The data obtained from field and geothermometric studies and also the REE composition of fluorites associated with lead mineralization at the Kamar-Mehdi mine are compatible with a structurally controlled, fissure filling, epigenetic, hydrothermal origin. Homogenization and last ice melting temperatures for primary fluid inclusions trapped in fluorite crystals indicate that the mineralizati...

Metals are largely derived from the mantle or crust by partial melting and fluid-related leaching. Ligands can be provided from the same sources, or from the atmosphere, hydrosphere and biosphere. Transport is mainly by mechanical or mass transfer mechanisms and by fluids. On and near the surface, biological processes can also concentrate and transport ore components or remove non-ore component...

Microbial productivity at hydrothermal vents is among the highest found anywhere in the deep ocean, but constraints on microbial growth and metabolism at vents are lacking. We used a combination of cultivation, molecular, and geochemical tools to verify pure culture H(2) threshold measurements for hyperthermophilic methanogenesis in low-temperature hydrothermal fluids from Axial Volcano and End...

Aqueous fluids play a significant role in the transport of heat and matter in the Earth’s crust and the upper mantle, and high-field-strength elements such as Zr are important geochemical tracers for these processes. However, the dissolution mechanism and complexation of Zr in the fluids at high pressure and temperature are unknown, in part because very low concentrations present severe experim...

The 3.43 billion-year-old Strelley Pool Chert, Pilbara Craton, Western Australia, contains compelling evidence of Early Archaean life in the form of kilometre-sized remnants of an ancient stromatolitic carbonate platform. Reviewing and building on earlier studies, we examine the fossilized remains of the platform to seek ecosystem-scale insights to Earth’s early biosphere, examining the evidenc...

Hydrothermal environments are characterised by high metal concentrations related to interactions of the convective seawater circulation with basaltic rocks inside the ocean crust. Thus, hydrothermal fluids are enriched with, among other toxic metals, mercury (Hg) that becomes bioavailable to vent macro invertebrates and that may determine development of specialised defence mechanisms. Unusually...

the nasirabad manganese deposit is located 5 km south of nasirabad, 8 km sw of neyriz in the fars province. structurally, the area is placed in the southeastern part of zagros thrust belt. in this area, the manganese mineralization occurred as ore layers and nodules, interlayered with pichakun radiolarite chert deposits. in this study, mineralogy and geochemistry of uranium, thorium and lead is...