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301.
James R. Farmer Charles Chancellor Jacob Brenner James Whitacre Eric G. Knackmuhs 《The Professional geographer》2016,68(4):584-594
Clearly understanding the connections among land use, demographics, and sensitivity and engagement with natural areas can provide insight into landowner decision making. Pertinent findings from our mailed survey of landowners in Brown County, Indiana, include that (1) individuals already engaged in land conservation or environmental activities are most likely to consider a conservation easement (CE), (2) hunters and anglers are less likely to have interest in CEs, and (3) few differences exist between seasonal and permanent residents. Among other things, this research highlights the significance for landowner willingness to grant a CE of involving landowners in conservation activities and environmental organizations. 相似文献
302.
Magnetic sector mass spectrometers dominate the field of 40Ar/39Ar geochronology. Recent advances in quadrupole mass spectrometer technology, especially improvements in resolution, have increased the performance of these instruments to the extent that they can be used for isotopic determinations. We describe a triple filter quadrupole mass spectrometer (Hiden HAL 3F Series Pulse Ion Counting Triple Filter QMS) linked to an automated furnace extraction and cleaning system dedicated to 40Ar/39Ar incremental heating experiments.The instrument produces peaks with broad flat tops and a width of 0.9 amu at 10 cps height and 0.84 amu at 500,000 cps height on a 1 million cps high peak (peak width at 0.01‰ and 50% peak height respectively). This allows measurement of ratios of the main Ar peaks in the 1‰ range. Measurements of 1.6 × 10?12 mole of air reference gas over two years yields 40Ar/36Ar = 257.9 ± 1.3 (1σ, n = 34). The ability of the instrument to produce 40Ar/39Ar ages from rocks/minerals of a wide age range, reaching into the late Quaternary, are demonstrated by a series of tests and comparison with geochronological data from other studies and an in-house MAP 215-50 magnetic sector mass spectrometer. We demonstrate that high-end quadrupole systems can be used for routine 40Ar/39Ar dating purposes. 相似文献
303.
Jayde N. Hirniak Eugene I. Smith Racheal Johnsen Minghua Ren Jamie Hodgkins Caley Orr Fabio Negrino Julien Riel-Salvatore Shelby Fitch Christopher E. Miller Andrea Zerboni Guido S. Mariani Jacob A. Harris Claudine Gravel-Miguel David Strait Marco Peresani Stefano Benazzi Curtis W. Marean 《第四纪科学杂志》2020,35(1-2):199-212
Chemical characterization of cryptotephra is critical for temporally linking archaeological sites. Here, we describe cryptotephra investigations of two Middle–Upper Paleolithic sites from north-west Italy, Arma Veirana and Riparo Bombrini. Cryptotephra are present as small (<100 µm) rhyolitic glass shards at both sites, with geochemical signatures rare for volcanoes in the Mediterranean region. Two chemically distinct shard populations are present at Arma Veirana (P1 and P2). P1 is a high silica rhyolite (>75 wt.%) with low FeO (<1 wt.%) and a K2O/Na2O > 1 and P2 is also a high silica rhyolite (>75 wt.%) but with higher FeO (2.33–2.65 wt.%). Shards at Riparo Bombrini (P3) are of the same composition as P1 shards at Arma Veirana, providing a distinct link between deposits at both sites. Geochemical characteristics suggest three possible sources for P1 and P3: eruptions from Lipari Island (56–37.7 ka) in Italy, the Acigöl volcanic field (200–20 ka) in Turkey and the Miocene Kirka-Phrigian caldera (18 Ma) in Turkey. Eruptions from Lipari Island are the most likely source for P1,3 cryptotephra. This study highlights how cryptotephra can benefit archaeology, by providing a direct link between Arma Veirana and Riparo Bombrini as well as other deposits throughout the Mediterranean. 相似文献
304.
305.
Glaciological Features in the Initial Quiescent Phase of Kuannersuit Glacier, Greenland 总被引:1,自引:0,他引:1
Jacob Clement Yde N. Tvis Knudsen 《Geografiska Annaler: Series A, Physical Geography》2005,87(3):473-485
This paper describes glaciological features observed on the surface of the large outlet glacier Kuannersuit Glacier on Disko Island, West Greenland, during its initial quiescent phase after a major surge event occurred in 1995–98 in order to classify the glaciomorphological surge system. Focus is on surge features either associated with active surging such as a propagating surge front and serac formation or formed as a consequence of surging such as looped medial moraines and potholes; and on hydrological features related to the evolution of the glacier drainage system such as the supraglacial routing, moulin types and chasms. A chronological glaciomorphological model of the initial quiescent phase of Kuannersuit Glacier, which can be regarded as representative for large outlet surge‐type glaciers with terrestrial terminal regime and long quiescent phase, is proposed. 相似文献
306.
307.
Morphological instabilities in periodic patterns occurring both in precipitation and crystallization processes (Liesegang rings and crystal zoning) are investigated and compared with similar patterns in geological samples (zebra rocks and mud bands in snow sediments). In classical Liesegang systems, undisturbed parallel or concentric precipitation bands are emanated from even or concentric diffusion sources in homogeneous diffusion matrices of gelatine or other gels. In the case of superposing diffusion sources, sources with undulatory curvatures or local diffusion barriers there may occur several types of instabilities within the sequence of regular patterns: (a) gaps within the bands forming radial alleys free of precipitate, (b) transition from broken bands to speckled patterns and (c) apparent branching of bands linked together by so-called anastomoses. Calculations with a competitive particle growth (CPG) model show that lateral instabilities in Liesegang bands (gaps and radial alleys of gaps) are the result of Ostwald ripening effects taking place after precipitation. Apparent branching of bands or formation of anastomoses can be simulated with a prenucleation model according to Ostwald's supersaturation theory. Similar irregularities can be observed in zebra rocks (e.g. banded siderite) whose bandings are commonly explained by sequential sedimentation processes. A very different mechanism is assumed to be responsible for the origin of mud bands in snow sediments. An initially homogeneous distribution of intrinsic mud in snow sediments can be arranged into parallel bands according to a crystal zoning mechanism which is based on repeated thawing and freezing of the snow sediment due to the daily alternation of sun and darkness. 相似文献
308.
Breetzke Gregory D. Fabris-Rotelli Inger Modiba Jacob Edelstein Ian S. 《GeoJournal》2021,86(2):765-776
GeoJournal - Schools are unique places that greatly influence the daily lives of learners. Examining any factors that may be contributing to school absenteeism and dropout rates is vital as gaining... 相似文献
309.
310.
E.?AldrianEmail author L.?Dümenil-Gates D.?Jacob R.?Podzun D.?Gunawan 《Climate Dynamics》2004,22(8):795-814
Simulations of the Indonesian rainfall variability using the Max Planck Institute regional climate model REMO have been performed using three different lateral boundary forcings: Reanalyses from the European Centre for Medium-Range Weather Forecasts (ERA15), the National Centers for Environmental Prediction and National Center for Atmospheric Research (NRA) as well as from ECHAM4 climate model simulation. The result of those simulations are compared to station data. REMO simulations were performed at 0.5° horizontal resolution for the whole archipelago and at 1/6° for Sulawesi Island. In general the REMO model, reproduces the spatial pattern of monthly and seasonal rainfall well over land, but overestimates the rainfall over sea. Superiority of REMO performance over land is due to a high-resolution orography, while over sea, REMO suffers from erroneously low surface fluxes. REMO reproduces variability during El Niño-Southern Oscillations years well but fails to show a good (wet and dry) monsoon contrast. Despite strong influences of the lateral boundary fields, REMO shows a realistic improvement of a local phenomenon over Molucca. Significant improvement for the step from the relatively high global 1.125° to 0.5° resolution is noticeable, but not from 0.5° into 1/6°. The REMO simulation driven by ERA15 has the best quality, followed by NRA and ECHAM4 driven simulations. The quality of ERA15 is the main factor determining the quality of REMO simulations. A predictability study shows small internal variability among ensemble members. However, there are systematic intrinsic climatological errors as shown in the predictability analysis. These intrinsic errors have monthly, seasonal and regional dependencies and the one over Java is significantly large. The intrinsic error study suggests the presence of the spring predictability barrier and a high level of predictability in summer. 相似文献