Ethnographic Arms & Armour - View Single Post

La Pagaru · 24th February 2019, 09:02 AM

WORLD RARE IRON MINERALS, THE GREEN RUST SOURCE (GREEN RUST) WHERE ARE IN MATANO AND AROUND IT, ONE OF THE INFLUENCE OF THE EARTH OF HISTORY OF IRON AND EARTH ATMOSFER.

Although it may appear sturdy, ancient sedimentary rocks called iron formations - the main source of world iron ore - were once dissolved in seawater. How does the iron go from being dissolved to the banded iron formation? Dr. Itay Halevy and his group in the Planet Weizmann Department of Earth and Science showed that billions of years ago, "rust" that formed in seawater and sank to a green ocean floor - iron-based minerals that are rare on Earth today but may have been relatively common .

We know that there is dissolved iron in the early oceans, and this is a strong indication that Earth's free oxygen concentration (O2) is very low. Otherwise, iron will react with oxygen to form iron oxide, which is a rusty red deposit that is familiar to anyone who leaves a bicycle in the rain. Today, said Halevy, iron is sent from the land to the ocean as small insoluble oxide particles in the river. But this sedimentation model only appears as an accumulation of free oxygen in the Earth's atmosphere, around 2, 5 billion years ago. With almost no oxygen, the oceans are rich in iron, but that does not mean that iron remains dissolved in unlimited seawater: Eventually it forms insoluble compounds with other elements and settles to the seabed to give rise to iron formations.

The idea that one of these insoluble compounds could be a rusty green mineral, Halevy said, occurred to him during his doctoral research, when he tried to recreate conditions on early Mars, including red rusty iron sediments. "I got some green things that I didn't recognize at first, which quickly turned orange when I exposed them to the air. With a little more experimentation, I found that this is a mineral called green rust, which is very rare on Earth today. , because of its affinity for oxygen. "Today green rust quickly turns into familiar red rust, but with not much oxygen free around, Halevy reasons, it can be an important way to dissolve iron to form solid compounds and settle into the seabed.

Support for these ideas comes from Sulawesi, Indonesia, where the current form of green rust on Lake Matano which is rich in iron and rich in oxygen, is considered similar to sea water that existed during a long period of Earth's history. To test his ideas in detail and explore their significance, Halevy arranged an experiment in which he and his team recreated, as close as possible, prehistoric, oxygen-free sea-water conditions. They found that green rust not only formed under these conditions, but when allowed to age, it turned into minerals found in Precambria iron formations - combinations of oxides containing iron, carbonate and silicate.

Can green rust be the main vehicle for precipitating iron from seawater? Halevy and his team developed a model to describe the iron cycle in the early oceans of Earth, including the possibility of the formation of green rust and competition by transporting other minerals from iron to the seabed. Their findings suggest that green rust may be a major player in the iron cycle. Iron in green rust then turns into minerals that we can now observe in geological records. "Of course, that would be one of several methods of iron buildup, just as a number of different processes are involved in chemical sedimentation in the oceans today," said Halevy. "But as far as we know, green rust should send most of the iron to the early marine sediments."

DR .ITA HALEVY
(WEIZZMAN INSTITUTE OF WORLD AND PLANET SCIENCE)

24th February 2019, 09:02 AM	#7
La Pagaru Member Join Date: Jan 2017 Location: Indonesia Posts: 84	luwu iron WORLD RARE IRON MINERALS, THE GREEN RUST SOURCE (GREEN RUST) WHERE ARE IN MATANO AND AROUND IT, ONE OF THE INFLUENCE OF THE EARTH OF HISTORY OF IRON AND EARTH ATMOSFER. Although it may appear sturdy, ancient sedimentary rocks called iron formations - the main source of world iron ore - were once dissolved in seawater. How does the iron go from being dissolved to the banded iron formation? Dr. Itay Halevy and his group in the Planet Weizmann Department of Earth and Science showed that billions of years ago, "rust" that formed in seawater and sank to a green ocean floor - iron-based minerals that are rare on Earth today but may have been relatively common . We know that there is dissolved iron in the early oceans, and this is a strong indication that Earth's free oxygen concentration (O2) is very low. Otherwise, iron will react with oxygen to form iron oxide, which is a rusty red deposit that is familiar to anyone who leaves a bicycle in the rain. Today, said Halevy, iron is sent from the land to the ocean as small insoluble oxide particles in the river. But this sedimentation model only appears as an accumulation of free oxygen in the Earth's atmosphere, around 2, 5 billion years ago. With almost no oxygen, the oceans are rich in iron, but that does not mean that iron remains dissolved in unlimited seawater: Eventually it forms insoluble compounds with other elements and settles to the seabed to give rise to iron formations. The idea that one of these insoluble compounds could be a rusty green mineral, Halevy said, occurred to him during his doctoral research, when he tried to recreate conditions on early Mars, including red rusty iron sediments. "I got some green things that I didn't recognize at first, which quickly turned orange when I exposed them to the air. With a little more experimentation, I found that this is a mineral called green rust, which is very rare on Earth today. , because of its affinity for oxygen. "Today green rust quickly turns into familiar red rust, but with not much oxygen free around, Halevy reasons, it can be an important way to dissolve iron to form solid compounds and settle into the seabed. Support for these ideas comes from Sulawesi, Indonesia, where the current form of green rust on Lake Matano which is rich in iron and rich in oxygen, is considered similar to sea water that existed during a long period of Earth's history. To test his ideas in detail and explore their significance, Halevy arranged an experiment in which he and his team recreated, as close as possible, prehistoric, oxygen-free sea-water conditions. They found that green rust not only formed under these conditions, but when allowed to age, it turned into minerals found in Precambria iron formations - combinations of oxides containing iron, carbonate and silicate. Can green rust be the main vehicle for precipitating iron from seawater? Halevy and his team developed a model to describe the iron cycle in the early oceans of Earth, including the possibility of the formation of green rust and competition by transporting other minerals from iron to the seabed. Their findings suggest that green rust may be a major player in the iron cycle. Iron in green rust then turns into minerals that we can now observe in geological records. "Of course, that would be one of several methods of iron buildup, just as a number of different processes are involved in chemical sedimentation in the oceans today," said Halevy. "But as far as we know, green rust should send most of the iron to the early marine sediments." DR .ITA HALEVY (WEIZZMAN INSTITUTE OF WORLD AND PLANET SCIENCE)