地质力学学报2025，Vol.31Issue(4)：638-656,19.DOI:10.12090/j.issn.1006-6616.2025043
鲁西徂徕山地区地壳深熔-韧性变形叠加:对华北克拉通东部新太古代构造样式的约束
Crustal anatexis and ductile superimposition in the Culai Mountain region,western Shandong Province:Constraints on the Neoarchean tectonic framework of the eastern North China Craton
摘要
Abstract
[Objective]Western Shandong is located in the core area of the eastern North China Craton and represents a typical Archean basement exposure.It extends as an overall NW-SE trending linear belt.This area preserves not only multiple phases of magmatic records spanning the early to late Neoarchean but also abundant anatectic-rheological structures overprinted by ductile deformation fabrics.These features are of great significance for understanding the Neoarchean tectonic evolution of the North China Craton.The Culai Mountain region is one of the most promising areas for such geological studies.Situated in the core of the tectonic belt(Belt B)of western Shandong,it is characterized by well-developed anatexis and ductile deformation.This makes it an ideal location for investigating the spatial and temporal relationships between crustal anatexis and ductile deformation.[Methods]In this study,we selected a representative migmatite outcrop at the Huangshiya Village and conducted systematic field structural analyses,petrographic observations,and LA-ICP-MS zircon U-Pb geochronology.[Results]Field observations show that the structural lineaments in this region exhibit an overall NW-SE orientation.Numerous felsic melts developed within the amphibolites,mainly as bands along the foliation,with a few occurring in a network-like or disseminated pattern.Flow folds are well-developed.Petrographic observations demonstrate that quartz grains are distributed along the irregular,corroded boundaries of K-feldspar and plagioclase,containing small melt pockets,bead-like quartzs,and melt films.These features collectively indicate intense anatexis in the region.The newly generated melts reduced the overall rock strength,making it more susceptible to subsequent ductile deformation.Concurrently,NE-SW-oriented horizontal compressive stress further promoted NW-SE regional extension,consistent with the nearly vertical foliation and sub-horizontal mineral stretching lineations observed in the amphibolite.This suggests a deformation regime dominated by near-oblate strain.To constrain the timing of the regional deformation,we conducted LA-ICP-MS zircon U-Pb dating on representative pre-,syn-,and post-tectonic samples of the area.The results indicate that the residual amphibolite records a melt crystallization age of～2503 Ma,representing the timing of the regional anatexis event.The syn-tectonic monzogranite yields a crystallization age of～2497 Ma,reflecting a syn-tectonic magmatic event,while the undeformed pegmatite veins formed at～2465 Ma,bracketing the regional ductile deformation at 2497-2465 Ma.[Conclusion]In summary,the western Shandong region experienced intense anatexis in the late Neoarchean,which was rapidly overprinted by near-oblate strain-dominated shortening deformation under NE-SW-oriented horizontal compressive stress.The anatexis further facilitated the development of NW-SE-directed ductile deformation.The superimposition of these two events ultimately shaped the structural pattern of the Neoarchean crust of the western Shandong region.[Significance]This study provides new constraints that improve the understanding of the Neoarchean tectonic framework and structural patterns of the western Shandong region.关键词
华北克拉通/鲁西/徂徕山/新太古代晚期/深熔作用/韧性变形Key words
North China Craton/western Shandong/Culai Mountain/Late Neoarchean/anatexis/ductile deformation分类
天文与地球科学引用本文复制引用
唐巧婷,张健,张书慧,尹常青,吴启航,赵辰,何明涛,黄葳..鲁西徂徕山地区地壳深熔-韧性变形叠加:对华北克拉通东部新太古代构造样式的约束[J].地质力学学报,2025,31(4):638-656,19.基金项目
国家自然科学基金(42025204,42302221) This research is financially supported by the National Natural Science Foundation of China(Grant Nos.42025204 and 42302221). （42025204,42302221）
