Physical Sciences and Mathematics | Open Access Articles

Climate Response In Near-Treeline Bristlecone Pine, Matthew W. Salzer, Evan R. Larson, Andrew Godard Bunn, Malcolm Kenneth Hughes

Environmental Sciences Faculty and Staff Publications

In the White Mountains of California, eight bristlecone pine (Pinus longaeva) tree-ring width chronologies were developed from trees at upper treeline and just below upper treeline along North- and South-facing elevational transects from treeline to ~90 m below. There is evidence for a climate-response threshold between approximately 60–80 vertical m below treeline, above which trees have shown a positive growth-response to temperature and below which they do not. Chronologies from 80 m or more below treeline show a change in climate response and do not correlate strongly with temperature-sensitive chronologies developed from trees growing at upper treeline. Rather, they more …

Go to article

Aptian To Santonian Foraminiferal Biostratigraphy And Paleoenvironmental Change In The Sverdrup Basin As Revealed At Glacier Fiord, Axel Heiberg Island, Canadian Arctic Archipelago, Claudia J. Schröder-Adams, Jens O. Herrle, Ashton F. Embry, James W. Haggart, Jennifer M. Galloway, Adam T. Pugh, David M. Harwood

ANDRILL Research and Publications

Exceptional exposures of a High Arctic Cretaceous sedimentary record were studied at Glacier Fiord, Axel Heiberg Island. The succession reveals a complex Aptian to Santonian paleoenvironmental history of the Sverdrup Basin that documents several global events. Foraminiferal faunas in combination with rare macrofossil occurrences permit the distinction of nine zones that facilitate biostratigraphic correlations to other High Arctic locales, the Beaufort Mackenzie Basin and the Western Interior Sea. The depositional environment as exposed in the Christopher, Hassel, Bastion Ridge and Kanguk formations changed frequently from a shelf to a shoreface setting. Most sequence boundaries appear to be conformable where shoaling …

Go to article

Wetlands On The Thousand Lake Mountain Mega-Landslide As Paleoclimate Proxies, Ryan Andros Shurtliff

Theses and Dissertations

The Windy Ridge mega-landslide in Wayne and Sevier Counties originated in Lates tPleistocene time as established by 14C ages on basal organic-rich clay and peat sediment from bogs that developed on the slide. The contact depth between bog and landslide was estimated using high-resolution seismic reflection to find the thickest sediment. Four bogs were cored at their depocenters, and organic material at the slide contact was used for age determinations. The oldest bog sediments ages are 10,600 ± 46, 10,556 ± 34, 12,511 ± 134, and 12,886 ± 91 calibrated years BP. Ages represent two sliding events. First, at the …

Go to article

Stratigraphic Framework And Quaternary Paleolimnology Of The Lake Turkana Rift, Kenya, Amy Morrissey

Dissertations - ALL

Lake sediments are some of the best archives of continental climate change, particularly in the tropics. This study is focused on three ~10m sediment cores and high-resolution seismic reflection data from Lake Turkana in northern Kenya. Lake Turkana is the world's largest desert lake and the largest lake in the Eastern Branch of the East African Rift System. It is situated at ~2 °N at 360 m elevation and is ~250 km long and ~30 km wide with a mean depth of 35 m. The lake surface receives less than 200 mm yr-1 of rainfall during the twice-annual passing of …

Go to article

Structure, Paleolimnology And Basin History Of The East Kivu Graben, Lake Kivu, Rwanda From Offshore Seismic Reflection Data, Douglas Alan Wood

Theses - ALL

Lake Kivu, located at the topographic high point of the western branch of Africa's Great Rift Valley, is regularly subjected to large-magnitude seismic events, violent volcanic discharges, and possible limnic eruptions which pose substantial geohazards to the ~two million Congolese and Rwandan people living around its basin. Although most of the western branch of Africa's Great Rift Valley is amagmatic, Lake Kivu is bordered to the north and south by two volcanic provinces. Subaqueous springs, charged by the active Virunga Magmatic Complex at the north end of the lake, currently inject gas into the deep- hypolimnion, where it remains in …

Go to article

Loess Records, Daniel R. Muhs, Stephen R. Cattle, Onn Crouvi, Denis-Didier Rousseau, Jimin Sun, Marcelo A. Zárate

United States Geological Survey: Staff Publications

Loess is aeolian sediment, dominated by silt-sized particles, that is identifiable in the field as a distinct sedimentary body. It covers a significant portion of the land surface of the Earth and as such constitutes one of the most important archives of long-term dust deposition. Large tracts of loess cover Europe, Asia, South America, and North America, and smaller loess bodies are found covering parts of Africa, the Middle East, New Zealand, and Australia. Loess thickness, particle size, and carbonate content decrease downwind from sources, trends that are powerful tools for reconstructing paleowinds. Many loess sections consist of relatively thick …

Go to article

Radiocarbon Dating Loess Deposits In The Mississippi Valley Using Terrestrial Gastropod Shells (Polygyridae, Helicinidae, And Discidae), Jeffrey S. Pigati, John Mcgeehin, Daniel R. Muhs, David A. Grimley, Jeffrey C. Nekola

United States Geological Survey: Staff Publications

Small terrestrial gastropod shells (mainly Succineidae) have been used successfully to date late Quaternary loess deposits in Alaska and the Great Plains. However, Succineidae shells are less common in loess deposits in the Mississippi Valley compared to those of the Polygyridae, Helicinidae, and Discidae families. In this study, we conducted several tests to determine whether shells of these gastropods could provide reliable ages for loess deposits in the Mississippi Valley. Our results show that most of the taxa that we investigated incorporate small amounts (1–5%) of old carbon from limestone in their shells, meaning that they should yield ages that …

Go to article

Geologic Setting And Stratigraphy Of The Ziegler Reservoir Fossil Site, Snowmass Village, Colorado, Jeffrey S. Pigati, Ian M. Miller, Kirk R. Johnson, Jeffrey S. Honke, Paul E. Carrara, Daniel R. Muhs, Gary Skipp, Bruce Bryant

United States Geological Survey: Staff Publications

The geologic setting of the Ziegler Reservoir fossil site is somewhat unusual—the sediments containing the Pleistocene fossils were deposited in a lake on top of a ridge. The lake basin was formed near Snowmass Village, Colorado (USA) when a glacier flowing down Snowmass Creek Valley became thick enough to overtop a low point in the eastern valley wall and entered the head of Brush Creek Valley. When the glacier retreated at about 155–130 ka, near the end of Marine Oxygen Isotope Stage 6, the Brush Creek Valley lobe left behind a moraine that impounded a small alpine lake. The lake …

Go to article

Summary Of The Snowmastodon Project Special Volume: A High-Elevation, Multi-Proxy Biotic And Environmental Record Of Mis 6–4 From The Ziegler Reservoir Fossil Site, Snowmass Village, Colorado, Usa, Ian M. Miller, Jeffrey S. Pigati, R. Scott Anderson, Kirk R. Johnson, Shannon A. Mahan, Thomas A. Ager, Richard G. Baker, Maarten Blaauw, Jordon Bright, Peter M. Brown, Bruce Bryant, Zachary T. Calamari, Paul E. Carrara, Michael D. Cherney, John R. Demboski, Scott A. Elias, Daniel C. Fisher, Harrison J. Gray, Danielle R. Haskett, Jeffrey S. Honke, Stephen T. Jackson, Gonzalo Jiménez- Moreno, Douglas Kline, Eric M. Leonard, Nathaniel A. Lifton, Carol Lucking, H. Gregory Mcdonald, Dane M. Miller, Daniel R. Muhs, Stephen E. Nash, Cody Newton, James B. Paces, Lesley Petrie, Mitchell A. Plummer, David F. Porinchu, Adam N. Rountrey, Eric Scott, Joseph J.W. Sertich, Saxon E. Sharpe, Gary L. Skipp, Laura E. Strickland, Richard K. Stucky, Robert S. Thompson, Jim Wilson

United States Geological Survey: Staff Publications

In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones …

Go to article

Physical Sciences and Mathematics Commons^™

Full-Text Articles in Physical Sciences and Mathematics

Climate Response In Near-Treeline Bristlecone Pine, Matthew W. Salzer, Evan R. Larson, Andrew Godard Bunn, Malcolm Kenneth Hughes

Environmental Sciences Faculty and Staff Publications

ANDRILL Research and Publications

Wetlands On The Thousand Lake Mountain Mega-Landslide As Paleoclimate Proxies, Ryan Andros Shurtliff

Theses and Dissertations

Stratigraphic Framework And Quaternary Paleolimnology Of The Lake Turkana Rift, Kenya, Amy Morrissey

Dissertations - ALL

Structure, Paleolimnology And Basin History Of The East Kivu Graben, Lake Kivu, Rwanda From Offshore Seismic Reflection Data, Douglas Alan Wood

Theses - ALL

Loess Records, Daniel R. Muhs, Stephen R. Cattle, Onn Crouvi, Denis-Didier Rousseau, Jimin Sun, Marcelo A. Zárate

United States Geological Survey: Staff Publications

Radiocarbon Dating Loess Deposits In The Mississippi Valley Using Terrestrial Gastropod Shells (Polygyridae, Helicinidae, And Discidae), Jeffrey S. Pigati, John Mcgeehin, Daniel R. Muhs, David A. Grimley, Jeffrey C. Nekola

United States Geological Survey: Staff Publications

Geologic Setting And Stratigraphy Of The Ziegler Reservoir Fossil Site, Snowmass Village, Colorado, Jeffrey S. Pigati, Ian M. Miller, Kirk R. Johnson, Jeffrey S. Honke, Paul E. Carrara, Daniel R. Muhs, Gary Skipp, Bruce Bryant

United States Geological Survey: Staff Publications

United States Geological Survey: Staff Publications