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William E. Doll

John White

John is a multi-disciplined scientist who graduated from Alfred University (BA Biology), completed an undergraduate major in Geology at The University of Tennessee, Knoxville and then completed an MS in Geology there with a thesis focus on deltaic depositional environments. His ongoing career in the oil and gas industry began in 1973 where early on John was cross trained in Geophysics which was his primary career responsibility in onshore and offshore conventional reservoir exploration and production assignments in many of the US basins.  His Geophysical unconventional reservoir experience began in 2010 in the Barnett Shale and continued to unconventional reservoirs in West Texas.  John retired from Devon Energy Corporation in Oklahoma City in 2013 at the level of Senior Geophysical Advisor and immediately began an active consulting career focusing in West Texas.  He is currently under contract with Brahman Resource Partners, Houston, Texas.

In conjunction with oil and gas consulting, John maintains apiaries on his Middle Tennessee properties that support a honey business which began in 2013.  Beekeeping has led him back to his Biological interests which have been expanded to include various types of flora that are pollen and nectar sources for bees; resulting in a passion for wildflower photography, subsequent cataloging of photographs based on scientific names and making presentations to various bee associations in Tennessee.  As for his Geologic interests, he enjoys field trips which provide opportunities to add mineral and fossil specimens to his collection, as well as working with students and professors in the Department of Earth and Planetary Sciences at UT.

John is the father of three children and married for 45 years where he lives with his wife Debby, in Seymour, Tennessee; their final stop after living in numerous locations throughout the US.

Christina Vivano

Twitter: @cviviano

I grew up outside Portland, Oregon and have always been interested in math and science. After taking my first geology courses during my undergraduate at Colgate University, I knew a more multidisciplinary field appealed to me. I was fortunate enough to identify the University of Tennessee’s strong expertise in Planetary Science in my search for graduate school programs, and received my PhD under the guidance of my advisor, Dr. Jeff Moersch, in 2012.  Within a week of my dissertation defense, I began a postdoc at the Johns Hopkins University Applied Physics laboratory in Laurel, Maryland, under Dr. Scott Murchie, PI of the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM).  After two year, I was hired on as a staff scientist at APL and continue in that role today. 

Generally, my research pertains to the evolution of Martian crust over time, including the environments that existed during its early history as preserved in the rock record.  I utilize visible/near-infrared and thermal infrared spectroscopy to gain insight into the composition of the surface exposed today. Presently, I focus on the variability in mineral signatures as identified through the CRISM visible/near-infrared hyperspectral imager. Ultimately, understanding the geologic origin of the mineral diversity exposed at the surface today provides context for assessing the habitability of past surface and subsurface conditions on Mars. 

Most of my days are spent at the computer processing and analyzing images from the CRISM instrument, integrating information from other Mars datasets, coding up tasks to simplify these processes, writing proposals for grants (how I maintain funding to do my research), writing and editing manuscripts, administrative tasks to deal with awarded grants and generally working at the lab, and less exciting stuff like answering emails.  The work is incredibly rewarding, and the framework at APL gives me the support to pursue my research interests, as well as the ability to participate in new planetary instrumentation and mission development opportunities.

In my free time, I enjoy getting outside for a variety of outdoor adventure/sport activities, rock climbing, knitting, painting and drawing, and visiting my family and friends. Please contact me if you have questions about living in the greater DC area, working in a research/lab setting, supporting your salary via research grants, or anything else.

Syreeta Dickerson Vaughn

Syreeta Vaughn is a senior nuclear safety specialist at the Oak Ridge National Laboratory in Oak Ridge, Tennessee. In her work, she identifies hazards, evaluates accident scenarios, and is responsible for developing and implementing the nuclear safety controls to mitigate those hazards for Department of Energy category 1, 2, and 3 nuclear facilities. She has over 15 years of experience in nuclear safety and has supported various programs and projects at Y-12 National Nuclear Security Complex, Pantex Plant, Savannah River Site, and Oak Ridge National Laboratory.

After graduating from Carter High School in Strawberry Plains, Tennessee, Mrs. Vaughn earned her Bachelor of Science degree, in geology, from Florida State University in 2002. In 2005, Vaughn became the first African American woman to earn a Master of Science degree in earth and planetary science from the University of Tennessee. After her first MS in geology, Mrs. Vaughn returned to UT to earn a second MS in industrial engineering in 2013, adding two graduate diplomas to her toolbox.

Vaughn is an active community member and currently serves as a member on the Tickle College of Engineering Board of Advisors and the EPS Advisory Board. Extremely active at UT, Vaughn was appointed to the UT Advisory Board by Governor Bill Haslam in 2018. As part of the board, she provides input on planning and budgeting for the Knoxville campus, ensuring manageable growth for years to come. She is an active member of Alpha Kappa Alpha Sorority, Inc., and is a member of the Jack and Jill of America, Inc., organizations which nurture which focus on civic service and philanthropy. Syreeta also serves as a steering committee member for Connect Knox and actively supports the Knoxville Area Urban League. In her spare time, she also mentors’ young professional engineers and high school students interested in STEM careers.

Vaughn was named one of Knoxville’s “40 Under 40” in 2013. In 2016, she was featured in “Without Limits,” a TEDx Knoxville talk. Syreeta was also awarded the UT Alumni Promise Award in 2019 along with a ranking of top engineer on her job.

Among all her achievements, her greatest achievement is wife to Clarence Vaughn, III, and mother to Nia, Jada, and Zya.

Ronald M Tisdale

Originally from Columbia, South Carolina, Ron spent most of his formative years in Alabama. Like many geoscientists, he grew up with a love of the outdoors and commonly spent vacations with family in the smokies where he developed a love for East Tennessee. He attended undergraduate school at the University of Alabama in Tuscaloosa where in his junior year he began his geology career working on campus at the Geological Survey of Alabama.

Between graduate and undergraduate school, he interned with Union Oil Company of California in Jackson, Mississippi working on basin analysis with stratigraphic studies in Mississippi, Alabama, Florida, and Georgia. Following this internship, he also worked for a geotechnical firm in Birmingham doing ground water studies, subsidence evaluation in karst terrain, and coal resource drilling.
With this early professional experience, he returned to graduate school for his master’s degree with a focus on sedimentology and the goal of a career in the petroleum industry. Tennessee (UTK) was his first choice where he studied under Dr. Garrett Briggs working on sedimentary depositional modeling of Carboniferous depositional systems in the Cumberland plateau of East Tennessee.
Following graduate school, he was employed by Union Oil Company of California (UNOCAL – now Chevron) for 11 years as an area exploration and development geologist in Jackson, Mississippi and Lafayette, Louisiana working in a variety of onshore and offshore Gulf Coast Basins from South Louisiana to South Florida. He worked in multidisciplinary teams with geologists, geophysicists, and reservoir engineers successfully developing fields in both normal and pressured environments with objectives as deep as 25,000’. He was also a college recruiter for UNOCAL, as well as a mentor for young geologists. These responsibilities were often personally rewarding as he watched young geologists develop into successful professionals.

Following his years with UNOCAL, he moved to the energy subsidiary of a major utility in Birmingham, Alabama, Alagasco Energy, which became Energen Resources. Here he spent 28 years as an area geologist, exploration manager, geologic manager, and vice-president of geology. During this time, he was part of a group of industry professionals that grew the company from a small independent in the Black Warrior Basin with roughly twenty employees to a top twenty independent with 470 employees.

Over the years the company was active in most prominent hydrocarbon producing areas of the domestic United States. He was involved with development, unitization, secondary recovery, and acquisition projects in the Powder River, Williston, San Juan, Permian (conventional), Arkoma, and Mid-Continent basins, onshore Gulf Coast and offshore Texas, East Texas, North Louisiana, Mississippi, Black Warrior Basin (conventional), and the Appalachian Basin.

Ron was also involved with the initial drilling of unconventional coalbed methane wells and development in the Black Warrior Basin of Alabama where Energen had operations in over 2,000 wells. He was also part of a team from Energen that consulted corporately in coalbed methane development opportunities in the United Kingdom, France, and Australia.

During the last 10 years of his career, Energen became one of the early players and developers of horizontal drilling and fracturing of unconventional shale reservoirs in the Permian Basin. It was the primary focus of the company at the time of his retirement.

With Energen isolated from the mainstream oil and gas industry in Birmingham, Ron developed a geoscience department of highly skilled and experienced geologists, geophysicists, petrophysicists, and geotechnical support staff that was current in technology and consistently competitive with industry plays throughout the United States. At his retirement, Energen had grown from a subsidiary with limited reserves of 234 MBOE to almost 500 MMBOE of reserves and $5 billion in total assets.

Now semi-retired, he continues to work as the Director of Geoscience of oil and gas evaluation for Toccoa Resources, LLC a small geologic consulting firm in Birmingham.  He is an AAPG Certified Petroleum Geologist and a registered Professional Geologist in Wyoming and Alabama. He serves on the University of Alabama and University of Tennessee Knoxville geoscience advisory boards, the Birmingham UTK  alumni board, and is active in his local church. He and his wife Nancy have been married for 48 years. They have a son and daughter in church ministry and four grandkids.

Christopher Dean Singleton

I grew up on the other side of the Smokies near Asheville, North Carolina, where I played lots of sports, started fishing, mountain biking, golf, snow skiing, water skiing, camping, hiking, etc. 

I started at the University of Tennessee in the fall of 1990 where I would eventually take Geology 101 for what I thought was an elective class that I liked so much, and after talking to Otto Kopp and Don Byerly, I changed my major to Geology.  I graduated from UT in the spring of 1995 and began a 27-year career in environmental and hydrogeology.

While at UT in 1994, immediately after completing geology field camp, I met Tracie Seymour at Cotton Eyed Joes who later became my wife.  She and I have two daughters, Haley (freshman in college) and Cadence (8th grade).

In 2005 I started Singleton Environmental, Inc. in Asheville, North Carolina focusing on soil and groundwater remediation.  Since 2005 we have successfully closed out hundreds of sites using various remedial technologies including soil excavation, mechanical and microbial soil and groundwater remediation.

During my spare time my family and I enjoy traveling, hiking, mountain biking, camping, etc.  I’m not very active on social media, however,
I can be found on Facebook and LinkedIn.

Dibyendu “Dibs” Sarkar

Valerie S. Reynolds

Originally from Asheville, NC, I earned my BS in Geology from UNC Wilmington. After traveling around the country, I moved to Knoxville to earn my Master’s and PhD in Geology from the University of Tennessee where I studied the geochemistry of rocks from Hawaii, Mars, and asteroids under the direction of Dr. Hap McSween. Between graduate degrees, I worked for an environmental consulting firm in Knoxville for 2 years. After earning my PhD, I worked at the Smithsonian Museum of Natural History in Washington, DC for 2 years while continuing research on meteorites from Mars in addition to iron and stony-iron meteorites from asteroids. Then, I accepted a one-year teaching position at The University of the South in Sewanee, TN before moving to Maine to teach at Colby College for 4 years.

I moved back to NC in 2012 and have taught at UNC Charlotte ever since. The courses I teach regularly within the Geography and Earth Sciences department include Mineral Resources and Sustainability, Mineralogy, Igneous and Metamorphic Petrology, and a general education course on Critical Thinking and Communication. Occasionally, I teach Physical Geology and high-temperature Geochemistry. I am one of the faculty advisors for our student GEO Club, and I am the undergraduate coordinator for our Geology and Earth & Environmental Sciences degrees, so I do a lot of academic advising, which I truly enjoy. The path to my current profession was not a direct one, and I encourage everyone to take the path that works best for them.

Ashley Ramsey

Ashley is a trusted advisor to municipalities, regulatory agencies, and private-sector clients who recognize her as a leader in developing and executing integrated solid waste management plans and environmental compliance programs across multiple states and at large-scale industrial and federal facilities.

On behalf of clients, Ashley integrates strategic planning and stakeholder engagement with her deep understanding of environmental regulations to deliver practical, data-driven solutions for complex waste management challenges. Her technical expertise spans integrated solid waste and materials management master planning; waste characterization; operational assessments of convenience centers, transfer stations, material recovery facilities (MRFs), and landfills; permitting; regulatory compliance; feasibility assessments; and rate and cost-of-service studies. She also conducts operational due diligence to assess infrastructure and regulatory compliance, recommend improvements, and support post-acquisition integration.

Ashley has led and supported multiple statewide solid waste planning initiatives in the Eastern United States and Caribbean, tailoring solutions to meet diverse regulatory frameworks and state-specific needs. She has helped clients develop and implement regulated waste management compliance programs, in addition to executing Spill Prevention, Control, and Countermeasure (SPCC) plans and Stormwater Pollution Prevention Plans (SWPPPs) for facilities throughout the southeastern United States. She has managed environmental compliance programs for more than 30 landfills and transfer stations, as well as for multiple large-scale industrial and federal sites, helping clients adhere to evolving environmental standards and supporting their long-term sustainability goals.

Beyond her solid waste expertise, Ashley has directed numerous environmental site assessments and overseen soil, sediment, and groundwater investigations. She has helped design and implement various remedies across the Southeast, supporting clients as they navigate complex regulatory landscapes and effectively mitigate environmental risks.

Ashley is active in the Solid Waste Association of North America (SWANA), serves on their Young Professional Steering Committee, and is a graduate of the organization’s Young Professional Leadership Academy. She is affiliated with the Georgia, Caribbean, and Tennessee SWANA Chapters. She also chairs The University of Tennessee Department of Earth, Environmental, and Planetary Science Advisory Board. A frequent presenter at state and national conferences, Ashley shares insights on waste management innovation, environmental stewardship, and emerging trends in sustainability and circular economy practices.