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TRANSCRIPT
Atlanta Geological Society Newsletter
ODDS AND ENDS Dear AGS members, As we are coming into the end of the year, there are a few items of Society business to take care of during this month’s meeting. November is the month for officer elections. Unfortunately, I was not able to attend last month’s paleontology lecture as I was called away on business. I’d like to know more about Dinosaurs in the Southeast. The October meeting is the month that officer nominations are opened. We have a simple system, no primaries, no debates but we do need folks to nominated to fill the four offices; President, Vice-President, Treasurer and Secretary. Fortunately, we will have an opportunity to accept nominations prior to the elections at the beginning of our meeting. None of the jobs are really taxing and it is rewarding to serve the geologic community in general. Please give it some consideration. Also, we could have a bit of a discussion about our goals and needs for 2018. Last fall we had a good discussion and I took a bunch of notes. That is how I pulled together the operating plan that we used this year to make our improvements. I pledge to revise that again for next year as that seems like a good thing for the (at least current) President to do. It was a very useful exercise and produced tangible results in the Society’s operations. But we need your input so that it reflects the interests of the members. As this is the Thanks giving season, I am thankful for the Atlanta Geological Society. It is a chance to have some fellowship with like-minded folks, eating pizza among the dinosaurs of Fernbank’s great rotunda. Enough for now. Time to go for some turkey. Hope to see you Tuesday! Ben Bentkowski, President
November Meeting
Join us Tuesday, November 28, 2017 at the Fernbank Museum of Natural History,
760 Clifton Road NE, Atlanta GA. The meeting/dinner starts at 6:30 pm and the
meeting starts approximately 7 p.m.
This month’s speaker will be Dr. Stephen
Henderson from Emory University.
Please come out, enjoy a bite to eat, the camaraderie, an interesting presentation and perhaps some discussion on the importance of accurate mineral characterization. Also,
the differences that can exist between mineralogical, industrial and regulatory
definitions for minerals.
Keep up to date with the AGS at:
www.atlantageologicalsociety.org or at Facebook
facebook.com/Atlanta-Geological-Society
Page 2 AGS November 2017
NASA’s Curiosity Rover Finds Mineral Hematite on Mars
NASA’s Curiosity rover has found spectral evidence of an iron-oxide mineral called hematite (Fe2O3) on a rock near Mount Sharp in Gale Crater, Mars. In an area on Mars’ ‘Vera Rubin Ridge’ where the Curiosity team sought to determine whether dust coatings are hiding rocks’ hematite content, the rover found a promising target — a rock called ‘Christmas Cove.’ On September 16, 2017, during the 1,118th Martian day of Curiosity’s work on the planet, the rover’s wire-bristled brush — the Dust Removal Tool — brushed an area about 2.5 inches (6 cm) across. Curiosity’s Mars Hand Lens Imager (MAHLI) took an image of the freshly brushed area later the same day.
“Removing dust from part of the Christmas Cove target was part of an experiment to check whether dust is subduing the apparent indications of hematite in some of the area’s bedrock,” the rover-team researchers explained. “The brushed area’s purplish tint in an image from the MAHLI was characteristic of fine-grained hematite, an iron-oxide mineral that can provide information about ancient environmental conditions.” “Brushing of this target also exposed details in the fine layering and bright veins within the bedrock of this part of Vera Rubin Ridge.”
The next day — September 17, 2017 — observations with the rover’s Mast Camera (Mastcam) and its Chemistry and Camera (ChemCam) confirmed a strong presence of hematite. “ChemCam sometimes zaps rocks with a laser, but can also be used, as in this case, in a ‘passive’ mode,” the scientists said. “In this type of investigation, the instrument’s telescope delivers to spectrometers the sunlight reflected from a small target point.”
Read more at http://www.sci-news.com/space/curiosity-hematite-mars-05420.html
This false-color image demonstrates how use of special filters available on Curiosity’s Mastcam camera can reveal the presence of certain minerals in target rocks. It is a composite of images taken through three ‘science’ filters chosen for making hematite stand out as exaggerated purple. Mastcam’s narrow-band filters used for this view help to increase spectral contrast, making blues bluer and reds redder, particularly with the processing used to boost contrast in each of the component images of this composite. Fine-grained hematite preferentially absorbs sunlight around in the green portion of the spectrum around 527 nm. That gives it the purple look from a combination of red and blue light reflected by the hematite and reaching the camera through the other two filters. Bright lines within the rocks are fractures filled with calcium sulfate minerals. Image credit: NASA / JPL-Caltech / MSSS.
AGS November 2017 Page 3
Recurring Martian Streaks: Flowing Sand, Not Water?
Dark features on Mars previously considered evidence for subsurface flowing of water are interpreted by new research as granular flows, where grains of sand and dust slip downhill to make dark streaks, rather than the ground being darkened by seeping water. Continuing examination of these still-perplexing seasonal dark streaks with a powerful camera on NASA's Mars Reconnaissance Orbiter (MRO) shows they exist only on slopes steep enough for dry grains to descend the way they do on faces of active dunes.
The findings published today in Nature Geoscience argue against the presence of enough liquid water for microbial life to thrive at these sites. However, exactly how these numerous flows begin and gradually grow has not yet been explained. Authors of the report propose possibilities that include involvement of small amounts of water, indicated by detection of hydrated salts observed at some of the flow sites. These features have evoked fascination and controversy since their 2011 discovery, as possible markers for unexpected liquid water or brine on an otherwise dry planet. They are dark streaks that extend gradually downhill in warm seasons, then fade away in winter and reappear the next year. On Earth, only seeping water is known to have these behaviors, but how they form in the dry Martian environment remains unclear.
Many thousands of these Martian features, collectively called "recurring slope lineae" or RSL, have been identified in more than 50 rocky-slope areas, from the equator to about halfway to the poles. "We've thought of RSL as possible liquid water flows, but the slopes are more like what we expect for dry sand," said Colin Dundas of the U.S. Geological Survey's Astrogeology Science Center in Flagstaff, Arizona. "This new understanding of RSL supports other evidence that shows that Mars today is very dry."
Dundas is lead author of the report, which is based on observations with the High Resolution Imaging Science Experiment (HiRISE) camera on MRO. The data include 3-D models of slope steepness using pairs of images for stereo information. Dundas and co-authors examined 151 RSL features at 10 sites. The RSL are almost all restricted to slopes steeper than 27 degrees. Each flow ends on a slope that matches the dynamic "angle of repose" seen in the slumping dry sand of dunes on Mars and Earth. A flow due to liquid water should readily extend to less steep slopes. "The RSL don't flow onto shallower slopes, and the lengths of these are so closely correlated with the dynamic angle of repose, it can't be a coincidence," said HiRISE Principal Investigator Alfred McEwen at the University of Arizona, Tucson, a co-author of the new report.
The seasonal dark streaks have been thought of as possible evidence for biologically significant liquid water—sufficient water for microbial life—though explaining how so much liquid water could exist on the surface in Mars' modern environment would be challenging. A granular-flow explanation for RSL fits with the earlier understanding that the surface of modern Mars, exposed to a cold, thin atmosphere, lacks flowing water. A 2016 report also cast doubt on possible sources of underground water at RSL sites. Liquid water on today's Mars may be limited to traces of dissolved moisture from the atmosphere and thin films, which are challenging environments for life as we know it.
However, RSL remain puzzling. Traits with uncertain explanations include their gradual growth, their seasonal reappearance, their rapid fading when inactive, and the presence of hydrated salts, which have water molecules bound into their crystal structure.
The new report describes possible connections between these traits and how RSL form. For example, salts can become hydrated by pulling water vapor from the atmosphere, and this process can form drops of salty water. Seasonal changes in hydration of salt-containing grains might result in some trigger mechanism for RSL grain
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Recurring Martian Streaks: Flowing Sand, Not Water? (Continued)
flows, such as expansion, contraction, or release of some water. Darkening and fading might result from changes in hydration. If atmospheric water vapor is a trigger, then a question is why the RSL appear on some slopes but not others. "RSL probably form by some mechanism that is unique to the environment of Mars," McEwen said, "so they represent an opportunity to learn about how Mars behaves, which is important for future surface exploration."
"Full understanding of RSL is likely to depend upon on-site investigation of these features," said MRO Project Scientist Rich Zurek of NASA's Jet Propulsion Laboratory, Pasadena, California. "While the new report suggests that RSL are not wet enough to favor microbial life, it is likely that on-site investigation of these sites will still require special procedures to guard against introducing microbes from Earth, at least until they are definitively characterized. In particular, a full explanation of how these enigmatic features darken and fade still eludes us. Remote sensing at different times of day could provide important clues."
Read more at: https://phys.org/news/2017-11-recurring-martian-streaks-sand.html#jCp
Added Arctic Data Shows Global Warming Didn't Pause
Missing Arctic temperature data, not Mother Nature, created the seeming slowdown of global warming from 1998 to 2012, according to a new study in the journal Nature Climate Change. A University of Alaska Fairbanks professor and his colleagues in China constructed the first data set of surface temperatures from across the world that significantly improves representation of the Arctic during the "global warming hiatus."
Xiangdong Zhang, an atmospheric scientist with UAF's International Arctic Research Center, said he collaborated
This inner slope of a Martian crater has several of the seasonal dark streaks called "recurrent slope lineae," or RSL, that a November 2017 report interprets as granular flows, rather than darkening due to flowing water. The image is from the HiRISE camera on NASA's Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/UA/USGS.
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Added Arctic Data Shows Global Warming Didn't Pause (Continued)
with colleagues at Tsinghua University in Beijing and Chinese agencies studying Arctic warming to analyze temperature data collected from buoys drifting in the Arctic Ocean. "We recalculated the average global temperatures from 1998-2012 and found that the rate of global warming had continued to rise at 0.112C per decade instead of slowing down to 0.05C per decade as previously thought," said Zhang. The new data also improved estimates of the global warming and the Arctic warming rate.
"We estimated a new rate of Arctic warming at 0.659 C per decade from 1998-2014. Compared with the newly estimated global warming rate of 0.130 C per decade, the Arctic has warmed more than five time the global average," said Zhang. The team developed new methods of incorporating the Arctic temperature data into global temperature data so that they could better estimate the average temperatures. Most current estimates use global data that tend to represent a long time span and provide good coverage of a global geographic area. But the remote Arctic lacks a robust network of instruments to collect temperature data.
To improve the dataset in time and space, the team relied on temperature data collected from the International Arctic Buoy Program at the University of Washington. For global data, the team used newly corrected sea surface temperatures from the National Oceanic and Atmospheric Administration. Zhang said this study expands on NOAA research and other recent studies that have either supported or refuted the idea of a "global warming hiatus" by reestimating the average global temperatures during that time period with more accurate and representative data.
The global warming hiatus is a much-debated topic among climate researchers. Some scientists theorized that an unusually warm El Niño in the years 1997-1998 and an extended period afterwards without occurrence of El Nino in the tropical Pacific Ocean may have disrupted the rate of global warming. The Earth's average global temperatures have been rising over the past century and accelerating as more human produced carbon dioxide enters and lingers in the atmosphere, which is why the idea of "global warming hiatus" seemed baffling.
But the new data set and resulting estimates show conclusively that global warming did not take a break, said Zhang. It also highlights the importance of considering the Arctic when thinking about climate change. Until recently, Zhang said, many scientists didn't consider the Arctic big enough to greatly influence the average global temperatures. "The Arctic is remote only in terms of physical distance," he said. "In terms of science, it's close to every one of us. It's a necessary part of the equation and the answer affects us all."
These figures show the global warming rates with the incorporated Arctic data.
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It Might Be Possible to Refreeze The Icecaps to Slow Global Warming
One of the most worrisome aspects of climate change is the role played by positive feedback mechanisms. In addition to global temperatures rising because of increased carbon dioxide and greenhouse gas emissions, there is the added push created by deforestation, ocean acidification, and (most notably) the disappearance of the Arctic polar ice cap. However, according to a new study by a team of researchers from the School of Earth and Space Exploration at Arizona State University, it might be possible to refreeze parts of the Arctic ice sheet. Through a geoengineering technique that would rely on wind-powered pumps, they believe one of the largest positive feedback mechanisms on the planet can be neutralized.
Their study, titled "Arctic Ice Management", appeared recently in Earth's Future, an online journal published by the American Geophysical Union. As they indicate, the current rate at which Arctic ice is disappearing it quite disconcerting. Moreover, humanity is not likely to be able to combat rising global temperatures in the coming decades without the presence of the polar ice cap. Of particular concern is the rate at which polar ice has been disappearing, which has been quite pronounced in recent decades. The rate of loss has been estimated at being between 3.5 percent and 4.1 percent per decade, with in an overall decrease of at least 15 percent since 1979 (when satellite measurements began). To make things worse, the rate at which ice is being lost is accelerating.
A drastic decrease in arctic sea ice since satellite imaging of the polar ice cap began. Credit: NASA.
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It Might Be Possible to Refreeze The Icecaps to Slow Global Warming (Continued)
From a baseline of about 3 percent per decade between 1978-1999, the rate of loss since the 2000s has climbed considerably – to the point that the extent of sea-ice in 2016 was the second lowest ever recorded. As they state in their Introduction (and with the support of numerous sources), the problem is only likely to get worse between now and the mid-21st century: "Global average temperatures have been observed to rise linearly with cumulative CO2 emissions and are predicted to continue to do so, resulting in temperature increases of perhaps 3°C or more by the end of the century. The Arctic region will continue to warm more rapidly than the global mean. Year-round reductions in Arctic sea ice are projected in virtually all scenarios, and a nearly ice-free (<106 km2 sea-ice extent for five consecutive years) Arctic Ocean is considered "likely" by 2050 in a business-as-usual scenario."
One of the reasons the Arctic is warming faster than the rest of the planet has to do with strong ice-albedo feedback. Basically, fresh snow ice reflects up to 90 percent of sunlight while sea ice reflects sunlight with albedo up to 0.7, whereas open water (which has an albedo of close to 0.06) absorbs most sunlight. Ergo, as more ice melts, the more sunlight is absorbed, driving temperatures in the Arctic up further.
To address this concern, the research team – led by Steven J. Desch, a professor from the School of Earth and Space Exploration – considered how the melting is connected to seasonal fluctuations. Essentially, the Arctic sea ice is getting thinner over time because new ice (aka. "first-year ice"), which is created with every passing winter, is typically just 1 meter (3.28 ft) thick.
Arctic sea-ice extent (area covered at least 15% by sea ice) in September 2007 (white area). The red curve denotes the 1981–2010 average. Credit: National Snow and Ice Data Center.
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It Might Be Possible to Refreeze The Icecaps to Slow Global Warming (Continued)
Ice that survives the summer in the Arctic is capable of growing and becoming "multiyear ice", with a typical thickness of 2 to 4 meters (6.56 to 13.12 ft). But thanks to the current trend, where summers are getting progressively warmer, "first-year ice" has been succumbing to summer melts and fracturing before it can grow. Whereas multiyear ice comprised 50 to 60 percent of all ice in the Arctic Ocean in the 1980s, by 2010, it made up just 15 percent. With this in mind, Desch and his colleagues considered a possible solution that would ensure that "first-year ice" would have a better chance of surviving the summer. By placing machines that would use wind power to generate pumps, they estimate that water could be brought to the surface over the course of an Arctic winter, when it would have the best chance of freezing.
Based on calculations of wind speed in the Arctic, they calculate that a wind turbine with 6-meter diameter blades would generate sufficient electricity so that a single pump could raise water to a height of 7 meters, and at a rate of 27 metric tons (29.76 US tons) per hour. The net effect of this would be thicker sheets of ice in the entire affected area, which would have a better chance of surviving the summer. Over time, the negative feedback created by more ice would cause less sunlight to be absorbed by the Arctic ocean, thus leading to more cooling and more ice accumulation. This, they claim, could be done on a relatively modest budget of $500 billion per year for the entire Arctic, or $50 billion per year for 10 percent of the Arctic.
While this may sound like a huge figure, they are quick to point out that the cast covering the entire Arctic with ice-creating pumps – which could save trillions in GDP and countless lives- is equivalent to just 0.64 percent of current world gross domestic product (GDP) of $78 trillion. For a country like the United States, it represents just 13 percent of the current federal budget ($3.8 trillion). And while there are several aspects of this proposal that still need to be worked out (which Desch and his team fully acknowledge), the concept does appear to be theoretically sound. Not only does it take into account the way seasonal change and climate change are linked in the Arctic, it acknowledges how humanity is not likely to be able to address climate change without resorting to geoengineering techniques. And since Arctic ice is one of the most important things when it comes to regulating global temperatures, it makes perfect sense to start here.
Read more at: https://phys.org/news/2017-02-refreeze-icecaps-global.html#jCp
USGS Study Finds Unconventional Oil and Gas Production Not Currently Affecting Drinking Water Quality
A new U.S. Geological Survey study shows unconventional oil and gas production in some areas of Arkansas, Louisiana, and Texas is not currently a significant source of methane or benzene to drinking water wells. These production areas include the Eagle Ford, Fayetteville, and Haynesville shale formations, which are some of the largest sources of natural gas in the country and have trillions of cubic feet of gas.
The USGS examined 116 domestic and public-supply wells in Arkansas, Louisiana, and Texas that were located as close as 360 feet to unconventional oil and gas wells.
Methane was detected in 91% of the wells and, of those, 90% had methane concentrations lower than the threshold of 10 mg/L. The Department of the Interior Office of Surface Mining, Reclamation, and Enforcement
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USGS Study Finds Unconventional Oil and Gas Production Not Currently Affecting Drinking Water Quality (Continued)
proposed this threshold for the purposes of protection from explosive risk. Most of the methane detected in groundwater was from naturally occurring microbial sources at shallow depths rather than deep shale gas.
Although benzene was detected in 8% of the wells sampled, concentrations were low––the highest concentration was nearly 40 times lower than the federal standard for benzene in drinking water (5μg/L). Benzene was detected about 1.5 to 8 times more frequently in the study area in groundwater than in national data sets of benzene in groundwater.
Groundwater in the Louisiana and Texas study areas typically entered the aquifers several 1000 years ago. Nearly all the benzene detected in those areas occurred in old groundwater, indicating it was from subsurface sources such as natural hydrocarbon migration or leaking oil and gas wells. In Arkansas, groundwater was much younger—typically less than 40 years old. Benzene was detected in one sample of young groundwater in Arkansas that could be associated with a surface release associated with unconventional oil and gas production activities.
This is the first study of these areas to systematically determine the presence of benzene and methane in drinking water wells near unconventional oil and gas production areas in relation to the age of the groundwater. Methane and benzene, produced by many unconventional oil and gas wells, have various human health implications when present in high concentrations in drinking water.
The USGS has pioneered the ability to determine the age of groundwater.
“Understanding the occurrence of methane and benzene in groundwater in the context of groundwater age is useful because it allows us to assess whether the hydrocarbons were from surface or subsurface sources. The ages indicate groundwater moves relatively slowly in these aquifers. Decades or longer may be needed to fully assess the effects of unconventional oil and gas production activities on the quality of groundwater used for drinking water,” said Peter McMahon, USGS hydrologist and study lead.
To access the study, visit www.usgs.gov/news/unconventional-oil-and-gas-production-not-currently-affecting-drinking-water-quality.
New USGS Assessment Provides Fresh Insights into Nation’s Brackish Groundwater Inventory
A new nationwide assessment by the U.S. Geological Survey suggests the nation’s brackish groundwater could help stretch limited freshwater supplies.
The study, the first of its kind in more than 50 years, found the amount of brackish groundwater underlying the country is more than 800 times the amount currently used each year. With issues like drought, groundwater depletion, dwindling fresh water supplies, and demand for groundwater expected to continue to rise, understanding brackish groundwater supplies can help determine whether they can supplement or replace taxed fresh water sources in water-stressed areas.
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New USGS Assessment Provides Fresh Insights into Nation’s Brackish Groundwater Inventory (Continued)
“This assessment lays the foundation for building a deeper understanding of brackish groundwater resources and how they might be used to better ensure our water security,” said Jennifer Stanton, a USGS hydrologist and lead author of this assessment.
In general, brackish groundwater is groundwater that has a dissolved solids content greater than fresh water but less than sea water. It is defined for this assessment as having a dissolved-solids concentration ranging from 1000 to 10,000 mg/L.
This new assessment was authorized by the 2009 SECURE Water Act and builds on a 1965 study, which for more than five decades has served as the primary source of information on the national distribution of brackish groundwater. By incorporating data from more than 380,000 sites, compared to about 1000 for the 1965 study, the 2017 assessment provides more comprehensive, nationwide data on the quantity and quality of brackish groundwater across the country. This includes information like chemical composition of the water and well yields, which are necessary for understanding the potential—at the national and regional scales—for expanding brackish groundwater development and for informing decision-makers and policymakers.
All water naturally contains dissolved solids that, if present in sufficient concentration, can make the water brackish, or slightly salty. Sources of these dissolved solids can include ancient sea water, coastal sea water, dissolution of naturally occurring minerals, leaching from saline soils, road salt, brine from oil and gas wells, or other human activities.
The assessment provides data for states and other public agencies interested in using brackish groundwater. It also supports the efforts of the U.S. Bureau of Reclamation to promote sustainable water treatment for brackish aquifers.
“The use of brackish groundwater to augment water supply in the West has been analyzed as a potential adaptation strategy in a number of studies under Reclamation’s Basin Studies Program,” said Katharine Dahm, an engineer with the U.S. Bureau of Reclamation.
Advances in desalination technology and increases in demand for uses that do not need high-quality water—like mining, oil and gas development, and thermoelectric power generation—have led states like Texas and California to turn to brackish groundwater as an alternative to fresh water.
To read more, visit www.usgs.gov/news/usgs-assessment-brackish-water-could-help-nation-stretch-limited-freshwater-supplies.
The USGS also published an interactive online map of water quality trends between 1972 and 2012. The data cover nutrients, pesticides, salinity, sediment, and other parameters. To view the data, visit https://nawqatrends.wim.usgs.gov/swtrends.
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The Case for Flux-Based Remedial Performance Monitoring Programs
It is generally accepted that the spatial distribution of contaminant mass flux (the rate of mass flow per unit aquifer cross-sectional area) at even the geologically simplest of sites, is highly variable and that the majority of contaminant mass transport occurs in a small fraction of the aquifer that is associated with the highest conductive zone(s). This mass flux is a measure of plume strength and associated risk to downgradient receptors (Einarson and Mackay 2001; Payne et al. 2008; Suthersan et al. 2010; Hadley and Newell 2012). Furthermore, it is increasingly recognized that the complete restoration of some source and/or high-concentration zones to drinking water quality standards may be impractical and very costly due to a variety of rate-limiting mechanisms including dissolution, desorption, and diffusion from mass stored in lower permeability zones. Accordingly, it is becoming a best practice to incorporate high-resolution characterization tools into flexible and adaptive investigations to map contaminant mass flux supporting the design of flux-focused remediation systems.
In response to the evolving mass flux prioritization, some regulatory programs are beginning to support remedial performance objectives that are targeted primarily at reducing contaminant concentrations in the highest permeable/flux zones to achieve risk-based goals. These risk-based remedial goals conceptually acknowledge the primary importance of reducing the mass discharge, defined as the integrated mass flux, and recognize that groundwater quality standards may not need to be universally achieved at some sites with a significant amount of mass in low-permeability (i.e., low mass flux) zone(s). In some cases, the concept of mass flux is implicit, for example, guidance on the use of passive diffusion bags (PDBs) states that the hydraulic conductivity should be >10−5 cm/s for PDB deployment (USEPA 2013). However, while the concept of using contaminant mass flux as a performance goal is generally accepted, its current practical implementation is not widespread. At many sites it is challenging to measure absolute mass discharge/flux values (ITRC 2010). More importantly, however, it is very difficult to establish quantitative flux reduction targets that can be incorporated into current regulatory frameworks.
Figure 1. Contaminant concentrations in monitoring wells during the remediation of a source zone. The estimated pump and treat mass recovery (volume of water recovered multiplied by concentration; which can be seen as proportional to mass discharge) declined approximately four orders of magnitude, however, concentrations at three wells declined two to four orders of magnitude (flux zone), while concentrations at a well screened in low conductivity (K) zone declined only about half an order of magnitude.
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The Case for Flux-Based Remedial Performance Monitoring Programs (Continued)
Despite the continuing development of many new flux-focused investigation technologies, the assessment of remediation effectiveness continues to rely primarily on reducing contaminant concentrations at permanent monitoring wells with typical screen lengths of up to 10 feet (or longer if older wells). Unfortunately, most monitoring programs are not designed to measure changes in mass flux, but are primarily intended to monitor changes in the plume's spatial footprint. Furthermore, they often focus on wells with high concentrations without specific consideration to whether these wells are the best indicators of significant reductions in mass flux. While orders of magnitude differences exist in mass flux across most sites, data from monitoring wells screened in higher hydraulic conductivity media or highly fractured rock are inappropriately weighted equal to those screened within low hydraulic conductivity zones. Figure 1 provides an example case where multiple orders of magnitude reduction in mass recovery from groundwater extraction was realized without corresponding concentration reductions at monitoring wells, particularly those screened in low-permeability (i.e., storage) zones.
Preferably, performance monitoring wells should more appropriately be defined using flux-based criteria: simply put, at sites where the most appropriate remedial goals are flux-focused, wells screened across very low-permeability zones should be eliminated from remedial performance monitoring programs because they produce unrepresentative and potentially misleading data. Fortunately, at most recently-investigated sites, most monitoring wells already target higher flux zones. However, for legacy sites, where the monitoring network consists of a mix of monitoring wells screened within both high and low hydraulic conductivity zones, we suggest opening a discussion between regulators and stakeholders to shift the focus of remedial performance monitoring to wells screened within zones that contribute most to the contaminant mass discharge and potential risk. This could include weighting both contaminant concentrations and Darcy velocity (product of hydraulic conductivity and hydraulic gradient) of the individual monitoring wells. This assessment could include a
Figure 2. Tracer washout data from a series of simple single-well tracer tests that measure local groundwater flux. These results quantitatively show that groundwater flux values in wells screened in unweathered rock were more than two orders of magnitude lower than wells screened in partially weathered rock (PWR) wells. These results provided the basis for an approved performance monitoring program that focused only on the PWR wells and excluded bedrock monitoring wells.
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The Case for Flux-Based Remedial Performance Monitoring Programs (Continued)
statistical approach, but as a rule of thumb, higher weight would be placed on zones with hydraulic conductivity of >10−2 cm/s for unconsolidated aquifers and >10−4 cm/s for fractured rock. Hydraulic tests or single-well tracer tests (Figure 2) can provide compelling quantitative data to support this type of assessment.
Monitoring programs intended to evaluate remediation success and risk reduction need to align with our current understanding of transport, which will require current programs for many sites to undergo significant modification. Only wells that monitor significant mass flux zones should be included; wells that monitor very low-permeability zones should not be included, even if current contaminant concentrations are relatively high. In some cases, these wells could be abandoned or used for purposes not directly related to the remedial performance monitoring program.
To read more, visit http://onlinelibrary.wiley.com/doi/10.1111/gwmr.12225/full
Geologists Spot a Pattern, Predict Big Quakes in 2018. Whenever The Earth's Rotation Slows, As It Is Now, An Increase In Major Quakes
Follows Two geologists may have spotted a surprisingly simple correlation that can help predict earthquakes—and if they're correct, the Earth is on track for an uptick in major quakes next year. The pair pored over a century's worth of a data on earthquakes and detected a pattern: When the Earth's rotation slows, as it does periodically, the slowdown is followed by an increase in quakes with a magnitude of 7 or greater, reports the Guardian. Their research, published in Geophysical Research Letters, has been well-received in the field, and it will be put to the test soon. The rotational slowdowns typically happen over five years, and the last began four years ago. Meaning, we can expect to see two to five more major earthquakes than normal in 2018, or 17 to 20, reports Science. "The Earth offers us a five-years' heads up on future earthquakes, which is remarkable," says Roger Bilham of the University of Colorado, who detected the correlation with Rebecca Bendick of the University of Montana. Exactly where the quakes will take place is fuzzier, but typically the increase shows up in regions along the Equator. The researchers aren't sure how to explain all this, but one theory is that it involves nearly imperceptible changes in the flow of molten iron in the Earth's core. That might be enough to slow down the Earth's spin a millisecond or two, a difference that can be measured by atomic clocks, and perhaps result in the release of vast amounts of energy underground. The cycle seems to take place about every three decades, writes geologist Trevor Nace at Forbes. (LA residents won't like this San Andreas prediction.) To read more, visit http://www.newser.com/story/251820/geologists-spot-a-pattern-predict-big-quakes-in-2018.html
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Fernbank Events & Activities
HollyJollyFilmFestSaturday, November 25, 2017 Join us for a day of holiday-themed fun including special screenings of How the Grinch Stole Christmas.
Learn more
TreetopTalesSaturday, November 25, 2017 Bring your little explorers for a special story and activity with a Fernbank educator. Learn more
NoonYear’sEveSunday, December 31, 2017 Tickets are now on sale for this annual family event. Learn more
FernbankAfterDarkFriday, December 8, 2017 Enjoy an evening of holiday-infused science activities, live music and more.
Learn more
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Wildwoods and Fernbank Forest WildWoods features 10 acres of lush woodlands,
highlighted by hands‐on exhibits for all ages, tree
pods suspended in the canopy, a nature gallery,
immersive adventures, and meandering trails
emphasizing dramatic slopes and stunning
views. This interpretive nature experience serves as
the new entrance into Fernbank Forest.
Learn more
Wild Huts and Hollows On view September 9 – February, 2018 Explore a variety of woven sculptures by mixed media artist, J.D. Koth. This special exhibit will feature archways and huts of various sizes, all constructed using locally-harvested plant material and designed to spark the imagination and curiosity of both kids and adults. Visitors will be invited to explore many of the woven sculptures inside and out, offering guest unique photos opps.
Learn more
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Now showing in the Fernbank IMAX movie theater:
Gladiators: Heroes of the Colosseum September 29 – January 7, 2018 From the seats of the world’s most iconic stage, Fernbank invites visitors to discover the story behind one of Rome’s most celebrated traditions in this stunning new special exhibit. Building on the larger-than-life legends of gladiators, the exhibit explores the world these men inhabited, from the regimen of training, discipline and constant peril to the fame, wealth and freedom that greeted the very best gladiators. The exhibit unfolds on two paths, revealing two protagonists interwoven by destiny: the gladiators themselves, and the colossal, complex stage where their fate was determined—the Colosseum. The story is told through original artifacts, modern replicas, interactive technology, and immersive environments. In celebration of the Museum’s 25th anniversary, Fernbank will plunge visitors into the very heart of ancient Rome.
Incredible Predators 3D September 30 – February 8, 2018 Life at the top of the food chain isn’t easy. Even the most ferocious predators must overcome great odds to feed their families and survive. Incredible Predators 3D takes viewers on a globe-spanning journey to meet unique creatures, from the minuscule mantis to the massive blue whale. Experience the thrill of the chase, the great escapes, and the remarkable strategies and determination of nature’s predators in Fernbank’s state-of-the-art Giant Screen Theater.
Fernbank Museum of Natural History
(All programs require reservations, including free programs)
AGS November 2017 Page 17
AGS Committees
AGS Publications: Open
Career Networking/Advertising: Todd Roach
Phone (770) 242‐9040, Fax (770) 242‐8388
Continuing Education: Open
Fernbank Liaison: Kaden Borseth
Phone (404) 929‐6342
Field Trips: Open
Georgia PG Registration: Ken Simonton
Phone: 404‐825‐3439
[email protected] Ginny Mauldin‐Kenney,
ginny.mauldin@gmailcom
Teacher Grants: Bill Waggener
Phone (404)354‐8752
Hospitality: John Salvino, P.G.
Membership: Burton Dixon
Social Media Coordinator: Carina O’Bara
Newsletter Editor: James Ferreira
Phone (508) 878‐0980
Web Master: Ken Simonton
[email protected] www.atlantageologicalsociety.org
AGS 2017/2018 Meeting Dates
Listed below are the planned meeting
dates for 2017/2018. Please mark your
calendar and make plans to attend.
2017/2018 Meeting Schedule November 28 Speaker Dr. Stephen
Henderson from Emory University
December 26 No Meeting
January 30
February 27
March 27
April 24
PG Study Group meetings Contact Ken Simonton for the details.
December 18
January 27
February 24
March 24
April 28
AGS Officers
President: Ben Bentkowski
Phone (770) 296‐2529
Vice‐President: Steven Stokowski
Secretary: Rob White
Phone (770) 891‐0519
Treasurer: John Salvino, P.G.
Phone: 678‐237‐7329
Past President
Shannon Star George
Page 18 AGS November 2017
ATLANTA GEOLOGICAL SOCIETY
www.atlantageologicalsociety.org ANNUAL MEMBERSHIP FORM
Please print the required details and check the appropriate membership box. DATE:_____________________________________________ NAME:____________________________________________
ORGANIZATION:____________________________________________________________
TELEPHONE (1): TELEPHONE (2): EMAIL (1): EMAIL (2):
STUDENT $10 PROFESSIONAL MEMBERSHIP $25 CORPORATE MEMBERSHIP $100 (Includes 4 professional members, please list names and emails below) NAME: EMAIL:
NAME: EMAIL:
NAME: EMAIL:
NAME: EMAIL:
For further details, contact the AGS Treasurer: John Salvino [email protected]
Please make checks payable to the “Atlanta Geological Society” and bring them to the next meeting or remit with the completed form to:
Atlanta Geological Society, Attn: John Salvino 3073 Lexington Avenue
Woodstock, Georgia 30189
To pay electronically; click
https://squareup.com/store/atlanta‐geological‐society CASH CHECK (CHECK NUMBER:___________)