由于高场强元素(HFSEs:Ti, Nb, Ta, Zr, Hf和W等)与HF有良好的亲和性,因此采用AG1-X8强阴离子树脂及HF淋洗可以实现地质样品中Ti、Nb、Ta、Zr、Hf和W等高场强元素与Ca、Cr、Mo和V等基体元素的分离;再利用Ln特效树脂可以分离Ti与其他的HF...由于高场强元素(HFSEs:Ti, Nb, Ta, Zr, Hf和W等)与HF有良好的亲和性,因此采用AG1-X8强阴离子树脂及HF淋洗可以实现地质样品中Ti、Nb、Ta、Zr、Hf和W等高场强元素与Ca、Cr、Mo和V等基体元素的分离;再利用Ln特效树脂可以分离Ti与其他的HFSEs,最后通过AG1-X8强阴离子树脂及HF淋洗可进一步对Ti与残留的Ca、Mg等进行分离,从而实现地质样品中Ti与基体元素的最大程度分离,并且可以获得近100%的Ti回收率。分离好的Ti溶液在多接收电感耦合等离子质谱(MC-ICPMS)上采用标准-样品-标准(SSB)的方法测量Ti同位素比值。利用样品相对于前后测量标准(NIST 3162a Ti solution)的万分偏差,获得地质标准样品相对于NIST 3162a的钛同位素组成(ε49Ti)。玄武岩标准物质BHVO-2的ε49Ti的外部精度可达到0.5ε,此结果与双稀释获得的精度相当。利用上述方法我们对一些地质标准物质的钛同位素组成进行了高精度的测试,结果显示地幔玄武岩具有较为均一的钛同位素组成,而较为演化的花岗岩钛同位素组成偏高,不同表生成因的锰结核与沉积物样品的钛同位素组成也有差异,但均介于地幔玄武岩与花岗岩之间。由此可见,不同地质过程会产生明显的钛同位素的分馏,这为我们利用钛同位素组成示踪不同地质过程的作用提供了可能。展开更多
1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its...1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its following properties:(1)Hf-W fractionation commonly occurs during metal-silicate differentiation;(2)Both Hf and W are highly refractory elements,therefore most bulk展开更多
The precision and accuracy of Nd isotope analysis using multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) is verified through repeated measurements of standard reference materials of JMC Nd2O3 and...The precision and accuracy of Nd isotope analysis using multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) is verified through repeated measurements of standard reference materials of JMC Nd2O3 and GBW04419. A mixed solution of Nd separated from hundreds of geological samples is measured for 143Nd/144Nd ratio, which produces excellent long-term repeatability. This solution, named as CAGS-Nd-1, can be used as an in-house reference material for monitoring instrument stability during Nd isotope measurements.展开更多
文摘由于高场强元素(HFSEs:Ti, Nb, Ta, Zr, Hf和W等)与HF有良好的亲和性,因此采用AG1-X8强阴离子树脂及HF淋洗可以实现地质样品中Ti、Nb、Ta、Zr、Hf和W等高场强元素与Ca、Cr、Mo和V等基体元素的分离;再利用Ln特效树脂可以分离Ti与其他的HFSEs,最后通过AG1-X8强阴离子树脂及HF淋洗可进一步对Ti与残留的Ca、Mg等进行分离,从而实现地质样品中Ti与基体元素的最大程度分离,并且可以获得近100%的Ti回收率。分离好的Ti溶液在多接收电感耦合等离子质谱(MC-ICPMS)上采用标准-样品-标准(SSB)的方法测量Ti同位素比值。利用样品相对于前后测量标准(NIST 3162a Ti solution)的万分偏差,获得地质标准样品相对于NIST 3162a的钛同位素组成(ε49Ti)。玄武岩标准物质BHVO-2的ε49Ti的外部精度可达到0.5ε,此结果与双稀释获得的精度相当。利用上述方法我们对一些地质标准物质的钛同位素组成进行了高精度的测试,结果显示地幔玄武岩具有较为均一的钛同位素组成,而较为演化的花岗岩钛同位素组成偏高,不同表生成因的锰结核与沉积物样品的钛同位素组成也有差异,但均介于地幔玄武岩与花岗岩之间。由此可见,不同地质过程会产生明显的钛同位素的分馏,这为我们利用钛同位素组成示踪不同地质过程的作用提供了可能。
基金supported by funds from the National Natural Science Foundation of China (No. 41521062, 41490631)
文摘1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its following properties:(1)Hf-W fractionation commonly occurs during metal-silicate differentiation;(2)Both Hf and W are highly refractory elements,therefore most bulk
文摘The precision and accuracy of Nd isotope analysis using multicollector-inductively coupled plasma mass spectrometry (MC-ICPMS) is verified through repeated measurements of standard reference materials of JMC Nd2O3 and GBW04419. A mixed solution of Nd separated from hundreds of geological samples is measured for 143Nd/144Nd ratio, which produces excellent long-term repeatability. This solution, named as CAGS-Nd-1, can be used as an in-house reference material for monitoring instrument stability during Nd isotope measurements.
