Ultrahigh-Temperature Sphalerite from Zn-Cd-Se-Rich Combustion Metamorphic Marbles, Daba Complex, Central Jordan: Paragenesis, Chemistry, and Structure

Abstract

Minerals of the Zn-Cd-S-Se system that formed by moderately reduced ~800–850 °C combustion metamorphic (CM) alteration of marly sediments were found in marbles from central Jordan. Their precursor sediments contain Se- and Ni-enriched authigenic pyrite and ZnS modifications with high Cd enrichment (up to ~10 wt%) and elevated concentrations of Cu, Sb, Ag, Mo, and Pb. The marbles are composed of calcite, carbonate-fluorapatite, spurrite, and brownmillerite and characterized by high P, Zn, Cd, U, and elevated Se, Ni, V, and Mo contents. Main accessories are either Zn-bearing oxides or sphalerite, greenockite, and Ca-Fe-Ni-Cu-O-S-Se oxychalcogenides. CM alteration lead to compositional homogenization of metamorphic sphalerite, for which trace-element suites become less diverse than in the authigenic ZnS. The CM sphalerites contain up to ~14 wt% Cd and ~6.7 wt% Se but are poor in Fe (means 1.4–2.2 wt%), and bear 100–250 ppm Co, Ni, and Hg. Sphalerite (Zn,Cd,Fe)(S,O,Se)cub is a homogeneous solid solution with a unit cell smaller than in ZnScub as a result of S2− → O2− substitution (a = 5.40852(12) Å, V = 158.211(6) Å3). The amount of lattice-bound oxygen in the CM sphalerite is within the range for synthetic ZnS1−xOx crystals (0 < x ≤ 0.05) growing at 900 °C.

Sulfide Minerals as Potential Tracers of Isochemical Processes in Contact Metamorphism: Case Study of the Kochumdek Aureole, East Siberia

“…The obtained results show the compositional features of ultrahigh-temperature sulfides occurring under spurrite-merwinite facies conditions during thermal alteration of marly limestone, which so far has only been achieved for sphalerite from combustion metamorphic rocks [53]. Iron is the principal mineral-forming cation in the Kochumdek marble and, together with Mn, is among main components in the (Zn,Fe,Mn)S cub , (Zn,Mn,Fe)S hex , and (Mn,Fe)S cub solid-solution series, which coexists with the predominant pyrrhotite.…”

“…Trace elements in bulk samples of gabbro, marble, and limestone were determined by mass spectrometry with inductively coupled plasma (ICP-MS) on an Agilent 7700x spectrometer (Agilent Technologies, Inc., Santa Clara, CA, USA) at the SU FRC MG (Miass, Russia). The method was slightly modified from those reported in [51,52] and is described in detail by Sokol et al (2020) [53].…”

Nickolayite, FeMoP, a new natural molybdenum phosphide

“…Since the 1960s it has been documented that the sedimentary strata – the protoliths of pyrometamorphic rocks – are enriched in Ni and Mo (Issar et al , 1969; Ilani et al , 1985; Gilat, 1994; Bogoch et al , 1999; Ryb et al , 2009; Fleurance et al , 2013), and these elevated concentrations are retained in the marbles and paralavas of the Hatrurim Formation. Powellite, CaMoO 4 , an accessory mineral in the rocks of the Mottled Zone, was found both in Israel and Jordan (Khoury, 2020; Sokol et al , 2020). Phosphides of the barringerite–transjordanite series, Fe 2 P–Ni 2 P, occurring on both sides of the Dead Sea, may contain up to 3 wt.% Mo (Britvin et al , 2020a).…”

Ge-Hg-Rich Sphalerite and Pb, Sb, As, Hg, and Ag Sulfide Assemblages in Mud Volcanoes of Sakhalin Island, Russia: An Insight into Possible Origin

“…Trace elements in bulk samples of mud masses and their heavy fractions were determined by mass spectrometry with inductively coupled plasma (ICP-MS) on an Agilent 7700x spectrometer (Agilent Technologies, Inc., Santa Clara, CA, USA) at the SU FRC MG (Miass, Russia). The method was described in detail by [48].…”