September 2018 Student Night
Poster Session by CSS Members and Short Talks by Students
CSS Meeting Announcement, Sept-20-2018 (PDF)
For abstracts of the poster presentations and talks see:
CSS Mtg. Sept-
20-2018 Abstracts of Posters and Oral Presentations (PDF)
Oral presentations:
The effects of geological structure and clay on landslides in the Teklanika Formation in Denali National Park and Preserve, Alaska,
Michael Frothingham, PhD student, CU Boulder
Abstract: The dramatic landscape of Denali National Park and Preserve is sculpted by extreme geological forces of uplift and erosion along a major plate boundary. Visitors to the park have the unique opportunity to witness these forces as they occur while scientists, engineers, and staff are tasked with understanding and mitigating the geological hazards associated with them. In response to the many landslides present along the park road corridor, this project identifies, characterizes, and maps the clay and geological structures that are associated with landslides between miles 31 to 53 along the park road.
Clay occurs within the Paleocene Teklanika Formation as an alteration product in moderately continuous stratigraphic horizons of tuff, perlite, and rhyolite that are traceable across structural geometries. Landslides also contain this clay, which is mixed in with debris. Major landslides often occur where the following conditions unique to the Teklanika Formation are met: (1) erosion occurs along a weak horizon of clay, (2) topography above clay horizon is steepened, (3) large colluvium piles are accumulated near the clay horizon, and (4) detrital clay is mixed in with colluvium. Following these conditions, landslides are triggered when the critical shear stress of clay-rich debris is achieved by hydration and weakening of clays, degradation of permafrost or seasonal frost, overloading, or debuttressing.
Newly-identified geological controls suggest increased landslide probability where the basal tuff and clay horizon marks the contact of Teklanika and Cantwell formations, and where steeply-dipping perlite and clay horizons intersect faults or sharp topographic relief. Using the geologic map of clay occurrence, stratigraphy, and structure with reference to landslide conditions listed above, this project illuminates the cause of past and present landslides, and can be used to predict and mitigate future geological hazards.
Insight into incipient motion of blocks on a river bed from Computation Fluid Dynamics modeling,
Aaron Hurst, PhD student, CU Boulder
Abstract: Erosion of bedrock river channels is an important driver of landscape evolution, as it governs the baselevel lowering rate of adjacent hillslopes in mountainous landscapes. In many settings, the upstream migration of bedrock steps or small knickpoints accomplishes most of the vertical erosion in bedrock channels. However, as most models of channel evolution focus on abrasion without accounting for the entrainment of blocks at the downstream edges of bed steps, the magnitude of channel erosion and the detailed geometry of bedrock channels are not well captured. In order to quantitatively capture the role of channel erosion by block entrainment, or plucking, in future models, we first require insight into the physics of incipient motion of blocks on a bedrock channel bed. To date, all of the theory and experiments that inform plucking models are based upon force balances on individual blocks (i.e., Dubinski and Wohl, 2013; Lamb, 2015) with limited application to larger scale models of landscape evolution (i.e., Shobe et al., 2017; Larsen et al., 2016). A significant hurdle in predicting block entrainment by plucking is the lack of sufficient data to defend the choice of a drag coefficient that informs block entrainment thresholds in these force balances. We currently lack consistent predictions of the proper drag coefficient necessary to estimate the drag force, and lack constraints on the magnitudes of pressures to which the vertical edges of a block are subjected in a given flow. We hypothesize that short temporal scale fluctuations in the water pressure in the recirculation zone downstream of a block in open channel turbulent flow greatly influences the magnitude of the drag force acting on the block, and thus values of drag coefficients and pressure differences that should be used in calculation of the force balances. These recirculation zone lengths reflect a combination of block and upstream step geometries and turbulent fluctuations in the flow. We use Computation Fluid Dynamics (CFD) experiments to test the effects of block and step geometries on drag coefficients in order to estimate the range of drag coefficients to be expected for given block aspect ratios and protrusion heights that are found in natural streams. We then use these constraints to develop a relationship between drag, channel geometry, and block geometry that will place future channel evolution models on firm physics-based ground.
Seasonality of a Sub-Alpine Lake: Understanding evolving physical and biogeochemical controls on aquatic ecosystem structure under ice cover. Rocky Mountain National Park, Colorado USA,
Garrett Rue, PhD Candidate, CU Boulder
Abstract: In mountainous regions such as Colorado’s Front Range, changes in hydroclimatology and enhanced exogenous input of nitrogen from atmospheric deposition, are driving changes in lake ecosystems. While summer is an important period when primary production dominates lake ecosystem structure and function, less is known about how these trophodynamics change during the longer period of winter ice-cover. Ongoing research of Bear Lake, located in the sub-alpine of Rocky Mountain National Park, Colorado, USA has shown that depth profiles of dissolved oxygen change in the lake due to variation of snow cover on the ice. Preferential deposition of snow on the east side of the lake driven by wind creates a shallower depth to the oxycline by limiting light penetration through the snow and ice to support photoautotrophs compared to the snow-free west side of the lake. However, concentrations of dissolved organic carbon (DOC) appear consistent across these surface cover conditions and predictably increase by depth. Under the competing role of snow cover influencing primary production near the surface in producing oxygen against heterotrophic processes consuming it at increasing depths, we hypothesize that the developing strata create a redox gradient where dissolved organic matter (DOM) accumulates in a reduced state below the oxycline to essentially act as a battery to store chemical energy. Favoring heterotrophic activity, this further promotes the assimilation of nitrogen into the DOM pool and an evolving reservoir of labile carbon primed to jumpstart the aquatic ecosystem during lake turnover in the spring. We present data collected from Bear Lake throughout the winter of 2018, to better elucidate these shifts in aquatic ecosystem function against physical and chemical conditions. This both advances our understanding of oligotrophic, mountain lake sensitivity to change and predicting response to future pressure, also identifying key biogeochemical processes that may seasonally control microbial and planktonic foodweb structure.
The role of flashing in the formation of high-grade, low-sulfidation epithermal deposits: a case study from the Omu Camp in Hokkaido, Japan,
Lauren Zeeck, MS Candidate, Colorado School of Mines
Abstract: The Miocene low-sulfidation epithermal Hokuryu and Omui deposits of the Omu camp in northeastern Hokkaido, Japan, are small past-producers of high-grade Au and Ag ores. The quartz textures of high-grade ore samples and the distribution of ore minerals within crustiform banded and brecciated quartz veins were studied to identify the processes that resulted in the bonanza-grade precious metal enrichment in these deposits. Correlative microscopy involving optical microscopy, cathodoluminescence microscopy, and scanning electron microscopy was employed in the study of quartz textures and the ore minerals. The research shows that quartz occurring in the quartz veins exhibits a wide range of textures that represent primary growth patterns. In addition, textures indicative of recrystallization of silica precursor phases and replacement of other vein minerals were recognized. In the high-grade vein samples, which are crustiform or brecciated in hand specimen, ore minerals almost exclusively occur within distinct dark gray to black quartz bands. These bands alternate with barren, white to light gray quartz suggesting that ore deposition was episodic during the formation of the low-sulfidation epithermal veins. The dark gray to black quartz bands hosting the ore minerals are colloform and are composed of mosaic quartz. High-magnification microscopy reveals the presence of densely packed relic microspheres providing evidence that the mosaic quartz hosting the ore minerals formed through recrystallization of a non-crystalline silica precursor phase. The ore minerals occur interstitially to the densely packed microspheres or form dendrites within a framework of microspheres indicating that ore deposition was contemporaneous to the agglomeration of the microspheres. These colloform bands with relic microsphere textures are interpreted to have formed through rapid silica and ore mineral deposition within the veins at high temperatures, presumably involving temporary flashing of the hydrothermal system. Limited fluid inclusion data suggest that silica deposition occurred at a temperature of over 245-250°C implying that flashing occurred to a depth of over 400 m below the paleosurface. The ore-hosting colloform bands composed of agglomerated microspheres are texturally distinct from barren, colloform bands containing fibrous chalcedonic quartz bands formed at lower temperatures. The findings of this study are consistent with models linking the high-grade precious metal enrichment in lowsulfidation epithermal veins to episodic flashing of the hydrothermal system in the near-surface environment and have significant implications to the design of exploration strategies for bonanza-grade low sulfidation epithermal vein deposits.
Past Student Nights
2017 Student Night
CSS September 21st Meeting, Student Presentations
Colorado students previewed their cutting-edge research prior to the 2016-2017 conference season.
WHEN: Thursday, September 21, 2017
5:45-6:45 PM, Happy Hour and Poster Session
6:45-8:30 PM, Student Papers Presented
8:30-9:00 PM, Take down and cleanup. We must be out by 9:00
WHERE: The Arbor House, Maple Grove Park (Applewood area)
14600 W 32nd Ave., Golden CO 80401
Map
DETAILS: Light snacks provided.
STUDENTS: Great opportunity to network and present your research! The talk voted best in show wins $250!! Other speakers will be reimbursed travel costs. Recycled posters are acceptable too.
PRESENTATIONS: The oral talks were 15 minutes each, 12 minutes for the presentation and 3 minutes for questions, as at professional meetings.
Kelly Kochanski, CU Geological Sciences Department, “The self-organization of snow surfaces and the growth of sastrugi”
Jenny Nakai, CU Geological Sciences Department (Geophysics), “A possible causative mechanism of Raton Basin, New Mexico and Colorado earthquakes using recent seismicity patterns and pore pressure modeling”
Simon Pendleton, CU Geological Sciences Department, “Testing the ice cover history of preserved landscapes on Baffin Island using 14C”
Jessica Roberts, CU Astrophysical and Planetary Science Department, “The atmospheres of two super-puffy exoplanets”
John Waida, MSU Earth and Atmospheric Sciences Department, “Feasibility of fluorescent placer diamond prospecting using ultra-violet specific longwave LED light sources”
Yalin Li, CSM Civil and Environmental Engineering, “Transformation of Wastewater Treatment- Energy and Nutrient Recovery from Municipal Wastewater”
DETAILS:
We had complimentary light refreshments at the meeting, including a pony keg from the Golden City Brewery. If you plan to drink, please bring an ID “if you could in the remotest way be construed to be under 21”.
There was a popular vote among all attending to decide on “the best oral presentation of the evening”, and the winning student will receive a $250 prize.
The “best presentation” award went to Kelly Kochanski for her talk, “The self-organization of snow surfaces and the growth of sastrugi”.
Download the event flyer:
Colo Sci Soc September 21st Meeting – Student Papers and Posters
2016 Student Night
September 15th, 2016 Meeting
Student Paper Night
Held at the Arbor House, Maple Grove Park
Thursday, September 15, 2016, 5:45-9:00 p.m.
Arbor House, Maple Grove Park (Applewood area)
14600 W 32nd Ave., Golden CO 80401
Map
All are welcome – no admission charge
Social Hour starts at 5:45, meeting at 7:00
Colorado students will preview their cutting-edge research prior to the upcoming 2016-2017 conference season.
Get the scoop here first!! Happy hour and poster social followed by six 15-min lectures.
DETAILS: Light snacks provided. BYOB.
STUDENTS: Great opportunity to network and present your research! The talk voted best in show wins $250!! Recycled posters are acceptable too.
The Colorado Scientific Society was founded in 1882 as a forum for the exchange of observations and ideas on the topics of earth science. Our lecture series occurs on the third Thursday of each month, from September through May. Lecture topics largely focus on earth science, and are open to the public. In addition to our monthly lecture series, the society is also active in public service. We fund student research grants, construct and post signs that describe local geologic features, and organize and lead several field trips.
