It may seem strange that an area of 2,500 square kilometers south of a small Pacific island could provide four substances that have been used in modern electronic devices for hundreds of years.
Located in the western Pacific Ocean, it is the easternmost island in Japan, Minami Torii Island. Spotted for example in a triangle occupies only one square mile, and due to its peculiar wall-like circumference, most of the island is below sea level. There is nothing else but airports and Japan weather stations. The nearest land is more than 1,000 km away.
However, despite its poor quality, the island is still the key to solving the scarcity of rare earth elements: a treasure trove of rare earth elements.
The place where that treasure is located is still curious. The mine is not on the island. It is located in clay sediment south of the seamount where the island is located, with many fish teeth, scales and bones piled up. Fish fossils are the cradle of rare earth elements.
They piled up so much that Japanese scientists calculated that in an area of 2,500 square kilometers south of the island, the mud could meet the needs of the world's four rare earth elements for hundreds of years. But why? And what will the most important scientists do?
Rare earth elements are a group of chemical elements that occupy the entire gully of the periodic table. Science and technology are in the middle of a technological boom, and rare earth elements are essential for dazzling machines. Many of them allow us to generate or utilize renewable energy.
Every time you buy a TV, smartphone, LED, compact fluorescent light or rechargeable battery, there are also utilities that build wind turbines every time Toyota makes Prius, and some rare earth elements are sprayed inside. They are also used by many medical and military technologies. As a result, the consumption of rare earth elements has doubled over the past decade. Ironically, most of the mines they currently come from are in China, and with that comes the environmental problems of mining.
However, rare earth elements are not actually rare on Earth. Rarely, these elements are found in mineable deposits. Due to their chemical properties, they usually do not aggregate into rare earth minerals in a way that is easy to extract.
In a paper published in Science Reports in June, a team of Japanese scientists attempted to date fish fossils from South Torii Island and a second similar site in the southeastern South Pacific Plateau. Determine its origin and whether there may be more rare earth elements elsewhere.
They used details of the fossils themselves and ratios of isotopes in clays that had previously been plotted over time. They calculated that the fossils were 34.4 million years old, and that their concentration at the foot of South Torii Island was an accidental result of planetary cooling from the Antarctic ice sheet.
About thirty-four million years ago, after warm periods, Antarctica began to form a permanent ice sheet cover. Not so long ago (geologically speaking), South America finally opened up to the glacier passage at the bottom of South America and the southern part of the South Tasman Strait, thus moving freely on the mainland, replacing the land bridge between Tasmania and Antarctica. As carbon dioxide in the atmosphere decreases, this cycle isolates Antarctica from the heat of the hotter air to the north and makes Antarctica colder, creating permafrost.
As a result of the cooling, the water at the bottom of the Antarctic becomes colder and therefore denser. Due to deeper groundwater, it begins to flow northward under warmer, less dense currents. The bottom waters, which once collected and stored nutrients for thousands of years in the slow southern waters, were stirred for the first time in a long time.
When this abundant cold water hits the bottom of a seamount that is large enough, steep and high enough, it is forced to rise. Nutrients pouring into the sunlight-irradiated water drive life. Today, due to the rise of deep water currents, a similar but less intense temperature environment is created around seamounts.
The resulting environment suitable for living organisms lasted for about 100,000 years. When the nutrients stored around Antarctica ran out, it stopped functioning. Meanwhile, as a grim but inevitable result, fish tooth bone fragments and tooth-like scales called fine teeth are deposited at the bottom of the sea.
Junichiro Oda, a biological research institute, believes that fossil phosphates are indeed very good at capturing rare earth elements. In the last 34 million years, fossils have slowly absorbed yttrium, eu, ro, and ter from fluids trapped in mud, and the large surface area of biological bones has enhanced this ability. As a result, the mud contains a large number of rare earth elements, but its content is as high as 20 parts per million. What makes Minami-Torii special is not because it contains fish fossils, nor that these fossils are special in every way, but because a one-off process created by past climate change has led to their massive deposition together.
The Japanese team calculated that there are 16 million tons of rare earth oxides south of Minami Torii Island, and at current consumption rates, these four elements are enough to supply the world for 420-780 years, and the deposit "has the potential to supply these metals to the world." ”
Of course, all this means that Minami Torii Island and Kogen are by no means unique. Theoretically, any Pacific island or seamount is steep and tall enough (at least a few kilometers of rise) and deep enough in the basin (more than 5,000 meters calculated by scientists) to be a relatively small area near the base. There are hundreds of islands and seamounts with proper bathymetry in the Pacific Ocean, and potential targets for scientists' research are mapped in red.
Then, the question becomes how to deal with it. Diversification and massive increases in the supply of rare earth elements on Earth seem to be a staunch supporter. The increase in resources means that we can make more equipment to replace the demand for fossil fuels. And fish fossils are larger than the sediments they are buried in, which makes it relatively easy for them to extract and classify by size, rather than using toxic chemicals as in conventional open-pit mining. Compared to terrestrial rare earths, muds also contain small amounts of radioactive elements such as uranium and or.
But the fish fossils are located at depths of more than three miles, depths that do not yet make commercial mining operations profitable. There is also the question of the consequences of deep-sea mining.
The infamous mining of manganese nodules for littering around the world (notoriously under the pretext of grove explorers trying to salvage Soviet submarines) is currently being carried out for the actual purpose of mining manganese nodules in a sea area.
According to a study published July 31 in Ecology and Evolutionary Trends, the cost of disrupting such a large seabed in this context could be both underestimated and high. They believe the same misconception is likely to plague the calculation of the cost of all deep-sea mining projects.
One could argue that because fish fossils are contained in a relatively small area, the benefits of extracting them outweigh any biological costs. But for many of the same reasons that put fish fossils first, habitats south of seamounts can be valuable biological real estate. And, since humans are not omniscient, and the law of unintended consequences is ironclad, there are likely to be other unexpected costs.
How does all this compare to the costs incurred by continuing to acquire rare earth elements in China or through recent efforts to open new mines in the U.S. or elsewhere? A study published Sept. 1 in Nature Communications discusses the very real possibility that, without careful planning and implementation, surface mining could create threats to biodiversity for renewable energy technologies that could outweigh the benefits of halting climate change. In short, it's complicated.
Mining is not the enemy. Without it, society would not be unable to function. A retired mining engineer retires that every commodity we come into contact with is sourced or cultivated, just like agriculture or fishing, and what matters is how we mine. Unfortunately, this usually means higher prices.
Many people find that it is necessary to buy a brand new mobile phone, computer or TV every year or every six months without thinking twice, but each purchase has the consequence of getting the elements that make them work.
Whether on the earth's surface or at the bottom of the sea, we must be wise in conserving resources, but we must also be wise in our choices. It's worth remembering that the next time the cursor moves to the buy button of your next "must-have" device, its creation has consequences. At the same time, we should carefully consider the strange contingencies brought about by past cooling to prevent the possibility of dire consequences from the current warming dilemma.
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