欢迎您！东篱公司
退出
-
申报数据库
-
立项数据库
-
成果数据库
-
项目获奖数据库
中文摘要：
北京西山地区出露的早白垩世阳坊岩体主要由二长花岗岩组成,含少量石英二长岩、白岗岩以及闪长质包体。本文首次报道了阳坊岩体的主量元素和微量元素高精度分析测试结果。黑云母二长花岗岩是典型的高钾钙碱性花岗岩;具有富集Rb、Ba、LREE等强不相容元素,Th、U、Nb、Ta相对LREE亏损,负Eu异常较弱的元素地球化学特征。石英二长岩具有高钾、相对高碱、富镁贫铁、富集Rb、Ba、LREE、Sr等强不相容元素,Sr/Y比值高,Th、U、Nb、Ta相对LREE亏损,Eu异常不明显的特点,具有类似于高Sr低Y型中酸性火成岩（adakite）的元素地球化学特征。白岗岩具有明显亏损Sr、Ba、REE尤其是MREE,具明显负Eu异常的地球化学特征。闪长质包体MgO含量和Mg#值较高,具有富集K、Rb、Ba、LREE、Sr等强不相容元素,Sr/Y比值高,Th、U、Nb、Ta相对LREE亏损,无Eu异常的特点,与玻基方辉安山岩的地球化学特征相近似,属于典型的钾玄岩系列岩石。阳坊岩体的闪长质包体起源于交代岩石圈地幔的部分熔融,石英二长岩是幔源岩浆与下地壳岩石相互作用的产物,黑云母二长花岗岩形成于下地壳富钾基性岩的部分熔融过程,而白岗岩是上地壳岩石部分熔融的产物;表明燕山西段在早白垩世晚期具有高地温梯度。地质证据和岩石化学、微量元素判别图解均显示阳坊岩体形成于造山带崩塌阶段。
英文摘要：
The Yangfang Pluton exposed in Western Hills of Beijing is dominantly composed of biotite monzogranite,and much less quartz monzonite,alaskite and dioritic enclaves. The high-precise analysis of major and trace elements for these rocks are firstly reported by this study. The biotite monzogranite is a typical high-potassic calc-alkaline granite,and has the characteristics of Rb,Ba,and LREE enrichment,depletion of Th,U,Nb,Ta relative to LREE,and weak negative Eu anomaly. The quartz monzodiorite is high potassic and total alkali,magnesium enrichment and iron poor characteristics,and exhibits enrichment of Rb,Ba,LREE and Sr,as well as high Sr/Y ratio,but depletion of Th,U,Nb,Ta relative to LREE,and no siginificant Eu anomaly. So the quartz monzodiorite is similar to adakite （high Sr low Y type intermediate and acid igneous rocks） in geochemistry. The alaskite has obvious depletion of Sr,Ba,and REE （especially MREE）,and negative Eu anomaly. The dioritic enclave is high in magnesium content,Mg# value and Sr/Y ratio,and enriches K,Rb,Ba,LREE,and Sr,but deplets Th,U,Nb,Ta relative to LREE. It does not show any Eu anomaly. The geochemistry of diorite is the same as that of sanukite,and belongs to typical shoshonitic series. The diorite of the Yangfang Pluton was originated by partial melting of metasomatic lithospheric mantle; and the quartz monzonite is the product of mantle-derived magma and lower crust interaction. Meanwhile,the biotite monzogranite and alaskite came from the partial melting of K-rich mafic rocks in the lower crust and upper crustal rocks,respectively. These petrogenetic models imply a very high thermal gradient underneath the western segment of Yanshan orogenic belt during the late stage of Early Creataceous. Geological evidence and wholerock chemistry as well as geochemical discrimination diagrams indicate that the Yangfang Pluton formed during the collapse stage of orogenic evolution.
同期刊论文项目
同项目期刊论文
Style of deep faulting and its control on the Paleogene basin evolved into the western Huimin depres
P-T paths derived from garnet growth zoning in the Danba domal metamorphic terrain, Sichuan Province
Early Cretaceous extensional structures in the Liaodong Peninsula: structural associations, geochron
Geology of the Sandaowanzi telluride gold deposit of the northern Great Xing'an Range, NE China: Geo
Zircon SHRIMP U-Pb age of Yinmawanshan and Zhaofang pluton in South Liaoning metamorphic core comple
Formation and timing of the extensional ductile shear zones in Yiwulü mountain area, Western Liaonin
New Geochronological Data from the Paleozoic and Mesozoic Nappe Structures, Igneous Rocks, and Molyb
期刊信息
位置：