河北地质大学学报2025，Vol.48Issue(3)：1-9,9.DOI:10.13937/j.cnki.hbdzdxxb.2025.03.001
冀东洒河桥构造带泥质麻粒岩变质作用及锆石年代学研究
Metamorphism and Zircon U-Pb Geochronology of Pelitic Granulites from the Saheqiao Linear-Structural Belt of Eastern Hebei Province
摘要
Abstract
The eastern Hebei region is located in the northwest of the Longgang Block of the North China Craton.Previous studies have conducted extensive research on Early Precambrian rocks in this region,whereas research on the metamorphism of pelitic granulites from the Saheqiao linear-structural belt is relatively limited.This study selects representative pelitic granulite sample(JD1416)and conducts systematic investigations in petrology,major element geochemistry,zircon U-Pb geochronology,and metamorphic phase equilibrium modeling.The mineral assemblage of pelitic granulites is primarily composed of garnet,biotite,plagioclase,K-feldspar,and quartz.Biotite commonly surrounds or crosscuts garnet,indicating that it formed later than garnet.Single-mineral electron microprobe analysis reveals that garnet exhibits zoning characteristics with a decrease in pyrope content from the core to the rim and an increase in grossular content.Plagioclase is predominantly andesine in composition,showing no significant compositional zoning.Phase equilibrium modeling results show that the solidus assemblage of pelitic granulites constrains metamorphic conditions of 9.70 kbar/～850℃,consistent with traditional geothermobarometric estimates(8.3～10.7 kbar/830～899℃).The peak metamorphic assemblage,devoid of biotite,defines peak conditions of 9.86 kbar/～980℃,collectively indicating a counterclockwise P-T evolution path.Zircon U-Pb dating suggests that the protolith of the pelitic granulites was deposited at～2.50 Ga,with granulite-facies metamorphism occurring at 2.46 Ga.The Saheqiao linear tectonic zone in eastern Hebei province was likely controlled predominantly by a vertical tectonic regime during the Archean.关键词
冀东地区/泥质麻粒岩/变质作用/锆石U-Pb定年/构造体制Key words
eastern Hebei province/pelitic granulite/metamorphism/zircon U-Pb dating/tectonic regime分类
地质学引用本文复制引用
谢天鸽,祖大吉,段站站..冀东洒河桥构造带泥质麻粒岩变质作用及锆石年代学研究[J].河北地质大学学报,2025,48(3):1-9,9.基金项目
河北省自然科学基金(D2024403070) （D2024403070）
河北地质大学博士科研启动基金(BQ2024012) （BQ2024012）
