Age and geochemistry of the granitoid from the Lunte area,Northeastern Zambia:Implications for magmatism of the Columbia supercontinent  

作　　者：Hong-wei Sun Jun-ping Ren Jie Wang A-lei Gu Xing-yuan Wu Fu-qing He Li-bo Zuo Chipilauka Mukofu Alphet Phaskani Dokowe Ezekiah Chikambwe Zi-jiang Liu Shi Xing 

机构地区：[1]School of Earth Science and Resources,China University of Geosciences(Beijing),Beijing 100083,China [2]Tianjin Center,China Geological Survey,Tianjin 300170,China [3]Geological Survey Department of Zambia,Lusaka P.O.Box.50135,Zambia [4]No.5 Geological Brigade,Hebei Bureau of Geology and Mineral Resources Exploration,Tangshan 063000,China

出　　处：《China Geology》2021年第4期658-672,共15页中国地质（英文）

基　　金：This study was jointly funded by projects of the Ministry of Commerce([2015]352 and[2012]558);the projects of the China Geological Survey(DD20201150 and 1212011220910)。

摘　　要：The Paleoproterozoic tectonic evolution of the Bangweulu Block has long been controversial.Paleoproterozoic granites consisting of the basement complex of the Bangweulu Block are widely exposed in northeastern Zambia,and they are the critical media for studying the tectonic evolution of the Bangweulu Block.This study systematically investigated the petrography,zircon U-Pb chronology,and petrogeochemistry of the granitoid extensively exposed in the Lunte area,northeastern Zambia.The results show that the granitoid in the area formed during 2051±13-2009±20 Ma as a result of Paleoproterozoic magmatic events.Geochemical data show that the granites in the area mainly include syenogranites and monzogranites of high-K calc-alkaline series and are characterized by high SiO2 content(72.68%‒73.78%)and K_(2)O/Na_(2)O ratio(1.82‒2.29).The presence of garnets,the high aluminum saturation index(A/CNK is 1.13‒1.21),and the 1.27%‒1.95%of corundum molecules jointly indicate that granites in the Lunte area are S-type granites.Rare earth elements in all samples show a rightward inclination and noticeably negative Eu-anomalies(δEu=0.16‒0.40)and are relatively rich in light rare earth elements.Furthermore,the granites are rich in large ion lithophile elements such as Rb,Th,U,and K and are depleted in Ba,Sr,and high field strength elements such as Ta and Nb.In addition,they bear low contents of Cr(6.31×10^(−6)‒10.8×10^(−6)),Ni(2.87×10^(−6)‒4.76×10^(−6)),and Co(2.62×10^(−6)‒3.96×10^(−6)).These data lead to the conclusion that the source rocks are meta-sedimentary rocks.Combining the above results and the study of regional tectonic evolution,the authors suggest that granitoid in the Lunte area were formed in a tectonic environment corresponding to the collision between the Tanzania Craton and the Bangweulu Block.The magmatic activities in this period may be related to the assembly of the Columbia supercontinent.

关 键 词：PALEOPROTEROZOIC S-type granite Bangweulu Block Geological survey engineering Lunte area Northeastern Zambia 

分 类 号：P548[天文地球—构造地质学] P588.121[天文地球—地质学]