Using whole rock and in situ pyrite chemistry to evaluate authigenic and hydrothermal controls on trace element variability in a Zn mineralized Proterozoic subbasin

The mid-Proterozoic stratigraphy of the McArthur Basin (Australia) contains some most well-preserved sedimentary rocks Precambrian age, which are also host to giant, clastic dominant (CD-type) massive sulfide Zn deposits. recently discovered CD-type deposit (the Teena deposit) is located in subbasin and hosted by 1.64 Ga Barney Creek Formation. subbasin, therefore, provides perfect natural laboratory for evaluating authigenic hydrothermal controls on trace element (TE) variability, both contribute paleoenvironmental reconstructions ore models. As formed beneath paleoseafloor, this opportunity evaluate TE zonation around a fossilized subseafloor replacement system. In situ laser ablation inductively coupled mass spectrometry (LA-ICP-MS) has been used define compositional end members diagenetic pyrite. overgrowth sulfides pyrite associated with anomalism (Tl, Pb, As, Zn) that extends > 100 meters above main high grade mineralization subbasin. vertical TEs consistent infiltration fluids into overlying hangingwall sediments were undergoing diagenesis. Bulk rock lithogeochemical data record covariation between total organic carbon (TOC) suite (Mo, Co, Ni, V). We suggest was caused local hydrographic factors during deposition High TOC/P molar ratios, resulting from regeneration P euxinic water column, an interval maximum flooding surface relationships TOC, resemble redox architecture silled basin rather than open marine margin. Sulfidic conditions developed periods productivity, linked nutrient supply enhanced connectivity surrounding masses. evidence bistability, involving delicate balance ferruginous (anoxic, non-sulfidic) (sulfidic) conditions, recent models other units. Nevertheless, there strong localised (101 km2) control chemistry Formation highlights key challenge when extrapolating collected partially restricted intracontinental settings.