Category: Geology

Using whale songs to image beneath the ocean’s floor

Read the full story at Ars Technica.

Seismic data generated by whale songs helps build a picture of the ocean’s base.

What’s in oilfield wastewater matters for injection-induced earthquakes

Read the full story from Virginia Tech.

A team of geoscience researchers in the Virginia Tech College of Science has developed a new theory to explain how and why injection-induced earthquakes continue to occur even when injection rates decline.

How the seafloor of the Antarctic Ocean is changing – and the climate is following suit

Read the full story from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research.

Experts have reconstructed the depth of the Southern Ocean at key phases in the last 34 million years of the Antarctic’s climate history.

Associated journal article: K. Hochmuth, K. Gohl, G. Leitchenkov, I. Sauermilch, J. M. Whittaker, G. Uenzelmann‐Neben, B. Davy, L. De Santis (2020). “The Evolving Paleobathymetry of the Circum‐Antarctic Southern Ocean Since 34 Ma: A Key to Understanding Past Cryosphere‐Ocean Developments.” Geochemistry, Geophysics, Geosystems 21 (8) DOI: 10.1029/2020GC009122

An effective climate change solution may lie in rocks beneath our feet

Weathering of rocks like these basalt formations in Idaho triggers chemical processes that remove carbon dioxide from the air. Matthew Dillon/Flickr, CC BY

By Benjamin Z. Houlton, University of California, Davis

Why has Earth’s climate remained so stable over geological time? The answer just might rock you.

Rocks, particularly the types created by volcanic activity, play a critical role in keeping Earth’s long-term climate stable and cycling carbon dioxide between land, oceans and the atmosphere.

Scientists have known for decades that rock weathering – the chemical breakdown of minerals in mountains and soils – removes carbon dioxide from the atmosphere and transforms it into stable minerals on the planet’s surface and in ocean sediments. But because this process operates over millions of years, it is too weak to offset modern global warming from human activities.

Acid rain damage to buildings and monuments, like this sandstone statue in Dresden, Germany, is a form of chemical weathering. Slick/Wikipedia

Now, however, emerging science – including at the California Collaborative for Climate Change Solutions’ (C4) Working Lands Innovation Center – shows that it is possible to accelerate rock weathering rates. Enhanced rock weathering could both slow global warming and improve soil health, making it possible to grow crops more efficiently and bolster food security.

Rock chemistry

Many processes weather rocks on Earth’s surface, influenced by chemistry, biology, climate and plate tectonics. The dominant form of chemical weathering occurs when carbon dioxide combines with water in the soil and the ocean to make carbonic acid.

About 95% of Earth’s crust and mantle – the thick layer between the planet’s crust and its core – is made of silicate minerals, which are compounds of silicon and oxygen. Silicates are the main ingredient in most igneous rocks, which form when volcanic material cools and hardens. Such rocks make up about 15% of Earth’s land surface.

When carbonic acid comes in contact with certain silicate minerals, it triggers a chemical process known as the Urey reaction. This reaction pulls gaseous carbon dioxide from the atmosphere and combines it with water and calcium or magnesium silicates, producing two bicarbonate ions. Once the carbon dioxide is trapped in these soil carbonates, or ultimately washed into the ocean, it no longer warms the climate.

When carbonic acid dissolves calcium and magnesium silicate minerals, they break down into dissolved compounds, some of which contain carbon. These materials can flow to the ocean, where marine organisms use them to build shells. Later the shells are buried in ocean sediments. Volcanic activity releases some carbon back to the atmosphere, but much of it stays buried in rock for millions of years. Gretashum/Wikipedia, CC BY-SA

The Urey reaction runs at a higher rate when silicate-rich mountains such as the Himalayas expose fresh material to the atmosphere – for example, after a landslide – or when the climate becomes hotter and moister. Recent research demonstrates that humans can speed up the process substantially to help fight modern global warming.

Accelerated weathering

The biggest limit on weathering is the amount of silicate minerals exposed at any given time. Grinding up volcanic silicate rocks into a fine powder increases the surface area available for reactions. Further, adding this rock dust to the soil exposes it to plant roots and soil microbes. Both roots and microbes produce carbon dioxide as they decompose organic matter in the soil. In turn, this increases carbonic acid concentrations that accelerate weathering.

One recent study by British and Americans scientists suggests that adding finely crushed silicate rock, such as basalt, to all cropland soil in China, India, the U.S. and Brazil could trigger weathering that would remove more than 2 billion tons of carbon dioxide from the atmosphere each year. For comparison, the U.S. emitted about 5.3 billion tons of carbon dioxide in 2018.

Farming with rocks

One compelling aspect of enhanced weathering is that, in controlled-environment studies involving basalt amendments of soil, cereal grain yields are improved by roughly 20%.

As basalt weathers, it increases vital plant nutrients that can boost production and increase crops yields. Mineral nutrients such as calcium, potassium and magnesium create healthier soils. Farmers have been amending soil with rock minerals for centuries, so the concept is nothing new.

Spreading lime on a field in Devon, England to improve soil quality. Mark Robinson/Wikipedia, CC BY

At the Working Lands Innovation Center, we are conducting perhaps the largest enhanced weathering demonstration experiment on real farms in the world. We are partnering with farmers, ranchers, government, the mining industry and Native American tribes in California on some 50 acres of cropland soil amendment trials. We are testing the effects of rock dust and compost amendments on greenhouse gas emissions from the soil, carbon capture, crop yields, and plant and microbial health.

Our initial results suggest that adding basalt and wollastonite, a calcium silicate mineral, increased corn yields by 12% in the first year. Working with California’s greenhouse gas emissions trading program and our state’s diverse agricultural interests, we hope to establish a pathway that would offer monetary incentives to farmers and ranchers who allow enhanced rock weathering on their lands. We aim to create a protocol for farmers and ranchers to make money from the carbon they farm into the soil and help businesses and industry achieve their carbon neutrality goals.

Why negative emissions matter

Under the 2015 Paris climate agreement, nations have pledged to limit global warming to less then 2 degrees Celsius above preindustrial levels. This will require massive cuts in greenhouse gas emissions.

Pulling carbon dioxide from the air – also known as negative emissions – is also necessary to avoid the worst climate change outcomes, because atmospheric carbon dioxide has an average lifespan of more than 100 years. Every molecule of carbon dioxide that is released to the atmosphere through fossil fuel combustion or land clearing will remain there for many decades trapping heat and warming Earth’s surface. https://www.youtube.com/embed/4IUQn9uL6W0?wmode=transparent&start=0 In an even faster version of enhanced weathering, scientists pump supercritical carbon dioxide underground into basalt formations, where it reacts with minerals to form new solid rock.

Nations need a portfolio of solutions to create negative emissions. Enhanced weathering is poised for rapid scale-up, taking advantage of farm equipment that’s already in place, global mining operations and supply chains that currently deliver fertilizers and seeds worldwide. By addressing soil erosion and food security along with climate change, I believe rock weathering can help humans escape the hard place we find ourselves in today.

Benjamin Z. Houlton, Professor of Global Environmental Studies, Chancellor’s Fellow and Director, John Muir Institute of the Environment, University of California, Davis

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The Conversation

Online tool allows fast, free natural-hazard visualization

Read the full story from the University of Alaska Fairbanks.

Volcanoes can pulse and inflate before they erupt. Earthquakes can tear the ground along fault lines like a losing raffle ticket. Satellites can see these landscape events from space, and, now, a new tool will help scientists to better visualize them.

This spring, a team of scientists at the University of Alaska Fairbanks and the Alaska Satellite Facility released SARVIEWS 2.0, a free online service to monitor data from earthquakes and volcanoes.

The Geology Project: Bilingual Geoscience Communication by Bilingual Geoscientists

Read the full post at the Plainspoken Scientist.

During the AGU Fall Meeting 2019, I presented a talk on The Geology Project (TGP). TGP is a social media-based geoscience communication enterprise with special focus on providing content in both Spanish and English. Based in Puerto Rico, TGP is run by five young Puerto Rican geoscientists, with one mission: communicating science to the world! We are primarily Facebook-based, and our original written and audiovisual content is specifically geared towards the Spanish-speaking, and Puerto Rican public. We have social media followers in every Latin American country, and numerous other countries as well!

Lead pollution from Native Americans attributed to crushing galena for glitter paint

Read the full story at Phys.org.

Native American use of galena at Kincaid Mounds, a settlement occupied during the Mississippian period (1150 to 1450 CE), resulted in more than 1.5 metric tons of lead pollution deposited in a small lake near the Ohio River. New data from IUPUI researchers found the lead did not originate from this Southern Illinois settlement, but instead was brought to the site from other Midwest sources.

‘Ultimate gift to future generations’: plan to laser map all land on Earth

Read the full story in The Guardian.

A project to produce detailed maps of all the land on Earth through laser scanning has been revealed by researchers who say action is needed now to preserve a record of the world’s cultural, environmental and geological treasures.

Prof Chris Fisher, an archaeologist from Colorado State University, said he founded the Earth Archive as a response to the climate crisis.

Flights to image 3D geology in Illinois, Kentucky and Indiana

Read the full story from the Illinois State Geological Survey.

Scientists with the Illinois State Geological Survey are partnering with the U.S. Geological Survey and the Geological Surveys of Kentucky and Indiana to image geology using airborne geophysical technology as part of the USGS Earth Mapping Resource Initiative (Earth MRI).

Research project aims to build geospatial artificial intelligence for landform detection

Read the full story from Arizona State University.

Earth is enormous, and while humans have done a decent job of being able to map out the boundaries of countries and states, the roads in our cities and the location of geological sightseeing destinations, there remains a lot of the world that isn’t precisely figured out. But a new project from Wenwen Li, associate professor in the School of Geographical Sciences and Urban Planning, aims to learn more about our world and its varying terrain by applying artificial intelligence.

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