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吉林省南部辉南-靖宇地区第四纪碱性玄武岩中的地幔包体主要为尖晶石相二辉橄榄岩和方辉橄榄岩。二辉橄榄岩和方辉橄榄岩的平衡温度分别为770～1000℃和850～1025℃,对应的氧逸度(fO2)值分别为FMQ-0.70至+0.34(均值为FMQ-0.06)和FMQ-0.46至+0.05(均值为FMQ-0.15),它们与深海橄榄岩(abyssal peridotites)以及软流圈地幔的fO2相似。橄榄岩的fO2值,连同其全岩化学成分(如Mg#、Al2O3、CaO、Ni、Co和Cr)和矿物化学成分(如橄榄石的Fo、尖晶石的Cr#和Mg#,以及辉石的Mg#)特征,表明辉南-靖宇地区龙岗火山群下面的岩石圈地幔很可能是在晚中生代以来,伴随着华北克拉通和扬子板块的碰撞以及来自东侧太平洋板块和北侧蒙古-额霍次克(Mongolo-Okhotsk)板块分别向西和向南的俯冲叠加,原来的古老岩石圈失衡、塌陷(拆沉?),取而代之的深部软流圈底辟、上涌,又经历了低度部分熔融的产物。
The mantle inclusions in the Quaternary alkaline basalts in the Huinan-Jingyu area, southern Jilin Province, are mainly spinel-peridotite and harzburgite. The equilibrium temperatures of the lherzolites and the harzburgites are 770-1000 ° C and 850-1025 ° C, respectively, and the corresponding values for fO2 are FMQ-0.70 to +0.34 (mean, FMQ-0.06) and FMQ -0.46 to +0.05 (mean, FMQ-0.15), which are similar to the fO2 of abyssal peridotites and asthenosphere mantle. The fO2 values of peridotites, together with their whole rock chemistry (eg Mg #, Al2O3, CaO, Ni, Co and Cr) and mineralogical compositions (eg Fo of olivine, Cr # and Mg # of spinel, It shows that the lithospheric mantle under the Longgang volcanic group in Huinan-Jingyu area is probably due to the collision of the North China Craton and the Yangtze Plate since the Late Mesozoic, The Mongolo-Okhotsk plate overlaps the subduction westward and southward, respectively, and the original paleolithic lithosphere is unbalanced, subsided (detachment?) And replaced by the deep asthenospheric uplifts, which experienced low Degree of partial melting of the product.