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Spectrochemical determination of trace elements in the U.S.G.S. silicate rock standards
Chemical Geology - E l s e v i e r Publishing Company, Amsterdam Printed in The Netherlands
Short Communication S P E C T R O C H E M I C A L D E T E R M I N A T I O N OF T R A C E E L E M E N T S IN THE U.S.G.S. SILICATE R O C K STANDARDS
W.H. BLACKBURN, T.B. GRISWOLD and W.H. DENNEN Cabot Spectrographic Laboratory, Department of Geology, University of Kentucky, Lexington, Ky. (U.S.A.) (Received January 26, 1970) (Resubmitted September 17, 1970) ABSTRACT Blackburn, W.H., Griswold, T.B. and Dennen, W.H., 1971. Spectrochemical determination of trace elements in the U.S.G.S. silicate rock standards. Chem. Geol., 7: 143-147. Spectrographic determinations for twenty trace elements in the six new U.S.G.S. silicate rock standards along with the rock standards G - l , W-l, SR-1, GR and BR are given. Most of the results represent the average of triplicate determinations on each of five splits of the portions of the standards available to the authors. Thus, the preferred values represent, in most cases, the average of fifteen replicate determinations. INTROD UCTION T o c o n t r i b u t e to the e s t a b l i s h m e n t of the s i x U.S.G.S. s i l i c a t e r o c k s a s p r i m a r y s t a n d a r d s a n d to d e v e l o p a n d t e s t a r o u t i n e s p e c t r o g r a p h i c t e c h n i q u e , d e t e r m i n a t i o n s w e r e m a d e for twenty t r a c e e l e m e n t s i n the s i x r o c k s . As a f u r t h e r t e s t of p r e c i s i o n a n d a c c u r a c y of the m e t h o d , the s a m e t e c h n i q u e w a s a p p l i e d to e x i s t i n g r o c k s t a n d a r d s . T h e r e s u l t s r e p o r t e d in t h i s p a p e r w i l l be c o m p a r e d to the p r e f e r r e d v a l u e s g i v e n by F l a n a g a n (1969) and to the r e s u l t s g i v e n in the m o s t r e c e n t c o m p i l a t i o n s for G - l , W - 1 ( F l e i s c h e r , 1969), SR-1 (Sine et a l . , 1969), GR a n d BR (Roubault et a l . , 1968). ANALYTIC TECHNIQUE T h e e m i s s i o n s p e c t r o g r a p h i c t e c h n i q u e for the d e t e r m i n a t i o n of t r a c e e l e m e n t s in s i l i c a t e m a t e r i a l s , a s d e v e l o p e d for u s e in t h i s l a b o r a t o r y , i s a m o d i f i c a t i o n of the m e t h o d s d e s c r i b e d by A h r e n s (1954) a n d Shaw (1960). It should be n o t e d that a p a l l a d i u m i n t e r n a l s t a n d a r d w a s u s e d t h r o u g h o u t t h e wave length r e g i o n 2 , 5 0 0 - 4 , 2 0 0 A with n o a p p a r e n t l o s s of p r e c i s i o n . T h i s is p r o b a b l y due to l e s s e n i n g of m a t r i x and v o l a t i l i z a t i o n e f f e c t s by the d i l u tion t e c h n i q u e e m p l o y e d and the u s e of a gas j e t for a r c s t a b i l i z a t i o n . T h e j e t u s e d is a m o d i f i c a t i o n of the o r i g i n a l Stallwood J e t (Stallwood, 1954; Shaw, 196 0) a n d is fully d e s c r i b e d by D e n n e n a n d B l a c k b u r n (1969). T h e l a c k of an a p p r o p r i a t e Chem. Geol., 7 (1971) 143-147
143
Pd line in the region 4,200-8,600 ~ w a r r a n t s the use of sodium as a variable internal standard for Ba, Li, Rb and Sr. Full details of techniques and data will be provided on request. In o r d e r to evaluate the homogeneity of the six silicate s a m p l e s p r e p a r e d by the U.S.G.S., it is r e c o m m e n d e d that analysts contributing to the p r o g r a m note, along with t h e i r r e s u l t s , the split and position of each of their p a r t i c u l a r portions. This data for the p r e s e n t study is given in Table I. A further test of the homogeneity of our own s a m p l e s was attempted by p e r forming the a n a l y s e s in triplicate on five separate sample weighings. No significant inhomogeneities were found in our p a r t i c u l a r s a m p l e s . TABLE I U.S.G.S. coding with regard to preparation of the rocks of this study U.S.G.S. Standard
Split position
Granite G-2 Granodiorite GSP-1 Andesite AGV-1 Basalt BCR-t Peridotite PCC-1 Dunite DTS-1
110/21 70/12 96/31 13/25 30/2 35/15
RESULTS Table H p r e s e n t s the grand a v e r a g e s of all d e t e r m i n a t i o n s for each element. Also given in this table a r e the statistical data for the a n a l y s e s along with the p r e s e n t p r e f e r r e d values for these r o c k s taken f r o m Flanagan (1969). A f u r t h e r t e s t of the p r e c i s i o n and a c c u r a c y of the method is obtainable from the data given in Table HI. H e r e , values r e s u l t i n g from t r a c e element d e t e r m i n a t i o n s in the standard r o c k s G - I , W - I , SR-1, GR and BR a r e presented. Statistical data and p r e f e r r e d values for these r o c k s a r e p r e s e n t e d w h e r e v e r possible. E l e m e n t s looked for, but found below the sensitivity of the method a r e , along with t h e i r sensitivities, Bi (1 p.p.m.), Ge (1 p.p.m.), In (0.5 p.p.m.), Cs (3 p.p.m.), T1 (2 p.p.m.). ACKNOWLEDGEME NTS The a u t h o r s gratefully acknowledge the support of National Science Foundation Grants GA-1353 and GA-1397.
144
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REFERENCES Ahrens, L.H., 1954. Quantitative Spectrochemical Analysis of Silicates, Pergamon, London, 122 pp. Dennen, W.H. and Blackburn, W.H., 1969. Simple jet for emission spectrography. AppL Speetroscropy, 23: 72. Flanagan, F.J., 1969. U.S. Geological Survey standards, II. F i r s t compilation of data for the new U.S.G.S. rocks. Geochim. Cosmochim. Acta, 33: 81-120. Fleischer, M., 1969. U.S. Geological Survey standards, I. Additional data on rocks G-1 and W-l, 1965-1967. Geochim. Cosmoctlim. Acta, 33: 65-79. Roubault, M., de la Roche, H. and Govindaragu, K., 1968. Rapport sur les standards g~ochimiques. Sci. T e r r e , 13 (4): 379-404. Shaw, D.M., 1960. Speetrochemieal analysis of silicates using the Stallwood Jet. Can. Mineralogist, 6: 467-482. Sine, N.M., Taylor, W.O., Webber, G.R. and Lewis, C.L., 1969. Third report of the analytical data for the CAAS sulphide ore and syenite rock standards. Geochim. Cosmochim. Acta, 33: 121-131. Stallwood, B.J., 1954. A i r - c o o l e d electrodes for the spectrochemical analysis of powders. J. Opt. Soc. Am., 44: 171-176.
Chem. Geol., 7 (1971) 143-147
147
Short Communication S P E C T R O C H E M I C A L D E T E R M I N A T I O N OF T R A C E E L E M E N T S IN THE U.S.G.S. SILICATE R O C K STANDARDS
W.H. BLACKBURN, T.B. GRISWOLD and W.H. DENNEN Cabot Spectrographic Laboratory, Department of Geology, University of Kentucky, Lexington, Ky. (U.S.A.) (Received January 26, 1970) (Resubmitted September 17, 1970) ABSTRACT Blackburn, W.H., Griswold, T.B. and Dennen, W.H., 1971. Spectrochemical determination of trace elements in the U.S.G.S. silicate rock standards. Chem. Geol., 7: 143-147. Spectrographic determinations for twenty trace elements in the six new U.S.G.S. silicate rock standards along with the rock standards G - l , W-l, SR-1, GR and BR are given. Most of the results represent the average of triplicate determinations on each of five splits of the portions of the standards available to the authors. Thus, the preferred values represent, in most cases, the average of fifteen replicate determinations. INTROD UCTION T o c o n t r i b u t e to the e s t a b l i s h m e n t of the s i x U.S.G.S. s i l i c a t e r o c k s a s p r i m a r y s t a n d a r d s a n d to d e v e l o p a n d t e s t a r o u t i n e s p e c t r o g r a p h i c t e c h n i q u e , d e t e r m i n a t i o n s w e r e m a d e for twenty t r a c e e l e m e n t s i n the s i x r o c k s . As a f u r t h e r t e s t of p r e c i s i o n a n d a c c u r a c y of the m e t h o d , the s a m e t e c h n i q u e w a s a p p l i e d to e x i s t i n g r o c k s t a n d a r d s . T h e r e s u l t s r e p o r t e d in t h i s p a p e r w i l l be c o m p a r e d to the p r e f e r r e d v a l u e s g i v e n by F l a n a g a n (1969) and to the r e s u l t s g i v e n in the m o s t r e c e n t c o m p i l a t i o n s for G - l , W - 1 ( F l e i s c h e r , 1969), SR-1 (Sine et a l . , 1969), GR a n d BR (Roubault et a l . , 1968). ANALYTIC TECHNIQUE T h e e m i s s i o n s p e c t r o g r a p h i c t e c h n i q u e for the d e t e r m i n a t i o n of t r a c e e l e m e n t s in s i l i c a t e m a t e r i a l s , a s d e v e l o p e d for u s e in t h i s l a b o r a t o r y , i s a m o d i f i c a t i o n of the m e t h o d s d e s c r i b e d by A h r e n s (1954) a n d Shaw (1960). It should be n o t e d that a p a l l a d i u m i n t e r n a l s t a n d a r d w a s u s e d t h r o u g h o u t t h e wave length r e g i o n 2 , 5 0 0 - 4 , 2 0 0 A with n o a p p a r e n t l o s s of p r e c i s i o n . T h i s is p r o b a b l y due to l e s s e n i n g of m a t r i x and v o l a t i l i z a t i o n e f f e c t s by the d i l u tion t e c h n i q u e e m p l o y e d and the u s e of a gas j e t for a r c s t a b i l i z a t i o n . T h e j e t u s e d is a m o d i f i c a t i o n of the o r i g i n a l Stallwood J e t (Stallwood, 1954; Shaw, 196 0) a n d is fully d e s c r i b e d by D e n n e n a n d B l a c k b u r n (1969). T h e l a c k of an a p p r o p r i a t e Chem. Geol., 7 (1971) 143-147
143
Pd line in the region 4,200-8,600 ~ w a r r a n t s the use of sodium as a variable internal standard for Ba, Li, Rb and Sr. Full details of techniques and data will be provided on request. In o r d e r to evaluate the homogeneity of the six silicate s a m p l e s p r e p a r e d by the U.S.G.S., it is r e c o m m e n d e d that analysts contributing to the p r o g r a m note, along with t h e i r r e s u l t s , the split and position of each of their p a r t i c u l a r portions. This data for the p r e s e n t study is given in Table I. A further test of the homogeneity of our own s a m p l e s was attempted by p e r forming the a n a l y s e s in triplicate on five separate sample weighings. No significant inhomogeneities were found in our p a r t i c u l a r s a m p l e s . TABLE I U.S.G.S. coding with regard to preparation of the rocks of this study U.S.G.S. Standard
Split position
Granite G-2 Granodiorite GSP-1 Andesite AGV-1 Basalt BCR-t Peridotite PCC-1 Dunite DTS-1
110/21 70/12 96/31 13/25 30/2 35/15
RESULTS Table H p r e s e n t s the grand a v e r a g e s of all d e t e r m i n a t i o n s for each element. Also given in this table a r e the statistical data for the a n a l y s e s along with the p r e s e n t p r e f e r r e d values for these r o c k s taken f r o m Flanagan (1969). A f u r t h e r t e s t of the p r e c i s i o n and a c c u r a c y of the method is obtainable from the data given in Table HI. H e r e , values r e s u l t i n g from t r a c e element d e t e r m i n a t i o n s in the standard r o c k s G - I , W - I , SR-1, GR and BR a r e presented. Statistical data and p r e f e r r e d values for these r o c k s a r e p r e s e n t e d w h e r e v e r possible. E l e m e n t s looked for, but found below the sensitivity of the method a r e , along with t h e i r sensitivities, Bi (1 p.p.m.), Ge (1 p.p.m.), In (0.5 p.p.m.), Cs (3 p.p.m.), T1 (2 p.p.m.). ACKNOWLEDGEME NTS The a u t h o r s gratefully acknowledge the support of National Science Foundation Grants GA-1353 and GA-1397.
144
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Chem. Geol., 7 (1971) 143-147
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REFERENCES Ahrens, L.H., 1954. Quantitative Spectrochemical Analysis of Silicates, Pergamon, London, 122 pp. Dennen, W.H. and Blackburn, W.H., 1969. Simple jet for emission spectrography. AppL Speetroscropy, 23: 72. Flanagan, F.J., 1969. U.S. Geological Survey standards, II. F i r s t compilation of data for the new U.S.G.S. rocks. Geochim. Cosmochim. Acta, 33: 81-120. Fleischer, M., 1969. U.S. Geological Survey standards, I. Additional data on rocks G-1 and W-l, 1965-1967. Geochim. Cosmoctlim. Acta, 33: 65-79. Roubault, M., de la Roche, H. and Govindaragu, K., 1968. Rapport sur les standards g~ochimiques. Sci. T e r r e , 13 (4): 379-404. Shaw, D.M., 1960. Speetrochemieal analysis of silicates using the Stallwood Jet. Can. Mineralogist, 6: 467-482. Sine, N.M., Taylor, W.O., Webber, G.R. and Lewis, C.L., 1969. Third report of the analytical data for the CAAS sulphide ore and syenite rock standards. Geochim. Cosmochim. Acta, 33: 121-131. Stallwood, B.J., 1954. A i r - c o o l e d electrodes for the spectrochemical analysis of powders. J. Opt. Soc. Am., 44: 171-176.
Chem. Geol., 7 (1971) 143-147
147