出溶白云石述评

REVIEW ON EXSOLUTION DOLOMITE

本文介绍了出溶白云石的定义和形成过程,并用晶体化学的观点强调了镁方解石在压力增高的情况下会通过阳离子的有序调整采取出溶形式向稳定矿物相白云石和方解石转变.温度升高虽然可使出溶速度加快,但低温对离子的有序调整更为有利.在自然界,不仅在变质条件下白云石可以从镁方解石中出溶出来,在正常海洋环境中,镁方解石沉积也可被适当压力诱发产生出出溶白云石.

The definition and formation process of exsolution dolomite are introduced in this paperIn. the light of crystal chemistry, we hold that magnesian calcite will transform to the more stable dolomite and calcite in the form of exsolution by orderly rearrangement of cations under increased pressure. Although the increased temperature could speed the exsolution, low temperature would be more favorable for the rearrangement of cations. Dolomite can exsolved not only from magnesian calcite under metamorphic conditions, but also from magnesian calcite sediments under a modest pressure in a normal oceanic environments.