In aquifers subject to saline water intrusion, the mixing zone between freshwater and saltwater displays strong physico-chemical gradients. Although the microbial component of these specific environments has been largely disregarded, the contribution of micro-organisms to biogeochemical reactions impacting water geochemistry has previously been conjectured. The objective of this study was to ch...

Geochemical studies and surveys conducted by the Geological Survey of Canada have provided considerable information about the natural geochemical variations in glacial drift, lake sediments, and lake waters in south-central District of Keewatin. In addition to their intended contribution to mineral exploration, these activities yielded much basic background data that may be applied to the plann...

Biomineralization marks one of the most significant evolutionary milestones among the Eukarya, but its roots in the fossil record remain obscure. We report crystallographic and geochemical evidence for controlled eukaryotic biomineralization in Neoproterozoic scale microfossils from the Fifteenmile Group of Yukon, Canada. High-resolution transmission electron microscopy reveals that the microfo...

Extreme habitats lie outside the range of conditions in which most of organisms live. 'Extreme' includes physical extremes, e.g. temperature, radiation, pressure, and geochemical extreme, for example desiccation, salinity, pH, depletion of oxygen or extreme redox potential. Investigations of these environments are important for the study of evolution relationships, emergence of new species and ...

The Aquificales are thermophilic microorganisms that inhabit hydrothermal systems worldwide and are considered one of the earliest lineages of the domain Bacteria. We analyzed metagenome sequence obtained from six thermal "filamentous streamer" communities (∼40 Mbp per site), which targeted three different groups of Aquificales found in Yellowstone National Park (YNP). Unassembled metagenome se...

Geochemical modeling of magma mixing allows for evaluation of volumes of magma storage reservoirs and magma plumbing configurations. A new analytical expression is derived for a simple two-component box-mixing model describing the proportions of mixing components in erupted lavas as a function of time. Four versions of this model are applied to a mixing trend spanning episodes 3–31 of Kilauea V...

Surface geological and geochemical mapping have been key technical contributors to many gold discoveries over the past 25 years. However, in the last ten years there has been a growing emphasis on using geophysical techniques to compliment them in covered terrains. As the search for gold deposits under covered areas expands, there will be increasing emphasis on integrating the geoscientific dis...

A multi-component reactive transport model, coupled to an existing thermal, hydraulic and mechanical model is investigated. The model is based on conservation of mass/energy principles for the flow and stress strain equilibrium for the mechanical behaviour. The resultant model is coupled to a geochemical model in order to capture geochemical interactions. Numerically, the Galerkin finite elemen...

Bivalve shells can provide excellent archives of past environmental change but have not been used to interpret ocean acidification events. We investigated carbon, oxygen and trace element records from different shell layers in the mussels Mytilus galloprovincialis combined with detailed investigations of the shell ultrastructure. Mussels from the harbour of Ischia (Mediterranean, Italy) were tr...