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The Antiquity Of The Sahara Desert: New Evidence From The Mineralogy And Geochemistry Of Pliocene Paleosols On The Canary Islands, Spain, Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Juan F. Betancort, Alejandro Lomoschitz
The Antiquity Of The Sahara Desert: New Evidence From The Mineralogy And Geochemistry Of Pliocene Paleosols On The Canary Islands, Spain, Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Juan F. Betancort, Alejandro Lomoschitz
United States Geological Survey: Staff Publications
The Sahara is the largest warm desert in the world, but its age has been controversial, with estimates ranging from Miocene to Holocene. Mineralogical and geochemical data show that paleosols of Pliocene to mid- Pleistocene age on Fuerteventura and Gran Canaria in the Canary Islands have developed in part from inputs of dust from Africa. These paleosols contain quartz and mica, minerals that are abundant in African dust but are rare in the basaltic rocks that dominate the Canary Islands. Trace elements with minimal mobility, Sc, Cr, Hf, Th, and Ta as well as the rare earth elements, show that …
Past, Present, And Future Arctic Climate And National/Community Risk Assessment, Jeff Auger
Past, Present, And Future Arctic Climate And National/Community Risk Assessment, Jeff Auger
Electronic Theses and Dissertations
The Arctic is warming at a rate nearly double that of the global average. The enhanced rate of warming impacts weather and climate across the Northern Hemisphere. As the meridional (south to north) thermal gradient weakens, the middle-latitude westerlies are expected to slow and become “wavier” increasing heat and moisture advection to higher latitudes. A quasi-stationary ridge-trough system of the jet stream increases chances for droughts, floods, heatwaves, and cold spells. These impacts have already been observed as North American forest fires and early or extended Great Lake ice out. It is more important than ever to understand how the …
Wildfires In The Northeastern United States: Evaluating Fire Occurrence And Risk In The Past, Present, And Future, Daniel R. Miller
Wildfires In The Northeastern United States: Evaluating Fire Occurrence And Risk In The Past, Present, And Future, Daniel R. Miller
Doctoral Dissertations
Climate change is one of the most complex and challenging issues facing the world today. A changing climate will affect humankind in many ways and alter our physical environment, presenting ethical challenges in how we respond. The impact of climate change will likely be exacerbated in heavily populated regions of the planet, such as the Northeastern United States (NEUS). The NEUS is comprised of complex, sprawling urban centers and rural regions, both of which are vital to the economic and cultural character of the region. Furthermore, both urban and rural areas in the NEUS contain communities that have been historically …
A Diatom Proxy For Seasonality Over The Last Three Millennia At June Lake, Eastern Sierra Nevada (Ca), Laura Caitlin Streib
A Diatom Proxy For Seasonality Over The Last Three Millennia At June Lake, Eastern Sierra Nevada (Ca), Laura Caitlin Streib
Theses and Dissertations--Earth and Environmental Sciences
The Sierra Nevada snowpack is vital to the water supply of California, the world’s sixth largest economy. Though tree ring and instrumental records show the dramatic influence of environmental change on California’s hydroclimate over the last millennium, few proxy archives assess winter precipitation variability farther back in time. Here, we use diatoms from a ~3,200 yr. old sediment core to reconstruct the paleolimnology of June Lake, a hydrologically closed glacial lake in the eastern Sierra Nevada. We test the hypothesis that limnologic and climatic changes control diatom assemblages at June Lake. Fossil diatom assemblages from June Lake sediments chiefly consist …