Intergrowth texture in Au-Ag-Te minerals from Sandaowanzi gold deposit, Heilongjiang Province: Implications for ore-forming environment

Abstract

Sandaowanzi gold deposit, Heilongjiang Province, is the only single telluride type gold deposit so far documented in the world, in which 90% of gold is hosted in gold-silver telluride minerals. Optical microscope observation, scanning electron microscope, electron probe and X-ray diffraction analysis identified abundant intergrowth textures in the Au-Ag-Te minerals, typified by sylvanite-hosting hessite crystals and hessite-hosting petzite crystals. The intergrown minerals and their chemistry are consistent, and the hosted minerals are mostly worm-like or as oriented stripes, evenly distributed in the hosting minerals, with clear and smooth interfaces. These suggest an exsolution origin for the intergrowth texture. With reference to the phase-transformation temperature derived from synthesis experiments of tellurides, the exsolution texture of Au-Ag-Te minerals implies that the veined tellurides formed at 150-220°C. The early stage disseminated tellurides formed at log f(Te 2 ) from 13.6 to 7.8, log f(S 2 ) from 11.7 to 7.6, whereas the late stage veined tellurides formed at log f(Te 2 ) ranging from 11.2 to 9.7 and log f(S 2 ) from 16.8 to 12.2.Sandaowanzi gold deposit, Au-Ag tellurides, intergrowth texture, mineralization environment Citation:

Oxygen isotope evidence for input of magmatic fluids and precipitation of Au-Ag-tellurides in an otherwise ordinary adularia-sericite epithermal system in NE China

“…DOI: https://doi.org/10.2138/am-2021-7825. http://www.minsocam.org/ grade of g/t, and 34 t of Te at an average grade of g/t from gold-bearing quartz veins hosted in Early Cretaceous volcanic rocks (Yu et al 2012;Xu et al 2012;Liu et al 2013;Zhai and Liu 2014;Gao et al 2017). Sandaowanzi is hosted in the Lower Cretaceous Longjiang (121.7 Ma) Formation (Fm.).…”

Generation of AupAgqTer clusters via laser ablation synthesis using Au‐Ag‐Te nano‐composite as precursor: quadrupole ion‐trap time‐of‐flight mass spectrometry

“…Tellurides often show interesting physical properties such as semi‐ and superconductivity, photovoltaic and thermoelectric activity . Gold tellurides include minerals such as calaverite, krennerite (AuTe 2 ) and montebrazite (Au 2 Te 3 ) . They are good metallic conductors and act as superconductors at low temperature.…”