Atlanta Geological Society Newsletter

ODDS AND ENDS Dear AGS members, March Meeting It has been said that lifelong learning is good for your health, your wallet, and your social Join us Tuesday, March 27, 2018 at the life. I bet not a week goes by that I don’t get a Fernbank Museum of Natural History, 760 reminder of the importance of lifelong learning. Clifton Road NE, Atlanta GA. The Just last Tuesday I was on a dolphin cruise with meeting/dinner starts at 6:30 pm and the my land-lubber grandchildren explaining about meeting starts approximately 7 p.m. relationship between the fetch of the wind and wave heights and back bay ecology and then I This month’s presentation is: “Flooding in learned that dolphins sometimes swim in their Georgia – Why Maps May Not Predict backs to trap the little fish between them and The Future or The Past” presented by the water’s surface. And I saw it in person; Mr. Alan Giles. Please find more even better. I’m on this big project at work that information about Abigail’s bio on Page 2 continually forces me to really know my of the newsletter. technical stuff as we get closer to making a decision. Sort of a self -perpetuating cycle but I Please come out, enjoy a bite to eat, the can’t tell if you learn more so you do more and camaraderie, an interesting presentation and then you learn more OR you do more, so you perhaps some discussion on the importance learn more, so you can then do more. Either of accurate mineral characterization. Also, way, you come out the better for it. the differences that can exist between I see this play out at the AGS as well. We all mineralogical, industrial and regulatory gather to learn about the topic of the month. definitions for minerals. You never know when those specialized tidbits will come in handy. You might meet someone that could help find your next job or get over a www.atlantageologicalsociety.org rough patch in the one you have. Just look at Howard Cramer, still pushing himself to learn facebook.com/Atlanta-Geological-Society even more. We all could learn that life lesson.

Hope to see you Tuesday! Ben Bentkowski, President

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This Month’s Atlanta Geological Society Speaker

Flooding in Georgia – Why Maps May Not Predict The Future or The Past

Mr. Giles’s Résumé Biography for Alan J. Giles, CFM & Information Geologist with the Georgia Department of Natural Resources, Environmental Protection Division, Floodplain Management Unit: Born and raised in the District of Columbia. He was the first in his neighborhood to:

1) Be a Red Cross Certified Water Safety Instructor

2) Graduate from college as a geology major (Boston University)

3) Explore the ground with sound as an exploration geophysicist (Seismograph Service Corporation & Getty Oil)

4) Investigate potentially hazardous waste sites, hazardous waste generators, and industrial solid waste facilities (Land Protection Branch* and Hazardous Waste Management Branch*)

5) Volunteer over 1,000 hours as a docent with a major science museum (Fernbank Museum of Natural History)

6) Serve on the technical staff of a state geologic survey (Georgia Geologic Survey*)

7) Become a Certified Floodplain Manager (Association of State Floodplain Managers - ASFPM)

8) Serve on a national board of a technical organization (ASFPM)

*These organizations were historically part of the Georgia DNR/EPD. In his current role with Floodplain Management, he reviews flood risks for state-funded educational sites/facilities, provides technical assistance concerning floodplain management issues, and participates in outreach activities to promote better flood risk awareness and as an advocate of recognizing, protecting, and restoring the natural and beneficial functions of floodplains. Professional affiliations include ASFPM, the Georgia Association of Floodplain Management, and of course the Atlanta Geological Society.

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Update: Lopsided Ice on The Moon Points to Past Shift in Poles

Scientists announced that the spin axis of the moon is about 6° different than it was billions of years ago, based on evidence of off-kilter polar ice deposits. Science first reported on this story last year when the scientists presented the research at the Lunar and Planetary Science Conference in The Woodlands, Texas.

THE WOODLANDS, TEXAS—What little ice remains on Mercury and Mars is mostly confined to the planets’ poles, as one would expect, because the sun shines the least in those regions. Not so on the moon. Much of the moon’s ice, which lurks beneath the surface, is found in an area 5.5° away from the north pole and in a matching region 5.5° from the south pole, scientists announced here this week at the Lunar and Planetary Science Conference. The data suggest that in the past, the moon’s axis of rotation—and hence its poles—shifted.

“It turns out these enhanced concentrations are exactly opposite each other—they’re antipodal,” says Matthew Siegler, a planetary scientist at the Planetary Science Institute who is based in Dallas, Texas. “The easiest explanation is: There used to be poles there.” Siegler and his colleagues have suggested a cause for the “polar wander”: a 3.5-billion-year-old hot spot beneath the moon’s surface. If the story holds up, it means the moon's water is nearly as ancient as the orb itself.

The researchers relied on data from NASA’s Lunar Prospector mission, which orbited the moon from 1998 to 1999. One of the spacecraft’s instruments measured neutrons emitted from the surface. Slower, less energetic ones indicate the amount of hydrogen lurking within a meter of the surface, and on the moon, hydrogen is a proxy for water. Although scientists had noticed before that the water was not centered at the current poles, no one had noticed this precise off-axis, antipodal relationship. “Everyone is basically kicking themselves and saying, ‘Why didn’t I notice this?’” Siegler says.

An off-axis abundance of water at the moon’s north pole (left) is matched symmetrically at the south pole (right).

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Update: Lopsided Ice on The Moon Points to Past Shift in Poles (Continued)

He and his colleagues assumed that when the ice was deposited, it was centered on the poles. But what kind of event could have moved the poles by 5.5°? Known asteroid impacts were too small or in the wrong location to do the job. Instead, the team hypothesizes that a 3.5-billion-year-old hot spot could have nudged the poles to their present-day position. Pouring out enormous amounts of lava, that hot spot created Oceanus Procellarum, the vast dark spot on the near side of the moon. The Procellarum region is known to have high concentrations of radioactive elements that would have been hot in ancient times. The research team theorizes that this heat would have created a less dense lens in the moon’s mantle that would have caused the axis to wobble into today’s position.

If that idea is correct, then it implies that the moon’s water is mostly ancient—contrary to scientists who have argued that water was delivered more recently by asteroid impacts or even produced by a hail of protons known as the solar wind. “That ice might be primordial from the beginning of the moon,” Siegler says.

“It’s a terrific idea,” says Oded Aharonson, a planetary scientist at the Weizmann Institute of Science in Rehovot, Israel. But Aharonson isn’t sure the ice could have persisted for so long. At other times in its ancient past, the moon’s poles are thought to have wandered far enough to bring polar regions near the sun-drenched equator. Moreover, ice could be destroyed by large asteroid impacts. For the ice to survive, the 5.5° tilting event would need to occur after those cataclysms, he says. “It’s really critical not to do this [tilting] too early in lunar history,” he says.

But the research team says there are ways for the ice to persist through the ages. Some of the water may be locked up as hydrated minerals in rocks. And some of it may be protected by an insulating layer of regolith, says Richard Miller, a planetary scientist at the University of Alabama, Huntsville, and a collaborator on the research. “If it gets buried and moves to depth, some fraction can survive for a long period of time.”

Read more about this article at: http://www.sciencemag.org/news/2016/03/update-lopsided-ice-moon-points-past-shift-poles

Want to Discover Truly Alien Life? Pack A Genome Sequencer

THE WOODLANDS, TEXAS—What if aliens aren’t like us? For a long time, that’s been a confounding problem in the search for life beyond Earth: If alien life looks nothing like it does on our planet, if it abjures DNA and RNA for building blocks utterly strange, how could robotic explorers even know that they’ve discovered it?

With scientists eyeing the potentially habitable waters of Jupiter’s moon Europa and Saturn’s moon Enceladus, this question has only grown more pressing. It’s fine to think any life on Mars could have shared ancestry with Earth—the planets are close and have shared a lot of grist over billions of years—but DNA-based life at Saturn? That would be a stretch.

Still, the hunt for nonterran life could be accomplished with a tool familiar in any biology lab, scientists suggested here yesterday at the Lunar and Planetary Science Conference and in a paper in press at Astrobiology. If you want to have the broadest possible search for life, both terran and nonterran, they say, pack a genome sequencer. “You could have a completely different biochemistry,” says Sarah Stewart Johnson, an astrobiologist at Georgetown University in Washington, D.C., who led the work. “But you could still see a signal.” AGS February 2018 Page 9

Want to Discover Truly Alien Life? Pack A Genome Sequencer (Continued)

The technique as proposed would work because nucleic acids like DNA are promiscuous. Take a strand 30 to 80 nucleotides long and it will naturally form secondary and tertiary structures that will bind with a host of materials and shapes: biologicals like peptides and proteins, sure, but also to organic molecules, minerals, and even metals.

Johnson’s team borrowed a technique from cancer biology, called the systematic evolution of ligands by exponential enrichment (SELEX), which creates a huge library of random, short chains of nucleotides, called aptamers, and then incubates them with a target of choice, such a specific breast cancer cell. SELEX is typically repeated multiple times, with scientists filtering out the aptamers that are not specific to their target.

“The idea here would be to flip that around,” Johnson says. Their sensor would expose samples to all those random aptamers, garnering information from each hit. “Analyze the whole binding pattern, anything that binds,” she says. These patterns could then be amplified and sequenced, revealing a pattern of chemical complexity that Johnson calls a fingerprint.

Such a fingerprint would not be as clear as catching DNA in a sequencer. But if a sample is exposed to such an aptamer library, a complex molecule is going to bind with a lot more sequences than a simple one. And complexity, especially if captured in a very small sample, is likely a hallmark of life. "It might not be as definitive as your DNA sequencer, but it could be, if not a biosignature, a really strong bioprint,”Johnson says.

This is not the only approach to agnostic life detection, as the nascent field is called, most of which require trading definitiveness for inclusivity. Johnson has worked with other scientists who have shown how a mass spectrometer, a tool common on NASA robotic missions right now, could be twinned with algorithms designed to evaluate a molecule’s complexity, not just its weight. Other techniques could gauge signs of mobility or energy use to flag nonterran life, Johnson adds, though those are not as technologically ready.

In recent years, genome sequencers have dramatically shrunk in size; Oxford Nanopore’s MinION, for example, weighs only 85 grams and fits in your hand. Although no NASA mission currently has plans to take a sequencer into space, the agency is supporting several efforts to get the technology ready for exploration.

Johnson’s proposal seems innovative and could complement other efforts at life detection, says Christopher Carr, an astrobiologist at the Massachusetts Institute of Technology in Cambridge who is not involved in the work. Carr is leading one of the NASA sequencing efforts, and Johnson’s technique could increase such a tool’s usefulness. “It will have a high likelihood to produce data for any given sample, whether or not it contains life,” he says. But the approach also carries the risk of providing confusing data, especially from unknown materials. Careful preparation and instruments that provide context for the sample could help overcome such hurdles, he adds.

Johnson, for one, is eager to get going with the hunt for life. She wants sequencers everywhere—not just on the outer planets, but also for samples of the Mars subsurface or Saturn’s moon Titan, dipped in frozen methane. “I want to go to Titan where everything is crazy and different,” she says. “I just want to go. I want to go everywhere.”

Read more about this article at: http://www.sciencemag.org/news/2018/03/want

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A Dusting of Salt Could Cool the Planet

THE WOODLANDS, TEXAS—A last-ditch remedy for a climate disaster might be waiting in your kitchen. If efforts to control greenhouse gases fail, finely powdered salt spread through the upper troposphere could hold off the sun's rays and cool the planet, researchers reported here today at the Lunar and Planetary Science Conference. The approach could be more benign than other schemes for putting a temporary hold on climate change.

For several decades, scientists have suggested ways to “geoengineer” the climate. Several proposals call for injecting microscopic particles, called aerosols, into the stratosphere, the quiet region of the atmosphere above the troposphere about 18 kilometers up from the equator. There they reflect sunlight back into space, mimicking the influence of large volcanic eruptions that have temporarily cooled the planet in the past.

Such proposals often involve sulfates, particles that form in the stratosphere from sulfur dioxide ejected by volcanoes, or other molecules with high reflectivity, such as diamond dust or alumina (aluminum oxide). But all these approaches have drawbacks, says Robert Nelson, a senior scientist at the Planetary Science Institute who is based in Pasadena, California. Sulfur dioxide, for example, could eat away at the ozone layer or cause acid rain.

Alumina could be even worse, Nelson says. Although it is extremely reflective, it could embed in the lungs if inhaled and cause chronic disease similar to silicosis. “I was raised in Pittsburgh, [Pennsylvania,] and I remember as a child seeing black lung victims struggling to get down the street.” Still, given the limited amount of alumina that could be required, it’s far from certain such a health risk would be a genuine concern.

So Nelson continued to look for other reflective compounds that might be less hazardous to human health. In 2015, he was studying evaporated salts on the surface of other solar system bodies such as the dwarf planet Ceres. He soon realized that simple table salt is more reflective than alumina, while also harmless to humans. Just as important, Nelson believes that salt, when ground into small enough particles of the right shape and dispersed randomly, would not block outgoing infrared heat released by Earth, adding to its cooling effect.

Scientists have proposed injecting salt into the upper troposphere, above the clouds, as a form of geoengineering.

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A Dusting of Salt Could Cool the Planet (Continued)

Nelson is not the first to consider salt, says Matthew Watson, a volcanologist at the University of Bristol in the United Kingdom. Watson led a geoengineering experiment, called the Stratospheric Particle Injection for Climate Engineering project, that was canceled in 2012. His group briefly considered salt for stratospheric injection, he says, but problems popped up.

First, there's a lot of chlorine in salt, and chlorine can contribute to destroying ozone. That alone could be enough to kill salt as a candidate, Watson says. Few would likely welcome injecting a particle that could reopen the ozone hole. "[This] could be a big problem," agrees David Keith, an energy and climate scientist focused on geoengineering at Harvard University. Salt is also highly attracted to water, and water is scant enough in the stratosphere that injecting even limited amounts of salt could potentially alter, for example, the formation of the realm’s wispy clouds, to unknown effects.

Nelson hopes these concerns could be addressed by injecting salt in the high troposphere, above the clouds but below the stratosphere. He also plans to look more closely at salt's properties; if he can resolve some of these questions, he'd like to see a test of the particles above a region forecasted to experience life-threatening extreme temperatures. This would test the science while potentially benefiting society in the short term, he says. Such a research effort could only come after thorough engagement with the public, Nelson adds.

But like nearly all scientists interested in geoengineering, Nelson stresses that the strategy is no substitute for action to curb carbon emissions. No type of solar radiation management, for example, would prevent rising carbon dioxide from acidifying the oceans. This research should only be done so the world can potentially buy itself some time, Nelson says. “This would be a palliative, not a [long-term] solution.”

Read more about this article at: http://www.sciencemag.org/news/2018/03/dusting-salt-could-cool-planet

In 1986, Scientists Found a Fuel-Producing Bacterium at The Bottom of a Swiss Lake. Now, They Know How It Works

Thirty-two years ago, microbiologists in Switzerland stumbled on a mystery deep in the muck of Lake Zurich: a bacterium that naturally produced a component of gasoline called toluene. Now, researchers have discovered how some bacteria manage to make the toxic hydrocarbon. Why they do remains a puzzle, however.

“This is a really nice piece of science,” says Alfred Spormann, a chemical engineer at Stanford University in Palo Alto, California, who was not involved in the work. “I think it’s a terrific example of using metagenomics and biochemistry to learn about organisms that are difficult to study.”

The Lake Zurich discovery fingered a bacterium, Tolumonas auensis, as the toluenemaker, and raised the prospect of culturing it to produce the hydrocarbon as a fuel. T. auensis isn’t the only bacterium that makes hydrocarbons, but its byproduct is odd: Toluene is packed with energy, meaning an organism must expend a lot of energy to produce it. It’s also toxic. But T. auensis is particularly hard to culture in Petri dishes and study with the normal tools of molecular biology. The trail ran cold.

A few years ago, Harry Beller, an environmental microbiologist at the Joint BioEnergy Institute (JBEI) in Emeryville, California, decided to reopen the case. His team first tried recreating the 1986 experiment, in which

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In 1986, Scientists Found a Fuel-Producing Bacterium at The Bottom of a Swiss Lake. Now, They Know How It Works (Continued) researchers got T. auensis to make toluene. But after multiple attempts, Beller’s team struck out. So, he called Friedrich Jüttner, the group leader from the original Nature paper, to ask for advice. Jüttner, Beller says, told him not to worry about T. auensis and suggested that he could probably find a similar organism doing the same thing in sediments from any nearby lake.

So Beller and his colleagues drove 13 kilometers from JBEI to Tilden Park in nearby Berkeley, where they took samples from a small reservoir called Jewel Lake. Back at the lab, they found that Jüttner’s words were prescient: The lake sample registered traces of toluene. They found similar traces in samples from a nearby sewage treatment plant.

Beller and his colleagues then divided their mud and sewage samples into successive fractions, winnowing out those that showed no signs of the hydrocarbon. They ran the “keepers” through genomic scans, creating a library of 600 likely candidate genes from the two samples. Previous analyses had suggested that the genes responsible for making toluene were likely glycyl radical enzymes (GREs), a small family of proteins that carry out other complex chemical reactions. They always come paired with an activating enzyme. So Beller’s team looked for just such a cluster in data from the sewage sample, and they found the GRE phenylacetate decarboxylase (Phd B) and its activator, Phd A. “We looked for it in the lake culture and found it there, too,” Beller says.

To confirm that these were the toluene-producing proteins, Beller’s team transplanted the genes into easily cultured Escherichia coli bacteria, which expressed the proteins. The researchers purified the proteins and added them to a vial containing phenylacetic acid, the normal starting material for Phd B. But in this case the phenylacetic acid was made using carbon-13, a rare isotope of carbon that enabled Beller’s team to trace the fate of the compound as it reacted. The researchers found that the enzymes produced C-13–labeled toluene, they report this week in Nature Chemical Biology. The result confirms the enzymes are the ones at work in the muck—and presumably in T. auensis.

So why do microbes produce toluene? They might use the toxic compound to ward off competing bacteria, Beller says. A more likely explanation, though, is that the production of toluene creates energy for the single- celled microbe. The chemical currency of cellular metabolism, adenosine triphosphate is produced only after protons are pumped out of the cell and into its surroundings, setting up a pH gradient across the cell membrane. Because the production of toluene effectively pumps protons into the cell, Beller suspects the same energy- producing system might also be able to run in reverse.

Whatever the explanation, Beller says he and his colleagues are now working to engineer other easily cultured organisms to make toluene. Eventually that could lead to industrial microbes that synthesize one key component of gasoline. But because toluene derived from oil is cheap, even perfectly functioning bugs may not find much of a market. Solving a mystery may be their work’s biggest payoff.

Read more about this article at: http://www.sciencemag.org/news/2018/03/1986-scientists-found-fuel-producing-bacteria-bottom- swiss-lake-now-they-know-how-it

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What Made Triceratops So Horny?

Horn-faced dinosaurs like Triceratops had elaborate frills and spurs that adorned their skulls and grew more elaborate—and diverse—through the eons. Later species, such as Chasmosaurus belli (above), sported frills that were up to a meter long. Paleontologists have floated several ideas about what spurred the evolution of such elaborate headgear. Recently, some have suggested it might have been a way to communicate with other dinosaurs, helping them recognize members of their own species.

To test whether species recognition was the driving force behind the adornments, scientists examined whether horn-faced species that shared territory also had more distinct ornaments. They compared 350 different characteristics in 1035 different species pairs. Thirty-eight of the pairs existed at the same time in the same region, and 63 more lived at the same time on the same continent, though their fossils have not ever been found together in the same area. The researchers found no evidence that any of the pairs were more distinct from each other than pairs that came from different eras or completely different regions.

That means it’s unlikely that the horns evolved to help animals recognize their own species, the researchers conclude in a paper published today in the Proceedings of the Royal Society B. It’s more plausible, they say, that the horny bling was driven by socio-sexual signaling: Frills and horns were advertisements of health and strength, and bigger, fancier ones helped their owner attract a mate.

Read more about this article at: http://www.sciencemag.org/news/2018/03/what-made-triceratops-so-horny

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Nodosaur Dinosaur “Mummy” Unveiled With Skin and Guts Intact

“We don't just have a skeleton," said one of the nodosaur researchers involved. "We have a dinosaur as it would have been."

You can’t even see its bones, yet scientists are hailing it as perhaps the best-preserved dinosaur specimen ever unearthed. That’s because, 110 million years later, those bones remain covered by the creature’s intact skin and armor.

Indeed, the Royal Tyrrell Museum of Palaeontology in Alberta, Canada recently unveiled a dinosaur so well- preserved that many have taken to calling it not a fossil, but an honest-to-goodness “dinosaur mummy.”

With the creature’s skin, armor, and even some of its guts intact, researchers are astounded at its nearly unprecedented level of preservation. “We don’t just have a skeleton,” Caleb Brown, a researcher at the Royal Tyrrell Museum, told National Geographic. “We have a dinosaur as it would have been.”

When this dinosaur — a member of a new species named nodosaur — was alive, it was an enormous four-legged herbivore protected by a spiky, plated armor and weighing in at approximately 3,000 pounds.

Today, the mummified nodosaur is so intact that it still weighs 2,500 pounds.

How the dinosaur mummy could remain so intact is still something of a mystery, although as CNN says, researchers suggest that the creature “may have been swept away by a flooded river and carried out to sea, where it eventually sank. Over millions of years on the ocean floor, minerals took the place of the dinosaur’s armor and skin, preserving it in the lifelike form now on display.”

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Nodosaur Dinosaur “Mummy” Unveiled With Skin and Guts Intact (Continued)

Although the nodosaur dinosaur mummy was so well-preserved, getting it into its current display form was still an arduous undertaking. The creature was, in fact, first discovered in 2011 when a crude oil mine worker accidentally discovered the specimen while on the job.

Since that lucky moment, it has taken researchers 7,000 hours over the course of the last six years to both test the remains and prepare them for display at the Royal Tyrrell Museum, where visitors now have the chance to see the closest thing to a real-life dinosaur that the world has likely ever seen.

After this look at the nodosaur, the mummified dinosaur, read up on the recently discovered dinosaur footprint that’s the largest ever found. Then, check out the first-ever dinosaur brain ever found by scientists.

Read more about this article at: http://allthatsinteresting.com/nodosaur‐dinosaur‐mummy

The Hydrologic Cycle The oldest and most significant problem in hydrogeology is the nature of the hydrologic cycle (Deming 2005, 2014). Because the rivers never ran dry and the sea never overflowed, it was understood that there must be some circulation of seawater back to the land. But an understanding of how this took place was problematical for thousands of years. Thoughts on the nature of the hydrologic cycle date at least to the time of the ancient Greeks. Aristotle (384 to 322 BC) had some insight that the process must be cyclic. In Meteorologica he noted that “we get a circular process that follows the course of the Sun. For according as the Sun moves to this side or that, the moisture rises or falls. We must think of it as a river flowing up and down in a circle and made up partly of air, partly of water” (Aristotle 1923, 47a). Aristotle also exhibited some conception of rocks and soil as porous media when he wrote that “mountains and high ground, suspended over the country like a saturated sponge, make the water ooze out and trickle together in minute quantities but in many places” (Aristotle 1923, 350a). But he rejected precipitation and infiltration as the source of stream recharge. To the Greeks, air was a homogeneous substance and the four elements (earth, air, fire, and water) were capable of transforming into each other. They interpreted evaporation as transformation of water into air and condensation as conversion of air into water. “Water is generated from air, and air from water” (Aristotle 1923, 340a). Aristotle concluded that the source of stream recharge was not precipitation but water condensing in caves. “Air becomes water in the Earth” (Aristotle 1923, 349b). The Roman architect and engineer, Vitruvius Pollio (c. 30 BC) attributed both spring and river flow to precipitation and infiltration. He described springs in mountain valleys as being sourced by both rainfall and melting snow (Vitruvius 1960, 229). Vitruvius understood that clouds formed from evaporation, and he identified the source of river flow as rainfall brought by damp, southerly winds into northern latitudes (Vitruvius 1960, 230 to 231). But there was no consensus among Roman writers as to nature of the hydrologic cycle. Another explanation for the source of stream flow was the idea that there existed unseen channels inside the Earth by which seawater flows back to the land. In Naturales Quaestiones, Roman Senator and natural philosopher Lucius Annaeus Seneca (c. 4 BC to 65 AD) explained that “the sea, therefore, does not get larger, because it does not assimilate the water that runs into it, but forthwith restores it to the Earth. For the sea water returns by a secret path, and is filtered in its passage back. Being dashed about as it passes through the endless, winding channels in the ground, it loses its salinity, and purged of its bitterness in such a variety of ground as it passes through, it eventually changes into pure, fresh water” (Seneca 1910, 116 to 117). Seneca's reasoning in part was based on the Doctrine of the Macrocosm and Microcosm, the idea that the body of the individual human being (the microcosm) is analogous to the larger world (the macrocosm). “My firm conviction is that the Earth is organized by nature much after the plan of our bodies, in which there are both veins and arteries, the former blood‐vessels, the latter air‐ vessels. In the Earth likewise there are some routes by which water passes, and some by which air. So exactly alike is the resemblance to our bodies in nature's formation of the Earth, that our ancestors have spoken of veins of water” (Seneca 1910, 126).

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The Hydrologic Cycle (Continued) The modern conception of recharge by precipitation and infiltration took hold during the Renaissance when empiricism began to supersede pure logic as a preferred method for ascertaining reliable truth. The potter Bernard Palissy (c. 1510 to 1589) argued unequivocally that precipitation was the ultimate source of all stream flow but he lacked the quantitative measurements necessary to corroborate his thesis (Deming 2005). Quantitative hydrogeology began with Mariotte's colleague in the French Academy, Pierre Perrault (1611 to 1680). In De l'origine des fontaines (The Origin of Springs) (Perrault 1674), Perrault demonstrated that rainfall was sufficient to account for river flow by making quantitative estimates of both precipitation and discharge in a basin of the Seine River (Deming 2014). But Perrault was not able to discern or explain how infiltration occurred. He rejected the idea of “universal and uniform penetration” (Perrault 1967, 84). In England, Edmond Halley (1656 to 1743) was also thinking and writing about the hydrologic cycle (Halley 1686). But Edme Mariotte was the first person to quantitatively and unequivocally demonstrate that precipitation and infiltration were sufficient to account for stream flow.

The French Academy of Science Edme Mariotte was an early and important member of the l'Académie Royale des Sciences, the French Academy of Science. Academies of science were important in influencing the development of science during the 17th century. These organizations not only provided opportunities for collaboration and interaction but also published journals and books and could determine the course of research projects. The first of the scientific academies was the Accademia dei Lincei, founded in Rome in 1603. Its members included Galileo. The Accademia dei Lincei ended in 1630. It was succeeded by the Florentine Accademia del Cimento in 1657, but this organization was in existence for only 10 years (Miniati 2000). Following the persecution of Galileo in 1633 by the Catholic Church, scientific activity in Italy withered. Individuals such as the Jesuit priest Athanasius Kircher (1602 to 1680) continued scientific work, but the locus of creative activity passed from Italy to England and France. The countries of northern Europe offered more intellectual freedom (Deming 2012, 203 to 204). The oldest scientific society in continuous existence since its founding is the Royal Society of England. The activities of its members virtually defined the practice of modern science. The Royal Society was formally chartered in 1662, but its members convened informal meetings as early as 1645. In his autobiography, the mathematician John Wallis (1616 to 1703) recalled attending meetings in 1645. “About the year 1645, while I lived in London…I had the opportunity of being acquainted with diverse worthy persons, inquisitive into natural philosophy, and other parts of humane learning; and particularly of what hath been called the new philosophy or experimental philosophy” (Wallis 1725, clxi to clxiv). Similarly, in a letter of October 22, 1646, Robert Boyle noted the existence of a “new philosophical college.” This “invisible college,” Boyle explained, was not interested in metaphysical speculation. It “values no knowledge, but as it has a tendency to use” (Birch 1744, 20). The luminaries of the Royal Society included Robert Boyle, Robert Hooke, Isaac Newton, and Edmond Halley. Although arguably the Royal Society in England was a spontaneous outgrowth of individual activities, the French Academy was a deliberate invention of the Crown. The French Academy was founded in 1666 by King Louis XIV in response to a suggestion by the minister of finance, Jean‐Baptiste Colbert (1619 to 1683). The purpose was not so much the disinterested pursuit of knowledge as it was to aggrandize France and the King. In this age the prevailing economic theory was mercantilism, which prescribed increasing government power and wealth through exports and economic control (Mun 1664). Experimental philosophy was seen as a means of obtaining practical knowledge that would aid in economic development. One of the specific motivations for founding the French Academy was “to correct and improve maps and sailing charts” (Brown 1979, 213). Furthermore, it was thought that the achievements of the Academy would bring prestige and glory to the King (Stroup 1990). The power to appoint members and determine their stipends enabled the King's ministers to have a good deal of power and control over the French Academy. Colbert built the French Academy in part by recruiting foreign talent. “He scoured Europe in search of the top men in every branch of science” (Brown 1979, 213). The most illustrious of these was the Dutch mathematician Christiaan Huygens (1629 to 1695). Throughout the 17th century, membership in the French Academy remained small. The number of members varied between 19 and 34. They held regular meetings in Paris on Wednesdays and Saturdays (Figure 1). The approach and philosophy of the members were similar to those of the Royal Society in England. They rejected Aristotelean natural philosophy, embraced empiricism, and believed that scientific

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The Hydrologic Cycle (Continued) knowledge should have practical applications. Academy members also believed that experimental philosophy was a “philosophy of mankind,” and viewed themselves as members of a Republic of Letters that transcended national boundaries and parochial interests (Stroup 2000).

Figure 2: Frontispiece from Traité du mouvement des eaux et des autres corps fluide (Treatise on the Movement of Water and Other Fluid Bodies) Figure 1: French Academy members (1686). dissecting an animal. Mariotte is believed to be the central figure holding eyeglasses to his face. Engraving by Sébastien Le Clerc (1637 to 1714) (Perrault 1676).

Polymath Mariotte was a Catholic clergyman, apparently the abbot of St. Martin de Beaumont sur Vingeanne in Côte d'Or (Mahoney 2008, 114). Otherwise, very little is known about his personal life. Mariotte was apparently born around 1620 in Dijon, but the circumstances of his birth and early life are uncertain. He apparently moved to Paris sometime in the 1670s, presumably so as to facilitate participation in the activities of the Academy (Mahoney 2008, 114). Mariotte was appointed to the French Academy in 1666, the year of its formation (Wolf 1968a, 234). In his elogy, the Marquis de Condorcet called Mariotte the first philosopher in France who was devoted to experimental philosophy (de Condorcet 1799, 74). Mariotte “impressed colleagues by his open, tolerant frame of mind, his rejection of intellectual rigidity, [and] his absence of scientific dogmatism” (Sturdy 1995 9, 111 to 112). Like most of his colleagues in the Academy, Mariotte was not a specialist but a polymath. His interests encompassed hydrology, plant physiology, optics, chemistry, meteorology, and the physics of moving bodies (Mahoney 2008). Mariotte speculated on the relationship between precipitation and barometric pressure (Wolf 1968a, 94), and made experimental studies of the physical laws governing impacting bodies. He suspended balls made of ivory or soft clay from thread, observed their collisions under controlled conditions, and demonstrated the existence of conservation of momentum (Timoshenko 1983, 21). Entrusted with the design of pipes to supply water to the Palace at Versailles, Mariotte became interested in the strength of materials and conducted a series of experiments to determine the bending strength of beams. He found that “in all the materials tested, the elongations were proportional to the applied forces” (Timoshenko 1983, 21). Mariotte also experimentally studied the conditions under which a pipe would burst from the internal pressure exerted by a fluid. He found that in order for a conduit to withstand hydraulic pressure, the thickness of its walls must be “proportional to the internal pressure and to the diameter of the pipe” (Timoshenko 1983, 24). In Mariotte's Treatise of Hydrostaticks he explained “if the height of the reservatory be double, you will have double the weight of water, and consequently the metal of your pipe must be twice as thick…[and] if the diameter of the pipe be twice as great, you must have twice the thickness” (Mariotte 1718, 256). Mariotte is sometimes given credit for an independent discovery of Boyle's Law, the observation that the pressure exerted by a gas is inversely proportional to the volume it occupies. But Boyle preceded Mariotte by 17 years (Wolf 1968a, 243). In A Defense of the Doctrine Touching the Spring and Weight of the Air (Boyle 1662), Boyle recorded that his experiments

Page 18 AGS February 2018

The Hydrologic Cycle (Continued) conducted with the aid of Robert Hooke had found air “pressures and expansions to be in reciprocal proportion” (Boyle 1662, 60). The nature of light was an area of active interest and research for late 17th‐century physicists. In 1672 Isaac Newton had demonstrated that white light was not homogeneous but an amalgamation of various colors that could be separated and isolated with a prism (Newton 1671). It was, in Newton's words, “the oddest if not the most considerable detection which hath hitherto been made into the operations of nature” (Westfall 1980, 174). In De la Nature des Couleurs (Mariotte 1681), Mariotte argued that the halos which occasionally appear around the Sun and the Moon result from the diffraction of light by ice crystals in the upper atmosphere (Wolf 1968a, 271 to 272). More significant was Mariotte's discovery of the blind spot in the human eye. Mariotte was the first person to discover that there is a blind spot in human vision at the point where the optic nerve attaches to the retina. He demonstrated the existence of the blind spot experimentally to the Academy in 1666. Mariotte's discovery created a sensation (Wolf 1968a, 272). Mariotte showed experimentally that the light and heat from a fire could be separated. He focused the heat from a fire with a concave mirror and then placed a piece of transparent glass in the beam of the mirror. Light focused by the mirror passed through the glass, but heat was filtered out. This was not necessarily a step toward understanding the breadth of the electromagnetic spectrum (Wolf 1968a, 279 to 280). In the late 17th century heat and fire were still viewed largely as physical substances, a remnant of the ancient Greek theory of fire as an elemental entity (Deming 2016, 95 to 96). Mariotte was also interested in meteorology. The Italian mathematician, Evangelista Torricelli (1608 to 1647), invented the barometer in 1644 (Deming 2016, 86). It was understood almost immediately that the barometer measured the weight of the atmosphere, but the relationship between atmospheric pressure and weather was unknown. Mariotte suggested that simultaneous barometric observations be made throughout France and Germany and he attempted to link changes in barometric pressure with weather patterns (Wolf 1968a, 317).

A Treatise of Hydrostaticks Mariotte's contributions to hydraulics and hydrology were published in Traité du mouvement des eaux et des autres corps fluides (Mariotte 1686) (Figure 2). The work was translated into English by John T. Desaguliers (1683 to 1744) and published in 1718 as a Treatise of Hydrostaticks. Desaguliers' prefatory dedication notes that “nothing has yet appeared in English upon this subject, but what has been altogether trifling and imperfect” (Desaguliers 1718, iv). Mariotte demonstrated experimentally that water contain dissolved air. He boiled water for several hours to expel dissolved gasses. When frozen, the water obtained from this process was so clear that Mariotte successfully cast it into a lens that was capable of focusing sunlight intensely enough to ignite gunpowder (Desaguliers 1718, 8). If the boiled water, depleted of absorbed air, was placed in a sealed flask, Mariotte noted that it would absorb a trapped air bubble. If the flask was inverted, “in twenty‐four hours” the air bubble at the top would disappear (Desaguliers 1718, 4). If the process was repeated, air in the flask would continue to be absorbed into the water until “the water is sufficiently impregnated…[and] will suck in no more of them [air bubbles]” (Desaguliers 1718, 5). Mariotte's Bottle is a device that Mariotte invented which is designed to deliver a fixed rate of flow. It consists of a closed container with an air tube and a siphon (Figure 3). The air tube is connected to the atmosphere and is immersed in the fluid to the same level as the siphon opening (McCarthy 1934). Because the pressure at the bottom of this tube is atmospheric, the fluid pressure at the siphon opening is also maintained at this value without variance. Hydraulic head has a pressure and an elevation component (Deming 2002, 42). Because the presence of the air tube keeps the pressure component constant, so long as the elevations of the siphon ends do not change, the flow rate from the siphon is also constant. Mariotte's Bottle can be applied in any laboratory or field application in which a steady and uniform liquid flow is desired (Moore 2004). If the discharged liquid is used to force the flow of a gas, the device can also be employed as a means of obtaining a uniform rate of gas flow (Anonymous 1911, 36).

Mariotte's colleague in the French Academy, Pierre Perrault, had argued that precipitation was the source of streamflow, but he did not understand how infiltration occurred (Deming 2014). The common objection was that rainfall was insufficient to saturate soils below a certain depth. It was an old argument. In the first century AD, Seneca noted that “as a diligent digger among my vines, I can affirm from observation that no rain is ever so heavy as to wet the ground to a depth of more than 10 feet [3.0 meters]” (Seneca 1910, 117 to 118). Mariotte concurred. “Summer rains, although very plentiful,

AGS February 2018 Page 19

The Hydrologic Cycle (Continued) don't penetrate the earth above half a foot [0.15 m]” (Mariotte 1718, 16). He then explained why the observation was not conclusive. “I grant the experiment; but I maintain, that in uncultivated land, and in woods, there are several little canals, which are very near the surface of the earth, into which the rainwater enters; and that those canals are continued to a great depth” (Mariotte 1718, 16 to 17). Mariotte thus anticipated the modern theory of infiltration through macropores. A macropore is a “large continuous opening” (Beven and Germann 1982, 1311). Macropores can result from cracks and fissures in soils, or form through the activity of soil fauna and plant roots. Natural soil pipes can also be created by “the erosive action of subsurface flows” (Beven and Germann 1982, 1313). Mariotte maintained that natural springs were solely the result of precipitation and infiltration. The alternative theory was that springs arose from the condensation of aqueous vapors rising from the interior of the Earth. Mariotte objected “that supposition can hardly be maintained” (Mariotte 1718, 16). He denied the existence of sufficient cavities in the Earth, and contended that even if vapors condensed inside a cave the geometry of their collection and flow precluded the formation of a spring (Mariotte 1718, 16). Another reason for concluding that springs arose from precipitation and infiltration was the common observation that spring flow correlated with rainfall. “The summer of the year 1681, was very dry in France, which caused most of the wells and springs to be dried up in several places…which they never would have done, if water had been formed by vapors arisen from subterranean places, and condensed by the coldness of the surface of the earth” (Mariotte 1718, 18). An ancient argument against the formation of springs through infiltration was the purported observation that some springs were found at the top of mountains. Writing in the first century AD, Seneca noted that “some springs well up in the very summit of a mountain. It is plain, therefore, that the water in them is forced up or forms on the spot, since all the rain water runs off” (Seneca 1910, 118). Mariotte conceded that “there are sometimes found very high springs in the top of mountains… [and all springs] ought to have considerable heights above their heads” (Mariotte 1718, 18, 21). He described a spring “which gives a great quantity of water; and when you come very near it, you can't see above 40 feet [12.2 meters] in height of ground above it” (Mariotte 1718, 19). But further inspection revealed that there was a sufficient volume of earth above the spring to supply it through the process of infiltration. “If you look at this upper mountain from a far off [distance], you see it extend itself with a gentle shelving for above 500 fathoms [914 meters] in length, and 200 in breadth” (Mariotte 1718, 19). The most celebrated and significant of Mariotte's contributions to hydrogeology was his demonstration that precipitation alone was sufficient in magnitude to explain the yearly flow of the Seine River. Mariotte acknowledged the objection “that there does not fall in a whole year rain enough to supply the great rivers” (Mariotte 1718, 21). He then calmly refuted the point. “To solve this objection, I make use of an experiment” (Mariotte 1718, 21). Mariotte's “experiment” involved the measurement of three quantities: (1) the area of the Seine Basin, (2) annual precipitation in the Basin, and (3) annual discharge from the Seine. Mariotte measured the annual rainfall to be 17 inches (0.43 m). Wishing to err on the side of caution, he used a number of 15 inches for the annual rainfall and arrived at an estimate of about 20 billion cubic meters for annual precipitation in the Seine River Basin (Mariotte 1718, 22 to 23). Estimating the discharge from the Seine River was a little trickier because Mariotte realized that flow velocity was not constant but varied throughout the stream channel. “The bottom of the water does not go so swift as the middle, nor the middle so fast as the upper surface” (Mariotte 1718, 23). Mariotte measured the surface velocity of the Seine by placing “upon [the] water a ball of wax, loaded within with something heavier, insomuch that but very little of the wax lies above the surface of the water” (Mariotte 1718, 189). He then estimated the mean water velocity to be two‐thirds that of the surface speed (Mariotte 1718, 23). Multiplying the average flow rate by the cross‐sectional area of the river channel yielded an estimated annual discharge of about 3 billion cubic meters. As this was less than one‐sixth of the annual precipitation, Mariotte concluded that rainfall alone was sufficient to account for stream flow even if one‐third of the precipitation was lost to evaporation and another half locked up in storage (Mariotte 1718, 24). Thus the ancient controversy regarding the nature of the nature of the hydrologic cycle was finally resolved.

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The Hydrologic Cycle (Continued)

Conclusion

In this age, when the experimental method is axiomatic, it may be difficult to comprehend the revolutionary work that was necessary to liberate science from natural philosophy. For 2000 years, Aristotelean natural philosophy formed an integrated view of the world and humanity's place in it. Although the experimental method was recognized in antiquity, it was always subordinated to deductive logic. The Scientific Revolution occurred when people gradually realized the limitations of human reason. Logic was not abandoned, but subordinated to empiricism. Edme Mariotte and his contemporaries were the people who fulfilled the promise of the new epistemology by demonstrating that reliable knowledge was to be obtained through experimentation and observation.

Read more about this article at: https://onlinelibrary.wiley.com/doi/abs/10.1111/gwat.12609

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March 2018 Atlanta Geological Society PG Candidate

Workshop

Date: Saturday, March 24, 2018 Time: 10:00 am to 12:00 pm Venue: Fernbank Science Center (check-in with the receptionist for the specific classroom location) 156 Heaton Park Drive, N.E. Atlanta, GA 30307 678-874-7102 http://fsc.fernbank.edu/

Speaker: Dr. Stephen Henderson, Ph. D. Subject: Geology of Economic Mineral Deposits

Dr. Henderson will discuss the geology of economic mineral deposits. He will start with ones with an igneous origin.

Stephen Henderson has recently retired and is now Professor Emeritus of Geology at Oxford College of Emory University. Steve attended Indiana University where he earned his B.S. and M.A. degrees in geology. After working as, a petroleum geologist in Oklahoma City for several years, he went back to school for his Ph.D. at the University of Georgia, specializing in taphonomy, a sub-discipline of paleontology. Because he is responsible for all the course offerings within the geosciences at Oxford College, he has become well-versed in many geologic topics. One of his major interests has been the influence of geology on culture and especially the role of geology and landscape on historical military battles and campaigns.

Please join us and *forward this message* to anyone who might be interested in the topic. Two Professional Development Hours are available for attendees of the class. The classes are open to all, membership in the AGS is not required, but for $25 per year ($10 for students) it is quite a bargain! Please consider joining (an application is attached), the AGS is one of the most active geological organizations in the Southeast. For more information on the workshop and/or becoming a member, please visit www.atlantageologicalsociety.org or contact us at the addresses below.

Atlanta Geological Society Professional Registration Committee

Ken Simonton, P.G. [email protected]

Ginny Mauldin-Kinney [email protected]

John Salvino, P.G. [email protected]

Page 22 AGS February 2018

Fernbank Events & Activities

Fernbank Forest Wildflower Tour Adult Prom Thursday, March 22, 2018 Friday, March 30, 2018 Enjoy a guided tour of Fernbank Join us for a Prehistoric Night to Forest focusing on spring wildflowers. Remember, exclusively for ages 21+.

Learn more Learn more

Little Critters Day Treetop Tales Saturday, March 31, 2018 Saturday, April 7, 2018 Spring into family fun with live baby Enjoy a special story and activity with a animals, crafts, giveaways and more. Fernbank educator. Perfect for younger visitors. Learn more Learn more

AGS February 2018 Page 23

Wildwoods and Fernbank Forest Wildwoods features 75 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

The Secret World Inside You On view February 10 – May 6, 2018 It’s What’s Inside that Counts Meet your microbiome, the community of microbes that keep your immune system, digestive system and brain working properly. Using larger‐than‐life models, videos, interactive experiences, unique games, and immersive displays, discover what and where these microbes are, how they help us, how we sometimes disrupt them, and how we can work with them to make our lives better than ever. Learn more

Page 24 AGS February 2018

Fernbank Museum of Natural History (All programs require reservations, including free programs)

Now showing in the Fernbank IMAX movie theater:

Museum Alive 3D

February 9 – June 21, 2018 The fantasy that drives sleepovers and fires the imagination of every museum visitor is at the very heart of Museum Alive 3D—What if the exhibits could come to life? Follow one lucky visitor who stays in the museum after dark, when the most fascinating extinct prehistoric creatures rise again. Dinosaurs, a sabre-tooth tiger, giant birds and monster reptiles escape their display cases, shake off the dust and explore the museum, by means of stunning special effects. And far from being just fantasy, everything in Museum Alive 3D is firmly rooted in the latest science, through a unique collaboration between leading paleontologists and award-winning CGI artists. Audiences will be treated to a thrilling, spectacular film that both educates and entertains—because as the lights go down, the past comes roaring back to life!

Incredible Predators 3D March 23 – August 2, 2018 This exciting new giant screen film will surprise and entertain viewers with the unexpected wonders of nature that are right under our noses—in our own backyards. Spanning a seasonal year around a suburban home, the film displays a stunning array of unique wildlife images and behavior—all captured by cameras mounted inside dens and nests, and moving along the forest floor and pond bottom, to reveal its inhabitants in rare and breathtaking intimacy.

The film follows Katie, a young girl, and her modern family living next to the woods who are blind to the real-life spectacle around them, absorbed by an array of electronic devices in their busy lives. Katie gradually discovers the intricate secrets that nature has hidden so close to her front door and we experience the joy she finds in her interactions with this new world. The film reminds us sometimes in ordinary places, you can uncover extraordinary things that can transform you forever—you just need to step outside.

AGS February 2018 Page 25

AGS Officers AGS Committees

President: Ben Bentkowski AGS Publications: Open

[email protected] Career Networking/Advertising: Todd Roach Phone (770) 296‐2529 Phone (770) 242‐9040, Fax (770) 242‐8388

[email protected] Vice‐President: Steven Stokowski

[email protected] Continuing Education: Open

Secretary: Rob White Fernbank Liaison: Kaden Borseth Phone (770) 891‐0519 Phone (404) 929‐6342 [email protected] [email protected]

Field Trips: Open Treasurer: John Salvino, P.G.

Phone: 678‐237‐7329 Georgia PG Registration: Ken Simonton [email protected] Phone: 404‐825‐3439

[email protected] Past President Ginny Mauldin‐Kenney, Shannon Star George ginny.mauldin@gmailcom

AGS 2018 Meeting Dates Teacher Grants: Bill Waggener Listed below are the planned meeting Phone (404)354‐8752 dates for 2018. Please mark your calendar [email protected]

and make plans to attend. Hospitality: John Salvino, P.G.

[email protected] 2018 Meeting Schedule

April 24 Speaker Andrew Newman “Slip, Slide Membership: Burton Dixon Away: Unlocking Controls on Earthquake Behavior along the Subduction Megathrust” [email protected] May 29

June 26 Social Media Coordinator: Carina O’Bara August 28 [email protected]

September 25 Newsletter Editor: James Ferreira

Phone (508) 878‐0980

PG Study Group meetings [email protected] Contact Ken Simonton for the details.

April 28 Web Master: Ken Simonton May 26 [email protected] June 30 July 28 www.atlantageologicalsociety.org August 25

Page 26 AGS February 2018 ATLANTA GEOLOGICAL SOCIETY www.atlantageologicalsociety.org

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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

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