The enrichment characteristics of germanium and it's geological significance in the Banbianjie Ge-Zn deposit,Guizhou

Germanium (Ge)is a strategic and critical mineral resource,and an important raw material for many high.tech fields. Germanium is mainly produced as a by.product of hydrothermal base metal deposits such as Zn,Pb and Cu,as well as coal deposits. The Banbianjie Zn deposit (7. 70Mt ores,with an average Zn grade of 5. 1%),which has recently made significant breakthroughs in mineral exploration,is accompanied by ultra large.scale metal Ge (> 900t @ 110 x 10(-6)). However,the mechanism of Ge super. enrichment is unclear. In this study,we used LA.ICPMS to conduct sphalerite in.situ trace elements and mapping analyses,aiming to elucidate the occurrence and substitution of Ge and other dispersed elements. The results reveal that high concentrations (average > 100 x 10(-6))trace elements in sphalerite from the Banbianjie deposit is characterized by Fe,Pb,Ge and Cd,relatively high concentrations (average 100 x10(-6) - 10 x10(-) (6))trace elements are Mn,Ga,Sn and Tl,and the low concentrations (average value < 10 x10(-6))trace elements are Ag,Cu,In and Sb. Compared with other types of Pb.Zn deposits,The sphalerite from Banbianjie shows exceptional Ge enrichment (274 x10 - 6 similar to 1938 x10(-6),average 1055 x10(-6)). LA-ICPMS time.resolved depth profile and micro.area mapping analysis demonstrate that Ge occurs in sphalerite in an isomorphic or nanoparticle manner. Trace element molar correlation diagrams suggest that Ge substitutes Zn predominantly by Ge4+ + Pb2+ <-> 3Zn(2+),followed by nGe(4+) + Mn2+ <-> (2n + 1)Zn2+ and nGe(4+) + 2Tl(3+)<-> (2n + 3)Zn2+. Based on comprehensive analysis,it is believed that the Ge in the Banbianjie deposit may have originated from a relatively Ge rich Precambrian basements;Organic basin fluids play an important role in the transport of Ge;The symbiotic differentiation of rare and dispersed elements such as Ge and Cd restricts the ultimate supernormal enrichment of Ge. Therefore,the supernormal enrichment of Ge in the Banbianjie deposit is the result of the complex process of "source,transport,and accumulation"and the coupling of multiple factors