Co-variability of S6+, S4+, and S2−in apatite as a function of oxidation state: Implications for a new oxybarometer

Konecke, Brian A.; Fiege, Adrian; Simon, Adam C.; Parat, Fleurice; Stechern, André

doi:10.2138/am-2017-5907

Cited by 118 publications

(45 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…; Konecke et al. ). In terrestrial samples, apatite is considered a versatile mineral to provide insights into various geological characteristics and processes, ranging from magmatic (Webster and Piccoli ) to metasomatic processes (Harlov ), to geochronology (Chew and Spikings ) to understanding the magma source regions based on apatite trace element compositions (Mao et al.…”

Section: Introductionmentioning

confidence: 97%

“…Likewise, apatite and merrillite became a common target for studying volatiles in the meteoritic record, including Martian meteorites Bellucci et al 2017) and meteorites thought to have originated from Vesta (Sarafian et al 2013;Barrett et al 2016). Recently, apatite has also been recognized as a potential oxybarometer (Economos et al 2017;Konecke et al 2017). In terrestrial samples, apatite is considered a versatile mineral to provide insights into various geological characteristics and processes, ranging from magmatic (Webster and Piccoli 2015) to metasomatic processes (Harlov 2015), to geochronology (Chew and Spikings 2015) to understanding the magma source regions based on apatite trace element compositions (Mao et al 2016;Bruand et al 2017).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Shock‐induced microtextures in lunar apatite and merrillite

Černok

White

Darling

et al. 2019

Meteorit & Planetary Scien

View full text Add to dashboard Cite

Apatite and merrillite are the most common phosphate minerals in a wide range of planetary materials and are key accessory phases for in situ age dating, as well as for determination of the volatile abundances and their isotopic composition. Although most lunar and meteoritic samples show at least some evidence of impact metamorphism, relatively little is known about how these two phosphates respond to shock‐loading. In this work, we analyzed a set of well‐studied lunar highlands samples (Apollo 17 Mg‐suite rocks 76535, 76335, 72255, 78235, and 78236), in order of displaying increasing shock deformation stages from S1 to S6. We determined the stage of shock deformation of the rock based on existing plagioclase shock‐pressure barometry using optical microscopy, Raman spectroscopy, and SEM‐based panchromatic cathodoluminescence (CL) imaging of plagioclase. We then inspected the microtexture of apatite and merrillite through an integrated study of Raman spectroscopy, SEM‐CL imaging, and electron backscatter diffraction (EBSD). EBSD analyses revealed that microtextures in apatite and merrillite become progressively more complex and deformed with increasing levels of shock‐loading. An early shock‐stage fragmentation at S1 and S2 is followed by subgrain formation from S2 onward, showing consistent decrease in subgrain size with increasing level of deformation (up to S5) and finally granularization of grains caused by recrystallization (S6). Starting with 2°–3° of intragrain crystal‐plastic deformation in both phosphates at the lowest shock stage, apatite undergoes up to 25° and merrillite up to 30° of crystal‐plastic deformation at the highest stage of shock deformation (S5). Merrillite displays lower shock impedance than apatite; hence, it is more deformed at the same level of shock‐loading. We suggest that the microtexture of apatite and merrillite visualized by EBSD can be used to evaluate stages of shock deformation and should be taken into account when interpreting in situ geochemically relevant analyses of the phosphates, e.g., age or volatile content, as it has been shown in other accessory minerals that differently shocked domains can yield significantly different ages.

show abstract

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Shock‐induced microtextures in lunar apatite and merrillite

Černok

White

Darling

et al. 2019

Meteorit & Planetary Scien

View full text Add to dashboard Cite

show abstract

“…Sulfur has been proposed to enter the apatite crystal structure mainly in the oxidized form S 6+ by replacing P 5+ through a charge-balanced coupled substitution possibly involving Na + , Si 4+ , REE 3+ and Y 3+ cations (Rouse and Dunn 1982;Liu and Comodi 1993;Tepper and Kuehner 1999;Parat et al 2002). A recent S XANES study has shown that minor amounts of S 4+ and S 2− can also enter the structure of apatite as a function of oxygen fugacity (Konecke et al 2017). However, due to the expected low abundance of S 4+ and S 2− in magmatic apatite (likely << 300 ppm), we will assume that all S we analyzed is in the form of S 6+ ions.…”

Section: Apatitementioning

confidence: 99%

“…Apatite from the gabbrodiorite complex systematically returns very low sulfur concentrations (< 0.1 wt% SO 3 ). These low values may either (1) reflect low magmatic sulfur content of the basaltic magma or (2) ƒO 2 conditions at which the dominant sulfur specie is S 2− (Jugo et al 2010;Baker and Moretti 2011) and thus cannot enter the apatite structure in high amounts (Parat et al 2011b;Konecke et al 2017). At the time of apatite saturation (> 850 °C), the interstitial melt likely was fluid saturated and a fraction of the sulfur would have partitioned into the degassing magmatic fluid.…”

Section: Sulfur Concentration Of the Meltmentioning

confidence: 99%

Amphibole and apatite insights into the evolution and mass balance of Cl and S in magmas associated with porphyry copper deposits

Chelle-Michou

Chiaradia

2017

Contrib Mineral Petrol

View full text Add to dashboard Cite

Chlorine and sulfur are of paramount importance for supporting the transport and deposition of ore metals at magmatichydrothermal systems such as the Coroccohuayco Fe-Cu-Au porphyry-skarn deposit, Peru. Here, we used recent partitioning models to determine the Cl and S concentration of the melts from the Coroccohuayco magmatic suite using apatite and amphibole chemical analyses. The pre-mineralization gabbrodiorite complex hosts S-poor apatite, while the syn-and post-ore dacitic porphyries host S-rich apatite. Our apatite data on the Coroccohuayco magmatic suite are consistent with an increasing oxygen fugacity (from the gabbrodiorite complex to the porphyries) causing the dominant sulfur species to shift from S 2− to S 6+ at upper crustal pressure where the magmas were emplaced. We suggest that this change in sulfur speciation could have favored S degassing, rather than its sequestration in magmatic sulfides. Using available partitioning models for apatite from the porphyries, pre-degassing S melt concentration was 20-200 ppm. Estimates of absolute magmatic Cl concentrations using amphibole and apatite gave highly contrasting results. Cl melt concentrations obtained from apatite (0.60 wt% for the gabbrodiorite complex; 0.2-0.3 wt% for the porphyries) seems much more reasonable than those obtained from amphibole which are very low (0.37 wt% for the gabbrodiorite complex; 0.10 wt% for the porphyries). In turn, relative variations of the Cl melt concentrations obtained from amphibole during magma cooling are compatible with previous petrological constraints on the Coroccohuayco magmatic suite. This confirms that the gabbrodioritic magma was initially fluid undersaturated upon emplacement, and that magmatic fluid exsolution of the gabbrodiorite and the pluton rooting the porphyry stocks and dikes were emplaced and degassed at 100-200 MPa. Finally, mass balance constraints on S, Cu and Cl were used to estimate the minimum volume of magma required to form the Coroccohuayco deposit. These three estimates are remarkably consistent among each other (ca. 100 km 3 ) and suggest that the Cl melt concentration is at least as critical as that of Cu and S to form an economic mineralization.

show abstract

“…However, experimental and ab initio studies have shown that apatite, which has been assumed typically to accommodate sulfur as S 6+ only (e.g. Pan and Fleet, 2002), is also capable of accommodating more reduced varieties of S such as S 4+ and S 2- (Konecke et al, 2017a;Kim et al, 2017). There has been no direct investigation into the redox state of S in monazite-(Ce) to investigate its capability to accommodate S in different oxidation states.…”

Section: Introductionmentioning

confidence: 99%

Sulfur-bearing monazite-(Ce) from the Eureka carbonatite, Namibia: oxidation state, substitution mechanism, and formation conditions

Broom-Fendley

Smith

Andrade

et al. 2019

MinMag

View full text Add to dashboard Cite

Sulfur-bearing monazite-(Ce) occurs in silicified carbonatite at Eureka, Namibia, forming rims up to ~0.5 mm thick on earlier-formed monazite-(Ce) megacrysts. We present X-ray photoelectron spectroscopy data demonstrating that sulfur is accommodated predominantly in monazite-(Ce) as sulfate, via a clino-anhydrite-type coupled substitution mechanism. Minor sulfide and sulfite peaks in the X-ray photoelectron spectra, however, also indicate that more complex substitution mechanisms incorporating S2– and S4+ are possible. Incorporation of S6+ through clino-anhydrite-type substitution results in an excess of M2+ cations, which previous workers have suggested is accommodated by auxiliary substitution of OH– for O2–. However, Raman data show no indication of OH–, and instead we suggest charge imbalance is accommodated through F– substituting for O2–. The accommodation of S in the monazite-(Ce) results in considerable structural distortion that may account for relatively high contents of ions with radii beyond those normally found in monazite-(Ce), such as the heavy rare earth elements, Mo, Zr and V. In contrast to S-bearing monazite-(Ce) in other carbonatites, S-bearing monazite-(Ce) at Eureka formed via a dissolution–precipitation mechanism during prolonged weathering, with S derived from an aeolian source. While large S-bearing monazite-(Ce) grains are likely to be rare in the geological record, formation of secondary S-bearing monazite-(Ce) in these conditions may be a feasible mineral for dating palaeo-weathering horizons.

show abstract

Co-variability of S⁶⁺, S⁴⁺, and S²⁻in apatite as a function of oxidation state: Implications for a new oxybarometer

Cited by 118 publications

References 52 publications

Shock‐induced microtextures in lunar apatite and merrillite

Shock‐induced microtextures in lunar apatite and merrillite

Amphibole and apatite insights into the evolution and mass balance of Cl and S in magmas associated with porphyry copper deposits

Sulfur-bearing monazite-(Ce) from the Eureka carbonatite, Namibia: oxidation state, substitution mechanism, and formation conditions

Contact Info

Product

Resources

About