ORIGINAL ARTICLE Effectiveness of rare earth elements constrain on different materials: a case study in central Asia Chaoliu Li • Shichang Kang • Qianggong Zhang • Chhatra Mani Sharma Received: 18 December 2010 / Accepted: 28 January 2012 / Published online: 15 February 2012 Ó Springer-Verlag 2012 Abstract Rare earth elements (REE) have been exten- sively used to indicate for material provenance since they behave conservatively and mainly transport in particulate form during earth surface processes. Nevertheless, the application of REE for material provenance study has to be cautious because grain size and mineral fractionations can alter bulk compositions of weathered sediments. Central Asia is one of the most important dust source regions globally and numerous studies on REE compositions of surface materials have been conducted. In this study, REE compositions of various materials from this area are sum- marized to explore the existing REE-related problems. Overall, chondrite-normalized REE patterns for many surface materials are so uniform that they cannot serve as reliable approaches in tracing material source regions. In contrast, great variations of REE compositions occur among different materials that are derived even from the same parent rock due to influences of grain-size distribu- tions and heavy minerals. For the same reason, small-scale loess around the Tibetan Plateau has different upper con- tinental crust (UCC)-normalized REE patterns compared to those of typical loess. Therefore, great cautions should be made when UCC-normalized REE patterns and REE ratios are utilized to investigate material provenance. Finally, some suggestions are proposed for such studies in future. Keywords Rare earth elements Á Material provenance Á Upper continental crust Á Central Asia Introduction Rare earth elements (REE) are a series of typical immobile elements that do not readily fractionate during earth surface processes (Taylor and McLennan 1985). This set of ele- ments is widely used as robust evidence to determine source regions of dust aerosols (Svensson et al. 2000; Yang et al. 2007a; Zdanowicz et al. 2006; Zhang et al. 2009), loess (Honda et al. 2004; Sun 2002a), fluvial and marine sediments (Nakai et al. 1993; Yang et al. 2002), especially after the publication of a classic book by Taylor and McLennan (1985). The theories proposed in this book provide fundamental principles for subsequent geochemi- cal studies. However, some theories on REE mentioned in the book sometimes are partially understood and misused. Among them the commonly misused two theories are ‘‘there is no significant difference in the REE patterns between the finest fractions ( \ 1 lm) and the silt-sized ( \ 20 lm) fraction (P37)’’ and ‘‘the nature of the Europium (Eu)-anomalies is similar in all of the size fractions con- sidered (P38)’’. Based on these two theories it is sometimes even considered that REE compositions are constant in all size fractions of the same material. Consequently, REE compositions and Eu anomalies were simply compared among different grain sizes in material provenance studies (Chang et al. 2000; Sun et al. 2007; Wu et al. 2009; Yang et al. 2007a), ignoring those cautions noted by the authors in the same book. Many of these cautions are related to the C. Li Á S. Kang (&) Á Q. Zhang Á C. M. Sharma Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, CAS, Beijing 100085, China e-mail: shichang.kang@itpcas.ac.cn S. Kang State Key Laboratory of Cryospheric Sciences, CAS, Lanzhou 730000, China C. M. Sharma Human and Natural Resources Studies Centre, Kathmandu University, P.O. Box 6250, Dhulikhel, Kathmandu, Nepal 123 Environ Earth Sci (2012) 67:1415–1421 DOI 10.1007/s12665-012-1586-2