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Dive into the research topics where Linda C. S. Gundersen is active.

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Featured researches published by Linda C. S. Gundersen.


Gsa Today | 2010

Geoinformatics: Transforming data to knowledge for geosciences

A. Krishna Sinha; Zaki Malik; Abdelmounaam Rezgui; Calvin G. Barnes; Kai Lin; Grant Heiken; William A. Thomas; Linda C. S. Gundersen; Robert Raskin; Ian Jackson; Peter Fox; Deborah L. McGuinness; Dogan Seber; Herman Zimmerman

An integrative view of Earth as a system, based on multidisciplinary data, has become one of the most compelling reasons for research and education in the geosciences. It is now necessary to establish a modern infrastructure that can support the transformation of data to knowledge. Such an information infrastructure for geosciences is contained within the emerging science of geoinformatics, which seeks to promote the utilization and integration of complex, multidisciplinary data in seeking solutions to geoscience-based societal challenges.


Environment International | 1996

Mapping the radon potential of the united states: Examples from the Appalachians

Linda C. S. Gundersen; R. Randall Schumann

The geologic radon potential of the United States was recently assessed by the U.S. Geological Survey. Results indicate that approximately 33% of the U.S. population lives within geologic provinces where the average indoor radon levels have the potential to be greater than 4 pCi/L (147 Bq/m3). Rock types most commonly associated with high indoor radon include: 1) Uraniferous metamorphosed sediments, volcanics, and granite intrusives, especially those that are highly deformed or sheared. 2) Glacial deposits derived from uranium-bearing rocks and sediments. 3) Carboniferous, black shales. 4) Soils derived from carbonate rock, especially in karstic terrain. 5) Uraniferous fluvial, deltaic, marine, and lacustrine deposits. Different geologic terrains of the eastern United States illustrate some of the problems inherent in correlating indoor radon with geology. The Central and Southern Appalachian Highlands of the eastern United States have not been glaciated and most soils there are saprolitic, derived directly from the underlying bedrock. Regression analyses of bedrock geologic and radon parameters yeild positive correlations (R > 0.5 to 0.9) and indicate that bedrock geology can account for a significant portion of the indoor radon variation. In glaciated areas of the United States such as the northern Appalachian Highlands and Appalachian Plateau, the correlation of bedrock geology to indoor radon is obscured or is positive only in certain cases. In these glaciated areas of the country, it is the type, composition, thickness, and permeability of glacial deposits, rather than the bedrock geology, that controls the radon source.


Environment International | 1996

Geologic and climatic controls on the radon emanation coefficient

R. Randall Schumann; Linda C. S. Gundersen

Abstract Geologic, pedologic, and climatic factors, including radium content, grain size, siting of radon parents within soil grains or on grain coatings, and soil moisture conditions, determine a soils emanating power and radon transport characteristics. Data from field studies indicate that soils derived from similar parent rocks in different regions have significantly different emanation coefficients due to the effects of climate on these soil characteristics. An important tool for measuring radon source strength (i.e., radium content) is ground-based and aerial gamma radioactivity measurements. Regional correlations between soil radium content, determined by gamma spectrometry, and soil-gas or indoor radon concentrations can be traced to the influence of climatic and geologic factors on intrinsic permeability and radon emanation coefficients. Data on soil radium content, permeability, and moisture content, when combined with data on emanation coefficients, can form a framework for development of quantitative predictive models for radon generation in rocks and soils.


Geology | 1989

Role of ductile shearing in the concentration of radon in the Brookneal zone, Virginia

Alexander E. Gates; Linda C. S. Gundersen

A positive correlation exists among surface gamma radiation, uranium concentration, and the angles between C and S bands in mylonite and radon in the soils overlying the Brookneal zone of the southwest Virginia Piedmont. Part of the Brookneal zone lies within the compositionally homogeneous Melrose granite, which is undeformed to the west of the zone. The angle between C and S bands in mylonitic Melrose granite varies from 43{degree} in the westernmost protomylonte to near 0{degree} in the easternmost ultramylonite. Radon in the overlying soils increase from 450 picocuries/litre (pCi/L) in underformed granite to as much as 4100 pCi/L in ultramylonite. In undeformed granite, uranium is hosted in titanite and zircon. During mylonitization, uranium was redistributed into the foilation and is associated with hematite and fine-grained monazite. Uranium, however, is in constant proportion to thorium, indicating little introduction of new uranium into the mylonite zone. An increase in the uranium concentration from 1 to 2 ppm in undeformed granite to 7 to 8 ppm in ultramylonite may be the result of volume loss during shearing.


Eos, Transactions American Geophysical Union | 2008

Enabling Global Collaboration in the Geosciences: Geoinformatics 2008; Potsdam, Germany, 11–13 June 2008

Jens Klump; Lee Allison; Kristine Asch; Peter Fox; Linda C. S. Gundersen; Ian Jackson; Peter Loewe; Walter S. Snyder; Bernd Ritschel

Scientists are facing an increasing flood of data and information in the Earth sciences from which they try to distill knowledge. The emerging discipline of geoinformatics brings together the tools necessary to create and make accessible the knowledge needed to respond to societys complex challenges, such as climate change, new energy and mineral resources, new sources of water, and protecting environmental and human health. Globalization of geoinformatics-based research and education in support of meeting societal challenges was the theme for the Geoinformatics 2008 conference, which was held at the German Research Centre for Geosciences, in Potsdam, Germany. Participants came from China, France, Germany, Japan, Netherlands, Russia, Switzerland, the United Kingdom, and the United States, representing academic institutions, national research centers, and government agencies.


Journal of Geodynamics | 1995

Mechanical response, chemical variation, and volume change in the Brookneal and Hylas shear zones, Virginia

Linda C. S. Gundersen; Alexander E. Gates

Abstract Changes in volume and chemical composition were compared with strain indicators measured in two Alleghanian shear zones in granitoid plutons within the Virginia Piedmont. Both shear zones have measurable kinematic indicators that consistently record dextral strike-slip movement. The Brookneal zone, in the Melrose Granite, exhibits one ductile deformation event whereas the Hylas zone, in the Petersburg Granite, records both brittle and ductile events. Comparison of the chemical variation and volume change for each of the shear zones yields several surprising similarities given the differences in deformational history and structural style of the two zones. Overall, both zones experienced volume decreases during deformation from undeformed to ultramylonitic. Silica, K, and U increased in both zones with decreases in Fe, Mg, Sr, Ti, Mn, Y, Nb, Zr. Changes in element behavior with incremental changes in strain are different in each zone and appear to be directly related to the style of deformation and strain processes operating at each deformational stage. Chemical data from the Brookneal shear zone clusters into three groups corresponding to weak deformation, moderate strain, and ultramylonite. Deformation in the Hylas shear zone is more complex and abrupt changes in volume and element behavior may be related to brittle events late in the deformation history. The choice of immobile elements for mass balance and volume calculations was based on the petrography of the samples. The concentration of titanite in the Melrose Granite changes from several percent in the undeformed rock to absent with very minor Ti oxides in the ultramylonite. A similar decrease in most accessory minerals takes place in the Hylas zone; however monazite increases significantly. Titanium mobility is implied in the results of the chemical analyses and volume calculations. Further, it is postulated that the fluid source for the shear zones includes dehydration reactions in the granites themselves and may include other sources, especially in the case of the Hylas zone. Pressure driven fluid movement and mechanical response of the deforming rocks may be responsible for some of the observed variations in the chemistry and volume of the zones.


Geoethics#R##N#Ethical Challenges and Case Studies in Earth Sciences | 2015

Formulating the American Geophysical Union’s Scientific Integrity and Professional Ethics Policy: Challenges and Lessons Learned

Linda C. S. Gundersen; Randy Townsend

Creating an ethics policy for a large, diverse geosciences organization is a challenge, especially in the midst of the current contentious dialogue in the media related to such issues as climate change, sustaining natural resources, and responding to natural hazards. In 2011, the American Geophysical Union (AGU) took on this challenge, creating an Ethics Task Force to update their ethics policies to better support their new Strategic Plan and respond to the changing scientific research environment. Dialogue with AGU members and others during the course of creating the new policy unveiled some of the following issues to be addressed. Scientific results and individual scientists are coming under intense political and public scrutiny, with the efficacy of the science being questioned. In some cases, scientists are asked to take sides and/or provide opinions on issues beyond their research, impacting their objectivity. Pressure related to competition for funding and the need to publish high quality and quantities of papers has led to recent high-profile plagiarism, data fabrication, and conflict of interest cases. The complexities of a continuously advancing digital environment for conducting, reviewing, and publishing science has raised concerns over the ease of plagiarism, fabrication, falsification, inappropriate peer review, and the need for better accessibility of data and methods. Finally, students and scientists need consistent education and encouragement on the importance of ethics and integrity in scientific research. The new AGU Scientific Integrity and Ethics Policy tries to address these issues and provides an inspirational code of conduct to encourage a responsible, positive, open, honest scientific research environment.


Eos, Transactions American Geophysical Union | 2006

Toward broad community collaboration in geoinformatics

Peter Fox; Linda C. S. Gundersen; Kerstin A. Lehnert; Deborah L. McGuinness; Krishna Sinha; Walt Snyder

A Town Hall meeting at the upcoming AGU Fall Meeting will be held under the theme “Envisioning the future of Earth science data and knowledge access through a broad national geoinformatics collaboration.” Geoinformatics (GI) is understood as a distributed, integrated digital information system and working environment that provides innovative means for the study of the Sun-Earth system and other planets through the use of advanced information technologies. It is an emerging science and technology frontier, and it is increasingly recognized as a relevant part of the broader cyberinfrastructure for the sciences (see U.S. National Science Foundation Blue Ribbon Panel Report at http://www.nsf.gov/od/oci/reports/toc.jsp), both within the academic and applied Earth and planetary science and computer science communities as well as in federal and state agencies.


Geological Society of America Special Papers | 1992

Geology of radon in the United States

Linda C. S. Gundersen; R. Randall Schumann; James K. Otton; Russell F. Dubiel; Douglass E. Owen; Kendell A. Dickinson


Bulletin | 1991

Field studies of radon in rocks, soils, and water

Linda C. S. Gundersen; Richard B. Wanty

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Ian Jackson

British Geological Survey

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Peter Fox

Rensselaer Polytechnic Institute

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Randy Townsend

American Geophysical Union

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M. Lee Allison

Arizona Geological Survey

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R. Randall Schumann

United States Geological Survey

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Richard B. Wanty

United States Geological Survey

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Deborah L. McGuinness

Rensselaer Polytechnic Institute

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