Late Wisconsin/Early Holocene Vegetation in the Bonneville Basin

1995 ◽  
Vol 44 (2) ◽  
pp. 246-256 ◽  
Author(s):  
David Rhode ◽  
David B. Madsen
Keyword(s):  
Climatic Conditions ◽  
Early Holocene ◽  
Sagebrush Steppe ◽  
Vegetation Changes ◽  
Lake Bonneville ◽  
Limber Pine ◽  
Summer Temperatures ◽  
Bonneville Basin ◽  
Apparent Conflict ◽  
Desert Scrub

AbstractWoodrat middens from the northern Bonneville Basin allow a reconstruction of vegetation changes from 14,000 to 9000 yr ago. Cold montane steppe, dominated by sagebrush, covered much of the western Bonneville Basin prior to 13,000 yr ago. From 13,000-10,800 yr ago, the region was vegetated by limber pine woodlands in lower montane settings and a mosaic of limber pine and sagebrush steppe along basin flour margins. These low-elevation limber pine woodlands began to retreat upslope after about 11,000 yr ago due to increasingly drier climatic conditions, and were replaced by relatively more xeric desert scrub dominated by sagebrush and shadscale. The growth of limber pine at low elevations suggests that summer temperatures were as much as 6°C lower than at present. This evidence is in apparent conflict with the currently accepted post-Provo Lake Bonneville chronology, especially the magnitude of the postulated near-dessication of Lake Bonneville from ca. 13,000-12,200 yr ago.

Late Pleistocene and early Holocene rivers and wetlands in the Bonneville basin of western North America

2003 ◽  
Vol 60 (2) ◽  
pp. 200-210 ◽  
Author(s):  
Charles G. Oviatt ◽  
David B. Madsen ◽  
Dave N. Schmitt
Keyword(s):  
Great Basin ◽  
Late Pleistocene ◽  
Theoretical Models ◽  
Coarse Sand ◽  
Early Holocene ◽  
River Channels ◽  
Human Occupation ◽  
Lake Bonneville ◽  
River Bed ◽  
Bonneville Basin

AbstractField investigations at Dugway Proving Ground in western Utah have produced new data on the chronology and human occupation of late Pleistocene and early Holocene lakes, rivers, and wetlands in the Lake Bonneville basin. We have classified paleo-river channels of these ages as “gravel channels” and “sand channels.” Gravel channels are straight to curved, digitate, and have abrupt bulbous ends. They are composed of fine gravel and coarse sand, and are topographically inverted (i.e., they stand higher than the surrounding mudflats). Sand channels are younger and sand filled, with well-developed meander-scroll morphology that is truncated by deflated mudflat surfaces. Gravel channels were formed by a river that originated as overflow from the Sevier basin along the Old River Bed during the late regressive phases of Lake Bonneville (after 12,500 and prior to 11,000 14C yr B.P.). Dated samples from sand channels and associated fluvial overbank and wetland deposits range in age from 11,000 to 8800 14C yr B.P., and are probably related to continued Sevier-basin overflow and to groundwater discharge. Paleoarchaic foragers occupied numerous sites on gravel-channel landforms and adjacent to sand channels in the extensive early Holocene wetland habitats. Reworking of tools and limited toolstone diversity is consistent with theoretical models suggesting Paleoarchaic foragers in the Old River Bed delta were less mobile than elsewhere in the Great Basin.

Climate forcing of volcano lateral collapse: evidence from Mount Etna, Sicily

2010 ◽  
Vol 368 (1919) ◽  
pp. 2559-2577 ◽  
Author(s):  
K. R. Deeming ◽  
B. McGuire ◽  
P. Harrop
Keyword(s):  
Slope Failure ◽  
Climatic Conditions ◽  
Early Holocene ◽  
Mount Etna ◽  
Watershed Development ◽  
Eastern Flank ◽  
Consequent Reduction ◽  
Water Saturated ◽  
Excess Pore Pressures ◽  
Exposure Ages

In this study, we present evidence for early Holocene climatic conditions providing circumstances favourable to major lateral collapse at Mount Etna, Sicily. The volcano’s most notable topographic feature is the Valle del Bove, a 5×8 km cliff-bounded amphitheatre excavated from the eastern flank of the volcano. Its origin due to prehistoric lateral collapse is corroborated by stürtzstrom deposits adjacent to the amphitheatre’s downslope outlet, but the age, nature and cause of amphitheatre excavation remain matters for debate. Cosmogenic 3 He exposure ages determined for eroded surfaces within an abandoned watershed flanking the Valle del Bove support channel abandonment ca 7.5 ka BP, as a consequence of its excavation in a catastrophic collapse event. Watershed development was largely dictated by pluvial conditions during the early Holocene, which are also implicated in slope failure. A viable trigger is magma emplacement into rift zones in the eastern flank of a water-saturated edifice, leading to the development of excess pore pressures, consequent reduction in sliding resistance, detachment and collapse. Such a mechanism is presented as one potential driver of future lateral collapse in volcanic landscapes forecast to experience increased precipitation or melting of ice cover as a consequence of anthropogenic warming.

scholarly journals A preliminary study of the behaviour of water buffaloes (<i>Bubalus bubalis</i>) imported to Poland (Short Communication)

2012 ◽  
Vol 55 (5) ◽  
pp. 415-419 ◽  
Author(s):  
I. Antkowiak ◽  
J. Pytlewski ◽  
A. Purczyńska ◽  
R. Skrzypek
Keyword(s):  
Short Communication ◽  
Growing Season ◽  
Bubalus Bubalis ◽  
Climatic Conditions ◽  
Drainage Ditch ◽  
Short Period ◽  
Summer Temperatures ◽  
Preliminary Study ◽  
Time Of Year ◽  
Lying Down

Abstract. This study was carried out on 26 adult water (river) buffaloes (25 females and 1 male) imported in 2006 to an eco-tourism farm in the Wielkopolska province, Poland. During the growing season, animals were kept on a logged pasture covering an area of about 15 ha. The pasture was divided into three approximately equal parts, each with a different facility available for wallowing; i.e. pond, drainage ditch and stream. Behavioural observations were carried out three times in July and August 2007 in approximately 14-d intervals, each time during one day on a different part of the pasture, always between 06.00 and 16.00. The method of registration was instantaneous scan sampling, performed at approximately 60 min intervals. On the days of observations mean daily temperature varied from 20.2 to 20.8 °C. Grazing was the behaviour shown by the highest percentage of animals in the herd (58.6%), followed by rumination (28.2%), lying down (26.5%), wallowing (12.9%) and standing (1.4%). When they had access to a pond or ditch, the proportion of animals wallowing was twice as much compared to stream access (P<0.05). It was concluded that the welfare of the investigated buffaloes was not compromised during the high summer temperatures that can be encountered in Poland. Results also indicate that the highest level of welfare can be reached in this time of year when animals are provided with access to ample facility for wallowing. Under our climatic conditions facilities with still or slowly moving water appeared to be preferred by river buffaloes. However, this study has a limitation which is short period of observation, thus it is possible that a longer and more representative period of observations could change these conclusions.

scholarly journals How dry was the Younger Dryas? Evidence from a coupled <i>δ</i><sup>2</sup>H–<i>δ</i><sup>18</sup>O biomarker paleohygrometer applied to the Gemündener Maar sediments, Western Eifel, Germany

2019 ◽  
Vol 15 (2) ◽  
pp. 713-733 ◽  
Author(s):  
Johannes Hepp ◽  
Lorenz Wüthrich ◽  
Tobias Bromm ◽  
Marcel Bliedtner ◽  
Imke Kathrin Schäfer ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Younger Dryas ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Leaf Water ◽  
Early Holocene ◽  
Unexpected Finding ◽  
Temperature Dependent ◽  
The Past ◽  
Natural Climate

Abstract. Causes of the Late Glacial to Early Holocene transition phase and particularly the Younger Dryas period, i.e. the major last cold spell in central Europe during the Late Glacial, are considered to be keys for understanding rapid natural climate change in the past. The sediments from maar lakes in the Eifel, Germany, have turned out to be valuable archives for recording such paleoenvironmental changes. For this study, we investigated a Late Glacial to Early Holocene sediment core that was retrieved from the Gemündener Maar in the Western Eifel, Germany. We analysed the hydrogen (δ2H) and oxygen (δ18O) stable isotope composition of leaf-wax-derived lipid biomarkers (n-alkanes C27 and C29) and a hemicellulose-derived sugar biomarker (arabinose), respectively. Both δ2Hn-alkane and δ18Osugar are suggested to reflect mainly leaf water of vegetation growing in the catchment of the Gemündener Maar. Leaf water reflects δ2H and δ18O of precipitation (primarily temperature-dependent) modified by evapotranspirative enrichment of leaf water due to transpiration. Based on the notion that the evapotranspirative enrichment depends primarily on relative humidity (RH), we apply a previously introduced “coupled δ2Hn-alkane–δ18Osugar paleohygrometer approach” to reconstruct the deuterium excess of leaf water and in turn Late Glacial–Early Holocene RH changes from our Gemündener Maar record. Our results do not provide evidence for overall markedly dry climatic conditions having prevailed during the Younger Dryas. Rather, a two-phasing of the Younger Dryas is supported, with moderate wet conditions at the Allerød level during the first half and drier conditions during the second half of the Younger Dryas. Moreover, our results suggest that the amplitude of RH changes during the Early Holocene was more pronounced than during the Younger Dryas. This included the occurrence of a “Preboreal Humid Phase”. One possible explanation for this unexpected finding could be that solar activity is a hitherto underestimated driver of central European RH changes in the past.

Observations and Experiments on some Larval Trematodes of Freshwater Snails and Fish from Southern Iceland

1973 ◽  
Vol 47 (4) ◽  
pp. 409-414 ◽  
Author(s):  
David Blair
Keyword(s):  
Life Cycle ◽  
Liver Fluke ◽  
Migratory Birds ◽  
Fasciola Hepatica ◽  
Climatic Conditions ◽  
Life Cycles ◽  
Freshwater Snails ◽  
Apparent Absence ◽  
Summer Temperatures

During the Glasgow University Iceland Expedition in 1972 freshwater snails and fish in southern Iceland were sampled for larval trematodes. This survey was prompted by the lack of literature concerning larval trematodes there. Indeed, the apparent absence of liver fluke Fasciola hepatica (L.1758) from Iceland, (Palsson, pers. comm.) despite the presence of its molluscan and definitive hosts and the low summer temperatures, might lead to the supposition that climatic conditions are too harsh to permit completion of many trematode life-cycles. A number of adult trematodes have been reported from migratory birds in Iceland (Brinkmann 1956), although these parasites could have been acquired elsewhere. However, Crepidostomum farionis (Müller, 1784) from the gut of trout and char in Iceland (Brinkmann 1956) presumably completes its life cycle in freshwater there, although this has yet to be demonstrated.

A multiproxy study of Younger Dryas and Early Holocene climatic conditions from the Grabia River paleo-oxbow lake (central Poland)

2015 ◽  
Vol 438 ◽  
pp. 34-50 ◽  
Author(s):  
Dominik Pawłowski ◽  
Mateusz Płóciennik ◽  
Stephen J. Brooks ◽  
Tomi P. Luoto ◽  
Krystyna Milecka ◽  
...  
Keyword(s):  
Younger Dryas ◽  
Climatic Conditions ◽  
Early Holocene ◽  
Oxbow Lake ◽  
Central Poland

scholarly journals The Impact of Morphological Features on Summer Temperature Variations on the Example of two Residential Neighborhoods in Ljubljana, Slovenia

2017 ◽  
Author(s):  
Alenka Fikfak ◽  
Saja Kosanović ◽  
Miha Konjar ◽  
Janez P. Grom ◽  
Martina Zbašnik-Senegačnik
Keyword(s):  
Thermal Imaging ◽  
Urban Morphology ◽  
Climatic Conditions ◽  
Satellite Imaging ◽  
Summer Temperatures ◽  
Urban Heat ◽  
Study Methodology ◽  
The Impact ◽  
The City

The study conducted in this paper is focused on a predominantly residential area of the City of Ljubljana &ndash; Koseze, which is characterized by generally favorable (bio)climatic conditions. Nonetheless, thermal satellite imaging showed that residential neighborhoods within the Koseze district display unexpected variations in summer temperatures. This observation called into question the benefits of existing bioclimatic features and indicated the need to investigate and compare two neighborhoods with similar urban parameters, with the aim to identify morphological differential characteristics impacting urban heat island (UHI) intensity. By applying the study methodology based on a literature review, surveys of key precedents, detailed mapping in two Koseze locations, in situ measurements, observations and recordings, thermal imaging and the analyses of statistical data, as well as by defining the four main categories of morphological urban parameters &ndash; structure, cover, fabric and metabolism, it was concluded that both neighborhoods have common morphological elements mitigating the UHI effect. Additionally, it was found that the neighborhood with higher UHI intensity has several less favorable features, such as busier roads, larger surface of parking corridors, and the existence of underground parking space. The traffic as an element of urban morphology hence represents the main cause of differences among UHI levels in the two Koseze neighborhoods.

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