Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

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 …

An Avian Botulism Epizootic Affecting A Nesting Site Population Of Presbyornis : On A Carbonate Mudflat Shoreline Of Eocene Fossil Lake, V. Leroy Leggitt

Loma Linda University Electronic Theses, Dissertations & Projects

The shorebird-duck mosaic bird, Presbyornis, is best known from the Eocene Green River Formation where it often occurs in local monospecific bonebeds, suggestive of mass mortality events. The sedimentology, paleontology, taphonomy, XRD mineralogy, and the carbonate stable isotope signature (δ¹⁸O) of one of these bonebeds was studied on the southern margin of Eocene Fossil Lake.

A series of 408 standardized radiographs were used to construct the first large scale radiograph aided taphonomic map of a vertebrate fossil quarry (3,874 bones were recorded in 11.5 m²). A small group of 100 bones (including a complete skull …

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 …

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 …

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 …

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 …