Lithosphere – Biofera http://biofera.org/ Sat, 15 Jan 2022 07:30:40 +0000 en-US hourly 1 https://wordpress.org/?v=5.8 https://biofera.org/wp-content/uploads/2021/05/biofera-icon-150x150.png Lithosphere – Biofera http://biofera.org/ 32 32 Volatile-consuming reactions fracture rocks and self-accelerate fluid flow in the lithosphere https://biofera.org/volatile-consuming-reactions-fracture-rocks-and-self-accelerate-fluid-flow-in-the-lithosphere/ Fri, 14 Jan 2022 19:55:27 +0000 https://biofera.org/volatile-consuming-reactions-fracture-rocks-and-self-accelerate-fluid-flow-in-the-lithosphere/

Importance

Hydration and carbonation are the primary reactions that drive Earth’s volatile cycles. These reactions are characterized by a large increase in solid volume, up to several tens of percent, and can induce fracturing, fluid flow and other reactions. However, no experimental study has succeeded in a net increase in fluid flow during reactions, and the mechanisms that control acceleration or deceleration remain largely unknown. Here we present clear experimental evidence that hydration reactions can fracture rocks and accelerate fluid flow, under confining pressure (i.e. at a simulated depth). We conclude that a high reaction rate, relative to fluid flow, is essential for fracturing and accelerating fluid flow during these reactions in the Earth.

Summary

The hydration and carbonation reactions within the Earth cause an increase in the solid volume of up to several tens of % by volume, which can induce stresses and fracture of the rock. Observations of naturally hydrated and carbonated peridotite suggest that permeability and fluid flow are enhanced by reaction-induced fracturing. However, permeability enhancement during solid-volume-increasing reactions has not been achieved in the laboratory, and the mechanisms of reaction-accelerated fluid flow remain largely unknown. Here, we present experimental evidence for significant enhancement of permeability by volume-increasing reactions under confining pressure. The hydromechanical behavior of sintered periclase hydration [MgO + H2O → Mg(OH)2] depends mainly on the initial pore-fluid connectivity. Permeability increased by three orders of magnitude for samples with low connectivity, while it decreased by two orders of magnitude for samples with high connectivity. Permeability enhancement was caused by hierarchical fracturing of reactive materials, while decrease was associated with homogeneous pore clogging by reaction products. These behaviors suggest that fluid flow, relative to reaction rate, is the primary control of hydromechanical evolution during bulking reactions. We suggest that extremely high reaction rate and low pore-fluid connectivity lead to local stress perturbations and are essential for reaction-induced fracturing and accelerated fluid flow during hydration/carbonation.

Footnotes

    • Accepted November 16, 2021.
  • Author contributions: research designed by MU; MU, KK and HK conducted research; MU and AO provided new analytical reagents/tools; MU analyzed the data; MU, AO and NT discussed the experimental results and their implications; and MU, AO and NT wrote the article.

  • The authors declare no competing interests.

  • This article is a direct PNAS submission.

  • This article contains additional information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2110776118/-/DCSupplemental.

Data availability

All study data is included in the article and/or IS Annex.

]]> A geoscience expert to study why continents split where magma is lacking https://biofera.org/a-geoscience-expert-to-study-why-continents-split-where-magma-is-lacking/ Wed, 05 Jan 2022 14:26:50 +0000 https://biofera.org/a-geoscience-expert-to-study-why-continents-split-where-magma-is-lacking/

D. Sarah Stamps. Credit: Mike Lee

The Earth’s surface keeps moving and changing shape, disintegrating and forming new land masses and oceans. In the billions of years of planet Earth’s history, there have been 10 supercontinents, the most famous and recent being Pangea which shattered around 175 million years ago.

Africa itself is slowly separating into several large and small tectonic blocks along the divergent East African Rift System, which includes Madagascar – the long island just off the coast of Southeast Africa – which itself will also divide into smaller islands. The culprit is the region’s rich and deep magma intrusions. Yet Africa is also experiencing continental rifts, separations, in areas where there is no evidence of magma intrusions. These types of continental rifts are known as low magma or “dry” rifts. In short, if it was a mystery, the identity of the culprit is unknown.

D. Sarah Stamps, associate professor in the Department of Geosciences, part of the Virginia Tech College of Science, wants to put her expertise in continental rifting to find the bad guy. Stamps recently received a $ 3 million grant from the National Science Foundation for the DRIAR project (short for Dry Rifting In the Albertine-Rhino Graben, Uganda) to help boost its efforts.

“You can think of the breakup of East Africa as the continuation of the breakup of Pangea,” said Stamps, head of the Geodesy and Tectonophysics Laboratory. “East Africa is actively disintegrating, and if this continues we will see new oceans forming. In northern parts of East Africa, such as Ethiopia and the Afar region, it has already spread to the point of forming baby ocean areas. the spread has already created a new oceanic crust. The land is sagging and the first stages of forming a new ocean basin are underway. “

Further south, in the East African Central Rift system, the continent’s break-up is less intense. This is where Stamps has spent much of his research career. For this effort, Stamps is leading a large team of experts. From the United States, his collaborators come from the Woods Hole Oceanographic Institute, the University of Kansas, Northwestern University, the University of California, Davis and Midwestern State University in Texas. In Uganda, the team works directly with the government’s Ministry of Energy and Mining Development and with Makerere University in Uganda.

“This team and I are very interested in understanding the physics of how a continent can shatter when there is no surface expression of magma in the form of volcanoes,” Stamps said.

The team will focus on the northwest branch of the East African Rift System located in Uganda, East Africa, where magma-poor rifting takes place. A wide range of geophysical, geological and geochemical observations will be collected and digital modeling of the region will be performed to understand how magma-poor rifts form and evolve.

Among the answers Stamps and coworkers seek to answer: In magma-rich faults, is deformation adapted by lithospheric weakening of melt? ; In poor magma rifts, is melt present below the surface weakening the lithosphere such that deformation is adapted during extension of the upper crust? ; And in magma-poor rifts, what if there is no deep melting and the deformation is lodged along fluid-filled faults or pre-existing structures such as lithospheric heterogeneities of inherited composition, structure and rheology?

“I hope there will definitely be impacts on our understanding of the physics of continental rifting,” Stamps said. “But we also have a lot of broader impacts in terms of capacity building in Uganda. So we will be organizing field schools in Uganda to teach people how to use the equipment and analyze the data.”

Three scientists, a Ph.D. work with Stamps. geoscience student from Uganda, Asenath Kwagalakwe, and two undergraduates from the Computer Modeling and Data Analysis program of the Academy of Data Sciences, third year student Esha Islam and Crystal Lee , third year student. The Academy of Data Science is also part of the College of Science.

“I’m working on the Albertine-Rhino Graben, which is the northernmost rift in the western branch of the East African rift system. My research interests focus on studying the physics of stress accommodation in the magma-poor eastern Albertine-Rhino Graben. African Rift System using geodynamic modeling and GNSS [Global Navigation Satellite System] geodesy, ”Kwagalakwe said.

Islam, on the other hand, took an elective geoscience course and greatly appreciated the presence of Stamps as a teacher in the classroom. Islam asked Stamps about research opportunities. “Data science is very flexible in what it can be applied to, and coding is used in most areas related to STEM. Therefore, even though I had no notable experience in geoscience, Dr Stamps was willing to offer me a place, ”she said. noted.

“Currently my job is to rerun test models from other graduate students to determine that we are all getting the same results. “

Lee added, “I was associated with the project through my friend, Esha Islam, who has worked with Dr Stamps for some time and is also a peer in my major. I was interested in joining the project when she told me about it because I wanted to expand my experience with data processing and modeling. ”Lee will analyze GNSS data collected in Uganda.

Among the benefits of the study, in addition to gaining a better understanding of the continental rift, Stamps highlights the improved estimates of carbon dioxide transfer to the atmosphere that occurs during the continental rift, advancing the rift models used to explore natural resources and create new information about the seismic risks associated with active fault.


East African rift system slowly disintegrates, with Madagascar splitting into pieces


Provided by Virginia Tech


Quote: A geoscience expert to study why continents separate where magma is lacking (2022, January 5) retrieved January 5, 2022 from https://phys.org/news/2022-01-geoscience-expert-continents-magma .html

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Indian army sets up quantum artificial intelligence lab https://biofera.org/indian-army-sets-up-quantum-artificial-intelligence-lab/ Wed, 29 Dec 2021 16:12:41 +0000 https://biofera.org/indian-army-sets-up-quantum-artificial-intelligence-lab/

The Indian Army, with assistance from the Secretariat of the National Security Council (NSCS), has established a Quantum and Artificial Intelligence Lab at the Military College of Telecommunications Engineering in Mhow, Madhya Pradesh to lead research and training in this key developing area.

The key areas are quantum key distribution, quantum communication, quantum computing and post-quantum cryptography, the force said.

The head of the Indian army, General MM Naravane, visited the facility to take stock of the situation and see the technological research carried out by the laboratories.

The Indian military has set up an artificial intelligence (AI) center in the same institution with more than 140 deployments in advanced areas and active support from industry and academia.

Cyber ​​warfare training is delivered through a state-of-the-art cyber range and cybersecurity labs. The ideation of the military’s involvement in electromagnetic spectrum operations was realized at a seminar on the electromagnetic spectrum and national security held in October last year.

Since then, an impetus has been given to the technological institutions of the Indian military to invest in AI, quantum and cyber.

Research undertaken by the Indian military in the field of quantum technology will make it possible to leap into next-generation communication and transform the current system of cryptography in the Indian armed forces into post-quantum cryptography (PQC).


Read also : Indian President conferred the rank of General

By adopting a multi-stakeholder approach incorporating universities (such as IITs), DRDO organizations, research institutes, companies, startups and industry players, this initiative is a good example of civil-military merger with Atmanirbhar Bharat a key factor.

Timeline-based targets with adequate funding have been developed for the projects and the gradual implementation of the solutions in the Indian military is expected on a rapid basis.

(IANS / RP)

(keywords: Indian army, Quantum, Artificial Intelligence Laboratory)

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Why air pollution is the greatest danger to public health in the world https://biofera.org/why-air-pollution-is-the-greatest-danger-to-public-health-in-the-world/ Wed, 29 Dec 2021 08:00:00 +0000 https://biofera.org/why-air-pollution-is-the-greatest-danger-to-public-health-in-the-world/

One of the greatest plagues of our time is air pollution, due not only to its impact on climate change but also on public and individual health due to increasing morbidity and mortality rates. . Many pollutants have become major contributors to disease in humans. Among them are particles (PM), particles of varying diameter but very small that enter the respiratory system by inhalation, causing respiratory and cardiovascular diseases, reproductive and central nervous system dysfunctions, and cancer.

Although ozone in the stratosphere plays a protective role against ultraviolet irradiation, PM is harmful when present in high concentrations at ground level. In addition, nitrogen oxides, sulfur dioxide, volatile organic compounds (VOCs), dioxins and polycyclic aromatic hydrocarbons (PAHs) are all considered to be air pollutants harmful to humans.

Carbon monoxide can even cause direct poisoning when consumed at high levels. Heavy metals such as lead, when absorbed into the human body, can lead to direct poisoning or chronic poisoning, depending on exposure. The diseases caused by the above mentioned substances mainly include respiratory problems such as chronic obstructive pulmonary disease (COPD), asthma, bronchiolitis, lung cancer, cardiovascular events, central nervous system dysfunctions and skin diseases.

Air pollution not only has an impact on climate change, but also on public and individual health due to increasing morbidity and mortality rates.

Last but not least, climate change resulting from environmental pollution affects the geographic distribution of many infectious diseases, as do natural disasters. The only way to tackle this problem is public awareness coupled with a multidisciplinary approach by scientific experts; national and international organizations must face up to the urgency of this threat and propose lasting solutions.

Approach to the problem

The interactions between humans and their physical environment have been widely studied, as multiple human activities influence the environment. The environment is a coupling of the biotic (living organisms and microorganisms) and the abiotic (hydrosphere, lithosphere and atmosphere).

Pollution is defined as the introduction of substances harmful to humans and other living organisms into the environment. Pollutants are noxious solids, liquids or gases produced in higher concentrations than usual that reduce the quality of our environment.

Human activities take a toll on the environment by polluting the water we drink, the air we breathe and the soil in which plants grow. While the industrial revolution was a great success in terms of technology, society and multiple service delivery, it also introduced the production of huge amounts of pollutants emitted into the air which are harmful to human health.

Girl wearing a mask to protect herself from Covid-19
Air pollution account for about nine million deaths per year. | Image credit: Sanchit Khanna / Hindustan Times via Getty Images

Without a doubt, global environmental pollution is seen as a multifaceted international public health problem. Social, economic and legislative concerns and lifestyle are linked to this major problem. It is clear that urbanization and industrialization are reaching unprecedented and overwhelming proportions in the world in our time. Human-caused air pollution is one of the greatest risks to public health in the world, given that it account for about nine million deaths per year.

Sources of air pollution

It is known that the majority of environmental pollutants are emitted by large-scale human activities such as the use of industrial machines, power plants, combustion engines and cars. Because these activities are carried out on such a large scale, they are by far the biggest contributors to air pollution, with cars responsible for around 80% of pollution today.

Other human activities also influence our environment to a lesser extent. These activities include field cultivation techniques, gas stations, fuel tank heaters, and clean-up procedures, as well as several natural sources, such as volcanic eruptions, soil eruptions, and forest fires. The classification of air pollutants is based primarily on the sources of pollution. Therefore, it is worth mentioning the four main sources, according to the classification system: main sources, area sources, mobile sources and natural sources.

The main sources include emissions of pollutants from power plants, refineries and petrochemicals, chemical and fertilizer industries, metallurgical and other industrial plants and, finally, municipal incineration.

Indoor sources include household cleaning operations, dry cleaners, printing houses and gas stations.

environmental pollution

Mobile sources include automobiles, cars, railways, airways, and other types of vehicles.

Finally, natural sources include, as noted earlier, physical disasters such as forest fires, volcanic erosion, dust storms, and farm fires.

However, many classification systems have been proposed. Another type of classification is a grouping according to the recipient of the pollution, as follows:

Air pollution is determined as the presence of pollutants in the air in large quantities for long periods of time. Air pollutants are dispersed particles, hydrocarbons, CO, CO2, NO, NO2, SO3, etc.

Air pollutants

The World Health Organization (WHO) reports six major air pollutants, namely particulate matter pollution, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides and lead. Air pollution can have a disastrous effect on all components of the environment, including groundwater, soil and air. In addition, it poses a serious threat to living organisms.

In this vein, our interest is mainly to focus on these pollutants, as they are linked to wider and more serious problems in terms of impact on human health and the environment. Acid rain, global warming, the greenhouse effect and climate change have a significant ecological impact on air pollution.

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Iisc: the volcanoes of the last mass extinction created the Himalayas | Bangalore News https://biofera.org/iisc-the-volcanoes-of-the-last-mass-extinction-created-the-himalayas-bangalore-news/ Sun, 26 Dec 2021 22:11:00 +0000 https://biofera.org/iisc-the-volcanoes-of-the-last-mass-extinction-created-the-himalayas-bangalore-news/ BENGALURU: Researchers at the Indian Institute of Science (IISc) have built models to determine whether volcanism – a magma eruption on the planet’s surface – that caused the last mass extinction 65 million years ago caused erosion of the Indian continental lithosphere. Following the movement of the Indian Plate, they also suggested that such erosion could have created the Himalayan mountain range.
Some hypotheses suggest that a supervolcano (a mantle plume) erupted at around 65 Ma – each Ma or mega-year is one million years – which significantly affected Earth’s climate, resulting in the fifth event d Mass extinction called KT boundary mass extinction which saw reptiles such as dinosaurs being wiped out. “This volcanism occurred just under the then Indian Plate, in a place known as Reunion, now in the southern Indian Ocean. Scientists have suggested that volcanism likely created the Indian Deccan Plateau and affected the dynamics of the Indian Plate in several ways, ”IISc said.
In their new study, Jyotirmoy Paul and Attreyee Ghosh of the Earth Sciences Center (CES) of the IIAS, investigated the interaction between the Indian plate and the Reunion plume using digital models of mantle convection.
The researchers constructed “weather-dependent spherical forward mantle convection models” to determine whether the eruption of the “Réunion plume” could have reduced the thickness of the Indian craton. Their results show that due to the eruption of the Réunion plume, around 130 km of the Indian mainland lithosphere may have been eroded, making it an unusually thin plate compared to other continental plates.
“In addition, the plume material could have lubricated the border between the Indian plate and the underlying mantle. As a result, the Indian plate could slide over the mantle very quickly, reaching the highest speed ever recorded by all the plates (around 20 cm / year) since 65 Ma. Such a fast speed could be a potential reason for the impact. massive between the Indian and Eurasian Plates, ultimately forming the world’s tallest mountain range – the Himalayas, ”the researchers said. Source link

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Determining transmissibility of novel variants may help immunization programs and healthcare response – ScienceDaily https://biofera.org/determining-transmissibility-of-novel-variants-may-help-immunization-programs-and-healthcare-response-sciencedaily/ Fri, 24 Dec 2021 00:52:17 +0000 https://biofera.org/determining-transmissibility-of-novel-variants-may-help-immunization-programs-and-healthcare-response-sciencedaily/ As the discovery of the new omicron variant illustrates, new COVID-19 variants will continue to emerge on a regular basis. In an effort to make sense of these new variants, scientists at the Los Alamos National Laboratory have developed methods to quantify how more or less transmissible they are, which could have far-reaching implications for public health by terms of COVID-19 risk and vaccination levels required to achieve herd immunity.

“In general, newer variants of COVID-19 are simply discussed in terms of being more dangerous or spreading faster than previous strains,” said Ethan Romero-Severson, computer epidemiologist in the Theoretical Division of Los Alamos and main author of the article published in Nature Communication. “We have shown that it is possible to calculate the transmission benefit of new strains while taking into account alternative explanations such as migration and random genetic drift. Our collection of methods allows us to examine both the global situation in general and specific countries in more detail using publicly available genetic sequence data. “

Los Alamos’ research is “a method of integrating molecular epidemiological surveillance into surveillance systems using publicly available data streams,” Romero-Severson noted.

The team used two distinct but complementary approaches. The first is derived from classical methods of population genetics that relate the increased transmissibility of a variant of COVID-19 to the expected frequency of that variant in the population over time.

“We modified this model to include migration as a possible alternative explanation for increased transmissibility and implemented it in a hierarchical modeling framework that allowed us to estimate the unique selection effect for each variant. in every country in which it has appeared, ”he said.

The second, more detailed method used a stochastic epidemiological model (allowing for uncertainty) to predict both changes in the frequencies of COVID-19 variants and deaths over time, taking into account natural and random variations in the virus both between and within countries over time.

Together, these approaches have shown that the pattern of emerging and increasing variants of COVID-19 around the world is due to sharp increases in the transmissibility of the virus over time. The methods also clearly established that early detection of variants of concern is possible even when the overall frequency of new variants is as low as 5 percent.

Source of the story:

Materials provided by DOE / Los Alamos National Laboratory. Note: Content can be changed for style and length.

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Arc-bound lava zinc isotopes reveal the recycling of fore-arc serpentinites into the subarc mantle https://biofera.org/arc-bound-lava-zinc-isotopes-reveal-the-recycling-of-fore-arc-serpentinites-into-the-subarc-mantle/ Thu, 23 Dec 2021 17:56:37 +0000 https://biofera.org/arc-bound-lava-zinc-isotopes-reveal-the-recycling-of-fore-arc-serpentinites-into-the-subarc-mantle/

Credit: Unsplash / CC0 Public domain

Serpentinite, formed by low temperature hydrothermal alteration of mantle peridotite, is distributed in the lithospheric mantle at the bottom of the subduction slab (slab-serpentinite) and the corner of the fore-arc mantle above the subduction slab (mantle serpentinite) in the subduction zone.

Since they usually contain a large amount of water, mobile fluid elements (Cs, Rb, Sr, Ba, Pb, Li, etc.) and heavy B isotopes, using traditional geochemical means to distinguish the two different sources of serpentinite fluids in the genesis of arc magmas is difficult.

A research team led by Zeng Zhigang of the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS), in collaboration with Professor Chen Jiubin of Tianjin University, studied the isotopes of zinc in lavas linked to Western Pacific subduction and their implications for crust-mantle recycling.

Their study, published in Journal of Geophysical Research: Solid Earth, provided an effective way to distinguish the contributions of fluids derived from slab and mantle serpentinite to arc magmas, which is important for understanding the role of serpentinite in material recycling in areas of subduction.

The researchers found that the arc-related lavas had an inferior66values ​​of Zn than those of basalts of the mid-oceanic ridge (MORB), while the lavas of the back-arc presented values ​​of the MORB type δ66Zn values. What’s more,66Zn has a good correlation with the proxies for the addition of fluid (87Sr /86Sr and Ba / La) and the depths of the slabs.

Since mantle fusion and magmatic differentiation induce high enrichment of Zn isotopes in primary and evolved magmas, respectively, while melt extraction results in limited fractionation of Zn isotopes in the mantle, low lavas66Zn values ​​therefore potentially indicate the involvement of isotopically light fluids in their mantle sources.

Unlike the heavy Zn isotope of plate serpentinites, fore-arc serpentinites are typically characterized by an extremely light Zn isotope. As a result, the fluids released by the dehydration of the fore-arc serpentinite have a significantly lower Zn isotopic composition relative to the mantle corner.

Therefore, these pre-arc materials were likely dragged down to subarctic depths and released isotopically light Zn in the fluids to modify the wedge of the overlying mantle, thus producing a weak δ66Zn values ​​in arc-related magmas. Beyond the depths of the sub-arc, the serpentinites of the fore-arc were completely decomposed, so that the light isotopic fluids of Zn were absent.

Consequently, the lavas of the back-arc basin presented a MORB type66Zn values. He provided conclusive evidence for the hypothesis that serpentinites from the mantle corner of the fore-arc could be involved in the subduction channel and transported to the depth of the sub-arc, then dehydrate and modify the mantle corner. of the sub-arc.


Recycling of tectonic plates a key factor in Earth’s oxygen budget


More information:
Zuxing Chen et al, the zinc isotopes of the arc-bound Mariana and Ryukyu lavas reveal the recycling of fore-arc serpentinites in the subarc mantle, Journal of Geophysical Research: Solid Earth (2021). DOI: 10.1029 / 2021JB022261

Provided by Chinese Academy of Sciences


Quote: Zinc isotopes from arc-related lavas reveal the recycling of fore-arc serpentinites in the sub-arc mantle (2021, December 23) retrieved December 26, 2021 from https://phys.org/ news / 2021-12-zinc-isotopes-arc-related-lavas -reveal.html

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When two plates slide on top of each other https://biofera.org/when-two-plates-slide-on-top-of-each-other/ Sun, 19 Dec 2021 08:00:00 +0000 https://biofera.org/when-two-plates-slide-on-top-of-each-other/
Through Robert Hazen, Ph.D., George Mason University

Tectonic plates are large chunks of the lithosphere – about 50 or 100 kilometers thick, but thousands of kilometers in diameter – and lithospheric plates are displaced when they straddle the asthenosphere, which is mobile and moving. Transformation boundaries are a kind of plate boundary. They are basically faults where two plates slide over each other.

An image of the San Andreas Fault in Hanford, USA
The San Andreas Fault is the longest highly active transformational frontier on the Earth’s surface. (Image: oliverdelahayeShutterstock)

The Lithosphere and the Asthenosphere

The lithosphere and asthenosphere are the two major layers associated with plate tectonics.

The lithosphere consists of the crust and the upper part of the mantle; it is a relatively thin layer, about 50 to 100 kilometers thick. It is also relatively cold, less than 1000 degrees centigrade, and at these temperatures the rock is brittle. That is, if you take a hammer and hit it, it will break; it will shatter, like a brittle piece of ceramic. This solid rock layer is the lithosphere.

It covers a softer layer, the asthenosphere soft and warm. This layer of asthenosphere extends deep into the mantle. It’s hotter – temperatures are usually over 1000 degrees – and it’s hot enough to make the rock relatively soft and plastic; more like a taffy.

This is a transcript of the video series The joy of science. Watch it now, on Wondrium.

Transform the boundaries

Transformation limits are faults where two plates slide over each other. Such boundaries are inevitable whenever you have a sphere divided into diverging and converging boundaries. The most common is the San Andreas fault; it is the longest highly active transformation frontier on the Earth’s surface.

Major earthquakes occur along the San Andreas fault every few decades. Geologists predict that another severe earthquake is to occur in Southern California in the next quarter century or so; stress builds up too much.

There are also transformation limits along ocean ridge systems.

Transformation limit locations

If you look at a seabed map, you will see that the ridges are shifted from time to time; and these offsets are transformation limits of a shorter kind. They involve areas where the plaques meet; they move relative to each other, but they neither diverge nor converge.

Geologists have also identified several silent transformation boundaries, those that do not move. The plates meet, they are in contact; but at least for now, they don’t move much. There is such a passive border between the Eurasian plate and the African plate. At some point in the future these boundaries may move, there may be giant earthquakes along them; but at least for now they seem to be calm.

Learn more about the rock cycle.

Volcanic areas called hot spots

An image of the Hawaii hotspot.
There are around 100 hot spots around the world. (Image: Bourrichon / Public domain)

Large-scale mantle convection drives plate tectonics and controls most of Earth’s volcanoes. You have volcanoes at divergent borders, where a new crust is formed, and therefore you have a ridge of volcanoes. You have volcanoes along converging borders that are about 100 to 200 kilometers inland from the actual border.

But there are other well-known volcanic areas, including Hawaii and Yellowstone, which lie in the middle of the plates. What is happening with these volcanoes? These areas are called hot spots. They are found all over the world; there are about 100 of them in the world, and they represent another type of mantle convection, which is still quite poorly understood.

Appearance of a hot spot

Hot spots appear to appear when a narrow plume of magma rises from the depths of the mantle. Perhaps the core-mantle boundary is the source of these hot spots; it would be 3,000 kilometers lower. The location of the hot spots seems to be absolutely independent of the tectonic movements of the plates.

For example, if you look at the Hawaii mountain range, you see that the mountain range appears to have moved northwest. The reason is that the plate itself moves and the hot spot remains fixed. You have a fixed hot spot; As the plate gradually moves, the new volcanic islands that are forming appear more and more to the southeast, in this chain of islands.

Learn more about earthquakes and volcanoes.

The fixed hot spot

If you look at the volcanic islands, the present-day Big Island of Hawaii, where active volcanism occurs, is the largest; this is where all the action takes place. As you move further away from Hawaii, you see more and more eroded islands. If you study sonar even further, there is a huge string of volcanic islands underwater; that is, things that were once islands, but are now eroded below ocean level.

It stretches hundreds of kilometers to the northwest. This indicates that the hot spot has been fixed for a long time and the Pacific plate has moved on it.

There is still a lot to understand about hot spots, and their origin remains a hot topic of research.

Common questions about processing limits and hot spots

Q: What are processing limits?

Transform the boundaries are faults where two plates slide against each other. Such borders are inevitable due to divergent and converging borders. The most common transformation boundary is the San Andreas fault; it is the longest highly active transformation frontier on the Earth’s surface.

Q: What are the limits of silent transformation?

Silent transformation limits are borders that do not move. The plates are in contact at these limits but do not move much at this time. Geologists have found passive transformational boundaries between the Eurasian Plate and the African Plate.

Q: What are hot spots? How do they arise?

Hot spots are volcanic areas that lie right in the middle of the plates. They seem to arise when a narrow plume of magma rises from the depths of the mantle. The location of the hot spots seems to be absolutely independent of the tectonic movements of the plates.

Keep reading
Volcanic eruptions: dramatic and violent events on the Earth’s surface
The internal structure of the Earth and seismic waves
Understanding plate tectonics and its importance on Earth

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As we fight to recycle lithium-ion batteries, what future for electric vehicles in India? https://biofera.org/as-we-fight-to-recycle-lithium-ion-batteries-what-future-for-electric-vehicles-in-india/ Sat, 18 Dec 2021 15:23:23 +0000 https://biofera.org/as-we-fight-to-recycle-lithium-ion-batteries-what-future-for-electric-vehicles-in-india/

With countries still chasing Li-Ion batteries, they have been labeled obsolete.

They find uses in consumer goods like cell phones, laptops, other electronic devices and even in several industries as a critical input.

The best use that makes them the most desirable is their legacy use in electric vehicles or electric vehicles. Lithium-ion batteries bring dreams of electric mobility to life.

Indeed, lithium-ion batteries constitute the most important part of these green vehicles, covering almost 50% of their total cost.

Without adequate access to these batteries, sustainable mobility was seen as just a far-fetched idea.

Why are electric vehicles being promoted around the world?

The world and its conventions vouch for the use of electric vehicles because of their comparative advantages in preserving the environment.

The second reason for a country like India to seek this option remains the large ForEx (Foreign Exchange) imbalance we face when importing oil into the country for energy.

But some challenges in dealing with the very lithium that we saw as our savior have caused us to give up the same, in just a few decades.

On the one hand, India does not have a significant source of metals like cobalt or lithium, for use in electric vehicles.

On top of that, most lithium supplies (97%) are controlled by China, and its availability in the open market is disrupted by any gap in bilateral relations.

Their treatment and elimination after the end of their life because they are dangerous and sometimes explosive in nature.

Therefore, their safety should be ensured by proper recycling, in an environmentally friendly way without denigrating more lives, it means saving all the time.

Hence, there are alternatives such as lithium metal batteries or aluminum air batteries etc. entering the electric vehicle market.

In addition, as one expert explains: “EV packs are complex to disassemble into individual cells, so recyclers must unload the packs into conductive baths before mechanically shredding them into a mixture of constituent materials.”

“In addition, new batteries are currently less expensive to produce, which discourages recycling of batteries as the value of recovered materials is reduced. “

But it should be noted how some companies in India have patented this technology to proceed.

Why is recycling necessary?

30% of a single Li-ion cell is made up of the required metals including cobalt, graphite, lithium, nickel, manganese, copper, etc.

Li-ion battery

If attempted by the best of routes, cobalt (battery grade) with even 98% purity, or pharmaceutical grade lithium carbonate, etc. can be successfully mined.

In addition to finding uses in Li-Ion batteries, they can also be used as a component in psychotropic drugs.

Due to various limitations in acquiring these rarities, recycling seems to be the best imperative available.

For example, 70 percent of the world’s cobalt comes from the DR Congo region where it is achieved using child labor and terrorist regimes.

In addition to the above benefit, we are not burning or digging up the Earth’s lithosphere to get our hands on these bulky minerals.

Thus, to ensure a smooth energy transition, provide decent growth in electric mobility and make an Atmanirbhar Bharat, India will have to ensure the investments that are pouring into the sector.

Lithium-ion recycling and the world:

A new report from Wood Mackenzie has attempted to visualize the expected penetration of electric vehicles in the global market to reach 23% by 2030.

And thereafter, the demand for batteries is expected to reach 89% by 2040, compared to the current demand and this increase can be attributed more to the automotive sector.

The lead author of the report explains: “The demand market for Li-ion batteries can fluctuate over the months and expand upstream and midway to produce battery materials, implying delays of several years.”

“Because this is a new industry, the historical ability to turn on the switch is limited, yet many see it as an environment for recycling to have a tangible impact. “

Shedding new light on the green mobility sector during this decade, the report mentions:

The supply chain will become further established to be able to supply large quantities of chemicals and battery grade cathodes to cell manufacturers, while recyclers will grapple with the large mass and complexity of EV packs. “

Another limit to recycling batteries is their increasingly long lifespan, i.e. up to 15 years.

For this reason, the report states that there is a lack of secondary supply from recycling, which is evident.

And the total capacity of planned recycling facilities could see an available raw material increase in 2030 when end-of-life electric vehicles start to disappear from the markets.

Will China continue to dominate the electric vehicle market even in this decade?

China has strived to develop more integrated raw material supply chains than any other country and will therefore remain the most attractive place to invest in battery recycling.

India is right on the brink of another revolution and it will only give in if we use the very opportunity we have now, start restructuring our supply chains and safely break redundant batteries to ensure uptime. .

We have the technology to recycle Li-Ion batteries which can help us solve the problem of hazardous electronic waste and become a budding leader in the production of green batteries.

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A halogen balance of the earth’s bulk silicate indicates a history of early halogen degassing followed by net regassing https://biofera.org/a-halogen-balance-of-the-earths-bulk-silicate-indicates-a-history-of-early-halogen-degassing-followed-by-net-regassing/ Thu, 16 Dec 2021 19:58:37 +0000 https://biofera.org/a-halogen-balance-of-the-earths-bulk-silicate-indicates-a-history-of-early-halogen-degassing-followed-by-net-regassing/

Importance

Halogens play an essential role in biochemistry and are useful in understanding how planets formed and evolved. As we have found that the traditional way of limiting the halogen balance within the Earth is unreliable, we have developed a method that better utilizes relevant geochemical data and estimated halogen abundances in various silicate reservoirs. of the earth. Our halogen balance indicates that the majority of halogens are more concentrated in the mantle than on the surface and suggests that the halogens probably underwent early outgassing and subsequent net regassing. This study also provides an important key to deciphering the geological history of ocean chemistry.

Summary

Halogens are important tracers of various planetary formation and evolutionary processes, and a precise understanding of their abundance in Earth’s silicate reservoirs can help us piece together the history of mantle-atmosphere interactions. and the oceans. Previous studies of halogen abundances in Earth’s silicate mass (BSE) are based on the assumption of constant element abundance ratios, resulting in a gross underestimation of the halogen balance of BSE. Here we present a more robust approach using a linear log-log model. Using this method, we provide an internally consistent estimate of halogen abundances in the source mantle of depleted mid-ocean basalt (MORB), the source mantle of enriched ocean basalt (OIB), depleted mantle and BSE. Unlike previous studies, our results suggest that the halogens in BSE are not more depleted relative to elements with similar volatility, thus indicating sufficient retention of halogens during planetary accretion. Based on the abundances of halogens in the depleted mantle and BSE, we estimate that approximately 87% of all stable halogens reside in the current mantle. Given our understanding of the history of mantle outgassing and the evolution of crustal recycling, the revised halogen balance suggests that the deep halogen cycle is characterized by efficient early earth outgassing and net regasing. later in the rest of Earth’s history. Such an evolution of the deep halogen cycle represents a major step towards a more complete understanding of the ancient alkalinity of the oceans, which affects the distribution of carbon in the hydrosphere, the stability of crustal and authigenic minerals, and the development of early life. .

Footnotes

    • Accepted November 9, 2021.
  • Author contributions: research designed by JK; MG carried out research; MG and JK analyzed the data; MG wrote the paper; and JK discussed the results and commented on the manuscript.

  • The authors declare no competing interests.

  • This article is a direct PNAS submission.

  • This article contains additional information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2116083118/-/DCSupplemental.

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