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出露于威海北部的古元古界荆山岩群，呈包体状零散分布在新元古代晋宁期荣成超单元中，经过区域对比，可将其划分为3个岩组共6个岩段。麻粒岩、石榴夕线黑云片岩、堇青石榴夕线黑云片岩、方镁石镁橄榄石大理岩及透辉石镁橄榄石大理岩等是荆山岩群经历过麻粒岩相变质作用形成的指示性岩石（组合）。麻粒岩相变质作用分为3个阶段：早期阶段T=550～600℃，P=0．2～0．55GPa，地热梯度平均38℃／km；峰期阶段T=700～820℃，P=0．71～1．0GPa，地热梯度平均26℃／km；晚期阶段T＜700℃，P=0．65GPa，地热梯度30℃／km。属低压区域变质相系。PT轨迹总体呈逆时针形式，表明本区麻粒岩相变质作用发生的大地构造环境靠近大陆边缘的岛弧区。
The Jingshan Group of Paleoproterozoic, exposed in the northern part of Weihai, was scattered in body form in the Neoproterozoic Jinning Period of the Cretaceous into super-units. After regional comparison, it can be divided into 6 groups of 3 rocks segment. Granulite, pomegranate dark linerock schist, cordierite duronite schist, peridotite forsterite marble and diopside forsterite olivine marble is the Jingshan group experienced granulite facies metamorphism Indicative rocks formed by the action (combination). The granulite facies metamorphism is divided into three stages: T = 550 ~ 600 ℃, P = 0.2 ~ 0.55GPa in the early stage, and the average geothermal gradient is 38 ℃ / km; in the peak period, T = 700 ~ 820 ℃, P = 0.71 ~ 1.0GPa, geothermal gradient average 26 ℃ / km; late stage T <700 ℃, P = 0.65GPa, geothermal gradient 30 ℃ / km. Is a low-pressure regional metamorphic facies. The PT trajectory is generally anticlockwise, indicating that the tectonic setting of the granulite facies metamorphism in this area is close to the island arc zone at the continental margin.