To further understand the metamorphic evolution in the southern margin of the Jiao-Liao-Ji Belt in the Liaodong area, a detailed petrological and geochronological study was performed on representative metapelites from the South Liaohe Group. The peak metamorphic stage (M1) of the samples is represented by the mineral assemblage of garnet-biotite-plagioclase-sillimanite-quartz-magnetite in sample DD24-1 and garnet-biotite-plagioclase-ilmenite-quartz in sample DD24–2. The post-peak metamorphic stage (M2) is indicated by the appearance of cordierite with the mineral assemblage of biotite-cordierite-garnet-plagioclase-K feldspar-sillimanite-quartz-magnetite-ilmenite in sample DD24-1. The P-T calculations using pseudosections and conventional geothermobarometry imply that the M1, M2 and final retrograde stage (M3) metamorphisms occurred at 865–890 °C and 6.9–9.2 kbar, 840–860 °C and 5.3–6.2 kbar, and 570–670 °C and 3.3–4 kbar, respectively. The zircon SHRIMP UPb age data show that M1 metamorphism occurred 1867 ± 11 Ma and 1866 ± 8 Ma for samples DD24-1 and DD24–2, respectively. Together with previous studies, this study confirms that a low-P/T type granulite facies regional metamorphic event 1.87–1.84 Ga with a clockwise P-T path occurred in the South Liaohe and the Ji'an groups. Together with the simultaneous postcollisional igneous activity in the South Liaohe and Ji'an groups, the low-P/T type metamorphism indicates that postcollisional activity occurred in the South Liaohe and Ji'an groups during 1.87–1.84 Ga due to slab break off after the collision. Combined with the prevailing postcollisional activity in the Nangrim Massif on the Korean Peninsula, this study suggests that the Longgang Block in the North China Craton subducted under the Nangrim Massif on the Korean Peninsula.

为了进一步了解辽东地区胶辽－冀基带南缘的变质作用演化，对辽河南组的代表性变质岩进行了详细的岩石学和年代学研究。样品的峰值变质阶段（M1）由样品DD24-1中的石榴石-黑云母-斜长石-硅线石-石英-磁铁矿和样品DD24-2中的石榴石-黑云母-斜长石-钛铁矿-石英的矿物组合表示。峰后变质阶段（M2）由堇青石的出现和样品DD24-1中黑云母-堇青石-石榴石-斜长石-K长石-硅线石-石英-磁铁矿-钛铁矿的矿物组合指示。使用伪截面和常规地热气压计进行的PT计算表明，M1，M2和最后逆行阶段（M3）的变质分别发生在865–890°C和6.9–9.2 kbar，840–860°C和5.3–6.2 kbar和570–670°C和3.3–4 kbar。锆石SHRIMP U铅年龄数据表明，DD24-1和DD24-2样品的M1变质分别发生在1867±11 Ma和1866±8 Ma。与先前的研究一起，这项研究证实了南辽河组和吉安组发生了一个低P / T型花岗石相的区域变质事件1.87-1.84 Ga，具有顺时针的PT路径。低P / T型变质与南辽河和吉安组同时发生的碰撞后火成活动一起表明，南辽河和吉安组在1.87–1.84 Ga发生碰撞后活动是由于板块破裂后发生的。碰撞。结合朝鲜半岛南里姆地块普遍存在的碰撞后活动，这项研究表明，华北克拉通的龙岗地块在朝鲜半岛南里姆地块之下俯冲。