DALLAS (SMU) – Leaf fossils from Ethiopia’s Mush Valley that date back nearly 22 million years have been found by SMU’s Earth Science professors Bonnie Jacobs and Neil J. Tabor and a dozen other international scientists.
The Mush Valley is the first site in Africa to produce an assemblage of some 2,400 leaves from that time interval, and the first to be studied using multiple lines of evidence, including associated microscopic fossils and chemical constituents, that tell us details about the ancient ecosystem.
Paleobotanical remains that an international team found in Ethiopia’s Mush Valley.
Scientists can use data from the study to answer fundamental questions, like what climate change may look like in the future. Specifically, climate scientists can take information from the study, along with other data, to test models used to estimate future global climate change.
“The past helps us to understand how ecological processes operate under conditions so different from now. It is like the Earth has done experiments for us,” said Jacobs, a world-renowned paleobotanist at SMU (Southern Methodist University).
In addition, using fossils to learn more about what Africa’s prehistoric ecosystems were like can provide context for events in the past, such as when a land bridge developed between Africa and Eurasia 24 million years ago or the environment for primate precursors to the human family.
The fossils found in this study span an interval of 60,000 years during the early Miocene Epoch, which began 23 million years ago. Ellen D. Currano, a paleoecologist at the University of Wyoming, was the lead author of the study. It was published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.
You can read more about the work that Jacobs, Currano and the international colleagues have been doing in the Mush Valley here.
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Leakage in Ken Regan field could have contaminated groundwater for livestock and irrigation between 2007 and 2011
DALLAS (SMU) – Geophysicists at SMU say that evidence of leak occurring in a West Texas wastewater disposal well between 2007 and 2011 should raise concerns about the current potential for contaminated groundwater and damage to surrounding infrastructure.
SMU geophysicist Zhong Lu and the rest of his team believe the leak happened at a wastewater disposal well in the Ken Regan field in northern Reeves County, which could have leaked toxic chemicals into the Rustler Aquifer. The same team of geophysicists at SMU has revealed that sinkholes are expanding and forming in West Texas at a startling rate.
a) Coverage of the ALOS PALSAR scenes used (white box). Black line shows the boundary of the Ken Regan field. Dark green line and light green line represent the boundaries of the Rustler Aquifer and Pecos Valley Aquifer in Texas, respectively. Red star represents the epicenter of the earthquake that occurred in May 2018. Blue circle represents the groundwater well for livestock drawing from the Rustler Aquifer in this area. Blue triangles are wells, which provide groundwater leveling records. (b) Vertical deformation (cm/yr) (in the red box in Fig. 1a) estimated from InSAR. Green circles with and without arrows indicate active injection/disposal wells in the Ken Regan field and oil production wells within 1.5 km from the deformation center during the research period, respectively. Purple circle represents the groundwater which provides groundwater quality records. Source: Zhong Lu
Wastewater is a byproduct of oil and gas production. Using a process called horizontal drilling, or “fracking,” companies pump vast quantities of water, sand and chemicals far down into the ground to help extract more natural gas and oil. With that gas and oil, however, come large amounts of wastewater that is injected deep into the earth through disposal wells.
Federal and state oil and gas regulations require wastewater to be disposed of at a deep depth, typically ranging from about 1,000 to 2,000 meters deep in this region, so it does not contaminate groundwater or drinking water. A small number of studies suggest that arsenic, benzene and other toxins potentially found in fracking fluids may pose serious risks to reproductive and development health.
Even though the leak is thought to have happened between 2007 and 2011, the finding is still potentially dangerous, said Weiyu Zheng, a Ph.D. student at SMU (Southern Methodist University) who led the research.
“The Rustler Aquifer, within the zone of the effective injection depth, is only used for irrigation and livestock but not drinking water due to high concentrations of dissolved solids. Wastewater leaked into this aquifer may possibly contaminate the freshwater sources,” Zheng explained.
“If I lived in this area, I would be a bit worried,” said Lu, professor of Shuler-Foscue Chair at SMU’s Roy M. Huffington Department of Earth Sciences and the corresponding researcher of the findings.
He also noted that leaking wastewater can do massive damage to surrounding infrastructure. For example, oil and gas pipelines can be fractured or damaged beneath the surface, and the resulting heaving ground can damage roads and put drivers at risk.
SMU geophysicists say satellite radar imagery indicates a leak in the nearby disposal well happened because of changes shown to be happening in the nearby Ken Regan field: a large section of ground, five football fields in diameter and about 230 feet from the well, was raised nearly 17 centimeters between 2007 and 2011. In the geology world, this is called an uplift, and it usually happens where parts of the earth have been forced upward by underground pressure.
Lu said the most likely explanation for that uplift is that leakage was happening at the nearby well.
“We suspect that the wastewater was accumulated at a very shallow depth, which is quite dramatically different from what the report data says about that well,” he said.
Only one wastewater disposal well is located in close proximity to the uplifted area of the Ken Regan field. The company that owns it reported the injection of 1,040 meters of wastewater deep into the disposal well in Ken Regan. That well is no longer active.
But a combination of satellite images and models done by SMU show that water was likely escaping at a shallower level than the well was drilled for.
And the study, which was published in the Nature publication Scientific Reports, estimates that about 57 percent of the injected wastewater went to this shallower depth. At that shallower depth, the wastewater–which typically contains salt water and chemicals–could have mixed in with groundwater from the nearby Rustler Aquifer. Drinking water doesn’t come from the Rustler Aquifer, which spans seven counties. But the aquifer does eventually flow into the Pecos River, which is a drinking source.
The scientists made the discovery of the leak after analyzing radar satellite images from January 2007 to March 2011. These images were captured by a read-out radar instrument called Phased Array type L-band Synthetic Aperture Radar (PALSAR) mounted on the Advanced Land Observing Satellite, which was run by the Japan Aerospace Exploration Agency
With this technology called interferometric synthetic aperture radar, or InSAR for short, the satellite radar images allow scientists to detect changes that aren’t visible to the naked eye and that might otherwise go undetected. The satellite technology can capture ground deformation with a precision of sub-inches or better, at a spatial resolution of a few yards or better over thousands of miles, say the researchers.
Lu and his team also used data that oil and petroleum companies are required to report to the Railroad Commission of Texas (Texas RRC), as well as sophisticated hydrogeological models that mapped out the distribution and movement of water underground as well as rocks of the Earth’s crust.
“We utilized InSAR to detect the surface uplift and applied poroelastic finite element models to simulate displacement fields. The results indicate that the effective injection depth is much shallower than reported,” Zheng said. “The most reasonable explanation is that the well was experiencing leakage due to casing failures and/or sealing problem(s).”
“One issue is that the steel pipes can degrade as they age and/or wells may be inadequately managed. As a result, wastewater from failed parts can leak out,” said Jin-Woo Kim, research scientist with Lu’s SMU Radar Laboratory and a co-author of this study.
The combination of InSAR imagery and modeling done by SMU gave the scientists a clear picture of how the uplift area in Regan field developed.
Lu, who is world-renowned for leading scientists in using InSAR applications to detect surface changes, said these types of analysis are critical for the future of oil-producing West Texas.
“Our research that exploits remote sensing data and numerical models provides a clue as to understanding the subsurface hydrogeological process responding to the oil and gas activities. This kind of research can further be regarded as an indirect leakage monitoring method to supplement current infrequent leakage detection,” Zheng said.
“It’s very important to sustain the economy of the whole nation. But these operations require some checking to guarantee the operations are environmentally-compliant as well,” Lu said.
Co-author Dr. Syed Tabrez Ali from AIR-Worldwide in Boston also contributed to this study.
This research was sponsored by the NASA Earth Surface and Interior Program and the Schuler-Foscue endowment at SMU.
Previously, Kim and Lu used satellite radar imaging to find that two giant sinkholes near Wink, Texas—two counties over from the Ken Regan uplift—were likely just the tip of the iceberg of ground movement in West Texas. Indeed, they found evidence that large swaths of West Texas oil patch were heaving and sinking at alarming rates. Decades of oil production activities in West Texas appears to have destabilized localities in an area of about 4,000 square miles populated by small towns like Wink, roadways and a vast network of oil and gas pipelines and storage tanks.
SMU is the nationally ranked global research university in the dynamic city of Dallas. SMU’s alumni, faculty and nearly 12,000 students in eight degree-granting schools demonstrate an entrepreneurial spirit as they lead change in their professions, communities and the world.
A new analysis of historical seismic data conducted by The University of Texas at Austin, SMU and other academies has found that earthquake activity in West Texas around Pecos has increased dramatically since 2009.
The study, published Nov. 4, 2019, in the Journal of Geophysical Research: Solid Earth, is important because it leverages old, unmined data to track seismic activity over nearly the past two decades – much further back than other studies— to show that activity has increased during the past decade in an area of the Permian Basin that is being heavily developed for oil and gas. Although researchers have generally thought that to be true, the statewide TexNet earthquake monitoring system has been gathering data since only 2017, making it impossible to definitely determine when the cluster of seismic activity around Pecos really began.
The researchers were able to extend the seismic record of the area by turning to the older TXAR system near Lajitas about 150 miles to the south. TXAR is an array of 10 seismographs installed in the 1990s by scientists at SMU (Southern Methodist University) to help track nuclear testing across the world, said lead author Cliff Frohlich, a senior research scientist emeritus at the University of Texas Institute for Geophysics (UTIG).
“Especially for these West Texas earthquakes, we would like to get some information about when they started,” Frohlich said. “I really saw this as a way to bridge the gap before TexNet.”
The TXAR system is some distance from Pecos, but Frohlich said the equipment is highly sensitive and that the area is remote and seismically very quiet, making the system perfect for picking up vibrations from explosions across the world or from earthquakes 150 miles away. Frohlich worked with Chris Hayward, director of SMU’s Geophysics Research Program, to create a method to derive the earthquake data from the international data TXAR collects and build an earthquake catalog for the Delaware Basin near Pecos from 2000 to 2017.
By analyzing data from 2000 to 2017, scientists were able to document more than 7,000 seismic events near Pecos that were determined by the team to be earthquakes. Data on these seismic events had to be manually reviewed to ensure they were in fact earthquakes and not a false detection. This was done by Frohlich and Julia Rosenblit, who was an SMU intern at the time.
Multiple events first started occurring in 2009, when 19 earthquakes of at least magnitude 1 were documented. The rate increased over time, with more than 1,600 earthquakes of magnitude 1 or greater in 2017. Most were so small that no one felt them.
The study shows a correlation between earthquake activity in the area and an increase in oil and gas activity but doesn’t make an effort to directly tie the two together as other studies have done.
“West Texas now has the highest seismicity rates in the state,” said Heather DeShon, study co-author and associate professor at SMU’s Roy M. Huffington Department of Earth Sciences. “What remained uncertain is when the earthquakes actually started. This study addresses that.”
This study is the latest in a comprehensive effort to determine what is causing an increase in seismic activity in Texas and how oil and gas operations can be managed to minimize that human-induced element. The state approved the TexNet system in 2015, which is operated in tandem with research efforts by the Center for Integrated Seismicity Research (CISR).
Co-author Peter Hennings, who leads CISR and is a Senior Research Scientist at the UT Bureau of Economic Geology said that fundamental research like this latest study is vital when trying to unravel such a complicated problem.
“The obvious next step is exactly what the University of Texas is doing – conducting these careful studies on the relationship between earthquakes and their human and natural causes to build an integrated understanding,” Hennings said.
SMU seismologists have also been the lead or co-authors of a series of studies on Texas earthquakes. For instance, UT Austin and SMU found that earthquakes triggered by human activity have been happening in Texas since 1925, and they have been widespread throughout the state ever since. In addition, SMU research showed that many of the Dallas-Fort Worth earthquakes were triggered by increases in pore pressure–the pressure of groundwater trapped within tiny spaces inside rocks in the subsurface.
The Bureau of Economic Geology and UTIG are units of the UT Jackson School of Geosciences. Scientists from SMU, Portland State University, the University of Oklahoma and the French institute IFREMER also worked on the study.
Volcanic eruptions and their ash clouds pose a significant hazard to population centers and air travel, especially those that show few to no signs of unrest beforehand. Geologists are now using a technique traditionally used in weather and climate forecasting to develop new eruption forecasting models. By testing if the models are able to capture the likelihood of past eruptions, the researchers are making strides in the science of volcanic forecasting.
The study, published in the journal Geophysical Research Letters, examined the eruption history of the Okmok volcano in Alaska. In 2008, a large eruption produced an ash plume that extended approximately 1 mile into the sky over the Aleutian Islands – posing a significant hazard to aircraft engines along a route that transports roughly 50,000 people between Asia and North America each day, the researchers said.
“The 2008 eruption of Okmok came as a bit of surprise,” said University of Illinois graduate student and lead author Jack Albright. “After an eruption that occurred in 1997, there were periods of slight unrest, but very little seismicity or other eruption precursors. In order to develop better forecasting, it is crucial to understand volcanic eruptions that deviate from the norm.”
Geologists typically forecast eruptions by looking for established patterns of preeruption unrest such as earthquake activity, groundswell and gas release, the researchers said. Volcanoes like Okmok, however, don’t seem to follow these established patterns.
To build and test new models, the team utilized a statistical data analysis technique developed after World War II called Kalman filtering.
“The version of Kalman filtering that we used for our study was updated in 1996 and has continued to be used in weather and climate forecasting, as well as physical oceanography,” said U. of I. geology professor Patricia Gregg, a co-author of the study that included collaborators from SMU (Southern Methodist University) and Michigan State University. “We are the first group to use the updated method in volcanology, however, and it turns out that this technique works well for the unique unrest that led up to Okmok’s 2008 eruption.”
One of those unique attributes is the lack of increased seismicity before the eruption, the researchers said. In a typical preeruption sequence, it is hypothesized that the reservoir under the volcano stays the same size as it fills with magma and hot gases. That filling causes pressure in the chamber to increase and the surrounding rocks fracture and move, causing earthquakes.
“In the 2008 eruption, it appears that the magma chamber grew larger to accommodate the increasing pressure, so we did not see the precursor seismic activity we would expect,” Albright said. “By looking back in time with our models, or hindcasting, we can now observe that stress had been building up in the rocks around the chamber for weeks, and the growth of the magma system ultimately led to its failure and eruption.”
This type of backward and forward modeling allows researchers to watch a volcanic system evolve over time. “While we stopped our analysis after the 2008 eruption, we are now able to propagate this new model forward in time, bring it to present day, and forecast where Okmok volcano is heading next,” Gregg said.
The researchers posit that these models will continue to find other less-recognized eruption precursors, but acknowledge that every volcano is different and that the models must be tailored to fit each unique system.
The volcano forecasting technique used in this study was based on volcano deformation data from GPS and satellite radars. Geophysicist Zhong Lu, a professor in the Roy M. Huffington Department of Earth Sciences at SMU and a global expert in satellite radar imagery analysis, processed the satellite radar images and provided the volcano deformation maps for this research.
The U. of I. team is working in collaboration with researchers from Alaska Volcano Observatory and SMU to help build a stronger forecasting system for the Aleutian Islands area. The researchers received $541,921 in grant money from NASA for the work in early 2019.
Study sheds light on how the way our ancestors fed themselves changed our ecosystem
DALLAS (SMU) – Humans started making an impact on the global ecosystem through intensive farming much earlier than previously estimated, according to a new study published in the journal Science.
Evidence of the earliest domesticated plants and animals dates back to around 10,000 years ago. But findings from a team of more than 250 scientists, including two from SMU (Southern Methodist University), show that by 3,000 years ago our ancestors had dramatically changed the world to grow food.
“Our study shows in detail the progression from the origins of agriculture to its spread around the world,” said SMU anthropologist Mark D. McCoy. “It turns out that earth science models are probably too conservative, and intensive reshaping of the environment for food production was common by thousands of years before the onset of the kind of industrial scale farming we see today.
“That is important because over the time periods discussed, humans became the major force shaping ecosystems around the world,” McCoy said.
The new global assessment by the ArchaeoGLOBE Project also shows that scientists have previously underestimated the impact of early human land use.
Crowdsourcing the Map
Led by archeologist Lucas Stephens, a researcher affiliated with the Max Planck Institute for the Science of Human History, ArchaeoGLOBE used a crowdsourcing approach, inviting experts in ancient land use to contribute to a questionnaire on 146 regions (covering all continents except Antarctica) at ten historical time intervals to assess and integrate archaeological knowledge at a global scale. The result was a complete, though uneven, meta-analysis of global land use over time.
Significantly, the study also reveals that hunting and gathering was more varied and complex than originally thought, helping archeologists to recognize that foragers “may have initiated dramatic and sometimes irreversible environmental change.” Intensive forms of agriculture reported around the world included activities like clearing land, creating fields that were fixed on the landscape, raising large herds of animals, and putting increasing amounts of effort into growing food.
SMU anthropologist and ArchaeoGLOBE team member K. Ann Horsburgh notes the rise in agriculture and livestock is primarily due to growing populations needing to be fed.
“Food production such as agriculture and pastoralism, when compared with foraging in the same environment, is linked to a faster population growth and can sustain higher population densities,” said Horsburgh.
Horsburgh, Assistant Professor of Anthropology, and McCoy, Associate Professor of Anthropology, provided information on land use in Africa and the remote islands of the Pacific, respectively. McCoy also brought his expertise in geospatial technology to study how people in the past inhabited and shaped the world around them, while Horsburgh brought her knowledge of ancient DNA to retrace the spread of domesticated animals.
Mapping Ancient Migrations
The map could provide new light on how the spread of farming and herding were linked to major migrations in human prehistory.
“This is first time that regional expertise on ancient land use has been synthesized on this scale,” Horsburgh said. “That matters because we know that although the shift from foraging to farming tends to be a ‘one-way’ transition, it did not progress the same way around the world. The details of how it did progress has shaped everything from our diets to the languages we speak today.”
Horsburgh went on to say, “What remains the topic of intense study is how much of the transition is food producers spreading and displacing foragers, and how much is it foragers adopting or marrying into food producing groups, or some other scenario. Most of this was done in the absence of written records, so it is up to anthropology to sort things out.”
“The natural next step for this revised model of the spread of different types, and intensities, of land use is to compare them with human genetics and linguistics and integrate these findings into the big story of humanity,” said Horsburgh.
SMU is the nationally ranked global research university in the dynamic city of Dallas. SMU’s alumni, faculty and nearly 12,000 students in seven degree-granting schools demonstrate an entrepreneurial spirit as they lead change in their professions, communities and the world.
