Niobium and tantalum in minerals: Siderophile, chalcophile or lithophile, and polyvalent

Martin, Robert F.; Wülser, Pierre-Alain

doi:10.1016/j.gexplo.2014.05.006

Cited by 17 publications

(9 citation statements)

References 34 publications

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“…It is more likely that they merely reflect the conditions during tin ore smelting because they usually behave lithophile and thus partition to the slag. Depending on the redox conditions during the smelting process and the valance state in minerals (accompanying cassiterite), tungsten and niobium can, however, be transferred to a limited extent to the metallic phase [100]. The same applies to manganese that is normally not reduced during smelting.…”

Section: Resultsmentioning

confidence: 99%

Isotope systematics and chemical composition of tin ingots from Mochlos (Crete) and other Late Bronze Age sites in the eastern Mediterranean Sea: An ultimate key to tin provenance?

et al. 2019

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The origin of the tin used for the production of bronze in the Eurasian Bronze Age is still one of the mysteries in prehistoric archaeology. In the past, numerous studies were carried out on archaeological bronze and tin objects with the aim of determining the sources of tin, but all failed to find suitable fingerprints. In this paper we investigate a set of 27 tin ingots from well-known sites in the eastern Mediterranean Sea (Mochlos, Uluburun, Hishuley Carmel, Kfar Samir south, Haifa) that had been the subject of previous archaeological and archaeometallurgical research. By using a combined approach of tin and lead isotopes together with trace elements it is possible to narrow down the potential sources of tin for the first time. The strongly radiogenic composition of lead in the tin ingots from Israel allows the calculation of a geological model age of the parental tin ores of 291 ± 17 Ma. This theoretical formation age excludes Anatolian, central Asian and Egyptian tin deposits as tin sources since they formed either much earlier or later. On the other hand, European tin deposits of the Variscan orogeny agree well with this time span so that an origin from European deposits is suggested. With the help of the tin isotope composition and the trace elements of the objects it is further possible to exclude many tin resources from the European continent and, considering the current state of knowledge and the available data, to conclude that Cornish tin mines are the most likely suppliers for the 13 th –12 th centuries tin ingots from Israel. Even though a different provenance seems to be suggested for the tin from Mochlos and Uluburun by the actual data, these findings are of great importance for the archaeological interpretation of the trade routes and the circulation of tin during the Late Bronze Age. They demonstrate that the trade networks between the eastern Mediterranean and some place in the east that are assumed for the first half of the 2 nd millennium BCE (as indicated by textual evidence from Kültepe/Kaneš and Mari) did not exist in the same way towards the last quarter of the millennium.

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Section: Resultsmentioning

confidence: 99%

Isotope systematics and chemical composition of tin ingots from Mochlos (Crete) and other Late Bronze Age sites in the eastern Mediterranean Sea: An ultimate key to tin provenance?

et al. 2019

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“…For example, Guerin (2011) described fergusonite (Y,REE)NbO 4 and hochelagaitie [(Ca,Na,Sr)Nb 4 ] 11 ·8H 2 O from intrusive rocks at the Boddington Cu-Au(Mo) deposit. Conversely, the study of Martin and Wülser (2014) on edgarite, FeNb 3 S 6, provided an excellent example of Nb as a chalcophile element and showed that the structure of Fe x Nb y S 2 is composed of molybdenite-like layers accommodating Nb atoms sandwiched by planes of S atoms in a hexagonal array resorption. The whole assemblage is subalkaline and reducing, and thus the metasomatic fluid that mobilized Nb, Fe, Ti, W, V and Mo was acidic and a carrier of H 2 S. Using SEM, no Nb-bearing phases have been recorded in our set of molybdenite samples.…”

Section: Tungsten In Molybdenitementioning

confidence: 99%

Laser ablation ICPMS study of trace element chemistry in molybdenite coupled with scanning electron microscopy (SEM) — An important tool for identification of different types of mineralization

Pašava

Svojtka

Veselovský

et al. 2016

Ore Geology Reviews

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“…This feature is related to an electronic transition from the 1s-orbital to the 4d-orbital manifold and has already been observed in niobium(V) oxide (Nb 2 O 5 ). 39 A systematic study 38 of minerals containing Nb 0 , Nb 2+ , Nb 4+ , and Nb 5+ ions utilizing Nb K-edge XANES has shown that the pre-edge feature is typically only seen for +5 and mixed valent +4/+5 and is absent for other oxidation states irrespective of geometry. Our analysis confirms that this trend also holds for Nb 3+ species.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Molecular Niobium Precursors in Various Oxidation States: An XAS Case Study

et al. 2018

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Although X-ray absorption spectroscopy (XAS) has become an indispensable tool in characterization of solidstate materials, it is less of a staple in molecular chemistry of niobium. Scattering X-ray techniques remain relatively unexplored for the systematic study of molecular niobium compounds. Here, we use XAS to probe the niobium environment in commonly used Nb precursors in +V, +IV, and +III oxidation states. Apart from laying out the guidelines for identification of niobium oxidation states, we correlate our data with density functional theory models to provide further structural insight. Of particular note, we are able to shed light on the nature of the commonly used and catalytically competent NbCl 3 (DME), which had not been previously characterized structurally despite its prevalence in Nb chemistry.

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Niobium and tantalum in minerals: Siderophile, chalcophile or lithophile, and polyvalent

Cited by 17 publications

References 34 publications

Isotope systematics and chemical composition of tin ingots from Mochlos (Crete) and other Late Bronze Age sites in the eastern Mediterranean Sea: An ultimate key to tin provenance?

Isotope systematics and chemical composition of tin ingots from Mochlos (Crete) and other Late Bronze Age sites in the eastern Mediterranean Sea: An ultimate key to tin provenance?

Laser ablation ICPMS study of trace element chemistry in molybdenite coupled with scanning electron microscopy (SEM) — An important tool for identification of different types of mineralization

Molecular Niobium Precursors in Various Oxidation States: An XAS Case Study

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