『Abstract
　We report new estimates of abundances of rarely analyzed elements (As, B, Be, Bi, Cd, Ge, In, Mo, Sb, Sn, Te, Tl, W) in the upper continental crust based on precise ICP-MS analyses of well-characterized upper crustal samples (shales, pelites, loess, graywackes, granitoids and their composites) from Australia, China, Europe, New Zealand and North American. Obtaining a better understanding of the upper crustal abundance and associated uncertainties of these elements is important in placing better constraints on bulk crust composition and, from that, whole Earth models of element cycling and crust generation. We also present revised abundance estimates of some more commonly analyzed trace elements (Li, Cr, Ni, and Tm) that vary by ＞20％ compared to previous estimates. The new estimates are mainly based on significant (r²＞0.6) inter-element correlations observed in clastic sediments and sedimentary rocks, which yield upper continental crust elemental ratios that are used in conjunction with well-determined abundances for certain key elements to place constraints on the concentrations of the rarely analyzed elements. Using the well-established upper crustal abundances of La (31 ppm), Th (10.5 ppm), Al2O3 (15.40％), K2O (2.80％) and Fe2O3 (5.92％), these ratios led to revised upper crustal abundances of B=47 ppm, Bi=0.23 ppm, Cr=73 ppm, Li=41 ppm, Ni=34 ppm, Sb=0.075, Te=0.027 ppm, Tl=0.53 ppm and W=1.4 ppm. No significant correlations exist between Mo and Cd and other elements in the clastic sediments and sedimentary rocks, probably due to their enrichment in organic carbon. We thus calculate abundances of these elements by assuming the upper continental crust consists of 65％ granitoid rocks plus 35％ clastic sedimentary rocks. The validity of this approach is supported by the similarity of SiO2, Al2O3, La and Th abundances calculated in this way with their upper crustal abundances given in Rudnick and Gao [Rudnick, R., Gao, S., 2003. Composition of the continental crust. In: Rudnick,R.L. (Ed.), The Crust. In: Holland, H.D., Turekian, K.K. (Eds.), Treatise on Geochemistry, vol. 3, Elsevier-Pergamon, Oxford, pp. 1-64]. The upper crustal abundances thus obtained are Mo=0.6 ppm and Cd=0.06 ppm. Our data also suggest a 〜20％ increase of the Tm, Yb and Lu abundances reported in Rudnick and Gao [Rudnick, R., Gao, S., 2003. Composition of the continental crust. In: Rudnick, R.L. (Ed.), The Crust. In: Holland, H.D., Turekian, K.K. (Eds.), Treatise on Geochemistry, vol. 3, Elsevier-Pergamon, Oxford, pp. 1-64.

Keywords: Geochemistry; Composition of the upper continental crust; Trace elements』

1. Introduction
2. Samples of the upper continental crust
3. Analytical methods
　3.1. Instrumentation
　3.2. Reagents
　3.3. Sample digestion
　3.4. Accuracy and precision
4. Discussion
　4.1. Nb, Ta, Zr and Hf
　4.2. Ga and In
　4.3. Sn
　4.4. Rb and Cs
　4.5. Tl
　4.6. Be
　4.7. Ge and W
　4.8. Bi
　4.9. U
　4.10 Transition metals Sc, Co, V, Cr, Ni, Cu and Zn
　4.11 Li
　4.12 B
　4.13 Te
　4.14 Sb and As
　4.15 Mo and Cd
　4.16 Heavy rare earth elements Er, Tm, Yb and Lu
5. Conclusions
Acknowledgments
Appendix A. Supplementary data
References

Table 5 Various estimates of trace element abundances (ppm) of the upper continental crust

Element	1 Shaw et al. (1967,1976)	2 Eade and Fahrig (1973)	3 Condie (1993)	4 Gao et al. (1998)	5 Sims et al. (1990)	6 Plank and Langmuir (1998)	7 Taylor and McLennan (1985,1995)	8 McLennan (2001)	9 Wedepohl (1995)	10 Rudbick and Gao (2003)	11 This study
Li	22			20			20		(22)	21	41
Be	1.3			1.95			3		3.1	2.1	1.9
B	9.2			28			15		17	17	47
Sc	7	12	13.5	15			11	13.6	(7)	14.0	14
V	53	59	86	98			60	107	(53)	97	106
Cr	35	76	112	80			35	85	(35)	92	73
Co	12		18	17			10	17	(12)	17.3	15
Ni	19	19	60	38			20	44	(19)	47	34
Cu	14	26		32			25		(14)	28	27
Zn	52	60		70			71		(52)	67	75
Ga	14			18			17		(14)	17.5	18.6
Ge				1.34			1.6		1.4	1.4	1.3
As				4.4	5.1		1.5		2	4.8	5.7
Rb	110	85	83	82			112		110	84	94
Nb	26		9.8	12		13.7	25	12	(26)	12	11.6
Mo				0.78	1.2		1.5		1.4	1.1	0.6
Cd	0.075			0.079			0.098		0.102	0.09	0.06
In							0.05		0.061	0.056	0.066
Sn				1.73			5.5		2.5	2.1	2.2
Sb				0.3	0.45		0.2		0.31	0.4	0.75
Te											0.027
Cs				3.55		7.3	3.7	4.6	5.8	4.9	4.9
Er							2.3			2.3	2.30
Tm							0.33			0.30	0.37
Yb	1.47		1.91	2.26			2.2		(1.5)	2.0	2.34
Lu	0.233		0.32	0.35			0.32		(0.27)	0.31	0.36
Ta	5.7		0.79	0.74		0.96	2.2	1.0	1.5	0.9	0.92
W				0.91	3.3		2		1.4	1.9	1.4
Tl	0.524			1.55			0.75		0.75	0.9	0.55
Bi	0.035			0.23			0.13		0.123	0.16	0.23
U	2.45	1.5	2.2	1.55			2.8		(2.5)	2.7	2.6
Columns 1-4 represent averages of surface exposures. Columns 5-9 are estimates derived from fine-grain clastic sedimentary rocks and loess. Bracketed data in column 9 are values derived from Shaw et al. (1967,1976).

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