Physical changes of andesite：
(1) Andesite will be eroded, transported, and deposited through the river for a long time, and finally settled into a quiet water body and turned into shale.
(2) If the andesite is deeply buried to a temperature of about 300 to 500 ° C, a schist will be formed under the pressure of about 2 to 6 Kb.
(3) Andesite is corroded by acidic hydrothermal fluid, and an altered andesite, also known as Qingyanyan, is formed at a temperature of about 100-200 °C.
(4) Andesite is often altered into a Qingyanyan under the action of hydrothermal fluid. Such altered products are fine aggregates of epidote, chlorite, albite, sericite, quartz and carbonate minerals, which are important prospecting indicators for lead, zinc and silver.
Andesite and basalt often have a transitional relationship, and they are often symbiotic in the occurrence. It is difficult to distinguish them by naked eye, chemical analysis or microscopic identification. At this time, the transitional rock can be designated as basaltic-andesite or Anshan-basalt.
