Determination of Soil Contamination at the Wildland-Urban Interface after the 2021 Marshall Fire in Colorado, USA.

Wildfires at the wildland-urban interface (WUI) are increasingly common. The impacts of such events are likely distinct from those that occur strictly in wildland areas, as we would expect an elevated likelihood of soil contamination due to the combustion of anthropogenic materials. We evaluated the impacts of a wildfire at the WUI on soil contamination, sampling soils from residential and nonresidential areas located inside and outside the perimeter of the 2021 Marshall Fire in Colorado, USA.

The Montecristo mining district, northern Chile: the relationship between vein-like magnetite-(apatite) and iron oxide-copper-gold deposits.

Unlabelled: The Montecristo district, northern Chile, is one of the few places worldwide where there is a direct relationship between magnetite-(apatite) (MtAp) mineralization and iron oxide-copper-gold (IOCG) mineralization. The MtAp mineralization includes Ti-poor magnetite, fluorapatite, and actinolite and is crosscut and partially replaced by a younger IOCG mineralization that includes a second generation of actinolite and magnetite with quartz, chalcopyrite, pyrite, and molybdenite. The MtAp stage at Montecristo is interpreted as the crystallized iron-rich melts that used the pre-existing structures of the Atacama Fault System as conduits.

Pretreatment of Nitric Acid with Hydrogen Peroxide Reduces Total Procedural Os Blank to Femtogram Levels.

Determining and correcting for background contributions of Re and Os from chemical reagents is critical for accurate and precise Re-Os dating of materials with parts per billion to parts per trillion Re and Os concentrations. Here we investigate reducing Os content in nitric acid, as it is the main contributor to the Os blank. Pretreating high-purity nitric acid with hydrogen peroxide (H2O2) significantly reduces nitric acid's Os contribution to femtogram levels, greatly reducing Os blank corrections.

4-(3-Methoxy-phen-yl)-2,6-dimethyl-cyclo-hex-3-enecarboxylic acid.

The racemic title compound, C(16)H(20)O(3), was synthesized to study the hydrogen-bonding inter-action of the two enanti-o-mers in the solid state. In the crystal structure, R and S pairs of the racemate are linked by pairs of inter-molecular O-H⋯O hydrogen bonds, producing centrosymmetric R(2) (2)(8) rings.

2,6-Dimethyl-4-m-tolyl-cyclo-hex-3-enecarboxylic acid.

The title compound, C(16)H(20)O(2), was synthesized to study the hydrogen-bonding inter-action of the two enanti-omers in the solid state. The racemate is made up of carboxylic acid RS dimers. Inter-molecular O-H⋯O hydrogen bonds produce centrosymmetric R(2) (2)(8) rings which dimerize the two chiral enanti-omers through their carboxyl groups.