Nicholas P. Lang

Overcoming Assessment Problems in Google Earth-based Assignments

Abstract Educational technologies such as Google Earth have the potential to increase student learning and participation in geoscience classrooms. However, little has been written about tying the use of such software with effective assessment. To maximize Google Earths learning potential for students, educators need to craft appropriate, research-based objectives, utilize engaging student-centered learning techniques, and directly assess student learning. Several example activities are included to suggest how Google Earth-based geoscience lessons can be created and still maintain measurable learning outcomes.

The magmatic evolution of three Venusian coronae

Abstract The volcanic and tectonic histories of Venusian coronae appear to be intricately linked. We explore that link through the construction of geological maps of three coronae using Magellan synthetic aperture radar (SAR) imagery and altimetry radar data. Each examined corona – Aramaiti, Bhumidevi and Zemire Coronae – is characterized by an annulus of concentric fractures, lava flows, tholi and clusters of small shields. Radial fractures occur at one corona (Bhumidevi Corona), whereas the other two coronae (Aramaiti and Zemire Coronae) occur within linear fracture belts. Based on observed timing relationships, we propose that the evolution of these three coronae is similar to large silicic caldera formation on Earth in that the formation of concentric fractures facilitated a mass evacuation of a magma reservoir residing underneath each corona resulting in subsequent corona collapse. Our model emphasizes the late-stage evolution of these coronae and predicts that all the erupted products could be basaltic. Such predictions are testable through continued geological mapping of coronae, as well as through in situ spectral analyses by Venusian landers.

GEOLOGY OF MEADOW CREEK BASIN, SOUTHERN BLACK MOUNTAINS, ARIZONA: RECORD OF POST-SUPERERUPTION VOLCANISM (REU PROJECT, 2016)

Meadow Creek basin (MCB; southern Black Mountains AZ), 4 km E of the caldera of the 18.8 Ma Peach Spring Tuff (PST) supererupPon (Ferguson et al 2013), reveals a 3 m.y record of the a^ermath of that erupPon. Building on previous work in the area (Ransome 1923, Thorson 1971, LiggeX & Childs 1982; Ferguson pers. com.), NSF-REU undergrads mapped a 12 km2 area within MCB and expanded their spaPal scope through remote sensing (Schwat et al, Helfrich et al, Thompson et al 2016). Students further invesPgated the sequence with opPcal petrography and analysis by XRF, SEM-EDS, and LA-ICPMS.

Volcanic edifice alignment detection software in MATLAB

The scarcity of impact craters on Venus make it difficult to infer the relative ages of geologic units. Stratigraphic methods can be used to help infer the relative ordering of surface features, but the relatively coarse resolution of available radar data means ambiguity about the timing of certain features is common. Here we develop a set of statistical tools in MATLAB to help infer the relative timing between clusters of small shield volcanoes and sets of fractures in the surrounding terrain. Specifically, we employed two variants of the two-point azimuth method to detect anisotropy in the distribution of point-like features. The results of these methods are shown to successfully identify anisotropy at two spatial scales: at the whole-field level and at scales smaller than a set fraction of the mean value. Initial results on the test cases presented here are promising, at least for volcanic fields emplaced under uniform conditions. These methods could also be used for detecting anisotropy in other point-like geologic features, such as hydrothermal vents, springs, and earthquake epicenters. A MATLAB GUI is presented to facilitate use of the two-point azimuth method.No software license purchase is required to run the executable - it is free.The results are shown to successfully identify anisotropy at two spatial scales.These methods could also be used to detect anisotropy in other point-like features.