Earth Sciences Commons^™

The 2003 Boumerdes, Algeria Earthquake: Regional Moment Tensor Analysis, Jochen Braunmiller, Fabrizio Bernardi

School of Geosciences Faculty and Staff Publications

We used regional broadband seismograms to determine seismic moment tensors for the destructive May 21, 2003 Boumerdes (Algeria) M_w = 7.0 earthquake and its larger aftershocks. Fully automatic inversions using near-real time data provided solutions for seven M_w ≥ 4.7 events within 90 minutes after event occurrence. After adding off-line data, we manually obtained 30 solutions (M_w ≥ 3.8) from May 2003 to January 2004. All have shallow source depths (6–21 km). The median P-axis orientation (338°) of 24 thrust and four strike-slip events is consistent with Africa-Eurasia plate motion (330°). The main shock hypocenter at 8–10 …

Evolution Of A Late Cenozoic Supradetachment Basin Above A Flat-On-Flat Detachment With A Folded Lateral Ramp, Se Idaho, A. N. Steely, Susanne U. Janecke, S. P. Long, S. C. Carney, R. Q. Oaks Jr., V. E. Langenheim, P. K. Link

Geosciences Faculty Publications

Uplift and exposure of the Bannock detachment system and the synextensional basin fill deposits of the Salt Lake Formation provide a unique exposure of the three-dimensional geometries of a low-angle normal fault system and the stratal architecture of the overlying supradetachment basin. Within this system, structural and stratigraphic analyses, outcrop patterns, tephra geochronology, and geological cross sections document several important relationships: (1) the Bannock detachment system developed above the Sevierage Cache-Pocatello culmination and resembles the Sevier Desert detachment in its geometry, structural setting, and kinematic evolution; (2) the Bannock detachment system initiated and slipped at low angles; (3) flat-on-flat, ramp-flat, …

Geologic Map Of The Bachelor Mountain 7.5' Quadrangle Beaverhead County, Montana, Susanne U. Janecke, R. J. Dorsey, J. C. Kickham, J. P. Matoush, W. Mcintosh

Geosciences Faculty Publications

Geologic Map of the Bachelor Mountain 7.5’ Quadrangle Beaverhead County, Montana Geologic Summary The Bachelor Mountain quadrangle is located in the Horse Prairie Creek drainage basin of southwest Montana and contains exposures of Middle Proterozoic metasedimentary rocks and eighteen map units of Eocene to Oligocene basin-fill deposits assigned to the Medicine Lodge beds. Locally, overlying upper Oligocene to lower Miocene(?) Everson Creek beds and late early to early late Miocene Bannack Pass beds are also preserved as basin-fill deposits. The Medicine Lodge beds were deposited in an early basin, the Grant protobasin (Fig. 1a), during slip on the Muddy-Grasshopper detachment …

Agraphorura Calvoi N. Sp. From Venezuelan Caves (Collembola: Onychiuridae), Javier I. Arbea

International Journal of Speleology

A new species of Agraphorura (Collembola: Poduromorpha: Onychiuridae) from caves in the Nort-West of Venezuela is described. A. calvoi n. sp. can be distinguished from its congeners by the following combination of characters: antennal organ III with four papillae, 32/133/33343 dorsal pseudocellar formula, 3/000/0112 ventral pseudocellar, subcoxae each with two pseudocelli, postantennal organ with 7-9 vesicles, unguiculus with a basal lamella, tibiotarsi I-III with 19,19,18 setae (distal whorl of 9 setae). A table with the differential characters, as well as an identifi cation key for all of the known species of Agraphorura are provided.

Burial Of Terrestrial Organic Matter In Marine Sediments: A Re-Assessment, David J. Burdige

OES Faculty Publications

Calculations based on recent observations indicate that approximately one third of the organic matter presently being buried in marine sediments may be of terrestrial origin, with the majority of this terrestrial organic matter (TOM) burial occurring in muddy, deltaic sediments. These calculations further suggest that the remineralization of terrestrial organic matter in the oceans is also much less efficient than that of marine organic matter. These two underappreciated observations have important implications in terms of our understanding of the controls on the global carbon cycle. From a paleoceanographic perspective, the results presented here also suggest that changes in TOM burial …

Iron In The Sargasso Sea (Bermuda Atlantic Time-Series Study Region) During Summer: Eolian Imprint, Spatiotemporal Variability, And Ecological Implications, Peter N. Sedwick, T. M. Church, A. R. Bowie, C. M. Marsay, S. J. Ussher, K. M. Achilles, P. J. Lethaby, R. J. Johnson, M. M. Sarin, D. J. Mcgillicuddy

OES Faculty Publications

We report iron measurements for water column and aerosol samples collected in the Sargasso Sea during July-August 2003 (summer 2003) and April-May 2004 (spring 2004). Our data reveal a large seasonal change in the dissolved iron (dFe) concentration of surface waters in the Bermuda Atlantic Time-series Study region, from ∼1-2nM in summer 2003, when aerosol iron concentrations were high (mean 10 nmol/m^-3), to ∼0.1-0.2nM in spring 2004, when aerosol iron concentrations were low (mean 0.64 nmol/m^-3). During summer 2003, we observed an increase of ∼0.6nM in surface water dFe concentrations over 13 days, presumably due to …

A Unique Seasonal Pattern In Phytoplankton Biomass In Low-Latitude Waters In The South China Sea, Chun-Mao Tseng, George T. F. Wong, I.-I. Lin, C.-R. Wu, K.-K. Liu

OES Faculty Publications

A distinctive seasonal pattern in phytoplankton biomass was observed at the South East Asian Time series Study (SEATS) station (18°N, 116°E) in the northern South China Sea (SCS). Surface chlorophyll-a, depth integrated chlorophyll-a and primary production were elevated to 0.3 mg/m³, ~35 mg/m² and 300 mg-C/m²/d, respectively, in the winter but stayed low, at 0.1 mg/m³, ~15 mg/m² and 110 mg-C/m²/d as commonly found in other low latitude waters, in the rest of the year. Concomitantly, soluble reactive phosphate and nitrate+nitrite in the mixed layer also became …

Variability Of Sea Ice Cover In The Chukchi Sea (Western Arctic Ocean) During The Holocene, Anne De Vernal, Claude Hillaire-Marcel, Dennis A. Darby

OES Faculty Publications

Dinocysts from cores collected in the Chukchi Sea from the shelf edge to the lower slope were used to reconstruct changes in sea surface conditions and sea ice cover using modern analogue techniques. Holocene sequences have been recovered in a down-slope core (B15: 2135 m, 75°44'N, sedimentation rate of ~1cm kyr-¹) and in a shelf core (P1: 201 m, 73°41'N, sedimentation rate of ~22 cm kyr^-1). The shelf record spanning about 8000 years suggests high-frequency centennial oscillations of sea surface conditions and a significant reduction of the sea ice at circa 6000 and 2500 calendar (cal) …

Hydrographic And Biological Changes In The Taiwan Strait During The 1997-1998 El Niño Winter, S. Shang, C. Zhang, H. Hong, Q. Liu, G. T. F. Wong, C. Hu, B. Huang

OES Faculty Publications

During the 1997–1998 El Niño event, the average sea surface temperature (SST) in the Taiwan Strait (TWS) in the winter was ~1.4°C higher than that of the winter climatological mean. The areal ratio of the warm water (≥2°C above the regional mean) to the cold water (≥2°C below the regional mean) in the TWS increased by 25% while the area of the eutrophic water (chlorophyll a >1 mg m^-3) was halved. Field observations also indicate that the mixed layer in the TWS became more nutrient-poor during this winter. These observations are consistent with a diminished advection of the …

Oceanographic Conditions And Diversity Of Sea Stars (Echinodermata: Asteroidea) In The Gulf Of California, México, Carlos E. Cintra-Buenrostro, Hector Reyes-Bonilla, Maria Dinorah Herrero-Perezrul

School of Earth, Environmental, & Marine Sciences Faculty Publications

Species richness is one of the best indicators of biodiversity. However, there are few investigations on concordance of diversity patterns and environmental settings for marine regions. The objectives of this study were to correlate species richness of shallow water (< 200 m deep) sea stars with key oceanographic factors in the Gulf of California, México, and to predict species richness of Asteroidea using multiple regressions. In these analyses the Gulf was divided into nine sections of one degree in latitude (from 23 - 31° N), at each section we recorded: continental shelf area (at 100 and 200 m depth), temperature mean and range at three depth levels (0, 60 and 120 m), thermocline depth, surface nutrient concentrations (nitrates, phosphates and silicates), surface photosynthetic pigment concentration, and integrated productivity. Sea star species richness at each latitudinal section was estimated from literature data, new collections and museum records. Species were assigned to one of the following feeding guilds: predators of small mobile invertebrates (I), detritivores (D), predators of colonial organisms (C), generalist carnivores (G), and planktivores (P). There are 47 shallow water asteroid species in the Gulf of California (16 I, 15 D, eight C, six G, one P and one not assigned). Total species richness and guild species richness showed strong latitudinal attenuation patterns and were higher in the southernmost Gulf, an area characterized by a narrow shelf, high temperature, and low nutrient concentrations. Species diversity for each guild was correlated to a set of oceanographic parameters: temperature, nitrate concentration, and integrated productivity were linked to richness in must cases. We detected that nutrients and surface pigments always presented negative relationships with species richness, indicating that productive environments limit asteroid diversity in the study area. Finally, the postulated regression models to estimate species richness from oceanographic data were significant and highly precise. We conclude that species richness of Asteroidea in the Gulf of California is related to oceanographic conditions and can be estimated from regional oceanographic information.

Agricultural Pollution Of Ground Water Near Gilbertville, Iowa, Paula Frost Even

Dissertations and Theses @ UNI

The transport of nutrients and contaminants from farm fields to the aquifer surrounding Gilbertville, Iowa, was monitored over a six-month period. The Gilbertville city water supply is obtained from the Silurian-Devonian aquifer, which has been determined to be highly susceptible to contamination because of the hydraulic characteristics of the aquifer and the overlying materials that allow contaminants to move to the aquifer fairly quickly. Monthly water samples were collected from April through September of 2004 from 26 private wells and 8 surface water sites within the source water protection area of the town's three wells. Each sample was tested for …

Carbonate Records Of Submarine Hydrocarbon Venting: Northern Gulf Of Mexico, Matthew S. Hackworth

LSU Doctoral Dissertations

Hydrocarbon seep sediments are examined from 3 sites in the Gulf of Mexico (Green Canyon Lease Blocks 232, 185, and 272) to relate the effects of gas hydrates and hydrocarbons on microbial process, pore fluid chemistry, and the processes of authigenic carbonate formation. Hydrocarbon-fueled microbial reactions result in pore fluids with lowered SO₄^2- (all consumed by –10 cm) and enrichments in H₂S, alkalinity, and DIC (up to 20 mmol, 30 meq/L, and 18 mmol/L, respectively) which promote carbonate formation. Pore fluid d¹³C_DIC (PDB) is influenced by thermogenic hydrocarbons and crude oil in GC …

The Stable Isotope Stratigraphy And Paleosols Of North America's Most Southern Exposure Of Late Paleocene/Early Eocene Fossiliferous Continental Deposits: Documenting The Initial Eocene Thermal Maximum In Big Bend National Park, Texas, Paul David White

LSU Doctoral Dissertations

A chemostratigraphic section across the Paleocene/Eocene boundary, using the stable isotopes of carbon and oxygen, has been developed for North America's most southern exposure of early Paleogene continental deposits in which the boundary is constrained by fossil mammals. A negative carbon excursion has been identified within C24r. The range in d¹³C values is from -8.1 to -13.2‰. Until the development of the chemostratigraphic section it was uncertain if the earliest Eocene was recorded in Big Bend. An early Wasatchian (Wa1) fossil site occurs stratigraphically higher than the carbon excursion and has yielded the stratigraphically lowest Hyracotherium in the …

Radon In Caves, Arrigo A. Cigna

International Journal of Speleology

The physical characteristics of radon are reported as well as its sources,the transport in rock and its behaviour in caves. Then, the instruments,both active and passive, used for the measurement of radon concentration are discussed by taking into account their respective advantages and disadvantages for the use in the cave environment. Since in many countries radon is the object of regulations that were adopted for radiation protection purposes, this aspect is examined and the recommendations issued by international organisations and enforced in different countries are reported. Materials, methods and other remarks on the limits implementation are also listed with the …

Cross-Formational Flow, Diffluence And Transfluence Observed In St. Beatus Cave And Sieben Hengste (Switzerland), Philipp Häuselmann

International Journal of Speleology

Observations in St. Beatus Cave and neighbouring caves revealed complex water flowpaths that can be used for explaining the behaviour of tracing experiments. The observations prove that even in vadose conditions, cross-formational flow, diffluences and transfluences are a quite common feature. Therefore, also the vadose karst has a very complex organisation.

Morphological And Physiological Abnormalities In Tissue Culture-Derived Date Palm (Phoenix Dactylifera L.) Plants, Hamad Saif Al-Mazroui

Theses

The UAE attaches great importance to agricultural development with a sound focus on date palms. This special attention is obvious in the ongoing expansion of agricultural resources and investments, the growing number of palm trees, and in the extensive use of modern technologies. Mass cultivation of date palm trees is required to continue according to the country's agricultural plans.

In order to achieve these agricultural expansion of date palm, new techniques of propagation other than traditional techniques (seed and offshoot propagation) are critically required. Tissue culture is a modern and reliable technology being one of the main methods for date …

Predicting The Spatial Distribution Of Organic Rich Sediments On The Swan Coastal Plain, Western Australia, David Blake

Theses : Honours

The Organic Rich Sediments (ORS) of the Swan Coastal Plain (SCP) are an important component of the ecosystem, an important source of habitat and refuge for many species of fauna and act as natural fire control mechanisms through edaphic measures within the landscape. There have been numerous impacts on ORS, with fire now rated as one of the imminent threats to the continued existence and functioning of these entities. Conversely fire is an important tool for land mangers in their efforts to promote biodiversity and manage fuel loads to prevent wildfires, at present many of these ORS are becoming victim …

Assessing Recharge And Discharge Across The Prairie Pothole Landscape: Application Of Spatial Hydrological Data And Statistical Analysis In A Groundwater Flow Model, Christopher D. Laveau

Theses and Dissertations

Quantifying the spatial and temporal dynamics between groundwater recharge, discharge, and wetlands is a necessary step to develop effective water management strategies. Wetlands in the northern Great Plains play a role in flood control, water supply, and regional ecology. The water budget of a wetland in the northern prairies is often an unequal balance between moisture input and output in which the permanence of a wetland depends on its groundwater budget. Identifying and quantifying groundwater recharge and discharge zones has applications in predicting the spatial and temporal distribution of wetlands.

The current work involved the application of a groundwater model …

Geomechanics Applied To Reservoir Development In The Coso Geothermal Field, Andrew J. Nygren

Theses and Dissertations

The Coso geothermal field is located approximately 220 kilometers north of Los Angeles, CA. In 2002, a project began to develop the east flank of the Coso geothermal field into an enhanced geothermal system (EGS); in such a system water is injected via injection well(s) into hot dry basement rock through naturally occurring or stimulated fractures. The injected water gathers heat from the reservoir rock before being extracted for direct use or energy production. To develop such a reservoir, adequate understanding of the reservoir geomechanics is necessary. This thesis investigates the state of stress and rock fractures, the existing permeable …

Isotopic Tracers As Evidence Of Denitrification In The Karlsruhe Aquifer, Eben J. Spencer

Theses and Dissertations

The Karlsruhe Aquifer of north-central North Dakota has experienced considerable nitrate contamination sparking an investigation by the North Dakota State Water Commission. Certain portions of the aquifer have experienced nitrate-N concentrations of up to seven times the drinking water standard. Although contamination is evident it is possible the NO₃¯ is naturally being eliminated by denitrification, whereby bacteria reduce NO₃¯ to nitrogen gas. Evidence of denitrification may be illustrated by accelerated reduction of NO₃¯ relative to the conservative tracer Cl¯ coupled with an increase in the heavy isotopes of 15N and 18O within the NO₃¯ ion. Such an increase is not …

Regional Stratigraphy Of The Newcastle Formation (Lower Cretaceous) In Eastern Montana And Western North Dakota, Adam J. Ulishney

Theses and Dissertations

The Newcastle Formation (Lower Cretaceous) consists of sandstone with interbedded shale, siltstone, and mudstone facies. This work shows that the regional stratigraphy of the unit is detailed enough for the interpretation of its depositional history and environments in eastern Montana. This work also illustrates the possible lowstand position of the Western Interior Seaway along with probable source areas providing sediments into the study area.

A total of 3446 geophysical wireline logs were used to determine formation tops of the Greenhorn, Mowry, Newcastle, Skull Creek, and Inyan Kara Formations. The log character of the Newcastle Formation was also described for all …

Hydrology Of The Springs, Seeps, And Fens At The Nature Conservancy's Pigeon Point Preserve, Ransom County, North Dakota, Corey W. Askin

Theses and Dissertations

Pigeon Point lies along the Sheyenne River in the west-central part of the Sheyenne Delta Aquifer, southeastern North Dakota. Groundwater discharges along a north-facing bluff at Pigeon Point and forms springs, seeps, and fens 'hosting atypical boreal species. The Nature Conservancy owns 231 ha at Pigeon Point, a tract that also includes the largest and least disturbed spring-fed stream in the region as well as some of the finest riparian forest in the state. In response to possible future groundwater diversion, the objectives of this study are: 1) to characterize the Sheyenne Delta Aquifer up-gradient from Pigeon Point, 2) to …

Reevaluation Of Species Concepts Of Uppermost Cretaceous Unionidae (Mollusca: Bivalvia) : Hell Creek Formation, Montana, U.S.A., Marron J. Bingle

Theses and Dissertations

Species are the basic units of life relative to taxonomy, and a practical definition of species is imperative to paleontology in order to promote reproducible, unambiguous criteria for accurately interpreting past species relationships. The need for a well-defined rubric for identifying species is evident in the freshwater mussel assemblage (Family Unionidae) in the Hell Creek Formation. The Hell Creek Formation unionid species were first described by Whitfield in 1903 and 1907. His descriptions were often based on differences of a single trait. In 1976, Russell reevaluated the original species descriptions, I but still based the classification of species on only …

Gis-Based Site Suitability Analysis For Planning Confined Animal Feeding Operations In Iowa, Brian Lance Bakker

Dissertations and Theses @ UNI

Confined Animal Feeding Operations (CAFOs) are becoming increasingly common on the Iowa landscape. These structures produce a very large number of livestock in a small area. The production of livestock is essential to the economy of Iowa, creating billions of dollars in revenue. However, when production is confined to small areas, large amounts of byproducts are produced that can cause a threat to the environment surrounding the areas of production. Thus, there is a need for careful planning, particularly the selection of suitable locations for future CAFO development. Currently, locations for CAFOs are simply chosen according to a producer's preference …

A Salt On The Land: The Osmolyte Production And Physiological Responses Of Selected Myrtaceae Species Exposed To Salt And Water Stress, Janelle Atkinson

Theses: Doctorates and Masters

Glasshouse trials were conducted on Calothamnus quadrifidus, Eucalyptus camaldulensis and Melaleuca uncinata

to test relative tolerance and uniformity of response in the Myrtaceae family to salt, waterlogging and salt x waterlogging. Seed sources from both saline (SA) and non-saline areas were used to compare differences in survival, growth and proline production to these stresses.

Conceptualisation Of Speleogenesis In Multi-Storey Artesian Systems: A Model Of Transverse Speleogenesis, Alexander Klimchouk

International Journal of Speleology

Conceptual and respective quantitative models of speleogenesis/karstification developed for unconfined aquifers do not adequately represent speleogenesis in confined settings. A conceptual model for speleogenesis in confined settings is suggested, based on views about hydraulic continuity in artesian basins and close cross-formation communication between aquifers in multi-storey artesian systems. Soluble units sandwiched between insoluble porous/fissured formations (common aquifers) initially serve as low permeability beds separating aquifers in a confined system. Conduits evolve as result of vertical hydraulic communication between aquifers across the soluble bed ("transverse speleogenesis"). Recharge from the adjacent aquifer is dispersed and uniform, and flow paths across the soluble …

Marine Ice Modification Of Fringing Ice Shelf Flow, Christina L. Hulbe, R. Johnston, Ian R. Joughin, Ted A. Scambos

Geology Faculty Publications and Presentations

Locally derived ice is often observed to fill through-cutting rifts and uneven fronts in ice shelves. That ice may nucleate as fast ice at the shelf front, by growth at the sea surface within rifts, or by basal accretion. Here, we investigate the role of such ice in the flow of the Brunt Ice Shelf and adjacent Stancomb-Wills ice tongue, along the Caird Coast of Antarctica. Much of the shelf system is severely rifted, with locally derived ice filling the space between rift walls and around ice rafts. A series of numerical experiments that account for thermal properties of the …