On the Physical Geography of the Colorado Basin and the Great Basin Region of North America

1868 ◽  
Vol 13 (3) ◽  
pp. 140
Author(s):  
W. A. Bell
Keyword(s):  
North America ◽  
Great Basin ◽  
Physical Geography ◽  
Basin Region ◽  
Colorado Basin

scholarly journals Phylogeography of the pallid kangaroo mouse,Microdipodops pallidus: a sand-obligate endemic of the Great Basin, western North America

2008 ◽  
Vol 35 (11) ◽  
pp. 2102-2118 ◽  
Author(s):  
John C. Hafner ◽  
Nathan S. Upham ◽  
Emily Reddington ◽  
Candice W. Torres
Keyword(s):  
North America ◽  
Great Basin ◽  
Western North America

The first record of Cancelloceras (Early Pennsylvanian Ammonoidea) from southern Nevada: Implications for timing of regional mid-Carboniferous sea-level fluctuations

1997 ◽  
Vol 71 (1) ◽  
pp. 158-162 ◽  
Author(s):  
Alan L. Titus
Keyword(s):  
Great Basin ◽  
Las Vegas ◽  
First Record ◽  
Field Trip ◽  
Geological Society ◽  
Clark County ◽  
Sea Level Fluctuations ◽  
Southern Nevada ◽  
Carbonate Deposition ◽  
Basin Region

In 1988, the presence of an Early Pennsylvanian ammonoid assemblage within the basal meter of the Callville Formation (Pennsylvanian-Permian), eastern Clark County, Nevada, was brought to the attention of the author by Stephen M. Rowland, University of Nevada-Las Vegas. The ammonoids occur in the Frenchman Mountain section described by Rowland (1987) for the Geological Society of America's Decade of North American Geology (DNAG) field trip compendium. The mid-Carboniferous section at this locality (Figure 1) was discussed in two other field trip guides as well (Langenheim and Webster, 1979; Webster et al., 1984). No ammonoids have been reported previously from this locality. Although this is the first record of Cancelloceras from the Great Basin region, the assemblage also provides a narrowly constrained age for the basal part of the Callville Formation at Frenchman Mountain, which in turn, dates the initiation of carbonate deposition following a major mid-Carboniferous hiatus in the southern Great Basin.

Geoarchaeological and Paleohydrological Evidence for a Clovis-Age Drought in North America and Its Bearing on Extinction

1991 ◽  
Vol 35 (3-Part1) ◽  
pp. 438-450 ◽  
Author(s):  
C. Vance Haynes
Keyword(s):  
North America ◽  
Great Basin ◽  
Water Table ◽  
Marked Decrease ◽  
Northern Europe ◽  
Dry Period ◽  
Human Predation ◽  
Water Table Rise ◽  
Algal Mat ◽  
Game Animals

AbstractAt the Murray Springs Clovis site in southeastern Arizona, stratigraphic and geomorphic evidence indicates that an abnormally low water table 10,900 yr B.P. was followed soon thereafter by a water-table rise accompanied by the deposition of an algal mat (the “black mat”) that buried mammoth tracks, Clovis artifacts, and a well. This water-table fluctuation correlates with pluvial lake fluctuations in the Great Basin during and immediately following Clovis occupation of that region. Many elements of Pleistocene megafauna in North America became extinct during the dry period. Oxygen isotope records show a marked decrease in δ18O correlated with the Younger Dryas cold-dry event of northern Europe which ended 10,750 yr B.P., essentially the same time as the water table began to rise in southeastern Arizona. Clovis hunters may have found large game animals easier prey when concentrated at water holes and under stress. If so, both climate and human predation contributed to Pleistocene extinction in America.

North American rainfall patterns during past warm states: A proxy network-model comparison for the Last Interglacial and the mid-Holocene

2021 ◽  
Author(s):  
Cameron de Wet ◽  
Jessica Oster ◽  
Daniel Ibarra ◽  
Bryce Belanger
Keyword(s):  
North America ◽  
Pacific Northwest ◽  
Great Basin ◽  
North American ◽  
Last Interglacial ◽  
The North ◽  
Driving Mechanisms ◽  
Statistical Measures ◽  
Spatial Coverage ◽  
Rainfall Patterns

<p>The Last Interglacial (LIG) period (~129,000–116,000 years BP) and the mid-Holocene (MH) (~6,000 years BP) are the two most recent intervals with temperatures comparable to low emissions scenarios for the end of the 21<sup>st</sup> century. During the LIG and the MH differences in the seasonal and latitudinal distribution of insolation led to enhanced northern hemisphere high-latitude warmth relative to the pre-industrial, despite similar greenhouse gas concentrations, marking these intervals as potentially useful analogs for future change in regions like North America. Further, the inclusion of both LIG (127 ka) and MH (6 ka) experiments in the CMIP6-PMIP4 effort provides an opportunity to better understand the regional hydroclimate responses to radiative forcing during these two intervals. The dense coverage of paleoclimate proxy records for North America during the MH (N=260 sites) reveals a pattern of relative aridity in the Pacific Northwest and Western Canada and wetness in the southern Great Basin and Mexico. However, the seasonality and driving mechanisms of rainfall patterns across the continent remain poorly understood. Our understanding of terrestrial hydroclimate in North America during the LIG is more limited (N=39 sites), largely because the LIG is beyond the range of radiocarbon dating.</p><p>Here we present spatial comparisons between output from 14 PMIP4 global circulation models and LIG and MH networks of moisture-sensitive proxies compiled for the North American continent. We utilize two statistical measures of agreement – weighted Cohen’s Kappa and Gwet’s AC2 – to assess the degree of categorical agreement between moisture patterns produced by the models and the proxy networks for each time-slice. PMIP4 models produce variable precipitation anomalies relative to the pre-industrial for both the LIG and MH experiments, often disagreeing on both the sign and magnitude of precipitation changes across much of North America. The models showing the best agreement with the proxy network are similar but not identical for the two measures, with Gwet’s AC2 values tending to be larger than Cohen’s Kappa values for all models. This pattern is enhanced for the much larger MH proxy network and is likely related to the fact that Gwet’s AC2 is a more predictable statistic in the presence of high agreement. Overall agreement is lower for the mid-Holocene than for the LIG, reflecting smaller MH rainfall anomalies in the models. The models with the highest agreement scores during the LIG produce aridity in the Rocky Mountains and Pacific Northwest and wetness in Alaska, the Yukon, the Great Basin, and parts of the Mid-West and Eastern US, although spatial coverage of the proxies in these latter two regions is poor. The models with the highest agreement score for the mid-Holocene tend to produce aridity across Canada and the northern US with dry conditions extending down the US Pacific coast and increased wetness in the American Southeast and across the North American Monsoon region. Our analyses help elucidate the driving mechanisms of rainfall patterns during past warm states and can inform which models may be the most useful for predictions of near-future hydroclimate change across North America.</p>

scholarly journals The Role of Basketry in Early Holocene Small Seed Exploitation: Implications of a Ca. 9,000 Year-Old Basket from Cowboy Cave, Utah

2008 ◽  
Vol 73 (1) ◽  
pp. 83-102 ◽  
Author(s):  
Phil R. Geib ◽  
Edward A. Jolie
Keyword(s):  
North America ◽  
Great Basin ◽  
Processing Technique ◽  
Early Holocene ◽  
Western North America ◽  
Seed Processing ◽  
Small Seed ◽  
Food Exploitation ◽  
The Continuum

Despite ranking at the low end of the continuum in net caloric benefit relative to other foods, small seeds assumed great dietary importance in many parts of the world, including western North America. In a series of publications, Adovasio (1970a, 1974, 1980, 1986) argued that coiled basketry technology was invented in the eastern Great Basin during the early Holocene as a specialized food-processing technique. Coiled baskets are indeed useful for collecting and processing seeds, but it does not necessarily follow that they were originally designed for this purpose. A whole basket recently discovered at Cowboy Cave in southeastern Utah returned an AMS radiocarbon assay of 7960 ± 50 B.P., making it currently the earliest directly dated coiled basket from the Americas. This basket is not a parching tray and likely had nothing to do with harvesting seeds. We discuss the implications of this find with regard to tracking the temporal spread of coiled basketry technology in western North America and the role of coiled and twined forms in the initiation of small seed exploitation. Coiled and twined baskets for small seed processing may result from reconfiguration of existing technologies to create novel forms suited to a new food exploitation strategy.

Impact of Alien Plants on Grant Basin Rangelands

1996 ◽  
Vol 10 (2) ◽  
pp. 384-391 ◽  
Author(s):  
James A. Young ◽  
William S. Longland
Keyword(s):  
North America ◽  
Great Basin ◽  
Alien Plants ◽  
Western North America ◽  
Biological Functions ◽  
Annual Species ◽  
Weed Species ◽  
Model Ecosystem ◽  
Alien Weed ◽  
The Impact

Our purpose is to discuss the impact of alien plants on rangeland ecosystems of the Great Basin in terms of their effects on biological functions. The sagebrush/bunchgrass ranges of western North America are used as a model ecosystem for the impact of alien plants. Alien weed species have been introduced in successive waves, with the success of each new introduction dependent on how well adapted to the environment and how competitive the new weed is with those previously introduced. Annual species have been successful across extensive areas of Great Basin rangelands. Biennial and short- and long-lived perennial introductions have been restricted to much more specific habitats. Alien plants impact rangelands through stand renewal and successional processes. Alien weeds can cause such processes to be accelerated and/or truncated depending on the species and range site.

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