Incorporation mechanism of tungsten in W-Fe-Cr-V-bearing rutile

Abstract

Rutile is a common mineral in many types of ore deposits and can carry chemical or isotopic information about the ore formation. For closer understanding of this information, the mechanisms of incorporation of minor elements should be known. In this work, we have investigated natural rutile crystals with elevated concentration of WO 3 (up to 17.7 wt.%), Cr 2 O 3,tot (7.5), V 2 O 3,tot (4.1), FeO tot (7.3), and other metals. X-ray absorption spectroscopy (XAS) on rutile on the Fe K, Cr K, V K, and W L 1 and L 3 edges shows that all cations are coordinated octahedrally. The average oxidation state of V is +3.8, that of Cr near +4. Shell-by-shell fitting of the W L 3 EXAFS data show that W resides in the rutile structure. Raman spectroscopy excluded the possibility of hydrogen as a chargecompensating species. High-resolution TEM and electron diffraction confirm this conclusion as the entire inspected area consists of rutile single crystal with variable amount of metals other than Ti. Our results show that rutile or its precursors can be efficient vehicles for tungsten in sedimentary rocks, leading to their enrichment in W and possibly later fertility This is the peer-reviewed, final accepted version for American Mineralogist, published by the Mineralogical Society of America. The published version is subject to change. Cite as Authors (Year) Title. American Mineralogist, in press.

Hydrothermal fluid signatures of the Yulong porphyry Cu-Mo deposit: Clues from the composition and U-Pb dating of W-bearing rutile

“…Alternatively, the possibility of vacancy-bearing substitutions has been proposed, with hydrogen atoms or OH groups being involved in local charge compensation at the oxygen position in rutile and cassiterite samples (Maldener et al, 2001;Losos and Beran, 2004;Borges et al, 2015). However, recent Raman and X-ray absorption spectroscopy studies of W-rich rutile exclude the possibility of hydrogen acting as a charge balancing species or oxygen vacancies (Majzlan et al, 2021). These suppositions are also not supported by analyses completed in this study.…”

“…We therefore interpret the chemical composition of rutile formed in a hydrothermal ore system to reflect the composition of ore-forming fluids associated with porphyry Cu-Mo mineralization. The crystallographic control of impurities into the rutile lattice during crystal growth can cause compositional variations such as sector zoning (Plavsa et al, 2018;Agangi et al, 2020;Moore et al, 2020;Majzlan et al, 2021). The intensity of backscattered luminescence is related to the relative atomic mass of elements.…”

“…Previous studies have confirmed that rutile can form as a replacement product of Ti-bearing oxides and silicates (such as ilmenite, titanite or biotite), and contains variable concentrations of Fe, V, high field strength elements (HFSE), transition, and base metallic elements (Luvizotto and Zack, 2009;Meinhold, 2010;Plavsa et al, 2018;Agangi et al, 2019). The variable concentrations of trace elements are closely connected to the composition of the primary minerals, type and composition of magmatic and metamorphic fluids (Cl-or F-rich), pressure and temperature conditions, and oxygen fugacity (fO 2 ) (Zack et al, 2002(Zack et al, , 2004Plavsa et al, 2018;Majzlan et al, 2021). Therefore, rutile enriched in V, W, Mo, Sn and Sb can be used as a geochemical fingerprint of a hydrothermal fluid associated with mineralization (c.f.…”

Trace Element Geochemistry in the Earliest Terrestrial Ecosystem, the Rhynie Chert

“…Tungsten, niobium, scandium and antimony can all be enriched within rutile (Černý & Chapman, 2001). Titanium oxides are a primary scavenger and carrier of tungsten in low‐temperature sedimentary rocks (Majzlan et al., 2021), and iron oxides are well known to adsorb antimony in soils (Shangguan et al., 2016). The mineral residence of tungsten and antimony at Rhynie therefore follows their expected distribution.…”

Rutile Mineral Chemistry and Zr-in-Rutile Thermometry in Provenance Study of Albian (Uppermost Lower Cretaceous) Terrigenous Quartz Sands and Sandstones in Southern Extra-Carpathian Poland

“…Zr concentrations in rutile from metamorphic rocks vary in the wide range from several ppm up to 11,000 ppm [29,34,65]. Anomalously high concentrations of transition metals are described only from rutile occurring in some ore deposits, e.g., [66], in which the contents of V 2 O 3 , Cr 2 O 3 , FeO, Nb 2 O 5 , and WO 3 can reach 3.95 wt.%, 3.28 wt.%, 3.27 wt.%, 0.23 wt.%, and 17.73 wt.%, respectively. The common high concentrations of HFSE and other transitional elements (particularly V and Cr) in rutile allow us to estimate rutile crystallization temperatures and discriminate between different source lithologies within source areas (for review, see [54]); both of these methods are commonly used in sediment provenance studies.…”