岩浆脱气动力学研究进展

REVIEW OF STUDIES ON DYNAMIC MODEL OF MAGMA DEGASSING

岩浆脱气动力学是地球动力学的一个重要方面。介绍了H2 O和CO2 在岩浆中溶解、气泡成核、气泡生长与上升以及岩浆喷发等过程的研究成果。由前人的研究结果可知 ,压力降低使得气体在岩浆中过饱和是气泡形成的主要原因 ;气体过饱和度增大加速气体的释放和气泡的生长 ,进而导致岩浆的浮力增大 ,岩浆上升速度加快 ;气泡膨胀和加速作用发生在岩浆爆裂之前 ,并且是引起爆裂的真正原因。此外 ,CO2 的溶解度较小和岩浆中CO2 含量较高是气泡中CO2 含量高的主要原因。同时也指出 ,文献中的模型与岩浆喷发的实际情况相比 ,体系成分过于简单 ,还有待进一步完善。对岩浆脱气动力学研究作了客观评价和展望。

Magma degassing dynamics is an important aspect in geodynamics. This article introduces carbon oxide solubility model, bubble growing and ascending model, and magma eruption model. Analysis on previous research results show that pressure decrease leads to volatiles super saturation, which is the main reason of bubble formation. The volatiles super saturation increases with decrease of pressure, which accelerates degassing and bubble growing and results in magma density decreasing, buoyancy increasing, and magma accelerating ascend. So expansion and acceleration precede, and fragmentation indeed caused. In addition, carbon oxide has very small solubility which results in that CO 2 is the prime component in bubbles. The systems mentioned in this article is too simple comparable to the facts. The next step for our research is proposed.