An Earth Science Scrapbook Project as an Alternative Assessment Tool

"Scrapbooking" is a popular hobby and as such, has found its way into educational settings, primarily in middle and elementary school levels. This article describes a scrapbook project that is used both as a means of demonstrating the connections between geology and students' daily lives and as an alternative form of assessment. The project was developed for an introductory Earth Science class for middle school and high school pre-service teachers. Educational levels: Graduate or professional

Engagement in Authentic Geoscience Research: Evaluation of Research Experiences of Undergraduates and Secondary Teachers

This article examines the effects of a program involving authentic research on the participants' interest in research, career plans, and attitudes on science. The findings are from the first year of a three-year program funded by the National Science Foundation Research Experiences for Undergraduates program. In three out of four projects, participants increased their interest in research, with two-thirds planning to change career plans to become more research-oriented. The implications of these findings for providing authentic research opportunities are discussed. Educational levels: Graduate or professional

A Comparison of Approaches and Instruments for Evaluating a Geological Sciences Research Experiences Program

This article describes a study in which changes in knowledge of science and attitudes regarding science among participants in a summer Research Experiences for Undergraduates (REU) program were examined. It was discovered that existing survey instruments could not detect changes in participants' attitudes over the course of the program and also failed to detect differences between geoscience faculty and a group of college students with limited exposure to college level science. In response to this, researchers developed a new survey instrument based on clusters of statements representing a variety of philosophical positions, from which respondents must pick one statement. It was discovered that open-ended questions about the nature of science provide a potentially richer source of information and that a survey instrument designed to probe more subtle aspects of one's beliefs about science can be used to assess adults who have had a variety of different kinds of exposure to science. The pilot survey instrument may also be able, with modifications, to assess attitude and knowledge changes caused by participation in a scientific research experience. Educational levels: Graduate or professional

Elastic plastic self consistent (EPSC) modeling of plastic deformation in fayalite olivine

We are using an Elastic Plastic Self Consistent Model (a type of numerical simulation) to study deformation of olivine. Olivine is one of the major constituents of the Earth’s upper mantle and its deformation properties have an important influence on how the Earth’s crust deforms. For example, the flow strength of olivine limits the size of the largest earthquakes and the heights of the tallest mountains on Earth. By comparing the results of our simulations with data from olivine deformation experiments we are able to better interpret the experimental data

Initial Acoustoelastic Measurements in Olivine: Investigating the Effect of Stress on P- and S-Wave Velocities

It is well known that elasticity is a key physical property in the determination of the structure and composition of the Earth and provides critical information for the interpretation of seismic data. This study investigates the stress-induced variation in elastic wave velocities, known as the acoustoelastic effect, in San Carlos olivine. A recently developed experimental ultrasonic acoustic system, the Directly Integrated Acoustic System Combined with Pressure Experiments (DIASCoPE), was used with the D-DIA multi-anvil apparatus to transmit ultrasonic sound waves and collect the reflections. We use the DIASCoPE to obtain longitudinal (P) and shear (S) elastic wave velocities from San Carlos olivine at pressures ranging from 3.2–10.5 GPa and temperatures from 450–950°C which we compare to the stress state in the D-DIA derived from synchrotron X-ray diffraction. We use elastic-plastic self-consistent (EPSC) numerical modeling to forward model X-ray diffraction data collected in D-DIA experiments to obtain the macroscopic stress on our sample. We can observe the relationship between the relative elastic wave velocity change (ΔV/V) and macroscopic stress to determine the acoustoelastic constants, and interpret our observations using the linearized first-order equation based on the model proposed by Hughes and Kelly (1953), https://doi.org/10.1103/physrev.92.1145. This work supports the presence of the acoustoelastic effect in San Carlos olivine, which can be measured as a function of pressure and temperature. This study will aid in our understanding of the acoustoelastic effect and provide a new experimental technique to measure the stress state in elastically deformed geologic materials at high pressure conditions

Connecting Aerial Gamma Ray Surveys and Geochemical Data

Radiation in the Environment Aerial Gamma Ray Surveys Radiation and Geology Collecting Existing Geochemical Data Rock Unit Geochemistry Model Creation and Compariso

Elastic Plastic Self-Consistency (EPSC) Modeling on Quartz Deformation Experiments

Our understanding of the rheology of Earth’s interior can be advanced by investigating the results of high-pressure deformation experiments on polycrystalline samples using elastic-plastic self-consistency (EPSC) modeling. Our experiment investigates quartz, which dominates Earth’s crustal composition and is least resistant to flow during deformation thus its bulk strength is thought to control the strength of the crust. During deformation experiments, a polycrystalline sample is enveloped in a cube-shaped sample assembly which is pressurized by a surrounding multi-anvil press known as a D-DIA apparatus. The D-DIA consists of six tungsten carbide anvils, driven by a hydraulic press that moves the top and bottom anvils independently. The sample is monitored by a high-powered x-ray beam at the Argonne National Lab. X-rays record changes in the distances between crystal lattice planes (d-spacing). Our results and those produced by other investigators show local stress is not homogeneous throughout a polycrystalline sample but varies greatly throughout grain populations. EPSC modeling simulates the anisotropic response of individual grains under load with respect to orientation, boundary conditions, and grain populations to best fit our diffraction data. Our samples reached temperatures ranging from 400 to 840 ℃ and pressures of 1.4 to 2.7 GPa. Lattice reflection spectra on the (101), (110), (200), (201), and (112) were gathered incrementally at sample stains nearing 7%. The lattice strain on these reflections is used along with the EPSC models to derive the bulk strength of the material and which slip systems are operating.https://digitalscholarship.unlv.edu/durep_posters/1042/thumbnail.jp

In-situ synchrotron x-ray diffraction study of quartz deformation using the D-DIA apparatus

Deformation is a rock’s mechanical response to external parameters such as temperature and pressure. Knowledge of deformation is necessary to understand geodynamic processes. The behavior of rocks and minerals during deformation depends on the behavior of individual grains within those minerals as they interact. The mineral we are studying is quartz, which we chose since it is very well studied and is highly abundant. We use high-pressure high temperature experiments to simulate conditions of Earth’s interior and the D-DIA apparatus combined with synchrotron x-ray diffraction allows us to record data directly during the process of deformation. The data we collect is used to determine the macroscopic sample stress and tells us also how individual grains react to that stress depending on their orientation within the minera