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Iron (oxyhydr)oxide concretions in the Navajo Sandstone of southern Utah have been extensively researched as Martian analogues. However, the discovery of calcium carbonate concretions in areas such as Coyote Gulch, Utah, has encouraged recent studies to understand the relationship between calcium carbonate spheroidal concretions as possible precursors to iron (oxyhydr)oxide concretions, and to determine the fluid chemistries involved in diagenesis. This is important because nucleation and precipitation mechanisms of these spheroidal calcium carbonate and iron (oxyhydr)oxide concretions and fluid mechanisms in iron rich environments could affect the preservation of possible biosignatures in other subsurface features on Mars. The elemental and mineralogical compositions of the concretions were examined in order to determine physical and chemical features shared by the two types of concretions and did show that they share similar morphologies; however, the Coyote Gulch concretions are calcite cemented (~30 wt.%), with secondary iron (oxyhydr)oxide precipitation and decreases in calcite in transects away from the calcium carbonate concretions. Several chemical and mineralogical differences exist between the two separate populations of concretions, possibly due to regional variability of reacting phases in fluid systems. Spring fluids emanating from the Navajo Sandstone in Coyote Gulch were tested to determine the fluids responsible for the development of any of the concretion mineralogies in the study area which could form in distinctive geochemical systems. Geochemical modeling performed in this research explored the question of fluid chemistry involved in concretion formation in the Navajo Sandstone and findings suggest that the calcite concretions formed prior to the precipitation of secondary iron (oxyhydr)oxides and may have provided a localized buffering environment for the precipitation of iron (oxyhydr)oxides. Paleofluid circulation, redox processes, and elemental mobility are examined using the geochemistry of Navajo Sandstone concretions and host rock. Various simulations applicable to diagenetic fluids in the studied concretions show the importance of salinity and pH in paleoaquifers in order to precipitate mineral assemblages similar to those found in the Navajo Sandstone. Widespread dissolution features, major and trace element distributions, and geochemical modeling identified feasible fluid-rock interactions in paleofluids, including the importance of limited H2S gas and the limited feasibility of hydrocarbon rich fluids in concretion formation using current data. A universal mechanism for calcium carbonate to iron (oxyhydr)oxide concretion formation could be applied on other planets and provide exciting implications in the search for carbon rich redox gradients which could support life in the subsurface of otherwise inhospitable planets.

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Yes / The process of capturing and storing carbon dioxide (CCS) was previously considered a crucial and time-sensitive approach for diminishing CO2 emissions originating from coal, oil, and gas sectors. Its implementation was seen necessary to address the detrimental effects of CO2 on the atmosphere and the ecosystem. This recognition was achieved by previous substantial study efforts. The carbon capture and storage (CCS) cycle concludes with the final stage of CO2 storage. This stage involves primarily the adsorption of CO2 in the ocean and the injection of CO2 into subsurface reservoir formations. Additionally, the process of CO2 reactivity with minerals in the reservoir formations leads to the formation of limestone through injectivities. Carbon capture and storage (CCS) is the final phase in the CCS cycle, mostly achieved by the use of marine and underground geological sequestration methods, along with mineral carbonation techniques. The introduction of supercritical CO2 into geological formations has the potential to alter the prevailing physical and chemical characteristics of the subsurface environment. This process can lead to modifications in the pore fluid pressure, temperature conditions, chemical reactivity, and stress distribution within the reservoir rock. The objective of this study is to enhance our existing understanding of CO2 injection and storage systems, with a specific focus on CO2 storage techniques and the associated issues faced during their implementation. Additionally, this research examines strategies for mitigating important uncertainties in carbon capture and storage (CCS) practises. Carbon capture and storage (CCS) facilities can be considered as integrated systems. However, in scientific research, these storage systems are often divided based on the physical and spatial scales relevant to the investigations. Utilising the chosen system as a boundary condition is a highly effective method for segregating the physics in a diverse range of physical applications. Regrettably, the used separation technique fails to effectively depict the behaviour of the broader significant system in the context of water and gas movement within porous media. The limited efficacy of the technique in capturing the behaviour of the broader relevant system can be attributed to the intricate nature of geological subsurface systems. As a result, various carbon capture and storage (CCS) technologies have emerged, each with distinct applications, associated prices, and social and environmental implications. The results of this study have the potential to enhance comprehension regarding the selection of an appropriate carbon capture and storage (CCS) application method. Moreover, these findings can contribute to the optimisation of greenhouse gas emissions and their associated environmental consequences. By promoting process sustainability, this research can address critical challenges related to global climate change, which are currently of utmost importance to humanity. Despite the significant advancements in this technology over the past decade, various concerns and ambiguities have been highlighted. Considerable emphasis was placed on the fundamental discoveries made in practical programmes related to the storage of CO2 thus far. The study has provided evidence that despite the extensive research and implementation of several CCS technologies thus far, the process of selecting an appropriate and widely accepted CCS technology remains challenging due to considerations related to its technological feasibility, economic viability, and societal and environmental acceptance.