| Petrogenetic significance of rare-earth element behavior in the basement rocks of southern Obudu Plateau, Bamenda Massif, southeastern Nigeria |
| |
| 作者姓名： | UKAEGBUV.U. EKWUEMEB.N. |
| |
| 作者单位： | [1]DepartmentofGeology,UniversityofPortHarcourt,PortHarcourt,Nigeria [2]DepartmentofGeology,UniversityofCalabar,Calabar,Nigeria. |
| |
| 基金项目： | FundingforthisresearchcamefromSenate/NigeriaUniversitiesCom missionResearchGrantNumberUPH/DVC.AC/11/SD.022/COM.4oftheUniversityofPortHarcourt. |
| |
| 摘 要： | Rock samples representing various igneous and metamorphic rocks of southern Obudu Plateau were analyzed for rare-earth element ( REE ) behavior by ICP-MS. Results of the analyses indicate a range of REE abundances and distinctive patterns from highly fraetionated patterns with negative Eu anomalies in granitic rocks to relatively low abundances and less REE fractionated flat patterns with little Eu anomaly in some paragneisses, schists, enderbites and dolerites to unfractionated patterns with positive Eu anomalies in some paragneisses and charnockites. Over all, there are low to high ∑ REE contents with negative to positive Eu anomalies. The ratios of different parameters, especially La/Yb and Ce/Yb, show behaviors consistent with crustal to mantle derivation. The heterogeneity of REE abundances and REE patterns reflects mantle to crustal petrogenetic variations of different rock suites on the Plateau. The LREE content is higher than the HREE content in the highly differentiated rocks, as evidenced by their La/Yb,Ce/Yb and La/Sm ratios, which are normally higher in residual products than in primary melts. The dominantly intermediate nature of the source rock of the orthogneisses is suggested by the generally low ∑ REE. The granites enriched in LREE and depleted in HREE and some of the charnockites with negative Eu anomalies were probably formed by partial melting and crystallization.
|
| 关 键 词： | 稀土元素 地球化学 丰度 Obudu高原 变质岩 |
| 收稿时间： | 3 July 2008 |
Petrogenetic significance of rareearth element behavior in the basement rocks of southern Obudu Plateau,Bamenda Massif,southeastern Nigeria |
| |
| UKAEGBUV.U. EKWUEMEB.N..Petrogenetic significance of rare-earth element behavior in the basement rocks of southern Obudu Plateau, Bamenda Massif, southeastern Nigeria[J].Chinese Journal of Geochemistry,2005,24(2):129-135. |
| |
| Authors: | V U Ukaegbu B N Ekwueme |
| |
| Institution: | (1) Department of Geology, University of Port Harcourt, Port Harcourt, Nigeria;(2) Department of Geology, University of Calabar, Calabar, Nigeria |
| |
| Abstract: | Rock samples representing various igneous and metamorphic rocks of southern Obudu Plateau were analyzed for rare-earth element (REE) behavior by ICP-MS. Results of the analyses indicate a range of REE abundances and distinctive patterns from highly fractionated patterns with negative Eu anomalies in granitic rocks to relatively low abundances and less REE fractionated flat patterns with little Eu anomaly in some paragneisses, schists, enderbites and dolerites to unfractionated patterns with positive Eu anomalies in some paragneisses and charnockites. Over all, there are low to high ∑REE contents with negative to positive Eu anomalies. The ratios of different parameters, especially La/Yb and Ce/Yb, show behaviors consistent with crustal to mantle derivation. The heterogeneity of REE abundances and REE patterns reflects mantle to crustal petrogenetic variations of different rock suites on the Plateau. The LREE content is higher than the HREE content in the highly differentiated rocks, as evidenced by their La/Yb, Ce/Yb and La/Sm ratios, which are normally higher in residual products than in primary melts. The dominantly intermediate nature of the source rock of the orthogneisses is suggested by the generally low ∑REE . The granites enriched in LREE and depleted in HREE and some of the charnockites with negative Eu anomalies were probably formed by partial melting and crystallization. |
| |
| Keywords: | rare-earth element abundance pattern fractionation petrogenesis |
| 本文献已被 CNKI 维普 万方数据 SpringerLink 等数据库收录！ |
|
