Reading ancient climate from plankton shells

This is a CT reconstruction of a foram measured at the Diamond Light Source. -  Oscar Branson, University of Cambridge
This is a CT reconstruction of a foram measured at the Diamond Light Source. – Oscar Branson, University of Cambridge

Climate changes from millions of years ago are recorded at daily rate in ancient sea shells, new research shows.

A huge X-ray microscope has revealed growth bands in plankton shells that show how shell chemistry records the sea temperature.

The results could allow scientists to chart short timescale changes in ocean temperatures hundreds of millions of years ago.

Plankton shells show features like tree rings, recording historical climate.

It’s important to understand current climate change in the light of how climate has varied in the geological past. One way to do this, for the last few thousand years, is to analyse ice from the poles. The planet’s temperature and atmosphere are recorded by bubbles of ancient air trapped in polar ice cores. The oldest Antarctic ice core records date back to around 800,000 years ago.

Results just published in the journal Earth and Planetary Sciences Letters reveal how ancient climate change, pushing back hundreds of millions of years ago into deep time, is recorded by the shells of oceanic plankton.

As microbial plankton grow in ocean waters, their shells, made of the mineral calcite, trap trace amounts of chemical impurities, maybe only a few atoms in a million getting replaced by impurity atoms. Scientists have noticed that plankton growing in warmer waters contain more impurities, but it has not been clear how and why this “proxy” for temperature works.

When the plankton die, they fall to the muddy ocean floor, and can be recovered today from that muddy ocean floor sediments, which preserve the shells as they are buried. The amount of impurity, measured in fossil plankton shells, provides a record of past ocean temperature, dating back more than 100 million years ago.

Now, researchers from the Department of Earth Sciences at the University of Cambridge have measured traces of magnesium in the shells of plankton using an X-ray microscope in Berkeley, California, at the “Advanced Light Source” synchrotron – a huge particle accelerator that generates X-rays to study matter in minuscule detail.

The powerful X-ray microscope has revealed narrow nanoscale bands in the plankton shell where the amount of magnesium is very slightly higher, at length scales as small as one hundredth that of a human hair. They are growth bands, rather like tree rings, but in plankton the bands occur daily or so, rather than yearly.

“These growth bands in plankton show the day by day variations in magnesium in the shell at a 30 nanometre length scale. For slow-growing plankton it opens the way to seeing seasonal variations in ocean temperatures or plankton growth in samples dating back tens to hundreds of millions of years”, says Professor Simon Redfern, one of the experimenters on the project.

“Our X-ray data show that the trace magnesium sits inside the crystalline mineral structure of the plankton shell. That’s important because it validates previous assumptions about using magnesium contents as a measure of past ocean temperature.”

The chemical environment of the trace elements in the plankton shell, revealed in the new measurements, shows that the magnesium sits in calcite crystal replacing calcium, rather than in microbial membranes in their impurities in the shell. This helps explain why temperature affects the chemistry of plankton shells – warmer waters favour increased magnesium in calcite.

The group are now using the UK’s “Diamond” synchrotron X-ray facility to measure how plankton shells grow and whether they change at all in the ocean floor sediments. Their latest results could allow scientists to establish climate variability in Earth’s far distant past, as well as providing new routes to measure ocean acidification and salinity in past oceans.

What do we know — and not know — about fracking?

Fracking is in the headlines a lot these days, and everyone has an opinion about it. But how much do we really know for certain about the oil and gas extraction technique and its health effects? And how do we find out the truth among all the shouted opinions? To help cut through the static, several scientists have put together a multidisciplinary session on fracking and health at the meeting of The Geological Society of America (GSA) in Denver on Sunday.

“There is so much perceived information on fracking in the media, with so little of it based on real science and actual data,” says Thomas Darrah, a medical geologist at Ohio State University and one of the conveners of the GSA Pardee Keynote Session, “Energy and Health: The Emergence of Medical Geology in Response to the Shale Gas Boom.”

“Fracking has moved so quickly, and the research community is playing catch up on water, air, and health issues,” said Robert Jackson, an environmental scientist at Duke University who will present his research this Sunday. “The goal is to present a state of the science for researchers and the public.”

The afternoon keynote session is designed to cover a lot of ground. It will start with the geologists, hydrologists, and air-quality experts who are studying the chemistry and the physical properties of fracking in the ground, water, and air. Then the session veers into territory not often covered at a geological meeting, with talks by toxicologists, researchers in occupational medicine, and epidemiologists.

“This session includes people who would normally not be anywhere near a GSA conference,” said Darrah. “The idea is that we end the session by having the geoscience community interact with a group of people who are looking at health data sets: epidemiologists. That way we can put people working on the other end of the equation in the same room.” Included in the eleven scheduled presentations, and at the medical end of the equation, is a talk titled “Public Health Implications of Hydraulic Fracturing,” by David O. Carpenter of the University of Albany’s School of Public Health, and another, “Energy and Health: The Emergence of Medical Geology in Response to the Shale Gas Boom: An Occupational and Environmental Medicine Perspective,” to be delivered by Theodore F. Them of Guthrie Clinic Ltd.

For his part, Darrah will be presenting a talk about his work, “Understanding In-House Exposures to Natural Gas and Metal-Rich Aerosols from Groundwater within an Unconventional Energy Basin.”

There are two additional presentations on the air-quality issues of fracking, which is perhaps the topic the public knows the least about. Gabrielle Petron of the University of Colorado and NOAA will be talking about outdoor air emissions from hydraulic fracturing activities, and public health researcher Lisa M. Mackenzie of the University of Colorado will talk about work evaluating specific health risks from exposure to natural gas drilling in Garfield County, Colorado.

Radioactive waste: Where to put it?

As the U.S. makes new plans for disposing of spent nuclear fuel and other high-level radioactive waste deep underground, geologists are key to identifying safe burial sites and techniques. Scientists at The Geological Society of America (GSA) meeting in Denver will describe the potential of shale formations; challenges of deep borehole disposal; and their progress in building a computer model to help improve understanding of the geologic processes that are important for safe disposal of high-level waste.

In the United States, about 70,000 metric tons of spent commercial nuclear fuel are located at more than 70 sites in 35 states. Shales and other clay-rich (argillaceous) rocks have never been seriously considered for holding America’s spent nuclear fuel, but it is different overseas. France, Switzerland, and Belgium are planning to put waste in tunnels mined out of shale formations, and Canada, Japan, and the United Kingdom are evaluating the idea.

At the GSA meeting, U.S. Geological Survey hydrogeology expert C.E. Neuzil of Reston, Virginia, will report that some shales are so impermeable that there is little risk of radioactivity from buried nuclear waste reaching ground or surface water.

“This is usually difficult to demonstrate,” Neuzil says, “but some shales have natural groundwater pressure anomalies that can be analyzed — as if they were permeability tests — on a very large scale.” This capability was shown recently at the Bruce Nuclear Site, explains Neuzil, a proposed low/intermediate waste repository 1,200 feet underground in Ontario, Canada. Argillaceous rocks have additional attractive qualities, Neuzil says: They are common, voluminous, and tend to be tectonically quiet — meaning no earthquakes to crack the walls of a fuel-rod burial chamber.

Another disposal option for nuclear waste is deep boreholes. The 2012 presidential Blue Ribbon Commission on America’s Nuclear Future recommended more research, and the U.S. Department of Energy is now developing an R&D plan. However, the U.S. Nuclear Waste Technical Review Board (NWTRB) has statutory responsibility for evaluating the technical validity of DOE’s nuclear waste activities, and is on the record with the position that deep boreholes present many technical challenges and studying them “should not delay higher priority research on a mined geologic repository.”

At next week’s GSA meeting, Review Board senior staff professional Bret W. Leslie and Stanford University geophysicist Mary Lou Zoback, an NWTRB member, will present the board’s assessment of:

  • the technical feasibility of drilling a borehole of the proposed depth (3 miles) and width (about 20 inches), which has never been done;

  • the exposure risk for workers, who would have to repackage waste currently stored in canisters that are wider than the width of the proposed boreholes;
  • the reliability of existing sealing technology; and
  • the large number of deep boreholes that would be required — nearly 700.

Whether nuclear waste winds up in tunnels, boreholes or both, the planning will be helped by new analytical tools. One is a new computer model that will evaluate the behavior of various forms of nuclear waste, and waste containers and barriers, if stored in various rocks. The model is being developed under the auspices of the Center for Nuclear Waste Regulatory Analyses (CNWRA), the NRC’s federally funded research and development center, and will be described at the GSA meeting by NRC performance analyst Jin-Ping Gwo.

Could the Colorado River once have flowed into the Labrador Sea?

A figure stands on Esplanade surface opposite Vulcan's Throne volcano, Grand Canyon, USA. Photo by J.W. Sears. -  Photo by James W. Sears
A figure stands on Esplanade surface opposite Vulcan’s Throne volcano, Grand Canyon, USA. Photo by J.W. Sears. – Photo by James W. Sears

In the November issue of GSA Today, James W. Sears of the University of Montana in Missoula advocates a possible Canadian connection for the early Miocene Grand Canyon by arguing for the existence of a “super-river” traceable from headwaters in the southern Colorado Plateau through a proto-Grand Canyon to a delta in the Labrador Sea.

Sears proposes that the river flowed first toward the southwest corner of the Colorado Plateau, and then, in a shift initiated by uplift of the Rio Grande Rift, turned north into Paleogene rifts in the vicinity of Lake Mead. He posits that it then followed northeast-trending grabens across the Idaho and Montana Rockies to the Great Plains and joined the pre-ice age “Bell River” of Canada, which discharged into a massive delta in the Saglek basin of the Labrador Sea.

In this scenario, tectonic faulting beginning 16 million years ago dammed the Miocene Grand Canyon, creating a large lake that existed up to six million years ago. Then volcanism, including the action of the Yellowstone hotspot, cut the river off in Idaho about six million years ago, leading to the eventual capture of the Colorado River by the Gulf of California.

There’s gold in them thar trees

This is a eucalyptus leaf showing traces of gold. -  CSIRO
This is a eucalyptus leaf showing traces of gold. – CSIRO

Eucalyptus trees – or gum trees as they are know – are drawing up gold particles from the earth via their root system and depositing it their leaves and branches.

Scientists from CSIRO made the discovery and have published their findings in the journal Nature Communications.

“The eucalypt acts as a hydraulic pump – its roots extend tens of metres into the ground and draw up water containing the gold. As the gold is likely to be toxic to the plant, it’s moved to the leaves and branches where it can be released or shed to the ground,” CSIRO geochemist Dr Mel Lintern said.

The discovery is unlikely to start an old-time gold rush – the “nuggets” are about one-fifth the diameter of a human hair. However, it could provide a golden opportunity for mineral exploration, as the leaves or soil underneath the trees could indicate gold ore deposits buried up to tens of metres underground and under sediments that are up to 60 million years old.

“The leaves could be used in combination with other tools as a more cost effective and environmentally friendly exploration technique,” Dr Lintern said.

“By sampling and analysing vegetation for traces of minerals, we may get an idea of what’s happening below the surface without the need to drill. It’s a more targeted way of searching for minerals that reduces costs and impact on the environment.

“Eucalyptus trees are so common that this technique could be widely applied across Australia. It could also be used to find other metals such as zinc and copper.”

Using CSIRO’s Maia detector for x-ray elemental imaging at the Australian Synchrotron, the research team was able to locate and see the gold in the leaves. The Synchrotron produced images depicting the gold, which would otherwise have been untraceable.

“Our advanced x-ray imaging enabled the researchers to examine the leaves and produce clear images of the traces of gold and other metals, nestled within their structure,” principal scientist at the Australian Synchrotron Dr David Paterson said.

“Before enthusiasts rush to prospect this gold from the trees or even the leaf litter, you need to know that these are tiny nuggets, which are about one-fifth the diameter of a human hair and generally invisible by other techniques and equipment.”

CSIRO research using natural materials, such as calcrete and laterite in soils, for mineral exploration has led to many successful ore deposit discoveries in regional Australia. The outcomes of the research provide a direct boost to the national economy.

The Consumer’s Guide to Minerals

This digital exclusive is an important reference for students of applied science, geology and economics; practicing engineers and professional geoscientists in government service, environment and sustainability; and those professionals working in the minerals industry or those serving the minerals industry. -  The American Geosciences Institute
This digital exclusive is an important reference for students of applied science, geology and economics; practicing engineers and professional geoscientists in government service, environment and sustainability; and those professionals working in the minerals industry or those serving the minerals industry. – The American Geosciences Institute

The American Geosciences Institute (AGI) announces the release of its latest digital-only publication, “The Consumer’s Guide to Minerals.”

The importance of minerals in our everyday lives cannot be underestimated. “The Consumer’s Guide to Minerals” is a different take on them. Rather than focusing on visual and physical properties, this book explores minerals’ myriad uses in scientific research, manufacturing, medicine and many commercial applications some of which may even shock you. This digital exclusive is an important reference for students of applied science, geology and economics; practicing engineers and professional geoscientists in government service, environment and sustainability; and those professionals working in the minerals industry or those serving the minerals industry.

“The Consumer’s Guide to Minerals” (ISBN 978-0-922152-95-7) is a compilation of monthly articles from EARTH Magazine, edited by Megan Sever and Dr. Christopher M. Keane. The Guide is a collaborative effort between EARTH Magazine and the U.S. Geological Survey.

Mercyhurst, Vanderbilt research targets supervolcanoes

The National Science Foundation has awarded Mercyhurst and Vanderbilt universities a $354,000 grant to engage students in researching one of Earth’s rarest yet deadliest acts — the eruption of a supervolcano.

The Research Experience for Undergraduates (REU) three-year project will take 10-12 students per year into northwest Arizona to study an extinct supervolcano. Students will select their own research pursuit, follow up with lab work at either Mercyhurst or Vanderbilt and, ultimately, present their findings at a national conference.

“The emphasis of this project is to engage students in scientific research, which is consistent with Mercyhurst’s commitment to hands-on learning,” said principal investigator Nick Lang, Ph.D., an assistant professor of geology at Mercyhurst. His project colleague at Vanderbilt is Lily Claiborne, Ph.D.

Lang said the research initiative targets students from diverse backgrounds. “We are looking for talented students, with a particular emphasis on returning veterans, first-generation college students and minorities who will do original research and contribute to the large body of work on supervolcanoes,” he said.

Comprehending what led to supereruptions in the past is essential to understanding and predicting similar events. A supereruption, Lang said, is a volcanic explosion that erupts a volume of material greater than 1,000 km3. This can be about a thousand times larger than normal volcanic eruptions. The deadly 1980 Mount St. Helens explosion, for instance, ejected only 1 cubic km3 of volcanic material, Lang said.

The 10-12 students chosen to participate in each of the three years will hone their geology field skills by investigating the Silver Creek caldera, which produced the Peach Spring Tuff (PST) supereruption nearly 19 million years ago. The PST is exposed over 32,000 kmĀ² of western Arizona, southeastern California and southern Nevada.

Students studying the region’s geologic record will guide their research around questions like: What does a supervolcano look like before it erupts? How and why do large magmatic systems change over time? How does supereruptive magmatism (ex., PST) compare with typical-scale magmatism (ex., Mt.St. Helens)?

Lang said he is eager to get started on the research, which will begin in late December or early January in Arizona followed by another field session in the summer. Students will also complete their lab work during the summer, attending either Mercyhurst or Vanderbilt.

“This is an exciting opportunity for us because these grants (National Science Foundation) are difficult to obtain,” Lang said. “The success rate for a project to be funded is 20 to 25 percent.”

Quake-triggered landslides pose significant hazard for Seattle, new study details potential damage

Locations of each zoom-in are shown on the map of Seattle at right. A) Coastal bluffs in the northern part of Seattle are most affected when soils are saturated. B) There are several areas along the I-5 corridor that are highly susceptible to landsliding for all soil saturation levels, such as the area shown here near the access point to the West Seattle bridge. C) The hillsides in West Seattle along the Duwamish valley are at risk of seismically induced landsliding, such as the area shown here. There are industrial as well as 59 residential buildings that could be affected by runout from landsliding in these areas. D) The coastal bluffs along Puget Sound in West Seattle on the hanging wall of the fault, such as the area shown here, are the most highly susceptible areas to landsliding in the city; numerous residential structures are at risk from both potential landslide source areas and runout. -  Allstadt/BSSA
Locations of each zoom-in are shown on the map of Seattle at right. A) Coastal bluffs in the northern part of Seattle are most affected when soils are saturated. B) There are several areas along the I-5 corridor that are highly susceptible to landsliding for all soil saturation levels, such as the area shown here near the access point to the West Seattle bridge. C) The hillsides in West Seattle along the Duwamish valley are at risk of seismically induced landsliding, such as the area shown here. There are industrial as well as 59 residential buildings that could be affected by runout from landsliding in these areas. D) The coastal bluffs along Puget Sound in West Seattle on the hanging wall of the fault, such as the area shown here, are the most highly susceptible areas to landsliding in the city; numerous residential structures are at risk from both potential landslide source areas and runout. – Allstadt/BSSA

A new study suggests the next big quake on the Seattle fault may cause devastating damage from landslides, greater than previously thought and beyond the areas currently defined as prone to landslides. Published online Oct. 22 by the Bulletin of the Seismological Society of America (BSSA), the research offers a framework for simulating hundreds of earthquake scenarios for the Seattle area.

“A major quake along the Seattle fault is among the worst case scenarios for the area since the fault runs just south of downtown. Our study shows the need for dedicated studies on seismically induced landsliding” said co-author Kate Allstadt, doctoral student at University of Washington.

Seattle is prone to strong shaking as it sits atop the Seattle Basin – a deep sedimentary basin that amplifies ground motion and generates strong seismic waves that tend to increase the duration of the shaking. The broader region is vulnerable to earthquakes from multiple sources, including deep earthquakes within the subducted Juan de Fuca plate, offshore megathrust earthquakes on Cascadia subduction zone and the shallow crustal earthquakes within the North American Plate.

For Seattle, a shallow crustal earthquake close to the city would be most damaging. The last major quake along the Seattle fault was in 900 AD, long before the city was established, though native people lived in the area. The earthquake triggered giant landslides along Lake Washington, causing entire blocks of forest to slide into the lake.

“There’s a kind of haunting precedence that tells us that we should pay attention to a large earthquake on this fault because it happened in the past,” said Allstadt, who also serves as duty seismologist for the Pacific Northwest Seismic Network. John Vidale of University of Washington and Art Frankel of the U.S. Geological Survey (USGS) are co-authors of the study, which was funded by the USGS.

While landslides triggered by earthquakes have caused damage and casualties worldwide, they have not often been the subject of extensive quantitative study or fully incorporated into seismic hazard assessments, say authors of this study that looks at just one scenario among potentially hundreds for a major earthquake in the Seattle area.

Dividing the area into a grid of 210-meter cells, they simulated ground motion for a magnitude 7 Seattle fault earthquake and then further subdivided into 5-meter cells, applying anticipated amplification of shaking due to the shallow soil layers. This refined framework yielded some surprises.

“One-third of the landslides triggered by our simulation were outside of the areas designated by the city as prone to landsliding,” said Allstadt. “A lot of people assume that all landslides occur in the same areas, but those triggered by rainfall or human behavior have a different triggering mechanism than landslides caused by earthquakes so we need dedicated studies.”

While soil saturation — whether the soil is dry or saturated with water – is the most important factor when analyzing the potential impact of landslides, the details of ground motion rank second. The amplification of ground shaking, directivity of seismic energy and geological features that may affect ground motion are very important to the outcome of ground failure, say authors.

The authors stress that this is just one randomized scenario study of many potential earthquake scenarios that could strike the city. While the results do not delineate the exact areas that will be affected in a future earthquake, they do illustrate the extent of landsliding to expect for a similar event.

The study suggests the southern half of the city and the coastal bluffs, many of which are developed, would be hardest hit. Depending upon the water saturation level of the soil at the time of the earthquake, several hundred to thousands of buildings could be affected citywide. For dry soil conditions, there are more than 1000 buildings that are within all hazard zones, 400 of those in the two highest hazard designation zones. The analysis suggests landslides could also affect some inland slopes, threatening key transit routes and impeding recovery efforts. For saturated soil conditions, it is an order of magnitude worse, with 8000 buildings within all hazard zones, 5000 of those within the two highest hazard zones. These numbers only reflect the number of buildings in high-risk areas, not the number of buildings that would necessarily suffer damage.

“The extra time we took to include the refined ground motion detail was worth it. It made a significant difference to our understanding of the potential damage to Seattle from seismically triggered landslides,” said Allstadt, who would like to use the new framework to run many more scenarios to prepare for future earthquakes in Seattle.

Groundbreaking report details status of US secondary Earth science education

The Center for Geoscience Education and Public Understanding at the American Geosciences Institute has released a landmark report on the status of Earth Science education in U.S. middle and high schools, describing in detail significant gaps between identified priorities and lagging practice.

The report, “Earth and Space Sciences Education in U.S. Secondary Schools: Key Indicators and Trends,” offers baseline data on indicators of the subject’s status since the release of the Next Generation Science Standards (NGSS) in April 2013. Establishing clear aims for the subject, the NGSS state that the Earth and Space Sciences should have equal status with the Life Sciences, Physical Sciences, Technology, and Engineering. However, the report shows that school districts and other organizations fail to assign the Earth Sciences this status.

Only one of the nation’s 50 states requires a year-long Earth/Environmental Science course for high school graduation, whereas 32 states require a Life Science course, and 27 require a Physical Science course, according to the report. Only six states require that students are taught Earth Science concepts as part of their graduation requirements. Detailed and analyzed are key indicators including:

  • presence of Earth Science topics in state and national standards;

  • consideration of Earth Science as a graduation requirement;

  • evaluation of Earth Science concepts on high-stakes assessments; and

  • acceptance of Earth Science courses for college admission.

Recommendations for better treatment of Earth Science subject matter include changes in the subject’s relevance to graduation requirements, the discipline’s presence on assessments, designation of Earth Science courses as laboratory courses, and establishment of an Advanced Placement Earth Science program.

The complicated birth of a volcano

Snow storms, ice and glaciers – these are the usual images we associate with the Antarctic. But at the same time it is also a region of fire: the Antarctic continent and surrounding waters are dotted with volcanoes – some of them still active and others extinct for quite some time. The Marie Byrd Seamounts in the Amundsen Sea are in the latter group. Their summit plateaus are today at depths of 2400-1600 meters. Because they are very difficult to reach with conventional research vessels, they have hardly been explored, even though the Marie Byrd Seamounts are fascinating formations. They do not fit any of the usual models for the formation of volcanoes. Now geologists from GEOMAR Helmholtz Centre for Ocean Research Kiel were able to find a possible explanation for the existence of these seamounts on the basis of rare specimens. The study is published in the international journal “Gondwana Research“.

Classic volcanologists differentiate between two types of fire mountains. One type is generated where tectonic plates meet, so the earth’s crust is already cracked to begin with. The other type is formed within the earth’s plates. “The latter are called intraplate volcanoes. They are often found above a so-called mantle plume. Hot material rises from the deep mantle, collects under the earth’s crust, makes its way to the surface and forms a volcano,” said Dr. Reinhard Werner, one of the authors of the current paper. One example are the Hawaiian Islands. But neither of the above models fits the Marie Byrd Seamounts. “There are no plate boundary in the vicinity and no plume underground,” says graduate geologist Andrea Kipf from GEOMAR, first author of the study.

To clarify the origin of the Marie Byrd Seamounts, in 2006 the Kiel scientists participated in an expedition of the research vessel POLARSTEN in the Amundsen Sea. They salvaged rock samples from the seamounts and subjected these to thorough geological, volcanological and geochemical investigations after returning to the home labs. “Interestingly enough, we found chemical signatures that are typical of plume volcanoes. And they are very similar to volcanoes in New Zealand and the Antarctic continent,” says geochemist Dr. Folkmar Hauff, second author of the paper.

Based on this finding, the researchers sought an explanation. They found it in the history of tectonic plates in the southern hemisphere. Around 100 million years ago, remains of the former supercontinent Gondwana were located in the area of present Antarctica. A mantle plume melted through this continental plate and cracked it open. Two new continents were born: the Antarctic and “Zealandia”, with the islands of New Zealand still in evidence today. When the young continents drifted in different directions away from the mantle plume, large quantities of hot plume material were attached to their undersides. These formed reservoirs for future volcanic eruptions on the two continents. “This process explains why we find signatures of plume material at volcanoes that are not on top of plumes,” says Dr. Hauff.

But that still does not explain the Marie Byrd Seamounts because they are not located on the Antarctic continent, but on the adjacent oceanic crust instead. “Continental tectonic plates are thicker than the oceanic ones. This ensures, among other things, differences in temperature in the underground,” says volcanologist Dr. Werner. And just as air masses of different temperatures create winds, the temperature differences under the earth’s crust generate flows and movements as well. Thus the plume material, that once lay beneath the continent, was able to shift under the oceanic plate. With disruptions due to other tectonic processes, there were cracks and crevices which allowed the hot material to rise, turn into magma and then- about 60 million years ago – allowed the Marie Byrd Seamounts to grow. “This created islands are comparable to the Canary Islands today,” explains Andrea Kipf. “Some day the volcanoes became extinct again, wind and weather eroded the cone down to sea level, and other geological processes further eroded the seamounts. Finally, the summit plateaus arrived at the level that we know today,” the PhD student describes the last step of the development.

Based on the previously little investigated Marie Byrd Seamounts, the researchers were able to show another example of how diverse and complex the processes are, that can cause volcanism. “We are still far from understanding all of these processes. But with the current study, we can contribute a small piece to the overall picture,” says Dr. Werner.