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本文描述了华北地区六个产地的超镁铁质捕掳体,它们均产于新第三纪、第四纪碱性玄武岩中,分布于华北东部郯庐断裂带及其两侧和华北西部近南北向的重力梯级带中。据新变晶大小所估算的应力值,在华北断块西部为250—300巴,华北断块东部为300—600巴。由捕掳体共生矿物组合得出岩石的平衡P-T条件为950°—1160℃及15—25千巴(50—80公里),所代表的古地温曲线具有海洋型地温,并有靠近大陆裂谷区地温曲线的倾向。
This paper describes the ultramafic entrapped bodies in six producing areas in North China. They are all produced in the Neogene and Quaternary alkaline basalts and distributed in the Tanlu fault zone and its two sides in the eastern part of North China and near the western part of North China North-South gravity gradient belt. The stress value estimated from the new metamorphic size is 250-300 bar in the western part of North China and 300-600 bar in the eastern part of North China. The equilibrium PT of the rocks derived from the assemblage of entrapped bodies is 950 ° -1160 ° C and 15-25 kPa (50-80 km). The paleotemperature tem- perature curves represented by these rocks have oceanic geotemperature and are near the continental rift District geothermal curve tendency.