How Gold Nuggets Form: The Role of Earthquakes
A longstanding mystery surrounding the geological formation of gold nuggets has been elucidated. New research reveals that electricity and frequent earthquakes chiefly contribute to this phenomenon, reports National Geographic.
Gold is highly sought after. Presently, gold nuggets are not challenging to find, as much of the world's gold derives from quartz veins. Quartz — a mineral ingrained in Earth's crust — holds the mystery of gold nugget formation. Recent findings published in Nature Geoscience provide surprising insights into this process.
The intriguing charge properties of quartz aid in forming gold nuggets. When quartz undergoes pressure or vibration, it generates electricity, extracting gold particles from fluids within spacious cracks of the crust. Over time, as electrification continues, these particles crystallize into larger nuggets.
Christopher Voisey, a lead geologist at Monash University, emphasizes this connection, stating, "If you shake quartz, it makes electricity. If you create electricity, gold comes out." Earthquakes likely produce the necessary shaking to facilitate this process, according to lab experiments confirming their vital role in nugget creation.
Geological Context of Gold Nuggets
Gold typically populates quartz veins amid a backdrop of intense geological activity. From a distance, quartz appears like vibrant cobwebs woven through rugged rock, defining where gold-bearing deposits are found. These veins emerge from areas subjected to significant strain during tectonic events, such as mountain formation.
Fault lines riddled within these stressed areas become channels for heated geologic fluids, often rich with gold particles from fractures during earthquakes. "Thousands to tens of thousands of fluid pulses bring in gold," explains Voisey, leading to significant gold deposits in quartz settings.
Although it isn’t surprising that gold particles linger in quartz, witnessing large nuggets isolated within these veins proves puzzling. Iain Pitcairn, an ore geologist at Stockholm University, highlights the anomaly: "How do you get such massive concentrations of gold in quartz veins?" The answer to this riddle lies in specialized geological processes.
Unusual Properties of Quartz
Quartz is notably unique as a mineral, composed solely of silicon and oxygen. Substantial discrepancies in its crystal symmetry induce inherent electrical imbalances, allowing it to produce electricity under certain conditions. When pressure is applied, quartz develops an electric field.
This process, termed piezoelectricity, underscores why quartz holds such potential for gold deposition. Voisey points out, "The more force applied, the higher the electrical response." If quartz experiences extreme force — and shatters — the resulting voltage is maximized.
Voisey initially found the correlation between quartz's piezoelectric nature and gold nugget existence to be improbable. However, in his view, it turned out to be a perfect coincidence leading to groundbreaking conclusions.
Experimental Validation of the Theory
To test the hypothesis of earthquakes contributing to gold nugget formation, Voisey’s team conducted experiments using natural quartz slabs situated within gold-bearing liquids. While some slabs vibrated to simulate earthquake effects, others remained motionless as controls. The goal was to tap into the onset of gold crystallization during physical manipulation.
After the trial, Voisey's micrometer measurements revealed wondrous results: numerous gold particles glimmered atop the surfaces of vibrated slabs. After establishing the correlation between movement and gold deposition, Voisey felt ecstatic.
He later explored how this process facilitates larger nugget formation rather than mere flecks. Another quartz piece contained a small nugget, which grew significantly after the machine's tremors; pre-existing particles served as anchors drawing additional gold from the surrounding solution — becoming "lightning rods," as Voisey explains.
Multiple Earthquake Interactions
Natural events likely do not catalyze nuggets from a single shift. Instead, a medley of earthquakes progressively nurtures crystal growth. Each sequential quake aids in further crystallizing gold atop existing grains, ultimately giving rise to nuggets.
Pitcairn acknowledges the elegance of this finding, affirming its novelty. Historically, gold's spontaneous generation from quartz subjected to stress would seem miraculous — a feat of alchemy. This research underscores nature’s remarkable workings and reveals the intriguing simplicity underlying gold nugget formation.
"It’s almost too neat, too tidy," states Voisey, pleased with the clarity achieved in unveiling this natural process.
Earlier, SSP reported that digging holes at the beach can be dangerous.
