BCRA online seminar series. Tomorrow!! Monday 2nd October.


New member
Ever seen cave frostwork and wondered how it could possibly have formed?
Tomorrow evening we will welcome George Breley from the University of Akron (USA) who has been studying the key factors driving aragonite frostwork formation. George is going to give a talk about airflow and the potential role of microbes in mediating aragonite precipitation in cave environments, with examples from Wind Cave in South Dakota. This seminar will be held on Zoom on Monday 2nd October at 19:30 BST. For joining instructions follow the link: https://bcra.org.uk/seminars2023.html#join

A more detailed introduction:
Our understanding of the factors that influence carbonate mineralogy is continuously evolving. In caves, minerals can precipitate both inorganically and as a consequence of microbial metabolism. Bacteria alter their environments by producing biofilms, selectively favouring and inhibiting precipitation of certain phases and influencing crystal growth kinetics. This geobiological interplay precludes straightforward assessments of biogenicity with regard to mineral samples. Wind Cave, South Dakota, hosts an abundance of well-preserved frostwork; distinctive aragonitic secondary mineral deposits. The cave offers a valuable site to investigate the environmental parameter set governing mineralization and polymorphism. This study identified key factors driving aragonite frostwork formation, evaluating the potential role of microorganisms as agents of carbonate nucleation, crystallization, and alteration. SEM analysis identified recrystallization features and mineral assemblages of Si and Mg in association with aragonite, suggesting a complex precipitation history yielding multi-aggregate speleothems. Observations revealed signs of surficial bacterial colonization and biofilm coverage, opening up the possibility for a microbial component in the formation of one or more frostwork features. X-ray diffraction showed sequential deposition of calcite, aragonite, and hydromagnesite structures. Airflow monitoring and geochemical analysis were conducted to delineate climatic and kinetic factors, respectively. Understanding the link between inorganic factors and microbiological processes controlling CaCO3 polymorphism is foundational to the development of microbially induced carbonate precipitation (MICP)-dependent biotechnology. This knowledge can be leveraged towards industrial carbonate production and CO2 sequestration (George J. Breley, Hazel A. Barton)