Fluid inclusion studies on the porphyry-type ore deposits at Bingham, Utah, Butte, Montana, and Climax, Colorado

Tourmaline of the Mramorny Tin Cluster, Chukotka Peninsula, Russia

“…NaCl), and gas, and this phase separation was responsible for ore deposition. The initial high temperatures (>420°C), an immiscibility of mineralizing fluids, the presence of chloride brines in inclusions, a wide range of homogenization temperatures and salinity, and a combination of various types of inclusions all show the similarity of the ore-forming process in the Mramorny cluster to PTX conditions at typical porphyry-copper deposits (Roedder 1971, Nash 1976, Eastoe 1978, Ahmad & Rose 1980, Bloom 1981, Ruggieri et al 1997, Harris et al 2005, Frikken et al 2005. As seen from the aforementioned evidence, there are several identical characteristic features at the three locations: (1) relation to hydrothermally altered porphyritic rhyolite or brecciation zones in rhyolite; (2) at Sukhoi and Nadezhda, cassiterite was identified, and the Mount Seraya occurrence is characterized by anomalous concentrations of tin in the alluvium of first-order streams; (3) identical minerals are associated with tourmaline; (4) similar chemical compositions of tourmalines are found in different locations, and (5) the ratio Fe 3+ /Fe tot is relatively high in the tourmalines.…”

Fluids in the Continental Crust

“…Early studies of porphyry copper deposits confirmed the presence of abundant Na and K in the ore-forming fluids, based on optical identification of halite (NaCl) and sylvite (KCl) daughter minerals in the inclusions (Roedder, 1971a). More recently, the introduction of analytical techniques such as laser ablation ICP-MS has confirmed that Na and K are among the most abundant cations in the fluids, but have also shown that Fe is sometimes the second-most abundant cation and that porphyry-forming fluids should more appropriately considered to be (Na,K,Fe)Cl brines .…”

“…RJB writes -The first in depth study of fluid inclusions in porphyry systems was by Ed Roedder (Roedder, 1971a), who studied inclusions from the Bingham, Utah, and Butte, Montana porphyry Cu-Mo systems, and the Climax, Colorado porphyry moly system. In the paper that resulted from this work, Roedder was remarkably prescient in making observations and interpretations that laid the groundwork for future studies and contributed to the development of a genetic model for these deposits.…”

The Solubility of Tugarinovite (MoO2) in H2O at Elevated Temperatures and Pressures

“…Fluid inclusion studies suggest that Mo deposition usually occurs at temperatures between 450 and about 700 ∘ C and pressures between 100 and 170 MPa [44][45][46][47][48][49][50][51]. Furthermore, Mo is thought to be transported by low to intermediate density, supercritical aqueous fluids [52][53][54][55][56] as mononuclear hydroxy complexes [57][58][59][60][61].…”