中间亚稳相,其静高压致晶化成柯石英的条件为3.0 GPa,923 K,小于1.0 min。沿袭传统的板块折返假设,对应此条件的板块俯冲深度应比Coes的结果浅20 km。发现了10 s量级的柯石英的短时间快速合成现象。此方法合成的柯石的Raman峰,涵盖了以前得到的天然柯石英和人工合成的柯石英的Raman信息。阐明了此方法合成的柯石英在地质科学上的含义, 并提出另一种可能的地表柯石英形成机制。
The experimental conditions for the pressure and temperature of static high pressure synthetic coesite are the basis for the hypothesis of reentry of the Earth plate. However, static high pressure does not reflect the factors of local impact and shear stress. In this paper, we consider these factors and propose a laboratory research method which can simulate the synthesis of surface coesite by using the combination of high energy mechanical milling and static high pressure. It was found that there was a mechanical milling time threshold and an α -quartz intermediate meta-stable phase caused by mechanical collision. The conditions of static high pressure crystallization into coesite were 3.0 GPa and 923 K, less than 1.0 min. Following the traditional plate fold return hypothesis, the plate subduction depth corresponding to this condition should be 20 km shallower than Coes’ result. The short-time rapid synthesis of coesite of the order of 10 s was found. The Raman peak of coesite synthesized by this method covers the Raman information of previously obtained natural coesite and synthetic coesite. Clarified the geological meaning of coesite synthesized by this method and proposed another possible formation mechanism of surface coesite.