Скачать или смотреть The Richest Goldfield on Earth Worth $13 Trillion

#southafrica #gold #goldmining
The Witwatersrand Basin in South Africa is the richest gold province on Earth, responsible for around 48,000 tonnes of gold mined since 1886, nearly forty percent of all gold ever produced in human history. In this video, I explore why this extraordinary deposit is so different from almost every other goldfield on the planet, and why its riches were not locked in classic quartz veins, but in ancient river gravels that were later buried, hardened, and transformed into rock. The story of the Witwatersrand is a deep-time tale of geology, tectonics, metamorphism, and even a massive asteroid impact that reshaped the landscape without being the true source of the gold.

Most people imagine gold deposits as narrow hydrothermal veins cutting through hard bedrock, like those found in Kalgoorlie, Bendigo, or the Victorian goldfields. The Witwatersrand flips that idea completely. Its famous “reefs” are actually fossil river channels made of quartz pebble conglomerate, laid down in the Archaean nearly three billion years ago across the ancient Kaapvaal Craton. These alluvial layers concentrated gold mechanically through flowing water, much like modern placer systems, before being buried kilometres beneath the surface and metamorphosed into solid rock that later had to be blasted, crushed, and milled by miners.

What makes the Witwatersrand even more fascinating is that the gold was not simply left untouched after deposition. Regional greenschist facies metamorphism, large-scale thrust faulting, and the movement of hot, gold-bearing fluids all played a role in upgrading and redistributing the metal within specific reef horizons. Carbon-rich seams and iron-bearing minerals acted as chemical traps, helping to lock gold into the most prospective layers along ancient unconformity surfaces. Structural deformation created fracture networks that controlled fluid flow, explaining why high-grade zones often align with thrust-related permeability rather than simple sedimentary layering.

Around two billion years ago, the Vredefort asteroid impact struck the region, forming the largest preserved impact structure on Earth. While this event did not create the Witwatersrand gold, it dramatically altered the crust, increased fracturing, and generated secondary permeability that allowed further local remobilisation of gold. The impact left a powerful geological overprint that adds another layer of complexity to an already extraordinary system, but the true origin of the gold remains tied to ancient rivers, deep burial, and later fluid-driven modification.

This video unpacks the geology, mining history, and scientific debates surrounding the Witwatersrand, from placer versus hydrothermal models to the role of metamorphism, structure, and impact processes. It explains why this basin became the greatest gold province ever discovered, how its deposits were preserved through billions of years of Earth history, and why it continues to shape our understanding of Archaean environments, ore formation, and the evolution of the early atmosphere.

Studies Used To Construct This Video:
Witwatersrand Gold Fields: Geology, Genesis, and Exploration:
https://pubs.geoscienceworld.org/segw...

Archaean atmospheric evolution: evidence from the Witwatersrand gold fields, South Africa:
https://www.sciencedirect.com/science...

Origin of Witwatersrand gold: a metamorphic devolatilisation–hydrothermal replacement model:
https://www.tandfonline.com/doi/abs/1...

Metamorphism of the Witwatersrand gold fields: A review:
https://www.sciencedirect.com/science...

Structural controls on Witwatersrand gold mineralisation:
https://www.sciencedirect.com/science...

Recent Developments Concerning the Geological History and Genesis of the Witwatersrand Gold Deposits, South Africa:
https://pubs.geoscienceworld.org/segw...

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The core mission of OzGeology is to make geology exciting, accessible, and inspiring for everyone. Instead of presenting rocks and earth science as dry or overly academic, OzGeology brings stories of the planet to life, revealing how every mountain, mineral, and landscape tells part of Earth’s grand adventure. The goal is to help people see the world differently, to understand the dynamic forces shaping Australia and beyond, and to spark curiosity in the next generation of geologists. Through engaging storytelling, field exploration, and clear explanations, OzGeology turns the study of our planet into a journey of discovery rather than a classroom lecture.