Accelerating microbial iron cycling promotes re-cementation of surface crusts in iron ore regions.

Accelerating microbial iron cycling is an innovative environmentally responsible strategy for mine remediation. In the present study, we extend the application of microbial iron cycling in environmental remediation, to include biocementation for the aggregation and stabilization of mine wastes. Microbial iron reduction was promoted monthly for 10 months in crushed canga (a by-product from iron ore mining, dominated by crystalline iron oxides) in 1 m containers.

Biocement stabilization of an experimental-scale artificial slope and the reformation of iron-rich crusts.

Novel biotechnologies are required to remediate iron ore mines and address the increasing number of tailings (mine waste) dam collapses worldwide. In this study, we aimed to accelerate iron reduction and oxidation to stabilize an artificial slope. An open-air bioreactor was inoculated with a mixed consortium of microorganisms capable of reducing iron.

Characterisation of iron oxide encrusted microbial fossils.

Robust methods for the characterisation of microbial biosignatures in geological matrices is critical for developing mineralogical biosignatures. Studying microbial fossils is fundamental for our understanding of the role microorganisms have played in elemental cycling in modern and ancient environments on Earth and potentially Mars. Here, we aim to understand what promotes the fossilisation of microorganisms after the initial stages of biomineralisation, committing bacteriomorphic structures to the geological record within iron-rich environments.

Biogeochemical cycling of iron: Implications for biocementation and slope stabilisation.

Microbial biofilms growing in iron-rich seeps surrounding Lake Violão, Carajás, Brazil serve as a superb natural system to study the role of iron cycling in producing secondary iron cements. These seeps flow across iron duricrusts (referred to as canga in Brazil) into hydraulically restricted lakes in northern Brazil. Canga caps all of the iron ore deposits in Brazil, protecting them from being destroyed by erosion in this active weathering environment.

Microbial Diversity in Actively Forming Iron Oxides from Weathered Banded Iron Formation Systems.

The surface crust that caps highly weathered banded iron formations (BIFs) supports a unique ecosystem that is a post-mining restoration priority in iron ore areas. Geochemical evidence indicates that biological processes drive the dissolution of iron oxide minerals and contribute to the ongoing evolution of this duricrust. However, limited information is available on present-day biogeochemical processes in these systems, particularly those that contribute to the precipitation of iron oxides and, thus, the cementation and stabilization of duricrusts.

Rapid change in drift of the Australian plate records collision with Ontong Java plateau.

The subduction of oceanic plateaux, which contain extraordinarily thick basaltic crust and are the marine counterparts of continental flood-basalt provinces, is an important factor in many current models of plate motion and provides a potential mechanism for triggering plate reorganization. To evaluate such models, it is essential to decipher the history of the collision between the largest and thickest of the world's oceanic plateaux, the Ontong Java plateau, and the Australian plate, but this has been hindered by poor constraints for the arrival of the plateau at the Melanesian trench. Here we present (40)Ar-(39)Ar geochronological data on hotspot volcanoes in eastern Australian that reveal a strong link between collision of the Greenland-sized Ontong Java plateau with the Melanesian arc and motion of the Australian plate.