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海阳所堆积辉长岩由橄长岩、橄榄辉长岩和辉长岩组成。在橄长岩和橄榄辉长岩中发育有典型的变质反应结构 :主要为橄榄石与斜长石之间形成由斜方辉石、尖晶石、角闪石和石榴石等矿物组成的多期次次变边 ,并有三个不同世代变质矿物 ,早期Cpx +Opx +Spl,中期Amp ,晚期Grt ;其次是钛铁矿与斜长石之间形成石榴石次变边 ,相对比较简单 ,只有一个世代变质矿物 ,为Grt+Amp +Rut或Grt+Rut。岩石中石榴石是通过斜长石与角闪石或斜长石与钛铁矿之间的变质反应形成的 ,虽为峰值变质作用的产物 ,但变质反应的期次及类型不同导致了所形成石榴石的温度和压力有所不同。堆积辉长岩形成演化的温压计算表明 ,堆积辉长岩在经过近等压降温的岩浆作用之后的变质作用早期 ,仍为近等压降温 ,而晚期则表现为近等温升压。这一特殊的P T演化可能反映了堆积辉长岩冷侵位与深俯冲特征
The gabbro deposits in Haiyang consist of gabbro, olive gabbros and gabbro. There is a typical metamorphic reaction structure in the gneiss and olive gabbro: the main period between olivine and plagioclase is the formation of multi-phases consisting of orthopyroxene, spinel, hornblende and garnet There are three different generations of metamorphic minerals, early Cpx + Opx + Spl, intermediate Amp, late Grt; followed by garnet subclassed between ilmenite and plagioclase, which is relatively simple, with only one Generations of metamorphic minerals, Grt + Amp + Rut or Grt + Rut. The rock garnet is formed by the metamorphic reaction between plagioclase and amphibolite or plagioclase and ilmenite, though it is the product of the peak metamorphism. However, the different stages and types of metamorphic reactions lead to the formation of Garnet temperature and pressure are different. The temperature and pressure calculation of the accumulation and evolution of the gabbro indicates that the gabbro is still near-isobaric pressure in the early stage of metamorphism after nearly equi-pressure cooling magmatism, and nearly isothermal pressure-rising in the late period. This particular P T evolution may reflect the cold emplacement and deep subduction of the gabbro