Physical Sciences and Mathematics Commons^™

Storm-Dominated Diatomite: Transport And Deposition From Micro-Texture, Taylor Kelln

Loma Linda University Electronic Theses, Dissertations & Projects

Unusually thick accumulations of diatomite and diatomaceous mud- and siltstones occur throughout the Mio-Pliocene along the Pacific margin. These extensive micro-fossil assemblages represent an important biostratigraphic resource, record of environmental conditions, and are economically relevant as unconventional reservoirs, sources and seals. Most depositional models for diatomaceous sediments tend to emphasize diatom productivity sufficient to overcome siliciclastic dilution and reflect a low-energy depositional regime with passive settling of diatoms through the water column. However, the diatomaceous sediments of the Pisco Basin, Peru, have been observed in longitudinally bedded, wavy, non-parallel laminated deposits, interpreted as hummocky-swaley cross-stratification. Other outcrop observations include tempestite-like …

Geomorphology Of The Potholes Of Rock Window Mesa, Chinle Valley, Az, Monte Fleming

Loma Linda University Electronic Theses, Dissertations & Projects

Potholes are depressions that have been carved out of bedrock. For this research project, we studied the 50 potholes on the top of Rock Window Mesa in Chinle Valley, AZ. Our first goal was to understand the processes currently affecting the addition or removal of pothole sediments. Our second goal was to understand pothole formation. While studying pothole sediment removal, we discovered that the wind speed threshold for deflation in the potholes is about 50 km/h, independent of pothole size. We conclude that deflation is the reason potholes don’t fill with sediment. In our study of pothole formation, we analyzed …

Conduction Plus Convection Heat Flow Modeling For The Linga Complex, Peruvian Coastal Batholith, Luciano Uriel González Olivares

Loma Linda University Electronic Theses, Dissertations & Projects

Factors affecting the thermal evolution of the Linga magmatic intrusion in the Ica-Pisco area of the Peruvian Coastal Batholith were studied using field work, petrography, geochemistry data, and computer modeling. Field work and petrography involved collecting samples for geochemical analysis and documenting widespread propylitic and potassic hydrothermal alteration. Major element geochemistry was used to estimate rock density, viscosity, liquidus temperature, and water content. The δ18O values of seven fresh samples showed a slightly increasing west-east and old-young trend of approximately 7-8‰, indicating an increasing crustal component. The δ18O and δD values for eleven altered samples indicated that alteration came mostly …

Unique Preservation Of Fossil Ghost Fish In The Green River Formation, Amanda L. Meacham

Loma Linda University Electronic Theses, Dissertations & Projects

Two beds with unique fossil fish preservation occur within the predominantly evaporite-rich, fossil poor Angelo Member in the Green River Formation in Fossil Basin, Wyoming. These two beds, termed “Ghost Fish” beds, contain fossil fish that are two-dimensional carbonaceous compressions with no bone and detailed soft part preservation. These beds were measured and samples were collected from 8 quarries and 19 additional locations. Stratigraphic sections and fossil content were recorded at each quarry location. Analysis included XRD, stable isotope, XRF, TOC, and SEM analysis. Results were inputted into tables, graphs, and spatial maps to show trends, interpret the paleoenvironment, and …

Cyclically-Forced Hyperpycnites Of The Ancient Colorado River Proximal Prodelta, Sandra R. Waresak

Loma Linda University Electronic Theses, Dissertations & Projects

Prodeltaic deposits record a distal, minimally reworked archive of dominant processes active at the fluvial-marine interface. The Fish Creek-Vallecito Basin (CA, US) preserves an ~3 km-thick, lower Pliocene, progradational deltaic succession formed when the ancestral Colorado River infiltrated the early Gulf of California. The interpreted prodeltaic unit in this succession (Mud Hills Member of the Deguynos Formation) contains an ~40 m-thick interval of rhythmic bedding with consistently alternating silt- to fine sand-dominated and clay-dominated beds forming couplets with an average thickness of 12 cm. Sedimentological analysis of the rhythmites reveals the couplets are laterally persistent with gradational to sharp, flat …

Compositional Diversity In Arcs: A Record Of Magmatic Processes In The Peru Coastal Batholith, Ica, Ana Maria Martinez Ardila

Loma Linda University Electronic Theses, Dissertations & Projects

Peruvian granitic plutons display evidence for crustal recycling and magma mixing. Evidence of physical and chemical processes operating during the formation of the Ica-Pisco complexes involves magma mixing and mingling as result of felsic and mafic interactions. Evidence of crustal recycling was identified from kilometer-scale cauldron subsidence, meter and centimeter-scale -stoping, and disaggregation. At the petrographic microscope scale, evidence for recycling and mixing between mantle and crustal magma during crystallization is found from disequilibrium features such as reaction rims, resorbed cores, and patchy zoning. Elemental and isotope geochemistry data indicate that mantle magmas have incorporated continental crust material from varying …

Interpreting Southern California Arc Geochemistry By Multivariate And Spatial Methods, Lance R. Pompe

Loma Linda University Electronic Theses, Dissertations & Projects

Exploratory data analysis methods of multivariate statistical techniques and spatial visualization are emerging trends in understanding big datasets. In this project, these techniques are applied to a large igneous geochemical dataset from the southern California segment of the Mesozoic Cordilleran arc to better understand magmatic and plate tectonic processes at a subduction zone. A set of 287 granitic samples collected by Baird and Miesch (1984) from the Peninsular Ranges batholith is analyzed for 38 geochemical elements. Patterns in both the geochemical variation and the spatial variation of this dataset are explored. Since geochemical data are compositional in nature, special treatment …

Depositional Model Of A Late Cretaceous Dinosaur Fossil Concentration, Lance Formation, Summer Rose Weeks

Loma Linda University Electronic Theses, Dissertations & Projects

A large Maastrichtian, nearly monospecific bonebed in the Lance Formation in eastern Wyoming has yielded 13,000 bones and fragments since 1996. Though excavation of the site continues, little is known of the circumstances and processes of deposition. This study aims to provide a depositional model for the bonebed. To accomplish this task we utilized 1D facies analysis of surrounding units and 3D analysis of the bonebed. The nature of the outcrop limited facies analysis to 1D. Four measured stratigraphic sections, each containing the bonebed unit, were taken and used in facies analysis. In addition, laterally continuous units were observed and …

The Growth And Ecology Of Upper Cambrian Microbialite Biostromes From The Notch Peak Formation In Utah, Ken P. Coulson

Loma Linda University Electronic Theses, Dissertations & Projects

Exposure of carbonate rocks within the uplifted mountains of southwestern Utah presents a unique opportunity to study the growth, morphology and ecology of two upper Cambrian microbialite reefs located within the Hellnmaria Member of the Notch Peak Formation. The first reef contains meter-length, strongly elongate microbialites that grew in a deep, subtidal marine environment. These elongate microbialites formed as a result of coalescence of round ‘algal’ heads, a process known to produce compound microbialite structures in shallow water, but seldom explored as a key factor in the elongation of deep, subtidal forms that grew in ancient environments. The second reef …

Sedimentology Of Kingston Peak Formation Kp1 Beds In Beck Canyon Region, Kingston Range, California, Dominic Joel Ombati

Loma Linda University Electronic Theses, Dissertations & Projects

The Neoproterozoic Kingston Peak Formation (KPF) is known for its diamictites interpreted as of glacial origin. The KPF overlies the Beck Spring Dolomite (BSD) that contains microfossils and microbialites. This study aims to test correlation between outcrops and understand the abrupt change from BSD to KPF. It focuses on the basal 4 meters of the KP1 subunit of the KPF as it appears in the Beck Canyon region, Kingston Range, California. We describe and correlate sedimentary rocks at and immediately overlying the contact and analyze the sedimentary structures, textures and sequences. We have found only three sites in the northern …

Taphonomy Of Sediments: Bioturbation In The Triassic Moenkopi Formation In Southwestern Utah, James Vernon Bird Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

Measurement of bioturbation reflects physical and biological processes operating over time and can be used to reveal information about paleo-environments. The purpose of this study was to determine the intensity of bioturbation in Triassic Moenkopi Formation at Hurricane Mesa in Southwestern Utah. This formation is interpreted as having been deposited mostly in large ancient river channels, tidal flats, delta and shallow marine environments. Five stratigraphic sections measured in the Virgin Limestone Member provided the basis for this study. Detailed descriptions and quantification of bioturbation were recorded in each of the sections. Similar treatment was given to additional study sites in …

High-Resolution Correlation Of A Time-Bounded Unit Of The Pisco Formation, Peru, Daniel J. O'Hare

Loma Linda University Electronic Theses, Dissertations & Projects

Correlation of beds in the Pisco Basin across significant distances is problematic and has not yet been effectively achieved. I chose to examine an interval bounded by two time markers, an 40Ar/39Ar-dated white tuff at the base and an 40Ar/39Ar-dated tuff couplet at the top. This interval was chosen because of the continuity and excellent exposure of the tuff beds at six distinct locations in a linear transect 30 km long. Correlation of units was achieved through 40Ar/39Ar dating, lithology, sedimentary structures, and magnetic susceptibility. The vertical and lateral variability in lithology, fossil assemblages, structures, and sequences was examined in …

Soft-Sediment Deformation And Dune Collapse In The Navajo Sandstone, Colby Ford

Loma Linda University Electronic Theses, Dissertations & Projects

The Canyon Overlook Trail of Zion National Park follows an outcrop of Navajo Sandstone, which displays a uniquely well-exposed assemblage of features associated with failure of the lee face of a large eolian dune, and run-out over an expanse of interdune sediments downwind of that bedform. Exposed features include dramatic folds in the interdune succession and a stacked series of thrust sheets incorporating both interdune and overlying dune deposits. Thrust surfaces display consistent strikes, parallel to those of undeformed foresets, and incorporate zones of brittle failure and fluid deformation, including folds overturned in the direction of foreset dip. These features …

Sedimentology Of Marine Vertebrate Burial In The Miocene Pisco Fm., Peru, Monte A. Fleming

Loma Linda University Electronic Theses, Dissertations & Projects

The Miocene Pisco Basin of Peru is known for abundant, well-preserved marine vertebrate fossils (Esperante et al. 2000). Cetacean fossils are particularly abundant—so much so that we were able to locate 10 outcrops containing specimens in cross section, which allowed us to do detailed sedimentological studies of the beds surrounding the whales. We discovered that six of the 10 specimens were buried in channels; the details of the other four burials are too disparate to meaningfully group together in categories. Chapters 3, 4, and 5 describe and discuss the six specimens found in channels, while Appendix A contains descriptions and …

Correlation And Paleoenvironments Above West T9.3 Tuff, Pisco Formation, Peru, Caleb Stanton

Loma Linda University Electronic Theses, Dissertations & Projects

The Pisco Basin is a Cenozoic forearc basin in west central Peru. Though outcrops are well exposed, contain little diagenetic overprint, or complex structural deformation, only rudimentary correlations between outcrops are published and no attempts have been made to define time-bounded subunits. The goal of this study is to develop high resolution-stratigraphy and paleoenvironmental interpretations for a time-bounded unit in the lower part of the Miocene Pisco Formation. In this study, we correlated, mapped, and dated a tuff couplet and associated beds over 25 km2. We measured eight sections that include the tuffs and conducted detailed facies analysis. Sections were …

Paragenesis Of Lacustrine Microbialites In The Upper Wilkins Peak Member, Green River Formation, Wyoming, Bethania Chagas Tosta Siviero

Loma Linda University Electronic Theses, Dissertations & Projects

Microbialites from the upper Wilkins Peak Member were investigated to determine their paragenesis and to help interpret lake chemistry. Two specific microbialite beds were analyzed that are associated with the “layered tuff”. Samples were collected from correlated sections along a NW to SE, 24 km line of section from lake margin towards lake center. XRD, SEM/EDS, and petrographic analysis show differences in diagenesis above and below the layered tuff.

Microbialites below the tuff bed contain some primary calcite with diagenetic dolomite and abundant secondary silicification. Later, dolomite replaces both calcite and quartz. Pores are commonly filled with 20 μm euhedral …

Sedimentology And Paleoenvironments Of The Miocene/Pliocene Pisco Fm., Perú, Cristian R. Carvajal

Loma Linda University Electronic Theses, Dissertations & Projects

The main objective of this research was to understand the sedimentology and depositional environment of the diatomaceous Miocene/Pliocene Pisco Formation in the Ica Valley, Perú. Four stratigraphic sections were studied, sampled and correlated. Field data were integrated with XRD, diatom taxonomy and taphonomy, and thin section analyses to define six facies.

Facies A is composed of diatomaceous siltstone with scour and fill structures formed on a shallow shelf. Facies B was deposited on the transitional zone between the shallow shelf and nearshore where tuffaceous-diatomaceous siltstone and sandstone accumulated. In facies B, lenticular laminations, and flaser, wavy and lenticular bedding record …

Potential Petroleum Reservoir Rocks Of North-Central Oregon, Alfred J. Riddle

Loma Linda University Electronic Theses, Dissertations & Projects

Petroleum explorationists have commonly assumed, based on the presence of volcanic and/or volcaniclastic rock, that regions such as northcentral Oregon do not hold potential as petroleum basins. The typical argument has been that volcanic flows have no effective porosity or permeability and poorly sorted volcaniclastic sediments contain a high percentage of mineralogically unstable grains which are too easily and rapidly altered into clays and zeolites for any significant or effective porosity to be retained.

The objective of this study was to determine if potential petroleum reservoir rocks do exist in north-central Oregon. Through field and laboratory study and by comparing …

Geology Of The Butler Basin, Grant And Wheeler Counties, Central Oregon, Martin R. Aguirre

Loma Linda University Electronic Theses, Dissertations & Projects

The Butler Basin lies along the John Day River in Central Oregon, astraddle the boundary of Wheeler and Grant counties. Strata exposed in this geomorphic basin, formed by an erosionally breached anticline, range in age from Permo-Triassic to Neogene. The basement rocks of the basin are poorly exposed but lithologically similar to the Permo-Triassic Blue Mountains island-arc rocks which crop out to the south and southeast of the basin in the John Day Inlier. Overlying the basement rocks are Early Cretaceous conglomerates with lenses of sandstone and siltstone informally named the "Goose Rock Conglomerate." Pebble and cobble lithologies present in …

Geology And Economic Potential Of The Muddy Ranch Inlier, North-Central Oregon, Mustafa Kamal

Loma Linda University Electronic Theses, Dissertations & Projects

There has been confusion for many years regarding the lithology and age of the rocks exposed in the Muddy Ranch Inlier in north-central Oregon. Taylor (1960) referred to these rocks as metasediments and informally named them the "Muddy Ranch phyllite". My studies indicate the inlier consists of weakly metamorphosed siltstone, mudstone, and less abundant sandstone.

Due to the absence of fossil evidence, it was not possible to determine the age of these rocks. However, from the stratigraphic setting and correlation with similar rocks exposed along structural trend to both the northeast and southwest, rocks of the Muddy Ranch Inlier may …

Paleogeography And Paleoenvironments Of The Lower Unit, Fossil Butte Member, Eocene Green River Formation, Southwestern Wyoming, Roberto Enrique Biaggi

Loma Linda University Electronic Theses, Dissertations & Projects

During Eocene time sediment accumulated in Fossil Lake, in what developed to be a small linear and structurally controlled basin. Fossil Lake was one of several lakes into which the Green River Formation was deposited in Wyoming, Utah and Colorado.

Detailed stratigraphic analysis of the Lower Unit of the Fossil Butte Member revealed a well developed lacustrine sequence south of Fossil Butte, and indicates four major depositional facies: (1) open lacustrine, (2) marginal lacustrine, (3) carbonate mudflat, and (4) marginal fluvio-deltaic. The open lacustrine facies is characterized by kerogen rich to kerogen poor finely laminated micrites , that consist mainly …

Geology In The Vicinity Of The City Of Fossil, Wheeler County, North-Central Oregon, Patrick W. Riseley

Loma Linda University Electronic Theses, Dissertations & Projects

The area of study is located on the north flank of the northeast-southwest trending Blue Mountains Anticlinorium in north-central Oregon. The primary geologic problems investigated were: 1) the age and stratigraphic position of leaf-bearing tufts mapped as Oligo-Miocene John Day Formation but surrounded by andesitic basalts of the Eo-Oligocene Clarno Formation, 2) the age of "olivine basalt" mapped as John Day Formation by some workers but referred to the Clarno Formation by others, and 3) the petroleum potential of the Fossil area.

To resolve these three problems I mapped a 25 square mile area surrounding Fossil at 1 :24,000 scale. …

Rimforest Landslides, San Bernardino Mountains, Southern California, David L. Hanson

Loma Linda University Electronic Theses, Dissertations & Projects

The highly visible erosional scars near the crest of the San Bernardino Mountains just east of Strawberry Peak near the community of Rimforest are active landslides. From at least the 1920's to 1988 the primary activity has been mass wasting by rockfall in highly fractured quartz monzonite. Tension cracks in the adjacent area indicate that active landsliding may be spreading. Landsliding in this area had its origin most likely with the uplift of the San Bernardino Mountains and has continued with periods of active movement associated with heavy precipitation and seismic activity separated by long periods of dormancy. The geomorphology …

Depth Profiles And Soil Textures Of The Vernal Pools Of The Santa Rosa Plateau Preserve, Riverside County, California, Ralph Charles Workman Jr.

Loma Linda University Electronic Theses, Dissertations & Projects

The purpose of this project was to study the edaphic and topographic characteristics of the 13 vernal pools on the Santa Rosa Plateau Preserve, thus documenting the role soil texture plays in vernal pool formation.

Several field and laboratory procedures were used to demonstrate that there is a higher percentage of clay present within vernal pools than in soils outside the margin of the pools, for 11 out of the 13 pools. Statistical tests showed that the percentage of clay was highly significant within the center soil of the pool as compared to the soil outside the margin of the …

Lacustrine Deltaic Deposits Of The Sandstone Tongue Of The Wasatch Formation, Fossil Basin, Wyoming, F. Steve Petersen

Loma Linda University Electronic Theses, Dissertations & Projects

Sedimentary structures and facies relations of the sandstone tongue of the Wasatch Formation in Fossil Basin, Wyoming are interpreted as indicative of a rapidly prograding bird's foot delta. Two upward coarsening siliciclastic sequences that contain bottomset, foreset, and topset beds were studied over an area of approximately 400 square kilometers. Vertical and lateral sedimentary changes within this sequence were documented by the measurement and study of over 35 stratigraphic sections. High and low angle cross-bedded sandstone units within the siliciclastic sequences thicken northward significantly before rapidly thinning and grading into the lacustrine Green River Formation. Field observations. lateral correlation of …

Paleoenvironments Of The Eocene Green River Formation (Laney Member) In The Anvil Wash Area, Southwestern Wyoming, M. Elaine Graham-Kennedy

Loma Linda University Electronic Theses, Dissertations & Projects

The study of abundant conchostracans in the Laney Member of the Green River Formation, Wyoming, has contributed to the resolution of the controversy over the depositional environment of finely laminated sediments. Conchostracans that typically live in ephemeral pools, pulmonate gastropods that require oxygenated water and freshwater ostracods indicate deposition of finely laminated sediments in a well oxygenated, shallow, freshwater lake. Mineralogical evidence indicating that Lake Gosiute was primarily fresh during deposition of the upper portion of the Laney Member includes predominance of calcite over dolomite and the clay composition of diagenetically altered tuffs. The minor amount of dolomite is detrital …

Late Pleistocene Sciurids From Kokoweef Cave, H. Thomas Goodwin

Loma Linda University Electronic Theses, Dissertations & Projects

Three local (Tamias panamintinus, Ammospermophilus leucurus and Spermophilus variegatus) and five extralocal (Tamias minimus, Tamias palmeri, Marmota flaviventris, Spermophilus townsendii, and Spermophilus lateralis) sciurid species (Sciuridae) were identified from the late Pleistocene-early Holocene Kokoweef Cave paleofauna. This fauna was the first documentation of T. minimus, T. palmeri and S. townsendii from the Pleistocene of the Mohave Desert. The 30-ft sedimentary sequence apparently recorded the mid-to late-Wisconsian introduction of S. lateralis into the Kokweef fauna but otherwise documented general taxonomic stability. The ecological diversity of the fauna was consistent with--but did not require--the hypothesis of more equable late Pleistocene climates, and …

Geology And Petroleum Potential Of The Hay Creek Anticline, North-Central Oregon, Stephen I. Wareham

Loma Linda University Electronic Theses, Dissertations & Projects

For many years it has been reported that the core of the Hay Creek Anticline exposes metamorphic rocks of Paleozoic or Mesozoic age. On closer study it was found that these rocks consist of only slightly metamorphosed black to dark grey siltstones and sandstones with less abundant chert pebble conglomerate and recrystallized limestone. The sequence is here informally named "Hay Creek Formation." Calcareous nannofossils recovered and identified from the limestone yielded an age of early to middle Eocene.

The depositional environment of the "Hay Creek Formation" is interpreted to be a submarine turbidite fan. Siltstones were deposited as pelagic rain …

Factors Affecting Epithecal Growth Lines In Four Coral Species, With Paleontological Implications, Jean-Luc Liénard

Loma Linda University Electronic Theses, Dissertations & Projects

The number of epithecal (external) growth lines was surveyed over 124 days for Montastrea annularis growing at different depths (3.5 m to 61 m). There was a significant (P< .01) decrease in the number of lines with depth. Although the linear regression is significant, there is evidence for a logarithmic or quadratic relationship, and more data from greater depths are needed to determine which of these gives a better fit.

The number of growth lines formed during light-dark cycles of 16, 24 and 32 hours were compared for M. annularis, M. cavernosa, Porites astreoides and Tubastrea aurea. The variability among colonies from the same species was in many cases more significant than that among light treatments. This is a serious problem for anyone counting lines in corals, especially from a few specimens; therefore conclusions based on such counts seem hazardous on …

Paleocurrent Analysis Of The Cretaceous Mitchell Formation, North-Central Oregon, Craig A. Sandefur

Loma Linda University Electronic Theses, Dissertations & Projects

Cretaceous sedimentary rocks of north-central Oregon previously referred to as the Hudspeth and Gable Creek formations and recently renamed the Mitchell Formation are potential petroleum source and reservoir rocks. Thus, determining their extent under the cover of Tertiary volcanics is of great importance to future petroleum exploration in the southern half of the Columbia Basin. The direction of sediment transport has been previously studied by several workers with contradicting results and conclusions. The primary objective of this research was to expand the paleocurrent analysis using both macro- and micro-fabric to provide additional evidence of sediment transport direction. This information allows …