Physical Sciences and Mathematics Commons^™

Geol 112: Hazards, Risks Of Earthquakes And Volcanoes Textbook Alternatives, Donald Reed

Donald Reed

Poster summarizing cost saving textbook alternatives for GEOL 112: Hazards, Risks of Earthquakes and Volcanoes.

The Quasi-Static Deformation, Failure, And Fracture Behavior Of Titanium Alloy Gusset Plates Containing Bolt Holes, Therese Hurtuk, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan, Kannan Manigandan, T. Quick

Craig Menzemer

In this article, the influence of bolt holes, specifically their number and layout on strength, deformation, and final fracture behavior of titanium alloy gusset plates under the influence of an external load is presented and discussed. Several plates having differences in both the number and layout of the bolt holes were precision machined and then deformed under quasi-static loading. The specific influence of number of bolt holes and their layout on maximum load-carrying capability and even fracture load was determined. The conjoint influence of bolt number, bolt layout pattern, nature of loading, contribution from local stress concentration, and intrinsic microstructural …

The Sedimentary Flux Of Dissolved Rare Earth Elements To The Ocean, April Abbott, Brian Haley, James Mcmanus, Clare Reimers

James McManus

We determined pore fluid rare earth element (REE) concentrations in near-surface sediments retrieved from the continental margin off Oregon and California (USA). These sites represent shelf-to-slope settings, which lie above, within, and below the oxygen minimum zone of the Northeast Pacific. The sediments are characterized by varying degrees of net iron reduction, with pore fluids from the shelf sites being generally ferruginous, and the slope sediments having less-pronounced iron reduction zones that originate deeper in the sediment package. REE concentrations show maxima in shallow (upper 2–10 cm) subsurface pore fluids across all sites with concentrations that rise more than two …

The Quasi-Static Deformation, Failure, And Fracture Behavior Of Titanium Alloy Gusset Plates Containing Bolt Holes, Therese Hurtuk, Craig Menzemer, Anil Patnaik, Tirumalai Srivatsan, Kannan Manigandan, T. Quick

Anil Patnaik

In this article, the influence of bolt holes, specifically their number and layout on strength, deformation, and final fracture behavior of titanium alloy gusset plates under the influence of an external load is presented and discussed. Several plates having differences in both the number and layout of the bolt holes were precision machined and then deformed under quasi-static loading. The specific influence of number of bolt holes and their layout on maximum load-carrying capability and even fracture load was determined. The conjoint influence of bolt number, bolt layout pattern, nature of loading, contribution from local stress concentration, and intrinsic microstructural …

Geochronology Of Hemphillian-Blancan Aged Strata, Guanajuato, Mexico, And Implications For Timing Of The Great American Biotic Interchange, Bart Kowallis, John Flynn, Clarita Nunez, Oscar Carranza-Castaneda, Wade Miller, Carl Swisher, Everett Lindsay

Bart J Kowallis

We present new geochronologic magnetostratigraphy, fission-track and 40Ar/39Ar radioisotopic dates, biostratigraphy)bdata constraining the age of three separate sequences and a composite section from Guanajuato, Mexico. Those data make this one of the most complete and precisely age-calibrated sequences in North America spanning the Hemphillian/Blancan North American Land Mammal “Age” (NALMA) boundary interval, and the data further constrain the timing and pattern of the Great American Biotic Interchange (GABI). In total, 196 samples (77 sites) were used to construct the magnetic polarity stratigraphies, with eight fission-track analyses and four new 40Ar/39Ar radioisotopic dates. The sections sampled are possibly latest Miocene to …

Contrasting Silicic Magma Series In Miocene-Pliocene Ash Deposits In The San Miguel De Allende Graben, Guanajuato, Mexico, Eric Christiansen, Bart Kowallis, Aaron Adams, Oscar Carranza-Castaneda, Wade Miller

Bart J Kowallis

The San Miguel de Allende graben, Guanajuato, Mexico, contains numerous rhyolitic volcanic ash beds. Electron microprobe and x-ray fluorescence analyses of glass shards from 14 localities, combined with mineralogic, stratigraphic, radiometric, and paleomagnetic data, allow us to correlate the ash beds (and the intervening sedimentary strata and fossils), understand the timing of volcanism, date the age of extension, and better understand the tectonic and volcanic evolution of central Mexico. Our analyses reveal that at least six separate eruptions of rhyolitic ash occurred during the Late Miocene and Pliocene (5-3 Ma) while the San Miguel Allende basin was subsiding. The fallout …

Late Pleistocene Glacial History And Magnetic Chronostratigraphy, Western Adirondack Borderland, New York, Donald Pair

Donald L. Pair

New lines of evidence from the western Adirondack borderland have been employed to assess the style of deglaciation and reconstruct the nature and timing of associated proglacial lacustrine and marine (Champlain Sea) events. Contrasting styles of deglaciation, controlled primarily by water depth, resulted in landfast ice withdrawing gradually on the northern slope of the Adirondacks while actively calving ice, retreating rapidly in the deep water of Lake Iroquois, quickly evacuated the western St. Lawrence Lowland of ice. The extent of ice retreat from the western St. Lawrence Lowland during the life of Lake Iroquois has been estimated on the basis …

Longitudinal Profile And Sediment Mobility As Geomorphic Tools To Interpret The History Of A Fluviokarst Stream System, John Woodside, Eric Peterson, Toby Dogwiler

Eric Wade Peterson

The complex drainage systems within karst settings can result in atypical longitudinal profiles. Features, such as cave entrances, can be expressed as anomalous ‘bumps’ in the longitudinal profile of a stream if downcutting has continued upstream of the area in which the water is pirated to the subsurface. Horn Hollow, a fluviokarst valley located in Carter Caves State Park Resort in northeastern Kentucky, was examined for these types of features. The objectives of this study were to determine if sediment mobility can be used as a proxy for anomalous areas along the profile of the valley and if detailed cross-sections …

Stratigraphy And Porosity Modeling Of Southern Centeral Illinois Chester (Upper Missisippian) Series Sandstones Usng Petrel, Darren Kimple, Eric Peterson, David Malone

Eric Wade Peterson

Identification Of Potential Vertical Gas Migration Pathways Above Gas Storage Reservoirs, Eric Peterson, Lauren Martin, David Malone

Eric Wade Peterson

The Impact Of Host Rock Geochemistry On Bacterial Community Structure In Oligotrophic Cave Environments, Hazel Barton, Nicholas Taylor, Michael Kreate, Austin Springer, Stuart Oehrle, Janet Bertog

Hazel Barton

Despite extremely starved conditions, caves contain surprisingly diverse microbial communities. Our research is geared toward understanding what ecosystems drivers are responsible for this high diversity. To asses the effect of rock fabric and mineralogy, we carried out a comparative geomicrobiology study within Carlsbad Cavern, New Mexico, USA. Samples were collected from two different geologic locations within the cave: WF1 in the Massive Member of the Capitan Formation and sF88 in the calcareous siltstones of the Yates Formation. We examined the organic content at each location using liquid chromatography mass spectroscopy and analyzed microbial community structure using molecular phylogenetic analyses. In …

The Evolution Of Billfish, Andrew Blitman

Andrew Blitman

No abstract provided.

Limits Of Luminescence Dating: An Update Regarding Quartz Of The Southern Alps Of New Zealand And The Olympic Mountains, Washington, Usa, Cianna Wyshnytzky, Tammy Rittenour

Cianna E Wyshnytzky

Late Pleistocene glacial sediments from the South Fork Hoh River valley in the Olympic Mountains, Washington, USA and the Lake Hawea valley in the Southern Alps, New Zealand were dated using optically stimulated luminescence (OSL) on quartz and infrared stimulated luminescence (IRSL) on feldspar sand from 2011-2013. High sediment supply (typical of glacial environments), short transport distances, and sediment newly eroded from bedrock sources were expected to pose problems for luminescence dating in these locations. Samples were collected from a variety of depositional environments and inferred distances from the ice-front to assess how luminescence signals may vary due to these …

Determination Of The Cec In Srs Soils And The Capability Of Epa Model 9081 For Cec Of Acidic Soils, Alexandra Simpson

Alexandra M Simpson

No abstract provided.

Determination Of The Cec In Srs Soils And The Capability Of Epa Model 9081 For Cec Of Acidic Soils, Alexandra Simpson

Alexandra M Simpson

No abstract provided.

Exhumation Of The Southern Sierra Nevada–Eastern Tehachapi Mountains Constrained By Low-Temperature Thermochronology: Implications For The Initiation Of The Garlock Fault, Ann Blythe, N Longinotti

Ann Blythe

New apatite and zircon fission-track and apatite (U-Th)/He data from nine samples collected on a north-south transect across the southern Sierra Nevada–eastern Tehachapi Mountains constrain the cooling and exhumation history over the past ∼70 m.y. The four northernmost samples yielded zircon and apatite fission-track ages of ca. 70 Ma, indicating rapid cooling from ∼250 °C to <60 °C (6–8 km of exhumation) at that time. Four of the five southernmost samples yielded slightly younger zircon fission-track ages (57–46 Ma) and apatite fission-track ages (21–18 Ma); the fifth southern sample (from a lower elevation) yielded an apatite fission-track age of ca. 11 Ma. Eight of the nine samples yielded apatite (U-Th)/He ages; these ranged from 60 to 9 Ma, with the youngest ages from the southernmost samples. Inverse thermal history models developed from the data reveal two major stages of cooling for the area, with an initial major cooling event ending at ca. 70 Ma, followed by 50 m.y. of thermal stasis and a second major cooling event beginning at 20 Ma and continuing to the present. The data are consistent with northward-directed tilting and exhumation beginning at 20 Ma, probably as the result of north-south extension in the Mojave Desert on an early strand of the Garlock fault with down-to-the-south offset. A third minor phase of rapid exhumation beginning at ca. 10 Ma is suggested by the data; this may indicate the beginning of left-lateral slip on the Garlock fault.

Meteoric 10Be, FeD, And Clay In Critical Zone Soils, Front Range, Colorado, Cianna Wyshnytzky, James Mccarthy

Cianna E Wyshnytzky

The critical zone is the zone within which meteoric water, atmospheric gases, soil, and bedrock interact, encompassing the zone of soil formation (Anderson et al., 2007). The concentrations of various pedogenic compounds at a given location indicate the degree of weathering that has taken place in the Critical Zone. Among the products of chemical weathering are secondary phyllosilicate minerals (clays) and iron (Birkeland, 1999). At stable sites, chronosequence studies have shown that the amount of pedogenic iron oxide and clay increase as soils become older (McFadden and Hendricks, 1985).

Meteoric ¹⁰Be is a cosmogenic nuclide produced from oxygen and nitrogen …

Holocene Sediment Distribution On The Inner Continental Shelf Of Northeastern South Carolina: Implications For The Regional Sediment Budget And Long-Term Shoreline Response, Jenny Denny, William Schwab, Wayne Baldwain, Walter Barnhadt, Paul Gayes, Robert Morton, John Warner, Neil Driscoll, George Voulgaris

George Voulgaris

High-resolution geophysical and sediment sampling surveys were conducted offshore of the Grand Strand, South Carolina to define the shallow geologic framework of the inner shelf. Results are used to identify and map Holocene sediment deposits, infer sediment transport pathways, and discuss implications for the regional coastal sediment budget.

The thickest deposits of Holocene sediment observed on the inner shelf form shoal complexes composed of moderately sorted fine sand, which are primarily located offshore of modern tidal inlets. These shoal deposits contain ∼67 M m3 of sediment, approximately 96% of Holocene sediment stored on the inner shelf. Due to the lack …

The Magnitude, Timing And Abruptness Of Changes In North African Dust Deposition Over The Last 20,000 Years, D. Mcgee, P. Demenocal, G. Winckler, J. Stuut, Louisa Bradtmiller

Louisa I. Bradtmiller

No abstract provided.

The “Curse Of Rafinesquina:” Negative Taphonomic Feedback Exerted By Strophomenid Shells On Storm-Buried Lingulids In The Cincinnatian Series (Katian, Ordovician) Of Ohio, Rebecca Freeman, Benjamin Dattilo, Aaron Morse, Michael Blair, Steve Felton, John Pojeta

Benjamin F. Dattilo

Taphonomic feedback is the idea that accumulation of organic remains either enhances the habitat for some organisms (positive taphonomic feedback), and/or degrades the habitat for others (negative taphonomic feedback). Examples of epibionts living on skeletal remains are direct evidence of positive taphonomic feedback. Disruption of infaunal burrowing activities by skeletal fragments is an example of negative taphonomic feedback; direct fossil evidence of this phenomenon has not been documented previously. Infaunal organisms are vulnerable to exhumation or entombment during storms, but organisms that burrow can also re-establish viable life positions subsequently. For example, when modern lingulids re-burrow after exhumation, they first …

Introduction And Tribute, George Voulgaris, Timothy Kana, Jacqueline Mitchell

George Voulgaris

No abstract provided.

Kernel Density Estimation Of Traffic Accidents In A Network Space, Zhixiao Xie, Jun Yan

Dr Jun Yan

A standard planar Kernel Density Estimation (KDE) aims to produce a smooth density surface of spatial point events over a 2-D geographic space. However, the planar KDE may not be suited for characterizing certain point events, such as traffic accidents, which usually occur inside a 1-D linear space, the roadway network. This paper presents a novel network KDE approach to estimating the density of such spatial point events. One key feature of the new approach is that the network space is represented with basic linear units of equal network length, termed lixel (linear pixel), and related network topology. The use …

Dating Of Major Normal Fault Systems Using Thermochronology: An Example From The Raft River Detachment, Basin And Range, Western United States, Michael Wells, Lawrence Snee, Ann Blythe

Ann Blythe

Application of thermochronological techniques to major normal fault systems can resolve the timing of initiation and duration of extension, rates of motion on detachment faults, timing of ductile mylonite formation and passage of rocks through the crystal-plastic to brittle transition, and multiple events of extensional unroofing. Here we determine the above for the top-to-the-east Raft River detachment fault and shear zone by study of spatial gradients in 40Ar/39Ar and fission track cooling ages of footwall rocks and cooling histories and by comparison of cooling histories with deformation temperatures. Mica 40Ar/39Ar cooling ages indicate that extension-related cooling began at ∼25–20 Ma, …

Sharks Of The Devonian, Andrew Blitman

Andrew Blitman

No abstract provided.

Evolution Of The Kangmar Dome, Southern Tibet: Structural, Petrologic, And Thermochronologic Constraints, Jeffrey Lee, Bradley Hacker, William Dinklage, Yu Wang, Phillip Gans, Andrew Calvert, Ann Blythe, William Mcclelland

Ann Blythe

Structural, thermobarometric, and thermochronologic investigations of the Kangmar Dome, southern Tibet, suggest that both extensional and contractional deformational histories are preserved within the dome. The dome is cored by an orthogneiss which is mantled by staurolite + kyanite zone metasedimentary rocks; metamorphic grade dies out up section and is defined by a series of concentric kyanite-in, staurolite-in, garnet-in, and chloritoid-in isograds. Three major deformational events, two older penetrative events and a younger doming event, are preserved. The oldest event, D1, resulted in approximately E-W trending tight to isoclinal folds of bedding with an associated moderately to steeply north dipping axial …

Deformation Of Continental Crust Along A Transform Boundary, Coast Mountains, British Columbia, Scott Bogue, Margaret Rusmore, Karen Dodson, Kenneth Farley, Glenn Woodsworth

Scott Bogue

New structural, paleomagnetic, and apatite (U-Th)/He results from the continental margin inboard of the Queen Charlotte fault (∼54°N) delineate patterns of brittle faulting linked to transform development since ∼50 Ma. In the core of the orogen, ∼250 km from the transform, north striking, dip-slip brittle faults and vertical axis rotation of large crustal domains occurred after ∼50 Ma and before intrusion of mafic dikes at 20 Ma. By 20 Ma, dextral faulting was active in the core of the orogen, but extension had migrated toward the transform, continuing there until <9 Ma. Local tilting in the core of the orogen …

Faculty Spotlight: Mark Sutherland, Mark Sutherland

Mark Sutherland

Interview with Mark J. Sutherland about his earth science teaching career at College of DuPage.

Very Rapid Geomagnetic Field Change Recorded By The Partial Remagnetization Of A Lava Flow, Scott Bogue, Jonathan Glen

Scott Bogue

A new paleomagnetic result from a lava flow with a distinctive, two-part remanence reinforces the controversial hypothesis that geomagnetic change during a polarity reversal can be much faster than normal. The 3.9-m-thick lava (“Flow 20”) is exposed in the Sheep Creek Range (north central Nevada) and was erupted during a reverse-to-normal (R-N) geomagnetic polarity switch at 15.6 Ma. Flow 20 began to acquire a primary thermoremanence while the field was pointing east and down but was soon buried, reheated, and partially-remagnetized in a north-down direction by the 8.2-m-thick flow that succeeded it. A simple conductive cooling calculation shows that the …

Mountain Building Across A Lithospheric Boundary During Arc Construction: The Cretaceous Peninsular Ranges Batholith In The Sierra San Pedro Martir Of Baja California, Mexico, K Schmidt, S Paterson, Ann Blythe, C Kopf

Ann Blythe

The Jura-Cretaceous Peninsular Ranges batholith (PRB) of Southern and Baja California contains a remarkable example of variation in crustal composition and structure across a batholith-parallel lithospheric-scale discontinuity. This lithospheric boundary between western oceanic-floored and eastern continental-floored crust influenced contractional deformation, arc magmatism, and differential exhumation of western and eastern zones in the batholith during its evolution. In the Sierra San Pedro Martir of Baja California, Mexico, a ca. 20 km wide, doubly vergent fan structure occurs across the PRB basement transition that consists of inward-dipping mylonite thrust sheets on the sides of the fan that gradually transition to a steeply-dipping …

Plio-Quaternary Exhumation History Of The Central Nepalese Himalaya: 2. Thermo-Kinematic Model Of Thermochronometer Age Prediction Model, David Whipp Jr, Todd Ehlers, Ann Blythe, Katharine Huntington, Kip Hodges, Douglas Burbank

Ann Blythe

[1] In the Himalaya and other active convergent orogens, linear relationships between thermochronometer sample age and elevation are often used to estimate long-term exhumation rates. In these regions, high-relief topography and nonvertical exhumation pathways may invalidate such one-dimensional (1-D) interpretations and lead to significant errors. To quantify these errors, we integrate apatite fission track (AFT) ages from the central Himalaya with a 3-D coupled thermokinematic model, from which sample cooling ages are predicted using a cooling-rate-dependent algorithm. By changing the slip partitioning between faults near the Main Central thrust and the Main Frontal thrust system at the Himalayan range front, …