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甘、青交界处民和县史纳村一带早元古宙湟源岩群表壳岩属一套“有层无序”地层，岩石组合为石英岩、绢云（二云）石英片岩、黑云斜长石英片岩、含榴（十字）二云石英片岩、角闪片岩等。晋宁旋回主要发生了区域动力热流变质作用，出现了从低绿片岩相—低角闪岩相的递增变质带，高峰期变质条件Ｐ＝３．８×１０８～４．８×１０８Ｐａ，Ｔ＝５５８～６４５℃。该套岩层具“褶叠层”性质，新测得Ｓｍ－Ｎａ全岩等时线年龄为１９００Ｍａ，为古元古代地质事件。变质作用Ｐ－Ｔ－ｔ轨迹具逆时针特征，表明此时为活动大陆边缘或是大陆岛弧环境。地质、地球化学资料表明湟源岩群表壳岩形成于大陆边缘裂谷环境，碎屑岩Ｎａ２Ｏ＋Ｋ２Ｏ＝５．２８×１０－２，Ｖ／Ｎｉ＝７，Ｓｃ／Ｎｉ＝１，Ｓｃ／Ｓｒ＝０．１。
Gansu and Qinghai Junction, Shina Village, Minhe County The Early Proterozoic Shuiyuan Group of Rocks is a set of “stratum disorderly” strata. The rock assemblages are quartzite, sericite (second cloud) quartz schist, black Cloud plagioclase quartz schist, garnet (cross) dolomite schist, hornblende schist and so on. The hydrothermal metamorphism of the Jinning cycle took place mainly in the area, with an increasing metamorphic zone from low-greenschist facies to low-amphibolite facies. The peak metamorphic conditions were P = 3.8 × 108-4.8 × 108Pa and T = 558 ~ 645 ℃. The suite of rock “fold” layer of nature, the newly measured Sm-Na whole rock isochron age of 1900Ma, Paleoproterozoic geological events. Metamorphism The P-T-t track has a counterclockwise signature, indicating an active continental margin or a continental island arc at this time. Geological and geochemical data show that the source rocks are formed in continental rift environment. The clastic rocks have Na2O + K2O = 5.28 × 10-2, V / Ni = 7, Sc / Ni = 1 and Sc / Sr = 0.1.