Aragonite Vs Calcite Cave Speleothem Buchanan (2025) Aragonite and calcite are both polymorphs of calcium carbonate (CaCO ₃ ), meaning they have the same chemical composition but different crystal structures. Aragonite is commonly found in marine shells, coral skeletons, and cave formations, while calcite is more widespread in sedimentary rocks like limestone, dolomite. In caves, aragonite and calcite both play significant roles in speleothem (cave formation) development, they form under different conditions and exhibit distinct crystal habits. Picture: - Aragonite sprays- Wolkburg Caves, Limpopo, South Africa, Lake chamber (Mike Buchanan) Crystallography of Aragonite · Crystal System: Orthorhombic · Habit: Prismatic, needle-like, or columnar crystals, often forming fibrous or radiating aggregates · Cleavage: D...
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Environmental Impact Report: Acid Mine Drainage, Groundwater Contamination, and Radon Emissions in the Cradle of Humankind Mike Buchanan 2023 Executive Summary This report investigates the significant environmental challenges arising from acid mine drainage (AMD), groundwater contamination, and the emission of radon gas (Rn-222) in the Cradle of Humankind, a UNESCO World Heritage Site. These issues, primarily stemming from abandoned and relic mines in the Gauteng and Northwest Provinces, pose serious risks to public health, ecological integrity, and cultural heritage. The report outlines the geohydrological mechanisms driving contamination and proposes a multi-tiered remediation strategy supported by recent scientific and governmental findings (Naicker et al., 2003; Coetzee et al., 2006; WHO, 2021). 1. Introduction The Cradle of Humankind, a UNESCO World Heritage Site located in Gauteng, faces pressing environmental issues due to ongoing acid mine drainage (AMD...
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The Importance of Carbonates: A Long‑Overdue Anthropogenic Failure in Global Understanding Mike Buchanan – 2025 Carbonate terrains remind us that the foundations of life, culture and civilisation are often shaped not by the dramatic upheavals we readily perceive, but by the quiet, persistent forces that work in darkness and deep time. In the hidden chambers of karst systems, where water, stone, biology and gravity negotiate their ancient dialogue, we see that the world is built through patient transformation, subtle interaction and the continual re-carving of possibility. These landscapes are a testament to the truth that resilience and vulnerability coexist. They nourish societies with water, fertility and passage, yet remain fragile to human disregard. To understand carbonates is to recognise that our existence is intertwined with processes far older and more intricate than ourselves. That wisdom lies in honouring the slow, delicate architectures that have sustained life lo...
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A Geoethical Manifesto: Earth as Judge — A Reckoning with a Laugh We built empires on the dream of endless more. We worshipped speed and scale, crowned growth as virtue, and treated the planet as an infinite ledger to be debited. We fashioned gods of invention and profit, celebrities of extraction and spectacle, who promised salvation in quarterly returns and flagship rockets. We cheered them on, made them our altars and taught our children to measure worth by wealth and mobile viral fame. Now the tenant speaks. The planet does not sermonise. It replies, with heat, flood, wildfire, collapse and silence where song once was. Its verdict is not moral but mathematical: limits exist. Systems that ignore limits do not reform; they fail. And that failure will not be fair. It will be indifferent, ruin distributed without ceremony, falling hardest on those least responsible and least able to escape. Let us admit two truths plainly. First: our economic religion, endless ex...
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The Geoethical Case Against Reservoirs in Karstified Carbonate Terrains: Interdisciplinary Evidence and Policy Guidance – Mike Buchanan 2025 Abstract Karstified carbonate terrains present unique hydrogeological, geomechanical, geochemical and ecological vulnerabilities that render surface and subsurface reservoirs high-risk infrastructure. This paper synthesises multidisciplinary evidence demonstrating why avoidance should be the default policy, clarifies circumstances where rigorous, exceptional mitigation might be considered and proposes operational, monitoring, legal frameworks to protect subterranean ecosystems and downstream stakeholders. Introduction Karst systems Characterised by dissolution conduits, caves, sinkholes, and heterogeneous porosity - exhibit rapid, anisotropic flow and high uncertainty in subsurface geometry (Ford & Williams, 2007). Traditional engineering approaches that assume continuous confining layers or predictable transmissivity are ill...
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A Scientific Position Paper Opposing Further Archaeological Excavation at Gcwihaba Cave, Botswana Mike Buchanan, Karstologist -2025 Abstract This paper presents a formal objection to ongoing and proposed archaeological excavations within the Gcwihaba–Koanaka cave complex, Ngamiland, north-western Botswana. The site represents one of Southern Africa’s oldest, most intact karst ecosystems and functions as a critical bat hibernaculum and paleoenvironmental archive. Recent reports by Laurent Bruxelles, Director of the International Research Center SHARE (CNRS/University of the Witwatersrand), confirming the extraction of more than four tons of fossiliferous sediment from the Koanaka Hills after only one week of excavation (Bruxelles, 2025), reveal an alarming disregard for internationally accepted conservation standards. Such activities threaten irreversible ecological, geological and heritage damage and contravene Botswana’s Monuments and Relics Act (2001) as well as the prin...
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Geological Relationships Among the Barberton Greenstone Belt, Black Reef Quartzites, Limpopo Banded Iron Formation, and Malmani Subgroup Buchanan 2024 Abstract This paper explores the geological relationships among the Barberton Greenstone Belt, Black Reef Quartzites, Limpopo Banded Iron Formation (BIF), and Malmani Subgroup in South Africa. It provides a timeline of their formation, highlighting the transitions in depositional environments and the significance of these formations in understanding early Earth processes. 1. Introduction The geological history of South Africa is marked by significant formations that provide insights into the early Earth. This paper examines the relationships among the Barberton Greenstone Belt, Black Reef Quartzites, Limpopo BIF, and Malmani Subgroup, focusing on their ages and depositional contexts. 2. Geological Context and Timeline 2.1 Barberton Greenstone Belt The Barberton Greenstone Belt is one of the oldest geological formati...