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21.
An Inceptisol and an Alfisol from Western Maryland were sampled by horizon and exposed to the elevated temperatures associated with heat transfer measured beneath campfires. Substantial loss in organic carbon and change in carbon stable isotope composition was observed, even after exposure to relatively low temperatures (200–400 °C). Analyses showed that a comparison of carbon isotope enrichment in organic matter beneath a suspected campfire site to that of unaltered soil would give quantitative information about the minimum effective campfire temperature. Application of these results may lead to particular insight for archaeological sites where soil surfaces have been eroded or otherwise truncated.  相似文献   
22.
Pollen and non-pollen palynomorphs from two zoomorphic Kura-Araxes vessels (ca. 3000 b.c.) from Aradetis Orgora suggest they were utilized for the ritual consumption of wine and likely represent the beginning of the enduring tradition of animal-shaped wine-drinking containers in Georgia. This hypothesis is supported by archaeological and geoarchaeological data: they resemble later wine-containing vessels from Georgia and elsewhere and were found in a building whose context is suggestive of a small shrine. Their palynological spectra match those of present-day wine and wine containers of other periods. One of them was intact, with only a small access hole; consequently, its palynological spectrum can be utilized as a standard for determining the presence of wine in other archaeological vessels. Palynological analyses from different contexts of the Aradetis Orgora settlement and its cemetery (Doghlauri) yielded other significant results regarding the practice of viticulture and the cultural relevance of wine during the Kura-Araxes period.  相似文献   
23.
How did traditional farming transform the natural environment in the Hawaiian Islands? This question is one that has largely been addressed for rainfed farming of crops like sweet potato (Ipomoea batatas), but evidence is lacking for irrigated farming of the critical staple crop taro (Colocasia esculenta). We describe the results of soil nutrient and sedimentological analyses of deeply-stratified pondfield deposits representing a 600-year-long record of irrigated taro farming in the North Kohala District, Hawai‘i Island. Soil is categorized by particle size to determine modes of transport and deposition, and concurrent soil nutrient analyses were conducted to infer shifts in the source of sediments and changes associated with taro harvesting. The advent of farming is clearly detectable in sedimentology, the presence of charcoal found within sediments, and soil chemistry. However, diminished nutrient concentrations can be attributed largely to deposition of a mixture of upstream sediments. Overall, there is no clear evidence for nutrient draw-down by taro harvesting, but we cannot yet rule it out as a factor. This study demonstrates the inherent difficulty of correlating changes in soil nutrients evident in irrigated pondfields with the long term history of soil nutrient cycling.  相似文献   
24.
The aim of this work was to detect imprints on soil properties from former Islamic land use (9th to 11th century) using a multi-method, soil-chemical approach. Four soil profiles (with buried horizons) found in the vicinities of former Islamic settlements in Sicily were analysed for phosphorus (total, organic and inorganic), nitrogen (total, NO3 and NH4+), carbon compounds (δ13C, lipids, polycyclic aromatic hydrocarbons (PAH) and functional groups), physical and chemical C-fractions and the state of soil weathering. Two soil profiles contained ceramic sherds from the Islamic period. Inorganic nitrogen forms, phosphorous and the PAH content indicated strong impacts from traditional agriculture and/or burning. Radiocarbon dating of soil organic carbon (SOC) fractions from buried horizons showed that distinct changes must have occurred during the Islamic epoch. The isotopic composition of SOC indicated that land use was probably different in earlier times. C4 plant cultivation was expected but surprisingly lipid analyses did not confirm this. A high amount of aliphates and low C/N ratio indicated a good, long-term SOC stabilisation under the native conditions combined with Islamic land use. The irrigation of the soils probably increased the production of weakly-crystalline Fe forms that helped to stabilise SOC.  相似文献   
25.
A source-to-sink multi-proxy approach has been performed within Lake Paladru (492 m a.s.l., French Prealps) catchment and a 6-m long sediment sequence retrieved from the central lacustrine basin. The combination of minerogenic signal, specific organic markers of autochthonous and allochthonous supply and archaeological data allows the reconstruction of a continuous record of past human disturbances. Over the last 10,000 years, the lacustrine sedimentation was dominated by autochthonous carbonates and the watershed was mostly forest-covered. However, seven phases of higher accumulation rate, soil erosion, algal productivity and landscape disturbances have been identified and dated from 8400 to 7900, 6000 to 4800, 4500 to 3200, 2700 to 2050 cal BP as well as AD 350–850, AD 1250–1850 and after AD 1970. Before 5200 cal BP, soil erosion is interpreted as resulting from climatic deterioration phases towards cooler and wetter conditions. During the Mid-Late Holocene period, erosion fluxes and landscape disturbances are always associated with prehistorical and historical human activities and amplified by climatic oscillations. Such changes in human land-used led to increasing minerogenic supply and nutrients loading that affected lacustrine trophic levels, especially during the last 1600 years. In addition, organic and molecular markers document previously unknown human settlements around Lake Paladru during the Bronze and the Iron Ages.  相似文献   
26.
An approach devoted to quickly assess the thickness of soft sedimentary cover in areas of unknown subsurface morphology is applied in this study. In particular, soil thickness (h) is derived by combining estimates of the resonance frequency (f r ) relative to soft sediments with the local shear-wave velocity (Vs) profile. For this purpose, (f r ) values are assessed from horizontal to vertical (H/V) spectral ratios of seismic noise recordings and the (V s ) profile is obtained by considering information from shallow seismic surveys. Results obtained for a Quaternary sedimentary basin in Southern Italy are discussed. Since in the investigated area only weak independent constraints are available, special emphasis is given to the assessment of uncertainties involved in this estimate of soil thickness.  相似文献   
27.
A simple and general method based on well-known random vibration theory is used to compute spectral attenuation relations at soft sites based on existing spectral attenuation relations at rock sites. The method consists of: (1) computation, for given magnitude and distance, of the expected Fourier amplitude spectrum associated with the median rock response spectrum computed with the attenuation relation; (2) inclusion of site effects characterized by a frequency-dependent, linear, or nonlinear transfer function; and (3) computation of the response spectrum at the soft site.  相似文献   
28.
A system identification framework is proposed to investigate the nonlinear dynamic response of massive earth dams using the seismic motion recorded by a sparse array of accelerometers. The framework includes a methodical step of nonparametric analyses to characterize the involved loading conditions and response mechanisms. This nonparametric step provides essential information to reduce the indeterminacy of the associated parametric identificatin problem and ensure a proper model selection, calibration, and validation. The proposed framework was applied to the Long Valley earth dam (California) and benchmarked using records of a series of 1980 earthquakes. This article presents the conducted correlation, spectral motion reconstruction, and nonparametric stress-strain analyses. These analyses revealed a complex three-dimensional dynamic response marked by non uniform boundary conditions and a shear stress-strain behavior slightly less nonlinear than what was observed in triaxial tests of soil samples taken from the dam core.  相似文献   
29.
Soil was modelled with linearly elastic three-dimensional finite elements. Lateral spring stiffness was calculated from FE results. Spring stiffness is shown varying linearly with shaft diameter. It is also found that spring stiffness is inversely proportional to powers (less than unity) of pile flexural rigidity. Scaling factors for shaft diameter and pile flexural rigidity are introduced. Basic stiffness of lateral spring is studied considering both full vertical slippage and zero slippage between the soil and the pile. Relevant relationships for stiffness are proposed. Some applications are suggested.  相似文献   
30.
The soil which has developed at any given location is considered to be the result of five interacting factors: parent material, time, climate, topography and biotic factors. This paper discusses the role of these factors in the development of Scottish soils, which fall into three broad categories: leached soils, gley soils and organic soils. The intention is to provide a context for the case studies that follow in later papers.  相似文献   
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