Major and trace element geochemistry of emerald from several deposits: Implications for genetic models and classification schemes

Aurisicchio, Carlo; Conte, Aida Maria; Medeghini, Laura; Ottolini, Luisa; Vito, Caterina De

doi:10.1016/j.oregeorev.2018.02.001

Cited by 37 publications

(43 citation statements)

References 34 publications

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“…Trace elements of Dayakou samples in the diagram include light elements (LE: Li, B), incompatible elements (IE: Cs−Ti), and transition metal chromophoric elements (CTE: Cr and V). Other trace elements results from worldwide V-dominant emeralds are summarized from the previous work reported by [16,20,21,42].…”

Section: Trace Elements From La-icp-ms Analysismentioning

confidence: 99%

“…The Dayakou deposit was classified as tectonic magmatic-related emerald deposit hosted in meta-sedimentary rocks (Type IB) [10]. Considering the presence of syntectonic intrusions of emerald-bearing pegmatites and quartz veins and the highest concentration of Cs ever reported for emeralds, with average content of 1754 ppm, and with average Li content of 353 ppm, a magmatic origin is preferred for the parental fluids of Dayakou emeralds [1,4,10,14,16,22,51]. In addition, the enrichment of Cs, W, Sn, and As in emeralds and the presence of scheelite, tourmaline in pegmatite veins indicate a supply of alkali and incompatible elements such as Be, Rb, Cs, W, Sn, As, F, and B from the parental fluids.…”

Section: The Origin Of Dayakou Emerald Parental Fluidmentioning

confidence: 99%

“…Various binary diagrams generated from the trace element data highlight peculiar differences inside these V-dominant emerald deposits and show great potential in differentiating the provenance. [46] (average of five analyses), [16,42] (average of three analyses).…”

Section: Geographic Origin Determinationmentioning

confidence: 99%

“…Gray triangular area indicates the V-dominance. Sources of data: [46] (average of five analyses), [16,42] (average of three analyses).…”

Section: Geographic Origin Determinationmentioning

confidence: 99%

“…Most previous works have discussed the element concentration differences among the emerald deposits worldwide. Those studies emphasized the channel cations (Na, K) and isomorphic substituents (Fe, Mg, and chromophoric Cr and V) at the Y, T1, and T2 sites [5,[13][14][15][16][17][18][19]. References [2] and [10] Figure 1.…”

Section: Introductionmentioning

confidence: 99%

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Major and Trace Element Geochemistry of Dayakou Vanadium-Dominant Emerald from Malipo (Yunnan, China): Genetic Model and Geographic Origin Determination

Zheng

Guo

2019

Minerals

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Emerald from the deposit at Dayakou is classified as a vanadium-dominant emerald together with Lened, Muzo, Mohmand, and Eidsvoll emeralds. Although previous studies defined these V-dominant emeralds and traced the genesis of the Dayakou deposit, there has not been any systematic comparison or discrimination on V-dominant emeralds from these deposits. The origin of the parental fluid and the crystallization process of the Dayakou emerald remain controversial. In this study, both major and trace element signatures of 34 V-dominant samples from Dayakou are analyzed through electron microprobe analysis (EMPA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Dayakou emeralds are characterized by high ratios of V/Cr and the enrichment of Li, Cs, W, Sn, and As. These geochemical fingerprints indicate a parental fluid of an Early Cretaceous early-stage granitic fluid associated with Laojunshan granite. The considerable concentration variation of Rb, Cs, Ga and the presence of V-rich oxy-schorl-dravite inclusions in a color zoned sample suggest two generations of emerald precipitation. Thus, a more detailed idealized mineralization model for the Dayakou deposit is proposed. A series of plots, such as Rb vs. Cs, V vs. V/Cr, LILE vs. CTE, and Li vs. Sc, are constructed to discriminate the provenance of V-dominant emeralds. Minerals 2019, 9, 777 2 of 29 summarized emerald deposits worldwide and collected their chemical compositions. They defined Dayakou (China), Lened (Canada), Muzo (Colombia), Mohmand (Pakistan), and Eidsvoll (Norway) emeralds as typical V-dominant emeralds based on the greater content of V 2 O 3 than Cr 2 O 3 . Those V-dominant emeralds can be easily distinguished from Cr-dominant emeralds. However, there has not been a systematic comparison or discrimination of those V-dominant emeralds from various deposits. With regards to Dayakou emeralds, their chemical compositions have been recently reported [20], but not analyzed in detail. Trace elements of emerald are powerful indicators for determining the geographic provenance but the number of related studies is limited. For the first time, using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) and Secondary Ion Mass Spectrometry (SIMS) techniques, [21] and [16] determined the origin of emeralds from several deposits by trace elements data, such as Li, B, Rb, Cs, V, Cr, Sc, Ga, etc. So far, only [20] has reported trace elements of Dayakou emerald, but their work focused on the Al 3+ replacement degree and Cr/V ratio. The geochemical fingerprints of the Dayakou emerald are not yet determined.Besides, the trace element geochemistry of emeralds was used for building the genetic model. B, Ga, Ba, Sr, and alkali elements Li, Cs, and Rb are regarded as indicators of parental fluid and the fractionation and evolution for pegmatite [3,4,22,23]. Reference [24] reported the formation conditions of Dayakou emerald, but the crystallization process and the sources of emerald-forming fluids have yet to be determined.In thi...

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Section: Trace Elements From La-icp-ms Analysismentioning

confidence: 99%