Late Quaternary Lacustrine History and Paleoclimatic Significance of Pluvial Lake Cochise, Southeastern Arizona

1989 ◽  
Vol 32 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Michael R. Waters
Keyword(s):  
Late Quaternary ◽  
American Southwest ◽  
Early Holocene ◽  
Central Portion ◽  
Ancient Lake ◽  
The Holocene ◽  
Middle Holocene ◽  
Ephemeral Lakes ◽  
Independent Evaluation ◽  
Paleoclimatic Significance

AbstractDuring the latest Quaternary, freshwater pluvial lakes intermittently formed in the topographically closed Willcox basin, Arizona. A lacustrine sequence of six separate high stands of Lake Cochise is documented by stratigraphic studies, 19 radiocarbon ages, and supplementary evidence. Two stands of pluvial Lake Cochise, older than 14,000 yr B.P., reached elevations above 1290 m. The prominent 1274-m shoreline of Lake Cochise, which circumscribes the basin, was largely created during a high stand between 13,750 and 13,400 yr B.P. During the Holocene, water filled the Willcox basin three times to an elevation slightly below the crest of the 1274-m shoreline. This occurred once during the early Holocene around or before 8900 yr B.P. and twice during the later part of the middle Holocene. Since the middle Holocene, only shallow ephemeral lakes have occupied the deflated central portion of ancient Lake Cochise, a depression known as the Willcox Playa. The lacustrine sequence of Lake Cochise provides an independent evaluation of late Quaternary paleoclimatic reconstructions for southern Arizona and the American Southwest.

scholarly journals New speleothem data from Molinos and Ejulve caves reveal Holocene hydrological variability in northeast Iberia

2017 ◽  
Vol 88 (2) ◽  
pp. 223-233 ◽  
Author(s):  
Ana Moreno ◽  
Carlos Pérez-Mejías ◽  
Miguel Bartolomé ◽  
Carlos Sancho ◽  
Isabel Cacho ◽  
...  
Keyword(s):  
Water Availability ◽  
Marked Change ◽  
Western Mediterranean ◽  
Early Holocene ◽  
Spring Precipitation ◽  
The Holocene ◽  
Middle Holocene ◽  
Hydrological Variability ◽  
Iberian Range ◽  
Climatic Signal

AbstractNew speleothem records from northeastern Iberian caves provide data to explore the climatic patterns during the Holocene. We present δ13C and Mg/Ca from three speleothems from two different caves located in the Iberian Range allowing replication of the climatic signal for several millennia. Through the integration of those stalagmites covering since the Holocene onset to 2 ka, the early Holocene (11.7–8.5 ka) appears as the wettest interval. A marked change towards aridity is observed during the middle Holocene (8.5–4.8 ka) and an increase of humidity afterwards (4.8–2 ka). This three-part pattern, contrasting with other Iberian sequences, seems to be associated with the different role that seasonality has played in the response of different proxies (or records) to changes in water availability. Interpreting our speleothem records as changes in winter-spring precipitation along the Holocene allows reconciling previous data on hydrological variability from the western Mediterranean borderlands.

Late Quaternary Vegetation and Early Holocene Quantitative Climate Estimates from Morwell Swamp, Latrobe Valley, South-eastern Australia

1997 ◽  
Vol 45 (3) ◽  
pp. 549 ◽  
Author(s):  
P. J. Lloyd ◽  
A. P. Kershaw
Keyword(s):  
Late Quaternary ◽  
Early Holocene ◽  
Pollen Diagram ◽  
The Holocene ◽  
Brasenia Schreberi ◽  
South Eastern ◽  
Eastern Australia ◽  
Summer Temperatures ◽  
Vegetation And Climate ◽  
South Eastern Australia

A pollen diagram from Morwell Swamp provides a record of vegetation and climate through the Holocene period while the application of a bioclimatic analysis of the aquatic species Brasenia schreberi to the occurrence of its pollen in the record allows the first quantitative reconstruction of early Holocene climate from mainland south-eastern Australia. The beginning of the Holocene, c. 10000 years before present (BP), was marked by the establishment of permanent water within the basin and an expansion of forest under conditions of increasing precipitation and probably also temperature. The early Holocene forests were dominated by Casuarinaceae, a situation typical of lowland south-eastern Australia. The presence of Brasenia schreberi Gmel., a species now restricted to lower latitudes, suggests that, by c. 9000 years BP, mean annual temperatures had risen to slighly above today’s values, while summer temperatures may have been at least 1.3˚C higher. These results are surprising considering that most previous evidence has suggested that optimal climatic conditions were achieved between about 7000 and 5000 years ago, and that radiation levels are predicted, from Milankovitch forcing, to have been lower than today at this time in the Southern Hemisphere. It is clearly necessary to be somewhat cautious about the wholescale acceptance of the quantitative values at this stage, although they are not contradicted by other palynological data. Subsequent regional increases in the wetter forest elements, Nothofagus and Pomaderris, indicate a middle Holocene peak in precipitation, although it is estimated, from a bioclimatic analysis of Nothofagus, that summer temperatures had become substantially lower than today. This lowering may have been due to a local or regional increase in cloud cover. There is evidence for minor variation in vegetation and climate within the late Holocene, which is consistent with evidence from elsewhere within the region.

Late Quaternary Inland Dunes of Southern Louisiana and Arid Climate Phases in the Gulf Coast Region

2001 ◽  
Vol 55 (2) ◽  
pp. 150-158 ◽  
Author(s):  
Ervin G. Otvos ◽  
David M. Price
Keyword(s):  
Gulf Coast ◽  
Late Quaternary ◽  
Coastal Region ◽  
Early Holocene ◽  
Arid Climate ◽  
Subtropical Climate ◽  
Mississippi Valley ◽  
Climate Conditions ◽  
Lower Mississippi Valley ◽  
Middle Holocene

AbstractThirty-five sand hills that form six scattered groups rise abruptly from the flat late Pleistocene coastal plain in southeastern Louisiana. New studies confirm their eolian origin. For the first time, several late Wisconsin to early Holocene episodes of arid climate conditions have been recognized and dated in this currently humid warm-temperate subtropical region. Periods of dune formation and reactivation (28,800 to 7900 yr B.P.) were determined by the thermoluminescence method. The onset of the current climate in this Gulf coastal region postdates early Holocene time. The textural and structural homogeneity of the ridge lithosomes, good sorting of their sand fraction, and the dominantly orange hues of the dune sediments contrast with the underlying yellowish–brown to light-brown sandy silts and the well-stratified, occasionally gravelly sands of the underlying alluvial Prairie Formation. Sharply defined, unconformable ridge bases; symmetrical, oval, occasionally parabolic mound shapes; and steep slopes confirm the dune origins. The dominant orientations of ridges and ridge chains clearly reflect paleowind directions. Age comparison with dunes of the lower Mississippi Valley, the northeastern–eastern Gulf of Mexico coast, and south Atlantic coastal areas confirms the existence of at least seasonally dry climate conditions from early Wisconsin to middle Holocene times. The onset of the modern humid-subtropical climate phase in this region thus dates back only to the middle Holocene.

Late Wisconsin Macrofossil Records of Desert Vegetation in the American Southwest

1983 ◽  
Vol 19 (2) ◽  
pp. 256-264 ◽  
Author(s):  
W. Geoffrey Spaulding
Keyword(s):  
Sonoran Desert ◽  
Mojave Desert ◽  
American Southwest ◽  
Early Holocene ◽  
Desert Vegetation ◽  
Middle Holocene ◽  
Vegetation Mosaic ◽  
Desert Scrub

AbstractUntil recently, the oldest-known packrat (Neotoma spp.) midden records of desert scrub vegetation were less than 10,500 yr old and were restricted to altitudes below 300 m in the northern Sonoran Desert. Recent discovery of macrofossil assemblages in the Mojave Desert extends the record of desert vegetation back to 14,800 yr ago and to altitudes as high as 910 m. Although xerophytic conifer woodland was widespread in current desert habitats during the Late Wisconsin and early Holocene, the development of extensive desert vegetation was not delayed until the beginning of the middle Holocene. A regional vegetation mosaic of desert scrub and woodland existed at altitudes below 1000 m in the Mojave Desert during the last part of the Late Wisconsin.

scholarly journals Late Quaternary Environments of the Teton Mountains, Wyoming: A Pollen Record from Green Lake

2018 ◽  
Vol 7 (2) ◽  
pp. 99
Author(s):  
Behnaz Balmaki ◽  
Peter Wigand
Keyword(s):  
Complex Dynamics ◽  
Forest Succession ◽  
Late Quaternary ◽  
Early Holocene ◽  
Pollen Record ◽  
The West ◽  
Middle Holocene ◽  
Mountain Glaciers ◽  
Green Lake ◽  
Plant Assemblages

Late Quaternary forest succession in Wyoming’s Rocky Mountains, occurred in random patterns, because it reflects differences between the Glacial vegetation at lower elevations on the east vs. the west of the Rockies, as well as along the mountain crest to the south. Differential melting of mountain glaciers resulted in differences in the timing of recolonization. Significant variations in the composition of plant assemblages occurred due to delays in species’ arrival, and even in the exclusion of species. Holocene climate variability, especially ongoing global warming, added to the complex dynamics of plant assemblages with warm climate species replacing early Holocene, cooler climate species. The pollen record from Green Lake (located in a glacial cirque on the west side of the Teton Mountains in Teton County, Wyoming) addresses the local vegetation response from just before the fall of Mazama ash to the end of the middle Holocene warm period. Although the earlier portion of the pollen sequence records some of the last adjustments as some plant species were still arriving after de-glaciation, by the time Mazama ash fell it was climate variation that determined most of the dynamics observed in the Green Lake record. The results reveal a sequence of wetter and drier periods based upon the presence of diagnostic tree species.  A moist late early Holocene was followed by a dry middle Holocene, which ended about 6,400 cal. B.P., and was followed between 5,000 to 2,800 cal. B.P. by a sequence of drier and moister climate episodes.

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.

Vertebrate paleontology, stratigraphy, and paleohydrology of Tule Springs Fossil Beds National Monument, Nevada (USA)

2017 ◽  
Vol 4 ◽  
pp. 55-98
Author(s):  
Kathleen Springer ◽  
Jeffrey Pigati ◽  
Eric Scott
Keyword(s):  
Las Vegas ◽  
Late Quaternary ◽  
Plant Macrofossils ◽  
Distinct Species ◽  
American Southwest ◽  
Local Fauna ◽  
Climatic Oscillations ◽  
Las Vegas Valley ◽  
National Monument ◽  
Desert Wetlands

Tule Springs Fossil Beds National Monument (TUSK) preserves 22,650 acres of the upper Las Vegas Wash in the northern Las Vegas Valley (Nevada, USA). TUSK is home to extensive and stratigraphically complex groundwater discharge (GWD) deposits, called the Las Vegas Formation, which represent springs and desert wetlands that covered much of the valley during the late Quaternary. The GWD deposits record hydrologic changes that occurred here in a dynamic and temporally congruent response to abrupt climatic oscillations over the last ~300 ka (thousands of years). The deposits also entomb the Tule Springs Local Fauna (TSLF), one of the most significant late Pleistocene (Rancholabrean) vertebrate assemblages in the American Southwest. The TSLF is both prolific and diverse, and includes a large mammal assemblage dominated by Mammuthus columbi and Camelops hesternus. Two (and possibly three) distinct species of Equus, two species of Bison, Panthera atrox, Smilodon fatalis, Canis dirus, Megalonyx jeffersonii, and Nothrotheriops shastensis are also present, and newly recognized faunal components include micromammals, amphibians, snakes, and birds. Invertebrates, plant macrofossils, and pollen also occur in the deposits and provide important and complementary paleoenvironmental information. This field compendium highlights the faunal assemblage in the classic stratigraphic sequences of the Las Vegas Formation within TUSK, emphasizes the significant hydrologic changes that occurred in the area during the recent geologic past, and examines the subsequent and repeated effect of rapid climate change on the local desert wetland ecosystem.

The sensitivity of Neotoma to climate change and biodiversity loss over the late Quaternary

2021 ◽  
pp. 1-15
Author(s):  
Catalina P. Tomé ◽  
S. Kathleen Lyons ◽  
Seth D. Newsome ◽  
Felisa A. Smith
Keyword(s):  
Body Size ◽  
Late Quaternary ◽  
Climatic Variability ◽  
Isotope Analysis ◽  
Biodiversity Loss ◽  
Bone Collagen ◽  
Cam Plants ◽  
The Holocene ◽  
Carbon And Nitrogen ◽  
Terminal Pleistocene

Abstract The late Quaternary in North America was marked by highly variable climate and considerable biodiversity loss including a megafaunal extinction event at the terminal Pleistocene. Here, we focus on changes in body size and diet in Neotoma (woodrats) in response to these ecological perturbations using the fossil record from the Edwards Plateau (Texas) across the past 20,000 years. Body mass was estimated using measurements of fossil teeth and diet was quantified using stable isotope analysis of carbon and nitrogen from fossil bone collagen. Prior to ca. 7000 cal yr BP, maximum mass was positively correlated to precipitation and negatively correlated to temperature. Independently, mass was negatively correlated to community composition, becoming more similar to modern over time. Neotoma diet in the Pleistocene was primarily sourced from C3 plants, but became progressively more reliant on C4 (and potentially CAM) plants through the Holocene. Decreasing population mass and higher C4/CAM consumption was associated with a transition from a mesic to xeric landscape. Our results suggest that Neotoma responded to climatic variability during the terminal Pleistocene through changes in body size, while changes in resource availability during the Holocene likely led to shifts in the relative abundance of different Neotoma species in the community.

Sign in / Sign up

Export Citation Format

Share Document