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中国大陆科学钻探工程5000m主孔位于苏鲁超高压变质带南部。该钻孔0～2000m主要由榴辉岩、片麻岩、石榴石橄榄岩和少量片岩和石英岩组成。累积厚度达1000多米的榴辉岩具有不同的矿物组成、不同的矿物含量和不同的全岩化学成分,可划分成富Si的石英榴辉岩、富Ti的金红石榴辉岩、富Al的多硅白云母和蓝晶石榴辉岩、富Mg的双矿物榴辉岩和具有正常玄武岩成分的普通榴辉岩。榴辉岩的原岩包括基性层状侵入岩和变质表壳岩。榴辉岩全岩成分对石榴石和绿辉石中某些化学组分的含量有明显控制,而且直接影响到变质条件估算的准确性。扩散成分环带的广泛发育表明超高压矿物在早期退变质过程中发生了成分再平衡。这一事实以及具有成分生长环带石榴石变斑晶的存在,为榴辉岩形成在更高温度(>940℃)和更高压力(>4.5GPa)条件下提供了有力的证据。
The 5000m main hole of the Chinese mainland scientific drilling project is located in the southern part of the Sulu UHP metamorphic belt. The borehole is mainly composed of eclogite, gneiss, garnet peridotite and a few schist and quartzite. Eclogites with a cumulative thickness of more than 1000 meters have different mineral compositions, different mineral contents and different whole-rock chemical compositions and can be divided into Si-rich quartz eclogites, Ti-rich eclogite eclogite, and Al-rich Muscovite and kyanite pumice, Mg-rich dual-mineral eclogite and normal eclogites with normal basalts. The protoliths of eclogite include basal layered intrusions and metamorphic crust rocks. The eclogitic whole rock composition has obvious control over the content of some chemical components in garnet and omphacite, and it has a direct impact on the accuracy of estimation of metamorphic conditions. The widespread development of the diffuse component annulus suggests that composition re-equilibration occurred during the early retrograde metamorphism of ultra-high pressure minerals. This fact as well as the presence of garnet speckle with a component growth zone provide strong evidence for the eclogite formation at higher temperatures (> 940 ° C) and higher pressures (> 4.5 GPa).