1 Introduction The Cantung W-Cu skarn deposit is located within the Canadian Cordilleran in the Northwest Territories. It is related to an intrusive system that is associated with part of a chain of Middle Cretaceous felsic plutonic suites, which are emplaced into Neoproterozoic rifted margin and Paleozoic passive margin rocks originating from Laurentia (Rasmussen et al., 2011). The Cantung W-Cu skarn is a contact metasomatic hydrothermal system in which a peraluminous biotite monzogranite intruded into Lower Cambrian marbles; this produced a zoned array of anhydrous and hydrous reduced skarn facies (Mathieson and Clark, 1984). Since the opening of the Cantung mine in 1962, an estimated total of 6.21 Mt of ore was extracted by 2009; the average grade is approximately 1.56% WO 3 (Rasmussen et al., 2011). The main tungsten-bearing phase in this calcic skarn is scheelite. Scheelite is known to host considerable REE and Y and its composition has been used to date the timing for formation of scheelite using the Sm-Nd methods (Sylvester and Ghaderi, 1990; Anglin, 1990). Whole-rock lithogeochemical sampling and multielement analysis of the skarn was followed up by detailed petrology, microanalysis (SEM-EDS & SEM- BSE imaging), and then detailed trace element analyses and elemental mapping (LA ICP-MS) of selected scheelite crystals. This was done to ascertain the concentrations of REE in scheelite and study their zoning to better understand the growth of scheelite and the movement of REE in the hydrothermal fluids. The extraction of these rare earth elements present at elevated concentrations in scheelite (such as Y and HREE and possibly Eu) could increase the value of the ore. 2 Lithogeochemistry In order to build a better understanding of the distribution of metals associated with this large high-grade W skarn, 46 samples were taken throughout the mine workings to represent the various facies of the skarn ore. Whole-rock geochemical analyses by fusion ICP-OES and ICP-MS at ACME Labs (Vancouver Canada) suggests that the bulk ore-bearing samples contain elevated rare earth elements values (as much as 114 ppm La, 190 ppm Ce, and 80 ppm Y). The W grade in these samples is such that the gravity concentration process might increase the total amount of rare earth elements in the mineral concentrate to a point that might warrant their extraction. Correlation coefficients (Spearman’s Rank, SRCC, r’) were calculated using the lithogeochemical data to try and ascertain any elemental associations related to the mineralogy associated with scheelite mineralization and it’s associated alteration, as well as get an idea of the elemental enrichments resulting from the mineralization and alteration processes. It appears that W does not correlate well with the rare earths in the lithogeochemical data, phosphorus however does. This is likely because much of the rare earths in these rocks are actually found in apatite rather than scheelite. The correlation coefficient between W and La (0.10), and Y (0.14) are generally below the critical value of 0.30 for the SRCC with 44 degrees of freedom. La, Ce, and Y have correlation coefficients > 0.30 with P, suggesting that much of the REE are in apatite. 3 Scheelite Chemical Systematics The lithogeochemical results were followed up with mineral-chemical analyses on scheelite in attempt to quantify the major element composition of scheelite, as well as the concentration of trace and REE. The SEM-BSE Carlin LENTZ and Chris McFARLANE, 2014. Trace and Rare Earth Element Distribution in Scheelite from the Cantung Tungsten Bearing Skarn Deposit, N.W.T. Canada: a Geometallurgical Analysis with Evidence from SEM and LA ICP-MS Analysis . Acta Geologica Sinica (English Edition), 88(supp. 2): 441-442. Trace and Rare Earth Element Distribution in Scheelite from the Cantung Tungsten Bearing Skarn Deposit, N.W.T. Canada: a Geometallurgical Analysis with Evidence from SEM and LA ICP-MS Analysis Carlin LENTZ and Chris McFARLANE University of New Brunswick, Fredericton, NB, E3B 5A3, Canada Vol. 88 Supp. 2 * Corresponding author. E-mail: carlin.lentz90@gmail.com 441 ACTA GEOLOGICA SINICA (English Edition) http://www.geojournals.cn/dzxben/ch/index.aspx http://mc.manuscriptcentral.com/ags Aug. 2014