Nucleosynthesis of gold starts with atoms of iron which were formed by fusion within the core of a star. All elements in the universe with more than 26 protons in their nucleus (i.e, “heavier” than iron) were created through neutron capture processes, when neutrons are forced into the nucleus of an atom within a star.
In the subsequent radioactive decay process, a beta particle (electron/positron) is emitted from that neutron. The neutron is converted into a proton by that beta decay, and an atom of an element with one higher atomic number is formed.
Nearly all gold atoms were created very quickly in what physicists called the r-process, for with “r” for “rapid” nucleosynthesis. It is possible that some gold atoms formed in the s-process (“s” for “slow”), just before an old star becomes a white dwarf.
Assuming the atoms of gold found in Virginia today were formed originally by the rapid nucleosynthesis process, then Virginia’s gold deposits started with the collision of two neutron stars to create a kilonova or when the nickel-iron core collapsed in a Type II supernova. Those supernovae are high-energy explosions of fast-spinning stars with a strong magnetic field.
In an initial pressure cooker phase leading to a supernova, the star’s core collapses. The pressure compresses atomic particles together faster than radioactive decay splits the nuclei apart, and forcing a proton into a nucleus is one way a star creates a new element. Almost immediately, in the second phase a violent explosion expels the newly-formed elements into a gaseous cloud.
In the alternative kilnova process, neutron star mergers within 1,000 light-years of our solar system could have created a high percentage of the heavy elements that coalesced and formed Earth and the other planets in our solar system. A merger of two neutron stars could create 13,170,000,000,000,000,000,000,000 (13 septillion) pounds of gold – or even 13 times that total.
Perhaps 80 million years before the formation of our solar system, which occurred 4.6 billion years ago, the dramatic end of two neutron stars disseminated gold and other heavier-than-iron elements atoms into space. Those elements then accumulated in gas clouds via gravitational forces, and were incorporated into new stars, asteroids and planets.
All gold on earth came from outer space, and the gold atoms may have formed when two neutron stars collided.
Despite the dreams of midieval alchemists who sought to transform lead into gold, all the gold on earth is older that the formation of the earth itself. All gold on earth originally came from outer space. In contrast, the diamonds found on earth were created here within the last 4.6 billion years. The carbon within diamonds also pre-dates the formation of earth. Since the planet formed, intense pressures have altered the alignment of carbon atoms into the crystalline form to create diamonds.
The process for creating heavier-than-iron atoms is still being debated. A 2020 scientific study concluded that the frequency of neutron star collisions was too low to create all the gold identified today. In addition to star collisions, magnetorotational supernovae could have forced protons into nuclei to create the elements beyond gold in the Periodic Table of Elements.
The Gold-Pyrite Belt in the Piedmont physiographic province is a zone of mineralization 15-25 miles wide, east of the Blue Ridge and stretching all the way between the Potomac River and Buckingham County. Gold is also found in the Virgilina District of the Carolina Slate Belt, south of the James River. Some of the original deposition of gold in the Virgilina District occurred about 650 million years ago, with a major influx of gold mineralization 550 million years ago. Gold deposits in the Gold-Pyrite Belt north of the James River probably formed 550 million years ago.
Over the last 4.6 billion years, those gold molecules have moved within the mantle and crust. The gold found in Virginia today can be traced back to the time volcanic islands and chuncks of continental crust formed in the Iapetus Ocean, before they were accreted to the continental crust and created the supercontinent of Pangea. Those island arcs were on the western edge of Gondwana.
In the formation of Pangea, subduction of crust led to melting and differentiation of different minerals within the magma. The gold in today’s Piedmont bedrock may have been remobilized roughly 450-250 million years ago, between the Taconic and Alleghenian orogenies. The accretion of the Potomac Terrane formed between 500-470 million years ago, followed by the younger Chopawamsic Terrane formed between 474-465 million years ago, may have brought pre-existing gold deposits to Virginia.
It is also possible that the gold deposits in places such as Orange County were formed during the collision of tectonic chunks of crust:
- The gold is believed to have formed in submarine hot spring environments, where mineral-bearing waters pooled in topographic lows.
Gold and quartz, which melted at similar temperatures, flowed into fractures parallel to thrust faults. As the mass of molten rock slowly cooled below 1,943°F, gold molecules shifted from a liquid to a solid state and “froze” or crystallized in place.
Most of the molten gold crystallized within bedrock while still buried miles underground. Some vaporized gold could have been emitted from volcanoes as fine particles with volcanic ash, and formed ancient placer deposits on the surface of the island or on the Iapetus Ocean seafloor nearby. As terranes were accreted to the edge of the North American Plate, such surface deposits would have been scattered by erosion while subsurface gold near hot springs was concentrated into ore bodies. Molecules of gold have cycled and been recycled into different locations over time.
Much of the Virginia gold may have been melted and moved (mobilized) during the Taconic, Neo-Acadian, and Alleghenian orogenies. Under heat and pressure, the gold originally contained within volcanic islands was squeezed along with silica (quartz) into the veins now scattered within the metamorphosed bedrock of the Virginia Piedmont.
Underneath ore deposits at the surface may be funnel-shaped feeder zones connecting to magmatic roots. Low-grade disseminated gold deposits at the surface identify where exploration geologists might discover high-grade feeder zones. Deep drilling can identify if there is sufficient gold-rich ore at depth to justify the expense of creating an open-pit mine in Virginia, similar to the Haile mine in South Carolina.
Geologists studying the Carolina Slate Belt deposits concluded that gold deposition occurred over several hundred thousand years. Some deposits formed within 50,000 years, where the magma source cooled without renewal from the heat source. There were different ore-forming environments for each deposit, and:3
- … the gold mineralization is about the same age as the enclosing rocks, rather than younger. Lead isotopic variations of the major gold deposits in the slate belt also show that the gold was remobilized after its initial deposition…
- Fluid-inclusion data suggest that water-dominated fluids associated with the different styles of mineralization had a wide range of temperatures and contents of salt. Results indicate that during gold deposition in some deposits, gases were lost (for example, carbon dioxide), and that mixing of different types of water-rich fluids was necessary before gold precipitated; data for other deposits support a model of mixing of seawater and hydrothermal fluids.
Some veins may be even younger than the Alleghenian orogeny, and date from the time when Pangea split up about 225 million years ago. Triassic basins developed when the crust thinned. Earthquakes were a common occurrence as blocks of crust moved at faults moved. The sediments in the basins tilted and molten basalt at great depth jetted through cracks to the surface. When the pressure of the overlying rock was released briefly during earthquakes, other fluids may also have boiled up towards the surface, squeezing through cracks in the surrounding rock.
When silica cooled back into hard rock, it formed new quartz veins within the fractures through which the liquid had moved. At the Vaucluse Mine in Orange County, gold was found mixed with “rose” quartz (colored by iron oxide) and sericite formed when feldspars were altered by hydrothermal fluids.
In those locations where gold had been a component of the molten fluids at depth, those quartz veins included gold deposits. Molten sulfur was also common in those hydrothermal fluids, so crystals of iron sulfide (FeS2) are also found along with gold ore. The glint of iron sulfide crystals has led to is common name, “fool’s gold.”
The gold may have been carried in the hydrothermal liquid as nanoparticles that formed a colloid, comparable to how proteins and fats are suspended within milk. When the high concentration of suspended gold nanoparticles finally crystallized as the hydrothermal liquid cooled, thick gold veins were created.
Gold simply dissolved in hot fluids, rather than suspended in a colloid, could also crystallize into deposit. The tiny particles which crystallized would create very thin layers of gold, rather than the thick veins with nuggets cherished by gold prospectors. Tiny particles can be extracted commercially today, especially from volcanic deposits where gold literally erupted as a tiny percentage of the material in ash clouds. The ash is heaped into a pile, and then a fluid with cyanide is poured on top. As the fluid flows through the heap, gold dissolves into it. The final step is extracting the gold from the “pregnant liquor,” after which the cyanide can be reused.
The earliest English settlers of the Virginia Company were looking for gold. Gold equals wealth, at least to humans. The richest man in the history of the world was been the ruler of Mali, Mansa Musa. In the early 1300’s, he controlled more wealth than any other human who has ever lived because Mali produced most of Africa’s gold. It was the major source of gold for Europe until the discovery of the New World.5
The Spanish seized vast amounts of gold from Aztec, Inca, and other Native American societies in Central and South America. The English started their colonization efforts about a century later, and targeted North America to avoid conflict with existing Spanish settlements. In Virginia and then later colonies, the English did not discover any native societies in North America that had mined and accumulated gold. The gold discovered by the English within Native American communities along the East Coast had been acquired from shipwrecks or exchange with early Spanish and French settlers.
The first gold rush in the United States occurred in North Carolina, nearly two centuries after Jamestown was settled. In 1799, a 12-year old boy found a heavy rock with a yellow color near the site of modern Charlotte. The family used it as a doorstop until 1802, when a North Carolina jeweler bought the rock for $3.50. After he revealed the doorstop was a 17 pound gold nugget, the gold rush began in the western North Carolina Piedmont. Initial mining depleted placer deposits, where gold had accumulated in streambeds. In 1825, miners began digging in the ground to extract gold from lode deposits, where it was mixed with quartz in veins.
Thomas Jefferson documented the first gold discovered within Virginia:
- I knew a single instance of gold found in this state. It was interspersed in small specks through a lump of ore, of about four pounds weight, which yielded seventeen penny-weight of gold, of extraordinary ductility. This ore was found on the North side of Rappahanock, about four miles below the falls. I never heard of any other indication of gold in its neighbourhood.
That lump of ore would have washed down from its original location in the Piedmont, past the Fall Line at Fredericksburg, before settling with other sediments in a placer deposit on the Coastal Plain. Jefferson’s handwritten version of Notes on the State of Virginia suggests he had heard of gold in the Piedmont physiographic province, but he edited out information about Gold Mine Creek before publication.
