Publications by authors named "Michael Verrall"

Article Synopsis
  • This study examines 3.48 billion-year-old pyritic stromatolites from the Dresser Formation, revealing distinct structures influenced by hydrothermal activity and microbial processes.
  • The findings indicate a complex interplay between microbial life and sediment deposition, with evidence of organomineralization that suggests the presence of ancient microbial communities.
  • The research implies diverse growth environments for these stromatolites, from shallow waters to brine pools, influenced by both phototrophic and chemotrophic organisms, as indicated by stable isotope data and metal accumulations.
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Texture stands as a fundamental descriptor in the realms of geology and earth and planetary science. Beyond offering insights into the geological processes underlying mineral formation, its characterization plays a pivotal role in advancing engineering applications, notably in mining, mineral processing, and metal extraction, by providing quantitative data for predictive modeling. Laboratory diffraction contrast tomography (LabDCT), a recently developed 3D characterization technique, offers nondestructive measurement of grain phases including their morphology, distribution, and crystal orientation.

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Understanding how minerals are spatially distributed within natural materials and their textures is indispensable to understanding the fundamental processes of how these materials form and how they will behave from a mining engineering perspective. In the past few years, laboratory diffraction contrast tomography (LabDCT) has emerged as a nondestructive technique for 3D mapping of crystallographic orientations in polycrystalline samples. In this study, we demonstrate the application of LabDCT on both chromite sand and a complex chromitite sample from the Merensky Reef (Bushveld Complex, South Africa).

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Biological activity at deep-sea hydrothermal chimneys is driven by chemotrophic microorganisms that metabolize chemicals from the venting high-temperature fluids. Understanding taphonomy and microbial microtextures in such environments is a necessity for micropaleontological and palaeoecological research. This study examines fossilized microorganisms and related microtextures in a recent black smoker from the Roman Ruins hydrothermal vent site, Eastern Manus Basin offshore of Papua New Guinea.

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We have previously used surface chemistry analysis techniques to optimize the functionalization of carbonate rocks with a silylated polyacrylamide-based relative permeability modifier (RPM). The RPM is expected to selectively reduce the permeability to water in a hydrocarbon reservoir setting, resulting in a reduction in the amount of produced water while maintaining the production of oil/gas. This study will focus on using core flooding techniques with brine/crude oil under reservoir conditions (i.

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Observations and modeling studies have shown that during CO injection into underground carbonate reservoirs, the dissolution of CO into formation water forms acidic brine, leading to fluid-rock interactions that can significantly impact the hydraulic properties of the host formation. However, the impacts of these interactions on the pore structure and macroscopic flow properties of host rock are poorly characterized both for the near-wellbore region and deeper into the reservoir. Little attention has been given to the influence of pressure drop from the near-wellbore region to reservoir body on disturbing the ionic equilibrium in the CO-saturated brine and consequent mineral precipitation.

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Preparation of high-quality polished sample surfaces is an essential step in the collection of microanalytical data on the microstructures of minerals and alloys. Poorly prepared samples can yield insufficient or inconsistent results and, in the case of gold, potentially no data due to the "beilby" layer. Currently, preparation of ore samples is difficult as they commonly contain both hard and soft mineral phases.

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The aim of this study was to determine specific distribution of metals in the termite Tumulitermes tumuli (Froggatt) and identify specific organs within the termite that host elevated metals and therefore play an important role in the regulation and transfer of these back into the environment. Like other insects, termites bio-accumulate essential metals to reinforce cuticular structures and utilize storage detoxification for other metals including Ca, P, Mg and K. Previously, Mn and Zn have been found concentrated in mandible tips and are associated with increased hardness whereas Ca, P, Mg and K are accumulated in Malpighian tubules.

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