Amazed at the strange thing in China’s giant gold mine

An international team of scientists has discovered that a gold mine The giant giant in northern China was formed by liquid magma mixing with rainwater, a process unlike that of gold found elsewhere in the world, SCMP reported.

The researchers say their findings could help with the search for gold resources by identifying areas that show magmatic activities originating from the past mantle-forming of cavitation rock similar to those found in the mines. Dongping gold, located on the crater of northern China.

Scientists have long thought that gold deposits form when hot water flows through rock, dissolving small amounts of gold and concentrating in cracks in the Earth’s crust to levels invisible to the naked eye.

The long-accepted notion that gold is transported by liquid route through the Earth’s crust and that gold is created by water and earthquakes. Earthquakes create countless openings, which quickly fill with water. In conditions tens of kilometers underground, where pressure and temperature are extremely high, the necessary substances such as carbon dioxide, silicon dioxide and others will help create gold. Then after an aftershock or other earthquake causes the gap to widen and the pressure drop suddenly, the water evaporates and the gold particles present in the liquid precipitate immediately.

LIVE China“the world-class Dong Binh gold mine was formed by multiple pulses of hydrothermal magma fluid mixed with large volumes of rainwater” – according to the research team.

Pulses of magma liquid continuously emanate from the magma chamber below. The cracks and faults act as conduits, allowing magmatic fluids to ascend and then mix with rainwater, a process that leads to gold deposition.

According to the authors, this study opens the door to understanding the origins of worldwide gold veins and other hydrothermal systems that may have created huge gold deposits in the Earth’s crust.

The researchers – from the China University of Geosciences, the Chinese Academy of Sciences, the University of Wisconsin – Madison in the US and the German Geosciences Research Center – published their findings in the journal Proceedings of the National Academy of Sciences.

Much of northern China – including what is now Beijing, Tianjin, and around Hebei province – lies in part of the lithosphere (the hardest outermost crust of the terrestrial planets), called “craton”, which in Greek means strength.

One of the authors, Li Jianwei, dean and professor at the school of soil resources at China University of Geosciences in Wuhan, said that although the liquid source and gold formation process in the Dongping mine are different with other craters in the world, but the composition of this precious metal shows no fundamental difference.

The gold mines in China are much younger than those in other craters around the world, he added. While the gold deposits in other craters mainly formed between 1.8 and 2.8 billion years ago, the crater gold deposits in northern China formed about 140 to 120 million years ago. .

The northern China crater, 1.5 million square kilometers wide, is one of the world’s oldest deposits and a rich source of ancient rock for geologists.

The team said they used “secondary ion mass spectrometry” to analyze the oxygen isotope composition of garnet, a mineral that can retain isotopic signatures of the liquid that forms it at magma temperatures. .

They found that the ore liquid most likely originated from the degassing of an underlying magma chamber, while water from rain and snow has been involved in ore precipitation throughout mineralization history.

The team says the analysis of the garnet could be used to trace the origin and evolution of other huge hydrothermal ore deposits in the crust. The earth.