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Articles 1 - 9 of 9
Full-Text Articles in Sedimentology
Seismological Applications To Crustal Deformation And Explosion Discrimination, Olumide Adedeji
Seismological Applications To Crustal Deformation And Explosion Discrimination, Olumide Adedeji
Earth and Planetary Sciences ETDs
There are many outstanding questions in seismology and plate tectonics that remain unresolved due to the complexity of seismic wave propagation, fault system evolution, and sedimentary-tectonic interactions. In this dissertation, I analyze seismic and acoustic data to improve event discrimination, understand strain partitioning along a transpressive plate boundary, and investigate the influence of tectonic deformation on sedimentary processes. Using seismic arrays, I assess the detectability of Ground Coupled Airwaves (GCA) generated by shallow borehole explosions and earthquakes, demonstrating that GCA detections are highly dependent on source type, environmental conditions and sensor distribution. Along the Queen Charlotte Plate Boundary, I analyze …
Petrographic And Geochemical Records Of Climate Perturbation In Carbonates From A Perennially Ice-Covered Antarctic Lake, Jared Clance
Petrographic And Geochemical Records Of Climate Perturbation In Carbonates From A Perennially Ice-Covered Antarctic Lake, Jared Clance
Earth and Planetary Sciences ETDs
Carbonate precipitation in perennially ice-covered Lake Fryxell, McMurdo Dry Valleys, Antarctica produces a modern analog for Antarctic paleolake carbonates. Lake Fryxell contains a steep oxycline in the photic zone, where dissolved oxygen falls from supersaturation to zero. In the lake’s benthic microbial mats, oxygen concentrations are higher than in the water column due to microbial photosynthesis. These mats contain carbonate cements that precipitated in a discrete episode from mat pore waters. Precipitation continued through seasonal fluctuations in oxygenation, demonstrated by variable concentrations of oxidized and reduced manganese and iron within carbonates. Carbonates precipitated out of isotopic equilibrium with the lake …
The Morphology And Evolution Of Transverse Aeolian Ridges On Mars, Timothy Paul Nagle-Mcnaughton
The Morphology And Evolution Of Transverse Aeolian Ridges On Mars, Timothy Paul Nagle-Mcnaughton
Earth and Planetary Sciences ETDs
Transverse aeolian ridges (TARs) are enigmatic and largely relict bedforms on the surface of Mars. TARs are sparsely distributed but common on Mars, but their history, preservation, and past role in the sediment cycle is not well understood. First described in 2003, and detailed extensively in 2008, our study of TARs has been narrowly focused in the last decade, with more and more research noting their presence, but little investigation of the features themselves. Recent work has mostly focused on identifying Terran analogues for TARs, but TARs remain largely a unique Martian feature. In this manuscript, I clarify and refine …
Diversity – Independent Factors Predict Elevated Extinction Rates, Dustin Perriguey, Corinne Myers, Jason Moore, Louis Scuderi
Diversity – Independent Factors Predict Elevated Extinction Rates, Dustin Perriguey, Corinne Myers, Jason Moore, Louis Scuderi
Earth and Planetary Sciences ETDs
Multiple linear regression was used to determine the relationships between diversity-independent factors (i.e., abiotic, climatic) 2, 5, and 10 Myrs-prior to the most elevated Phanerozoic extinctions. We constructed five abiotic variables from Phanerozoic proxy records1–5 to compare to extinction rates: mean temperature, temperature instability, carbon cycle instability, continental weathering rates, and habitat instability. All three models were statistically significant (P < 0.05) and explained > 70% of the variation in Alroy’s6 three-timer generic extinction rates. However, the 2 Myr-prior model explained the most variance in extinction rates and had the most predictive power, based on adjusted and predictive R2 (~ 72% and 41%, respectively). Carbon …
Interpreting Amalgamation Processes Of A Fluvial Sandstone Of The Nacimiento Formation In The San Juan Basin, New Mexico, Keely Elizabeth Miltenberger
Interpreting Amalgamation Processes Of A Fluvial Sandstone Of The Nacimiento Formation In The San Juan Basin, New Mexico, Keely Elizabeth Miltenberger
Earth and Planetary Sciences ETDs
Outcrop studies of fluvial sand bodies are important for the study of fluid transport and storage capabilities because the deposits are heterogeneous. 3-D photogrammetry was used to evaluate the amalgamation processes of a multi-storey sheet sandstone in the San Juan Basin, NM. The Angel Peak member was deposited in the proximal-medial transition of a distributive fluvial system by a meandering river during the Paleocene. Within the study area, amalgamation occurred by avulsion and reoccupation of channel-belts to produce five storeys of the multi-storey sheet sandstone. Within each storey is evidence of processes that are internal to a channel-belt, such as …
Eutherian Biogeography During The Puercan North American Land Mammal Age (Paleocene, Earliest Danian): Problems And Potential Solutions, Jason Sterling Silviria
Eutherian Biogeography During The Puercan North American Land Mammal Age (Paleocene, Earliest Danian): Problems And Potential Solutions, Jason Sterling Silviria
Earth and Planetary Sciences ETDs
The Puercan North American Land Mammal Age (NALMA) is the earliest major North American terrestrial biochron of the Cenozoic era, spanning roughly the first one million years of the Paleogene period (Paleocene epoch, Danian stage; ~66.04-65.12 Ma). It is typified by the explosive ecomorphological diversification of the mammalian clade Eutheria (particularly our subclade, Placentalia), following the annihilation of non-avian dinosaurs and “archaic” mammal groups during the Cretaceous/Paleogene (K-Pg) mass extinction event. The spatiotemporal mode and tempo of Puercan eutherian diversification has long been the subject of debate, with disagreements over biogeographic zonation. The traditional model – based largely on well-sampled, …
Sedimentology And Stratigraphy Of Core Stl14: An Early Pleistocene-To-Present Paleoclimate Archive From Stoneman Lake, Arizona, Spencer Staley
Sedimentology And Stratigraphy Of Core Stl14: An Early Pleistocene-To-Present Paleoclimate Archive From Stoneman Lake, Arizona, Spencer Staley
Earth and Planetary Sciences ETDs
An 80 m lacustrine sediment core (STL14) from Stoneman Lake, Coconino County, Arizona, contains a sedimentary sequence of at least 1.5 million years, chronicling the complete history of basin infill and recording an extensive and high-resolution archive of climatic and hydrologic fluctuations. Lake levels in this small, internally-drained catchment are sensitive to changes in regional hydrologic balance. Consistent groundwater inflow, even during regionally dry episodes in the lake’s history, has prevented complete desiccation of the lake and sustained continuous lacustrine deposition except for one soil horizon. Multiproxy analysis of sedimentological indicators including lithofacies, color, wet bulk density, magnetic susceptibility, preliminary …
Birth And Evolution Of The Rio Grande Fluvial System In The Last 8 Ma:Progressive Downward Integration And Interplay Between Tectonics, Volcanism, Climate, And River Evolution, Marisa N. Repasch
Earth and Planetary Sciences ETDs
The Rio Grande-Rio Chama (RG-RC) fluvial system has evolved dramatically over the last 8 Ma, undergoing channel migrations, drainage capture and integration events, volcanic damming, and carving and refilling of paleocanyons. Volcanism concurrent with the development of the river system provides a unique opportunity to apply multiple geochronometers to the study of its incision and drainage evolution. This paper reports 19 new 40Ar/39Ar basalt ages and 19 detrital mineral samples (zircon and sanidine) collected from RG-RC alluvium overlain by dated basalt flows in the context of a compilation of published 40Ar/39Ar basalt ages. The …
Geology Of The Southern Ladron Mountains, Socorro County, New Mexico, E.A. Noble
Geology Of The Southern Ladron Mountains, Socorro County, New Mexico, E.A. Noble
Earth and Planetary Sciences ETDs
The Ladron Mountains are in a fault-block range consisting in large part of Pre-Cambrian rocks. They are flanked on the west by Paleozoic sediments and elsewhere by Tertiary and Quaternary deposits. The Pre-Cambrian rocks of the southern Ladron Mountains consist of a thick sequence of quartzite and schist which has been granitized by a sub-adjacent intrusion to such a degree that only remnants of unaltered quartzite and schist remain, the remainder of the rocks being largely paragneiss and para-granite. The nature of the intrusion is not known, but it is suggested that it may have been at least partly formed …