Studies of secondary mineral formation in the PbO-H<sub>2</sub>O-HC1 system

Edwards, R. W.

doi:10.1180/minmag.1992.056.382.07

Cited by 55 publications

(72 citation statements)

References 19 publications

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“…The first step in the recipe is to form laurionite by stirring PbO (litharge) with NaCl (salt): PbO + NaCl + H 2 O → Pb(OH)Cl + NaOH. When carbon dioxide is added in the solution, the chemistry of lead oxychloride is altered and phosgenite forms 34 : 2Pb(OH)Cl (s) + CO 2(g) → Pb 2 Cl 2 CO 3(s) + H 2 O. The CO 2(g) provides the radioactive isotope 14 C used for dating the cosmetics.…”

Section: Discussionmentioning

confidence: 99%

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Absolute dating of lead carbonates in ancient cosmetics by radiocarbon

et al. 2018

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Lead carbonate is one of the major compounds of art and archeology used as an ingredient in paint and cosmetics since Antiquity. Accelerator mass spectrometry radiocarbon dating is usually applied to organic remains. Here we extend radiocarbon dating to lead carbonate, an inorganic material. We demonstrate that lead carbonates can be dated. We also show that natural and manufactured make-up powders can be discriminated by radiocarbon. We find that cerussite used for cosmetics was a natural mineral during the Egyptian Kingdom and then a synthesized compound manufactured by the ancient Greeks. Furthermore, we confirm that phosgenite was artificially produced by the Egyptians about 3500 years ago. Our results confirm the expertize of ancient Egyptians and Greeks in the chemical synthesis of cosmetics. The detection of radiocarbon in lead carbonate holds great promise for art history and provides a new tool for the authentication of paintings by dating the lead white pigment.

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Section: Discussionmentioning

confidence: 99%

“…The term of natron is vague and can refer to many phases of sodium carbonates (Na 2 CO 3 and its hydrated forms or NaHCO 3 (bicarbonate)) 35 . Natural sodium carbonates from the Wadi El Natrum depression were known by the ancient Egyptians 34 . They are formed during the drying up of salt lakes in summer.…”

Section: Discussionmentioning

confidence: 99%

Absolute dating of lead carbonates in ancient cosmetics by radiocarbon

et al. 2018

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“…Several assemblages characteristic of the latestage fissures in the Långban mineralization can be connected with distinct types of occurrences, and thus, distinct processes of formation worldwide. Indeed, the Pb oxychloride minerals comprise a group of chemically and genetically related minerals, which chiefly occur as rare late-stage, low-pressure and low-temperature phases in both marine altered slags and artifacts (e.g., Edwards et al 1992), zones of supergene alteration in base-metal ore deposits (Scott 1994), as well as late-stage fissure or Schlieren assemblages in complex FeMn-oxide ore deposits, such as the Kombat mine, Namibia (Dunn 1991). It unfortunately is rare to find well-defined constraints on mineral stability useful to evaluate fissure formation at Långban and related deposits, but the presence of domeykite ("␣-domeykite" of the older literature) associated with calcite and pyroaurite (± arsenosilicate minerals) in partly open fissures suggests a temperature of formation below 90°C (Burke 1986, Skinner & Luce 1971.…”

Section: Discussionmentioning

confidence: 99%

FLUID INCLUSIONS IN LATE-STAGE Pb Mn As Sb MINERAL ASSEMBLAGES IN THE LANGBAN DEPOSIT, BERGSLAGEN, SWEDEN

Broman

2002

The Canadian Mineralogist

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The Långban deposit in the Paleoproterozoic Bergslagen ore province in southwestern central Sweden is well known for its complex and unique mineralogy. The largest number of exotic species occur in late-stage Pb-Mn-As-Sb-bearing fissures of disputed origin. Fluid inclusions in fissure-hosted allactite, barite, blixite, calcite, sarkinite, tilasite and finnemanite suggest a low-temperature near-surface formation at, or close to, atmospheric pressure, from aqueous NaCl-CaCl 2 -MgCl 2 solutions of initially moderate salinity. Mineral formation started at temperatures of ca. 180°C, with the fluid evolving through reactions with Mn-oxide-bearing dolomites and a sequence of boiling events, initiated by repeated fracturing, at temperatures fluctuating between ca. 80 and 130°C. This main stage is characterized by precipitation of alternating species (e.g., barite, calcite, allactite, native lead, pyrochroite), with solutions evolving further to heterogeneous high-salinity compositions at temperatures less than ca. 70°C. Late low-salinity inclusions formed through partial condensation of the expelled vapor phase. Continued formation of minerals (e.g., arsenites, H 2 O-rich arsenates) after the major boiling events is characterized by temperatures decreasing well below 70°C. The solutions responsible for the specific fissure-mineralization at Långban were introduced in a very shallow postSvecokarelian brittle tectonic environment, in conjunction with a ca. 1 Ga tectonothermal episode, or possibly coupled to post-1.8-Ga granitic magmatism. The absence of similar mineralized systems of brittle fissures on a regional scale suggests that the metals in the Långban fissures were derived very locally from the pre-existing volcanic-exhalative mineralization and not introduced from an external source.Keywords: Långban, ore deposit, fluid inclusions, allactite, barite, blixite, calcite, finnemanite, sarkinite, tilasite, Bergslagen, Sweden. SOMMAIRELe gisement de Långban, dans la province métallogénique paléoprotérozoïque de Bergslagen, dans le secteur sud-ouest central de la Suède, est reconnu pour ses assemblages complexes et uniques de minéraux. La majorité des espèces exotiques se trouvent dans les fissures tardives à Pb-Mn-As-Sb, d'origine controversée. Les inclusions fluides des minéraux déposés dans ces fissures, par exemple allactite, barite, blixite, calcite, sarkinite, tilasite et finnemanite, indiquent une faible température et une déposition à pression atmosphérique, ou presque, à partir de solutions contenant NaCl-CaCl 2 -MgCl 2 , de salinité intermédiaire, au moins au début. La formation de ces assemblages à débuté à environ 180°C, et les fluides ont évolué par réaction avec une séquence de dolomies manganifères et une série d'événements d'ébullition initiés par ouverture répétée de fractures à une température fluctuant entre 80 et 130°C. L'étape principale est marquée par la précipitation d'une alternance d'espèces (e.g., barite, calcite, allactite, plomb natif, pyrochroïte), et par l'évolution progressive des...

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“…However, the solubility of laurionite, PbClOH(s) is much lower: log 10 K s0°≈ -13.27 [74DZc], and this phase might affect the speciation of Pb II in heavily polluted saline water systems. A number of other "mixed" solids have been reported in the Pb 2+ + Cl -+ OH -system [92EDW]. However, as they have not been well characterized they are not included in this evaluation.…”

Section: The Pb 2+ + CL -Systemmentioning

confidence: 99%

Chemical speciation of environmentally significant metals with inorganic ligands. Part 3: The Pb2+ + OH–, Cl–, CO32–, SO42–, and PO43– systems (IUPAC Technical Report)

Powell

Brown

Byrne

et al. 2009

Pure and Applied Chemistry

141

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Complex formation between Pb II and the common environmental inorganic ligands, Cl -, OH -, CO 3 2-, SO 4 2-, and PO 4 3-, can be significant in natural waters with low concentrations of organic matter. Numerical modeling of the speciation of Pb II amongst these inorganic ligands requires reliable values for the relevant stability (formation) constants. This paper provides a critical review of such constants and related thermodynamic data. It recommends values of log 10 β p,q,r°v alid at I m = 0 mol kg -1 and 25 °C (298.15 K), along with the equations and empirical coefficients required to calculate log 10 β p,q,r values at higher ionic strengths using the Brønsted-Guggenheim-Scatchard specific ion interaction theory (SIT). Some values for reaction enthalpies, Δ r H, are also reported.In weakly acidic fresh water systems (-log 10 {[H + ]/c°} < 6), the speciation of Pb II is similar to that of Cu II . In the absence of organic ligands, Pb II speciation is dominated by Pb 2+ (aq), with PbSO 4 (aq) as a minor species. In weakly alkaline solutions, 8.0 < -log 10 {[H + ]/c°} < 9.0, the speciation is dominated by the carbonato species PbCO 3 (aq) and Pb(CO 3 ) 2 2-. In weakly acidic saline systems (-log 10 {[H + ]/c°} < 6), the speciation is dominated by PbCl n (2-n)+ complexes, (n = 0-3), with Pb 2+ (aq) as a minor species. In this medium (and in seawater), the speciation contrasts with that of Cu II because of the higher stability of the Pb 2+ -chlorido-complexes. In seawater at -log 10 {[H + ]/c°} = 8.2, the calculated speciation is less well defined, although it is clearly dominated by the uncharged species PbCO 3 (aq) (41 % of [Pb] T ) with a significant contribution (16 %) from Pb(CO 3 )Cl -and minor contributions (5-10 %) from PbCl n (2-n)+ , (n = 0-3) and Pb(CO 3 ) 2 2-. The uncertainty in calculations of Pb II speciation in seawater arises from (a) the large uncertainty in the stability constant for the apparently dominant species PbCO 3 (aq), (b) the reliance on statistical predictions for stability constants of the ternary species Pb(CO 3 )Cl -and Pb(CO 3 )OH -, and (c) the uncertainty in the stability constant for PbCl 4 2-, the available value being considered

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Studies of secondary mineral formation in the PbO-H₂O-HC1 system

Cited by 55 publications

References 19 publications

Absolute dating of lead carbonates in ancient cosmetics by radiocarbon

Absolute dating of lead carbonates in ancient cosmetics by radiocarbon

FLUID INCLUSIONS IN LATE-STAGE Pb Mn As Sb MINERAL ASSEMBLAGES IN THE LANGBAN DEPOSIT, BERGSLAGEN, SWEDEN

Chemical speciation of environmentally significant metals with inorganic ligands. Part 3: The Pb2+ + OH–, Cl–, CO32–, SO42–, and PO43– systems (IUPAC Technical Report)

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Studies of secondary mineral formation in the PbO-H2O-HC1 system

Cited by 55 publications

References 19 publications

Absolute dating of lead carbonates in ancient cosmetics by radiocarbon

Absolute dating of lead carbonates in ancient cosmetics by radiocarbon

FLUID INCLUSIONS IN LATE-STAGE Pb Mn As Sb MINERAL ASSEMBLAGES IN THE LANGBAN DEPOSIT, BERGSLAGEN, SWEDEN

Chemical speciation of environmentally significant metals with inorganic ligands. Part 3: The Pb2+ + OH–, Cl–, CO32–, SO42–, and PO43– systems (IUPAC Technical Report)

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Studies of secondary mineral formation in the PbO-H₂O-HC1 system