Geology Commons^™

Organochlorine Chemical Residues In Northern Cardinal (Cardinalis Cardinalis) Eggs From Greater Washington, Dc Usa, Christopher J. Schmitt, Kathy E. Echols, Paul H. Peterman, Carl E. Orazio, K. Christiana Grim, Shirlee Tan, Nora E. Diggs, Peter P. Marra

United States Geological Survey: Staff Publications

Northern Cardinal eggs from six neighborhoods near Washington DC were analyzed for organochlorine pesticides and PCBs. All compounds were detected more frequently and at higher concentrations in more heavily urbanized neighborhoods. DDT (mostly as p,pʹ-DDE) was detected in all neighborhoods. p,pʹ-DDT was typically 0.5‒16 ng/g (ww) in most suburban neighborhoods but was not detected (< 0.1 ng/g) in more rural areas; however, p,pʹ-DDT was 127‒1130 ng/g in eggs from two suburban Maryland nests and comprised 65.7% of total p,pʹ-DDT isomers in the most contaminated sample, indicating recent exposure to un-weathered DDT. Total chlordane (sum of 5 compounds) was 2‒70 ng/g; concentrations were greatest in older suburban neighborhoods. Total PCB (sum of detected congeners) was < 5‒21 ng/g. Congener patterns were similar in all neighborhoods and resembled those typical of weathered mixtures. Results indicate that wildlife remains exposed to low concentrations of legacy contaminants in suburban neighborhoods and that cardinal eggs can be used to monitor local- ized contamination.

Reconstruction Of Antarctic Cenozoic Paleoenvironments Through Palynological Analysis Of Subglacial Lake And Ice Stream Sediments, Patrick Baudoin

LSU Master's Theses

The West Antarctic Ice Sheet (WAIS), with a large portion being grounded below sea level, is historically known for its instability. Timing and evaluating the magnitude of WAIS advance and retreat is essential to improve our understanding of control mechanisms. The scarcity of accessible subglacial geology in areas such as the Siple Coast in West Antarctica limits our understanding and ability to gauge WAIS response to environmental changes. To evaluate the ice-sheet history around the Siple Coast, i.e., when it was last covered by vegetation, access to sediment immediately below the ice-sheet is essential. In the absence of large-scale drilling, …

Provenance And Paleogeography Of The 25-17 Ma Rainbow Gardens Formation: Evidence For Tectonic Activity At Ca. 19 Ma And Internal Drainage Rather Than Throughgoing Paleorivers On The Southwestern Colorado Plateau, Melissa A. Lamb, L. Sue Beard, Malia Dragos, Andrew D. Hanson, Thomas A. Hickson, Mark Sitton, Paul J. Umhoefer, Karl E. Karlstrom, Nelia Dunbar, William Mcintosh

Geoscience Faculty Research

The paleogeographic evolution of the Lake Mead region of southern Nevada and northwest Arizona is crucial to understanding the geologic history of the U.S. Southwest, including the evolution of the Colorado Plateau and formation of the Grand Canyon. The ca. 25–17 Ma Rainbow Gardens Formation in the Lake Mead region, the informally named, roughly coeval Jean Conglomerate, and the ca. 24–19 Ma Buck and Doe Conglomerate southeast of Lake Mead hold the only stratigraphic evidence for the Cenozoic pre-extensional geology and paleogeography of this area. Building on prior work, we present new sedimentologic and stratigraphic data, including sandstone provenance and …

Holocene Climate Evolution Of Continental Western Eurasia Constrained By Stable-Isotope And Cation Geochemistry Of U-Th-Dated Speleothems And Meteogenic Travertine, Jonathan Lloyd Baker

UNLV Theses, Dissertations, Professional Papers, and Capstones

Reliable reconstructions of global and regional climate during the Holocene (11,700 years ago to present) are vital to constraining the natural range of climate variability and testing state-of-the-art models, which seek to forecast the near- and long-term impact of anthropogenic greenhouse forcing. Much of continental Eurasia is still underrepresented, however, in geological proxy reconstructions of Holocene climate variability, and the vast majority of paleoclimate data only reflect conditions during peak summer months (JJA) or the growing season. The paucity of winter proxy data has therefore been cited as a possible explanation for the current mismatch between geological proxy-based and climate-model …

Structural Evolution And Regional Implications Of The Arrowhead Mine Fault Within The Pahranagat Shear Zone, Nevada, Usa, Michael Dennis Evans

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Basin and Range province is characterized by normal faults associated with

extension, but the occurrence of strike-slip faults and the seismic hazard accompanying

them is less understood. One major strike-slip zone, the Pahranagat shear zone (PSZ),

lies in Lincoln County, Nevada and within the boundary zone between northern Basin

and Range (NBR) and central Basin and Range (CBR) sub-provinces. The PSZ is a 20-

25 km long zone of Cenozoic left-lateral faults. The Arrowhead Mine Fault (AMF) is one

of the three major faults in the PSZ. The western AMF and the faults that surround and

abut it are …

A Novel Approach To Analyzing Strain Heterogeneity In Polycrystalline Quartz Specimens Deformed At High Pressure And Temperature, Nolan Ambrose Regis

UNLV Theses, Dissertations, Professional Papers, and Capstones

Rheological studies of rocks and minerals allow researchers to study the grain-scale deformation mechanisms that govern large-scale geologic processes from mountain building to mantle mixing. Deforming rock samples with high pressure and temperature apparatuses similar to the Griggs piston cylinder apparatus allows us to simulate deformation at depth. However, many apparatuses are limited to “cook-and-look” analysis and require modeling techniques to determine the evolution of deformation patterns found in experimental samples. A previous study used two-dimensional finite element models to analyze the development of stress and strain patterns in polycrystalline rocks. The study suggested rhythmic patterns in deformed rocks develop …

Miocene-Quaternary Deformation Along The Central Maynard Lake Fault, Pahranagat Shear Zone, Nevada, Alexander Peck

UNLV Theses, Dissertations, Professional Papers, and Capstones

The left-lateral Pahranagat shear zone (PSZ) and Caliente-Enterprise zone (CEZ) exist at the boundary between two sub-provinces, the Northern (NBR) and Central Basin and Range (CBR). The PSZ contains three major ENE striking sinistral faults, including the Maynard Lake fault (MLF), which is the longest fault and marks the southern boundary of the zone. The PSZ has been suggested to be a transfer zone, but little is known about the structures along these major faults that are involved in strain transfer. These left-lateral systems exist within the Central Nevada seismic belt which has experienced significant earthquakes in recent history. Possible …

Petrology And Geochemistry Of The Enriched Poikilitic Shergottite Northwest Africa 10169: Insight Into The Martian Interior, Logan Matthew Combs

UNLV Theses, Dissertations, Professional Papers, and Capstones

The martian meteorite Northwest Africa (NWA) 10169 is classified as a new member of the geochemically enriched poikilitic shergottites, based on mineral composition, Lu-Hf isotope systematics, and rare earth element (REE) composition. Akin to other poikilitic shergottites, it shows a similar bimodal texture to other enriched and intermediate poikilitic shergottites. In addition, olivine and pyroxene in the poikilitic zone have higher Mg#’s (Mg/Mg+Fe) than those in the interstitial areas, suggesting that the poikilitic texture represents early-stage crystallization, opposed to late-stage non-poikilitic crystallization. Calculated fO2 values are reduced (FMQ -2.3 ± 0.23) within the poikilitic texture, and more oxidized (FMQ -1.07 …

Investigating Trace Metal Sequestration Of Reducing Environments In Modern And Ancient Settings, Adam Charles Turner

LSU Doctoral Dissertations

The incorporation of trace metals into a variety of reducing sediments are important proxies for the oxic state of the water mass in which the sediments form. While much work has been done interpreting these proxies, questions remain on the exact processes and products in which trace metal proxies form. This work employs bulk geochemical techniques to investigate circulation in the Late Pennsylvanian North American Midcontinent Sea (NAMS), and then uses sequential extractions to further understand the chemical phases in which trace metals are incorporated. Sequential extractions are then used to further investigate how trace metals are sequestered in modern …

A Geophysical Delineation Of A Normal Fault Within The Gulf Coastal Plain, Montgomery County, Texas, Danielle Minteer

Electronic Theses and Dissertations

The Gulf Coast of Texas has been a known hydrocarbon basin for many years with various structural trapping mechanisms such as anticlines, faults and salt domes. While most large salt domes have been extensively studied in the Gulf Coastal Plain, many smaller normal faults have not been studied in detail. This research study employs an integrated geophysical approach to mapping the Big Barn fault in Montgomery County, Texas. This fault is located on the Gulf Coastal Plain and is approximately 20 miles north of Houston, Texas. Most normal faults in the Gulf Coastal Plain formed as a result of the …

Speleogenetic Evolution And Geological Remote Sensing Of The Gypsum Plain, Eddy County, New Mexico, Jessica Shields

Electronic Theses and Dissertations

Permian evaporites of the Gypsum Plain region of the Delaware Basin host extensive karst phenomena, as well as unique diagenetic alterations of host strata. Because of the complex, poorly understood hydrogeologic system, little has been established concerning the relation and evolution of the overprinted, modern and ancient karst manifestations within the Gypsum Plain, as a whole. Through a combination of traditional field studies and the development of improved remote sensing methodologies, this study established the speleogenetic evolution of the Gypsum Plain in relation to the greater tectonic, stratigraphic, hydrogeologic and climatic history of the Delaware Basin. Emphasis was focused on …

Birth And Evolution Of The Virgin River: ~1 Km Of Post-5 Ma Uplift Of The Western Colorado Plateau, Cory J. Walk

Earth and Planetary Sciences ETDs

The uplift history of the Colorado Plateau has been debated for over a century with still no unified hypotheses for the cause, timing, and rate of uplift. 40Ar/39Ar dating of semi-continuous basaltic volcanism over the past ~6 Ma within the Virgin River drainage system, southwest Utah and southern Nevada, provides a way to calibrate differential river incision and compare patterns of basaltic migration, mantle velocity structure, channel steepness, lithology, incision history and the birth and evolution of the Virgin River. New detrital sanidine ages constrain the arrival of the Virgin River across the Virgin Mountains to a maximum depositional age …

A Speleothem Record Of Climate Variability In Southwestern North America During Marine Isotope Stage 3, Justin G. Peinado

Earth and Planetary Sciences ETDs

During Marine Isotope Stage 3 (MIS-3) of the last glacial period, there were rapid transitions between warm and cold climates referred to as Dansgaard-Oeschgerr (DO) events. In Southwestern North America (SWNA), two speleothem paleoclimate records document changes in moisture source delivery in response to DO-events during MIS-3, but do not address potential changes in effective moisture for the region. In this study, we introduce a new high-resolution speleothem paleoclimate record from Carlsbad Cavern in the Guadalupe Mountains. The speleothem, sample BC-5, grew continuously from 46-31 kya during the latter half of MIS-3, based on U-Th dating. We also tied stable …

Transient Reactivation Of A Deep-Seated Landslide By Undrained Loading Captured With Repeat Airborne And Terrestrial Lidar, Adam M. Booth, Justin Mccarley, Jason Hinkle, Jean-Paul Ampuero, Michael P. Lamb

Geology Faculty Publications and Presentations

Landslides reactivate due to external environmental forcing or internal mass redistribution, but the process is rarely documented quantitatively. We capture the three-dimensional, 1-m resolution surface deformation field of a transiently reactivated landslide with image correlation of repeat airborne lidar. Undrained loading by two debris flows in the landslide’s head, rather than external forcing, triggered reactivation. After that loading, the lower 2 km of the landslide advanced by up to 14 m in 2 years before completely stopping. The displacement field over those 2 years implies that the slip surface gained 1 kPa of shear strength, which was likely accomplished by …

Preliminary Sedimentology And Stratigraphy Of The Enigmatic Middle Lake Beds Succession (Pleistocene?) In The Rukwa Rift Basin, Tanzania, Cassy Mtelela

Tanzania Journal of Science

This paper presents sedimentology and stratigraphic overview of a series of previously unrecognized lithostratigraphic unit in the Rukwa Rift Basin, Tanzania. Based on the cross-cutting relationship and pilot detrital zircon geochronology, these isolated, enigmatic strata are herein informally termed the middle Lake Beds (mLB). Facies analysis reveals that the mLB units were deposited within a complex array of depositional environments, ranging from alluvial to fluvial channels, floodplains and shallow lakes.  The mLB are characterised herein as isolated outcrop exposures with uncertain age relationships, but which can be divided into five distinctive lithostratigraphic units herein identified as informal members (A-E). These …

Indoor Radon Concentration Levels And Annual Effective Doses For Residence Of Houses Near Uranium Deposit In Bahi District, Dodoma, Tanzania, Najat K. Mohammed, Erasto Focus

Tanzania Journal of Science

The objective of this study was to determine the levels of indoor radon concentration in houses in Bahi District situated in the neighbourhood of uranium deposit. The study aimed also to assess the annual effective dose due to indoor radon exposure to individuals residing in the houses as a step to control the radon exposure in Tanzania. Two villages were involved in this study; Bahi Makulu, which is within the proximity of Uranium deposit and Bahi Sokoni, which is about 7 km from the deposit. The Indoor radon concentration levels were detected using Alpha Guard radon monitor and the obtained …

Assessment Of Indoor Radon-222 Concentrations In The Vicinity Of Manyoni Uranium Deposit, Singida, Germana W Mlay, Ismael N Makundi

Tanzania Journal of Science

This study aimed to assess indoor radon concentrations in the vicinity of the Manyoni Uranium Deposit in Singida. The concentrations were measured for two months in 32 houses in the vicinity of Manyoni Uranium Deposit and 9 houses at Manyoni town using a portable radon gas monitor (Alpha –GUARDTM). The radon concentrations ranged from 27±3 to 518±28 Bq/m3with the overall mean of 166±12 Bq/m3 which is above recommended values of 100 Bq/m3 and 148 Bq/m3 set by WHO (World Health Organization) and EPA (Environmental Protection Agency's), respectively. The overall mean of indoor radon concentrations from each village were Kipondoda (169±13 …

Petrographic And Stratigraphic Analysis Along The Lower Cretaceous Strata, In Kimble County Texas, Austin C. Wilkerson

Student Publications

The upper Trinity Group is predominantly a carbonate system with minor clastic couplets that were deposited during the Middle Cretaceous in the south Llano Uplift region. The upper Trinity Group was deposited on a southward dipping platform in the Kimble County area. Stratigraphic units of the upper Trinity Group are the Hensel Formation, determined to be supratidal claystones, the Glen Rose Formation, which are mudstones that were deposited in a carbonate lagoon, and the Walnut and Fort Terrett formations, which are wackestones to packstones interpreted to have been deposited on a shallow carbonate shelf.

Nine stratigraphic sections were measured along …

Cyanobacteria Reduce Quagga Mussel (Dreissena Rostriformis Bugensis) Spawning And Fertilization Success, Anna G. Boegehold, Nicholas S. Johnson, Jeffrey L. Ram, Donna R. Kashian

Environmental Science and Geology Faculty Research Publications

Quagga mussels (Dreissena rostriformis bugensis) are highly fecund broadcast spawners invasive to freshwaters of North America and western Europe. We hypothesized that environmental cues from phytoplankton can trigger gamete release in quagga mussels. Nutritious algae may stimulate dreissenid spawning, but less palatable food, such as bloom-forming cyanobacteria, could be a hindrance. The objective of our study was to test whether exposure to cyanobacteria can inhibit quagga mussel spawning and fertilization. We assessed spawning in the presence of serotonin, a known spawning inducer, where adult quagga mussels placed in individual vials were exposed to 13 cyanobacteria cultures and purified algal toxin …

Heat/Mortality Sensitivities In Los Angeles During Winter: A Unique Phenomenon In The United States, Adam J. Kalkstein, Laurence S. Kalkstein, Jennifer K. Vanos, David P. Eisenman, Paul Grady Dixon Ph.D.

Geosciences Faculty Publications

Background: Extreme heat is often associated with elevated levels of human mortality, particularly across the mid-latitudes. Los Angeles, CA exhibits a unique, highly variable winter climate, with brief periods of intense heat caused by downsloping winds commonly known as Santa Ana winds. The goal is to determine if Los Angeles County is susceptible to heat-related mortality during the winter season. This is the first study to specifically evaluate heat-related mortality during the winter for a U.S. city. Methods: Utilizing the Spatial Synoptic Classification system in Los Angeles County from 1979 through 2010, we first relate daily human mortality to synoptic …