A quantitative midge-based reconstruction of mean July air temperature from a high-elevation site in central Colorado, USA, for MIS 6 and 5

2014 ◽  
Vol 82 (3) ◽  
pp. 580-591 ◽  
Author(s):  
Danielle R. Haskett ◽  
David F. Porinchu
Keyword(s):  
Sierra Nevada ◽  
Air Temperature ◽  
High Elevation ◽  
Oxygen Isotope Stage ◽  
Subfossil Chironomids ◽  
Air Temperatures ◽  
Fossil Site ◽  
Colorado Rockies ◽  
Mis 5E ◽  
Mis 5

AbstractSediments recovered from the Ziegler Reservoir fossil site (ZRFS) in Snowmass Village, Colorado (USA) were analyzed for subfossil chironomids (or midges). The midge stratigraphy spans ~140–77 ka, which includes the end of Marine Oxygen Isotope Stage (MIS) 6 and all of MIS 5. Notable shifts in midge assemblages occurred during two discrete intervals: the transition from MIS 6 to MIS 5e and midway through MIS 5a. A regional calibration set, incorporating lakes from the Colorado Rockies, Sierra Nevada, and Uinta Mountains, was used to develop a midge-based mean July air temperature (MJAT) inference model (r2jack = 0.61, RMSEP = 0.97°C). Model results indicate that the transition from MIS 6 to MIS 5e at the ZRFS was characterized by an increase in MJAT from ~9.0 to 10.5°C. The results also indicate that temperatures gradually increased through MIS 5 before reaching a maximum of 13.3°C during MIS 5a. This study represents the first set of quantitative, midge-based MJAT estimates in the continental U.S. that spans the entirety of MIS 5. Overall, our results suggest that conditions in the Colorado Rockies throughout MIS 5 were cooler than today, as the upper limit of the reconstructed temperatures is ~2°C below modern July air temperatures.

Taxonomic overview and tusk growth analyses of Ziegler Reservoir proboscideans

2014 ◽  
Vol 82 (3) ◽  
pp. 518-532 ◽  
Author(s):  
Daniel C. Fisher ◽  
Michael D. Cherney ◽  
Cody Newton ◽  
Adam N. Rountrey ◽  
Zachary T. Calamari ◽  
...  
Keyword(s):  
High Elevation ◽  
Environmental Pressures ◽  
Terminal Pleistocene ◽  
Fossil Site ◽  
Males And Females ◽  
Low Levels ◽  
Colorado Rockies ◽  
Mammut Americanum ◽  
Source Of Information ◽  
Mis 5

AbstractAt an altitude of 2705 m in the Colorado Rockies (USA), the Ziegler Reservoir fossil site gives a rare look at a high-elevation ecosystem from the late Pleistocene (especially MIS 5) of North America. Remains of more than four mammoths and about 35 mastodons dominate the macrofossil assemblage. Mammoth remains are attributed to Mammuthus columbi, and mastodon remains are referred to the well-known, continent-wide Mammut americanum. Mastodon remains occur within and between several lake-margin slump deposits. Their deposition must therefore have occurred as events that were to some degree separate in time. We treat the mastodon assemblage in each stratigraphic unit as a source of information on environmental conditions during the lives of these individuals. Mastodon mandibular tusks are abundant at the site and represent both males and females, from calves to full-grown adults. This study presents the first attempt to use microCT, thin-section, and isotope records from mandibular tusks to reconstruct features of life-history. We recognize an up-section trend in δ18O profiles toward higher values, suggestive of warmer temperatures. Throughout this sequence, mastodon growth histories show low mean sensitivities suggestive of low levels of environmental stress. This work helps frame expectations for assessing environmental pressures on terminal Pleistocene populations.

scholarly journals 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

2014 ◽  
Vol 82 (3) ◽  
pp. 618-634 ◽  
Author(s):  
Ian M. Miller ◽  
Jeffrey S. Pigati ◽  
R. Scott Anderson ◽  
Kirk R. Johnson ◽  
Shannon A. Mahan ◽  
...  
Keyword(s):  
Climate Change ◽  
Black Bear ◽  
Plant Macrofossils ◽  
High Elevation ◽  
Pollen Record ◽  
Oxygen Isotope Stage ◽  
Stratigraphic Framework ◽  
Fossil Site ◽  
Nearly Continuous ◽  
Mis 5

AbstractIn 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 of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.

A high-elevation MIS 5 hydrologic record using mollusks and ostracodes from Snowmass Village, Colorado, USA

2014 ◽  
Vol 82 (3) ◽  
pp. 604-617 ◽  
Author(s):  
Saxon E. Sharpe ◽  
Jordon Bright
Keyword(s):  
Stable Isotopes ◽  
Water Temperature ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
High Elevation ◽  
Total Dissolved Solids ◽  
Water Based ◽  
Fossil Site ◽  
Mis 5E ◽  
Mis 5

AbstractSediments containing terrestrial and aquatic mollusks and ostracodes from the Ziegler Reservoir fossil site (2705 m elevation) near Snowmass Village, Colorado, span ~130–87 ka (MIS 5e through 5b). The southeastern area of the site where taxa were recovered was a relatively fresh, shallow, well-vegetated wetland during MIS 5e through 5c time, approximately 2 m deep, with a total dissolved solids value of ~200–1000 mg L− 1. The wetland was seasonally or annually variable and groundwater discharged along the margins of the bounding moraine. Groundwater likely contributed solutes to the system and may have contributed 18O-enriched water. Based on stable isotopes from ostracode calcite (δ18OOST and δ13COST), seasonal evaporation occurred and the dissolved inorganic carbon pool was unexpectedly enriched in 13C. The mollusk and ostracode faunas changed little across the MIS 5e/5d/5c boundaries, whereas a distinct change in the ostracode fauna occurred between the deposition of Unit 11 and Unit 13, which corresponds in time to the MIS 5c/5b boundary, indicating some combination of increased surface and/or groundwater flow, a decrease in water temperature, and a freshening and a possible deepening of the wetland.

High-elevation late Pleistocene (MIS 6–5) vertebrate faunas from the Ziegler Reservoir fossil site, Snowmass Village, Colorado

2014 ◽  
Vol 82 (3) ◽  
pp. 504-517 ◽  
Author(s):  
Joseph J.W. Sertich ◽  
Richard K. Stucky ◽  
H. Gregory McDonald ◽  
Cody Newton ◽  
Daniel C. Fisher ◽  
...  
Keyword(s):  
High Elevation ◽  
Ambystoma Tigrinum ◽  
Tiger Salamander ◽  
Oxygen Isotope Stage ◽  
Faunal Assemblages ◽  
Fossil Site ◽  
Lake Center ◽  
Mammut Americanum ◽  
Mis 5 ◽  
Lake Margin

AbstractThe vertebrate record at the Ziegler Reservoir fossil site (ZRFS) near Snowmass Village, Colorado ranges from ~140 to 77 ka, spanning all of Marine Oxygen Isotope Stage (MIS) 5. The site contains at least 52 taxa of macro- and microvertebrates, including one fish, three amphibian, four reptile, ten bird, and 34 mammal taxa. The most common vertebrate is Ambystoma tigrinum (tiger salamander), which is represented by >22,000 elements representing the entire life cycle. The mastodon, Mammut americanum, is the most common mammal, and is documented by >1800 skeletal elements making the ZRFS one of the largest accumulations of proboscidean remains in North America. Faunas at the ZRFS can be divided into two groups, a lake-margin group dating to ~140–100 ka that is dominated by woodland taxa, and a lake-center group dating to ~87–77 ka characterized by taxa favoring more open conditions. The change in faunal assemblages occurred between MIS 5c and 5a (vertebrates were absent from MIS 5b deposits), which were times of significant environmental change at the ZRFS. Furthermore, the ZRFS provides a well-dated occurrence of the extinct Bison latifrons, which has implications for the timing of the Rancholabrean Mammal Age in the region.

A geochronologic framework for the Ziegler Reservoir fossil site, Snowmass Village, Colorado

2014 ◽  
Vol 82 (3) ◽  
pp. 490-503 ◽  
Author(s):  
Shannon A. Mahan ◽  
Harrison J. Gray ◽  
Jeffrey S. Pigati ◽  
Jim Wilson ◽  
Nathaniel A. Lifton ◽  
...  
Keyword(s):  
Bone Collagen ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Oxygen Isotope Stage ◽  
Fine Grained ◽  
Last Interglacial Period ◽  
Fossil Site ◽  
Shell Carbonate ◽  
Mis 5

AbstractThe Ziegler Reservoir fossil site near Snowmass Village, Colorado (USA), provides a unique opportunity to reconstruct high-altitude paleoenvironmental conditions in the Rocky Mountains during the Last Interglacial Period. We used four different techniques to establish a chronological framework for the site. Radiocarbon dating of lake organics, bone collagen, and shell carbonate, and in situ cosmogenic 10Be and 26Al ages on a boulder on the crest of a moraine that impounded the lake suggest that the ages of the sediments that hosted the fossils are between ~140 ka and >45 ka. Uranium-series ages of vertebrate remains generally fall within these bounds, but extremely low uranium concentrations and evidence of open-system behavior limit their utility. Optically stimulated luminescence (OSL) ages (n = 18) obtained from fine-grained quartz maintain stratigraphic order, were replicable, and provide reliable ages for the lake sediments. Analysis of the equivalent dose (DE) dispersion of the OSL samples showed that the sediments were fully bleached prior to deposition and low scatter suggests that eolian processes were likely the dominant transport mechanism for fine-grained sediments into the lake. The resulting ages show that the fossil-bearing sediments span the latest part of Marine Oxygen Isotope Stage (MIS) 6, all of MIS 5 and MIS 4, and the earliest part of MIS 3.

A loess–paleosol record of climate and glacial history over the past two glacial–interglacial cycles (~ 150 ka), southern Jackson Hole, Wyoming

2011 ◽  
Vol 76 (1) ◽  
pp. 119-141 ◽  
Author(s):  
Kenneth L. Pierce ◽  
Daniel R. Muhs ◽  
Maynard A. Fosberg ◽  
Shannon A. Mahan ◽  
Joseph G. Rosenbaum ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Soil Development ◽  
Oxygen Isotope Stage ◽  
Climatic Oscillations ◽  
Jackson Hole ◽  
Glacial Flour ◽  
Loess Deposition ◽  
Mineral Magnetic ◽  
Mis 5E ◽  
Exposure Ages

AbstractLoess accumulated on a Bull Lake outwash terrace of Marine Oxygen Isotope Stage 6 (MIS 6) age in southern Jackson Hole, Wyoming. The 9 m section displays eight intervals of loess deposition (Loess 1 to Loess 8, oldest), each followed by soil development. Our age-depth model is constrained by thermoluminescence, meteoric 10Be accumulation in soils, and cosmogenic 10Be surface exposure ages. We use particle size, geochemical, mineral-magnetic, and clay mineralogical data to interpret loess sources and pedogenesis. Deposition of MIS 6 loess was followed by a tripartite soil/thin loess complex (Soils 8, 7, and 6) apparently reflecting the large climatic oscillations of MIS 5. Soil 8 (MIS 5e) shows the strongest development. Loess 5 accumulated during a glacial interval (~ 76–69 ka; MIS 4) followed by soil development under conditions wetter and probably colder than present. Deposition of thick Loess 3 (~ 43–51 ka, MIS 3) was followed by soil development comparable with that observed in Soil 1. Loess 1 (MIS 2) accumulated during the Pinedale glaciation and was followed by development of Soil 1 under a semiarid climate. This record of alternating loess deposition and soil development is compatible with the history of Yellowstone vegetation and the glacial flour record from the Sierra Nevada.

Introduction to the Snowmastodon Project Special Volume The Snowmastodon Project

2014 ◽  
Vol 82 (3) ◽  
pp. 473-476 ◽  
Author(s):  
Kirk R. Johnson ◽  
Ian M. Miller ◽  
Jeffrey S. Pigati ◽  
Keyword(s):  
High Elevation ◽  
Interglacial Period ◽  
Alpine Ecosystems ◽  
Special Volume ◽  
Last Interglacial ◽  
Oxygen Isotope Stage ◽  
Last Interglacial Period ◽  
Mis 5 ◽  
Insight Into

Studies of terrestrial biotic and environmental dynamics of Marine Oxygen Isotope Stage (MIS) 5, also called the Last Interglacial Period, provide insight into the effects of long-term climate change on Pleistocene ecosystems. In North America, however, there are relatively few fossil sites that definitively date to MIS 5. Even fewer contain multiple ecosystem components (vertebrates, invertebrates, plants) that have been studied in detail, and none are located at high elevation. Thus, our view of North American ecosystems during MIS 5 is, at best, an incomplete composite view, and alpine ecosystems are entirely undocumented.

High-elevation paleoenvironmental change during MIS 6–4 in the central Rockies of Colorado as determined from pollen analysis

2014 ◽  
Vol 82 (3) ◽  
pp. 542-552 ◽  
Author(s):  
R. Scott Anderson ◽  
Gonzalo Jiménez-Moreno ◽  
Thomas Ager ◽  
David F. Porinchu
Keyword(s):  
Oxygen Isotope ◽  
Rocky Mountain ◽  
High Elevation ◽  
Alpine Tundra ◽  
Pollen Record ◽  
Climatic Trends ◽  
Arboreal Pollen ◽  
Fossil Site ◽  
High Elevations ◽  
Mis 5E

AbstractPaleoecological studies from Rocky Mountain (USA) high elevations encompassing the previous interglacial (MIS 5e) are rare. The ~10-m composite profile from the Ziegler Reservoir fossil site (2705 m asl) of central Colorado allows us to determine paleoenvironments from Marine Oxygen Isotope Stages (MIS) 6– 4 using pollen zones that are approximately equivalent to marine oxygen isotope stages. During Pollen Zone (PZ) 6 time, pollen assemblages dominated by Artemisia (sagebrush) suggest that alpine tundra or steppe occurred nearby. The transition to PZ 5e was characterized by a rapid increase in tree pollen, initially Picea (spruce) and Pinus (pine) but also Quercus (oak) and Pseudotsuga menziesii (Douglas-fir). Non-arboreal pollen (NAP) types increased during PZ 5d, while Abies (fir) and Juniperus (juniper) increased during PZ 5c. Pollen evidence suggests that temperatures during PZ 5b were as cold as during PZ 6, with the site again surrounded by alpine tundra. Picea dominated during PZ 5a before the onset of cooler conditions during PZ 4. The MIS 6–MIS 5e transition here was similar to the MIS 2–MIS 1 transition at other Rocky Mountain sites. However, the Ziegler Reservoir pollen record contains evidence suggesting unexpected climatic trends at this site, including a warmer-than-expected MIS 5d and cooler-than-expected MIS 5b.

Air temperature variability in high-elevation glacierized regions: observations from six catchments on the Tibetan Plateau

2021 ◽  
Keyword(s):  
Tibetan Plateau ◽  
Air Temperature ◽  
High Elevation ◽  
Temperature Variability ◽  
The Tibetan Plateau ◽  
Katabatic Winds ◽  
Near Surface ◽  
Southeastern Tibetan Plateau ◽  
Air Temperatures ◽  
Cooling Effects

Abstract Near-surface air temperature variability and the reliability of temperature extrapolation within glacierized regions are important issues for hydrological and glaciological studies that remain elusive because of the scarcity of high-elevation observations. Based on air temperature data in 2019 collected from 12 automatic weather stations, 43 temperature loggers and 6 national meteorological stations in six different catchments, this study presents air temperature variability in different glacierized/nonglacierized regions and assesses the robustness of different temperature extrapolations to reduce errors in melt estimation. The results show high spatial variability in temperature lapse rates (LRs) in different climatic contexts, with the steepest LRs located on the cold-dry northwestern Tibetan Plateau and the lowest LRs located on the warm-humid monsoonal-influenced southeastern Tibetan Plateau. Near-surface air temperatures in high-elevation glacierized regions of the western and central Tibetan Plateau are less influenced by katabatic winds and thus can be linearly extrapolated from off-glacier records. In contrast, the local katabatic winds prevailing on the temperate glaciers of the southeastern Tibetan Plateau exert pronounced cooling effects on the ambient air temperature, and thus, on-glacier air temperatures are significantly lower than that in elevation-equivalent nonglacierized regions. Consequently, linear temperature extrapolation from low-elevation nonglacierized stations may lead to as much as 40% overestimation of positive degree days, particularly with respect to large glaciers with a long flowline distances and significant cooling effects. These findings provide noteworthy evidence that the different LRs and relevant cooling effects on high-elevation glaciers under distinct climatic regimes should be carefully accounted for when estimating glacier melting on the Tibetan Plateau.

scholarly journals A Comparison of SNOTEL and GHCN/CRU Surface Temperatures with Free-Air Temperatures at High Elevations in the Western United States: Data Compatibility and Trends

2005 ◽  
Vol 18 (12) ◽  
pp. 1967-1985 ◽  
Author(s):  
N. C. Pepin ◽  
M. Losleben ◽  
M. Hartman ◽  
K. Chowanski
Keyword(s):  
Air Temperature ◽  
Temperature Difference ◽  
Warming Trend ◽  
High Elevation ◽  
Climatic Research Unit ◽  
Mountain Areas ◽  
Temperature Anomalies ◽  
Surface Temperatures ◽  
Air Temperatures ◽  
Free Air

Abstract This paper compares high-elevation surface temperatures based on the Global Historical Climate Network/Climatic Research Unit (GHCN/CRU) and snow telemetry (SNOTEL) datasets, with simultaneous free-air equivalent temperatures, interpolated from NCEP–NCAR reanalysis. Mean monthly temperature anomalies from 1982 to 1999 are examined for 60 SNOTEL and 296 GHCN/CRU sites at elevations over 500 m with relatively homogenous records. The surface/free-air temperature difference ΔT (Ts − Ta) is calculated for both the SNOTEL and GHCN/CRU datasets. Topography influences the correlation between surface and free-air temperature anomalies. Physically realistic diurnal and seasonal changes in ΔT\E are illustrated. Systematic secular trends in surface temperatures, free-air temperatures, and ΔT are revealed, but the sign and magnitude of change depends on location, meaning that regional signals are weak. The Ts trends are positive for most GHCN and CRU sites, and for SNOTEL sites at night. Daytime cooling in the SNOTEL network reduces the mean daily warming trend. The Ta trends are consistently positive for both networks and are often larger than Ts. Thus mean ΔT trends are negative for both datasets. The smaller sample size in the SNOTEL dataset means that error estimates for regional signals are much wider than for the GHCN/CRU dataset. Trend difference maps identify potentially anomalous SNOTEL records. Trends show no correlation with elevation and topography. Surface trends show higher variability and account for most of the uncertainty in ΔT trends. Sensitivity of trends to time period is also discussed. Such changes in the free-air/surface temperature difference may indicate change in the energy balance of mountain areas.

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