scholarly journals Supplemental Material: Late Quaternary geochronologic record of soil formation and erosion: Effects of climate change on Mojave Desert hillslopes (Nevada, USA)

2021 ◽  
Author(s):  
Lyman Persico ◽  
et al.
Keyword(s):  
Climate Change ◽  
Soil Profile ◽  
Mojave Desert ◽  
Late Quaternary ◽  
Soil Formation ◽  
Laser Diffraction ◽  
Environmental Information ◽  
Field Site ◽  
Field Mapping

Additional environmental information about the field site and soil profile descriptions, and details on the methods used for field mapping and OSL, XRF, and laser diffraction analyses.<br>

scholarly journals Supplemental Material: Late Quaternary geochronologic record of soil formation and erosion: Effects of climate change on Mojave Desert hillslopes (Nevada, USA)

2021 ◽  
Author(s):  
Lyman Persico ◽  
et al.
Keyword(s):  
Climate Change ◽  
Soil Profile ◽  
Mojave Desert ◽  
Late Quaternary ◽  
Soil Formation ◽  
Laser Diffraction ◽  
Environmental Information ◽  
Field Site ◽  
Field Mapping

Additional environmental information about the field site and soil profile descriptions, and details on the methods used for field mapping and OSL, XRF, and laser diffraction analyses.<br>

Desert wetlands record hydrologic variability within the Younger Dryas chronozone, Mojave Desert, USA

2018 ◽  
Vol 91 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Jeffrey S. Pigati ◽  
Kathleen B. Springer ◽  
Jeffrey S. Honke
Keyword(s):  
Climate Change ◽  
Great Basin ◽  
Mojave Desert ◽  
Late Quaternary ◽  
Younger Dryas ◽  
Human Society ◽  
Wetland Ecosystems ◽  
Hydrologic Variability ◽  
Dry Conditions ◽  
Wet And Dry Cycles

AbstractOne of the enduring questions in the field of paleohydrology is how quickly desert wetland ecosystems responded to past episodes of abrupt climate change. Recent investigations in the Las Vegas Valley of southern Nevada have revealed that wetlands expanded and contracted on millennial and sub-millennial timescales in response to changes in climate during the late Quaternary. Here, we evaluate geologic evidence from multiple localities in the Mojave Desert and southern Great Basin that suggests the response of wetland systems to climate change is even faster, occurring at centennial, and possibly decadal, timescales. Paleowetland deposits at Dove Springs Wash, Mesquite Springs, and Little Dixie Wash, California, contain evidence of multiple wet and dry cycles in the form of organic-rich black mats, representing periods of past groundwater discharge and wet conditions, interbedded with colluvial, alluvial, and aeolian sediments, each representing dry conditions. Many of these wet-dry cycles date to within the Younger Dryas (YD) chronozone (12.9–11.7 ka), marking the first timeintra-YD hydrologic variability has been documented in paleowetland deposits. Our results illustrate that desert wetland ecosystems are exceptionally sensitive to climate change and respond to climatic perturbations on timescales that are relevant to human society.

scholarly journals Late Quaternary geochronologic record of soil formation and erosion: Effects of climate change on Mojave Desert hillslopes (Nevada, USA)

Geology ◽  
2021 ◽  
Author(s):  
L.P. Persico ◽  
L.D. McFadden ◽  
J.R. McAuliffe ◽  
T.M. Rittenour ◽  
T.E. Stahlecker ◽  
...  
Keyword(s):  
Climate Change ◽  
Mojave Desert ◽  
Vegetation Change ◽  
Climatic Factors ◽  
Late Quaternary ◽  
Perennial Grass ◽  
Soil Development ◽  
Grass Cover ◽  
The Holocene ◽  
Middle Holocene

Climate change is an often-cited control on geomorphic processes in the arid southwestern United States, but links to direct climatic factors and vegetation change remain under debate. Hillslopes at a site in the eastern Mojave Desert in southern Nevada are mantled by 0–1.5 m of colluvial deposits. Accumulation of weathered bedrock combined with eolian inputs of fine sand and silt led to the formation of well-developed soil profiles. Surface sediments from both sources were incorporated into colluvium, allowing both processes to be dated with optically stimulated luminescence (OSL). OSL ages indicate a period of increased colluviation in the Late Pleistocene facilitated by enhanced bedrock weathering and dust deposition. Hillslope aspect strongly controls predominant soil environments and associated vegetation. Well-developed soils with dense grass cover extensively mantle the mesic north-aspect hillslopes, while more xeric south-aspect hillslopes are dominated by thin colluvium with minimal soil development, extensive bedrock exposure, and desertscrub vegetation. Remnants of older colluvium with moderately developed soils on south aspects, however, indicate they were once more extensively mantled by thicker colluvial deposits. The transition to drier conditions in the Holocene diminished vegetation cover on more xeric south aspects, triggering widespread erosion, whereas the more mesic north aspects retained denser grass cover that minimized erosion. The transition to drier conditions in the Holocene altered the vegetation; however, persistent perennial grass cover minimized erosion into the middle Holocene. Increasing aridity during the middle Holocene significantly reduced grass cover on more xeric south aspects, triggering erosion and alluvial deposition. OSL dates of dust incorporated into terrace sediments indicate late Middle Holocene aggradation and soil development in the Late Holocene. In contrast, maintenance of substantial perennial grass cover on mesic north aspects minimized erosion from those hillslopes throughout the Holocene.

Quaternary Mammal Communities: Relevance of the Individualistic Response and Non-Analogue Faunas

2005 ◽  
Vol 11 ◽  
pp. 141-158 ◽  
Author(s):  
Russell W. Graham
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Natural Experiment ◽  
Late Quaternary ◽  
Global Climate ◽  
Land Use Management ◽  
Change Analysis ◽  
Climate Fluctuations ◽  
Core Species ◽  
Mammal Communities

Frequent and repeated climate fluctuations of the late Quaternary serve as a “natural experiment” for the response of species to environmental change. Analysis of the FAUNMAP database documents individualistic shifts in the geographic distributions for late Quaternary mammals. However, because the individualistic response is not necessarily random and because many species share similar niche parameters, it is possible that some species appear to form coherent groups of core species. In reality their dispersals are individualistic with regard to rate and timing. The individualistic response of mammals, as well as that of other organisms, has created late Quaternary communities without modern analogues. This concept has profound implications for the design of biological reserves and for land use management with respect to future global climate change. However, the relevance of non-analogue mammal communities has been challenged by Alroy (1999), who claims that non-analogue associations were not common in the Quaternary and that they appeared to occur in both the Pleistocene and Holocene. Reexamination of his analysis shows that he employed a different definition for non-analogue faunas and that his methods of analyses created artificially low counts of non-analogue communities and consequently an underestimate of their importance.

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