Determining the unfrozen water content in soils by time‐domain reflectometry: Research note     

M.W. Smith  D.E. Patterson 《大气与海洋》2013,51(2):261-263

Abstract

Experimental data are presented for a variety of soils that establish a relationship between the measured dielectric constant and the volumetric unfrozen water content. The relationship is essentially the same as that determined by Topp et al. (1980) for unfrozen soils.  相似文献   

The Equal Earth map projection     

Bojan Šavrič  Tom Patterson 《International journal of geographical information science》2019,33(3):454-465

The Equal Earth map projection is a new equal-area pseudocylindrical projection for world maps. It is inspired by the widely used Robinson projection, but unlike the Robinson projection, retains the relative size of areas. The projection equations are simple to implement and fast to evaluate. Continental outlines are shown in a visually pleasing and balanced way.  相似文献   

Global geological mapping of Ganymede     

G. Wesley Patterson  Geoffrey C. Collins  Robert T. Pappalardo  Baerbel K. Lucchitta 《Icarus》2010,207(2):845-867

We have compiled a global geological map of Ganymede that represents the most recent understanding of the satellite based on Galileo mission results. This contribution builds on important previous accomplishments in the study of Ganymede utilizing Voyager data and incorporates the many new discoveries that were brought about by examination of Galileo data. We discuss the material properties of geological units defined utilizing a global mosaic of the surface with a nominal resolution of 1 km/pixel assembled by the USGS with the best available Voyager and Galileo regional coverage and high resolution imagery (100-200 m/pixel) of characteristic features and terrain types obtained by the Galileo spacecraft. We also use crater density measurements obtained from our mapping efforts to examine age relationships amongst the various defined units. These efforts have resulted in a more complete understanding of the major geological processes operating on Ganymede, especially the roles of cryovolcanic and tectonic processes in the formation of might materials. They have also clarified the characteristics of the geological units that comprise the satellite’s surface, the stratigraphic relationships of those geological units and structures, and the geological history inferred from those relationships. For instance, the characteristics and stratigraphic relationships of dark lineated material and reticulate material suggest they represent an intermediate stage between dark cratered material and light material units.  相似文献   

The Matuyama-Brunhes reversal at Tecopa basin, southeastern California, revisited again     

Edwin E. Larson  Penny E. Patterson 《Earth and Planetary Science Letters》1993,120(3-4):311-325

Numerous records of the Matuyama-Brunhes geomagnetic transition have been obtained from paleomagnetic studies. Because few of the reversal records are of acceptable reliability, however, the exact behavior of the field during the transition has remained enigmatic. To provide confirmation of one of the more reliable records, we have re-examined the transition at two sites, 150 m apart, in lake sediments of Tecopa basin, southeastern California. The two sites are geographically very close to that of Valet et al. [10], who previously obtained a record from that site indicating that the transitional field was non-dipolar and axisymmetric.

The Matuyama-Brunhes reversal is recorded differently at each of our two sites and at that of Valet et al. [10]. Zones of mixed polarities and/or intermediate directions occur at all three sites but they differ greatly in polarity character, thickness and stratigraphic position. It appears that all three sites have provided mutually contradictory records of the transition. It is unlikely, therefore, that any of the records is acceptable for establishing the nature of the transition at this locality.

Obliteration of the transition is apparently the result of acquisition of a stable, normal-polarity overprint that appears to consist of two remanence components, one acquired during post-depositional compaction and dewatering, and one during later sediment diagenesis.  相似文献   

Solar noble gases in the Earth: The systematics of helium-neon isotopes in mantle derived samples   总被引：2，自引：0，他引：2  

Masahiko Honda  Ian McDougall  Desmond Patterson 《Lithos》1993,30(3-4):257-265

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Acceptance speech for the V. M. Goldschmidt medal     

Clair C. Patterson 《Geochimica et cosmochimica acta》1981,45(8):1385-1388

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The circumvention of the natural biopurification of calcium along nutrient pathways by atmospheric inputs of industrial lead     

Robert W. Elias  Yoshimitsu Hirao  Clair C. Patterson 《Geochimica et cosmochimica acta》1982,46(12):2561-2580

Biopurification factors for Ca with respect to Sr, Ba, and natural, uncontaminated Pb were measured for different nutrient-consumer pairs in a remote subalpine ecosystem. The factor for Sr is expressed as: (nutrient $\text{Sr}\text{Ca}$) ÷ (consumer $\text{Sr}\text{Ca}$). Similar expressions were used for $\text{Ba}\text{Ca}$ and $\text{Pb}\text{Ca}$. It was found that Ca was biopurified of Sr 3-fold, of Ba 16-fold, and of Pb 100-fold in going from rock to sedge leaves. In going from sedge leaf to vole, Ca was biopurified of Sr 4-fold, of Ba 8-fold, and of Pb 16-fold. In going from meadow vole to pine marten, Ca was biopurified of Sr 6-fold, of Ba 7-fold, and of Pb 1.1-fold. Similar ranges of values for these factors were obtained for detrital and amphibian food chains. Fluxes of industrial lead entering the ecosystem as precipitation and dry deposition were measured and it was found that 40% of the lead in soil humus and soil moisture, 82% of the lead in sedge leaves, 92% of the lead in vole, and 97% of the lead in marten was industrial. The natural skeletal $\text{Pb}\text{Ca}$ ratio in carnivores (4 × 10^?8) was determined by means of corrections for inputs of industrial lead, food chain relationships, and measured biopurification factors for the ecosystem studied. This represents a 1700-fold reduction of the average $\text{Pb}\text{Ca}$ ratio in igneous rocks at the earth's surface (6.4 × 10^?5) by the compounding of successive Pb biopurification factors in transferring Ca from rock to carnivore. The natural ratio is similar to the value of 6 × 10^?8 observed for $\text{Pb}\text{Ca}$ in the bones of Peruvians who lived 2000 years ago but is 1/900th of the value of about 3.5 × 10^?5 for the skeletal $\text{Pb}\text{Ca}$ ratio found in present day Americans.This study shows experimentally how the $\text{Ba}\text{Ca}$ ratio in average surface igneous rock (3 × 10^?3) has been reduced 800-fold through compounding of successive biopurification steps to provide the skeletal $\text{Ba}\text{Ca}$ ratio of about 4 × 10^?6 observed in humans. It also provides biopurification factors for Sr and Ba among a number of nutrient-consumer pairs which anthropologists can use to delineate degrees of herbivory in diets of hominids within the last 10,000 years.  相似文献   

Aerial perspective for shaded relief     

Bernhard Jenny  Tom Patterson 《制图学和地理信息科学》2021,48(1):21-28

ABSTRACT

Aerial perspective is an essential design principle for shaded relief that emphasizes high elevation terrain using strong luminance contrast and low elevations with low contrast. Aerial perspective results in a more expressive shaded relief and helps the reader to understand the structure of a landscape more easily. We introduce a simple yet effective method for adding aerial perspective to shaded relief that is easy to control by the mapmaker.  相似文献   

Late Holocene sea-level changes and isostatic crustal movements in Atlantic Canada     

W. Roland Gehrels  Glenn A. Milne  Jason R. Kirby  R. Timothy Patterson  D.F.Daniel F. Belknap 《Quaternary International》2004,120(1):79

It has long been recognised that sea levels along the shores of Atlantic Canada have been rising rapidly during the Holocene in response to isostatic crustal movements. New sea-level data for the Bay of Fundy coast of southern New Brunswick (Little Dipper Harbour) and the Atlantic coast of Nova Scotia (Chezzetcook Inlet) show that late Holocene average rates of sea-level rise in these areas have been 1.0 and 2.5 m per 1000 yr, respectively. Numerical model calculations suggest that the high rates of sea-level rise are due to crustal subsidence produced by the combined effects of Laurentide ice loading (forebulge collapse) and ocean loading of the Scotian shelf. Although ice loading is the dominant contributor to the regional sea-level pattern, ocean loading is also important, contributing up to 40% of the total crustal subsidence in some areas. Tide gauges record rates of sea-level rise during the 20^th century that are 0.7–1.9 mm/yr higher than late Holocene trends, with the highest residuals occurring in the Bay of Fundy.  相似文献   

Plate motion on Europa and nonrigid behavior of the Icy lithosphere: The Castalia Macula region     

G.W. Patterson  J.W. Head  R.T. Pappalardo 《Journal of Structural Geology》2006,28(12):2237

We have developed a generalized quantitative technique for determining the finite pole of rotation between two rigid plates and use it to critically examine differing reconstructions of a region surrounding a prominent dark spot on Europa, Castalia Macula. This region is located near the equator of Europa's trailing hemisphere and has been suggested as a site where crustal convergence may have occurred. Previous reconstructions of the region have indicated that a ridge set and/or a band-like complex that define a collection of tectonic plates in the region accommodated surface contraction. However, a critical examination of the differences between these reconstructions has been complicated by the lack of a finite pole of rotation for the plates involved in either reconstruction. We have applied our modeling technique, coupled with a detailed examination of the morphology and cross-cutting relationships involving this ridge set and band-like complex, to determine if a unique reconstruction exists for several tectonic plates in this region. The cross-cutting relationships involving the ridge set also allow us to test the general assumption that plates behave rigidly on Europa. Assuming rigid behavior, our results suggest that a unique reconstruction does exist, indicating the ridge set accommodated surface contraction. However, analysis performed to test the assumption of plate rigidity indicates that one or more of the plates in the region did not behave rigidly. This does not rule out surface contraction along the ridge set but does indicate that a component of nonrigid behavior must be considered.  相似文献