Abstract
The colloform pyrite variety incorporates many trace elements that are released in the environment during rapid oxidation. Colloform pyrite from the Chiprovtsi silver–lead deposit in Bulgaria and its oxidation efflorescent products were studied using X-ray diffractometry, scanning electron microscopy, electron microprobe analysis, and laser ablation inductively coupled plasma mass spectrometry. Pyrite is enriched with (in ppm): Co (0.1–964), Ni (1.8–3858), Cu (2.9–3188), Zn (3.1–77), Ag (1.2–1771), As (8179–52,787), Se (2.7–21.7), Sb (48–17792), Hg (4–2854), Tl (1.7–2336), Pb (13–7072), and Au (0.07–2.77). Gypsum, anhydrite, szomolnokite, halotrichite, römerite, copiapite, aluminocopiapite, magnesiocopiapite, coquimbite, aluminocoquimbite, voltaite, and ammoniomagnesiovoltaite were identified in the efflorescent sulfate assemblage. Sulfate minerals contain not only inherited elements from pyrite (Cr, Fe, Co, Ni, Cu, Zn, Ag, In, As, Sb, Hg, Tl, and Pb), but also newly introduced elements (Na, Mg, Al, Si, P, K, Ca, Sc, Ti, V, Mn, Ga, Rb, Sr, Y, Zr, Sn, Cs, Ba, REE, U, and Th). Voltaite group minerals, copiapite, magnesiocopiapite, and römerite incorporate most of the trace elements, especially the most hazardous As, Sb, Hg, and Tl. Colloform pyrite occurrence in the Chiprovtsi deposit is limited. Its association with marbles would further restrict the oxidation and release of hazardous elements into the environment.
Highlights
Pyrite is the most worldwide abundant sulfide mineral, occurring as a major constituent in ore mineralizations of various types and origin
We report data on the trace element composition of colloform pyrite from the
(1) aggregates aggregates containing containing abundant abundant colloform colloform pyrite pyrite from the low-temperature hydrothermal mineralization occurring in the eastern part of Chiprovtsi from the low-temperature hydrothermal mineralization occurring in the easternthepart of the deposit; underground mine workings level 550 at (Velin and section)
Summary
Pyrite is the most worldwide abundant sulfide mineral, occurring as a major constituent in ore mineralizations of various types and origin (from magmatic and hydrothermal to sedimentary geologic environments). Recent studies of its trace element geochemistry show trends of element associations in different deposit types [2,3,4,5,6,7,8]. This feature determined pyrite as a mineral marker for the evolution of a hydrothermal fluid both in time and space. It is considered that As content electrochemically facilitates Au deposition in the cracks [1,19]. It is used as a source for the extraction of gold and other
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