Geology Commons^™

The Origin Of Xenoliths With Cumulus Textures Found Above The Subsurface Extension Of The Stillwater Complex, Montana, Cassandra K. Hennings, Jennifer A. Thomson, Michael L. Zientek

Geology Student Works

The Archean Stillwater Complex is a large layered mafic-ultramafic intrusion (LMI) exposed in the

Beartooth Mountains of south-central Montana. Gravity measurements suggest that the north-dipping complex extends under cover at depth. Some of the exposures located above the subsurface Stillwater Complex are younger Cretaceous stocks (Susie Peak and Sliderock Mountain stocks), diorite sills and andesite dikes, exposed north of the complex, passed through area of the gravity anomaly that may be the Stillwater Complex. In the summer of 2013, samples of the stocks and their included xenoliths (foreign rock fragments; commonly metamorphosed to greenschist facies conditions) were collected for study. …

Chitinozoan Biodiversity In The Ordovician Of Gondwana: An Interval-Free Approach Using The Quantitative Stratigraphic Correlation Program Conop9, Rachel Sales

Honors Theses

The purpose of this study is to examine the biodiversity patterns of a group of fossil organisms called chitinozoans. Chitinozoans are organic-walled, planktonic microfossils that first appear in the Early Ordovician Period (488 million years ago) and diversify rapidly through the Paleozoic Era. The Ordovician Period was a time of great global climate change, and by studying this group of fossil plankton, we hope to better understand how modern plankton, which are the base of the marine food chain, might respond to climate change. We used a method called constrained optimization (CONOP9) to construct a composite range chart of 152 …

Active Salt Deformation And Rapid, Transient Incision Along The Colorado River Near Moab, Utah, Andrew P. Jochems, Joel L. Pederson

Geosciences Faculty Publications

In certain settings, erosion is driven by and balanced with tectonic uplift, but the evolution of many landscapes is dominated by other factors such as geologic substrate, drainage history, and transient incision. The Colorado Plateau is an example where these controls are debated and where salt deformation is hypothesized to be locally active and driven by differential unloading, although this is unconfirmed and unquantified in most places. We use luminescence-dated Colorado River terraces upstream of Moab, Utah, to quantify rates of salt-driven subsidence and uplift at the local scale. Active deformation in the study area is also supported by patterns …

Peralkaline Felsic Magmatism At The Nemrut Volcano, Turkey: Impact Of Volcanism On The Evolution Of Lake Van (Anatolia), Ray Macdonald, Mari Sumita, Hans-Ulrich Schmincke, Boguslaw Baginski, John C. White, Slawomir S. Ilnicki

EKU Faculty and Staff Scholarship

Nemrut volcano, adjacent to Lake Van (Turkey), is one of the most important peralkaline silicic centres in the world, where magmatism for ~570,000 years has been dominated by peralkaline trachytes and rhyolites. Using onshore and Lake Van drill site tephra samples, we document the phenocryst and glass matrix compositions, confirming a complete spectrum from very rare mafic to dominantly silicic magmas. Magma mixing has been common and, along with the multi-lineage nature of the magmas, indicates that Nemrut has been a very open system where, nevertheless, compositionally zoned caps developed during periods of relative eruptive quiescence. Geothermometry suggests that the …

Temporal Variations Of Atmospheric Depositional Fluxes Of 7be And 210pb Over 8 Years (2006–2013) At Shanghai, China, And Synthesis Of Global Fallout Data, Juan Du, Jinzhou Du, Mark Baskaran, Qianqian Bi, Dekun Huang, Yifei Jiang

Environmental Science and Geology Faculty Research Publications

7Be and 210Pb, two atmospherically delivered radionuclides, have been broadly applied to study the processes including air mass transport, soil erosion, and particle cycling in aqueous systems. These studies require temporal variations of their depositional fluxes. In the present work, monthly atmospheric bulk depositional fluxes of 7Be and 210Pb were measured over 8 years (December 2005 to December 2013) at Shanghai, China. The bulk depositional fluxes of 7Be and 210Pb varied from 17.9 to 421 Bq m−2 month−1 and 6.8 to 82.1 Bq m−2 month−1, respectively. The volume‐weighted activities ranged from 0.20 to 8.06 Bq L−1 for 7Be and 0.05 …

Geomorphology: Changing The Scholarly Sources Landscape With Geology Students, Heidi Blackburn, Ashlee L. Dere

Criss Library Faculty Proceedings & Presentations

Find out how we changed the landscape for geology students from a popular sources wasteland to a lush garden of scholarly sources through a library instruction intervention. Data from before and after the library instruction will be shared, showing student growth from Wikipedia in first drafts to meeting ACRL Information Literacy Standards for Science through the use of scholarly sources in the final paper. The library instruction activity, learning outcomes, and assessment components are included.

Morphodynamics Of Mullet Key, West-Central Florida, Emeli Sandoval

USF Tampa Graduate Theses and Dissertations

Mullet Key is a right angle barrier island located at the mouth of Tampa Bay, west-central Florida. Based on historical shoreline data from 1873, the Gulf (west)-facing section of the beach has been dynamic illustrating large beach advances and retreats of up to 500 m on a decadal scale, while the south (channel)-facing section of the beach has shown to maintain a stable shoreline. This study focuses on the morphodynamics of the Gulf-facing beach. Since the 1920s, most of the Gulf-facing beach has been accreting except at the southern end near the Tampa Bay main channel. However, over the past …

The Speleogenesis Of Vallgornera Cave (Mallorca, Spain): A Mineralogical And Morphological Study, Jacqueline Amelia Diehl

USF Tampa Graduate Theses and Dissertations

Cova des Pas de Vallgornera (CPV) is morphologically and scientifically, the most prominent karst feature of Mallorca Island (Spain). It consists of over 74 km of passages developed within two carbonate lithologies (reef front and back reef facies) of Upper Miocene age. Two distinct cave patterns are recognized, both tightly controlled by the type of facies; spongework mazes and collapse chambers are characteristic for the reef front unit, whereas linear, fracture-guided galleries develop in the back reef carbonates. CPV is abundantly decorated with a variety of speleothems.

The overarching goal of this study is to provide evidence towards the cave's …

Natural And Anthropogenic Processes Contributing To Metal Enrichment In Surface Soils Of Central Pennsylvania, A. M.L. Kraepiel, Ashlee L.D. Dere, E. M. Herndon, Susan L. Brantley

Geography and Geology Faculty Publications

Metals in soils may positively or negatively affect plants as well as soil micro-organisms and mesofauna, depending on their abundance and bioavailability. Atmospheric deposition and biological uplift commonly result in metal enrichment in surface soils, but the relative importance of these processes is not always resolved. Here, we used an integrated approach to study the cycling of phosphorus and a suite of metals from the soil to the canopy (and back) in a temperate watershed. The behavior of elements in these surface soils fell into three categories. First, Al, Fe, V, Co, and Cr showed little to no enrichment in …

Fossils Of Putative Marine Algae From The Cryogenian Glacial Interlude Of Mongolia, Phoebe A. Cohen, Francis A. Macdonald, Sara Pruss, Emily Matys, Tanja Bosak

Geosciences: Faculty Publications

Neoproterozoic carbonate successions provide a new taphonomic window into the diversification of eukaryotes. We report recently discovered macroscopic organic warty sheets (MOWS) in macerates of limestone from the ca. 662-635 Ma Taishir Formation (Tsagaan Olom Group, Mongolia). Sheets are applanate. One surface contains raised ridges and conspicuous, ∼ 100-μm-tall warty protuberances with depressed tops that enclose internal cavities containing cellular structures. The Taishir MOWS may be the remains of unusual bacterial, protistan, or fungal biofilms, or a previously undocumented, extinct taxon. However, multiple lines of evidence including the morphology of warty protuberances and the presence of cellular architecture within protuberances …

Core Evolution Driven By Mantle Global Circulation, Peter Olson, Renaud Deguen, Maxwell L. Rudolph, Shijie Zhong

Geology Faculty Publications and Presentations

Reconstructions of the Phanerozoic history of mantle global circulation that include past plate motions are used to constrain the thermochemical evolution of the core. According to our mantle global circulation models, the present-day global average heat flux at the core-mantle boundary lies in the range 80-90 mW.m^-2, with peak-to-peak, long wavelength lateral variations up to 100 mW.m^-2 associated with compositional and thermal heterogeneity in the D”-layer. For core thermal conductivity in the range k=100-130 W.m^-1.K^-1 we infer that the present-day outer core is thermally unstable beneath the high seismic velocity regions in the …

Dissolved Fe And Al In The Upper 1000 M Of The Eastern Indian Ocean: A High‐Resolution Transect Along 95°E From The Antarctic Margin To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, William Landing, Peter Morton, Clifton Buck, Pamela Barrett, Joseph Resing

Faculty Publications

A high‐resolution section of dissolved iron (dFe) and aluminum (dAl) was obtained along ~95°E in the upper 1000 m of the eastern Indian Ocean from the Antarctic margin (66°S) to the Bay of Bengal (18°N) during the U.S. Climate Variability and Predictability (CLIVAR) CO2 Repeat Hydrography I08S and I09N sections (February–April 2007). In the Southern Ocean, low concentrations of dAl (<1 n M) reflect the negligible dust inputs impacting the water masses subducted in the circumpolar domain. The low dAl concentrations characterizing the Southern Ocean terminate near 45°S, probably because of the advection of subtropical water masses that received dust and sedimentary inputs in their formation region. Our subsurface dFe data near the southern Kerguelen Plateau were significantly higher than historical observations in other Indian sectors of the Southern Ocean. We surmise that the offshore advection of dFe‐rich waters along the western flank of the southern Kerguelen plateau and enhanced vertical mixing could contribute to this elevated subsurface dFe inventory. Elevated subsurface particulate and dFe levels downstream of the northern Kerguelen Plateau may reflect long‐range lateral transport from the plateau's sediments and/or remineralization inputs. At the northern edge of the south Indian subtropical gyre, the deposition of Australian dust, possibly combined with the advection of dAl‐enriched waters from the Indonesian Throughflow, creates a region of elevated dAl in the upper 400 m but without a corresponding enrichment in dFe. In the northern Indian Ocean, the South Equatorial Current constitutes a remarkable biogeochemical front separating the oxygen‐rich and dFe‐poor subtropical gyre waters from the dFe‐rich and oxygen‐depleted waters of the northern Indian Ocean. By tracing the accumulation of macronutrients and dFe along the advective pathway of Indian Central Water, we show that the central waters of the northern Indian Ocean receive excess dFe in addition to that produced by remineralization inputs. The resuspension of shelf sediments and release of pore waters probably contribute to the elevated dFe and dAl levels observed below the highly stratified upper layers of the Bay of Bengal.

Dust Deposition In The Eastern Indian Ocean: The Ocean Perspective From Antarctica To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, Clifton Buck, William Landing

Faculty Publications

Atmospheric deposition is an important but still poorly constrained source of trace micronutrients to the open ocean because of the dearth of in situ measurements of total deposition (i.e., wet + dry deposition) in remote regions. In this work, we discuss the upper ocean distribution of dissolved Fe and Al in the eastern Indian Ocean along a 95°E meridional transect spanning the Antarctic margin to the Bay of Bengal. We use the mixed layer concentration of dissolved Al in conjunction with empirical data in a simple steady state model to produce 75 estimates of total dust deposition that we compare …

Strain Accomodation In The Footwall Of The Rubys Inn Thrust Fault, Hillsdale Canyon, Southern Utah, Claire Cleveland, Rhiannon M. Garrard, Devin M. Mclemore, Jeff C.E. Yon, Genevieve Kidman, John S. Maclean

The Compass: Earth Science Journal of Sigma Gamma Epsilon

The Rubys Inn thrust fault in southern Utah has produced several styles of deformation in its footwall. This project describes four exceptionally well exposed examples of strain accommodation, including a mountain-scale, ductile footwall drag fold, cataclastic flexural slip between bedding surfaces of differing competencies, plastically deformed petrified wood within the zone of flexural slip, and cataclastic shear expressed as deformation bands. Such examples show how various lithologies can be deformed into a wide array of structures during a single deformation event. Furthermore, some of these structures result in changes in permeability, which are important for those interested in subsurface fluid …

Karst Porosity Estimations From Archive Cave Surveys - Studies In The Buda Thermal Karst System (Hungary), Gáspár Albert, Magdolna Virág, Anita Erőss

International Journal of Speleology

The Buda Thermal Karst System is located under the densely populated hills of Budapest. One of its caves (Pál-völgy Cave System) is the longest cave of Hungary with 30.1 km. The research was done in this area as a methodological study to estimate karst porosity parameters of aquifers or hydrocarbon reservoirs. In this study two modeling methods are demonstrated. The volumetric modeling method was primarily aimed to determine the macro-scale (>0.5 m) conduit porosity (referred as macroporosity) of the study area as percentage of the incorporating limestone and marl. This method is based on archive survey data (maps and …

Beyond The Angle Of Repose: A Review And Synthesis Of Landslide Processes In Response To Rapid Uplift, Eel River, Northern Eel River, Northern California, Joshua J. Roering, Benjamin H. Mackey, Alexander L. Handwerger, Adam M. Booth, David A. Schmidt, Georgina L. Bennett, Corina Cerovski-Darriau

Geology Faculty Publications and Presentations

In mountainous settings, increases in rock uplift are often followed by a commensurate uptick in denudation as rivers incise and steepen hillslopes, making them increasingly prone to landsliding as slope angles approach a limiting value. For decades, the threshold slope model has been invoked to account for landslide-driven increases in sediment flux that limit topographic relief, but the manner by which slope failures organize themselves spatially and temporally in order for erosion to keep pace with rock uplift has not been well documented. Here, we review past work and present new findings from remote sensing, cosmogenic adionuclides, suspended sediment records, …

Bubble Mobility In Mud And Magmatic Volcanoes, Aaron Tran, Maxwell L. Rudolph, Michael Manga

Geology Faculty Publications and Presentations

The rheology of particle-laden fluids with a yield stress, such as mud or crystal-rich magmas, controls the mobility of bubbles, both the size needed to overcome the yield stress and their rise speed. We experimentally measured the velocities of bubbles and rigid spheres in mud sampled from the Davis-Schrimpf mud volcanoes adjacent to the Salton Sea, Southern California. Combined with previous measurements in the polymer gel Carbopol, we obtained an empirical model for the drag coefficient and bounded the conditions under which bubbles overcome the yield stress. Yield stresses typical of mud and basaltic magmas with sub-mm particles can immobilize …

Current State Of Strain In The Central Cascadia Margin Derived From Changes In Distance Between Gps Stations, Kenneth M. Cruikshank, Curt D. Peterson

Geology Faculty Publications and Presentations

Using continuously operating Global Positioning Stations in the Pacific Northwest of the United States, over 100 station-station baseline length changes were determined along seven West-East transects, two North-South transects and in three localized areas to determine both the average annual strains over the past several years, and the variation in strain over the central Cascadia convergent margin. The North-South transects (composed of multiple baselines) show shortening. Along West-East transects some baselines show shortening and others extension. The direction of the principle strains calculated for two areas 100 km from the deformation front are close to per-pendicular to the deformation front. …

Thermal Perturbations Beneath The Incipient Okavango Rift Zone, Northwest Botswana, Khumo Leseane, Estella A. Atekwana, Kevin Lee Mickus, Mohamed G. Abdel Salam, Elisha M. Shemang, Eliot A. Atekwana

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

We used aeromagnetic and gravity data to investigate the thermal structure beneath the incipient Okavango Rift Zone (ORZ) in northwestern Botswana in order to understand its role in strain localization during rift initiation. We used three-dimensional (3-D) inversion of aeromagnetic data to estimate the Curie Point Depth (CPD) and heat flow under the rift and surrounding basement. We also used two-dimensional (2-D) power-density spectrum analysis of gravity data to estimate the Moho depth. Our results reveal shallow CPD values (8-15 km) and high heat flow (60-90 mW m^-2) beneath a ∼60 km wide NE-trending zone coincident with major …

A Systematic Comparison Of The Transverse Energy Minimization And Splitting Intensity Techniques For Measuring Shear-Wave Splitting Parameters, Fansheng Kong, Stephen S. Gao, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Over the past several decades, shear-wave splitting (SWS) analyses have been increasingly utilized to delineate mantle structure and probe mantle dynamics. However, the reported splitting parameters (fast polarization orientations and splitting times) are frequently inconsistent among different studies, partially due to the different techniques used to estimate the splitting parameters. Here, we report results from a systematic comparison of the transverse minimization (TM) and the splitting intensity (SI) techniques. The study was motivated by the fact that recent comparative studies led to conflicting conclusions, which include the suggestion that TM, which is arguably the most widely used SWS-measuring technique, performs …

Glacier Status And Contribution To Streamflow In The Olympic Mountains, Usa, Jon L. Riedel, Steve Wilson, William Baccus, Michael Larrabee, T.J. Fudge, Andrew G. Fountain

Geology Faculty Publications and Presentations

The Olympic Peninsula, Washington, USA, currently holds 184 alpine glaciers larger than 0.01 km² and their combined area is 30.2 ± 0.95km². Only four glaciers are >1km² and 120 of the others are -¹ (1900–80) to 0.54 km² a^-¹ (1980–2009). Thinning rates on four of the largest glaciers averaged nearly 1ma^-¹ from 1987 to 2010, resulting in estimated volume losses of 17–24%. Combined glacial snow, firn and ice melt in the Hoh watershed is in the range 63–79 ± 7 × 10⁶m³, or 9–15% of total May–September streamflow. In the critical August–September …

Validity Of Holocene Analogs For Ancient Carbonate Stratigraphic Successions: Insights From A Heterogeneous Pleistocene Carbonate Platform Deposit, Colby Hazard

Theses and Dissertations

Observations of modern carbonate depositional environments and their accompanying depositional models have been used for decades in the reconstruction and interpretation of ancient carbonate depositional environments and stratigraphic successions. While these Holocene models are necessary for interpreting their more ancient counterparts, they inherently exclude important factors related to the erosion, diagenesis, and ultimate preservation of sediments and sedimentary structures that are ubiquitous in shallow marine carbonate environments. Andros Island, Bahamas is an ideal location to examine the validity of Holocene conceptual models, where geologically young (Late Pleistocene) limestones can be studied immediately adjacent to their well-documented modern equivalents. For this …

Towards Understanding The Dynamical Evolution Of Asteroid 25143 Itokawa: Constraints From Sample Analysis, Harold Connolly Jr., Dante S. Lauretta, Kevin J. Walsh, Shogo Tachibana, William F. Bottke Jr.

School of Earth & Environment Departmental Research

The data from the analysis of samples returned by Hayabusa from asteroid 25143 Itokawa are used to constrain the preaccretion history, the geological activity that occurred after accretion, and the dynamical history of the asteroid from the main belt to near-Earth space. We synthesize existing data to pose hypotheses to be tested by dynamical modeling and the analyses of future samples returned by Hayabusa 2 and OSIRIS-REx. Specifically, we argue that the Yarkosky-O’Keefe-Radzievskii-Paddack (YORP) effect may be responsible for producing geologically high-energy environments on Itokawa and other asteroids that process regolith and essentially affect regolith gardening.

Pleistocene Relative Sea Levels In The Chesapeake Bay Region And Their Implications For The Next Century, Benjamin D. Dejong, Paul R. Bierman, Wayne L. Newell, Tammy M. Rittenour, Shannon A. Mahan, Greg Balco, Dylan H. Rood

Geosciences Faculty Publications

Today, relative sea-level rise (3.4 mm/yr) is faster in the Chesapeake Bay region than any other location on the Atlantic coast of North America, and twice the global average eustatic rate (1.7 mm/yr). Dated interglacial deposits suggest that relative sea levels in the Chesapeake Bay region deviate from global trends over a range of timescales. Glacio-isostatic adjustment of the land surface from loading and unloading of continental ice is likely responsible for these deviations, but our understanding of the scale and timeframe over which isostatic response operates in this region remains incomplete because dated sea-level proxies are mostly limited to …

Biotic Controls On Solute Distribution And Transport In Headwater Catchments, E. M. Herndon, Ashlee L.D. Dere, P. L. Sullivan, D. Norris, B. Reynolds, Susan L. Brantley

Geography and Geology Faculty Publications

Solute concentrations in stream water vary with discharge in patterns that record complex feedbacks between hydrologic and biogeochemical processes. In a comparison of headwater catchments underlain by shale in Pennsylvania, USA (Shale Hills) 5 and Wales, UK (Plynlimon), dissimilar concentration-discharge behaviors are best explained by contrasting landscape distributions of soil solution chemistry – especially dissolved organic carbon (DOC) – that have been established by patterns of vegetation. Specifically, elements that are concentrated in organic-rich soils due to biotic cycling (Mn, Ca, K) or that form strong complexes with DOC (Fe, Al) are spatially heteroge- 10 neous in pore waters because …

The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence For Hydration And Thermal Upwellings, E. L. Emry, A. A. Nyblade, J. Juliá, S. Anandakrishnan, R. C. Aster, D. A. Wiens, Audrey D. Huerta, T. J. Wilson

All Faculty Scholarship for the College of the Sciences

Although prior work suggests that a mantle plume is associated with Cenozoic rifting and volcanism in West Antarctica, the existence of a plume remains conjectural. Here we use P wave receiver functions (PRFs) from the Antarctic POLENET array to estimate mantle transition zone thickness, which is sensitive to temperature perturbations, throughout previously unstudied parts of West Antarctica. We obtain over 8000 high‐quality PRFs using an iterative, time domain deconvolution method filtered with a Gaussian width of 0.5 and 1.0, corresponding to frequencies less than ∼0.24 and ∼0.48 Hz, respectively. Single‐station and common conversion point stacks, migrated to depth using the …

The Routine Disaster: A Case Study In El Salvador, Tyler M. Barton

Dissertations, Master's Theses and Master's Reports - Open

A 2010 report by the UN Disaster Assessment and Coordination ranked El Salvador as the most vulnerable country in the world to natural disasters, with roughly 95% of the population at risk. The combination of recurring natural disasters and high vulnerability in a relatively small country has led to repeated exposure of local residents to significant natural phenomena of all sorts, including earthquakes, flooding, landslides, volcanic eruptions, and hurricanes.

The effect of disaster assistance can be multi-faceted and this report examines the case of flooding hazards of a small town in the south-eastern San Miguel region of the country, called …

Origin And Quantification Of Diffuse Co2 And H2s Emission At Crater Hills, Yellowstone National Park, Peipei Lin

Dissertations, Master's Theses and Master's Reports - Open

At Crater Hills, a thermally-altered area adjoining the Sour Creek resurgent dome that is located within the Yellowstone Caldera, we characterized volatile emissions based upon our soil degassing measurements and soil gas chemistry in 2014 and fumarole gas chemistry in 2007 (Bergfeld et al., 2011). The investigation at Crater Hills on its diffuse gases isotopes and CO2, H2S emission improve our understanding on its gas emission mode – including total emission and spatial distribution, and contribute to a more accurate estimation of total CO2 emission at Yellowstone volcanic system. The total emission of CO2 interpolated by sequential Gaussian simulation method …

Morphological, Structural, And Spectral Characteristics Of Amorphous Iron Sulfates, Elizabeth Sklute, Heidi Jensen, Deanne Rogers, Richard Reeder

Department of Geosciences Faculty Publications

Current or past brine hydrologic activity on Mars may provide suitable conditions for the formation of amorphous ferric sulfates. Once formed, these phases would likely be stable under current Martian conditions, particularly at low- to mid-latitudes. Therefore, we consider amorphous iron sulfates (AIS) as possible components of Martian surface materials. Laboratory AIS were created through multiple synthesis routes and characterized with total X-ray scattering, thermogravimetric analysis, scanning electron microscopy, visible/near-infrared (VNIR), thermal infrared (TIR), and Mössbauer techniques. We synthesized amorphous ferric sulfates (Fe(III)2(SO4)3 · ~ 6–8H2O) from sulfate-saturated fluids via vacuum dehydration or exposure to low relative humidity (

The Digital Atlas Of Ancient Life: Delivering Information On Paleontology And Biogeography, Jonathan R. Hendricks, Alycia L. Stigall, Bruce S. Lieberman

Faculty Publications

No abstract provided.