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Full-Text Articles in Earth Sciences

Late Quaternary Glacier Fluctuations And Vegetation Change In The Northwestern Ahklun Mountains, Southwestern Alaska, Yarrow L. Axford May 2000

Late Quaternary Glacier Fluctuations And Vegetation Change In The Northwestern Ahklun Mountains, Southwestern Alaska, Yarrow L. Axford

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This research examines moraine and lacustrine records of glacier fluctuations, in combination with palynological records of vegetation change, from the previously unstudied northwestern Ahklun Mountains in southwestern Alaska.

Moraine mapping reveals that ice-cap outlet glaciers in the study area extended ca. 60 km from the center of the Ahklun Mountians ice dome during the early Wisconsin (sensu lato), and ca. 40 km during the late Wisconsin. Correlations with well-studied moraines in the southern Ahklun Mountains indicate an asymmetry of glaciation over the range, with ice-cap outlet glaciers more extensive to the south. This asymmetry was more striking during …


Evaluating Snowmelt Runoff, Infiltration, And Erosion In A Sagebrush-Steppe Ecosystem, Eric K. Duffin May 1999

Evaluating Snowmelt Runoff, Infiltration, And Erosion In A Sagebrush-Steppe Ecosystem, Eric K. Duffin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Production of low-level radioactive waste (LLRW) has created a need for safe storage facilities. These facilities must be capable of isolating radioactive waste and preventing contamination from physical or biological intrusion until the waste material is isotopically stable. At the present time, managers of the Idaho National Engineering and Environmental Laboratory (INEEL) have a substantial database characterizing rainfall events and the subsequent impact on integrity of shallow land burial sites used for storage of LLRW. Little information has been gathered describing the processes of snow accumulation/ablation and the resulting impact on storage facilities. This study examines snowmelt runoff, infiltration, and …


Chemical And Hydrostratigraphic Characterization Of Ground Water And Surface Water Interactions In Cache Valley, Utah, J. Mike Robinson May 1999

Chemical And Hydrostratigraphic Characterization Of Ground Water And Surface Water Interactions In Cache Valley, Utah, J. Mike Robinson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A series of five east-west and two north-south hydrostratigraphic cross sections were drawn from drillers' logs of water wells within the southern half of Cache Valley, Utah. These cross-sections demonstrate that ground water flow to streams is restricted by a continuous low- II permeability layer, nearly 100-feet thick. This layer was correlated to the lake-bottom deposits of the Bonneville (30,000 -13,000 years ago) and Little Valley (140,000 - 90,000 years ago) cycles of the ancient Lake Bonneville.

The most productive aquifers in the valley, collectively termed the principal aquifer , are in the southeast corner , approximately between Smithfield and …


Cenozoic Structural And Stratigraphic Evolution Of The Southeastern Salmon Basin, East-Central Idaho, James J. Blankenau May 1999

Cenozoic Structural And Stratigraphic Evolution Of The Southeastern Salmon Basin, East-Central Idaho, James J. Blankenau

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The southeastern Salmon basin (SB) of east-central Idaho is a complex east-dipping half graben containing four unconformity-bounded sequences of Tertiary volcanic, alluvial fan, lacustrine, and fluvial deposits. From oldest to youngest these are the Challis volcanic group, sedimentary rocks of Tendoy (new name), sedimentary rocks of Sacajaweja (new name), and Quaternary-Tertiary deposits . The thick sequence of volcanic rocks was deposited in a southeast-trending paleovalley . New mapping, cross-cutting relationships, 40Ar/39Ar age determinations, and angular unconformities show that the SB has experienced at least four episodes of extension, and that it lies in the core of an …


Sequence Stratigraphy And Paleoecology Of The Middle Cambrian Spence Shale Member Of The Langston Formation Of Northeastern Utah And Southeastern Idaho, Scott H. Wright May 1999

Sequence Stratigraphy And Paleoecology Of The Middle Cambrian Spence Shale Member Of The Langston Formation Of Northeastern Utah And Southeastern Idaho, Scott H. Wright

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Cambrian Spence Shale Member contains meter-scale, shallowing-up cycles (parasequences) and record approximately 360 ky of deposition. These meter-scale cycles are nested within transgressive systems tracts (TST) and highstand systems tracts (HST) which reflect different stages of a lower-order, higher-magnitude sea-level excursion.

Fossil assemblages are located in stratigraphic positions within the Spence Shale Member that can be predicted on the basis of sequence architecture. The cycle architecture, taphonomy, and geochemistry of the Spence parasequences confirm synthetic sections and theoretical models of meter-scale cycles developed in other studies. Delineation of meter-scale cycles, based on taphonomic and sedimentologic criteria, allows high-resolution …


Prediction Of Suburban Encroachment On The Ethan Allen Firing Range And Camp Johnson, Chittenden County, Vermont, John D. Calandrelli May 1999

Prediction Of Suburban Encroachment On The Ethan Allen Firing Range And Camp Johnson, Chittenden County, Vermont, John D. Calandrelli

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Suburban encroachment is a growing concern for many National Guard training installations. The Ethan Allen. Firing Range and Camp Johnson, Vermont, are either experiencing or are completely enclosed by urban encroachment. The objective of this study was to analyze the trends of suburban growth within Chittenden County, Vermont, to evaluate growth and explore future training site viability of the Ethan Allen Firing Range and Camp Johnson.

This study focused on historical data, recent real estate transactions, population projections, and county plans for growth. Using historical and contemporary data, I developed a predictive model of suburban encroachment on Camp Johnson and …


Molecular Characterization Of Soil Ammonia-Oxidizing Bacteria Based On The Genes Encoding Ammonia Monooxygenase, Jose Javier Alzerreca May 1999

Molecular Characterization Of Soil Ammonia-Oxidizing Bacteria Based On The Genes Encoding Ammonia Monooxygenase, Jose Javier Alzerreca

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ammonia-oxidizing bacteria (AOB) are chemolithotrophs that oxidize ammonia/ammonium to nitrite in a two-step process to obtain energy for survival. AOB are difficult to isolate from the environment and iso lated strains may not represent the diversity in soil. A genetic database and molecular tools were developed based on the ammonia monooxygenase (AMO) encoding genes that can be used to assess the diversity of AOB that exist in soil and aquatic environments without the isolation of pure cultures. The amo genes have excellent potential as molecular markers; since AMO is only found in the AOB and is essential for their metabolism, …


Tertiary Stratigraphy And Structural Geology, Wellsville Mountains To Junction Hills, North-Central Utah, Kathryn M. Goessel May 1999

Tertiary Stratigraphy And Structural Geology, Wellsville Mountains To Junction Hills, North-Central Utah, Kathryn M. Goessel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study integrates detailed mapping of Tertiary deposits along the divide between the lower Bear River basin and the Cache Valley basin with several other techniques to generate a depositional model, define extension-related structures, and compile a geologic history for this part of the northeastern Basin and Range province. The study area is situated along the topographic divide between Box Elder and Cache Counties, Utah, from the Wellsville Mountains north almost to Clarkston Mountain. These ranges are cored by folded and thrusted Paleozoic rocks. They are bound on the west by normal faults of the Wasatch fault zone and on …


Utilization Of Spatially Distributed Soil Resources By Several Species Common To The Great Basin, Sarah Duke May 1998

Utilization Of Spatially Distributed Soil Resources By Several Species Common To The Great Basin, Sarah Duke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Heterogeneous spatial and temporal distributions of soil resources important to plant growth have been documented in the sagebrush steppe ecosystem. There can exist as much variability in soil resources within the root zone of individual plants as exists across an entire field. The objective of this dissertation research was to evaluate how plants respond to, utilize and influence the spatial heterogeneity of soil resources. The three specific sets of questions addressed are outlined in the three main chapters of this dissertation.

My first study addressed how the number and concentration of phosphorus (P) patches in the root zone of an …


Small Strike-Slip Faults In Granitic Rock: Implications For Three-Dimensional Models, Siang Joo Lim May 1998

Small Strike-Slip Faults In Granitic Rock: Implications For Three-Dimensional Models, Siang Joo Lim

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The geometry and mineralization features of small left-lateral strike-slip faults and associated fractures in Lake Edison Granodiorite of the central Sierra Nevada, California, were examined in order to model the three-dimensional structure of strike-slip faults. These faults, which are reactivated joints, were also examined to determine fault sizes, starting joint size, and evidence for fluid flow.

The associated secondary fractures are usually found in the dilational quadrants of fault-tip regions. The longest fault-segment trace is 32.14 m; the longest joint trace is 22 m. The joint population length (l) is represented by a power-law distribution (l-n …


Late Pleistocene Glacial Chronology Of The Western Ahklun Mountains, Southwestern Alaska, Jason P. Briner May 1998

Late Pleistocene Glacial Chronology Of The Western Ahklun Mountains, Southwestern Alaska, Jason P. Briner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

New glacial mapping and 35 cosmogenic 36Cl surface exposure ages, the first ever reported from Alaska, constrain the extent and timing of late Pleistocene glacial fluctuations in the western Ahklun Mountains, southwestern Alaska. Morphometric and soil relative-age data characterize two main drift units deposited during the Arolik Lake and Klak Creek glaciations, named herein. During the Arolik Lake glaciation (early Wisconsin), outlet glaciers emanated from an ice cap over the central portion of the Ahklun Mountains and deposited moraines at or beyond the modern coast. These moraines have slope angles averaging about 11° and crests averaging about 35 m …


Quaternary Amino Acid Geochronology Of The Lahontan Basin, Nevada, And The Chewaucan Basin, Oregon, Jeffrey Bigelow May 1998

Quaternary Amino Acid Geochronology Of The Lahontan Basin, Nevada, And The Chewaucan Basin, Oregon, Jeffrey Bigelow

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Amino acid geochronology based on fossil molluscs provides a useful approach to determining the Quaternary history of Great Basin lakes. The Lahontan basin, Nevada, and the Chewaucan basin, Oregon, in the northwest corner of the Great Basin, both contained lakes during the Quaternary. The aim of this study is to improve the Quaternary geochronology in these two basins by measuring time-dependent changes in amino acids preserved in fossil molluscan shells. The abundance of D-alloisoleucine relative to Lisoleucine (All) characterizes the extent of racemization, which increases with age and Ul forms the basis of relative and correlated ages. An age-calibration curve …


Three-Dimensional Structure Of Small Strike-Slip Fault Zones In Granitic Rock: Implications For Fault-Growth Models, Kim R. Robeson May 1998

Three-Dimensional Structure Of Small Strike-Slip Fault Zones In Granitic Rock: Implications For Fault-Growth Models, Kim R. Robeson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three small strike-slip fault zones exposed in granitic rock in the central Sierra Nevada, California, provide field-based data to construct three-dimensional representations of each fault zone in order to compare with the geometries predicted by existing fault-growth models. All three fault zones are nearly vertical, strike -N60°E, and have left-lateral slip. The fault zones range from 60 to 140 m in length and 1 to 12 m wide. Each fault zone consists primarily of parallel to subparallel fracture and fault traces 2 to 56 m long and is separated 25 cm to 7 m by intact rock. One fault zone …


Quaternary Bear River Paleohydrogeography Reconstructed From The 87sr/86sr Composition Of Lacustrine Fossils, David P. Bouchard May 1997

Quaternary Bear River Paleohydrogeography Reconstructed From The 87sr/86sr Composition Of Lacustrine Fossils, David P. Bouchard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Diverted from its former course to the Pacific Ocean by basalt flows in Gem Valley, Idaho, the Bear River presently flows south into the Bonneville Basin. Constraining the timing of the river's diversion is pivotal to understanding the hydrologic budgets, and thus the climatological implications of the Bonneville Basin lakes. This study employs strontium (Sr) isotopes in mollusc fossils as a tracer of the Bear River water that entered Lake Thatcher, a small, closed-basin lake into which the redirected river flowed en route to the Bonneville Basin. The Sr ratios, combined with the temporal control afforded by amino acid geochronology …


Channel Narrowing Of The Green River Near Green River, Utah: History, Rates, And Processes Of Narrowing, Tyler M. Allread May 1997

Channel Narrowing Of The Green River Near Green River, Utah: History, Rates, And Processes Of Narrowing, Tyler M. Allread

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Previous scientific research has documented channel narrowing on the Green River near Green River, Utah, but the exact timing, rates, and causal mechanisms of that narrowing have been the source of disagreement in the scientific literature. This thesis demonstrates that the Green River has narrowed in two separate periods during the last 100 years. The narrowing is driven primarily by changes in the hydrologic regime and not by the invasion of saltcedar. The channel narrowed between 1930 and 1938, when a shift from wetter than normal conditions to a period of draught led to a reduction in river discharge. Channel …


Identification Of Belowground Woody Structures Using Molecular Biomarkers, Benny R. Bobowski May 1997

Identification Of Belowground Woody Structures Using Molecular Biomarkers, Benny R. Bobowski

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Within the last two decades substantial progress has been made in understanding seed bank dynamics and the contribution of the soil seed bank to a post-disturbance plant community. There has been relatively little progress, however, in understanding perennial bud bank dynamics and the contribution of the soil bud bank to secondary succession. This lack of information is due primarily to the inability to reliably identify roots, rhizomes, and lignotubers that lie dormant beneath the soil surface. This scientific investigation, therefore, addressed the issue of identification of belowground woody structures.

The first objective was to develop a methodology that utilizes molecular …


Modelling Vegetation Cover Types Using Multiseasonal Remotely Sensed Data To Compare Ecotones At Multiple Spatial And Spectral Resolutions, Kimberly Patraw May 1997

Modelling Vegetation Cover Types Using Multiseasonal Remotely Sensed Data To Compare Ecotones At Multiple Spatial And Spectral Resolutions, Kimberly Patraw

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Army National Guard Bureau has implemented a cooperative project with Utah State University to help with the use, display, and evaluation of environmental data for maintaining land condition. Camp Grayling, Michigan, is comprised of deciduous and evergreen forest types. Use of remote sensing for classification has been limited in this region due to the difficulty of species-level classification using single-date remote-sensing techniques. Also, remote sensing has traditionally focused on mapping homogenous zones rather than vegetation boundaries, while one of the concerns for land managers is the nature of vegetation edges (ecotones).

This study analyzed each season and band from …


Stratigraphy, Geochronology, And Tectonics Of The Salt Lake Formation (Tertiary) Of Southern Cache Valley, Utah, Kristine A. Smith May 1997

Stratigraphy, Geochronology, And Tectonics Of The Salt Lake Formation (Tertiary) Of Southern Cache Valley, Utah, Kristine A. Smith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study synthesizes the deposition and tectonic evolution of the Tertiary deposits in southern Cache Valley, a narrow, north-trending valley in the northeastern Basin-and- Range Province. The surrounding mountains consist of Proterozoic and Paleozoic sedimentary rocks. Southern Cache Valley is an east-tilted half-graben. The oldest Tertiary sediments are on the west side of the basin, and the overall dip is to the east.

The Late Miocene to Early Pliocene Salt Lake Formation (Tsl) accumulated above the thin (to absent) Early to Middle Eocene Wasatch Formation (Tw) and the newly identified Fowkes and Norwood Tuff equivalents (Tfn; late Middle Eocene to …


Geomorphology Of The Green River In Dinosaur National Monument, Paul E. Grams May 1997

Geomorphology Of The Green River In Dinosaur National Monument, Paul E. Grams

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Longitudinal profile, channel cross-section geometry, and depositional patterns of the Green River in its course through the eastern Uinta Mountains are each strongly influenced by river-level geology and tributary sediment delivery processes. We surveyed channel cross sections at 1-km intervals, mapped surficial geology, and measured size and characteristics of bed material in order to evaluate the geomorphic organization of the 70- km study reach. Canyon reaches that are of high gradient and narrow channel geometry are associated with the most resistant lithologies exposed at river level and the most frequent occurrences of tributary debris fans. Meandering reaches that are characterized …


Geochemical, Petrologic, And Structural Characterization At Multiple Scales Of Deformation Associated With The Punchbowl Fault, Southern California, Steven E. Schulz May 1997

Geochemical, Petrologic, And Structural Characterization At Multiple Scales Of Deformation Associated With The Punchbowl Fault, Southern California, Steven E. Schulz

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Three traverses across the exhumed trace of the Punchbowl fault zone in the Pelona Schist, southern California, were examined at the millimeter to kilometer scales to determine the morphology, deformation mechanisms, and geochemistry of the fault zone in schistose rocks. The Pelona Schist is predominantly a quartz-albite-muscovite-actinolite schist with associated minor metabasalts. The Punchbowl fault zone, which is exhumed 2-4 km, has 44 km of right lateral slip, and is composed of a fault core enveloped by a damaged zone.

The fault core is a region of extreme slip localization that records most fault displacement. Deformation in the fault core …


Cenozoic Tectonic And Paleogeographic Evolution Of The Horse Prairie Half-Graben, Southwest Montana, Colby J. Vandenburg May 1997

Cenozoic Tectonic And Paleogeographic Evolution Of The Horse Prairie Half-Graben, Southwest Montana, Colby J. Vandenburg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Horse Prairie basin (HPB) of southwestern Montana is a complex, east dipping half-graben that contains three angular unconformity-bounded sequences of Tertiary lacustrine, paludal, and fluvial sediments overlying middle Eocene volcanic rocks. The basin is near the eastern edge of the Cordilleran thrust belt, and represents the western half of a larger Paleogene rift basin. Geologic mapping within the Everson Creek and Bannock Pass 7.5 minute quadrangles indicates that five temporally and geometrically distinct episodes of extension characterize the late Mesozoic (?) to Cenozoic tectonic evolution of the upper HPB.

The first episode of extension occurred prior to emplacement of …


A Hydrogeochemical Study Of The Evolution Of The Headwaters Of The Bear River In The Uinta Mountains, Utah, Michael F. Leschin May 1997

A Hydrogeochemical Study Of The Evolution Of The Headwaters Of The Bear River In The Uinta Mountains, Utah, Michael F. Leschin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The headwaters of the Bear River in the Uinta Mountains of Utah provide a good setting in which to examine the influence of geological materials on stream chemistry. Ionic contributions to the stream-water from soils, vegetation, and the atmosphere generally are sparse enough that they do not mask the geologic contributions. Samples from 37 sites on the four major headwater streams and several minor tributaries were examined geochemically. Data derived from the samples allowed the construction of a hydrogeochemical weathering model specific to the study area. A significant feature of this model is that carbonic acid is the dominant chemical …


A Slow-Release Nitrogen Fertilizer: Ammonium-Loaded Clinoptilolite, T. Scott Perrin May 1997

A Slow-Release Nitrogen Fertilizer: Ammonium-Loaded Clinoptilolite, T. Scott Perrin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Crops grown in sandy soils require frequent irrigation. As a result, nitrogen (N) fertilizers. such as ammonium sulfate((NH4)2SO4), are leached from the rooting zone of crops. This loss of N increases N fertilizer use and the potential for nitrate (NO3-) contamination of water. Ammonium-loaded clinoptilolite (NH4+-Cp) may reduce this N leaching, increase N fertilizer use-efficiency, and prevent NO3- contamination of water while sustaining normal crop growth.

The potential of NH4+-Cp as a N fertilizer was assessed in three leaching experiments without plants and …


Pre-Late-Wisconsin Glacial History Of The Naknek River Valley, Southwestern Alaska, Caleb H. Thompson May 1996

Pre-Late-Wisconsin Glacial History Of The Naknek River Valley, Southwestern Alaska, Caleb H. Thompson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The lower Naknek River in southwestern Alaska dissects thick (~20m) exposures of Pleistocene glaciogenic sediments. The stratigraphy of the deposits and their physical, geochemical, mineralogical, and geochronological properties were studies to determine the number and timing of glacial advances represented. Multivariate data reduction methods (cluster and principal component analyses) were applied to the data to differentiate diamicton beds. The results show a clear separation of drift of the lower Naknek River valley from drift of northern Bristol Bay and from younger, moraine-comprising drift up valley. Within the Naknek River valley, however, there is no stratigraphic trend to the clusterings. The …


Paleoenvironmental And Stratigraphic Interpretation Of The Middle Cambrian Ute Formation, Northern Utah, Keith E. Eagan May 1996

Paleoenvironmental And Stratigraphic Interpretation Of The Middle Cambrian Ute Formation, Northern Utah, Keith E. Eagan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Middle Cambrian Ute Formation includes some 200 m of cyclically alternating carbonates and mud rocks. These are arranged in eight to nine, meter-scale, shallowing-upwards packages, representing deposition under predominantly subtidal conditions. The packages consist of vertical sequences of shale, silty limestone, oncolitic packstone, and oolitic grainstone that exhibit little variance in this general pattern. Small-scale unconformities separate the packages. The inferred depositional environment consists of an intrashelf basin that has a peritidal platform near its margins. The craton, which supplied most of the terrigenous sediment, was situated to the south (Cambrian orientation), and located near the equator. One cycle …


Structural Analysis Of The Mitten Park Reverse Fault And Related Deformation In Dinosaur National Monument, Northwestern Colorado And Northeastern Utah, Clint M. Brown May 1996

Structural Analysis Of The Mitten Park Reverse Fault And Related Deformation In Dinosaur National Monument, Northwestern Colorado And Northeastern Utah, Clint M. Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

An integrated field and structural analysis of the Mitten Park fault-fold structure, northwestern Colorado and northeastern Utah, examines its structural origin. The Mitten Park structure is a modified fault-propagation-fold. This new model incorporates faulting, folding, and fracturing in one deformational event to produce the Mitten Park fault and associated monocline.

The largest structure in the study area is the Mitten Park fault and associated monocline. The Mitten Park fault has approximately 127 meters (415 feet) of net slip, strikes S28°W and dips 55°WNW. In the footwall, net shortening was accommodated by reverse and normal faulting. Faulting was the result of …


Hydrochemical Definition Of Ground Water And Surface Water, With An Emphasis On The Origin Of The Ground-Water Salinity In Southern Juab Valley, Juab County, Utah, Heidi K. Hadley May 1996

Hydrochemical Definition Of Ground Water And Surface Water, With An Emphasis On The Origin Of The Ground-Water Salinity In Southern Juab Valley, Juab County, Utah, Heidi K. Hadley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As part of a U.S. Geological Survey study in Juab Valley in central Utah from 1991 to 1994, the chemistry of ground - and surface -water samples was determined. Total dissolved solids in the ground water of southern Juab Valley have historically been higher, in general, than ground water in other areas of Utah. Total dissolved solids for ground-water samples from this study ranged from 623 to 3,980 milligrams/liter. High-sulfate chemical data of previous studies suggested that the major source of ground-water salinity is the dissolution of gypsum (hydrous calcium sulfate ) from the Arapien Shale. Sulfur-34 to sulfur-32 isotopic …


Aminostratigraphy Of Thatcher Basin, Se Idaho: Reassessment Of Pleistocene Lakes, Amy Hochberg May 1996

Aminostratigraphy Of Thatcher Basin, Se Idaho: Reassessment Of Pleistocene Lakes, Amy Hochberg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Quaternary geologic history of Lake Thatcher, southeastern Idaho, is pivotal in determining when the Bear River carved its through-flowing channel into the Bonneville Basin. Bright's reconstruction of the history of Lake Thatcher was based on 14C dates that are now known to be inaccurate. Lava Creek B ash found interbedded with lacustrine sediment suggests that Thatcher Basin contained a lake well before Bright's original estimate of 34 ka.

D/L ratios, which measure the extent of racemization in fossil gastropods, in conjunction with paleosols and tephra, were used to correlate between four localities across Thatcher Basin to reassess lake-level …


The Effect Of Salinity Level Upon The Yield, Root Growth, And Water Extraction Of Contrasting Rooting Subpopulations Of Alfalfa (Medicago Sativa) Under Conditions Of Zero Leaching, Laura A. Vincent May 1996

The Effect Of Salinity Level Upon The Yield, Root Growth, And Water Extraction Of Contrasting Rooting Subpopulations Of Alfalfa (Medicago Sativa) Under Conditions Of Zero Leaching, Laura A. Vincent

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A major problem in irrigated agriculture in the Western U.S. is the gradual accumulation of salinity in the plant root zone. These nonuniformly saline soils contain increasing amounts of salinity with depth, and salt accumulation is accelerated in situations where leaching is minimized. Root growth and thus plant yield is limited in these soils due to decreased water uptake. We studied the root growth of two subpopulations of alfalfa differing in their ability to produce fibrous roots to determine if altering root morphology would increase plant yield and water extraction, in an irrigated saline soil.

Soil profiles for a control …


Evaluation Of Lake Fertilization As A Tool To Assist In The Recovery Of The Snake River Sockeye Salmon (Oncorhynchus Nerka), Howard P. Gross May 1995

Evaluation Of Lake Fertilization As A Tool To Assist In The Recovery Of The Snake River Sockeye Salmon (Oncorhynchus Nerka), Howard P. Gross

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

I analyzed lake fertilization (with nitrogen and phosphorus) as a tool to assist in the recovery of the Snake River sockeye salmon (Oncorhynchus nerka) in the oligotrophic Sawtooth Valley Lakes in southcentral Idaho. These analyses involved monitoring, manipulating, and modelling several aspects of the lakes' primary producer, nutrient, and light parameters.

In Pettit Lake, I evaluated the effects of metalimnetic and epilimnetic fertilization in 330-m3 mesocosms. The metalimnetic treatment was equal to or more effective than the epilimnetic treatment in increasing chlorophyll a, phytoplankton biovolume, and primary productivity, yet caused smaller changes in periphyton growth and …