CAJ | 학술논문

对33件采自东太平洋海隆(EPR)13°N附近的玄武岩和火山玻璃样品进行了微量元素分析,以探讨该区域玄武岩的演化过程和物质来源。测试分析结果显示所有样品的微量元素含量比值m(Tb)/m(Lu)(1.74~2.03), m(Sm)/m(Nd)(0.29~0.35)和m(Nd)/m(Y)(0.32~0.48)存在不能忽略的变化,表明它们可能受到了非均一质地幔来源的影响。m(La)/m(Nb), m(La)/m(Sm)和m(La)的线性相关性辨别结果,以及稀土元素分布型式图表现的元素分布特征等均表明东太平洋海隆13°N 附近的洋中脊玄武岩可能来自不同的端元组分,也证明研究区域内的玄武岩除 N-MORB(常规型 MORB)外,还有 E-MORB(富集型MORB)。此外,玄武岩m(Ce)/m(Pb)和m(Ce), m(Nb)/m(U)和m(Nb),以及m(Nb)/m(La)和m(La)线性相关性,均显示了这些微量元素比值和微量元素含量的正相关趋势,这可能与双组分地幔熔融有关。m(Nb)/m(Th)和 m(Th)线性相关性显示出负相关,显示该区域玄武岩的地幔来源组成可能受到了富集组分的影响。分析显示,样品的Nb*值均大于1,而大部分样品的Ta*值大于1,这表示大部分玄武岩的来源很可能是从俯冲区域循环的物质。
대33건채자동태평양해륭(EPR)13°N부근적현무암화화산파리양품진행료미량원소분석,이탐토해구역현무암적연화과정화물질래원。측시분석결과현시소유양품적미량원소함량비치m(Tb)/m(Lu)(1.74~2.03), m(Sm)/m(Nd)(0.29~0.35)화m(Nd)/m(Y)(0.32~0.48)존재불능홀략적변화,표명타문가능수도료비균일질지만래원적영향。m(La)/m(Nb), m(La)/m(Sm)화m(La)적선성상관성변별결과,이급희토원소분포형식도표현적원소분포특정등균표명동태평양해륭13°N 부근적양중척현무암가능래자불동적단원조분,야증명연구구역내적현무암제 N-MORB(상규형 MORB)외,환유 E-MORB(부집형MORB)。차외,현무암m(Ce)/m(Pb)화m(Ce), m(Nb)/m(U)화m(Nb),이급m(Nb)/m(La)화m(La)선성상관성,균현시료저사미량원소비치화미량원소함량적정상관추세,저가능여쌍조분지만용융유관。m(Nb)/m(Th)화 m(Th)선성상관성현시출부상관,현시해구역현무암적지만래원조성가능수도료부집조분적영향。분석현시,양품적Nb*치균대우1,이대부분양품적Ta*치대우1,저표시대부분현무암적래원흔가능시종부충구역순배적물질。
In this study 33 samples including basalts and glass near the East Pacific Rise (EPR) 13°N were analyzed to investigate the evolutionary process and material sources of basalts in this area. The trace elements ratios in-cluding m(Tb)/m(Lu) (1.74~2.03), m(Sm)/m(Nd) (0.29~0.35) and m(Nd)/m(Y) (0.32~0.48) in these samples show that the variations are limited but could not be ignored. It implies these basalts maybe influenced by heterogeneous mantle source. The trace elements ratios m(La)/m(Nb), the linear correlation plot of trace elements ratios m(La)/m(Sm) versus m(La) and REE distribution patterns of chondrite-nomalized basalt samples all show that MORB near EPR 13°N may have different end-members, demonstrating that the basalts near EPR 13°N include N-MORB and E-MORB. Meanwhile, the linear correlation plot of trace elements ratios m(Ce)/m(Pb) versus m(Ce), m(Nb)/m(U) versus m(Nb) and m(Nb)/m(La) versus m(La) all display positive trends. It means they have relation-ship with two end-members mantle melting. Linear correlation plot of trace elements ratios m(Nb)/m(Th) versus m(Th) displays negative trend, which implies there are enriched components involving in mantle source of basalts near EPR 13°N. The values of Nb*of all samples and Ta*of some samples are higer than 1, which demonstrate that mantle source of most MORBs are materials from subduction area.