广东惠州燕山期以来地质构造演化:对华南构造的新启示

为揭示广东惠州燕山期以来的地质构造演化，以惠州石坝-黄沙洞地区为例，并综合基础地质调查、大地电磁学、岩石地球化学、年代学等方法来分析研究.大地电磁结果显示研究区深部存在连为一体厚超5 km的燕山期花岗岩体岩床，并被新生代断裂切割；丹霞组底砾岩矿物磨圆较差显示出近源沉积特征；谐和年龄及年龄谱图揭示底砾岩年龄约160 Ma；具有与研究区>150 Ma的花岗岩的稀土元素配分模式图和蛛网图显示底砾岩为燕山期花岗岩体剥蚀产物.在中国华南大陆及邻区构造演化基础之上，建立了研究区自燕山期以来地质历史演化概念模型.燕山期超大规模的岩体侵位造成地壳抬升，先前沉积地层长期遭受剥蚀，致使侵位在古生代、中生代地层中的花岗岩暴露并被剥蚀.剥蚀产物形成丹霞组地层.新生代印度欧亚板块碰撞产生超大规模的粤桂剪切作用和菲律宾板块北漂，形成了河源深断裂带、紫金-博罗断裂和莲花山断裂带等一系列深大断裂，并切穿燕山期花岗岩岩体.多期次活动共同塑造了现今研究区地形. 

Geological Evolution since the Yanshanian in Huizhou,Guangdong Province:New Implications for the Tectonics of South China

Based on synthesizes basic Geological Survey,magnetotellurics,lithogeochemistry,and chronology,a case study of the Shiba-Huangshadong area in Huizhou was settled to reveal the evolution of geological tectonics since the Yanshanian(Jurassic and Cretaceous era)in Huizhou,Guangdong.The magnetotelluric data display that there are present the subterrane an bedrock of Yanshanian granite intrusions with a thickness of more than 5 km,and the graniteis sliced by the Cenozoic faults.The basal conglomerate minerals in the Danxia Formation have edges and corners,which show near-source sedimentary characteristics.The harmonic age and age spectrum show that the age of basal conglomerate is about 160 Ma.The REE pattern and spider diagram of granites in the study area with age more than 150 Ma indicate that the basal conglomerate is the product of denudation of Yanshanian granite.Based on the tectonic evolution of South China and its adjacent areas,we have established a conceptual model of geological evolution of the study area since the Yanshanian.The emplacement of the voluminous Yanshanian granite resulted in the uplift of the crust.The previously deposited strata suffered from long-term denudation,which caused the expose and denudation of granite that in the Paleozoic and Mesozoic strata.Combined with the Cenozoic large-scale Yue-Gui shearing caused by the collision of India-Eurasia plate and the northward drift of Philippine Plate,forming a series of deep-seated faults,for example,the Heyuan fault,the Zijin-Boluo fault,and the Lianhuashan fault.These faults are all cutting through the Yanshanian granite body.The current topography of the study area has been shaped by multiple activities.