Rare metal indicator minerals in bedrock and till at the Strange Lake peralkaline complex, Quebec and Labrador, Canada

Abstract

A study of rare metal indicator minerals and glacial dispersal was carried out at the Strange Lake Zr – Y – heavy rare earth element deposit in northern Quebec and Labrador, Canada. The heavy mineral (>3.2 specific gravity) and mid-density (3.0–3.2 specific gravity) nonferromagnetic fractions of mineralized bedrock from the deposit and till up to 50 km down ice of the deposit were examined to determine the potential of using rare earth element and high fileld strength element indicator minerals for exploration. The deposit contains oxide, silicate, phosphate, and carbonate indicator minerals, some of which (cerianite, uraninite, fluorapatite, rhabdophane, thorianite, danburite, and aeschynite) have not been reported in previous bedrock studies of Strange Lake. Indicator minerals that could be useful in the exploration for similar deposits include Zr silicates (zircon, secondary gittinsite (CaZrSi2O7), and other hydrated Zr±Y±Ca silicates), pyrochlore ((Na,Ca)2Nb2O6(OH,F)), and thorite (Th(SiO4))/thorianite (ThO2) as well as rare earth element minerals monazite ((La,Ce,Y,Th)PO4), chevkinite ((Ce,La,Ca,Th)4(Fe,Mg)2(Ti,Fe)3Si4O22), parisite (Ca(Ce,La)2(CO3)3F2), bastnaesite (Ce(CO3)F), kainosite (Ca2(Y,Ce)2Si4O12(CO3)·H2O), and allanite ((Ce,Ca,Y)2(Al,Fe)3(SiO4)3(OH)). Rare metal indicator minerals can be added to the expanding list of indicator minerals that can be recovered from surficial sediments and used to explore for a broad range of deposit types and commodities that already include diamonds and precious, base, and strategic metals.

Lanthanides as impurities in the Bayer production cycle of the aluminum hydroxide from Sierra Leone bauxite

“…In these resources, the lanthanides are most often in the form of the following natural mineral phases [3]: a) Carbonate minerals: Bastnaesite (Ce,La)(CO3)F; Parisite Ca(Ce,La)2(CO3)3F2; Synchysite Ca(Ce,La)(CO 3 ) 2 F and Cebaite Ba 3 Ce 2 (CO 3 ) 5 F 2 containing lanthanides [6][7][8]; and Breunerite (Mg,Fe,Sc)CO3 or Dolomite (Ca,Mg,Sc)CO3 (accompanying the silicate albite mineral phase) containing scandium [9]; Yttrium bonded to 25 carbonates compounds. b) Phosphate minerals: Lanthanides in calcium substituted in phosphates as fluoride, chloride or hydroxide) Ca5(PO4)3(F,Cl,OH): Polymetalic monazite; (Ce,La,Nd,Th)PO4: Aluminum phosphates florencite CeAl3(PO4)2(OH)6 containing lanthanides [10][11][12] and Scandium phosphate anhydrous and hydrous species, such as Pretulite (ScPO4) and Kolbeckite (ScPO4 2H2O) [13]; Yttrium phosphate minerals -Xenotime (YPO4) and also, other 9 phosphates, vanadates and arsenates [14]; c) Silicate minerals: Kainosite Ca2(Y,Ce)2Si4O12CO3H2O; Ritholite (Ce,Ca)5(SiO4,PO4)3(OH,F); Gadolinite (Ce,La,Nd,Y)2Fe 2+ Be2Si2O10; Allanite (Ce,Ca,Y)2(Al,Fe 3+ )3(SiO4)3OH, containing lanthanides and yttrium [15][16][17][18]; Scandium as an essential element in the following silicate minerals mono silicate Cascandite Ca(Sc,Fe 2+ )Si3O8(OH)), Cyclosilicate bazzite Be3(Sc,Al)2Si6O18, Disilicate thortveitite (Sc,Y)2Si2 O7), and Orthosilicate eringaite Ca3Sc2 (SiO4)3 [19]. d) Oxide minerals: Fergusonite (Ce,La,Nd)NbO 4 , Loparite (Ce,La,Na,Ca,Sr)(Ti,Nb)O 3 ; Euxenite (Y,Ca,Ce,U,Th)(Nb,Ta,Ti)2O6; Brannerite (U,Ca,Y,Ce)(Ti,Fe)2O6 containing lanthanide and yttrium.…”