This study integrates detailed mapping of Tertiary deposits along the divide between the lower Bear River basin and the Cache Valley basin with several other techniques to generate a depositional model, define extension-related structures, and compile a geologic history for this part of the northeastern Basin and Range province. The study area is situated along the topographic divide between Box Elder and Cache Counties, Utah, from the Wellsville Mountains north almost to Clarkston Mountain. These ranges are cored by folded and thrusted Paleozoic rocks. They are bound on the west by normal faults of the Wasatch fault zone and on the east by the West Cache fault zone. Between these two fault zones, poorly consolidated Tertiary deposits of the Wasatch Formation and Salt Lake Formation overlie Paleozoic rocks in the foothills and low divide between the north-trending ranges. The Miocene to Pliocene Salt Lake Formation accumulated above non-tuffaceous conglomerates of the Paleocene to Eocene Wasatch Formation, up to 0.5 km thick in the Wellsville Mountains, but thin or absent northward. The Salt Lake Formation in the study area consists of an apparently non-tuffaceous lower conglomerate member, up to 0.5 km thick in the Wellsville Mountains, and a widespread younger tuffaceous and lacustrine member, at least 1 km thick. The traditional names of Collinston Conglomerate and Cache Valley Member were used for these two lithologies. The Cache Valley Member was further subdivided into a local tuffaceous basal conglomerate, a widespread tuffaceous subunit, and an overlying oolitic subunit. Normal faults in the study area comprise three groups. North-striking normal faults are the youngest, and include major range-bounding faults. East-striking normal faults are less numerous, and are cut by the north-striking faults. The southwest-dipping low-to moderate-angle Beaver Dam fault separates the Cache Butte Divide and Junction Hills from the Wellsville Mountains. It may be unique within the area of study, and may comprise a newly identified segment of the Wasatch fault zone. Most of its displacement appears to pre-date the late Miocene, at the time that previous authors have suggested for the onset of Basin-and-Range normal faulting.

Two basalt flows and an andesite fissure eruption occur in the Rozel Hills - Black Mountain area in Box Elder County, Utah. Both basalt flows are aphanitic, and contain olivine, plagioclase, augite, and opaque oxides. They may be distinguished both chemically and on the basis of their textures. Unit 2 basalt is finer grained, and appears to be associated with a fault in the Black Mountain area. Chemically, it is similar to high-iron lavas in the Craters of the Moon, Idaho area. It has higher alkali, total iron, and titanium contents that Unit 1 basalt. Unit 1 basalt is similar to other tholeiitic basalts in the Basin and Range province. It is coarser-grained and has higher silicon, magnesium, aluminum, and calcium contents than Unit 2 basalt. While the basalts have characteristics of alkali-olivine basalts, such as absence of calcium-poor pyroxene, and a high alkali to silica ratio, both units are hypersthene- and olivine-nonnative and classified as olivine tholeiites. Subsurface basalt in the area appears to represent both lava types, but extensive alteration makes comparison difficult. Andesite from the area is aphanitic, and contains plagioclase, orthopyroxene, and opaque oxides. Temperatures of equilibration calculated from co-existing magnetite and ilmenite range f rom 1148°C to 745°C for basalt. Temperatures calculated from co-existing olivine and clinopyroxene range from 1009°C to 994°C. While the two basalt units cannot be related by fractional crystallization at surface conditions, some parent - daughter relations are likely within each unit, and the andesite is most likely a differentiation product of Unit 1 basalt. Partial melting of pyrolite and spinel lherzolite mantle compositions to produce Unit 1 and Unit 2 basalts was investigated. Since no unique temperature and pressure of equilbration for these melts and residu~l material from each mantle type was found, it is concluded that partial melting of a mantle of pyrolite or spinel lherzolite composition did not produce these lavas. Unit 2 basalt may be derived from Unit 1 basalt by fractionation of high pressure (8 kb) phases. This mechanism, similar to that proposed for the Craters of the Moon - Snake River Plain system, may account for an evolved basalt (Unit 2) with a lower silica content than a less differentiated basalt (Unit 1).

Most people are at least aware that, in the past, companies that owned mines, lumber mills, and other large-scale industrial projects in isolated areas also ran company towns. For many people, such towns conjure up images miserable working conditions, exploitative company stores, and inadequate shacks for most workers, while managers live in relative luxury up on “snob knob.” Most people are also fairly certain that such towns, at least in the United States, died out about the same time as the horse and buggy. Several industries in Wyoming, however, continued to support company towns through the end of the 20th century, with one such town surviving into the early 2000s. This project looks at two of these towns supported by the uranium mining and milling industry that dominated central Wyoming’s economy for about 30 years starting in the mid-1950s. These towns, Gas Hills and Jeffrey City, along with Wyoming’s other modern company towns represent a new era in the history of these communities. Furthermore, they actually had many advantages for inhabitants, companies, and the local economy, especially compared to a small conventional community located near a resource boom. Often, and in contrast to the towns in this thesis, conventional towns must scramble to meet the demands of a massive migration, only to be left with unpaid bonds when the resource dries up or becomes no longer profitable.

No description available.

Three paleo-environments were studied. The first project concerned the Manson Impact and the effect of the Black Hills on the resulting fall-out from this asteroid strike. Samples of the Crow Creek Member were taken east of the Black Hills in Nebraska and South Dakota and samples from the Red Bird Member were taken from the west, in Wyoming. These samples were examined for chemical weathering, soot, shocked quartz, and fossils. The Crow Creek samples had shocked quartz (indicative of an impact), severe chemical weathering, soot, and evidence of tsunamis. There were few calcareous fossils. The Red Bird showed no signs of chemical weathering, a distinct absence of soot and shocked quartz and an abundance of fossils. These results indicate that the Black Hills were large enough to pose an atmospheric and oceanic barrier to the effects of the Manson Impact. The second project dealt with dinosaur eggs which were found in Montana. The eggs were examined and subjected to Computed Tomography Scans. The egg-shell, matrix, and volcanic ash were studied. The egg-shell was found to be from an undescribed oolithic species, and revealed that a transgressive event transpired after the eggs had fossilized. The matrix revealed that the eggs were laid in a flood-plain. The ash revealed a high amount of tungsten and yielded a high percentage of potassium for future dating. The eggs themselves revealed that intact embryos were within. This project has provided information on dinosaur nesting behavior. In the third project corals were examined to determine the usefulness of sampling different architectural structures for evaluating environmental proxies. Coral was collected at the Verde Reef. The different architectural structures were sampled using SIMS, and LA-ICP-MS to selectively sample the small architectural structures. Oxygen isotope ratios and elemental: calcium ratios were compared among the different structures. It was found that dissepiments intake isotopic oxygen and elements at different rates than other structures. This has an impact in sampling corals for environmental proxies, but, because of the very small amount of mass contained in the dissepiments that bulk analyses would not be significantly affected.

Archaeological surveys using the subsurface testing method known as “shovel-testing” have been performed sporadically across the Bienville National Forest in central Mississippi. However; no research-oriented analysis has ever been performed for this area. The Bienville National Forest is located primarily in two physiographic regions: the Jackson Prairie and the Southern Pine Hills. These two regions are distinctly different in topography, soils, and vegetation. No settlement pattern study has been performed in the Jackson Prairie and it has been viewed as an area of low probability. Soils in this region are often heavy clays with high shrink/swell capabilities and poor drainage. In this thesis, I attempt to construct an initial analysis by looking at the duration of occupations and their placement in the landscape through time in order to determine whether the Jackson Prairie played any important role in the choice of habitation locations by prehistoric populations.

A long-standing question in ecology is understanding how the environment structures species occupancy in space and time. Specifically, identifying associations between environmental drivers - climate and land cover - and species occupancy is crucial to predicting species distributional dynamics in the future. Over the last century, research on the abiotic drivers of species occupancy has largely focused on temperate regions. Tropical mountain ecosystems harbor extraordinary levels of diversity and face some of the highest anthropogenic pressures of climate and land cover change. Yet, such regions have remained historically understudied. Bird species, due to their sheer diversity and occurrence across climatic zones and land cover types, are an ideal model for understanding how climate and land cover structure occupancy in space and time. The goal of this dissertation is to disentangle spatial and temporal associations between environmental drivers - climate and land cover - and bird species occupancy along a tropical montane gradient. I use an integrative approach that relies on citizen science, historical ecology, and bioacoustics to study bird communities in the Western Ghats biodiversity hotspot of southern India. In Chapter 1, we used observations from the world’s largest citizen science database, eBird, to ask how contemporary climate and land cover are associated with bird species occupancy across the Nilgiri and the Anamalai hills of the Western Ghats. We show that the occupancy of several forest specialist birds was negatively associated with temperature seasonality, highlighting narrow thermal niches for such species. We also show that a small number of generalist bird species are positively associated with human-modified land cover types. In Chapter 2, we combined colonial-era and modern datasets on bird species observations and land cover to ask how a century of landscape change across the Nilgiri hills has impacted bird communities. Between 1848 and 2017, 75% of grassland habitat across the Nilgiri hills was lost toward timber plantation and cash crop expansion. Such drastic declines in grassland habitat have resulted in declines in species persistence and relative abundance of grassland specialist birds over the last century. As a result, the functional trait space has undergone biotic homogenization. In Chapter 3, we ask if the reversal of landscape changes significantly affects bird communities. Using passive acoustic monitoring, we examined the impacts of ecological restoration on bird communities and other vocalizing fauna along a gradient of forest regeneration (consisting of actively restored, naturally regenerating, and mature benchmark sites) in the Anamalai hills. Encouragingly, we show that the bird community composition of actively restored sites is transitioning toward mature benchmark sites. However, when we moved beyond birds, we found that vocalizations at higher frequencies (> 12 kHz) were largely missing from actively restored and naturally regenerating sites, while the same frequency space was occupied in mature benchmark sites. Taken together, we find that climate and land cover are key determinants of bird species occupancy in the Western Ghats, and in a globally changing world, conservation interventions such as ecological restoration along with the preservation of naturally occurring land cover types are key to sustaining montane avifauna in the long run.

Though almost thirty years have passed since the 1991 Tunnel Fire, the wildfire hazard is still present in the Oakland Hills. This study was conducted to determine if the vegetation in the Oakland Hills had reverted back to fuel conditions that contributed to the Tunnel Fire, examine how the fire hazard has changed since 1991, and evaluate planned wildfire mitigation. The goal was to determine how fuel conditions have changed since 1991 and compare potential fire behavior to that of the Tunnel Fire. Additionally, the study examined the effectiveness of the mitigation actions described in the East Bay Regional Park District’s Wildfire Hazard Reduction and Resource Management Plan on lowering extreme fire behavior. Through the use of remote sensing, historical aerial imagery, satellite imagery, and Landsat imagery the 1991 and 2018 fuel conditions were analyzed. ArcGIS Pro and FlamMap 6 were used to compare hectares of fuel and changed in fire behavior between the two year. Mitigation actions were modeled with FlamMap 6 and ArcGIS Pro and fire behavior was compared between untreated conditions and post treatment conditions. The vegetation in the Oakland Hills, in the absence of fire, returned to a mature state, similar to the 1991 conditions. However, there was a reduction in the overall hectares of fuel model 147 in 2018. Modeled fire behavior indicated an overall reduction in extreme fire behavior when comparing 1991 to 2018. This reduction varied on a park level with each park performing differently. When modeled, mitigation was able to lower extreme fire behavior across the landscape but success varied on an individual park basis. In conclusion, should ignition occur presently, under foehn wind conditions, a fire would still exhibit very extreme behavior with a high potential for catastrophic loss, and implantation of planned mitigation measures may be able to lower the degree of extreme fire behavior.

No description available.

No description available.