Physical Sciences and Mathematics Commons^™

Geomorphic History Of The Grand Staircase Region Of The Colorado Plateau: Understanding Arroyo Cut-Fill Dynamics, Erosion Rates, And Wildfire, Kerry E. Riley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Most streams in the southwestern United States do not flow all year, and given their delicate balance of sediment and water flow, they are sensitive to climate change. At the turn of the 20th century, many streams in the Southwest rapidly incised into their floodplains, forming arroyos with a channel entrenched into near-vertical channel banks mostly composed of sand and mud. This dissertation investigates past changes in watersheds draining the Grand Staircase region in southern Utah with the goal of understanding how changes in climate and sediment influence these types of streams. Results show sediment supply is highly variable across …

Pleistocene Relative Sea Levels In The Chesapeake Bay Region And Their Implications For The Next Century, Benjamin D. Dejong, Paul R. Bierman, Wayne L. Newell, Tammy M. Rittenour, Shannon A. Mahan, Greg Balco, Dylan H. Rood

Geosciences Faculty Publications

Today, relative sea-level rise (3.4 mm/yr) is faster in the Chesapeake Bay region than any other location on the Atlantic coast of North America, and twice the global average eustatic rate (1.7 mm/yr). Dated interglacial deposits suggest that relative sea levels in the Chesapeake Bay region deviate from global trends over a range of timescales. Glacio-isostatic adjustment of the land surface from loading and unloading of continental ice is likely responsible for these deviations, but our understanding of the scale and timeframe over which isostatic response operates in this region remains incomplete because dated sea-level proxies are mostly limited to …

A Middle To Late Holocene Record Of Arroyo Cut-Fill Events In Kitchen Corral Wash, Southern Utah, William M. Huff

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Arroyos are steeply entrenched channels that form by incision into weakly consolidated valley-fill alluvium. This study attempts to offers clues into the processes behind their formation by dating arroyo sediments using luminescence and radiocarbon techniques. The importance of understanding arroyo formation is due to a possible linkage with decadal to centennial-scale climate fluctuations. In the 1800s and early 1900s, many of the shallow, perennial streams throughout southern Utah that used for a variety of agricultural and domestic uses were incised up to ~30 m into their alluvium by frequent and high-magnitude flood events. The economical and ecological effects of these …

Geologic Mapping, Alluvial Stratigraphy, And Optically Stimulated Luminescence Dating Of The Kanab Creek Area, Southern Utah, Michelle Carlene Summa

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

At the turn of the century, Kanab Creek incised 30-meters into its alluvium, leaving behind fluvial terraces and thick basin fill sediments exposed along arroyo walls. Research objectives were to determine the timing and causes of past valley-filling and arroyo-cutting episodes along a 20 km-long reach of Kanab Creek in southern Utah. Fluvial deposits were mapped at the 1:12,000 scale and sediments were described and dated using Optically Stimulated Luminescence (OSL) and radiocarbon dating.

The Kanab Creek valley can be divided into a narrow, upper terraced reach and a broad lower basin fill reach near Kanab, Utah. The most prominent …

Native Or Introduced? Fossil Pollen And Spores May Say. An Example From The Azores Islands, Jacqueline F.N. Van Leeuwen, Hanno Schäfer, W. O. Van Der Knapp, Tammy M. Rittenour, Svante Björck, Brigitta Ammann

Geosciences Faculty Publications

Aim: Among the various possible approaches to assess whether a species is native or introduced, the analysis of subfossil pollen and spores from natural archives is a valuable tool. Requirements include a sufficiently high taxonomic resolution of the pollen morphology, as well as sufficient temporal and spatial resolution. The aim of this study is to show the usefulness of this method in solving whether the taxon is native or introduced.

Location: The results are derived from two islands of the Azores: Flores and Pico. Methods: Analysis of pollen and spores in lake sediments; radiocarbon dating of the studied sediments.

Results: …

Holocene Tephrostratigraphy, Southern Kenai Peninsula, Lower Cook Inlet, Alaska, Kathleen J. Lemke

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis describes the results of a study of 33 tephra layers found within two peat sections near Anchor Point and Homer, Alaska, on the lower Kenai Peninsula. Numerous lower Cook Inlet volcanoes have been active through the Holocene. Tephra layers found at these two sites provide a partial record of their eruptive activity. The hazards that accompany this activity have increased as populations and commercial activities expand and air traffic over the region increases. The tephras analyzed for this study provide an initial geochemical database for the lower Cook Inlet volcanoes. The database is available in electronic format at …

Sedimentological And Foraminiferal Characterization Of A Holocene Island Slope (130-240m), North Jamaica, Craig V. Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent carbonate sediments from (133-236m) on the northern Jamaican island slope are significantly different from shallower reef zones (l-70m) in grain constituents, textural parameters, and foraminiferal assemblages. The island slope sediment is dominated by coral fragments, calcareous algae, Halimeda plates, and foraminiferal tests. The sediment is characteristically poorly-sorted, nearly-symmetrically skewed, and mesokurtic, with a mean grain size in the fine sand range. Mineralogically, the sediment is predominantly aragonite (66%) and high-Mg calcite (22%), with some calcite (8%), and minor amounts of clays and other insoluble minerals (4%).

Q-mode cluster analyses of sediment constituents, textural parameters, and foraminiferal species and larger …