EWING, Thomas E., Bureau of Economic Geology, University of Texas at Austin, Austin, TX; and Frontera Exploration Consultants, San Antonio TX




            In June 2013 I began to put together a summary volume on the geology of Texas as geologists currently understand it, to be designed for general audiences. At present, the draft is completed and we are in review and editing/compositing stage; anticipated printing date is September, 2015.  The book is fully illustrated in color, and around 300-340 pages long. It includes a comprehensive series of time-stratigraphic charts and an atlas of paleogeography and other features.

            To write such a summary involved summarizing and synthesizing hundreds of geological reports and articles. That has led to some interesting new insights, a few of which follow:

  • Precambrian history is long and complex, we need more subsurface samples! The biggest question is the 'juvenile crust' section of the Southern Granite-Rhyolite province, how it gets added and how it's reworked into the Llano Orogen.

  • Latest Precambrian-Middle Cambrian rifting includes activity on the Devils River trend as far as Van Horn. Interestingly, Cambrian and Ellenburger isopachs don't show subsidence into that area, but instead towards San Antonio.

  • The story of rifted and displaced terranes south of the craton is newly considered and revised. One terrane (south of the former Marathon Basin, south of the Devils River) was sheared off to form 'Cuyania' in South America in mid-late Ordovician. It's possible that Sabinia (the Sabine Block) is also a part of North America and not exotic - but we need crazy deep drilling to be sure!

  • Ouachita-Marathon deformation is a 'soft docking' not a high-impact continental collision. It doesn't seem to explain the Late Paleozoic uplifts and basins, which are more consistent with SW-NE compression and related strike-slip.

            The project also includes a website (now in beta), which will be part of the BEG website. It will include statewide information; some material from the book; and a series of 70-plus 'Great Places to View Texas Geology'. These are miniature field trip guides to highlight publicly accessible places to be wowed by Texas rocks and landscapes. Each site includes a nontechnical discussion of what you see, why it's important; a gallery of photographs; and a few references and websites for more information.

            In West Texas these sites include: the Guadalupe Mountains (4 sites), Balmorhea/Davis Front, Marathon Basin, Odessa Meteor Crater, Big Spring, Iraan-Fort Lancaster, and Langtry-Pecos Canyonlands - plus some 11 sites in the Trans-Pecos mountains. In Northwest Texas, we add: Muleshoe Depression, Blanco Canyon, Caprock Canyons, Palo Duro, and Lake Meredith area.

Speaker Dr. Thomas E. Ewing
Dr. Thomas Ewing is a geoscientist with over 33 years of experience in hydrocarbon exploration and research. He is a Registered Professional Geoscientist in the State of Texas (#1320) and an AAPG/DPA Certified Petroleum Geologist (#4538), and holds certification #1610 from SIPES.             He received a B.A. in Geology from ...

Dr. Thomas Ewing is a geoscientist with over 33 years of experience in hydrocarbon exploration and research. He is a Registered Professional Geoscientist in the State of Texas (#1320) and an AAPG/DPA Certified Petroleum Geologist (#4538), and holds certification #1610 from SIPES.

            He received a B.A. in Geology from the Colorado College (1975), an M.S. in Geochemistry from New Mexico Institute of Mining and Technology (1977), and a Ph.D. in Geological Sciences from the University of British Columbia (1981).

            Dr. Ewing was a research geologist for four years at the Texas Bureau of Economic Geology in Austin, working on Gulf Coast geopressured reservoirs, serving as a co-author of the "Atlas of Texas Oil Reservoirs", and compiling the Tectonic Map of Texas.  Since 1985 he has been co-owner of Frontera Exploration Consultants, Inc., a San Antonio-based geoscience consulting company; he has consulted to numerous clients in South Texas, New Mexico and elsewhere. He worked with Venus Oil and Venus Exploration from 1985 to 2005 as staff consultant and Senior Explorationist, playing a main role in its successful exploration in the Yegua Trend of the Gulf Coast Basin, the Cotton Valley trend of Texas and Louisiana, and in West Texas and Kansas. He is now a partner in Yegua Energy Associates, LLC, which is continuing hydrocarbon exploration in these trends.

            In 2013, Dr. Ewing received a half-time appointment with the Texas Bureau of Economic Geology as project director to develop "Texas Through Time", an illustrated book and website on the geologic history and earth resources of Texas for a general audience.

            Dr. Ewing is a member of many regional and national professional societies. He has served as Treasurer, Vice-President and President (2007-08) of the AAPG Division of Professional Affairs, and has received Life Membership in the DPA (2014). He is an AAPG Delegate from the South Texas Geological Society, and served as Vice-Chairman of the AAPG House of Delegates in 1992-93. He is also served as President of the Energy Minerals Division of the AAPG (1999-2000), and received Honorary Membership in that Division in 2009. Most recently, he completed service as Vice-President for Sections of AAPG (2012-14). He served as President of the South Texas Geological Society in 1990-1991, and as General Chairman of the 1996 GCAGS Convention in San Antonio. He received Honorary Membership in the South Texas Geological Society in 2009, Honorary Membership in the GCAGS in 2010, and BEG Alumnus of the Year in 2011.

            Tom has spoken extensively at local, regional, and national geological meetings and published over 75 papers and abstracts. Among other awards, he has twice received the Gulf Coast Section AAPG Levorsen Award (1982 and 1999), and has received the AAPG Distinguished Service Award. He has written articles on Gulf Coast geology and hydrocarbons, the geology and tectonics of Texas, and history and urban geology of the San Antonio area. He wrote the popular guidebook “Landscapes, Water and Man: Geology and Man in the San Antonio Area” published by the South Texas Geological Society in 2008.

            In his spare time, he leads field trips in South Texas, and directs a 60-voice German men’s chorus, the San Antonio Liederkranz.

Full Description
Organizer PBS-SEPM


Tue, Feb. 17, 2015
11:30 a.m. - 1 p.m.
(GMT-0500) US/Central

Event has ended


Midland Center
105 N. Main
Midland, Texas 79701
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