The retrogressive metamorphism of eclogites took place in three stages in Weihai area.In the first stage, primary omphacite was broken down into sodic clinopyroxene and plagioclase.

• 威海地区榴辉岩退变质过程表现为三个阶段：第一阶段，原生绿辉石分解形成钠质单斜辉石+斜长石合晶体；