Terminal Pleistocene/Early Holocene Environmental Change at the Sunshine Locality, North-Central Nevada, U.S.A.     

Gary Huckleberry  Charlotte Beck  George T. Jones  Amy Holmes  Michael Cannon  Stephanie Livingston  Jack M. Broughton 《Quaternary Research》2001,55(3):303

Sedimentological, faunal, and archaeological investigations at the Sunshine Locality, Long Valley, Nevada reveal a history of human adaptation and environmental change at the last glacial–interglacial transition in North America's north-central Great Basin. The locality contains a suite of lacustrine, alluvial, and eolian deposits associated with fluvially reworked faunal remains and Paleoindian artifacts. Radiocarbon-dated stratigraphy indicates a history of receding pluvial lake levels followed by alluvial downcutting and subsequent valley filling with marsh-like conditions at the end of the Pleistocene. A period of alluvial deposition and shallow water tables (9,800 to 11,000 ¹⁴C yr B.P.) correlates to the Younger Dryas. Subsequent drier conditions and reduced surface runoff mark the early Holocene; sand dunes replace wetlands by 8,000 ¹⁴C yr B.P. The stratigraphy at Sunshine is similar to sites located 400 km south and supports regional climatic synchroneity in the central and southern Great Basin during the terminal Pleistocene/early Holocene. Given regional climate change and recurrent geomorphic settings comparable to Sunshine, we believe that there is a high potential for buried Paleoindian features in primary association with extinct fauna elsewhere in the region yet to be discovered due to limited stratigraphic exposure and consequent low visibility.  相似文献   

The water balance of a small lake using stable isotopes and tritium   总被引：2，自引：0，他引：2  

J.V. Turner  G.B. Allison  J.W. Holmes 《Journal of Hydrology》1984,70(1-4):199-220

A small maar lake, known as the Blue Lake, set in a karstic region of southeastern Australia, provides the municipal water supply for a population of 20,000. The lake has a volume of 3.6·10⁷m³, of which 10–15% is pumped from it each year. The lake is recharged almost entirely from groundwater and the main objective of this study was to estimate the total groundwater inflow and outflow rates. Estimation of groundwater throughflow in a lake is difficult to assess using classical hydrological techniques and an alternative method involving measurement of the concentrations of the environmental isotopes ³H, ¹⁸O, ²H and ¹⁴C in the lake water and in the recharging groundwater was used to establish the lake-water balance. The water-balance calculations indicated a total groundwater inflow to Blue Lake of between 5.0·10⁶ and 6.5·10⁶m³yr.⁻¹, corresponding to a residence time of water in the lake of 6 yr. It was not possible to derive the relative proportions of inflow to the lake from the two possible source aquifers, using these isotopes, because their concentrations did not show a sufficiently large contrast to distinguish the two water sources.  相似文献   

Trace-element and stable-isotope geochemistry of non-marine ostracod shells in Quaternary palaeoenvironmental reconstruction   总被引：5，自引：0，他引：5  

Jonathan A. Holmes 《Journal of Paleolimnology》1996,15(3):223-235

Ostracods are small bivalved aquatic crustancean. They secrete shells of low-Mg calcite that are often preserved in lake sediments. Recent work has shown that the uptake of trace elements (especially Mg and Sr) into the shell may be a function of the salinity and temperature of the host water. Furthermore, ostracod shells are a source of carbonate for stable-isotope analysis. This paper reviews the application of ostracod shell chemistry to Quaternary palaeolimnology. Although such work has revealed the excellent potential of these techniques to provide quantitative palaeolimnological reconstructions, a number of problems have also emerged. These problems relate to (1) methods used for extraction of ostracod shells from sediment and their subsequent cleaning (2) post-mortem diagenesis and alteration of the shell (3) complications with the calcification mechanism (4) spatial and temporal variability in shell composition (5) the ecological tolerances of individual species and (6) the relationships between shell chemistry and palaeohydrology. To some extent, these problems are an inevitable outcome of the diversity of lacustrine systems: they may be overcome by developing a thorough understanding of the physiology, life-cycle and ecology of the species concerned, together with the modern limnology of the study site. Overall, these techniques have excellent potential in Quaternary palaeolimnology, especially when used with other palaeoenvironmental indicators.  相似文献   

National and Community Market Contributions of Wilderness     

Evan Hjerpe  Tom Holmes  Eric White 《社会与自然资源》2017,30(3):265-280

Wilderness attracts tourists and generates visitor spending in proximate communities as people enjoy Wilderness for outdoor recreation. Wilderness also attracts amenity migrants and out-of-region investments into surrounding regional economies. To investigate the amount and types of employment and income generated by Wilderness visitation, we conducted an economic contribution analysis of aggregate national visitor expenditures. The U.S. Forest Service National Visitor Use and Monitoring (NVUM) economic spending profiles were used to construct types and amounts of Wilderness visitor spending and were applied to an estimated 9.9 million annual visitors across federal agencies. IMPLAN modeling software was used to estimate total effects and multipliers for output, employment, income, and value added. Results show that some $500 million is annually spent in communities adjacent to Wilderness, generating a direct effect of 5,700 jobs and a total output effect over $700 million across numerous industries ($2012 including indirect and induced effects).  相似文献   

Impact of diagenesis on reservoir quality in a sedimentary geothermal play: a case study in the Cooper Basin,South Australia          下载免费PDF全文

Antoine Dillinger  Ludovic P. Ricard  Cameron Huddlestone‐Holmes  Lionel Esteban 《Basin Research》2016,28(2):252-272

Geothermal resources hosted within sedimentary basins with high natural permeability have been targeted for the production of energy in Australia. The Hutton Sandstone (Cooper‐Eromanga Basin) – a prolific oil and gas producer known to have good reservoir quality and high reservoir volume – was recently tested for its geothermal potential in the Cooper Region. However, recent exploratory drilling did not produce the anticipated flow rates, raising the question of the impact of diagenesis on the reservoir quality of this sedimentary formation. The combined characterization of the petrology, diagenesis and petrophysical properties of the Hutton Sandstone at Celsius‐1 and other surrounding wells indicates variable reservoir properties in the Cooper Region. This integrated study demonstrates that low formation permeability occurs at geothermal target depth and explains the negligible flow rates obtained at Celsius‐1. These low permeabilities are the results of the preservation of widespread detrital clayey matrix and the extensive occurrence of authigenic kaolinite, illite and silica cements at the top and base of the Hutton Sandstone. This aspect is confirmed by NMR T₂ transversal relaxation time becoming shorter at similar depths. Petrography analysis also reveals that sandstones are affected by diagenetic processes of the eogenetic and mesogenetic phases. However, the Hutton Sandstone at Celsius‐1 is presently at pressure‐temperature conditions that are below the mesogenetic conditions, which suggests a late episode of uplift and cooling from maximum palaeotemperatures.  相似文献   

Natural hazards in Australia: storms,wind and hail     

Kevin Walsh  Christopher J. White  Kathleen McInnes  John Holmes  Sandra Schuster  Harald Richter  Jason P. Evans  Alejandro Di Luca  Robert A. Warren 《Climatic change》2016,135(1):55-68

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Excursion to Sheppey: Saturday,July 16th, 1898     

W. Whitaker  T.V. Holmes  W.H. Shrubsole  A.E. Salter 《Proceedings of the Geologists' Association. Geologists' Association》1898,15(10):459-462

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Preneoplastic cellular changes associated with exposure to environmental contaminants in Puget Sound, Washington     

M.L. Landolt  E.H. Holmes  G.K. Ostrander 《Marine environmental research》1985,17(2-4)

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Environmental controls on modern chironomid faunas from NW Iceland and implications for reconstructing climate change   总被引：1，自引：1，他引：0  

Peter G. Langdon  Naomi Holmes  Chris J. Caseldine 《Journal of Paleolimnology》2008,40(1):273-293

Reconstructing climate change quantitatively over millennial timescales is crucial for understanding the processes that affect the climate system. One of the best methods for producing high resolution, low error, quantitative summer air temperature reconstructions is through chironomid analyses. We analysed over 50 lakes from NW and W Iceland covering a range of environmental gradients in order to test whether the distribution of the Icelandic chironomid fauna was driven by summer temperature, or whether other environmental factors were more dominant. A range of analyses showed the main environmental controls on chironomid communities to be substrate (identified through loss-on-ignition and carbon content) and mean July air temperature, although other factors such as lake depth and lake area were also important. The nature of the Icelandic landscape, with numerous volcanic centres (many of which are covered by ice caps) that produce large quantities of ash, means that relative lake carbon content and summer air temperature do not co-vary, as they often do in other chironomid datasets within the Arctic as well as more temperate environments. As the chironomid–environment relationships are thus different in Iceland compared to other chironomid training sets, we suggest that using an Icelandic model is most appropriate for reconstructing past environmental change from fossil Icelandic datasets. Analogue matching of Icelandic fossil chironomid datasets with the Icelandic training set and another European chironomid training set support this assertion. Analyses of a range of chironomid-inferred temperature transfer functions suggest the best to be a two component WA-PLS model with r ² _jack = 0.66 and RMSEP = 1.095°C. Using this model, chironomid-inferred temperature reconstructions of early Holocene Icelandic sequences show the magnitude of temperature change compared to contemporary temperatures to be similar to other NW European chironomid sequences, suggesting that the predictive power of the model is good.  相似文献   

Global Soil Moisture Patterns Observed by Space Borne Microwave Radiometers and Scatterometers   总被引：3，自引：0，他引：3  

R. A. M. de Jeu  W. Wagner  T. R. H. Holmes  A. J. Dolman  N. C. van de Giesen  J. Friesen 《Surveys in Geophysics》2008,29(4-5):399-420

Within the scope of the upcoming launch of a new water related satellite mission (SMOS) a global evaluation study was performed on two available global soil moisture products. ERS scatterometer surface wetness data was compared to AMSR-E soil moisture data. This study pointed out a strong similarity between both products in sparse to moderate vegetated regions with an average correlation coefficient of 0.83. Low correlations were found in densely vegetated areas and deserts. The low values in the vegetated regions can be explained by the limited soil moisture retrieval capabilities over dense vegetation covers. Soil emission is attenuated by the canopy and tends to saturate the microwave signal with increasing vegetation density, resulting in a decreased sensor sensitivity to soil moisture variations. It is expected that the new low frequency satellite mission (SMOS) will obtain soil moisture products with a higher quality in these regions. The low correlations in the desert regions are likely due to volume scattering or to the dielectric dynamics within the soil. The volume scattering in dry soils causes a higher backscatter under very dry conditions than under conditions when the sub-surface soil layers are somewhat wet. In addition, at low moisture levels the dielectric constant has a reduced sensitivity in response to changes in the soil moisture content. At a global scale the spatial correspondence of both products is high and both products clearly distinguish similar regions with high seasonal and inter annual variations. Based on the global analyses we concluded that the quality of both products was comparable and in the sparse to moderate vegetated regions both products may be beneficial for large scale validation of SMOS soil moisture. Some limitations of the studied products are different, pointing to significant potential for combining both products into one superior soil moisture data set.  相似文献