Paleomagnetic directions have been obtained from 190 Middle Miocene (12-20 Ma) mafic volcanic flows in 16 mountain ranges in the Mojave-Sonora desert region of western Arizona and southeastern California. These flows generally postdate Early Miocene tectonic deformation accommodated by low-angle normal faults but predate high-angle normal faulting in the region. After detailed magnetic cleaning experiments, 179 flows yielded characteristic thermal remanent magnetism (TRM) directions. Because of the episodic nature of basaltic volcanism in this region, the 179 flows yield only 65 time-distinct virtual geomagnetic poles (VGPs). The angular dispersion of the VGPs is consistent with the angular dispersion expected for a data set that has adequately averaged geomagnetic secular variation. The paleomagnetic pole calculated from the 65 cooling unit VGPs is located at 85.5°N, 108.9°E within a 4.4° circle of 95% confidence. This pole is statistically indistinguishable (at 95% confidence) from reference poles calculated from similar-age rocks in stable North America and from a paleomagnetic pole calculated from similar-age rocks in Baja and southern California. From the coincidence of paleomagnetic poles from the Mojave-Sonora and adjacent areas, we can conclude that: (1) vertical-axis tectonic rotations have not accompanied high-angle normal faulting in this region; (2) there has been no latitudinal transport of the region since 12-20 Ma; and (3) long-term nondipole components of the Miocene geomagnetic field probably were no larger than those of the recent (0-5 Ma) geomagnetic field. In contrast, paleomagnetic data of other workers indicate vertical-axis rotations of similar-age rocks in the Transverse Ranges, the Eastern Transverse Ranges, and the Mojave Block. We speculate that a major discontinuity in the vicinity of the southeastward projection of the Death Valley Fault Zone separates western areas affected by vertical-axis rotations from eastern areas that have not experienced such rotations.

This study was conducted by Cultural Systems Research, Incorporated (CSRI) for Applied Conservation Technology, Incorporated (ACT). This study has been conducted to determine which Native American groups traditionally used the area through which the Intermountain Power Agency (IPA) proposes to construct the California portion of the Intermountain -Adelanto Bipole Transmission Line, a component of the Intermountain Power Project (IPP); to determine what value these groups place on cultural resources which might be disturbed by the construction of the transmission line and associated structures; and to convey their recommendations for the mitigation of these impacts. The results of the study are intended to enable the IPA to comply with requirements of various state and federal agencies with respect to this component of the IPP. The study area for this project was an area measuring 100 feet (30 m) on either side of the center line of the right -of -way for the proposed transmission line that was proposed to run from the California- Nevada border to the vicinity of Victorville, California. The Native American groups who traditionally used the area through which the proposed IPP right -of -way would pass include the Southern Paiute, the Mojave, the Vanyume /Serrano, and the Kawaiisu. Members of various other groups have travelled through the area, and used it from time to time.

The speaker of The Desert Survival Guide is seeking to reconcile his own disconnection, from the natural world, the cosmos, his family, and from his sense of his own humanity. The poems in The Desert Survival Guide are a healing ceremony, to come to a place of acceptance regarding the loss of my father. The semi-autobiographical speaker of these poems has lost the immediate physical presence of his father in his life but still retains a deep memory imprint of the father and an unresolved need to process the absence of the father. He is gradually establishing a new connection to the land on which his father lived out his life and was buried. Impressions of his father bloom out from the geologic features of the landscape, the natural flora and fauna, all a realm of immediate waking dream. The speaker is something of an Orphean Shaman; he wanders the landscape howling his pain and loss, his love, his passions, as Orpheus did his songs. He seeks to pierce through the veil of death in order to reconcile the loss of his loved ones; he seeks to go beyond the human created world into the mystic experience of the desert through the power of utterance and by honoring virile animal familiars. He journey’s to the beyond, for much the same purposes as the shaman, a purpose common to poets, mystics, and scientists, to see beyond immediate knowing. He follows the most primal of human directives, the need to understand and communicate the experiences of his life which have struck him with great intensity.

A series of severe and prolonged droughts occurred throughout the Northern Hemisphere between approximately 1150 BP to 600 BP. This phenomenon is referred to as the Medieval Climatic Anomaly and has been shown to have differentially impacted various regions of the world. Previous studies have suggested causal links between the Medieval Climatic Anomaly and observed culture change. The goal of this study was to examine the Antelope Valley region of the Mojave Desert for evidence of impacts on human populations related to the Medieval Climatic Anomaly. To achieve this goal, a sample selection of archaeological sites was chosen from lands within Edwards Air Force Base. These sites represented occupations which occurred immediately before, during, and after the Medieval Climatic Anomaly. Site assemblages were analyzed and compared by cultural period, with cross-comparisons made of artefactual and ecofactual constituents. Site densities and areal extents were also examined and compared. These analyses showed the emergence of trends concurrent with the introduction of the Medieval Climatic Anomaly. The data supports the hypothesis that humans who populated the Antelope Valley region of the Mojave Desert during this period may have engaged in population aggregation, with a tethered nomadism subsistence strategy. The data also shows evidence that upon the amelioration of the environment after the Medieval Climatic Anomaly, site characteristics within the region saw a significant shift. While the evidence generated by this study does suggest a link between climatic change experienced during the Medieval Climatic Anomaly and change observed within the archaeology of the Antelope Valley, it does not suggest climate as a sole, or even primary, causal factor. Rather, the intent of this study was to identify one possible variable responsible for observed change that occurred in the region. With this in mind, the Medieval Climatic Anomaly was found to have been significant enough to have either directly or indirectly impacted the prehistoric occupants of the study region.

For more than two centuries, humans have been spewing “greenhouse gases” into the atmosphere through the burning of fossil fuels, deforestation, and the development of land, causing the planet’s surface temperature to increase at an accelerated rate. Climate change is one of the most pressing issues that the world is facing today, and in order to combat the effects of climate change, it is necessary to adopt the use of more renewable technology, namely solar energy. The United States' best region for solar development is the Mojave Desert, and many large-scale projects are being built or proposed to be built in the area. However, the deployment of solar technology in the Mojave Desert comes with significant ecological, socioeconomic, and political impacts. This paper is intended to provide an overview of the issues surrounding solar development in the Mojave Desert.

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 16, 2010). Includes bibliographical references. Also issued in print.

Barium is a relatively abundant element in the crustal environments, Ba quantities can range from anywhere between 200ppm to 900ppm. Most common forms of Ba-minerals found in the environment are barite (BaSO4), witherite (BaCO3) and hollandite (Ba2Mn8O16). Ba is a useful element; it is used in various industries as a component in drilling fluids, in medical research and in manufacturing of various substances such as glass, ceramics, printing paper etc. However high quantity of Ba can be potentially toxic for the human body and can impair plant growth. It is therefore, important to review the terrestrial biogeochemical cycle of Ba, which is less studied and less understood than the oceanic biogeochemical cycle of Ba. Additionally, terrestrial systems face a diverse climate and are not as stable as the oceanic systems. Due to this the terrestrial biogeochemical cycle of barium is continuously changing and is more dynamic than the oceanic cycle. By studying one part of the cycle, i.e. the interaction of Ba in the atmosphere with the geosphere in the Mojave desert, NV, I propose a study to test the hypothesis that occurrence of, Ba-mineral, barite, in desert soils is mainly driven by dust flux. The proposal includes methodology for dust collection, sample analysis using XRF, XRD and SEM.EDS techniques and potential budget and timeline. Evidence supporting this claim would suggest that dust transports such minerals, affects the soil chemistry of desert soils and the interaction of various terrestrial systems.

Geoarchaeology -- Pre-Clovis archaeology -- Site search strategies.

No description available.

Human activities are increasing the size, frequency and severity of disturbance across earth’s ecosystems including deserts. Exotic annual grasses have altered fire regimes by increasing the size, frequency, and severity of fires in these systems. Invertebrates make up a large proportion of ecosystem diversity, provide a wide range of ecosystem functions, and are good indicators of ecosystem function and resilience. Ants are particularly good indicators of ecosystem stability. The ability of rodents to modify plant community structure post-fire, could result in rodent communities having important indirect effects on invertebrate communities. In chapter 1 we report changes in ant forager abundance and diversity with fire and rodent treatments over a three year period in the Great Basin. We found that while rodents had significant effects on the plant community in burned plots, this did not affect the ant community. Fire, however played a significant role in determining ant species richness and Shannon’s diversity index. Ant richness and diversity were reduced in burned areas compared to unburned areas. Total ant forager abundance was unaffected by fire, however, the abundance of the most common ant species, Pogonomyrmex occidentalis, increased in burned areas. The overall abundance of the other species was reduced in burned areas. We saw increases in the densities of P. occidentalis mounds in burned areas, but the average size of those discs decreased. The total area occupied by P. occidentalis mounds remained equal between burned and unburned plots. In chapter 2 we compare the abundances of different groups of invertebrates, as well as the abundances and diversity of the ant communities, between fire and rodent treatments. We then compared how those responses differed between sites in the Great Basin and Mojave deserts. In this study, we found that the abundances of most invertebrate groups remained unaffected by fire and rodent treatments. In the Great Basin, however, the abundance of flying-foragers was reduced in burned areas. At both locations, ant species richness and Shannon’s diversity were reduced in burned areas. Species richness and Shannon’s diversity were negatively correlated with invasive plant cover at both sites, and invasive plant cover was positively correlated with fire. The loss of diversity can spell losses in important ecosystem functions, and invasive grass fire cycles threaten to make these losses permanent.