Florida Geological Survey News and Research - Fall 2016

Fall 2016

Greetings, and welcome to the 2016 fall edition of FGS News and Research. This issue features innovative research related to karst geology and geochemistry. At request of the Suwannee River Water Management District (SRWMD), FGS staff successfully conducted the Dead River Swallet dye trace. Results of this intensive effort are expected to aid the district as they refine groundwater flow models.  

Also in this issue, an FGS collaborative effort with Florida State University (FSU) focuses on geochemical signatures of fine layers of sediment that may have recorded past tropical storm events. In another FSU partnership, FGS researchers Seth Bassett and Barret Dyer co-authored a paper analyzing the influence of flow reversals in a coastal Florida spring. Their work is published in Nature.com’s August issue of Scientific Reports.

Our fall 2016 GEOFACT explores fulgarites, an unusual geological wonder created by lightning strikes. These glassy tubes are representations of one of nature’s most powerful releases of energy.

In closing, please join me in congratulating FGS’ Dr. Christopher Williams, Professional Geologist, who was selected as DEP’s Employee of the Month for July. Christopher also appears in a Science, Technology, Engineering and Math (STEM) educational video about coastline geology. In addition, FGS’ Assistant State Geologist, Harley Means, is featured in STEM videos on river flow and karst geology. These three films are produced and distributed by CPALMS.org as a resource to Florida educators. I invite you to enjoy these videos on aspects of Florida geosciences.


Jon Arthur

Jonathan D. Arthur, Ph.D., P.G.
Director and State Geologist
Florida Geological Survey
Florida Department of Environmental Protection


GEOFACT: Fulgurites - Florida's Shocking Geological Wonders

Did you know that lightning strikes the Earth’s surface approximately 45 times every second? Relative to the rest of North America, Florida gets more than average due to its semi-tropical climate that promotes thunderstorm activity, especially during the summer. Commonly observed types of lightning are cloud-to-cloud lightning and cloud-to-ground lightning.

Lightning occurs when particles of opposite charge, called ions, build up in clouds and on the ground. When a lightning bolt hits the ground, the discharge of electrical energy that occurs releases an enormous amount of energy in the form of heat, which can produce temperatures in excess of 50,000 degrees Fahrenheit! When lightning comes into contact with the surface of the Earth, it follows the path of least resistance and ultimately dissipates in the subsurface. The rock and sediment in the path of the lightning bolt can actually fuse or vaporize due to the extreme heat, leaving behind a glassy tube. These glassy tubes are called fulgurites and are commonly found in some parts of Florida.


Fulgurite from a sand-cut bank along the Carrabelle River in Franklin County.

Fulgurites can be categorized based upon the geologic material that was struck by lightning. In Florida, quartz sand is abundant and the fulgurites that are commonly encountered look like glass straws. They are found in areas where vegetation is sparse and the underlying sand and sandy soil has been eroded. So keep your eye out for these amazing geologic representations of one of nature’s most powerful releases of energy!

Contact:  Harley Means, P.G. Administrator


Pasek, M.A., Block, K., and Pasek, V., 2012, Fulgurite morphology: a classification scheme and clues to formation, Contributions to Mineral Petrology, Springer-Verlag Online Publication.

Pasek, M.A. and Hurst, M., 2016, A fossilized energy distribution of lightning, Scientific Reports, 6, 30586.

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FGS Conducts Cutting-Edge Karst Data Analysis

flow meter

In order to develop a better understanding of the complex groundwater systems that provide Florida with its drinking water, DEP program areas, including FGS, have been leaders in using new research techniques including dye trace studies, water-level monitoring and conduit-flow metering.

The FGS relies on dye-trace studies to establish connections between surface waters, such as springs and swallets and rivers. During a dye-trace, a non-toxic and biodegradable dye is introduced into a water system, and water samples are taken from locations that may be connected to the injection location. Laboratory analyses of the water samples are used to determine if there is a connection, the water flow and the dye travel time. You can read about the recent Dead River dye trace conducted at the FGS in this issue of FGS News and Research. 

Once the direction and rate of water flow has been established with a dye trace, some surface features undergo water-level monitoring. This allows researchers to determine the effects of precipitation, groundwater recharge or (for coastal systems) tidal elevation on water flow. The FGS has placed pressure sensors in selected karst windows, such as sinkholes, that are known to be connected to an underlying conduit system.

Conduit flow-metering is a technique pioneered and refined by the FGS, with the assistance of the Florida cave diving community. The FGS has numerous flow-meters installed in the conduits that contribute water to several of Florida’s freshwater springs. These conduit meters provide high resolution, time-series data that describe the velocity and direction of water flow, along with other parameters such as the temperature, conductivity and pressure. Conduit flow-metering is just one example of FGS' unique contributions to the advancement of the science of karst hydrogeology.

After more than a decade of intensive research, it is evident that Florida's karst aquifers respond rapidly to changing hydrologic conditions. For example, research has shown that, under the proper local conditions, some springs can rapidly switch from discharging groundwater to siphoning surface waters. Based on the data collected by conduit meters in both the Wakulla Karst Plain area and the Suwannee River basin, many springs are now known to be dynamic points of exchange between groundwater and surface water, rather than simple groundwater discharge points, as previously believed.

Contact: Seth Bassett, Environmental Specialist III

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Dead River Dye Trace a Quick Success

Dye Trace

What would you think if you saw someone pouring 100 pounds of fluorescent green dye into an area of disappearing water? While this neon green liquid may look like something out of a science fiction novel, it is in fact a non-toxic, biodegradable and environmentally safe liquid used for tracing the direction of groundwater through Florida’s complex aquifer systems.

Located in central Hamilton County in North Florida, the Alapaha River flows from Southern Georgia south to the Suwannee River. Connected to the river by a short run is a unique geologic feature with a rather ominous name: the Dead River Swallet. A swallet is a point where surface water leaves the surface and flows underground. The Suwannee River Water Management District (SRWMD) recently solicited the help of the FGS to investigate the destination of the swallet’s disappearing waters. To accomplish the task, the FGS introduced 100 pounds of fluorescent green dye into the disappearing Dead River on June 22, 2016.

Like many of the rivers in North Florida, the Alapaha River is heavily influenced by the karst geology in which it has formed. Karst is a generic term, which refers to the characteristic terrain produced by the chemical weathering and dissolution of limestone or dolomite, the two most common carbonate rocks in Florida. Landforms typical of a karst topography include sinkholes, swallets, springs, caves, and reappearing streams. One example of karst topography, the Dead River Swallet, is located approximately 3 miles southeast of Jennings on the south side of the Alapaha River on SRWMD conservation land.

Both SRWMD and FGS had ideas as to where the dye might reemerge after traveling through the Floridan Aquifer system, as most of the region’s groundwater flows south towards the Suwannee River. However, where the water specifically reemerged after entering the Dead River Swallet and how fast it would arrive there was unknown. The two most likely discharge points were the Alapaha and Holton Creek rises, large springs located along the Suwannee River, approximately 10 miles south of the Dead River Swallet. To capture the emerging dye, sampling stations were established at various locations along the Suwannee River, to collect water samples every six hours. Some sampling stations that were less likely to receive the dye were equipped with charcoal packets, which were collected weekly and would have absorbed the dye if it had been in the water flowing over them.

On June 28, six days after the dye was introduced into the Dead River Swallet, the dye was visibly observed emerging from the Alapaha Rise, meaning the water was traveling underground at a minimum of 350 feet per hour! Success was experienced again a day later, June 29, at Holton Creek Rise, where the water was observed to be visibly green.

The FGS continued collecting samples at each of the eight locations through the middle of August in an effort to capture the dye at various concentrations. This will help establish flow paths and travel times of the Floridan Aquifer once it enters the Dead River Swallet from the Alapaha River and has helped SRWMD and FGS better understand the physical nature of the aquifer and how to better manage the groundwater within it.

Contact: Clint Kromhout, P.G. Administrator

Tom Greenhalgh, P.G.

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FGS Works with Researchers on National Science Foundation Funded Project


It may be possible to reconstruct the history of major storm events along Florida’s coast, which might help researchers view storm activity patterns, potentially providing clues for predicting future storms. Dr. Yang Wang from Florida State University (FSU), Dr. Joe Donoghue from the University of Central Florida (UCF), and staff from the FGS are collaborating on a project funded by the National Science Foundation to identify layers of sediment and geochemical signatures from past tropical storm events.  Coastal lakes at Bald Point, in Franklin County, and Western Lake, in Grayton Beach State Park, were selected as sample sites due to their proximity to the coast and their potential to contain undisturbed sediment records.

During the summer, the research team conducted field work that involved retrieving sediment cores from lake bottoms and collecting water samples from three lakes within the study area. Once the cores and water samples were collected, they were brought back to the FGS headquarters in Tallahassee where the cores were sectioned to prepare them for laboratory analyses. The laboratory work will be conducted by graduate students from both FSU and UCF.

National Science Foundation Article 2


The study is ongoing and additional study sites are being chosen for future field work that may include sites in the Everglades and along the Big Bend coastline. The researchers hope to show that there are identifiable changes in the sediment layers in these lakes that identify storm events. The geochemical signatures of various stable isotopes contained within these layers may also record information about storm frequency, intensity and other climate information that may help in reconstructing the history of storm events along the state’s coastline. By looking at the history of storm events, it may be possible to see patterns that could give researchers a better understanding of storm activity and increase our ability to predict future storms.  

               Contact: Harley Means, P.G. Administrator

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Employees Develop Understanding of Selves and One Another Through True Colors Training

True Colors

“I color my whole world,” Tippy Amick, Ph.D. explained to FGS in July. Amick, training manager “with over 25 years of experience in shaking up organizations” (tippyamick.com), is one of many professionals worldwide certified to teach the methodology of True Colors® Intl. “We are all very different critters,” Amick explained.

So, what is True Colors? True Colors allows those in a group or organization to better understand themselves, as well as one another, by recognizing people based on four personality types: green, gold, orange and blue. The theory is that everyone has a unique combination of these four types of colors, often with one being predominant.

During the training, participants are led through several exercises to educate them on the meaning behind the four personality types. Once the personality test is administered, results are shared so that the group can gain an understanding of the values that most strongly make up the organization. In the case of the FGS, employees are primarily green (intellectual, conceptual, analytical and perfectionistic) and secondarily gold (loyal, dependable, prepared, organized and sensible).

The training also involved exercises allowing staff to understand communication obstacles between different personality types. For example, a “green” person may think they are being focused and direct, while they may be perceived as rude or cold, while a blue person may feel they are expressing concern when others perceive the behavior as invasive.

At the end of the training, many employees felt that they learned a great deal about each other. Professional Geologist Dan Phelps described the training as “useful” and commented, “I realize now that my supervisor and I have a lot in common – we are both primarily orange.” Administrative Assistant Mary Esposito said, “I gained tremendous insight into how others may view me. This will change what I do, so that I can adjust my own behavior to relate to those different from me. I think this will make our office a better work environment.”

Contact: Sarah Erb, OMC Manager

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