地质学报2018，Vol.92Issue(4)：687-703,17.
华北克拉通东南缘蚌埠隆起带早白垩世晚期二长花岗岩成因及动力学背景
Originand Dynamics Background of Late Early Cretaceous Monzonite Granite in the Bengbu Uplift, Southeastern Margin of the North China Craton
摘要
Abstract
The Bengbu uplift,located in the southeastern margin of the North China Craton,experienced a more complex evolution process,in company with the collisions and stitching of the Yangtze platform and north China continental block.Authors collected seven samples from monzonite granite intrusions of late Early Cretaceous to conduct field observation and geochronological study.The ages obtained concentrate around 114.6±3.3Ma～121± 1.0Ma.Geochemical data show that the rocks are characterized by Si-and alkalirich,calcium alkaline,weak Al-saturation,relative REE enrichment,weak negative Eu anomaly and no obivious Ce anomaly,distinct depletion of K,P an Ti,and relative enrichment of Rb,Ta,Sr and Nd,suggesting that the source rocks consisting mainly of continental crust experienced anatexis.K2O-Na2O and SiO2-Zr discrimination diagram shows that all points fall into I-type granite area.Epsilon Hf(t) values are all negative with relatively low values of-25.2～-15.61,indicating its crustal origin.Two stages of Hf model age (2.17～2.76 Ga) suggests that the rocks sourced dominantly from Neo-Archean continental crust material.Combined with the formation time of the North China Craton,this study concludes that magma source area was mainly lower crust material under the North China Craton.Crustal thickening and delamination of lower crust and lithosphere caused large-scale magmatic activity.Partial melting of thicken lower crust resulted in rapid uplift of the earth's crust and subsequent stretching.Modifying and recycling of the ancient continental crust material gave a rise to the formation of the monzonitic granite during late Early Cretaceous.关键词
华北克拉通/蚌埠隆起带/二长花岗岩/早白垩世晚期/动力学背景Key words
North China Craton/Bengbu uplift/monzonitic granite/late Early Cretaceous/geodynamic background引用本文复制引用
康丛轩,杨献忠,蔡逸涛,宗雯,黄先觉,孔广林,李朝维..华北克拉通东南缘蚌埠隆起带早白垩世晚期二长花岗岩成因及动力学背景[J].地质学报,2018,92(4):687-703,17.基金项目
本文为安徽省公益性地质调查基金(项目编码:2014-K-5)资助的成果. （项目编码:2014-K-5）
