Soils of Agricultural Terraces with Retaining Walls in the Mountains of Dagestan

Science.gov (United States)

Borisov, A. V.; Korobov, D. S.; Idrisov, I. A.; Kalinin, P. I.

2018-01-01

Soil-archeological studies of agricultural terraces with retaining walls in the area of construction of the Gotsatlinskaya Hydroelectric Power Station in Khunzakh district of the Republic of Dagestan have been performed. The morphogenetic and chemical properties of the anthropogenic soils (Anthrosols) in different parts of the terrace complex are analyzed. It is argued that slope terracing in the mountains ensures the development of thicker soil profiles with pronounced genetic horizons. The soils of agricultural terraces store important information of the paleoenvironmental history and land use. A characteristic feature of the Anthrosols of agricultural terraces is a relatively even distribution of gravelly material of up to 5 cm in diameter in the plow layer. The soils of terraces are characterized by the high variability in their properties within the entire terrace complex and within the particular terraces.

Cost-benefit of bench terraces, a case study in Peru

NARCIS (Netherlands)

Posthumus, H.; Graaff, de J.

2005-01-01

Soil and water conservation measures like bench terraces can reduce erosion in highland crop production. A cost-benefit analysis for 11 cases of bench terraces was undertaken on the basis of both measured data and data obtained from farmers. It showed that the profitability of bench terraces was

Effects of terracing on soil and water conservation in China: A meta-analysis

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Chen, Die; Wei, Wei

2017-04-01

Terracing has long been considered a powerful strategy for soil and water conservation. However, the efficiency is limited by many factors, such as climate, soil properties, topography, land use, population and socioeconomic status. The aim of this critical review was to discuss the effects of terracing on soil and water conservation in China, using a systematic approach to select peer-reviewed articles published in English and Chinese. 46 individual studies were analyzed, involving six terracing structures (level terraces, slope-separated terraces, slope terraces, reverse-slope terraces, fanya juu terraces and half-moon terraces), a wide geographical range (Northeastern China, Southeastern hilly areas, Southwestern mountain areas and Northwestern-central China), and six land use types (forest, crop trees, cropland, shrub land, grassland and bare land) as well as a series of slope gradients ranging from 3° to 35°. Statistical meta-analysis with runoff for 593 observations and sediment for 636 observations confirmed that terracing had a significant effect on water erosion control. In terms of different terrace structures, runoff and sediment reduction were uppermost on slope-separated terraces. Land use in terraces also played a crucial role in the efficiency of conservation, and tree crops and forest were detected as the most powerful land covers in soil and water conservation due to large aboveground biomass and strong root systems below the ground, which directly reduces the pressure of terraces on rainwater redistribution. In addition, a significant positive correlation between slope gradients (3° 15° and 16° 35°) and terracing efficiency on soil and water conservation was observed. This study revealed the effectiveness and variation of terracing on water erosion control on the national scale, which can serve as a scientific basis to land managers and decision-makers.

Nature and regulation: Management of vineyards and orchards on terraces

Directory of Open Access Journals (Sweden)

Andreja Škvarč

2006-01-01

Full Text Available The article deals with vineyards and terrace building as the best method of managing agricultural land on the steep slopes of the Primorska region. Data was gathered about the share of terraced vineyards and shares of vineyards according to inclination classes. We explained what the term renewal of permanent plantation implies and especially vineyards, as well as its scope. Reasons for terracing are elaborated, as well as difficulties that are coupled with such land management. We also point out the consequences of abandonment of vineyards on terraces.

Multiple paths to straths: A review and reassessment of terrace genesis

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Schanz, Sarah A.; Montgomery, David R.; Collins, Brian D.; Duvall, Alison R.

2018-07-01

Strath terraces, an important tool in tectonic geomorphology, have been attributed to climatic, tectonic, volcanic, and human activity, yet the pathways connecting external forcings to the channel response leading to terrace formation are highly variable and complex. To better understand variability and controls on the pathways between forcing and terrace formation, we created a comprehensive database of 421 strath terraces from peer-reviewed literature and noted the strath age and rock type, the ascribed forcing (climate, tectonics, volcanoes, or humans) or whether the cause was unascribed, and the pathway between forcing and strath incision or planation. Study authors identify climate, tectonics, volcanoes, and humans as the forcing for 232 (55%), 20 (5%), 8 (2%), and 5 (1%) strath terraces in our compilation respectively. A forcing was not identified for the remaining 156 (37%) terraces. Strath terraces were dated using 14 different methods: 71% of terraces in our database are dated using methods, such as radiocarbon and optically stimulated luminescence, that date planation and give a maximum age of incision; 16% of terraces are dated with methods that give a minimum age of incision; and 14% use a variety of methods for which a generalization about incision age cannot be made. That the majority of terrace studies use planation ages to understand terrace formation highlights the necessity of knowing the relative timescales of incisional and planation phases, which has so far been quantified in only a handful of studies. In general, rivers in arid regions plane straths in interglacial periods when discharge and sediment transport capacity increase, whereas temperate rivers plane in glacial or interglacial periods when sediment supply increases. Heterogeneities in rock strength between watersheds further control how sediment is produced and when straths are planed. Globally, these regional and watershed controls result in strath planation and incision during all

The Meaning of Terrace as Social Interaction Place in Vertical Kampung

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Sihombing, Antony; Gumay Poetri, Nurul

2018-01-01

The pros and cons of vertical housing development in Jakarta make me intend to raise the issue of the vertical kampung. In the kampung, there are social spaces where people interact to create a culture of rukun and gotong-royong. It is the terrace which become a container of social interaction. The purpose of this study is to reveal the meaning of the terrace in social interaction in the vertical kampung and its influence when the terrace room is not presented in the vertical kampung. The lost meaning of kampung when terrace is not presented in vertical kampung can be known through cognitive maps. Cognitive maps are the methodologies used to gain a human perception or view of life experiences in a particular place. This study involved several families in West Jatinegara Rusunawa to find out how people looked at the terrace in their life while in Kampung Pulo. Based on the cognitive maps method that has been done by the respondents, the terrace referred to by the villagers is an open space where people can see and interact with each other. Social space in the form of terraces which is needed by the kampung dweller, in fact is not a terrace house which is used as a place to receive guests and as a barrier between the fence and the body of the house.

Economic and social activities on ancient Cypriot terraced landscapes.

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Ridder, Elizabeth; Galletti, Christopher S; Fall, Patricia L; Falconer, Steven E

2017-11-01

We investigate ancient agricultural terraces and their associated social and economic activities across the site complex consisting of the village at Politiko-Troullia and its more extensive associated taskscape. Surface artifact distributions mapped over 12 ha are integrated with evidence excavated from this Bronze Age settlement in central Cyprus. Contrary to expectations, artifact densities do not diminish with distance from the village architecture. In particular, concentrations of Prehistoric Bronze Age ceramics and ground stone artifacts are most pronounced on nearby terraced hillsides. These terraces were not utilized for domestic structures, but for extensive processing of agricultural crops and copper ore. Bronze Age excavated plant remains indicate cultivation of olives, grapes and figs, with wood resources dominated by olive and pine. Larger, non-portable ground stones and gaming stones are associated with communal social and economic activities in open courtyard settings in Politiko-Troullia. This category of ground stone also is particularly common on the terraced hillsides around Troullia, suggesting that similar behaviors occurred beyond village structures. The terraced landscape of Politiko-Troullia exemplifies a multi-faceted taskscape with a range of agricultural, metallurgical and social activities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Soil chemistry and mineralogy of the Santa Cruz coastal terraces

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Pinney, Colin; Aniku, Jacob; Burke, Raymond; Harden, Jennifer; Singer, Michael; Munster, Jennie

2002-01-01

Marine terraces in the central coast of California provide an opportunity to study a soil chronosequence in which similar materials (beach deposits) have been weathered under similar slope, climatic, and vegetation conditions during the Quaternary. The terraces between Santa Cruz and Año Nuevo, California, have been studied for decades and are thought to be one of the best example of marine terraces in California {Lawson (1893), Wilson (1907); Branner and others (1909), Rode (1930) Page and Holmes (1945), Alexander (1953), Bradley (1956, 1957, 1958, and 1965), Bradley and Addicott (1968), Clark (1966 and 1970), Jahns and Hamilton (1971), Lajoie and others (1972), Bradley and Griggs (1976). Hanks and others (1986), Aniku (1986), Fine and others (1988), Anderson (1990 and 1994), and Rosenbloom and Anderson (1994).} Here we report morphological, chemical, physical, and mineralogical data for the soils that were formed in deposits on the Santa Cruz marine terraces in order to examine soil characteristics as a function of increasing terrace age.

High-Resolution Geologic Mapping of Martian Terraced Fan Deposits

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Wolak, J. M.; Patterson, A. B.; Smith, S. D.; Robbins, N. N.

2018-06-01

This abstract documents our initial progress (year 1) mapping terraced fan features on Mars. Our objective is to investigate the role of fluids during fan formation and produce the first high-resolution geologic map (1:18k) of a terraced fan.

Study on weathering index for improving the reliability of terrace correlation and chronology. Part 2. Understanding weathering condition of terrace gravel and induction of application requirement for correlation index

International Nuclear Information System (INIS)

Hamada, Takaomi

2012-01-01

Geomorphographic survey of fluvial terraces, geological exploration, borehole drilling and investigation, and analysis of weathering condition of terrace gravels were carried out in Chuetsu area, Niigata prefecture, where a great deal of geomorphostratigraphic and tephrostratigraphic data are available. The results of these surveys and investigations indicate that weathering degree of terrace gravels can be considered as an index of the terrace age, and also provide points to remember for sampling and method of sampling and observation. The effective porosity and the thickness of weathering rind of gravels, which are indexes for weathering degree evaluation, in boring core, increase above the depth of about 5m from the top of the hole. Weathering doesn't reach the deep portion, therefore, investigation and evaluation for the weathering degree of terrace gravels must be carried out on the upper portion. Weathering rind thickness and effective porosity of the gravels are dispersive. Dispersion of the weathering rind thickness can be reduced by confining to andesite, and dispersion of the effective porosity can be reduced by limiting range of gravel size. Reducing dispersion, increase trend with age becomes clear in change of the weathering rind thickness and the effective porosity in many of the studied area. It shows that weathering rind thickness and effective porosity are effective for terrace correlation. Dispersion of data in an outcrop isn't small, but data from neighboring terraces with the same age are not different each other. It indicates that weathering rind thickness and effective porosity can be quantitative indexes for terrace age evaluation. In area where weathering rind is effective for terrace correlation, the rate of the weathering rind formation of andesite gravels is about 0.04mm/1000 years. Therefore, MIS6 terraces and MIS8 terraces can be distinguished each other by means of thickness of the weathering rind. This formation rate falls inside the

Time scale for degradation and erosion of archaeological terraces in the Judea Mountains, Israel

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Porat, Naomi; Elinson, Rotem; Ben Dor, Eyal; Avni, Yoav; Gadot, Yuval

2017-04-01

The fate of mountain bench terraces which have been abandoned in ancient times is puzzling. On the one hand recently abandoned terraces undergo rapid degradation by walls crumbling, leading to soil being washed by rain water out of breaches in the walls, suggesting that within a short time all soil would be washed down-slope. On the other hand slopes with degraded terraces appear to still retain much soil even though only faint remains of the terraces exist. Moreover, if soil is rapidly eroded down-slope when terraces are no longer maintained, where do subsequent terrace builders find the soil to fill behind the stone walls? These questions were addressed as part of a larger study on the chronology of terraces in the Judea Mountains, Israel. Previous OSL dating of terrace soils in the region showed that the majority of the maintained terraces were constructed during the past 700 years, and only occasionally older ages were obtained for the soil at the very base of these terraces. Concerns were raised that soil erosion caused earlier events of terrace construction to disappear. To check if terraces and soils indeed erode entirely and how long this might take, we selected a relatively smooth hill slope showing small patches of limestone bedrock as well as remains of highly degraded sets of terraces. Three pits were excavated in soils within three different terrace remains down to bedrock, some to a depth of 2 m, and samples for OSL dating were collected from the exposed soil sections. In all three pits the lowermost samples gave ages of 3000-4500 years before the present, possibly the natural soils before any human intervention. However samples from a depth of 35-45 cm gave ages of 350-200 years, providing the last time the soil at that depth was exposed to sunlight. This suggests that the terraces were abandoned in the past 200 years or so and since then degraded. However the thick soil present on most of the slope suggests that after the first stage of rapid

Soil slips and debris flows on terraced slopes

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Crosta, G. B.; Dal Negro, P.; Frattini, P.

Terraces cover large areas along the flanks of many alpine and prealpine valleys. Soil slips and soil slips-debris flows are recurrent phenomena along terraced slopes. These landslides cause damages to people, settlements and cultivations. This study investigates the processes related to the triggering of soil slip-debris flows in these settings, analysing those occurred in Valtellina (Central Alps, Italy) on November 2000 after heavy prolonged rainfalls. 260 landslides have been recognised, mostly along the northern valley flank. About 200 soil slips and slumps occurred in terraced areas and a third of them evolved into debris flows. Field work allowed to recognise the settings at soil slip-debris flow source areas. Landslides affected up to 2.5 m of glacial, fluvioglacial and anthropically reworked deposits overlying metamorphic basement. Laboratory and in situ tests allowed to characterise the geotechnical and hydraulic properties of the terrains involved in the initial failure. Several stratigraphic and hydrogeologic factors have been individuated as significant in determining instabilities on terraced slopes. They are the vertical changes of physical soil properties, the presence of buried hollows where groundwater convergence occurs, the rising up of perched groundwater tables, the overflow and lateral infiltration from superficial drainage network, the runoff concentration by means of pathways and the insufficient drainage of retaining walls.

Deposition of eroded soil on terraced croplands in Minchet catchment, Ethiopian Highlands

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Alemtsehay Subhatu

2017-09-01

Full Text Available In the Ethiopian Highlands, soil and water conservation practices are of utmost importance to conserve eroded soil and combat soil loss. This study provides detailed results on on-site sediment deposition and net soil loss in terraced croplands in a catchment in the sub-humid Ethiopian Highlands. Sediment deposition was measured on horse bean and maize fields during the crop growing seasons of 2014 and 2015. Measurements took place on observation plots on terraced cropland with varying spacing between terraces and varying slope gradients. Net soil loss, in this case the amount leaving the terraced cropland, was calculated by modelling the Universal Soil Loss Equation (USLE for the whole observation field and subtracting the measured sediment deposition. The study result showed about 8–11 t ha−1 sediment was deposited in the deposition zone of the terraced cropland, with greater sediment deposition on terraces with narrow spacing and steeper slope gradients. Sediment deposition was highest in July and August, and relatively low in September. Annual soil loss ranged from 32 to 37 t ha−1 in the terraced cropland of the study area. From the total soil loss in the crop growing season, about 54–74% sediment was deposited on the deposition zone of terraced crop fields. Implementation of soil and water conservation with narrow spacing, especially on the steep slopes of the sub-humid Ethiopian Highlands or other similar area, are thus highly recommended as they enable conservation of the eroded soil in the cropland.

Research on Remote Sensing recognition features of Yuan Yang Terraces in Yunnan Province (China)

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Xiang, Jie; Chen, Jianping; Lai, ZiLi; Yang, Wei

2016-04-01

Yuan Yang terraces is one of the most famous terraces in China, and it was successfully listed in the world heritage list at the 37th world heritage convention. On the one hand, Yuan Yang terraces retain more soil and water, to reduce both hydrological connectivity and erosion, and to support irrigation. On the other hand, It has the important tourism value, bring the huge revenue to local residents. In order to protect and make use of Yuan Yang terraces better, This study analyzed the spatial distribution and spectral characteristics of terraces:(1) Through visual interpretation, the study recognized the terraces based on the spatial adjusted remote sensing image (2010 Geoeye-1 with resolution of 1m/pix), and extracted topographic feature (elevation, slope, aspect, etc.) based on the digital elevation model with resolution of 20m/pix. The terraces cover a total area of about 11.58Km2, accounted for 24.4% of the whole study area. The terraces appear at range from 1400m to 1800m in elevation, 10°to 20°in slope, northwest to northeast in aspect; (2) Using the method of weight of evidence, this study assessed the importance of different topographic feature. The results show that the sort of importance: elevation>slope>aspect; (3) The study counted the Normalized Difference Vegetation Index (NDVI) changes of terraces throughout the year, based on the landsat-5 image with resolution of 30m/pix. The results show that the changes of terraces' NDVI are bigger than other stuff (e.g. forest, road, house, etc.). Those work made a good preparations for establishing the dynamic remote sensing monitoring system of Yuan Yang terraces.

Modelling the impact of regional uplift and local tectonics on fluvial terrace preservation.

NARCIS (Netherlands)

Viveen, W.; Schoorl, J.M.; Veldkamp, A.; Balen, van R.T.

2014-01-01

A terrace formation model (TERRACE) combined with a longitudinal river profile model (FLUVER) was used to simulate fluvial terrace formation and preservation in the northwest Iberian lower Miño River basin under the influence of three tectonic conditions; namely regional vertical uplift, local basin

Dating of river terraces along Lefthand Creek, western High Plains, Colorado, reveals punctuated incision

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Foster, Melissa A.; Anderson, Robert S.; Gray, Harrison J.; Mahan, Shannon A.

2017-10-01

The response of erosional landscapes to Quaternary climate oscillations is recorded in fluvial terraces whose quantitative interpretation requires numerical ages. We investigate gravel-capped strath terraces along the western edge of Colorado's High Plains to constrain the incision history of this shale-dominated landscape. We use 10Be and 26Al cosmogenic radionuclides (CRNs), optically stimulated luminescence (OSL), and thermally transferred OSL (TT-OSL) to date three strath terraces, all beveled in shale bedrock and then deposited upon by Lefthand Creek, which drains the crystalline core of the Front Range. Our study reveals: (i) a long history (hundreds of thousands of years) of fluvial occupation of the second highest terrace, T2 (Table Mountain), with fluvial abandonment at 92 ± 3 ka; (ii) a brief occupation of a narrow and spatially confined terrace, T3, at 98 ± 7 ka; and (iii) a 10-25 thousand year period of cutting and fluvial occupation of a lower terrace, T4, marked by the deposition of a lower alluvial unit between 59 and 68 ka, followed by deposition of an upper alluvial package at 40 ± 3 ka. In conjunction with other recent CRN studies of strath terraces along the Colorado Front Range (Riihimaki et al., 2006; Dühnforth et al., 2012), our data reveal that long periods of lateral planation and fluvial occupation of strath terraces, sometimes lasting several glacial-interglacial cycles, are punctuated by brief episodes of rapid vertical bedrock incision. These data call into question what a singular terrace age represents, as the strath may be cut at one time (its cutting-age) and the terrace surface may be abandoned at a much later time (its abandonment age), and challenge models of strath terraces that appeal to simple pacing by the glacial-interglacial cycles.

Effects of marsh pond terracing on coastal wintering waterbirds before and after Hurricane Rita.

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O'Connell, Jessica L; Nyman, John A

2011-11-01

From February to March 2005-2006, we surveyed wintering waterbirds to test effects of terracing on coastal pond use before and after Hurricane Rita. Marsh terracing is intended to slow coastal marsh loss in the Chenier Plain by slowing marsh erosion and encouraging vegetation expansion. Terraces also increase marsh edge in ponds, possibly benefiting waterbirds. We monitored paired terraced and unterraced ponds in three sites within southwestern Louisiana's Chenier Plain. Waterbirds were 75% more numerous in terraced than unterraced ponds. Waterbird richness was similar among ponds when corrected for number of individuals, suggesting terracing increased bird density but did not provide habitat unique from unterraced ponds. Birds were 93% more numerous following Hurricane Rita, mostly due to an influx of migrating waterfowl. Year round residents were similar in number before and after Hurricane Rita. Resident richness did not differ among years after correcting for number of observed individuals. Wading and dabbling foragers were more abundant in terraced ponds and these two guilds represented 74% of birds observed. We detected no difference among ponds for other guilds, i.e., probing, aerial, and diving foragers. Increasing proportion of mash edge increased bird density disproportionately: On average ponds with 10% edge had 6 birds observed and ponds with 30% edge had 16 birds observed. Terraces increased habitat interspersion and were an effective tool for increasing numbers of wintering waterfowl and wading birds. The extent to which terraces were sustainable following hurricane forces is unknown.

Effects of Marsh Pond Terracing on Coastal Wintering Waterbirds Before and After Hurricane Rita

Science.gov (United States)

O'Connell, Jessica L.; Nyman, John A.

2011-11-01

From February to March 2005-2006, we surveyed wintering waterbirds to test effects of terracing on coastal pond use before and after Hurricane Rita. Marsh terracing is intended to slow coastal marsh loss in the Chenier Plain by slowing marsh erosion and encouraging vegetation expansion. Terraces also increase marsh edge in ponds, possibly benefiting waterbirds. We monitored paired terraced and unterraced ponds in three sites within southwestern Louisiana's Chenier Plain. Waterbirds were 75% more numerous in terraced than unterraced ponds. Waterbird richness was similar among ponds when corrected for number of individuals, suggesting terracing increased bird density but did not provide habitat unique from unterraced ponds. Birds were 93% more numerous following Hurricane Rita, mostly due to an influx of migrating waterfowl. Year round residents were similar in number before and after Hurricane Rita. Resident richness did not differ among years after correcting for number of observed individuals. Wading and dabbling foragers were more abundant in terraced ponds and these two guilds represented 74% of birds observed. We detected no difference among ponds for other guilds, i.e., probing, aerial, and diving foragers. Increasing proportion of mash edge increased bird density disproportionately: On average ponds with 10% edge had 6 birds observed and ponds with 30% edge had 16 birds observed. Terraces increased habitat interspersion and were an effective tool for increasing numbers of wintering waterfowl and wading birds. The extent to which terraces were sustainable following hurricane forces is unknown.

Agronomic Challenges and Opportunities for Smallholder Terrace Agriculture in Developing Countries.

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Chapagain, Tejendra; Raizada, Manish N

2017-01-01

Improving land productivity is essential to meet increasing food and forage demands in hillside and mountain communities. Tens of millions of smallholder terrace farmers in Asia, Africa, and Latin America who earn $1-2 per day do not have access to peer-reviewed knowledge of best agronomic practices, though they have considerable traditional ecological knowledge. Terrace farmers also lack access to affordable farm tools and inputs required to increase crop yields. The objectives of this review are to highlight the agronomic challenges of terrace farming, and offer innovative, low-cost solutions to intensify terrace agriculture while improving local livelihoods. The article focuses on smallholder farmers in developing nations, with particular reference to Nepal. The challenges of terrace agriculture in these regions include lack of quality land area for agriculture, erosion and loss of soil fertility, low yield, poor access to agricultural inputs and services, lack of mechanization, labor shortages, poverty, and illiteracy. Agronomic strategies that could help address these concerns include intensification of terraces using agro-ecological approaches along with introduction of light-weight, low-cost, and purchasable tools and affordable inputs that enhance productivity and reduce female drudgery. To package, deliver, and share these technologies with remote hillside communities, effective scaling up models are required. One opportunity to enable distribution of these products could be to "piggy-back" onto pre-existing snackfood/cigarette/alcohol distribution networks that are prevalent even in the most remote mountainous regions of the world. Such strategies, practices, and tools could be supported by formalized government policies dedicated to the well-being of terrace farmers and ecosystems, to maintain resiliency at a time of alarming climate change. We hope this review will inform governments, non-governmental organizations, and the private sector to draw

The physical model of a terraced plot: first results

Science.gov (United States)

Perlotto, Chiara; D'Agostino, Vincenzo; Buzzanca, Giacomo

2017-04-01

Terrace building have been expanded in the 19th century because of the increased demographic pressure and the need to crop additional areas at steeper slopes. Terraces are also important to regulate the hydrological behavior of the hillslope. Few studies are available in literature on rainfall-runoff processes and flood risk mitigation in terraced areas. Bench terraces, reducing the terrain slope and the length of the overland flow, quantitatively control the runoff flow velocity, facilitating the drainage and thus leading to a reduction of soil erosion. The study of the hydrologic-hydraulic function of terraced slopes is essential in order to evaluate their possible use to cooperate for flood-risk mitigation also preserving the landscape value. This research aims to better focus the times of the hydrological response, which are determined by a hillslope plot bounded by a dry-stone wall, considering both the overland flow and the groundwater. A physical model, characterized by a quasi-real scale, has been built to reproduce the behavior of a 3% outward sloped terrace at bare soil condition. The model consists of a steel metal box (1 m large, 3.3 m long, 2 m high) containing the hillslope terrain. The terrain is equipped with two piezometers, 9 TDR sensors measuring the volumetric water content, a surface spillway at the head releasing the steady discharge under test, a scale at the wall base to measure the outflowing discharge. The experiments deal with different initial moisture condition (non-saturated and saturated), and discharges of 19.5, 12.0 and 5.0 l/min. Each experiment has been replicated, conducting a total number of 12 tests. The volumetric water content analysis produced by the 9 TDR sensors was able to provide a quite satisfactory representation of the soil moisture during the runs. Then, different lag times at the outlet since the inflow initiation were measured both for runoff and groundwater. Moreover, the time of depletion and the piezometer

Effectiveness of the GAEC standard of cross compliance retain terraces on soil erosion control

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Paolo Bazzoffi

2011-08-01

Full Text Available The GAEC standard retain terraces of cross compliance prohibits farmers the elimination of existing terraces, with the aim to ensure the protection of soil from erosion. In the Italian literature there are not field studies to quantify the effects of the elimination or degradation of terraces on soil erosion. Therefore, the modeling approach was chosen and applied in a scenario analysis to evaluate increasing levels of degradation of stone wall terraces. The study was conducted on two sample areas: Lamole (700.8 ha, Tuscany and Costaviola (764.73 ha, Calabria with contrasting landscapes. The Universal Soil Loss Equation model (USLE was applied in the comparative assessment of the soil erosion risk (Mg . ha-1 . yr-1, by simulating five increasing intensity of terrace degradation, respectively: conserved partially damaged, very damaged, partially removed, removed, each of which corresponding to different values of the indexes of verification in case of infringement to GAEC standard provided for by the AGEA rules which have come into force since December 2009 (Agency for Agricultural Payments. To growing intensity of degradation, a progressive loss of efficacy of terraces was attributed by increasing the values of the LS factor (length and slope of USLE in relation with the local modification of the length and steepness of the slope between adjacent terraces. Basically, it was simulated the gradual return to the natural morphology of the slope. The results of the analysis showed a significant increase in erosion in relationship with increasing degradation of terraces. Furthermore, it is possible to conclude that the GAEC standard retain terraces is very effective with regard to the primary objective of reducing erosion. A further statistical analysis was performed to test the protective value of terraces against soil erosion in areas where agriculture was abandoned. The analysis was carried out by comparing the specific risk of erosion (Mg . ha-1

On the polychroism of river terraces in mountain areas

International Nuclear Information System (INIS)

Pshenin, G.N.; Serebryanyj, L.R.

1981-01-01

Using the method of 14 C isotope dating the age of alluvial deposits of river terraces in mountain areas in Fergana is studied. It is shown that the age of the deposits varies from 16 to 10 thousand years. Their formation as dynamically independent, self-developing systems is pointed out. The role of endo- and exogenous factors in the process of terrace-formation evidently comes to the trigger effect [ru

Influence of Terraced area DEM Resolution on RUSLE LS Factor

Science.gov (United States)

Zhang, Hongming; Baartman, Jantiene E. M.; Yang, Xiaomei; Gai, Lingtong; Geissen, Viollette

2017-04-01

Topography has a large impact on the erosion of soil by water. Slope steepness and slope length are combined (the LS factor) in the universal soil-loss equation (USLE) and its revised version (RUSLE) for predicting soil erosion. The LS factor is usually extracted from a digital elevation model (DEM). The grid size of the DEM will thus influence the LS factor and the subsequent calculation of soil loss. Terracing is considered as a support practice factor (P) in the USLE/RUSLE equations, which is multiplied with the other USLE/RUSLE factors. However, as terraces change the slope length and steepness, they also affect the LS factor. The effect of DEM grid size on the LS factor has not been investigated for a terraced area. We obtained a high-resolution DEM by unmanned aerial vehicles (UAVs) photogrammetry, from which the slope steepness, slope length, and LS factor were extracted. The changes in these parameters at various DEM resolutions were then analysed. The DEM produced detailed LS-factor maps, particularly for low LS factors. High (small valleys, gullies, and terrace ridges) and low (flats and terrace fields) spatial frequencies were both sensitive to changes in resolution, so the areas of higher and lower slope steepness both decreased with increasing grid size. Average slope steepness decreased and average slope length increased with grid size. Slope length, however, had a larger effect than slope steepness on the LS factor as the grid size varied. The LS factor increased when the grid size increased from 0.5 to 30-m and increased significantly at grid sizes >5-m. The LS factor was increasingly overestimated as grid size decreased. The LS factor decreased from grid sizes of 30 to 100-m, because the details of the terraced terrain were gradually lost, but the factor was still overestimated.

Desert agricultural terrace systems at EBA Jawa (Jordan) - Layout, water availability and efficiency

Science.gov (United States)

Meister, Julia; Krause, Jan; Müller-Neuhof, Bernd; Portillo, Marta; Reimann, Tony; Schütt, Brigitta

2016-04-01

Located in the arid basalt desert of northeastern Jordan, the Early Bronze Age (EBA) settlement of Jawa is by far the largest and best preserved archaeological EBA site in the region. Recent surveys in the close vicinity revealed well-preserved remains of three abandoned agricultural terrace systems. In the presented study these archaeological features are documented by detailed mapping and the analysis of the sediment records in a multi-proxy approach. To study the chronology of the terrace systems optically stimulated luminescence (OSL) is used. In order to evaluate the efficiency of the water management techniques and its impact on harvest yields, a crop simulation model (CropSyst) under today's climatic conditions is applied, simulating crop yields with and without (runoff) irrigation. In order to do so, a runoff time series for each agricultural terrace system and its catchment is generated, applying the SCS runoff curve number method (CN) based on rainfall and soil data. Covering a total area of 38 ha, irrigated terrace agriculture was practiced on slopes, small plateaus, and valleys in the close vicinity of Jawa. Floodwater from nearby wadis or runoff from adjacent slopes was collected and diverted via surface canals. The terraced fields were arranged in cascades, allowing effective water exploitation through a system of risers, canals and spillways. The examined terrace profiles show similar stratigraphic sequences of mixed unstratified fine sediments that are composed of small-scale relocated sediments with local origin. The accumulation of these fines is associated with the construction of agricultural terraces, forcing infiltration and storage of the water within the terraces. Two OSL ages of terrace fills indicate that the construction of these terrace systems started as early as 5300 ± 300 a, which fits well to the beginning of the occupation phase of Jawa at around 3.500 calBC, thus making them to the oldest examples of its kind in the Middle East

THE INFLUENCE OF PRIVACY REGULATION ON URBAN MALAY FAMILIES LIVING IN TERRACE HOUSING

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Ahmad Ahmad Hashim

2008-07-01

Full Text Available This paper reports on behavioral norms and territoriality as part of behavioral and environmental mechanisms used to regulate privacy among urban Malay families living in terrace housing. In-depth interview was employed involving 11 case studies of Malay families living in three-bedroom two-storey terrace housings in the urban areas. Findings indicate that while most of the behavioral norms employed to regulate privacy are consistent with Malay cultural norms and religious belief, there are a few which are not consistent due to the constraint of terrace housing. Defined territory and the need to respect the neighbors’ privacy are found to indirectly affect community intimacy among Malay families living in terrace housings.

Study on thermoluminescence dating for Nideping terrace of Dongchuan, Yunnan province

International Nuclear Information System (INIS)

Zhang Bin; Wei Mingjian; Liu Chao; Zhang Yongdong; Zhou Rui; Liu Junxin; Liu Tiantian; Zhao Qiuyue; Song Bo

2013-01-01

The sequence of geological age on Nideping terrace in Dongchuan, Yunnan Province was established by thermoluminescence. The result shows that the age of the terrace is 9.3-57.1 ka. The vertical age of ancient debris flow terraces was established, and the time structure of Nideping mud was received. The age data was provided for the restoration ancient environment of the debris flow. It is shown that the debris flow deposits have discontinuities through age data and exist age inversion. The radioactive elements such as uranium, thorium, potassium may be leaching deposition affected by the presence of local rainfall and the annual dose rate increases with depth. (authors)

Designing terraces for the rainfed farming region in Iraq using the RUSLE and hydraulic principles

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Mohammad H. Hussein

2016-03-01

Full Text Available The rainfed region in Iraq comprises an area of more than 5 million ha of forest, grazing and farmland areas. Except the plains, the region suffers from moderate to severe water erosion due mainly to overgrazing and land mismanagement. Due to population growth and the shortage in water resources, an expansion in land used for agriculture in the region is expected. Terracing is an option when utilizing sloping land for agricultural production. A terrace design criterion was developed for the region in which terrace spacing was determined using the Revised Universal Soil Loss Equation (RUSLE; terrace channel specifications were determined using conventional hydraulic computations. Analyses showed that terracing is feasible on rolling and hilly sloping land in the high rainfall zone (seasonal rainfall >600 mm where economic crops are grown to offset the high cost of terrace construction and maintenance. In the medium and low rainfall zones (seasonal rainfall 400–600 mm and 300–400 mm, terracing for water erosion control is generally not needed on cultivated land less than 10% in slope where wheat and barley crops are normally grown; however, pioneer research projects are needed to assess the feasibility of terraces of the level (detention type to conserve rain water in these two zones for a more successful rainfed farming venture.

A change in landscape: Lessons learned from abandonment of ancient Wari agricultural terraces in Southern Peru.

Science.gov (United States)

Londoño, Ana C; Williams, Patrick Ryan; Hart, Megan L

2017-11-01

Ancient agricultural terrace practices have survived for millennia, sustaining populations through extreme climatic shifts and political regime changes. In arid regions with abrupt relief such as Southern Peru, agricultural terracing is undergoing a resurgence, as has seen revitalization of once abandoned terrace and hydraulic systems. Wari terraces at Cerro Baul provide clues to past cultural practices. They also document sustainable farming practices by using resilient land management techniques which can help combat desertification and degradation of arable lands. Three abandoned Wari terrace systems were mapped using microtopographic methods, the erosion patterns examined, the states of preservation compared, and then the design contrasted with modern terracing practices in the Moquegua Valley. In order to negate the harmful effects of desertification, rehabilitation and reconstruction of these terraces using ancient knowledge and techniques may be necessary. Rehabilitation must be conducted with consideration for preservation of cultural patrimony that may be encountered within the terrace treads or riser structures. With future climatic shifts impacting vulnerable dryland areas more than others, the ability to resiliently respond to these changes may be found in the lessons learned from ancient farming techniques such as the Wari. Copyright © 2017 Elsevier Ltd. All rights reserved.

Worrying about ‘Vertical Landscapes’: Terraced Olive Groves and Ecosystem Services in Marginal Land in Central Italy

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Elena Brunori

2018-04-01

Full Text Available Terraced Mediterranean areas are distinctive man-made landscapes with historical and cultural relevance. Terraced land abandonment driven by physical and economic constraints had important ecological consequences. This study focuses on a marginal agricultural district in southern Latium, central Italy, where terracing dated back to the Roman period and olive groves are the main agricultural use. A diachronic assessment of land-use transformations was carried out to identify landscape dynamics and drivers of change around terraced land. Terraced landscape systems (TLS, derived from spatial aggregation of neighboring terraced patches, have been analyzed for landscape transformations considering slope as the main stratification variable. Structural and functional characteristics of TLS were analyzed using a landscape ecology approach. Soil bio-chemical indicators were finally assessed to study the impact of terraced olive agro-ecosystems on soil-related ecosystems services. The empirical findings outlined that TLS in central Italy are sensitive to urbanization and land abandonment. Cultivated terraces prevailed up to gentle-medium slope land, uncultivated and wooded areas dominated terraces on steep slopes. In this context, poly-cultural olive groves proved to be a cropping system particularly resilient to global change, irrespective of land slope. Terraced systems and extensive poly-cultural olive groves play a role in preserving ecosystem integrity, landscape quality, soil functionality and, therefore, environmental sustainability.

Radiocarbon dating of floodplain and young terraces alluvial sediments of Latvia rivers

International Nuclear Information System (INIS)

Eberhards, G.; Saltupe, B.

2000-01-01

This paper include new information about alluvial sediments structure and radiocarbon data of some Latvia free-meandering rivers (Gauja, Ogre, Liela and Maza Jugla, Daugava) floodplains and first terraces. In this present study we examined Gauja river floodplains in the different geomorphological and geological areas. Radiocarbon dating add the fact that the high level floodplain (4-5 m) formation and sediment accumulation take place 3000-5000 years before present (BP) middle level floodplains formed 1500-2100 years BP. Investigations show that one river terraces and floodplains with same relative height have a several absolute age. The rivers crossed same hypsometrical regions (highlands, lowlands) downstream in lowlands alluvial terraces performed as floodplains or from from floodplains to terraces with same height. On the highest, middle and in the lower parts of the rivers with free - meandering channel to - day the dynamic balance of the channel processes exits 4000-5000 years. (author)

Terrace Geochemistry at the Shiprock, New Mexico, Disposal Site - WM2017-17232 Initial Phase

Energy Technology Data Exchange (ETDEWEB)

Kautsky, Mark [USDOE Office of Legacy Management, Washington, DC (United States); Ranalli, Tony [Navarro Research and Engineering, Oak Ridge, TN (United States); Dander, David [Navarro Research and Engineering, Oak Ridge, TN (United States); Miller, David [Navarro Research and Engineering, Oak Ridge, TN (United States)

2017-03-08

The objective of this investigation was to identify and differentiate potential non- mill-related water inputs to a shallow terrace groundwater system through the use of aqueous chemical and isotopic tracers at a former uranium- and vanadium-ore processing facility. Terrace groundwater in the vicinity of the Shiprock, New Mexico, site is hypothesized to be largely anthropogenic because natural rates of recharge in the terrace are likely insufficient to sustain a continuous water table in the terrace alluvial system, as observed in several analogue terrace locations east of the site and in response to post-mill dewatering efforts across the site. The terrace is composed of alluvial sand and gravel and weathered and unweathered Mancos Shale. Terrace groundwater exists and flows in the alluvium and to a much less extent in the Mancos Shale. Historical data established that in both the terrace and floodplain below the terrace, mill-derived uranium and sulfate is found primarily in the alluvium and the upper portion of the weathered Mancos Shale. Groundwater extraction is being conducted in the vicinity of former mill operations and in washes and seeps to dewater the formation and remove contamination, thus eliminating these exposure pathways and minimizing movement to the floodplain. However, past and present contribution of non-mill anthropogenic water sources may be hindering the dewatering effort, resulting in reduced remedy effectiveness. Groundwater source signatures can be determined based on chemical and isotopic ratios and are used to help identify and delineate both mill and non-mill water contributions. Aqueous chemical and isotopic tracers, such as 234U/238U activity ratios and uranium concentrations, δ34S sulfate and sulfate concentrations, tritium concentrations, and δ2Hwater and δ18O water are being used in this Phase I study. The aqueous chemical and isotopic analysis has identified areas on the terrace where groundwater is derived from mill

Modelling and simulation of Holocene marine terrace development in Boso Peninsula, central Japan

Science.gov (United States)

Noda, Akemi; Miyauchi, Takahiro; Sato, Toshinori; Matsu'ura, Mitsuhiro

2018-04-01

In the southern part of Boso Peninsula, central Japan, we can observe a series of well-developed Holocene marine terraces. We modeled the development of these marine terraces by considering sea-level fluctuation and steady land uplift. The evolution of coastal landform is generally described as follows: altitude change = - erosion + deposition - sea-level rise + land uplift. In this study, the erosion rate is supposed to be proportional to the dissipation rate of wave energy, and the deposition rate of eroded materials to decay exponentially as they are transported seaward. The rate of sea-level rise is given by the time derivative of a sea-level curve obtained from the sediment core records of oxygen isotope ratios. Steady plate subduction generally brings about steady crustal uplift/subsidence independently of earthquake occurrence, and so the land-uplift rate is regarded as time independent on a long-term average. Our simulation results show that a pair of sea cliff and abrasion platform is efficiently formed about a stationary point of the sea-level curve. The Holocene sea-level curve has four peaks and three troughs, and so basically seven terraces are formed one by one during the past 10,000 yr. However, when the land-uplift rate is low, most of the terraces formed at older times sink in the sea. When the land-uplift rate is high, the overlap and/or reverse of older and younger terraces occur frequently, and so the correspondence between the age and present altitude of terraces is not necessarily one-to-one. Taking the land-uplift rate to be 3-4 mm/yr, we can reproduce a series of well-developed Holocene marine terraces in Boso Peninsula independently of coseismic uplifts. From these simulation results, we may conclude that the Holocene marine terraces in Boso Peninsula were developed as a result of the composite process of sea-level fluctuation and steady coastal uplift.

The River Mondego terraces at the Figueira da Foz coastal area (western central Portugal): Geomorphological and sedimentological characterization of a terrace staircase affected by differential uplift and glacio-eustasy

DEFF Research Database (Denmark)

Ramos, Anabela M.; Cunha, Pedro P.; Cunha, Lúcio. S.

2012-01-01

A geomorphological and sedimentological characterization of the River Mondego terraces in the Figueira da Foz coastal area, Portugal, is presented. The relief is dominated by a Pliocene a marine sandy unit ~ 10–15 m thick, reaching ~ 250 m a.s.l., that covers a shore platform surface. The River...... of terrace genesis in this coastal area should be dominated by glacio-eustasy whereby episodic valley incision would have been determined by periods of very low sea-level, probably at ~ 460–410 ka (T3/T4; MIS12), ~ 200–125 ka (T4/T5; MIS6) and 100–14 ka (T5/Recent alluvial infill; late MIS5, MIS4, MIS3......-gravels and silts, but also some colluvium at the top of each terrace. The younger terraces (T3, T4 and T5) show better developed sedimentary structures and less sedimentary matrix; the sedimentary features are indicative of both fluvial and coastal environments (estuary and beach, as nowadays). Under conditions...

Nutrient Losses by Runoff and Sediment from the Taluses of Orchard Terraces

NARCIS (Netherlands)

Duran Zuazo, V.H.; Martinez Ray, A.; Aguilar Ruiz, J.

2004-01-01

The nutrient fluxes of nitrate, ammonium, phosphorus and potassium in runoff and sediments were evaluated over a two-year period (1999¿2000) on the taluses of terraces, in a zone of intense subtropical orchard cultivation (SE Spain). The erosion plots were located on a terrace of 214% (65°) slope,

Terrace erosion and sediment transport model: a new tool for soil conservation planning in bench-terraced steeplands.

NARCIS (Netherlands)

van Dijk, A.I.J.M.; Bruijnzeel, L.A.

2003-01-01

Despite widespread bench-terracing soil erosion remains a major problem in Java's uplands. To elucidate the causes for this lack of impact, runoff and erosion processes were studied at a variety of spatial scales within a volcanic catchment in West Java. Research indicated that soil loss occurs via

Uplift characterization in an inland area based on information of terrace distribution. Case study in the Mid Niigata region

International Nuclear Information System (INIS)

Hataya, Ryuta; Hamada, Takaomi

2009-01-01

We have investigated the correlation and chronology of fluvial terraces, and characteristics of terrace distribution around active structures, in the Mid Niigata region. Making much of geomorphologic and geologic information, such as morphology and continuity of terrace plains, weathering of terrace gravels, gives to appropriately interpretation of tephra data. Then, at both sides of the active structure, characteristics of terrace distribution are quite different. It indicates that terrace distribution is useful information to evaluate fault activity. Furthermore, uplift estimation for the last 100,000 years is given by terrace distribution information and relative heights of fluvial terraces, and can be applied to evaluation the fault activity. For example, using the uplift index of the values of relative height between terraces, we estimated that the uplift difference on the both side of the Muikamachi fault during late Quaternary was more than 40m. It suggests that the slip rate of the Muikamachi fault is more than 0.4m/10 3 year. The viewpoint and method shown in this paper reflected to the upgrade of the air-photo interpretation for active fault survey. (author)

Electronic-Reconstruction-Enhanced Tunneling Conductance at Terrace Edges of Ultrathin Oxide Films.

Science.gov (United States)

Wang, Lingfei; Kim, Rokyeon; Kim, Yoonkoo; Kim, Choong H; Hwang, Sangwoon; Cho, Myung Rae; Shin, Yeong Jae; Das, Saikat; Kim, Jeong Rae; Kalinin, Sergei V; Kim, Miyoung; Yang, Sang Mo; Noh, Tae Won

2017-11-01

Quantum mechanical tunneling of electrons across ultrathin insulating oxide barriers has been studied extensively for decades due to its great potential in electronic-device applications. In the few-nanometers-thick epitaxial oxide films, atomic-scale structural imperfections, such as the ubiquitously existed one-unit-cell-high terrace edges, can dramatically affect the tunneling probability and device performance. However, the underlying physics has not been investigated adequately. Here, taking ultrathin BaTiO 3 films as a model system, an intrinsic tunneling-conductance enhancement is reported near the terrace edges. Scanning-probe-microscopy results demonstrate the existence of highly conductive regions (tens of nanometers wide) near the terrace edges. First-principles calculations suggest that the terrace-edge geometry can trigger an electronic reconstruction, which reduces the effective tunneling barrier width locally. Furthermore, such tunneling-conductance enhancement can be discovered in other transition metal oxides and controlled by surface-termination engineering. The controllable electronic reconstruction can facilitate the implementation of oxide electronic devices and discovery of exotic low-dimensional quantum phases. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Terrace Agriculture of the Hani People – Cultural Heritage of the South-West China

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Kladovshchikova Mariya Evgenyevna

2015-04-01

Full Text Available The article presents the features of terrace agriculture of Hani and Yi indigenous minorities, living in the Yunnan province in the South-West China, just a step away from the Laos and Vietnam boundaries. The cultural landscape of the Hani rice terraces, included into the UNESCO World Heritage List in 2013 (Cultural Landscape of Honghe Hani Rice Terraces, expresses the conservation of the minorities’ course of life during the last 1 300 years. The geological framework, climate patterns and conform type of vegetation predefine the specific character of natural conditions necessary for terrace agriculture and red rice growth – the most important crop within the region. At that, the landscape picture which fully reflects the season fluctuations of regional subtropical climate, also facilitates to aesthetic and romantic perception forming, symbolizing man-made environment integral and interlaced into natural landscape. The special focus is made on the description of terraced slopes unique morphology and ancient land cultivation technologies for the essential regional culture – red rice. Preservation of centuries-old traditions of efficient agriculture makes it possible to achieve integration of cultural and natural landscapes, that seamlessly comprises the ethnic minorities’ life, as well as to prevent development of erosion and landslide slope processes. The elements of the traditional Hani people way of life, including ritual customs associated with terrace agriculture, are particularly described.

Quantification of the effect of terrace maintenance on soil erosion: two seasons of monitoring experiments in Cyprus

Science.gov (United States)

Camera, Corrado; Djuma, Hakan; Zoumides, Christos; Eliades, Marinos; Charalambous, Katerina; Bruggeman, Adriana

2017-04-01

In the Mediterranean region, rural communities in topographically challenging sites have converted large areas into dry-stone terraces, as the only way to develop sustainable agriculture. Terraces allow softening the steep mountainous slopes, favoring water infiltration and reducing water runoff and soil erosion. However, population decrease over the past 30 years has led to a lack of maintenance of the terraces and the onset of a process of land degradation. The objective of this study is the quantification of the effect of terrace maintenance on soil erosion. We selected two terraces - A and B, 11 and 14 m long, respectively - for monitoring purposes. They are located in a small catchment (10,000 m2) in the Troodos Mountains of Cyprus, at an elevation of 1,300 m a.s.l., and cultivated with vineyards, which is the main agricultural land use of the region. We monitored soil erosion by means of sediment traps, which are installed along 1-m long sections of terrace. We monitored four sections on terrace A and seven on terrace B. During the first monitoring season (winter 2015/16), on terrace A the traps caught sediment of two collapsed and two standing sections of dry-stone wall. The catchment areas of one set of traps (degraded and non-degraded) were closed by a 1x4-m2 plot, to relate erosion rates to a known draining area. On terrace B the traps were all open and caught four collapsed and three standing sections. Also, we installed a weather station (5-minute rainfall, temperature, and relative humidity) and 15 soil moisture sensors, to relate soil erosion processes with climate and (sub)surface hydrology. From the open traps, we observed that soil loss is on average 8 times higher from degraded terrace sections than from standing, well maintained sections, which in our case study corresponds to an 87% reduction of soil loss due to terrace maintenance. If we compare data from the two closed plots, we obtain a much higher soil loss ratio (degraded/standing) of 56

Opportunities and Benefits of Green Balconies and Terraces in Urban Conditions

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Mladenović Emina

2017-12-01

Full Text Available This study tested the hypothesis that a third dimension of urban gardening, in the form of green terraces and balconies, is of immense importance to the public well-being, mitigating climate changes and contributing to a more pleasant life in highly urbanized zones. By means of a concise questionnaire, a total of 82 respondents of different age groups (20-70 years of age were surveyed about their opinion on green terraces, balconies, and roofs, i.e. the plants and flowers they incorporate. The fieldwork and survey responses facilitated the design of ten different spaces in various conditions. The results obtained enabled the selection of plants which could be used in given conditions, depending on wind, insolation, shade, ground levels, precipitation, etc. A total of three different terraces (out of ten and three different balconies (out of ten were enrolled in the study. The research results indicate that ten minutes of gardening could reduce stress levels and restore the positive energy of residents. An increase in the overall plant diversity exerts positive aesthetic and ecological effects. Inner-city areas are often sparsely vegetated, devoid of plants, and densely built-up, thus terraces and balconies have the potential to be retrofitted with suitable greenery.

Physical data of soil profiles formed on late Quaternary marine terraces near Santa Cruz, California

Science.gov (United States)

Munster, Jennie; Harden, Jennifer W.

2002-01-01

The marine terraces in and around Santa Cruz, California, represent a set of well-preserved terraces formed as a product of geology, sea level, and climate. A marine terrace begins as a wave cut platform. Eustatic sea level changes, seacliff erosion, and tectonic uplift work together to generate marine terraces. "When a wave-cut platform is raised (due to tectonic activity) above sea level and cliffed by wave action it becomes a marine terrace" (Bradley, 1957, p. 424). During glacial periods, eustatic sea level is estimated to have dropped by 150 meters (Fairbanks, 1989). Cliff retreat measured from aerial photographs between 1930 and 1980 vary from 0.0 to 0.2 m yr–1 (Best and Griggs, 1991). Estimates of uplift rates along the Santa Cruz coastline vary from 0.10 to 0.48 m kyr–1 (Bradley and Griggs, 1976; Weber and others, 1999). Uplift mechanisms include coseismic uplift associated both with a reverse component of slip on the steeply SW dipping Loma Prieta fault in the restraining bend of the San Andreas Fault and a small component of reverse slip on the steeply SE dipping San Gregorio fault (Anderson and Menking 1994). Previous work studying physical properties on these terraces include Pinney and others (in press) and Aniku (1986) and Bowman and Estrada (1980). Sedimentary deposits of the marine terraces are a mixture of terrestrial and marine sediments but generally consist of a sheet of marine deposits overlying the old platform and a wedge of nonmarine deposits banked against the old sea cliff (Bradley, 1957). Bedrock underlying the terraces in the Santa Cruz area is generally either Santa Margarita Sandstone or Santa Cruz Mudstone. The Santa Margarita Sandstone represents an upper Miocene, transgressive, tidally dominated marine-shelf deposit with crossbedded sets of sand and gravel and horizontally stratified and bioturbated invertebrate-fossils beds (Phillips, 1990). The siliceous Santa Cruz Mudstone, of late Miocene age, conformably overlies the Santa

Spatio-temporal relation between landslide occurrence and abandoned or not maintained agricultural terraces in the Moldavian Plateau, NE Romania

Science.gov (United States)

Ciprian Margarint, Mihai; Santangelo, Michele; Niculita, Mihai; Bucci, Francesco

2016-04-01

Terraced landscapes are one of the most obvious human-shaped landscapes, mainly used to reduce the negative impact of soil erosion due to uncontrolled runoff and shallow landslides occurrence. Nevertheless, as the recent literature emphasizes, these old best practices can transform into a potential hazard for soil degradation, if not appropriately maintained. In Moldavian Plateau (NE Romania), agricultural terraces were built after the 1960s for landslide, soil erosion and runoff control, mainly in connection with construction of reservoirs, for increasing their operation time. Usually, the slope reduction was obtained by construction of cut-off ditches, hillside ditches, intermittent terraces, bench terraces, broad-based terraces, vineyardand orchard terraces. Due to the dry climatic setting, to the lack of hard rocks for construction, and to the generally light earth moving machinery available for construction, terraces are generally characterized by a small escarpment (0.5m to 1m), and a relatively short lateral extension (5 to 40 m). When the terraces were maintained, the backslope was typically covered with grass. When, after the 1990s, the lands were returned to the initial owners, the vegetation cover of the terraces was no more maintained, and the terraces themselves were progressively abandoned, due to lack of funds. Accurate landslide mapping on high resolution LiDAR DEM derived images, allowed to produce geomorphological inventories in 5 test cases, representative of the whole study area. In each inventory, landslides were classified based on type and relative age based on published classification schemes. We investigate the spatial and temporal relation between landslides occurrence and terraces, based on the spatial interactions of landslides of different ages and terraces. Results reveal that terraces were built, both on landslide-free and landslide-bearing slopes, and that frequently landslides and gullies develop on terraced slopes. Reactivations of

Integrating Geomorphic and Social Dynamics in the Analysis of Anthropogenic Landforms: Examining Landscape Evolution of Terrain Modified by Agricultural Terracing

Science.gov (United States)

Glaubius, J.; Maerker, M.

2016-12-01

Anthropogenic landforms, such as mines and agricultural terraces, are impacted by both geomorphic and social processes at varying intensities through time. In the case of agricultural terraces, decisions regarding terrace maintenance are intertwined with land use, such as when terraced fields are abandoned. Furthermore, terrace maintenance and land use decisions, either jointly or separately, may be in response to geomorphic processes, as well as geomorphic feedbacks. Previous studies of these complex geomorphic systems considered agricultural terraces as static features or analyzed only the geomorphic response to landowner decisions. Such research is appropriate for short-term or binary landscape scenarios (e.g. the impact of maintained vs. abandoned terraces), but the complexities inherent in these socio-natural systems requires an approach that includes both social and geomorphic processes. This project analyzes feedbacks and emergent properties in terraced systems by implementing a coupled landscape evolution model (LEM) and agent-based model (ABM) using the Landlab and Mesa modeling libraries. In the ABM portion of the model, agricultural terraces are conceptualized using a life-cycle stages schema and implemented using Markov Decision Processes to simulate the changing geomorphic impact of terracing based on human decisions. This paper examines the applicability of this approach by comparing results from a LEM-only model against the coupled LEM-ABM model for a terraced region. Model results are compared by quantify and spatial patterning of sediment transport. This approach fully captures long-term landscape evolution of terraced terrain that is otherwise lost when the life-cycle of terraces is not considered. The coupled LEM-ABM approach balances both environmental and social processes so that the socio-natural feedbacks in such anthropogenic systems can be disentangled.

A geomorphic and tectonic model for the formation of the flight of Holocene marine terraces at Mahia Peninsula, New Zealand

Science.gov (United States)

Berryman, Kelvin; Clark, Kate; Cochran, Ursula; Beu, Alan; Irwin, Sarah

2018-04-01

At Table Cape, Mahia Peninsula, North Island, New Zealand, four marine terraces have been uplifted coseismically during the past 3500 years. Detailed facies assessment of the terrace coverbed sequence coupled with identification of modern analogues on the active shore platform were used to infer the process of marine terrace formation and to estimate the timing and amount of past uplift events (earthquakes). The modern platform can be subdivided into seven depositional zones: subtidal, outer platform, intertidal sand pockets, inner platform, high-tide, mid-storm, and storm beach. Terrace coverbeds were characterised from two trenches excavated across the full width of the uplifted terrace sequence. Off-lapping packages of high tidal, mid-storm, and storm beach sediments were most common. Outer platform sediments occurred only rarely near the base of some uplifted shore platforms. Overlying the marine sediments were near-horizontal terrestrial deposits of airfall tephra (on the two highest terraces), subsoil, topsoil, rare wedges of colluvial sediment (slopewash) shed from terrace risers, and an anomalous deposit possibly emplaced by a tsunami. Fifty-one radiocarbon ages, obtained from molluscs in the marine coverbeds, showed a general pattern of seaward-younging across the coastal plain and across each terrace and a less pronounced pattern of decreasing age upward in each coverbed sequence. The distinctive stepped geomorphology of the terraces, the facies and age structure of the terrace deposits and historical earthquake causation of similar terraces elsewhere in New Zealand provided the data to invoke an earthquake-driven model for terrace formation. Marine terrace development following an uplift event involved rapid cutting of a new intertidal shore platform and generally regressive deposition of high-tide to storm beach deposits. Following further uplift, the platform became a geomorphic terrace (above marine influence) and was then mantled by terrestrial

Vertical slip rates of active faults of southern Albania inferred from river terraces

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Oswaldo Guzmán

2014-02-01

Full Text Available Fluvial terraces of Shkumbin, Devoll, Osum and Vjosa rivers (southern Albania and northwestern Greece are studied in order to quantify the vertical slip rates of the large active faults of the Dinaric-Albanic-Hellenic Alpine fold belt. The spatial and temporal variations of the incision rates along these rivers were estimated from the geomorphological mapping of the Quaternary sediments, the geometry and the dating of the terraces. Eleven terraces levels were identified in Albania from 68 geochronological ages already published or acquired for this work. The five lower terraces of the four studied rivers are well dated (10 new and 23 already published ages. These terraces are younger than 30 ka and their remnants are numerous. Their restoration allows estimating the regional trend of incision rate and the identification of local shifts. We argue that these shifts are linked to the active tectonics when they coincide with the faults already mapped by previous authors. Vertical slip rates for eight active faults in southern Albania are thus estimated for the last 19 ka and vary from ~0.1 to ~2 mm/a. The Lushnje Tepelene Thrust, that extends more than 120 kilometers, has a throw rate that varies from 0.2 to 0.8 mm/a, whereas the active faults of the extensional domain are segmented but are very active, with throw rates reaching locally 2 mm/a.

Sea-level standstill and dominant hermatypic coral from the holocene raised reef terraces at the Kikai Island, Ryukyu Islands

International Nuclear Information System (INIS)

Hongo, Chuki

2010-01-01

Coral reef terraces are one of the best recorders of biological response to environmental change events (e.g., sea-level changes). Kikai Island provides a rare opportunity to show biological and ecological frameworks (e.g., competition, coexistence, and succession) during a recent geological period. The island is fringed by raised Holocene raised reef terraces, which formed as a result of periodic tectonic uplifts. This study aims to characterize the spatial and temporal changes of corals at this island during the Holocene. The analysis is based on topographical and biological data obtained for the three sites (Shidooke, Kadon, and Nakugama reefs). Three raised reef terraces (Terrace II, III, and IV) grew from 7300 to 4500 years ago (during 2800 years), from 4500 to 2900 years ago (during 1600 years), and from 2900 to 1800 years ago (during 1100 years), respectively. Terrace II and III were uplifted 1-2 m around 4500 years ago and around 2900 years ago. Terrace IV was uplifted 1-2 m around 1800 years ago. The modern reef has been composed of corals for 1800 years. Sixteen coral genera and 53 species were recorded from the reef terraces. Terrace III and IV were dominated by four coral species (A. digitifera, A. robusta, G. retiformis, and F. stelligera), but Terrace II was predominantly composed of A. digitifera and A. robusta. These biological and ecological variations between the terraces represent a growth strategy responding to differences of reef growth time and/or insolation. (author)

Fluvial terrace dating using in situ cosmogenic {sup 21}Ne

Energy Technology Data Exchange (ETDEWEB)

Sexton, E. [Univ. of Illinois, Chicago, IL (United States); Caffee, M. [Lawrence Livermore National Lab., CA (United States)

1994-12-01

Through the analysis of cosmic-ray produced radio-genic and stable nuclide concentrations, specifically {sup 21}Ne, we hope to date certain geomorphic features located along the tributaries of the Colorado River in the Eastern Grand Canyon and the Rainbow Plateau located in Utah. During the Quaternary, the Colorado River system was fed by glacial melting and run-off from the Wind River and Colorado Mountain Ranges. Past periods of aggradation allowed the emplacement of terrace features from debris flow activity. By dating such features we can further constrain the timing of key events such as river down cutting, terrace genesis/exposure age, and rates of surface erosion. Knowing the age and elevation of each terrace we can determine an average rate of down cutting of this river system. This, in turn, will offer information regarding alpine glaciation which is a sensitive indicator of global climate change. Studying the relative concentrations of these isotopic species in surface rocks can be useful in researching glacial periodicity and the relationship between solar activity and climate.

A landscape character assessment of three terraced areas in Campania region, Italy

Science.gov (United States)

Gravagnuolo, Antonia; Ronza, Maria; Di Martino, Ferdinando; De Rosa, Fortuna

2017-04-01

Agricultural terraces represent the territorial structure of many cultural landscapes in the Campania region, Italy. Historic urban/rural settlements and hydraulic-agrarian systems have been developed on mountains and hills, producing diverse cultural landscapes depending on the specific geological, pedological and geomorphological characteristics, which influenced the character and functions of terraces. These unique landscapes are multi-functional and provide many ecosystem services: provisioning (food, water retention, building materials); regulating and maintenance (hydrogeological stability, soil fertility, protection from soil erosion, maintenance of genetic diversity, habitat); cultural services (heritage and traditional knowledge conservation, tourism and recreation, spiritual experience, education, aesthetic quality). Three terraced landscapes in Campania are analysed, which present a rich diversity in the geological structure and formal/functional characteristics: the Roccamonfina vulcanic area, a highly fertile and lapillous soil; the Monte di Bulgheria, a clay-rich area; and finally the well-known UNESCO World Heritage site of the Amalfi Coast, a calcareous, steep rock faced area. A landscape character assessment of the three sites is processed, identifying the biophysical structure of the sites, natural systems and land use, and cultural and anthropic elements. Terraced landscapes in Campania can be regenerated, taking again an active social and economic role for the society, enhancing their multifunctionality as a key source of wellbeing. Ecosystem services are mapped and evaluated to assess benefits and costs in a multidimensional framework. Spatial analysis in GIS environment supports this process, providing a decision-support tool for mapping and assessment of terraced landscapes, to convert their actual and potential value into a resource of economic sustainable development.

Spatial patterns of 137Cs inventories and soil erosion from earth-banked terraces in the Yimeng Mountains, China

International Nuclear Information System (INIS)

Zhang, Yunqi; Long, Yi; An, Juan; Yu, Xingxiu; Wang, Xiaoli

2014-01-01

The Yimeng Mountains is one of China's most susceptible regions to soil erosion. In this region, slopes are composed of granite- or gneiss-derived soils that are commonly cultivated using earth-banked terraces. Based on the 137 Cs measurement for nine reference cores, the present study analysed the spatial patterns of 137 Cs inventory and soil erosion using 105 sampling points in a seven-level earth-banked terrace system. The mean 137 Cs inventory, standard deviation, coefficient of variation, and allowable error for the nine reference cores were 987 Bq m −2 , 71 Bq m −2 , 7%, and 6%, respectively, values that may reflect the heterogeneity of the initial 137 Cs fallout deposit. Within each terrace, the 137 Cs inventory generally increases from the rear edge to the front edge, accompanied by a decrease in the erosion rate. This results from planation by tillage and rainfall runoff during the development of the earth-banked terraces. Across the entire seven-level terrace system, 137 Cs inventories decrease from the highest terrace downwards, but increase in the lower terraces, whereas erosion rate displays the opposite trend. These trends are the result of the combined effects of the earth-bank segmented hillslope, the limited protection of the earth banks, and rainfall runoff in combination with tillage. The high coefficients of variation of 137 Cs inventories for the 21 sampling rows, with a mean value of 44%, demonstrate the combined effects of variations in original microtopography, anthropogenic disturbance, the incohesive soils weathered from underlying granite, and the warm climate. Although earth-banked terraces can reduce soil erosion to some extent, the estimated erosion rates for the study area are still very high. - Highlights: • Earth-banked terraces are widely distributed in the Chinese Yimeng Mountains. • Spatial patterns of 137 Cs and erosion reflect terrace development processes. • Earth-banked terraces may limit soil erosion but rates

Phenotype diversity analysis of red-grained rice landraces from Yuanyang Hani's terraced fields, China

Science.gov (United States)

Li, Lianjie; Cheng, Long

2017-10-01

There are many areas in the world have terraced fields, Yuanyang Rani's terraced fields are examples in the world, and their unique ecological diversity is beyond other terraced fields, rice landraces are very rich. In order to provide useful information for protection and utilization of red-grained rice landraces from Rani's terraced fields, 61 red-grained rice landraces were assessed based 20 quantitative traits. Principal component analysis (PCA) suggested that 20 quantitative characters could be simplified to seven principal components, and their accumulative contribution ration amounted to 78.699%. The first principal component (PC1) explained 18.375% of the total variance, which was contributed by filled grain number, 1000-grain weight, spikelets per panicle, secondary branch number, grain length, and grain thickness. PC2 accounted for 16.548% of the variance and featured flag leaf width, flag leaf area, panicle neck length and primary branch number. These traits were the most effective parameters to discriminate individuals. At the request of the proceedings editor and with the approval of all authors, article 040111 titled, "Phenotype diversity analysis of red-grained rice landraces from Yuanyang Hani's terraced fields, China," is being retracted from the public record due to the fact that it is a duplication of article 040110 published in the same volume.

Changes in Soil Quality and Hydrological Connectivity Caused by the Abandonment of Terraces in a Mediterranean Burned Catchment

Directory of Open Access Journals (Sweden)

Aleix Calsamiglia

2017-09-01

Full Text Available Wildfires and agricultural activities are relevant factors affecting soil quality, hydrological cycle and sedimentary dynamics. Land abandonment leads to afforestation, which increases fire risk and land degradation. However, no studies have yet evaluated the effect of combining the two factors, which occur frequently in Mediterranean ecosystems. This study assessed the changes in soil quality caused by the abandonment of terraces in two microcatchments (<2.5 ha affected distinctly by wildfires (once and twice burned and in an unburned control microcatchment by analyzing soil quality parameters, biochemical indices and spatial patterns of hydrological and sediment connectivity. Soil samples were collected in thirty-six plots (25 m2 representing terraced and non-terraced areas within these microcatchments. Unburned non-terraced plots had higher organic matter content and higher microbiological and enzymatic activities than other plots. Plots in abandoned terraces had lower soil quality indices, regardless of the fire effect. Land abandonment induced changes in the spatial patterns of hydrological connectivity, leading to concentrated runoff, enhanced erosion and soil degradation. Fire also negatively affected soil quality in both terraced and non-terraced plots. However, microbiological communities had different positive post-fire recovery strategies (growth and activity, depending on the previous soil conditions and land uses, which is indicative of the resilience of Mediterranean soil ecosystems.

Brownian Motion of 2D Vacancy Islands by Adatom Terrace Diffusion

International Nuclear Information System (INIS)

Morgenstern, Karina; Laegsgaard, Erik; Besenbacher, Flemming

2001-01-01

We have studied the Brownian motion of two-dimensional (2D) vacancy islands on Ag(110) at temperatures between 175 and 215K. While the detachment of adatoms from the island and their diffusion on the terrace are permitted in this temperature range, the periphery diffusion of single adatoms is prohibited. The present scanning tunneling microscopy results provide the first direct experimental proof that the Brownian motion of the islands follows a simple scaling law with terrace diffusion being the rate limiting process. The activation energy of the vacancy island motion is determined to 0.41eV

The evolution of crop cultivation and paleoenvironment in the Longji Terraces, southern China: Organic geochemical evidence from paleosols.

Science.gov (United States)

Jiang, Yongjian; Li, Shijie; Chen, Wei; Cai, Desuo; Liu, Yan

2017-11-01

The Longji ancient agricultural terraces in the Longji Mountain area (Guilin, southern China), which still remain in use, are famous for their magnificent terraced landscape with a mix of ecosystem and human inhabitation. Previous research has revealed the genesis and preliminary paleoenvironmental record of the agricultural terraces, but little is known about variations in crop cultivation over time. In this study, organic geochemical analyses and radiocarbon dating of an aggradational cultivated soil from a terrace profile were used to explore crop type variation and relevant paleoenvironmental change during the period of cultivation on the Longji Terraces. Hydroponic farming with rice (C 3 ) planting has been the dominant cultivation mode since the initial construction of the terraces. Warm-dry climate contributed to the growth of drought-tolerant crop (C 4 ) cultivation in the late 15th century. Temperature deterioration during the Little Ice Age had a negative impact on dry and hydroponic farming activities from the late 15th century to the late 19th century, while climate warming after the Little Ice Age promoted the redevelopment of hydroponic farming. Copyright © 2016 Elsevier Ltd. All rights reserved.

Do agricultural terraces and forest fires recurrence in Mediterranean afforested micro-catchments alter soil quality and soil nutrient content?

Science.gov (United States)

E Lucas-Borja, Manuel; Calsamiglia, Aleix; Fortesa, Josep; García-Comendador, Julián; Gago, Jorge; Estrany, Joan

2017-04-01

Bioclimatic characteristics and intense human pressure promote Mediterranean ecosystems to be fire-prone. Afforestation processes resulting from the progressive land abandonment during the last decades led to greater biomass availability increasing the risk of large forest fires. Likewise, the abandonment and lack of maintenance in the terraced lands constitute a risk of land degradation in terms of soil quantity and quality. Despite the effects of fire and the abandonment of terraced lands on soil loss and physico-chemical properties are identified, it is not clearly understood how wildfires and abandonment of terraces affect soil quality and nutrients content. Microbiological soil parameters and soil enzymes activities are biomarkers of the soil microbial communitýs functional ability, which potentially enables them as indicators of change, disturbance or stress within the soil community. The objective of this study was to investigate the effects of terracing (abandoned and non-abandoned) on the soil enzyme activities, microbiological soil parameters and soil nutrients dynamics in three Mediterranean afforested micro-catchments (i.e., fire recurrence in the last 20 years; i.e., unburned areas, burned once and burned twice. The combination of the presence of terraces and the recurrence of forest fire, thirty-six plots of 25 m2 were sampled along the these three micro-catchments collecting four replicas at the corners of each plot. The results elucidated how non-terraced and unburned plots presented the highest values of soil respiration rate and extracellular soil enzymes. Differences between experimental plots with different forest fire recurrence or comparing terraced and unburned plots with burned plots were weaker in relation to biochemical and microbiological parameters. Soil nutrient content showed an opposite trend with higher values in terraced plots, although differences were weaker. We conclude that terraced landscapes present poorer soil quality

History of the great Kanto earthquakes inferred from the ages of Holocene marine terraces revealed by a comprehensive drilling survey

Science.gov (United States)

Komori, Junki; Shishikura, Masanobu; Ando, Ryosuke; Yokoyama, Yusuke; Miyairi, Yosuke

2017-08-01

We measured the emergence ages of four marine terraces in the Chikura lowland, which lies to the southeast of the Boso Peninsula, in eastern Japan, to reevaluate the history of the great earthquake occurrences along the Sagami Trough over the past 10,000 years. The dates of the marine terraces are measured via radiocarbon dating of shell fossils obtained from the marine deposits. The sampling method employed in this study collects core samples using a dense and systematic drilling survey, which increased the reliability when correlating shell fossils with marine terraces. In addition, radiocarbon dating was performed with accelerator mass spectrometry, which produces more highly accurate measurements than those measured in previous studies. Moreover, we explored the surface profiles of the terraces with detailed digital elevation model (DEM) data obtained using LiDAR. The maximum emergence ages of the marine terraces were dated at 6300 cal yBP, 3000 cal yBP, and 2200 cal yBP from the top terrace excepting the lowest terrace (which was estimated at AD1703). In addition, another previously unrecognized terrace was detected between the highest and the second terrace in both the dating and the geomorphological analyses and was dated at 5800 cal yBP. The newly obtained ages are nearly a thousand of years younger than previously estimated ages; consequently, the intervals of the great earthquakes that occurred along the Sagami Trough are estimated to be much shorter and more varied than those of previous estimations. This result revises the data used in the current assessment of the probabilities of earthquakes along the Sagami Trough, which could devastate the Tokyo metropolitan area. Furthermore, it demonstrates that the current approach could be a powerful tool to increase the accuracy of assessments of the other areas with depositional marine terraces.

Changes in hydrological connectivity due to vegetation recovery and wall collapse in abandoned terraced fields

Science.gov (United States)

Lana-Renault, Noemí; López-Vicente, Manuel; Oranjuren, Rafael; Ángel Llorente, José; Ruiz-Flaño, Purificación; Arnáez, José

2017-04-01

Agricultural terraces have been built in mountain regions worldwide in order to provide a larger surface for cultivation, improve water availability and reduce soil erosion, as they favour infiltration and reduce runoff and sediment connectivity from hillslopes to streams. In many Mediterranean countries, farmland abandonment has led to progressive natural revegetation and, in terraced slopes, due to a lack of maintenance, to a collapse of the water conservation structures, often followed by small mass movements and gullying. Little is known about the effect of such failures on the hydrological system, especially at catchment scale. The aim of this study is to contributing to fill in this gap by exploring the effect of vegetation recovery and terrace failure on hydrological connectivity in a small catchment (192 ha) in northern Spain mostly occupied by abandoned terraced fields. For this purpose, we applied a modified version of the Borselli's index of runoff and sediment connectivity (IC). Besides using the C-RUSLE factor, as used by many authors, we tested the inclusion of an infiltration component (Kf) to assess the landscape-weighting factor. The Kf factor accounted for the high infiltration rates observed in the terraced soils and was estimated using the permeability classes of the K-RUSLE factor. A 2x2 m resolution DEM was used to capture the terraced fields and run the IC model. Following the recommendation of Cavalli et al. (2015), we used the D-infinity flow accumulation algorithm (Tarboton, 1997) to represent the real flow paths, especially on hillslopes, where divergent flow predominates, and on stream channels. To ensure the continuity of the flow path lines, local sinks were filled in with the algorithm of Planchon & Darboux (2001) that preserved a minimum slope gradient of 0.01 degrees. Finally, linear landscape elements such as stonewalls, rock outcrops, and trails and forest roads were also considered. The IC was calculated for the current scenario

Processes of Terrace Formation on the Piedmont of the Santa Cruz River Valley During Quaternary Time, Green Valley-Tubac Area, Southeastern Arizona

Science.gov (United States)

Lindsey, David A.; Van Gosen, Bradley S.

2010-01-01

In this report we describe a series of stepped Quaternary terraces on some piedmont tributaries of the Santa Cruz River valley in southeastern Arizona. These terraces began to form in early Pleistocene time, after major basin-and-range faulting ceased, with lateral planation of basin fill and deposition of thin fans of alluvium. At the end of this cycle of erosion and deposition, tributaries of the Santa Cruz River began the process of dissection and terrace formation that continues to the present. Vertical cutting alternated with periods of equilibrium, during which streams cut laterally and left thin deposits of channel fill. The distribution of terraces was mapped and compiled with adjacent mapping to produce a regional picture of piedmont stream history in the middle part of the Santa Cruz River valley. For selected tributaries, the thickness of terrace fill was measured, particle size and lithology of gravel were determined, and sedimentary features were photographed and described. Mapping of terrace stratigraphy revealed that on two tributaries, Madera Canyon Wash and Montosa Canyon Wash, stream piracy has played an important role in piedmont landscape development. On two other tributaries, Cottonwood Canyon Wash and Josephine Canyon Wash, rapid downcutting preempted piracy. Two types of terraces are recognized: erosional and depositional. Gravel in thin erosional terraces has Trask sorting coefficients and sedimentary structures typical of streamflood deposits, replete with bar-and-swale surface topography on young terraces. Erosional-terrace fill represents the channel fill of the stream that cuts the terrace; the thickness of the fill indicates the depth of channel scour. In contrast to erosional terraces, depositional terraces show evidence of repeated deposition and net aggradation, as indicated by their thickness (as much as 20+ m) and weakly bedded structure. Depositional terraces are common below mountain-front canyon mouths where streams drop their

A Review of Heat Transfer in Terraced Houses of Tropical Climate

Directory of Open Access Journals (Sweden)

Azzmi Norazura Mizal

2014-01-01

Full Text Available Heat is the process of energy circulation and replacement of air from hot to cold. In tropical climates, more heat is received because of the location of Malaysia of the equatorial line. Excessive heat in buildings causes discomfort to the occupants in tropical climate. Tropical rainforest climate receives higher solar radiation and terrestrial radiation reaching the building envelopes contributes to this problem. The design of the building should be more concern on reducing this heat. This paper provides a review of heat contribution in a terraced house indoor environment for tropical climate. A good comfortable home is part of the sustainable development agenda to improve the quality of life. Terraced houses are the most living quarters in mass living scheme for urban areas. The incoming solar energy from the sun into the building surface cannot be changed, therefore a consideration of passive building design need to be applied in terraced house design. Data collection gathered from this literature survey will assist to identify problems of discomfort occupant. This strategy would assist in improving the building industry in promoting sustainable development in Malaysia.

Spatial patterns of (137)Cs inventories and soil erosion from earth-banked terraces in the Yimeng Mountains, China.

Science.gov (United States)

Zhang, Yunqi; Long, Yi; An, Juan; Yu, Xingxiu; Wang, Xiaoli

2014-10-01

The Yimeng Mountains is one of China's most susceptible regions to soil erosion. In this region, slopes are composed of granite- or gneiss-derived soils that are commonly cultivated using earth-banked terraces. Based on the (137)Cs measurement for nine reference cores, the present study analysed the spatial patterns of (137)Cs inventory and soil erosion using 105 sampling points in a seven-level earth-banked terrace system. The mean (137)Cs inventory, standard deviation, coefficient of variation, and allowable error for the nine reference cores were 987 Bq m(-2), 71 Bq m(-2), 7%, and 6%, respectively, values that may reflect the heterogeneity of the initial (137)Cs fallout deposit. Within each terrace, the (137)Cs inventory generally increases from the rear edge to the front edge, accompanied by a decrease in the erosion rate. This results from planation by tillage and rainfall runoff during the development of the earth-banked terraces. Across the entire seven-level terrace system, (137)Cs inventories decrease from the highest terrace downwards, but increase in the lower terraces, whereas erosion rate displays the opposite trend. These trends are the result of the combined effects of the earth-bank segmented hillslope, the limited protection of the earth banks, and rainfall runoff in combination with tillage. The high coefficients of variation of (137)Cs inventories for the 21 sampling rows, with a mean value of 44%, demonstrate the combined effects of variations in original microtopography, anthropogenic disturbance, the incohesive soils weathered from underlying granite, and the warm climate. Although earth-banked terraces can reduce soil erosion to some extent, the estimated erosion rates for the study area are still very high. Copyright © 2014 Elsevier Ltd. All rights reserved.

Extraction of Terraces on the Loess Plateau from High-Resolution DEMs and Imagery Utilizing Object-Based Image Analysis

Directory of Open Access Journals (Sweden)

Hanqing Zhao

2017-05-01

Full Text Available Abstract: Terraces are typical artificial landforms on the Loess Plateau, with ecological functions in water and soil conservation, agricultural production, and biodiversity. Recording the spatial distribution of terraces is the basis of monitoring their extent and understanding their ecological effects. The current terrace extraction method mainly relies on high-resolution imagery, but its accuracy is limited due to vegetation coverage distorting the features of terraces in imagery. High-resolution topographic data reflecting the morphology of true terrace surfaces are needed. Terraces extraction on the Loess Plateau is challenging because of the complex terrain and diverse vegetation after the implementation of “vegetation recovery”. This study presents an automatic method of extracting terraces based on 1 m resolution digital elevation models (DEMs and 0.3 m resolution Worldview-3 imagery as auxiliary information used for object-based image analysis (OBIA. A multi-resolution segmentation method was used where slope, positive and negative terrain index (PN, accumulative curvature slope (AC, and slope of slope (SOS were determined as input layers for image segmentation by correlation analysis and Sheffield entropy method. The main classification features based on DEMs were chosen from the terrain features derived from terrain factors and texture features by gray-level co-occurrence matrix (GLCM analysis; subsequently, these features were determined by the importance analysis on classification and regression tree (CART analysis. Extraction rules based on DEMs were generated from the classification features with a total classification accuracy of 89.96%. The red band and near-infrared band of images were used to exclude construction land, which is easily confused with small-size terraces. As a result, the total classification accuracy was increased to 94%. The proposed method ensures comprehensive consideration of terrain, texture, shape, and

THE INFLUENCE OF PRIVACY REGULATION ON URBAN MALAY FAMILIES LIVING IN TERRACE HOUSING

OpenAIRE

Ahmad Hariza Hashim; Zaiton Abdul Rahim

2008-01-01

This paper reports on behavioral norms and territoriality as part of behavioral and environmental mechanisms used to regulate privacy among urban Malay families living in terrace housing. In-depth interview was employed involving 11 case studies of Malay families living in three-bedroom two-storey terrace housings in the urban areas. Findings indicate that while most of the behavioral norms employed to regulate privacy are consistent with Malay cultural norms and religious belief, there are a...

Chronology of fluvial terrace sequences for large Atlantic rivers in the Iberian Peninsula (Upper Tagus and Duero drainage basins, Central Spain)

Science.gov (United States)

Silva, Pablo G.; Roquero, Elvira; López-Recio, Mario; Huerta, Pedro; Martínez-Graña, Antonio M.

2017-06-01

This work analyses the chronology of fluvial terrace sequences of the two most important fluvial basins from central Spain draining to the Atlantic Ocean (Upper Tagus and Duero drainage basins). Both basins evolved under similar Mediterranean climatic conditions throughout the Pleistocene and present comparable number of fluvial terraces (16-17) after excluding the higher terrace levels of the Tagus (T1-T5) entrenched in the Raña surface. These higher ;rañizo terraces; was formed in response to fan-head trenching in this high alluvial piedmont (+220 m) and therefore not properly controlled by Quaternary fluvial downcutting. The study accomplishes the implementation of multiple regression analyses for terrace height-age relationships. To transform relative terrace heights above the present river thalwegs (i.e. +100 m) in numerical ages a ;height-age transference function; has been developed on the basis of preliminary statistical geochronological approaches proposed for Central Spain. The resultant height-age transference function gather 73 published geochronological data for terrace sequences, featuring a 3rd Order Polynomial Function (R2 0.90). This function describes the overall trend of valley downcutting for the last c. 2.3 Ma in Central Spain and is used to assign numerical ages to terrace levels at different relative elevation.

Assessing the Reliability of Land-Use Data in Slovenia: A Case Study of Terraced Landscapes

Science.gov (United States)

Ažman Momirski, Lucija

2017-10-01

Land use relates to the exploitation of land through human activity in the landscape. Land use is also one of the best indicators of a landscape’s structure and processes. Land cover comprises manmade surfaces, agricultural areas, forest and semi-natural areas, wetlands, and bodies of water. In Slovenia more than half of the land (63%) is forested. Manmade surfaces represent less than 5%. A large proportion of relatively inaccessible forest is the main reason why society had a less critical impact on forests in the past in Slovenia in comparison to the majority of central European countries. Regarding the high-quality landscape in the country, Slovenia’s natural features are characterized by a mix of forest and farmland. These land categories (i.e., complex cultivation patterns and land principally used for agriculture with significant areas of natural vegetation) cover 23% of Slovenia. Land-use data for farmland are gathered and provided to the relevant institutions by landowners, who are not specialists in land-use data. In addition, land use is only a two-dimensional tool, which does not recognize elevation differences and terraced slopes. Terraced areas are either omitted from the inventory of land-use data because landowners do not report them, or they are included in the inventory because landowners do not realize that their land is not terraced. Consequently, the differences between the official data on vineyards, orchards, and olive groves on terraces and actual terraced slopes with such land use may differ significantly.

A 30000 yr record of erosion rates from cosmogenic 10Be in middle European river terraces

NARCIS (Netherlands)

Schaller, M.; Blanckenburg, von F.; Veldkamp, A.; Tebbens, L.A.; Hovius, N.; Kubik, P.W.

2002-01-01

Cosmogenic 10Be in river-borne quartz sand records a time-integrated erosion rate representative of an entire drainage basin. When sequestered in a terrace of known age, paleo-erosion rates may be recovered from the nuclide content of the terrace material. Paleo-erosion rates between 30 and 80

Terrace system of the middle and lower Sázava River

Czech Academy of Sciences Publication Activity Database

Balatka, B.; Štěpančíková, Petra

2006-01-01

Roč. 6, č. 1 (2006), s. 69-81 ISSN 1335-9541 Institutional research plan: CEZ:AV0Z30460519 Keywords : fluvial terrace system * geomorphological evolution * Sázava River Subject RIV: DB - Geology ; Mineralogy

Conceptual Design of Fertilizer Applicator for Oil Palm on Terrace Cultivation

Science.gov (United States)

Hermawan, W.

2018-05-01

The mechanical application of fertilizer for oil palm planted on terraces is still constrained by the narrow path which is difficult to pass by a power spreader. The objective of this research was to develop a conceptual design of fertilizer applicator for oil palm planted on terraces. The design requirements were developed based on a) terrace and track conditions, b) fertilizers and fertilization conditions, c) available prime movers, and d) user needs. Five design concepts were obtained: 1) an applicator with left and right arms to distribute the fertilizer, 2) an all-terrain vehicle equipped with a manually operated fertilizer injector, 3) an applicator equipped with a hole digger, 4) an applicator equipped with a shovel, and 5) an applicator equipped with a rotary tiller. The concepts were evaluated and compared with the current power spreader. The evaluation results showed that the applicator equipped with a rotary tiller had the most advantages on the expected criteria. The final design concept uses a 110 cm wide mini crawler tractor as the prime mover and is equipped with a hopper and a spinner disk for metering and conveying the fertilizer, and a 20 cm wide rotary tiller in the front of the machine.

Single-grain and multi-grain OSL dating of river terrace sediments in the Tabernas Basin, SE Spain

DEFF Research Database (Denmark)

Geach, M.R.; Thomsen, Kristina Jørkov; Buylaert, Jan-Pieter

2015-01-01

River terraces represent important records of landscape response to e.g. base-level change and tectonicmovement. Both these driving forces are important in the southern Iberian Peninsula. In this study,Optically Stimulated Luminescence (OSL) dating was used to date two principal river terraces...

Middel Pleistocene to Holocene fluvial terrace development and uplift-driven valley incision in the SE Carpathians, Romania

NARCIS (Netherlands)

Necea, D.; Fielitz, W.; Andriessen, P.A.M.; Dinu, C.

2013-01-01

This study reveals that in the SE Carpathians terrace development and fluvial incision during the Middle Pleistocene-Holocene are predominantly controlled by tectonic uplift as shown by terrace distributions and uplift amounts and rates. The work focuses on a transect from the internal nappes and

Effect of Coffee Pulp Compost and Terrace on Erosion, Run off and Nutrients Loss from Coffee Plantation in Lahat Regency, South Sumatra

Directory of Open Access Journals (Sweden)

Siti Masreah Bernas

2011-05-01

Full Text Available On some coffee plantations in Lahat Regency South Sumatra, in some places the farmers did not apply agricultural practices, such as tillage, conservation practices, and fertilizers. Many researches have been done to study about effects of organic fertilizer on soil nutrients content and plant growth as well as and the impacts of terrace on soil water content, run-off and erosion. However, there was less research in the highland area. Whereas the possibility of run off, erosion and nutrient leaching the high land area was high. Thus, it was important to apply terrace and organic coffee pulp in this farm. The aims of this research were to determine the effect of terrace and organic fertilizer on run off and soil erosion, nutrients loss and nutrient content in coffee leaves. Terrace system and organic fertilizer were applied on a one year old coffee plantation in Lahat Regency. Before the treatment applied, coffee pulp as organic fertilizer was decomposed in the chamber for about 2 months. The experiment was conducted in factorial in a Randomized Block Design with two factors. The first factor was coffee pulp compost (0, 3, and 6 Mg ha-1, and the second factor was type of terrace (without, individual, and bund terraces. The size of each plot was 2 m width and 10 m length. Data was analysed by using LSD (Least Significant Different test. The result shows that bund terrace reduced runoff and erosion significantly up to 79% (for run off water and 78% (for eroded soil compared to without terrace. Organic fertilizer did not affect run off and soil erosion. This may be caused by properties of coffee pulp compost which were fine particulates and the dosages of application were too low to cover soil suface. Bund terrace decreased significantly N, P, K nutrients in soil loss (sediment. The amount of N loss was reduced from 3.37 kg ha-1 per four months (without terrace to about 0.75 kg ha-1 per four months (bund terrace. Terrace and organic fertilizer did

Linking terrace geomorphology and canopy characteristics in the Peruvian Amazon using high resolution airborne remote sensing (Invited)

Science.gov (United States)

Chadwick, K.; Asner, G. P.

2013-12-01

The Peruvian Amazon is home to over half a million square kilometers of forest, nearly three quarters of which is supported by terrace landforms with variable histories. Characteristics of these terrace ecosystems have been contrasted with neighboring floodplain systems along riverine transportation corridors, but the ecological complexity within these terrace landscapes has remained largely unexplored. Airborne remote measurements provide an opportunity to consider the relationship between forest canopy characteristics and geomorphic gradients at high resolution over large spatial extents. In 2011 the Carnegie Airborne Observatory (CAO) was used to map a large section of intact lowland humid tropical forest in the southwestern Peruvian Amazon, including over nine thousand hectares of terrace forest. The CAO collected high-fidelity imaging spectroscopy data with its Visible-Shortwave Imaging Spectrometer (VSWIR) and digital elevation and canopy structure data with its high-resolution dual waveform LiDAR. These data, supplemented with field data collection, were used to quantify relationships between forest canopy traits and geomorphic gradients. Results suggest that both spectral properties of the canopy with known relationships to canopy chemistry, including pigment and nutrient concentrations, and canopy structural traits, including vegetation height and leaf area, are associated with geomorphic characteristics of this terrace landscape.

River terrace development in the NE Mediterranean region (Syria and Turkey): Patterns in relation to crustal type

Science.gov (United States)

Bridgland, David R.; Demir, Tuncer; Seyrek, Ali; Daoud, Mohamad; Abou Romieh, Mohammad; Westaway, Rob

2017-06-01

It is widely recognized that the optimal development of river terraces globally has been in the temperate latitudes, with NW and Central Europe being areas of particular importance for the preservation of such archives of Quaternary environmental change. There is also a growing consensus that the principal drivers of terrace formation have been climatic fluctuation against a background of progressive (but variable) uplift. Nonetheless river terraces are widely preserved in the Mediterranean region, where they have often been attributed to the effects of neotectonic activity, with a continuing debate about the relative significance of fluctuating temperature (glacials-interglacials) and precipitation (pluvials-interpluvials). Research in Syria and southern-central Turkey (specifically in the valleys of the Tigris and Ceyhan in Turkey, the Kebir in Syria and the trans-border rivers Orontes and Euphrates) has underlined the importance of uplift rates in dictating the preservation pattern of fluvial archives and has revealed different patterns that can be related to crustal type. The NE Mediterranean coastal region has experienced unusually rapid uplift in the Late Quaternary. The relation between the Kebir terraces and the staircase of interglacial raised beaches preserved along the Mediterranean coastline of NW Syria reinforces previous conclusions that the emplacement of the fluvial terrace deposits in the Mediterranean has occurred during colder climatic episodes.

Porosity prediction from seismic inversion, Lavrans Field, Halten Terrace

Energy Technology Data Exchange (ETDEWEB)

Dolberg, David M.

1998-12-31

This presentation relates to porosity prediction from seismic inversion. The porosity prediction concerns the Lavrans Field of the Halten Terrace on the Norwegian continental shelf. The main themes discussed here cover seismic inversion, rock physics, statistical analysis - verification of well trends, upscaling/sculpting, and implementation. 2 refs., 6 figs.

Refurbishment and extension of the terrace of Restaurant No.1

CERN Multimedia

2009-01-01

Work to refurbish and extend part of the terrace of Restaurant No.1 started in the first week of October and should last about two months. This is just a small part of the wide-ranging site infrastructure consolidation programme that began in April 2009. The new terrace, covering a surface area of 1770 m2 (compared with 1650 m2 today), is scheduled to be completed by the end of 2010 and will run all the way around the Restaurant No.1 extension. Work on the latter will affect part of Building 501 during the period from April to October 2010. The new dining room will seat some 275 additional customers (see picture). Part of the Cedars car-park will remain closed until some time in December to provide site access for trucks transporting construction materials, plant, etc. CERN Bulletin

Shading Performance on Terraced House Facades in Putrajaya, Malaysia

Directory of Open Access Journals (Sweden)

Hassan Ahmad Sanusi

2015-01-01

Full Text Available This study evaluates shading performance on house facades of selected three terraced houses in Putrajaya, Malaysia as the case studies. Terraced house type is selected for the case study because it is the most popular house type built in this country to house an increase of the urban population. Its total number built in urban area increases from 27% of the total dwellings in 1980 to 40% in 1990, and to slightly more than 60 per cent in 2000. The Case Study A, B, and C are atypical style of terraced house facade designs built in Putrajaya. These postmodern designs exhibit a range of complex geometric elements blending of colonial and traditional elements with colorful styles on the house facade. In this study, the time at which the sun path perpendicular to the house facade will be used to gain the results of shading performances when the house facades have their maximum exposure to the direct sunlight. The house facade was divided into two main parts which are opaque and glazing surface elements. The amount of shading area on the opaque and glazing surface was simulated using the SunTool program. In conclusion, the Case Study C had the highest average percentage of the shading area, which is 64.43%, followed by the Case Study A 60.41% and Case Study B 56.29%. These results showed that the facade designs had excellent horizontal shading elements with roof overhangs for high angle sunlight but they had weak vertical shading elements due to a lack of considerations of louvered elements to block low angle sunlight.

Methane dissociation on the steps and terraces of Pt(211) resolved by quantum state and impact site

Science.gov (United States)

Chadwick, Helen; Guo, Han; Gutiérrez-González, Ana; Menzel, Jan Paul; Jackson, Bret; Beck, Rainer D.

2018-01-01

Methane dissociation on the step and terrace sites of a Pt(211) single crystal was studied by reflection absorption infrared spectroscopy (RAIRS) at a surface temperature of 120 K. The C—H stretch RAIRS signal of the chemisorbed methyl product species was used to distinguish between adsorption on step and terrace sites allowing methyl uptake to be monitored as a function of incident kinetic energy for both sites. Our results indicate a direct dissociation mechanism on both sites with higher reactivity on steps than on terraces consistent with a difference in an activation barrier height of at least 30 kJ/mol. State-specific preparation of incident CH4 with one quantum of antisymmetric (ν3) stretch vibration further increases the CH4 reactivity enabling comparison between translational and vibrational activation on both steps and terraces. The reaction is modeled with first principles quantum theory that accurately describes dissociative chemisorption at different sites on the surface.

Exploring Controls on Sinuousity, Terraces and River Capture in the Upper Dajia River, Taiwan

Science.gov (United States)

Belliveau, L. C.; Ouimet, W. B.; Chan, Y. C.; Byrne, T. B.

2015-12-01

Taiwan is one of the most tectonically active regions in the world and is prone to landslides due to steep topography, large earthquakes and frequent typhoons. Landslides often affect and alter the river valleys beneath them, producing knickpoints on longitudinal river profiles, segmenting valleys into mixed bedrock-alluvial rivers and affecting river incision for tens to thousands of years. This study investigates the origin and evolution of complex channel morphologies, terraces and river capture along a 20km stretch of the Upper Da-Jia River in the Heping area of Taiwan. Through GIS analysis and field studies, we explore controls on river channel sinuousity, terrace development and river capture in relation to tectonic and climatic forcing, rock erodibility and landslides. High channel sinuousity is proposed as the result of a coupling between bank erosion and landslides. We discuss three types of landslide-induced meanders and increased sinuousity: (a) depositional-push meanders, (b) failure-zone erosional meanders, and (c) complex-erosional meanders. We also investigate spatial variation in channel morphology (slope, width) and the distribution and heights of river terraces within the Upper Da-Jia watershed associated with periods of widespread valley filling from landslide activity. Examples of river capture provide further evidence of the dynamic interactions between river incision, landslides and associated changes in channel morphology and terrace development within steep rapidly uplift, eroding and evolving mountain belts.

Multi-scale tectonic controls on fluvial terrace formation in a glacioeustatically-dominated river system: inference from the lower Min¿o terrace record

NARCIS (Netherlands)

Viveen, W.

2013-01-01

The general aim of this thesis is to untangle the interacting effects of climate, glacioeustacy, and regional, and local tectonics on fluvial terrace formation. The NW Iberian lower Miño River valley was chosen as a study site, because for this region, a very detailed, long-term,

Monitoring tectonic uplift and paleo-environmental reconstruction for marine terraces near Magaracik and Samandag, Hatay Province, Turkey

International Nuclear Information System (INIS)

Florentin, Jonathan A.; Blackwell, Bonnie A.B.; Blickstein, Joel I.B.; Skinner, Anne R.; Tueysuez, Okan; Tari, Ufuk; Can Genc, S.; Imren, Caner; Mo, Shirley; Huang, Yiwen E.W.; Kim, Maria

2014-01-01

Near Hatay, the Antakya-Samandag-Cyprus Fault (ASCF), East Anatolian and Dead Sea Fault Zones, the large faults that form the edges of the African, Anatolian, Cyprus and Arabian Plates, all produce large earthquakes, which have decimated Hatay repeatedly. Near Samandag, Hatay, differential vertical displacement on the ASCF has uplifted the southeastern side relative to northwestern side, producing large fault scarps that parallel the Asi (Orontes) River. Tectonic uplift coupled with Quaternary sea level fluctuations has produced several stacked marine terraces stranded above current sea level. This study dated 24 mollusc samples from 10 outcrops on six marine terraces near Samandag electron spin resonance (ESR). Ages were calculated using time-averaged and volumetrically averaged external dose rates, modelled by assuming typical water depths for the individual species and sediment thicknesses estimated from geological criteria. Uplift rates were then calculated for each fault block. At all the Magaracik terraces, the dates suggest that many shells were likely reworked. On the 30 m terrace at Magaracik IV (UTM 766588-3999880), Lithophagus burrows with in situ shells cross the unconformity. One such shell dated to 62 ± 6 ka, setting the minimum possible age for the terrace. For all the Magaracik terraces at ∼30 m above mean sea level (amsl), the youngest ages for the reworked shells, which averaged 60 ± 3 ka for six separate analyses, sets the maximum possible age for this unit. Thus, the terrace must date to 60-62 ± 3 ka, at the MIS 3/4 boundary when temperatures and sea levels were fluctuating rapidly. Older units dating to MIS 7, 6, and 5 likely were being eroded to supply some fossils found in this terrace. At Magaracik Dump (UTM 765391-4001048), ∼103 m amsl, Ostrea and other shells were found cemented in growth position to the limestone boulders outcropping there -1 , since MIS 5c. At Samandag Kurt Stream at 38 m amsl, molluscs were deposited fine sandy

Implementing automatic LiDAR and supervised mapping methodologies to quantify agricultural terraced landforms at landscape scale: the case of Veneto Region

Science.gov (United States)

Eugenio Pappalardo, Salvatore; Ferrarese, Francesco; Tarolli, Paolo; Varotto, Mauro

2016-04-01

Traditional agricultural terraced landscapes presently embody an important cultural value to be deeply investigated, both for their role in local heritage and cultural economy and for their potential geo-hydrological hazard due to abandonment and degradation. Moreover, traditional terraced landscapes are usually based on non-intensive agro-systems and may enhance some important ecosystems services such as agro-biodiversity conservation and cultural services. Due to their unplanned genesis, mapping, quantifying and classifying agricultural terraces at regional scale is often critical as far as they are usually set up on geomorphologically and historically complex landscapes. Hence, traditional mapping methods are generally based on scientific literature and local documentation, historical and cadastral sources, technical cartography and aerial images visual interpretation or, finally, field surveys. By this, limitations and uncertainty in mapping at regional scale are basically related to forest cover and lack in thematic cartography. The Veneto Region (NE of Italy) presents a wide heterogeneity of agricultural terraced landscapes, mainly distributed within the hilly and Prealps areas. Previous studies performed by traditional mapping method quantified 2,688 ha of terraced areas, showing the higher values within the Prealps of Lessinia (1,013 ha, within the Province of Verona) and in the Brenta Valley (421 ha, within the Province of Vicenza); however, terraced features of these case studies show relevant differences in terms of fragmentation and intensity of terraces, highlighting dissimilar degrees of clusterization: 1.7 ha on one hand (Province of Verona) and 1.2 ha per terraced area (Province of Vicenza) on the other one. The aim of this paper is to implement and to compare automatic methodologies with traditional survey methodologies to map and assess agricultural terraces in two representative areas of the Veneto Region. Testing different Remote Sensing

Optically stimulated luminescence dating of the Huanghe river terrace in Lanzhou basin

International Nuclear Information System (INIS)

Wang Ping; Yuan Daoyang; Liu Xinwang; Jiang Hanchao

2007-01-01

In this paper, profile observation and geologic strata structure analysis on the third level terrace at Fanjiaping on the south bank of the Huanghe River in the Lanzhou basin were reported, and systemically collected samples of fluvial sediments and the overlying diluvium and aeolian loess were analyzed by optically stimulated luminescence (OSL). The granulometric and magnetic susceptibility samples from the fine grain sedimentary layer at the middle of the profile were collected at a 2.5 cm interval. According to simplified multiple aliquot dating on fine grain quartz of 16 optically stimulated luminescence samples and electron spin resonance (ESR) dating of the underlying early fluvial layer, the following chronology results of the strata profile of the third terrace were obtained. The under- lying early fluvial layer is of gravels that belong to Fanjiaping formation in early and middle Pleistogene. The river-bed sedimentation of the Huanghe River started about 80,000 years ago. The accumulation of mainly proluvial sediments started about 70,000 years ago. And the continuous loess accumulation began about 55,000 years ago. The age of formation of the third terrace of Huanghe River was estimated at about 70,000 years, corresponding to the time between the last interglacial period and the last glacial period in the late Pleistocene. (authors)

Emergent Marine Terraces in Cebu Island, Philippines and Their Implications for Relative Sea Level Changes in the Late Quaternary

Science.gov (United States)

Ramos, N. T.; Sarmiento, K. J. S.; Maxwell, K. V.; Soberano, O. B.; Dimalanta, C. B.

2017-12-01

The remarkable preservation and extensive distribution of emergent marine terraces in the Philippines allow us to study relative sea level changes and tectonic processes during the Late Quaternary. While higher uplift rates and possible prehistoric coseismic events are recorded by emergent coral reefs facing subduction zones, the central Philippine islands are reported to reflect vertical tectonic stability as they are distant from trenches. To constrain the coastal tectonics of the central Philippine region, we studied emergent sea level indicators along the coasts of northern Cebu Island in Tabuelan, San Remigio, and Bogo City. Upper steps of marine terraces were interpreted from IFSAR-derived DEMs, in which at least two and seven steps were identified along the west (Tabuelan) and east (Bogo) coasts, respectively. In Tabuelan, two extensive terrace steps (TPT) were interpreted with TPT1 at 5-13 m above mean sea level (amsl) and TPT2 at 27-44 m amsl. Five to possibly seven terrace steps (BPT) were delineated in Bogo City with elevations from lowest (BPT1) to highest (BPT7) at BPT1: 4-6 m, BPT2: 12-18 m, BPT3: 27-33 m, BPT4: 39-46 m, BPT5: 59-71 m, BPT6: 80-92 m, and BPT7: 103-108 m amsl. These upper terraces are inferred to be Late Pleistocene in age based on an initial MIS 5e age reported for a 5-m-high terrace in Mactan Island. At some sites, even lower and narrower terrace surfaces were observed, consisting of cemented coral rubble that surround eroded and attached corals. These lower carbonate steps, with elevations ranging from 1 to 3 m amsl, further provide clues on relative sea level changes and long-term tectonic deformation across Cebu Island.

Terraced landscape: from an old best practice to a rising land abandoned-related soil erosion risk

Science.gov (United States)

Tarolli, Paolo; Preti, Federico; Romano, Nunzio

2013-04-01

Among the most evident landscape signatures of human fingerprint during the Holocene, the terraces related to agricultural activities deserve a great importance. Landscape terracing probably represents one of the oldest best practice primarily for crop production, but also for mitigating soil erosion and stabilizing hillslopes in landforms dominated by steep slopes. This technique is widely used in various parts of the world even under different environmental conditions. In some zones, terraced landscapes, because of their history and locations, can also be considered a historical heritage and a sort of "cultural landscape" to preserve, an absolutely value for tourism. To preserve their original role of soil erosion prevention, terraces should be properly designed built according to specific and sustainable engineering rules. Then, their maintenance is the most critical issue to deal with. It is well known from literature that terraced landscapes subject to abandonment would result in an increasing of terrace failure and related land degradation. If not maintained, a progressively increasing of gully erosion affects the structure of the walls. The results of this process is the increasing of connectivity and runoff. During the last few years and partly because of changing in the society perspective and migration toward metropolitan areas, some Countries have been affected by a serious and wider land abandonment with an increasing of soil erosion and derived landslide risk. Italy is one example. In this work, we consider three typical case studies of a terraced landscape where the lack of maintenance characterizing the last few years, increased the landslide risk with several problems to the population. The first case study is located along the renowed "Amalfi Coast" (a portion of land located near Salerno, southern Italy), the second is placed in the north of Toscana (a region located in Central Italy), and the third one along the so-called "Cinque Terre" (a region

Impacts of terracing on soil erosion control and crop yield in two agro-ecological zones of Rwanda

Science.gov (United States)

Rutebuka, Jules; Ryken, Nick; Uwimanzi, Aline; Nkundwakazi, Olive; Verdoodt, Ann

2017-04-01

Soil erosion remains a serious limiting factor to the agricultural production in Rwanda. Terracing has been widely adopted in many parts of the country in the past years, but its effectiveness is not yet known. Besides the standard radical (bench) terraces promoted by the government, also progressive terraces (with living hedges) become adopted mainly by the farmers. The aim of this study was to measure short-term (two consecutive rainy seasons 2016A and 2016B) run-off and soil losses for existing radical (RT) and progressive (PT) terraces versus non-protected (NP) fields using erosion plots installed in two agro-ecological zones, i.e. Buberuka highlands (site Tangata) and Eastern plateau (site Murehe) and determine their impacts on soil fertility and crop production. The erosion plot experiment started with a topsoil fertility assessment and during the experiment, maize was grown as farmer's cropping preference in the area. Runoff data were captured after each rainfall event and the collected water samples were dried to determine soil loss. Both erosion control measures reduced soil losses in Tangata, with effectiveness indices ranging from 43 to 100% when compared to the NP plots. RT showed the highest effectiveness, especially in season A. In Murehe, RT minimized runoff and soil losses in both seasons. Yet, the PT were largely inefficient, leading to soil losses exceeding those on the NP plots (ineffectiveness index of -78% and -65% in season A and B, respectively). Though topsoil fertility assessment in the erosion plots showed that the soil quality parameters were significantly higher in RT and NP plots compared to the PT plots on both sites, maize grain yield was not correlated with the physical effectiveness of the erosion control measures. Finally, the effectiveness of soil erosion control measures as well as their positive impacts on soil fertility and production differ not only by terracing type but also by agro-ecological zone and the management or

Morphotectonic architecture of an India–Madagascar breakup related anomalous submarine terrace complex on the southwest continental margin of India

Digital Repository Service at National Institute of Oceanography (India)

Yatheesh, V.; Kurian, P.J.; Bhattacharya, G.C.; Rajan, S.

, larger ‘Trivandrum Terrace (TT)’ and northerly, smaller Alleppey Terrace (AT). The multichannel seismic reflection data suggests a block-faulted basement and presence of a nearly N–S trending wide basement high in the central part of the Trivandrum...

A revision of mid-late Holocene marine terrace distribution and chronology at the Pakarae River mouth, North Island, New Zealand

International Nuclear Information System (INIS)

Wilson, K.; Berryman, K.R.; Litchfield, N.J.; Little, T.

2006-01-01

A suite of seven marine terraces at the Pakarae River mouth, New Zealand, provide evidence for the highest Holocene coastal uplift rates adjacent to the Hikurangi Subduction Zone. New elevation, coverbed stratigraphy, and age data allow for a timely revision of the distribution, nomenclature, and chronology of these terraces. Terrace correlation primarily is based on the elevation of the wave-cut strath. Terrace preservation either side of the river is more equal than previously proposed. The age of abandonment of each terrace is c. 7 ka (T1), 4.3 ka (T2), 3.5 ka (T3), 2.89 ka (T4), 1.6 ka (T5), 0.91 ka (T6), and <0.91 ka (T7). The average Holocene tectonic uplift rate at Pakarae is 3.2 ± 0.8 mm/yr. The abandonment of each terrace, from T2 to T7, probably took place after a discrete uplift event. The average time interval between these events is 850 ± 450 yr and the average uplift magnitude is 2.7 ± 1.1 m per event. We infer that uplift has been accommodated by slip on an offshore reverse fault. Normal slip on the Pakarae Fault, at right angles to the margin, occurs at a comparatively slower rate and has probably made little contribution to coastal uplift. (author). 35 refs., 9 figs., 2 tabs

Runoff and sediment generation on bench-terraced hillsides: measurements and up-scaling of a field-based model

Science.gov (United States)

van Dijk, A. I. J. M.; Bruijnzeel, L. A.; Vertessy, R. A.; Ruijter, J.

2005-05-01

Despite widespread bench-terracing, stream sediment yields from agricultural hillsides in upland West Java remain high. We studied the causes of this lack of effect by combining measurements at different spatial scales using an erosion process model. Event runoff and sediment yield from two 4-ha terraced hillside subcatchments were measured and field surveys of land use, bench-terrace geometry and storage of sediment in the drainage network were conducted for two consecutive years. Runoff was 3.0-3.9% of rainfall and sediment yield was 11-30 t ha-1 yr-1 for different years, subcatchments and calculation techniques. Sediment storage changes in the subcatchment drainage network were less than 2 t ha-1, whereas an additional 0.3-1.5 t ha-1 was stored in the gully between the subcatchment flumes and the main stream. This suggests mean annual sediment delivery ratios of 86-125%, or 80-104% if this additional storage is included. The Terrace Erosion and Sediment Transport (TEST) model developed and validated for the studied environment was parameterized using erosion plot studies, land use surveys and digital terrain analysis to simulate runoff and sediment generation on the terraced hillsides. This resulted in over-estimates of runoff and under-estimates of runoff sediment concentration. Relatively poor model performance was attributed to sample bias in the six erosion plots used for model calibration and unaccounted covariance between important terrain attributes such as slope, infiltration capacity, soil conservation works and vegetation cover.

Uplift rates of the marine terraces in the south coast of Japan deduced from in situ cosmogenic 10Be and 26Al

Science.gov (United States)

Yokoyama, Y.; Nagano, G.; Nakamura, A.; Maemoku, H.; Miyairi, Y.; Matsuzaki, H.

2015-12-01

Marine terraces are low-relief platforms located along coastal areas. They are formed by waves action with the changes in the relative sea level (RSL) that is affected by combined effects of the eustatic sea level (ESL) and the tectonic movements (e.g. uplift, subsidence and isostatic effect). Therefore, determining the ages and the elevations of the marine terraces allows us to reconstruct the ESL and/or the tectonic history of the study area. The Kii Peninsula and the southern coast of the Shikoku Island are located along the Nankai Trough where the Philippine Sea Plate is subducting under the Eurasian plate. There exist relatively well-preserved marine terraces along the coastal line with the elevation of ca. 50 -100 m. Because of this unique tectonic setting, the terraces are regarded as the suitable counterparts to reconstruct uplift history of the south coast of Japan. However, the ages of these terraces are poorly understood due to the lack of the ash layers that is suitable for the tephrochronology. In this study, we determine the age of the marine terraces using terrestrial in-situ cosmogenic radionuclides (TCN), 10Be and 26Al. This is the first age estimation of the marine terraces in Japan using TCN, allowing us to determine the uplift rates and the seismic history of the region.

Refining fault slip rates using multiple displaced terrace risers-An example from the Honey Lake fault, NE California, USA

Science.gov (United States)

Gold, Ryan D.; Briggs, Richard W.; Crone, Anthony J.; DuRoss, Christopher B.

2017-11-01

Faulted terrace risers are semi-planar features commonly used to constrain Quaternary slip rates along strike-slip faults. These landforms are difficult to date directly and therefore their ages are commonly bracketed by age estimates of the adjacent upper and lower terrace surfaces. However, substantial differences in the ages of the upper and lower terrace surfaces (a factor of 2.4 difference observed globally) produce large uncertainties in the slip-rate estimate. In this investigation, we explore how the full range of displacements and bounding ages from multiple faulted terrace risers can be combined to yield a more accurate fault slip rate. We use 0.25-m cell size digital terrain models derived from airborne lidar data to analyze three sites where terrace risers are offset right-laterally by the Honey Lake fault in NE California, USA. We use ages for locally extensive subhorizontal surfaces to bracket the time of riser formation: an upper surface is the bed of abandoned Lake Lahontan having an age of 15.8 ± 0.6 ka and a lower surface is a fluvial terrace abandoned at 4.7 ± 0.1 ka. We estimate lateral offsets of the risers ranging between 6.6 and 28.3 m (median values), a greater than fourfold difference in values. The amount of offset corresponds to the riser's position relative to modern stream meanders: the smallest offset is in a meander cutbank position, whereas the larger offsets are in straight channel or meander point-bar positions. Taken in isolation, the individual terrace-riser offsets yield slip rates ranging from 0.3 to 7.1 mm/a. However, when the offset values are collectively assessed in a probabilistic framework, we find that a uniform (linear) slip rate of 1.6 mm/a (1.4-1.9 mm/a at 95% confidence) can satisfy the data, within their respective uncertainties. This investigation demonstrates that integrating observations of multiple offset elements (crest, midpoint, and base) from numerous faulted and dated terrace risers at closely spaced

Refining fault slip rates using multiple displaced terrace risers—An example from the Honey Lake fault, NE California, USA

Science.gov (United States)

Gold, Ryan D.; Briggs, Richard; Crone, Anthony J.; Duross, Christopher

2017-01-01

Faulted terrace risers are semi-planar features commonly used to constrain Quaternary slip rates along strike-slip faults. These landforms are difficult to date directly and therefore their ages are commonly bracketed by age estimates of the adjacent upper and lower terrace surfaces. However, substantial differences in the ages of the upper and lower terrace surfaces (a factor of 2.4 difference observed globally) produce large uncertainties in the slip-rate estimate. In this investigation, we explore how the full range of displacements and bounding ages from multiple faulted terrace risers can be combined to yield a more accurate fault slip rate. We use 0.25-m cell size digital terrain models derived from airborne lidar data to analyze three sites where terrace risers are offset right-laterally by the Honey Lake fault in NE California, USA. We use ages for locally extensive subhorizontal surfaces to bracket the time of riser formation: an upper surface is the bed of abandoned Lake Lahontan having an age of 15.8 ± 0.6 ka and a lower surface is a fluvial terrace abandoned at 4.7 ± 0.1 ka. We estimate lateral offsets of the risers ranging between 6.6 and 28.3 m (median values), a greater than fourfold difference in values. The amount of offset corresponds to the riser's position relative to modern stream meanders: the smallest offset is in a meander cutbank position, whereas the larger offsets are in straight channel or meander point-bar positions. Taken in isolation, the individual terrace-riser offsets yield slip rates ranging from 0.3 to 7.1 mm/a. However, when the offset values are collectively assessed in a probabilistic framework, we find that a uniform (linear) slip rate of 1.6 mm/a (1.4–1.9 mm/a at 95% confidence) can satisfy the data, within their respective uncertainties. This investigation demonstrates that integrating observations of multiple offset elements (crest, midpoint, and base) from numerous faulted and dated terrace risers at closely spaced

Raised marine terraces in the Northern Calabrian Arc (Southern Italy: a ~ 600 kyr-long geological record of regional uplift

Directory of Open Access Journals (Sweden)

L. Cucci

2004-06-01

Full Text Available The Sibari Plain in the Northeastern Calabrian Arc displays a well-developed suite of marine terraces. This paper deals with i the identification and correlation of the terraces; ii their age assignment and a tentative reconstruction of the uplift history of the area; iii the relationships between terraces and major faults in the study area and between uplift in the Plain and pattern of Quaternary uplift throughout the Calabrian Arc. Identifying wavecut platforms and inner-edge fragments over a linear extent of ~ 100 km was achieved by photo interpretation, 1:25 000 scale map analyses and field survey. Morphological evidence led to the correlation of the identified fragments into five complete strandlines (numbered #1 to #5 lowest to highest, at elevations ranging from 60 m to ~ 650 m. Analysis of two parameters of the emerged platform-cliff systems, namely the platform-cliff ratio and the dissection percentage, further testifies that the two lowest terraces are strongly correlative. A 130 kyr AAR age of in situ fossil samples of Glycymeris collected at 114 m elevation within the deposit of Terrace #2 indicates a key correlation of T#2 with MIS 5.5 (the peak of the last interglacial, 124 kyr, i.e. an uplift rate of ~ 0.98 mm/yr for this strandline. The other four terraces have been tentatively associated with MIS 5.3, 7, 9 and 15. Geological observations independent of geochronological evidence provide consistent lower age boundaries for the terraces and supply further constraints to this interpretation. Investigating the relations between setting of the terraces and location of major tectonic structures in the region is suggestive of no recent activity of two previously recognized faults, the «Sangineto Line» and the «Corigliano-Rossano Line». Instead, some limited anomalies that affect the terraces are tentatively associated with the activity of the Castrovillari Fault. Therefore, sustained uplift has been the long-term dominant

Hillslope terracing effects on the spatial variability of plant development as assessed by NDVI in vineyards of the Priorat region (NE Spain).

Science.gov (United States)

Martínez-Casasnovas, José A; Ramos, María Concepción; Espinal-Utgés, Sílvia

2010-04-01

The availability of heavy machinery and the vineyard restructuring and conversion plans of the European Union Common Agricultural Policy (Commission Regulation EC no. 1227/2000 of 31 May 2000) have encouraged the restructuring of many vineyards on hillslopes of Mediterranean Europe, through the creation of terraces to favor the mechanization of agricultural work. Terrace construction requires cutting and filling operations that create soil spatial variability, which affects soil properties and plant development. In the present paper, we study the effects of hillslope terracing on the spatial variability of the normalized difference vegetation index (NDVI) in fields of the Priorat region (NE Spain) during 2004, 2005, and 2006. This index was computed from high-resolution remote sensing data (Quickbird-2). Detailed digital terrain models before and after terrace construction were used to assess the earth movements. The results indicate that terracing by heavy machinery induced high variability on the NDVI values over the years, showing significant differences as effect of the cut and fill operations.

The relationship between Holocene cultural site distribution and marine terrace uplift on the coast fringing Coastal Range, Taiwan

Science.gov (United States)

Yang, Hsiaochin; Chen, Wenshan

2013-04-01

According to the collision of Philippine Sea plate and Eurasia plate, a series of left-lateral active faults with reverse sense exists in the Longitudinal Valley of east Taiwan. The Holocene marine terraces along the east coast of the Coastal Range in Taiwan are well known for their very rapid uplift and record tectonic history of this active collision boundary. The Holocene marine terrace sequence resulting from successive sea level change and tectonic activation is subdivided into several steps where the highest and oldest terrace, back to ca 13,000yr BP, reaches up to ca 80 m above sea level, and the lower terraces are mostly erosional ones, overlain by less than 1m thick coral beds in situ. The uplift of the coast is very high, ranging from 5 to 10 m/ka. According to the fabrics of potsherds and geochronological data, the prehistoric cultures in eastern Taiwan could be classified into three stages: Fushan (ca 5000-3500yr BP), Peinan/Chilin (ca3500-2000yr BP), Kweishan (ca2000-1000 yr BP) and Jinpu (ca 1000-400yr BP) cultural assemblages respectively. A great difference exists between the various cultural stage, not only the pottery making techniques, but also the distributions of archaeological sites. Combined with the dynamic geomorphic evolution of marine terraces and the distribution of prehistoric culture sites on the east coast of the Coastal Range, a coastal migration trend could be established.

Possible schemes for solar-powered air-conditioning in 2-storey terrace houses

International Nuclear Information System (INIS)

Chu, C.M.; Bono, A.; Prabhakar, A.

2006-01-01

Space cooling is required all year round in the tropics, and probably accounts for a considerable proportion of the cost of electricity. Solar radiation can be channeled into cooling by photovoltaic powered systems and through the relatively new adsorption cycle technology. Two-storey terrace housing appear to have the greatest potential of introducing solar-powered cooling to residential homes. There are two schemes to cool a two-storey terrace housing: 1) By spraying water down the roof a tank, circulated by a pump powered by PV panels on the roof or 2) By replacing the roof with solar hot water collectors and use adsorption cooling chillers to produce air-conditioning for the entire block of terrace houses. In scheme number 1, a preliminary, rough technical evaluation showed that it is possible to pump water to the roof to flow down as a thin film and cool the roof by evaporation to about 40 degree C from about 70 degree C if without water evaporation at the highest insolation rate of the day. Scheme number 2, which uses adsorption chilling technology, requires communal sharing of the air-conditioning facility. The effect of collecting solar heat using the roof is two fold: to absorb solar energy for producing hot water and reducing excess heat input to the house. Preliminary costing demonstrates that solar-powered air-conditioning is within reach of commercialisation, bearing in mind that bulk purchases will dramatically lower the price of a product

Biologic origin of iron nodules in a marine terrace chronosequence, Santa Cruz, California

Science.gov (United States)

Schulz, M.S.; Vivit, D.; Schulz, C.; Fitzpatrick, J.; White, A.

2010-01-01

The distribution, chemistry, and morphology of Fe nodules were studied in a marine terrace soil chronosequence northwest of Santa Cruz, California. The Fe nodules are found at depths hyphae throughout the nodules, including organic structures incorporating fine-grained Fe oxides. The fine-grained nature of the Fe oxides was substantiated by M??ssbauer spectroscopy. Our microscopic observations led to the hypothesis that the nodules in the Santa Cruz terrace soils are precipitated by fungi, perhaps as a strategy to sequester primary mineral grains for nutrient extraction. The fungal structures are fixed by the seasonal wetting and dry cycles and rounded through bioturbation. The organic structures are compacted by the degradation of fungal C with time. ?? Soil Science Society of America. All rights reserved.

Podnikatelský plán - River Terrace Bar

OpenAIRE

Řezníček, Petr

2011-01-01

Even though it is often forgotten, the meaning of a business plan is of great importance to hospitality facilities and it should be created during an early stage of entrepreneurial activity. I focused on the operation of a 30s-style cabaret bar which is to be built as a part of prospective River Terrace hotel in Smichov, Prague. I analyse procedures that lead to the successful business plan in the theoretical part of my thesis. The practical part of my thesis contains a suitable plan for my c...

Two-Dimensional Nucleation on the Terrace of Colloidal Crystals with Added Polymers.

Science.gov (United States)

Nozawa, Jun; Uda, Satoshi; Guo, Suxia; Hu, Sumeng; Toyotama, Akiko; Yamanaka, Junpei; Okada, Junpei; Koizumi, Haruhiko

2017-04-04

Understanding nucleation dynamics is important both fundamentally and technologically in materials science and other scientific fields. Two-dimensional (2D) nucleation is the predominant growth mechanism in colloidal crystallization, in which the particle interaction is attractive, and has recently been regarded as a promising method to fabricate varieties of complex nanostructures possessing innovative functionality. Here, polymers are added to a colloidal suspension to generate a depletion attractive force, and the detailed 2D nucleation process on the terrace of the colloidal crystals is investigated. In the system, we first measured the nucleation rate at various area fractions of particles on the terrace, ϕ area . In situ observations at single-particle resolution revealed that nucleation behavior follows the framework of classical nucleation theory (CNT), such as single-step nucleation pathway and existence of critical size. Characteristic nucleation behavior is observed in that the nucleation and growth stage are clearly differentiated. When many nuclei form in a small area of the terrace, a high density of kink sites of once formed islands makes growth more likely to occur than further nucleation because nucleation has a higher energy barrier than growth. The steady-state homogeneous 2D nucleation rate, J, and the critical size of nuclei, r*, are measured by in situ observations based on the CNT, which enable us to obtain the step free energy, γ, which is an important parameter for characterizing the nucleation process. The γ value is found to change according to the strength of attraction, which is tuned by the concentration of the polymer as a depletant.

The activity of the Ulsan fault system based on marine terrace age study at the southeastern part of Korean peninsula

International Nuclear Information System (INIS)

Inoue, Daiei; Weon-Hack, Choi

2006-01-01

The activity evaluation of the Ulsan fault system (UFS) based on marine terrace age study in the southeastern part of Korean peninsula has been carried out. (1) The marine terrace distribution map along the southeastern coast of Korean peninsula has been distributed three wide terraces and several sub-terraces. The age of the above three terraces was determined by the discovery of wide tephras to be MIS5e, 7 and 9 from the lowest, respectively. (2) The active fault map along UFS was constructed. There will be the possibility that the UFS will be divided into three segments by the feature of lineaments. (3) The fault bounds between mountain at the eastern side, and plain at the western side in the most part of fault. It is interpreted that the UFS builds up the eastern mountain as a reverse movement fault. The latest activity of this fault system was clarified at the two localities by outcrop and trench investigation. The latest activity at Galgok-ri located in the northern part of the fault was occurred between 2,840 and 1,440 yBP. It was found to be between 7,470 and 2,990 yBP at Gaegok-ri, located in the central part of the fault. The latest activity at the Wangsan, which is between Galgok-ri and Gaegok-ri, was older than 7,000 yBP. The latest activity of the UFS differs between studied points. (4) The vertical slip rate of the UFS was calculated from the amount of vertical deformation and the age of terraces. Its range was between several cm to 20 cm in the 1000 years. This value corresponds to lower B and C class activity defined in Japan. (author)

Global synthesis of the classifications, distributions, benefits and issues of terracing

Science.gov (United States)

Wei Wei; Die Chen; Lixin Wang; Stefani Daryanto; Liding Chen; Yang Yu; Yonglong Lu; Ge Sun; Tianjiao Feng

2016-01-01

For thousands of years, humans have created different types of terraces in different sloping conditions, meant to mitigate flood risks, reduce soil erosion and conserve water. These anthropogenic landscapes can be found in tropical and subtropical rainforests, deserts, and arid and semiarid mountains across the globe. Despite the long history, the roles of and the...

10Be and 26Al dating of river terraces and quaternary incision rates in the Ardenne massif (eastern Belgium)

Science.gov (United States)

Rixhon, G.; Braucher, R.; Siame, L.; Bourlès, D.; Demoulin, A.

2009-04-01

Because of the lack of reliable chronological data, the Quaternary evolution of the hydrographic network of the Ardennes (western continuation of the Rhenish shield, western Europe) remains still poorly known. Therefore, we measured the cosmogenic nuclides content (10Be and 26Al) of terrace sediments of Ardennian rivers (Meuse, Ourthe & Amblève) in order to date several terrace levels and to better constrain the Quaternary incision of the network. Though these dating methods are successfully used to determine ages of superficial (e.g., glacial) deposits, dating of fluvial terraces remains difficult. Possible predepositional exposures of the sampled material (inherited 10Be and 26Al) may indeed bias the measurements towards higher nuclide concentrations while several postdepositional processes (burial, erosion) may cause a lowering of the 10Be and 26Al concentrations. In an attempt to overcome these difficulties, the selected fluvial deposits (six locations) were sampled using a profiling technique on as thick as possible sections (more than 3 m). While previous studies assigned an early middle Pleistocene age (around 800 ka) to the main terrace level in the Rhine-Meuse system, our 10Be dates for the same terrace level (according to geometrical correlation) in the Amblève River, a Meuse subtributary, are much younger (upper Pleistocene). To explain this age discrepancy, we suggest that the incision was strongly diachronous from the Meuse valley towards its Ardennian headwaters, as a result of a delayed upstream propagation of the incision wave when it passes tributary junctions.

Quaternary landscape evolution of the Helmand Basin, Afghanistan: Insights from staircase terraces, deltas, and paleoshorelines using high-resolution remote sensing analysis

Science.gov (United States)

Evenstar, L. A.; Sparks, R. S. J.; Cooper, F. J.; Lawton, M. N.

2018-06-01

The Helmand Basin in southern Afghanistan is a large (310,000 km2), structurally controlled, endorheically drained basin with a hyperarid climate. The basin hosts a high elevation ( 200 m) plateau (the Dasht-i Margo), 11 fluvial staircase terraces (T11 to T1), 7 delta systems (D1 to D7), and 6 paleolake shorelines (SL1 to SL6) within the Sistan Depression on the western side of the basin. Mapping and surveying of these features by remote sensing is integrated with geological observations to reconstruct Quaternary landscape evolution of the basin. The fluvial systems, deltas, and paleolake shorelines are correlated with one another and with the younger terraces (T7 to T1). The shape of fluvial longitudinal profiles changes depending on whether they formed pre-, syn-, or post-growth of the Koh-i Khannesin volcano on the southern margin of the Helmand River. The age of the volcano ( 0.6 Ma) and correlation of the terraces with the global history of glacial-interglacial cycles constrain the age of the younger terraces to the late Pleistocene and indicates that the older terraces are middle Pleistocene (dating back to 800 ka). The Helmand Basin once hosted a large lake, called here the Sistan paleolake, which at SL6 times and before had a surface area >50,000 km2. Since that time the lake elevation and area have decreased, evolving to the present-day dried out Sistan Depression with small ephemeral playa lakes. Episodic formation of terraces, deltas, and paleolake shorelines is attributed to changes in base level modulated by climate change related to Milankovitch cycles.

The hydrological response of a small catchment after the abandonment of terrace cultivation. A study case in northwestern Spain

Science.gov (United States)

Llorente-Adán, Jose A.; Lana-Renault, Noemí; Galilea, Ianire; Ruiz-Flaño, Purificacion

2015-04-01

Terrace construction for cultivation results in a complete transformation of the hillslopes to a series of flat sectors and almost vertical steps. This strategy, which involves a redistribution of soils and a re-organization of the drainage network, provides fertile soil over steep slopes, improves infiltration and controls overland flow under conditions of intense rainstorms. In Camero Viejo (north-western Iberian ranges) most of the hillslopes are occupied by terraced fields. During the XXth century, rural population declined and agricultural practices were abandoned. In this area, a small catchment (1.9 km2) was monitored in 2012 for studying how the abandonment of agricultural terraces affect water and sediment transfer from the hillslopes to the channels. Terraces occupy 40% of the catchment and are covered by sparse grass and shrubs. The equipment installed in the catchment registers continuously meteorological data, discharge and water table fluctuations. Data on suspended sediment transport is obtained by means of a rising-stage sampler. Here we present the hydrological results corresponding to the years 2012-13 and 2013-14. The hydrological response of the catchment was moderate (annual runoff coefficient < 0.20), which could be in part explained by the high evapotranspiration rates reported in the area. Lows flows were recorded in summer and autumn, when the water reserves of the catchment were dry, and high flows occurred from January, when the catchment became wetter. The shape of the hydrographs, with slow response times, moderate peakflows and long recession limbs suggested a large contribution of subsurface flow, probably favored by deep and well structured soils in the bench terraces. Soil saturation areas were not observed during the study period, suggesting that soil infiltration processes and subsurface flow are important, and that the drainage system of the terraces is probably well maintained. No suspended sediment has been collected so far

Luminescence dated Late Pleistocene wave-built terraces in northeastern Brazil

Directory of Open Access Journals (Sweden)

Kenitiro Suguio

2011-09-01

Full Text Available This study presents field and chronological investigations along the coast of northeastern Brazil from ~4°S to 9°S latitude, which corresponds to ~700 km of coastline under a semi-diurnal mesotidal regime. We investigated wave-built terrace deposits and dated sediments using the optically stimulated luminescence and thermoluminescence methods on quartz grains. The wave-built terraces yielded two main age groups: 200-230 ka and 100-130 ka, which we interpreted as depositional ages. We correlated these age groups with oxygen-isotope stages 7c and 5e, respectively. These events correspond to the antepenultimate and penultimate transgressions along the Brazilian coast. The deposits occur mainly in patches on low-lying flat plateaus along the littoral zone and incision valleys that cut across coastal tablelands. The altitude of the base of the 200-230 ka terraces ranges from 10 m above mean sea level (asl to -2m asl, whereas the base of the 100-130 ka varies from 12 m asl to -2 m asl. Both terraces were deposited in the foreshore and upper shoreface zones. We noted a coincidence between sea-level highstand chronologies in northeastern Brazil and those in the Bahamas and Bermuda.Este estudo apresenta uma investigação de campo e geocronológica realizada ao longo da costa nordeste do Brasil entre ~4°S e 9°S de latitude, o que corresponde a ~700 km de costa submetida a um regime de meso-maré. Nós investigamos terraços marinhos construídos por ondas e datamos sedimentos usando luminescência oticamente estimulada e termoluminescência em grãos de quartzo. Os terraços marinhos forneceram dois grupos de idades: 200-230 ka e 100-130 ka, que interpretamos como idades de deposição. Nós correlacionamos estas idades com idades do estágio isotópico do oxigênio 7c e 5e, respectivamente. Estes eventos correspondem a antepenúltima e penúltima transgressões que ocorreram ao longo da costa brasileira. Os depósitos ocorrem predominantemente em

The Quaternary uplift history of central southern England: evidence from the terraces of the Solent River system and nearby raised beaches

Science.gov (United States)

Westaway, Rob; Bridgland, David; White, Mark

2006-09-01

We have used fluvial (Solent River system) and marine terraces to reconstruct the uplift history of central southern England. In the case of the former, we make the assumption that fluvial incision has been a direct response to surface uplift, with its precise timing controlled by climatic forcing of fluvial activity, such that height of terrace gravel above modern river is a consequence of uplift since deposition. In the case of the marine sequence, we take the height of interglacial raised beaches above a calculated contemporaneous sea-level as a measure of uplift, the calculation involving an adjustment from modern sea-level using the deep oceanic oxygen isotope signal as an indication of global ice volume at the time of deposition. This exercise requires some degree of dating constraint, which is problematic for both environments. The Solent terraces have yielded little biostratigraphical evidence, whereas the south coast raised beaches have either been poorly exposed in recent years or their ages have been controversial because of disputes between biostratigraphy and geochronological data. We have supplemented the evidence available from these sources by using key aspects of the archaeological record as dating constraints, in particular the first appearances of Levallois technique (a marker for MIS 9-8) and of bout coupé handaxes (MIS 3). The first of these has been particularly useful in modelling of the Middle Pleistocene parts of the river terrace staircases of the Solent system. In undertaking this reappraisal, we have noted several inconsistencies and disagreements between past correlation schemes for the terraces of the Solent and its various tributaries. We find that versions involving shallower downstream gradients in the main Solent River are most likely to be correct and that revisions on this basis solve a number of problems in interpretation encountered previously. Our results show that most of this region has uplifted by ˜70 m since the late

Multilocus phylogeny of arvicoline voles (Arvicolini, Rodentia) shows small tree terrace size

Czech Academy of Sciences Publication Activity Database

Martínková, Natália; Moravec, J.

2012-01-01

Roč. 61, 3-4 (2012), s. 254-267 ISSN 0139-7893 R&D Projects: GA AV ČR IAA600930609 Institutional support: RVO:68081766 Keywords : divergence * evolutionary history * supertree * supermatrix * phylogenetic tree terrace * Microtus * Arvicolinae Subject RIV: EG - Zoology Impact factor: 0.494, year: 2012

Controls on dryland mountain landscape development along the NW Saharan desert margin: Insights from Quaternary river terrace sequences (Dadès River, south-central High Atlas, Morocco)

DEFF Research Database (Denmark)

Stokes, M.; Mather, A.E.; Belfoul, M.

2017-01-01

between 50 and 140 m. The rock strength, stratigraphy and structure of the mountain belt influences terrace distribution. Terraces are absent in river gorges of structurally thickened limestone; whilst well-developed, laterally continuous terraces (T1-T4) form along wide valleys occupying syncline...... sands and colluvium. This sequence with some OSL/IRSL age control, suggests terrace formation over a 100 ka climate cycle with valley floor aggradation during full glacials and incision during glacial-interglacial transitions. This integrates with other archives (e.g. lakes, glaciers, dunes), appearing...... typical of landscape development along the NW Saharan margin south of the High Atlas, and similar to patterns in the western-southern Mediterranean. The 100 ka climate cycle relationship suggests that the terrace sequence documents Late-Middle Pleistocene landscape development. Consistent altitudinal...

Topography- and management-mediated resource gradients maintain rare and common plant diversity around paddy terraces.

Science.gov (United States)

Uematsu, Yuta; Ushimaru, Atushi

2013-09-01

Examining the causes of interspecific differences in susceptibility to bidirectional land-use changes (land abandonment and use-intensification) is important for understanding the mechanisms of global biodiversity loss in agricultural landscapes. We tested the hypothesis that rare (endangered) plant species prefer wet and oligotrophic areas within topography- and management-mediated resource (soil water content, nutrient, and aboveground biomass) gradients, making them more susceptible to both abandonment and use-intensification of agricultural lands. We demonstrated that topography and management practices generated resource gradients in seminatural grasslands around traditional paddy terraces. Terraced topography and management practices produced a soil moisture gradient within levees and a nutrient gradient within paddy terraces. Both total and rare species diversity increased with soil water content. Total species diversity increased in more eutrophied areas with low aboveground biomass, whereas rare species diversity was high under oligotrophic conditions. Rare and common species were differentially distributed along the human-induced nutrient gradient, with rare species preferring wet, nutrient-poor environments in the agricultural landscapes studied. We suggest that conservation efforts should concentrate on wet, nutrient-poor areas within such landscapes, which can be located easily using land-use and topography maps. This strategy would reduce the costs of finding and conserving rare grassland species in a given agricultural landscape.

Late Quaternary stream piracy and strath terrace formation along the Belle Fourche and lower Cheyenne Rivers, South Dakota and Wyoming

Science.gov (United States)

Stamm, John F.; Hendricks, Robert R.; Sawyer, J. Foster; Mahan, Shannon A.; Zaprowski, Brent J.; Geibel, Nicholas M.; Azzolini, David C.

2013-09-01

Stream piracy substantially affected the geomorphic evolution of the Missouri River watershed and drainages within, including the Little Missouri, Cheyenne, Belle Fourche, Bad, and White Rivers. The ancestral Cheyenne River eroded headward in an annular pattern around the eastern and southern Black Hills and pirated the headwaters of the ancestral Bad and White Rivers after ~ 660 ka. The headwaters of the ancestral Little Missouri River were pirated by the ancestral Belle Fourche River, a tributary to the Cheyenne River that currently drains much of the northern Black Hills. Optically stimulated luminescence (OSL) dating techniques were used to estimate the timing of this piracy event at ~ 22-21 ka. The geomorphic evolution of the Cheyenne and Belle Fourche Rivers is also expressed by regionally recognized strath terraces that include (from oldest to youngest) the Sturgis, Bear Butte, and Farmingdale terraces. Radiocarbon and OSL dates from fluvial deposits on these terraces indicate incision to the level of the Bear Butte terrace by ~ 63 ka, incision to the level of the Farmingdale terrace at ~ 40 ka, and incision to the level of the modern channel after ~ 12-9 ka. Similar dates of terrace incision have been reported for the Laramie and Wind River Ranges. Hypothesized causes of incision are the onset of colder climate during the middle Wisconsinan and the transition to the full-glacial climate of the late-Wisconsinan/Pinedale glaciation. Incision during the Holocene of the lower Cheyenne River is as much as ~ 80 m and is 3 to 4 times the magnitude of incision at ~ 63 ka and ~ 40 ka. The magnitude of incision during the Holocene might be due to a combined effect of three geomorphic processes acting in concert: glacial isostatic rebound in lower reaches (~ 40 m), a change from glacial to interglacial climate, and adjustments to increased watershed area resulting from piracy of the ancestral headwaters of the Little Missouri River.

The strategies of local farmers' water management and the eco-hydrological effects of irrigation-drainage engineering systems in world heritage of Honghe Hani Rice Terraces

Science.gov (United States)

Gao, Xuan

2017-04-01

Terraces are built in mountainous regions to provide larger area for cultivation,in which the hydrological and geomorphological processes are impacted by local farmers' water management strategies and are modified by manmade irrigation-drainage engineering systems.The Honghe Hani Rice Terraces is a 1300a history of traditional agricultural landscape that was inscribed in the 2013 World Heritage List.The local farmers had developed systematic water management strategies and built perfect irrigation-drainage engineering systems to adapt the local rainfall pattern and rice farming activities.Through field investigation,interviews,combined with Geographic Information Systems,Remote Sensing images and Global Positioning Systems technology,the water management strategies as well as the irrigation-drainage systems and their impacts on eco-hydrological process were studied,the results indicate:Firstly,the local people created and maintained an unique woodcarving allocating management system of irrigating water over hundreds years,which aids distributing water and natural nutrition to each terrace field evenly,and regularly according to cultivation schedule.Secondly,the management of local people play an essential role in effective irrigation-drainage engineering system.A ditch leader takes charge of managing the ditch of their village,keeping ample amount of irrigation water,repairing broken parts of ditches,dealing with unfair water using issues,and so on.Meanwhile,some traditional leaders of minority also take part in.Thus, this traditional way of irrigation-drainage engineering has bringed Hani people around 1300 years of rice harvest for its eco-hydrological effects.Lastly we discuss the future of Honghe Hani Rice Terraces,the traditional cultivation pattern has been influenced by the rapid development of modern civilization,in which some related changes such as the new equipment of county roads and plastic channels and the water overusing by tourism are not totally

Late Quaternary uplift rate inferred from marine terraces, Muroto Peninsula, southwest Japan: Forearc deformation in an oblique subduction zone

Science.gov (United States)

Matsu'ura, Tabito

2015-04-01

Tectonic uplift rates across the Muroto Peninsula, in the southwest Japan forearc (the overriding plate in the southwest Japan oblique subduction zone), were estimated by mapping the elevations of the inner edges of marine terrace surfaces. The uplift rates inferred from marine terraces M1 and M2, which were correlated by tephrochronology with marine isotope stages (MIS) 5e and 5c, respectively, include some vertical offset by local faults but generally decrease northwestward from 1.2-1.6 m ky- 1 on Cape Muroto to 0.3-0.7 m ky- 1 in the Kochi Plain. The vertical deformation of the Muroto Peninsula since MIS 5e and 5c was interpreted as a combination of regional uplift and folding related to the arc-normal offshore Muroto-Misaki fault. A regional uplift rate of 0.46 m ky- 1 was estimated from terraces on the Muroto Peninsula, and the residual deformation of these terraces was attributed to fault-related folding. A mass-balance calculation yielded a shortening rate of 0.71-0.77 m ky- 1 for the Muroto Peninsula, with the Muroto-Misaki fault accounting for 0.60-0.71 m ky- 1, but these rates may be overestimated by as much as 10% given variations of several meters in the elevation difference between the buried shoreline angles and terrace inner edges in the study area. A thrust fault model with flat (5-10° dip) and ramp (60° dip) components is proposed to explain the shortening rate and uplift rate of the Muroto-Misaki fault since MIS 5e. Bedrock deformation also indicates that the northern extension of this fault corresponds to the older Muroto Flexure.

Fluvial terrace formation in the northern Upper Rhine Graben during the last 20 000 years as a result of allogenic controls and autogenic evolution

NARCIS (Netherlands)

Erkens, G.; Dambeck, R.; Volleberg, K.P.; Bouman, M.I.T.J.; Bos, J.A.A.; Cohen, K.M.; Hoek, W.Z.

2009-01-01

The northern Upper Rhine Graben hosts a well-preserved Late Weichselian and Holocene fluvial terrace sequence. Terraces differ in elevation, morphology, and overbank sediment characteristics. The purpose of this study was to determine the relative importance of allogenic controlling factors versus

Timing and nature of alluvial fan and strath terrace formation in the Eastern Precordillera of Argentina

Science.gov (United States)

Hedrick, Kathryn; Owen, Lewis A.; Rockwell, Thomas K.; Meigs, Andrew; Costa, Carlos; Caffee, Marc W.; Masana, Eulalia; Ahumada, Emilio

2013-11-01

Sixty-eight 10Be terrestrial cosmogenic nuclide (TCN) surface exposure ages are presented to define the timing of alluvial fan and strath terrace formation in the hyper-arid San Juan region of the Argentine Precordillera. This region is tectonically active, and numerous fault scarps traverse Quaternary landforms. The three study sites, Marquesado strath complex, Loma Negra alluvial fan and Carpintería strath complex reveal a history of alluvial fan and strath terrace development over the past ˜225 ka. The Marquesado complex Q3m surface dates to ˜17 ± 3 ka, whereas the Loma Negra Q1ln, Q2ln, Q3ln, Q4ln, and Q5ln surfaces date to ˜24 ± 3 ka, ˜48 ± 2 ka, ˜65 ± 13 ka, ˜105 ± 21 ka, and ˜181 ± 29 ka, respectively. The Carpintería complex comprises eight surfaces that have been dated and include the Q1c (˜23 ± 3 ka), Q2c (˜5 ± 5 ka), Q3ac (˜25 ± 12 ka), Q3bc (˜29 ± 15 ka), Q4c (˜61 ± 12 ka), Q5c (˜98 ± 18 ka), Q6c (˜93 ± 18 ka), and Q7c (˜212 ± 37 ka). 10Be TCN depth profile data for the Loma Negra alluvial fan complex and Carpintería strath terrace complex, as well as OSL ages on some Carpintería deposits, aid in refining surface ages for comparison with local and global climate proxies, and additionally offer insights into inheritance and erosion rate values for TCNs (˜10 × 10410Be atoms/g of SiO2 and ˜5 m Ma-1, respectively). Comparison with other alluvial fan studies in the region show that less dynamic and older preserved surfaces occur in the Carpintería and Loma Negra areas with only younger alluvial fan surfaces preserved both to the north and south. These data in combination with that of other studies illustrate broad regional agreement between alluvial fan and strath terrace ages, which suggests that climate is the dominant forcing agent in the timing of terrace formation in this region.

Soils on raised marine terraces in the Metaponto area, S Italy: not a simple chronosequence

Science.gov (United States)

Sauer, Daniela; Al-Sharif, Riyad; Wagner, Stephen; Scarciglia, Fabio; Deffontaines, Benoît; Benvenuti, Marco; Carnicelli, Stefano; Brückner, Helmut

2015-04-01

A sequence of Middle and Late Pleistocene raised marine terraces stretches along the Gulf of Taranto, S Italy, for more than 65 km from Rocca Imperiale, Calabria, in the SW to Taranto, Apulia, in the NE, in an approximately 25 km wide belt. The terraces formed as a result of the interplay between sea-level fluctuations and regional tectonic uplift over a time-span of ca. 780 ka. They were selected for establishing a soil chronosequence, in order to analyse rates of soil-forming processes in the central Mediterranean region. Indeed, several general trends of soil formation with terrace age were identified. For example, soil thickness and Fed/Fet ratios increase, while the weathering ratio (Ca+Mg+K+Na)/Al decreases with assumed terrace age. These changes could be best described by power functions (R2 = 0.88 for soil thickness, R2 = 0.87 for Fed/Fet, and R2 = 0.96 for (Ca+Mg+K+Na)/Al). However, closer examination revealed that the soils did not simply form in the marine gravel bodies but in various kinds of sediments. The development of the landscape along the Gulf of Taranto turned out to be much more complex than previously expected. Sediment-soil successions exposed in several gravel quarries reveal that each terrace, after its original formation, was exposed to changing conditions in terms of climate, vegetation, level of erosion base (related to sea-level oscillations and/or tectonics), and other environmental factors during the Pleistocene and Holocene periods. As a result, it was subject to (i) further geomorphological and sedimentological evolution, including incision, denudation, deposition of alluvial sediments, and accumulation of colluvial deposits, in parts due to natural processes and in parts due to human activity; (ii) various directions and rates of soil development, corresponding to changing environmental conditions during glacial and interglacial periods. In some cases, there is evidence for a period of soil formation in the marine deposits prior to

Quaternary river incision in the uplifted Rhenish massif (Ardennes, Belgium) - Insights from 10Be/26Al dating of river terraces

Science.gov (United States)

Rixhon, Gilles; Bourlès, Didier; Braucher, Régis; Siame, Lionel; Bovy, Benoît.; Demoulin, Alain

2010-05-01

Although it constitutes the main tool to unravel the regional recent tectonics, the chronology of the Pleistocene river incision is still poorly constrained within the uplifted Rhenish-Ardennes massif (Belgium, western Europe). Here, we measure cosmogenic nuclides concentrations (10Be and 26Al) in terrace quartz or quartzite sediments of several Ardennian rivers (Meuse, Ourthe and Amblève) in order to date the so-called Younger Main Terrace (YMT), a key-level in the network evolution. Though these dating methods are successfully used to determine ages of superficial (e.g., glacial) deposits, dating of fluvial terraces remains difficult. Possible predepositional exposures of the sampled material (inherited 10Be and 26Al) may indeed bias the measurements towards higher nuclide concentrations while several postdepositional processes (burial, erosion) may cause a lowering of the 10Be and 26Al concentrations. In an attempt to overcome these difficulties, the selected fluvial deposits (five locations) were sampled using a profiling technique on as thick as possible sections (more than 3 m). We present the first absolute dating of the YMT in the lower Meuse valley (nearby the Dutch boundary), where we obtained an age of 630 ka for a terrace deposit buried beneath 3 m of Weichselian loess. This age is consistent with some previously published estimates based on paleomagnetic data and MIS correlations. However, our ages for the same terrace level within the Ardennes are significantly younger: >400 ka in the lower Ourthe, and only ~220 ka still farther upstream, in the lower Amblève. We thus demonstrate that the post-YMT incision occurred diachronically in NE Ardennes. The ~0.5 Ma timespan needed by the erosion wave to propagate from the lower Meuse towards the Ardennian headwaters contradicts the long-held statement of a climatically driven incision that would have been synchronous throughout the catchment.

Post-tectonic landscape evolution in NE Iberia using staircase terraces: Combined effects of uplift and climate

Science.gov (United States)

Lewis, Claudia J.; Sancho, Carlos; McDonald, Eric V.; Peña-Monné, José Luis; Pueyo, Emilio L.; Rhodes, Edward; Calle, Mikel; Soto, Ruth

2017-09-01

River incision into bedrock resulting from the combined effects of tectonic uplift and climate governs long-term regional landscape evolution. We determined spatial and temporal patterns of post-orogenic stream incision from a sequence of well-preserved staircase terraces developed over the last 1 Ma in the Central Pyrenees and its southern foreland Ebro basin (NE Spain). Extensive remnants of ten vertically separated terraces (Qt1 to Qt10, from oldest to youngest) were mapped along 170 km of the Cinca River valley, transverse to the Pyrenean mountain belt. Multiple outcrops appear in the upper reach of the valley (Ainsa sector, 50 km from headwaters) as well as in the lower reach (Albalate sector, 125 km from headwaters). Fluvial incision into bedrock was calculated using (i) differentially corrected GPS measurements of the altitude of straths and (ii) numerical dating of alluvial sediments from the lower terraces (Qt5 to Qt9) by Optically Stimulated Luminescence, previously reported by Lewis et al. (2009), and supplemented with new dates for the upper terraces (Qt1, Qt2 and Qt3) based on paleomagnetism and supported by soil development. Considering altitude differences and the elapsed time between successive well preserved terrace couples (Qt3-Qt7, Qt7-Qt9 and Qt9-Active channel), mean bedrock incision rates ranged from 0.76 to 0.38 m ka- 1, at the upper reach of the valley (Ainsa section), and from 0.61 to 0.20 m ka- 1, at the lower reach (Albalate section). River incision along the valley produced vertically separated, near-parallel longitudinal terrace profiles evidencing a rapid near-uniform regional uplift as response to (i) the tectonic lithospheric thickening in NE Iberia and (ii) the erosional download rebound related to the Ebro basin exorheism. Moreover, a subtle upstream divergence of strath profiles may have been a consequence of an increase in uplift rate toward the head of the valley. Additionally, incision rates changed over time as indicate

Characterization of seven United States coal regions. The development of optimal terrace pit coal mining systems

Energy Technology Data Exchange (ETDEWEB)

Wimer, R.L.; Adams, M.A.; Jurich, D.M.

1981-02-01

This report characterizes seven United State coal regions in the Northern Great Plains, Rocky Mountain, Interior, and Gulf Coast coal provinces. Descriptions include those of the Fort Union, Powder River, Green River, Four Corners, Lower Missouri, Illinois Basin, and Texas Gulf coal resource regions. The resource characterizations describe geologic, geographic, hydrologic, environmental and climatological conditions of each region, coal ranks and qualities, extent of reserves, reclamation requirements, and current mining activities. The report was compiled as a basis for the development of hypothetical coal mining situations for comparison of conventional and terrace pit surface mining methods, under contract to the Department of Energy, Contract No. DE-AC01-79ET10023, entitled The Development of Optimal Terrace Pit Coal Mining Systems.

Unraveling the Quaternary river incision in the Moselle valley (Rhenish Massif, Germany): new insights from cosmogenic nuclide dating (10Be/26Al) of the Main Terrace complex

Science.gov (United States)

Rixhon, Gilles; Cordier, Stéphane; Harmand, Dominique; May, Simon Matthias; Kelterbaum, Daniel; Dunai, Tibor; Binnie, Steven; Brückner, Helmut

2014-05-01

Throughout the whole river network of the Rhenish Massif, the terrace complex of the so-called Main Terrace forms the morphological transition between a wide upper palaeovalley (plateau valley) and a deeply incised lower valley. The youngest level of this Main Terrace complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature in the terrace flight; it is often used as a reference level to identify the start of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). The latter probably reflects the major tectonic pulse that affected the whole Massif and was related to an acceleration of the uplift rates (Demoulin & Hallot, 2009). The Main terraces are particularly well preserved in the lower Moselle valley and are characterized by a constant absolute elevation of their base along a 150 km-long reach. Despite that various hypotheses have been proposed to explain this horizontality (updoming, faulting...), all studies assumed an age of ca. 800 ka for the YMT, mainly based on the questionable extrapolation of palaeomagnetic data obtained in the Rhine valley. Therefore, a reliable chronological framework is still required to unravel the spatio-temporal characteristics of the Pleistocene evolution of the Moselle valley. In this study, we apply cosmogenic nuclide dating (10Be/26Al) to fluvial sediments pertaining to the Main Terrace complex or to the upper Middle Terraces. Several sites along the lower Moselle were sampled following two distinct sampling strategies: (i) depth profiles where the original terrace (palaeo-)surface is well preserved and did not experience much postdepositional burial (e.g., loess cover); and (ii) the isochron technique where the sediment thickness exceeds 3 m. Cosmogenic nuclide ages recently obtained for three rivers in the Meuse catchment in the western Rhenish Massif demonstrated that the Main Terraces were younger than expected and their abandonment was diachronic along the

Step dynamics and terrace-width distribution on flame-annealed gold films: The effect of step-step interaction

International Nuclear Information System (INIS)

Shimoni, Nira; Ayal, Shai; Millo, Oded

2000-01-01

Dynamics of atomic steps and the terrace-width distribution within step bunches on flame-annealed gold films are studied using scanning tunneling microscopy. The distribution is narrower than commonly observed for vicinal planes and has a Gaussian shape, indicating a short-range repulsive interaction between the steps, with an apparently large interaction constant. The dynamics of the atomic steps, on the other hand, appear to be influenced, in addition to these short-range interactions, also by a longer-range attraction of steps towards step bunches. Both types of interactions promote self-ordering of terrace structures on the surface. When current is driven through the films a step-fingering instability sets in, reminiscent of the Bales-Zangwill instability

The impact of episodic fault-related folding on Late Holocene degradation terraces along Waipara River, New Zealand

International Nuclear Information System (INIS)

Nicol, A.; Campbell, J.K.

2001-01-01

The Waipara River flows eastwards through growing folds in the tectonically active foothills of New Zealand's Southern Alps. In the middle Waipara region, flights of degradation terraces are widespread and rise to 55 m above river channels. Ages of terrace surfaces and paleoearthquakes on four faults are constrained by radiocarbon samples and weathering-rind dates from surface cobbles of Torlesse Group sandstone. Terrace ages indicate rapid incision (c. 30-100 mm/yr) of Waipara River and three tributaries during the Late Holocene. Cumulative-incision curves suggest a 15-25 m lowering of regional base level over the last thousand years and an additional 20-25 m of local incision 200-600 yr BP along Waipara River where it crosses Doctors Anticline. Rapid river incision was strongly influenced by rock uplift on the anticline associated with fault rupture during an earthquake 300-400 yr BP. From incision data we infer that the earthquake was preceded and followed by aseismic fold growth. Tectonic uplift during folding was probably, at most, one-third of local river incision; this discrepancy may relate to the short sample period and to locally elevated stream erosive power due in part to a reduction in floodplain width. (author). 41 refs., 12 figs., 2 tabs

Uplift rates of marine terraces as a constraint on fault-propagation fold kinematics: Examples from the Hawkswood and Kate anticlines, North Canterbury, New Zealand

Science.gov (United States)

Oakley, David O. S.; Fisher, Donald M.; Gardner, Thomas W.; Stewart, Mary Kate

2018-01-01

Marine terraces on growing fault-propagation folds provide valuable insight into the relationship between fold kinematics and uplift rates, providing a means to distinguish among otherwise non-unique kinematic model solutions. Here, we investigate this relationship at two locations in North Canterbury, New Zealand: the Kate anticline and Haumuri Bluff, at the northern end of the Hawkswood anticline. At both locations, we calculate uplift rates of previously dated marine terraces, using DGPS surveys to estimate terrace inner edge elevations. We then use Markov chain Monte Carlo methods to fit fault-propagation fold kinematic models to structural geologic data, and we incorporate marine terrace uplift into the models as an additional constraint. At Haumuri Bluff, we find that marine terraces, when restored to originally horizontal surfaces, can help to eliminate certain trishear models that would fit the geologic data alone. At Kate anticline, we compare uplift rates at different structural positions and find that the spatial pattern of uplift rates is more consistent with trishear than with a parallel-fault propagation fold kink-band model. Finally, we use our model results to compute new estimates for fault slip rates ( 1-2 m/ka at Kate anticline and 1-4 m/ka at Haumuri Bluff) and ages of the folds ( 1 Ma), which are consistent with previous estimates for the onset of folding in this region. These results are consistent with previous work on the age of onset of folding in this region, provide revised estimates of fault slip rates necessary to understand the seismic hazard posed by these faults, and demonstrate the value of incorporating marine terraces in inverse fold kinematic models as a means to distinguish among non-unique solutions.

Do Knickpoints Unzip Watersheds? Longitudinal Observations of Terrace and Hillslope Response to Mainstem Incision along the South Fork Eel River, California

Science.gov (United States)

Wehrs, K.; Crosby, B. T.

2017-12-01

River response to changes in climate and relative base level often leave behind a legacy of transient landforms that enable the interpretation of past events. The dominant paradigm is that base level fall initiates a wave of mainstem incision that progressively transmits change upstream. Mainstem-adjacent hillslopes coupled to the channel subsequently respond as their toe slopes are steepened. To test this paradigm, we first use a longitudinal set of mainstem terrace ages to evaluate whether incision incrementally progresses upstream or is contemporaneous. Second, we explore longitudinal variations in mainstem-adjacent mass movements to evaluate whether they reflect a time and space progression in response. The South Fork Eel River in northern California contains over 600 mainstem-adjacent mass movements and 60 m tall, longitudinally extensive strath terraces that record a landscape response to river incision. We use Optically Stimulated Luminescence, with feldspars and coarse-grained sampling technique, to determine the depositional age of alluvial fill atop the strath terrace. If terrace abandonment progressively young upstream, this suggests that base level fall was not spatially contemporaneous, but rather time progressive. As a consequence, the age, form, and extent of mass wasting events should also vary longitudinally. Because terraces isolate hillslopes from the base level fall signal, we use these surfaces to quantify hillslope form and function independent of that forcing. Preliminary results using mainstem-parallel, 1 m LiDAR, show significant variation in size of mass movements throughout the basin, with planar, linearly moving translational landslides dominating throughout the catchment. In the lower basin, well downstream of the current knickzone, we see an increase in mass movement concentration, reactivation, and overall extent of mass movements. Multiple factors confound our interpretation of hillslope morphology and response, due to changes in

Resilience and adaptability of rice terrace social-ecological systems: a case study of a local community's perception in Banaue, Philippines

Directory of Open Access Journals (Sweden)

Adam C. Castonguay

2016-06-01

Full Text Available The social-ecological systems of rice terraces across Southeast Asia are the result of centuries of long-term interactions between human communities and their surrounding ecosystems. Processes and structures in these systems have evolved to provide a diversity of ecosystem services and benefits to human societies. However, as Southeast Asian countries experience rapid economic growth and related land-use changes, the remaining extensive rice cultivation systems are increasingly under pressure. We investigated the long-term development of ecosystem services and the adaptive capacity of the social-ecological system of rice terrace landscapes using a case study of Banaue (Ifugao Province, Northern-Luzon, Philippines. A set of indicators was used to describe and assess changes in the social-ecological state of the study system. The resilience of the rice terraces and the human communities that maintain them was examined by comparing the current state of the system with results from the literature. Our findings indicate that, although the social-ecological system has not yet shifted to an alternative state, pressures are increasing and some cultural ecosystem services have already been lost.

Implications from Sedimentary records in Fluvial Terraces for Geomorphological Evolution in the Puli Basin, Taiwan

NARCIS (Netherlands)

Tseng, C.H.; Wenske, D.; Böse, M.; Reimann, T.; Lüthgens, C.; Frechen, Manfred

2013-01-01

Fluvial terraces play an important role for research on previous geomorphic processes as their sediments can record various sedimentation stages. In the mountains of central Taiwan, however, the formation time of sediments in the Puli Basin is still unclear. In this study, we investigate the fluvial

Properties of anthropogenic soils in ancient run-off capturing agricultural terraces in the Central Negev desert (Israel) and related effects of biochar and ash on crop growth

NARCIS (Netherlands)

Asperen, van H.L.; Bor, A.M.C.; Sonneveld, M.P.W.; Bruins, H.J.; Lazarovitch, N.

2014-01-01

In the Central Negev hills (Israel) many ancient terraced wadis exist, which captured run-off and caused gradual soil aggradation, which enabled agricultural practices. In these terraces, dark colored soil horizons were observed, containing charcoal, as can be found in Terra Preta soils, suggesting

Reconstructing the interacting effects of base level, climate, and tectonic uplift in the lower Miño River terrace record: A gradient modelling evaluation/ March 2013

NARCIS (Netherlands)

Viveen, W.; Schoorl, J.M.; Veldkamp, A.; Balen, van R.T.; Desprat, S.; Vidal-Romani, J.R.

2013-01-01

The origin of the lower Miño River terraces in the NW Iberian Peninsula has been a topic of debate since the 1940s. Various hypotheses about their main controlling factors have been put forward, but general consensus is still lacking. Field studies of terrace distribution and the weathering of

Deformed Fluvial Terraces of Little Rock Creek Capture Off-Fault Strain Adjacent to the Mojave Section of the San Andreas Fault

Science.gov (United States)

Moulin, A.; Scharer, K. M.; Cowgill, E.

2017-12-01

Examining discrepancies between geodetic and geomorphic slip-rates along major strike-slip faults is essential for understanding both fault behavior and seismic hazard. Recent work on major strike-slip faults has highlighted off-fault deformation and its potential impact on fault slip rates. However, the extent of off-fault deformation along the San Andreas Fault (SAF) remains largely uncharacterized. Along the Mojave section of the SAF, Little Rock Creek drains from south to north across the fault and has cut into alluvial terraces abandoned between 15 and 30 ka1. The surfaces offer a rare opportunity to both characterize how right-lateral slip has accumulated along the SAF over hundreds of seismic cycles, and investigate potential off-fault deformation along secondary structures, where strain accumulates at slower rates. Here we use both field observations and DEM analysis of B4 lidar data to map alluvial and tectonic features, including 9 terrace treads that stand up to 80 m above the modern channel. We interpret the abandonment and preservation of the fluvial terraces to result from episodic capture of Little Rock Creek through gaps in a shutter ridge north of the fault, followed by progressive right deflection of the river course during dextral slip along the SAF. Piercing lines defined by fluvial terrace risers suggest that the amount of right slip since riser formation ranges from 400m for the 15-ka-riser to 1200m for the 30-ka-riser. Where they are best-preserved NE of the SAF, terraces are also cut by NE-facing scarps that trend parallel to the SAF in a zone extending up to 2km from the main fault. Exposures indicate these are fault scarps, with both reverse and normal stratigraphic separation. Geomorphic mapping reveals deflections of both channel and terrace risers (up to 20m) along some of those faults suggesting they could have accommodated a component of right-lateral slip. We estimated the maximum total amount of strike-slip motion recorded by the

Impact of land-use change on soil degradation by establishment of terraces with subtropical orchards in sloping areas (Granada, SE Spain)

International Nuclear Information System (INIS)

Rodriguez Pleguezuelo, C. R.; Duran Zuzo, V. H.; Martin Peinado, F. J.; Franco Tarifa, D.

2009-01-01

In the coast of Granada, an intensive irrigated agriculture based on subtropical crops has been established. These trees have been planted in highly sloped areas, by the construction of terraces. In this fragile Mediterranean agroecosystem, the removal of native spontaneous vegetation cover and substitution by orchards, increase the susceptibility to soil degradation and eventually brings up the destruction of these structures by rainfall events. To study this net change, we monitored the soil loss and runoff over a two-year period in the taluses of terraces with a mature mango (Mangifera indica L.) orchard. The studied treatments were bare soil (BS) and spontaneous vegetation (NSV), each twice replicated. The erosion plots were 4 m x 4 m in area and were located in the taluses of orchard in the taluses of orchard terraces (65 degree centigrade slope). The average annual soil loss by erosion for BS and NSV was 2.5 and 0.3 Mg ha - 1 yr - 1, and for runoff 34.1 and 6.8 mm yr - 1, respectively. Therefore, soil erosion and runoff from BS plot were 8- and 5-times higher than in NSV, showing the importance of plant covers in the taluses of terraces in reducing this impact. Thus, the removal of plant cover from the taluses under these conditions, represent a high risk of slump and collapse, causing serious environmental and economic problems for farmers of subtropical crops. (Author) 11 refs.

Impact of land-use change on soil degradation by establishment of terraces with subtropical orchards in sloping areas (Granada, SE Spain)

Energy Technology Data Exchange (ETDEWEB)

Rodriguez Pleguezuelo, C. R.; Duran Zuzo, V. H.; Martin Peinado, F. J.; Franco Tarifa, D.

2009-07-01

In the coast of Granada, an intensive irrigated agriculture based on subtropical crops has been established. These trees have been planted in highly sloped areas, by the construction of terraces. In this fragile Mediterranean agroecosystem, the removal of native spontaneous vegetation cover and substitution by orchards, increase the susceptibility to soil degradation and eventually brings up the destruction of these structures by rainfall events. To study this net change, we monitored the soil loss and runoff over a two-year period in the taluses of terraces with a mature mango (Mangifera indica L.) orchard. The studied treatments were bare soil (BS) and spontaneous vegetation (NSV), each twice replicated. The erosion plots were 4 m x 4 m in area and were located in the taluses of orchard in the taluses of orchard terraces (65 degree centigrade slope). The average annual soil loss by erosion for BS and NSV was 2.5 and 0.3 Mg ha{sup -}1 yr{sup -}1, and for runoff 34.1 and 6.8 mm yr{sup -}1, respectively. Therefore, soil erosion and runoff from BS plot were 8- and 5-times higher than in NSV, showing the importance of plant covers in the taluses of terraces in reducing this impact. Thus, the removal of plant cover from the taluses under these conditions, represent a high risk of slump and collapse, causing serious environmental and economic problems for farmers of subtropical crops. (Author) 11 refs.

Sixth-Year Results Following Partial Cutting For Timber and Wildlife Habitat in a Mixed Oak-Sweetgum-Pine Stand on a Minor Creek Terrace in Southeast Louisiana

Science.gov (United States)

Brian Roy Lockhart; Norwin E. Linnartz

2002-01-01

Hardwood management has primarily focused on highly productive river bottom and upland sites. Less is known about hardwood growth and development on terrace sites. Such sites are usually converted to other uses, especially pine plantations. The objectives of this study, implemented in a minor creek terrace in southeast Louisiana, were to describe changes in stand...

Flora, life form characteristics, and plan for the promotion of biodiversity in South Korea's Globally Important Agricultural Heritage System, the traditional Gudeuljang irrigated rice terraces in Cheongsando

Institute of Scientific and Technical Information of China (English)

Hong Chul PARK; Choong Hyeon OH

2017-01-01

The objectives of this study were to analyze the biodiversity of the Traditional Gudeuljang Irrigated Rice Terraces in Cheongsando,South Korea's representative GIAHS (Globally Important Agricultural Heritage System) site,with reference to position and land-use features,and to develop a plan to promote agricultural biodiversity in the region.We confirmed approximately 54,000 m2 of Gudeuljang paddy fields by an on-site survey.Of the Traditional Gudeuljang Irrigated Rice Terraces confirmed by onsite inspection,our survey showed that approximately 24,000 m2 are currently being used as paddy fields,approximately 15,000 m2 are being used as dry fields,and approximately 14,000 m2 are fallow.In terms of other non-agricultural land use,there was grassland,including graveyards;artificial arboreal land,such as orchards,rivers and wetlands,and man-made facilities,such as roads and residences.We also confirmed that the Traditional Gudeuljang Irrigated Rice Terraces had higher plant species diversity than conventional terraced rice paddies,and there was a difference in life form characteristics between the two types.Although the superficial topsoil structure is the same for the Traditional Gudeuljang Irrigated Rice Terraces (TGIRTs) and conventional terraced rice paddies,it is thought that the differences in the subsurface structure of the TGIRTs contribute greatly to species and habitat diversity.However,the TGIRTs in Cheongsando are facing degeneration,due to damage and reduction in agricultural activity.The main cause is the reduction in the number of farming households due to an aging population in Cheongsando.In order to address this problem,we proposed a management plan,related to fallow paddy fields in South Korea,to initiate voluntary activities in the TGIRTs.

Heavy Metal Content in Terraced Rice Fields at Sruwen Tengaran Semarang - Indonesia

Science.gov (United States)

Hindarwati, Yulis; Soeprobowati, Tri Retnaningsih; Sudarno

2018-02-01

The presence of heavy metal on agricultural soils can be caused not only natural factors but also due to human intervention. Differences in management and lack of understanding of farmers in the production input of fertilizers and pesticides ensued in land ravaged. Periodic testing of paddy fields is necessary to minimize the contaminants from being absorbed by plants that will have an impact on health decline. The purpose of the assessment was to identify the heavy metal content in the terraced rice field in Sruwen Village, Tengaran District, Semarang Regency. Survey was conducted in February 2017. Sampling on terraced rice fields of different heights consisted of upper, middle, and upper down. Taken as many as eight single points and composed at a depth of 0-20 cm and 20-40 cm. The identification results showed that heavy metal content of Pb, Cd, and Cu were present at all altitudes. Heavy Metals Pb and Cd at a depth of 0-20 cm were higher from 20-40 cm in the upper and lower rice fields but lower in the middle rice field. Cu heavy metal at a depth of 0-20 cm was higher than 20-40 cm in all altitude land. The heavy metal content of Pb, Cd, and Cu was still below the heavy metal standard set by the European Union and India.

How to model the stability of terraced slopes? The case study of Tresenda (northern Italy)

Science.gov (United States)

Camera, Corrado; Apuani, Tiziana; Masetti, Marco

2015-04-01

Terraces are very common morphological features all around the Mediterranean Basin. They have been built to adapt the natural morphology of the territory to the development of anthropogenic activities, particularly agriculture. However, the increasing land abandonment during the last century is leading to soil degradation and stability issues, mainly due to lack of maintenance of these peculiar environments. The objective of this study was to develop a coupled hydrologic-stability model to identify possible triggering areas of superficial landslides during intense rainfall events. The model was tested on a slope uphill of the village of Tresenda, in Northern Italy, which experienced several superficial landslides in the last 35 years. Distributed stability analyses are usually carried out using an infinite slope approach, but in the case of terraces some basic assumptions of this method fail: the parallelism between topographical surface and potential sliding surface and the high ratio between slope length and failure surface depth are the most important examples. In addition, the interest is more on the stability of the terrace system (dry stone retaining wall and backfill soil) and not on soil alone. For these reasons, a stability analysis based on the global method of equilibrium is applied and soft coupled to a well know hydrological model (STARWARS). Sections of terrace, one cell wide, are recognized from the base of a wall to the top of the closest downstream one, and each cell (1 x 1 m2) is considered as a slice. The method of Sarma for circular and non-circular failure is applied. The very fine horizontal resolution (1 m) is crucial to take into consideration the hydrogeological and mechanical properties of dry stone walls (0.6-1.0 m wide). A sensitivity analysis was conducted for saturated water content, initial volumetric water content, the cohesion and friction angle of soil and walls and soil depth. The results of the sensitivity analysis showed that

Why most agricultural terraces in steep slopes in semiarid SE Spain remain well preserved since their abandonment 50 years go?

Directory of Open Access Journals (Sweden)

Cantón, F.

2010-12-01

Full Text Available A large part of the agricultural terraces in mountain environments are abandoned, like those from the Filabres range in Almería, SE Spain. While many of such terraces show signs of soil erosion (wall disruptions, surface crusts, pipes and gullies, others in steep slopes remain well preserved after 50 years since their abandonment and still seem to play an active role against soil erosion. In order to know both magnitude of soil erosion and controlling factors in different types of abandoned terraces, a rainfall simulation campaign with a portable sprinkler was carried out in 45 representative microsites. Runoff, derived-infiltration and sediment production were measured and their relationships to basic soil parameters (particle size distribution, pH, EC, organic matter content, aggregate stability, geomorphic position, and ground cover, were examined. Under the average applied rainfall intensity (48 mm/h, which represents a precipitation with a return period of 5 years in the area, narrow bench terraces from steep hillslopes, have larger infiltration values and deliver less sediments than large bank terraces in alluvial plains. The presence of stony pavement sieving crusts on narrow-bench terraces and also on un-terraced alluvial fans, play an essential armouring effect against soil erosion while favouring water infiltration. Considerations are made about the evolution of the different types of traditional terraces in the area under both past agricultural and present abandoned status, and also about possible uses under a sustainable land management policy.

Una gran parte de las terrazas agrícolas en zonas de montaña están abandonadas, como las de la Sierra de los Filabres en Almería, SE de España. Si bien muchas de dichas terrazas muestran señales de erosión hídrica (destrucción de muros, encostramiento superficial, piping y cárcavas, otras en laderas con pendientes acusadas siguen bien conservadas tras 50 años de abandono y

Holocene submarine terraces on the western continental shelf of India; implications for sea-level changes

Digital Repository Service at National Institute of Oceanography (India)

Wagle, B.G.; Vora, K.H.; Karisiddaiah, S.M.; Veerayya, M.; Almeida, F.

and the shelf break, being more common between 11~' and 20~'N. The terraces are prominent between water depths of 50 and 115 m and occur at six distinct levels: (1) 55-60 m, (2) 65-70 m, (3) 75-80 m, (4) 85-90 m, (5) 95-100 m and (6) 110-115 m...

Active folding of fluvial terraces across a `blind' Himalayan deformation front in the Kashmir Himalaya, northwest India.

Science.gov (United States)

Gavillot, Y. G.; Meigs, A.; Rittenour, T. M.; Malik, M. O. A.

2016-12-01

In Kashmir, the Himalayan Frontal thrust (HFT) is blind, characterized by a broad fold, the Suruin-Mastargh anticline, and displays no emergent faults cutting either limb. A lack of knowledge of the rate of shortening and structural framework of the Suruin-Mastargh anticline hampers quantifying the earthquake potential for the deformation front. Our study utilized the geomorphic expression of dated deformed terraces on the Ujh River in Kashmir. Six terraces are recognized, and four yield multiple optically stimulated luminescence (OSL) and depth profiles terrigenous cosmogenic nuclides (TCN) ages between 53 ka and 0.4 ka. Vector fold restoration of long terrace profiles indicates a deformation pattern characterized by regional uplift across the anticlinal axis and back-limb, and by fold limb rotation on the forelimb. Differential uplift across the fold trace suggests localized deformation. Dip data and stratigraphic thicknesses suggest that a duplex structure is emplaced at depth along the basal décollement, folding the overlying roof thrust and Siwalik-Murree strata into a detachment-like fold. Localized faulting at the fold axis explains the asymmetrical fold geometry. Folding of the oldest dated terrace, suggests rock uplift rates across the Suruin-Mastargh anticline range between 1.8-2.5 mm/yr. Assuming a 25° dipping ramp for the blind structure on the basis of dip data constraints, the shortening rates across the Suruin-Mastargh anticline range between 3.8-5.4 mm/yr since 53 ka. Geodetic data indicate that an 11-12 mm/yr arc-normal shortening rate characterizes the interseismic strain accumulation across the plate boundary due to India-Tibet convergence. These data combined with rates of other active internal faults in the Kashmir Himalaya indicate that the Riasi fault accounts for the remainder 60% of the convergence not taken up by the Suruin-Mastargh anticline. We attribute a non-emergent thrust at the deformation front to reflect deformation controlled

Environmental factors influencing the distribution of agricultural terraces: Case study of Horny Tisovnik, Slovakia

Czech Academy of Sciences Publication Activity Database

Slámová, M.; Krčmářová, Jana; Hrončiek, P.; Kaštierová, M.

2017-01-01

Roč. 25, č. 1 (2017), s. 34-45 ISSN 1210-8812 R&D Projects: GA ČR(CZ) GA16-15716S Institutional support: RVO:68378076 Keywords : agricultural terraces * traditional landscapes * environmental history * multivariate analysis * Slovakia Subject RIV: AC - Archeology, Anthropology, Ethnology OBOR OECD: Cultural and economic geography Impact factor: 2.149, year: 2016 http://www.geonika.cz/EN/research/ENMGRClanky/2017_1_SLAMOVA.pdf

Sea-level history and tectonic uplift during the last-interglacial period (LIG): Inferred from the Bab al-Mandab coral reef terraces, southern Red Sea

Science.gov (United States)

Al-Mikhlafi, Ahmed Saif; Edwards, Lawrence R.; Cheng, Hai

2018-02-01

Results of U-series dating of late Pleistocene raised coral reef terraces from the Bab al-Mandab area, define two distinct groups: (1) well-preserved aragonitic fossil corals recorded from the Al-Hajaja terrace (Tr3) yield ages for last-interglacial period (LIG); and (2) calcitic fossil corals recovered from Perim Island terrace (Tr1) show varying degrees of U-series open system behavior and yield coral assemblage ages of LIG and older ages. Fossil corals from Tr1 are recrystallized corals, have anomalously high initial δ234U ranged from (152 ± 2‰ to 287 ± 7‰), corresponding to ages of ∼120 ka and ∼406 ka, respectively. Applying age reliability criteria on the current data suggest majority of the ages cannot be considered reliable and all are suspected for open system behavior associated with U loss/addition that significantly affects the 230Th/U ages. The diagenesis shown by these corals occurred probably due to extensive interaction of fossil corals with freshwater during the wet periods prevailed in southern Arabia coeval with the African monsoon, which led to U loss. Post-depositional U loss suggest (230Th/238U) increase, which shift the U-Th ages to unexpectedly higher levels as it is shown here. Measured elevation at the Al-Hajaja terrace (Tr3) is ∼4 ± 2 m above present sea level (apsl) consistent with eustatic sea level changes and indicates that the Bab al-Mandab area is stable at least since the LIG period. The Perim Island terrace (Tr1) is at elevation of 7 ± 2 m apsl; its reef yields diageneticaly-altered corals of multiple ages and cannot be used for sea level reconstructions.

Faulted terrace risers place new constraints on the late Quaternary slip rate for the central Altyn Tagh fault, northwest Tibet

Science.gov (United States)

Gold, R.D.; Cowgill, E.; Arrowsmith, J.R.; Chen, X.; Sharp, W.D.; Cooper, K.M.; Wang, X.-F.

2011-01-01

The active, left-lateral Altyn Tagh fault defines the northwestern margin of the Tibetan Plateau in western China. To clarify late Quaternary temporal and spatial variations in slip rate along the central portion of this fault system (85??-90??E), we have more than doubled the number of dated offset markers along the central Altyn Tagh fault. In particular, we determined offset-age relations for seven left-laterally faulted terrace risers at three sites (Kelutelage, Yukuang, and Keke Qiapu) spanning a 140-km-long fault reach by integrating surficial geologic mapping, topographic surveys (total station and tripod-light detection and ranging [T-LiDAR]), and geochronology (radiocarbon dating of organic samples, 230Th/U dating of pedogenic carbonate coatings on buried clasts, and terrestrial cosmogenic radionuclide exposure age dating applied to quartz-rich gravels). At Kelutelage, which is the westernmost site (37.72??N, 86.67??E), two faulted terrace risers are offset 58 ?? 3 m and 48 ?? 4 m, and formed at 6.2-6.1 ka and 5.9-3.7 ka, respectively. At the Yukuang site (38.00??N, 87.87??E), four faulted terrace risers are offset 92 ?? 12 m, 68 ?? 6 m, 55 ?? 13 m, and 59 ?? 9 m and formed at 24.2-9.5 ka, 6.4-5.0 ka, 5.1-3.9 ka, and 24.2-6.4 ka, respectively. At the easternmost site, Keke Qiapu (38.08??N, 88.12??E), a faulted terrace riser is offset 33 ?? 6 m and has an age of 17.1-2.2 ka. The displacement-age relationships derived from these markers can be satisfied by an approximately uniform slip rate of 8-12 mm/yr. However, additional analysis is required to test how much temporal variability in slip rate is permitted by this data set. ?? 2011 Geological Society of America.

Socioeconomic Dimensions of Changes in the Agricultural Landscape of the Mediterranean Basin: A Case Study of the Abandonment of Cultivation Terraces on Nisyros Island, Greece

Science.gov (United States)

Petanidou, Theodora; Kizos, Thanasis; Soulakellis, Nikolaos

2008-02-01

Agricultural landscapes illustrate the impact of human actions on physical settings, and differential human pressures cause these landscapes to change with time. Our study explored changes in the terraced landscapes of Nisyros Island, Greece, focusing on the socioeconomic aspects during two time periods using field data, cadastral research, local documents, and published literature, as well as surveys of the islanders. Population increases during the late 19th to early 20th centuries marked a significant escalation of terrace and dry stone wall construction, which facilitated cultivation on 58.4% of the island. By the mid-20th century, the economic collapse of agricultural activities and consequent emigration caused the abandonment of cultivated land and traditional management practices, dramatically reducing farm and field numbers. Terrace abandonment continued in recent decades, with increased livestock grazing becoming the main land management tool; as a result, both farm and pasture sizes increased. Neglect and changing land use has led to deterioration and destruction of many terraces on the island. We discuss the socioeconomic and political backgrounds responsible for the land-use change before World War II (annexation of Nisyros Island by the Ottoman Empire, Italy, and Greece; overseas migration opportunities; and world transportation changes) and after the war (social changes in peasant societies; worldwide changes in agricultural production practices). The adverse landscape changes documented for Nisyros Island appear to be inevitable for modern Mediterranean rural societies, including those on other islands in this region. The island’s unique terraced landscapes may qualify Nisyros to become an archive or repository of old agricultural management techniques to be used by future generations and a living resource for sustainable management.

Socioeconomic dimensions of changes in the agricultural landscape of the Mediterranean basin: a case study of the abandonment of cultivation terraces on Nisyros Island, Greece.

Science.gov (United States)

Petanidou, Theodora; Kizos, Thanasis; Soulakellis, Nikolaos

2008-02-01

Agricultural landscapes illustrate the impact of human actions on physical settings, and differential human pressures cause these landscapes to change with time. Our study explored changes in the terraced landscapes of Nisyros Island, Greece, focusing on the socioeconomic aspects during two time periods using field data, cadastral research, local documents, and published literature, as well as surveys of the islanders. Population increases during the late 19th to early 20th centuries marked a significant escalation of terrace and dry stone wall construction, which facilitated cultivation on 58.4% of the island. By the mid-20th century, the economic collapse of agricultural activities and consequent emigration caused the abandonment of cultivated land and traditional management practices, dramatically reducing farm and field numbers. Terrace abandonment continued in recent decades, with increased livestock grazing becoming the main land management tool; as a result, both farm and pasture sizes increased. Neglect and changing land use has led to deterioration and destruction of many terraces on the island. We discuss the socioeconomic and political backgrounds responsible for the land-use change before World War II (annexation of Nisyros Island by the Ottoman Empire, Italy, and Greece; overseas migration opportunities; and world transportation changes) and after the war (social changes in peasant societies; worldwide changes in agricultural production practices). The adverse landscape changes documented for Nisyros Island appear to be inevitable for modern Mediterranean rural societies, including those on other islands in this region. The island's unique terraced landscapes may qualify Nisyros to become an archive or repository of old agricultural management techniques to be used by future generations and a living resource for sustainable management.

On the long-lasting sequences of coral reef terraces from SE Sulawesi (Indonesia): Distribution, formation, and global significance

Science.gov (United States)

Pedoja, Kevin; Husson, Laurent; Bezos, Antoine; Pastier, Anne-Morwenn; Imran, Andy Muhammad; Arias-Ruiz, Camilo; Sarr, Anta-Clarisse; Elliot, Mary; Pons-Branchu, Edwige; Nexer, Maëlle; Regard, Vincent; Hafidz, Abdul; Robert, Xavier; Benoit, Laurent; Delcaillau, Bernard; Authemayou, Christine; Dumoulin, Caroline; Choblet, Gaël

2018-05-01

Many islands of the eastern Indonesian Archipelago exhibit Late Cenozoic sequences of coral reef terraces. In SE Sulawesi, on the Tukang Besi and Buton archipelagos, we identified 23 islands bearing such sequences. Remote sensing imagery and field mapping combined to U/Th and 14C dating enable to establish a chronologic framework of the reef terrace sequences from Wangi-Wangi, Buton as well as on the neighbouring, smaller islands of Ular, Siumpu and Kadatua. We identified the terraces from the last interglacial maximum (MIS 5e) at elevations lower than 20 m except on W Kadatua where it is raised at 34 ± 5 m. Such elevations yield low to moderate Upper Pleistocene uplift rates (<0.3 mm yr-1). On SE Buton Island, a sequence culminates at 650 m and includes at least 40 undated strandlines. Next to this exceptional sequence, on the Sampolawa Peninsula, 18 strandlines culminate at 430 m. Dated samples at the base of this sequence (<40 m) yield mean Middle Pleistocene uplift rates of 0.14 ± 0.09 mm yr-1. Extrapolation of these uplift rates compared to the geological setting suggests that the sequences of the Sampolawa Peninsula provide a record of sea-level high-stands for the last 3.8 ± 0.6 Ma. The sequences on SE Buton Island therefore constitute the best preserved long-lasting geomorphic record of Plio-Quaternary sea-level stands worldwide.

The Age of the 20 Meter Solo River Terrace, Java, Indonesia and the Survival of Homo erectus in Asia

Science.gov (United States)

Indriati, Etty; Swisher, Carl C.; Lepre, Christopher; Quinn, Rhonda L.; Suriyanto, Rusyad A.; Hascaryo, Agus T.; Grün, Rainer; Feibel, Craig S.; Pobiner, Briana L.; Aubert, Maxime; Lees, Wendy; Antón, Susan C.

2011-01-01

Homo erectus was the first human lineage to disperse widely throughout the Old World, the only hominin in Asia through much of the Pleistocene, and was likely ancestral to H. sapiens. The demise of this taxon remains obscure because of uncertainties regarding the geological age of its youngest populations. In 1996, some of us co-published electron spin resonance (ESR) and uranium series (U-series) results indicating an age as young as 35–50 ka for the late H. erectus sites of Ngandong and Sambungmacan and the faunal site of Jigar (Indonesia). If correct, these ages favor an African origin for recent humans who would overlap with H. erectus in time and space. Here, we report 40Ar/39Ar incremental heating analyses and new ESR/U-series age estimates from the “20 m terrace" at Ngandong and Jigar. Both data sets are internally consistent and provide no evidence for reworking, yet they are inconsistent with one another. The 40Ar/39Ar analyses give an average age of 546±12 ka (sd±5 se) for both sites, the first reliable radiometric indications of a middle Pleistocene component for the terrace. Given the technical accuracy and consistency of the analyses, the argon ages represent either the actual age or the maximum age for the terrace and are significantly older than previous estimates. Most of the ESR/U-series results are older as well, but the oldest that meets all modeling criteria is 143 ka+20/−17. Most samples indicated leaching of uranium and likely represent either the actual or the minimum age of the terrace. Given known sources of error, the U-series results could be consistent with a middle Pleistocene age. However, the ESR and 40Ar/39Ar ages preclude one another. Regardless, the age of the sites and hominins is at least bracketed between these estimates and is older than currently accepted. PMID:21738710

100 kyr fluvial cut-and-fill terrace cycles since the Middle Pleistocene in the southern Central Andes, NW Argentina

Science.gov (United States)

Tofelde, Stefanie; Schildgen, Taylor F.; Savi, Sara; Pingel, Heiko; Wickert, Andrew D.; Bookhagen, Bodo; Wittmann, Hella; Alonso, Ricardo N.; Cottle, John; Strecker, Manfred R.

2017-09-01

Fluvial fill terraces in intermontane basins are valuable geomorphic archives that can record tectonically and/or climatically driven changes of the Earth-surface process system. However, often the preservation of fill terrace sequences is incomplete and/or they may form far away from their source areas, complicating the identification of causal links between forcing mechanisms and landscape response, especially over multi-millennial timescales. The intermontane Toro Basin in the southern Central Andes exhibits at least five generations of fluvial terraces that have been sculpted into several-hundred-meter-thick Quaternary valley-fill conglomerates. New surface-exposure dating using nine cosmogenic 10Be depth profiles reveals the successive abandonment of these terraces with a 100 kyr cyclicity between 75 ± 7 and 487 ± 34 ka. Depositional ages of the conglomerates, determined by four 26Al/10Be burial samples and U-Pb zircon ages of three intercalated volcanic ash beds, range from 18 ± 141 to 936 ± 170 ka, indicating that there were multiple cut-and-fill episodes. Although the initial onset of aggradation at ∼1 Ma and the overall net incision since ca. 500 ka can be linked to tectonic processes at the narrow basin outlet, the superimposed 100 kyr cycles of aggradation and incision are best explained by eccentricity-driven climate change. Within these cycles, the onset of river incision can be correlated with global cold periods and enhanced humid phases recorded in paleoclimate archives on the adjacent Bolivian Altiplano, whereas deposition occurred mainly during more arid phases on the Altiplano and global interglacial periods. We suggest that enhanced runoff during global cold phases - due to increased regional precipitation rates, reduced evapotranspiration, or both - resulted in an increased sediment-transport capacity in the Toro Basin, which outweighed any possible increases in upstream sediment supply and thus triggered incision. Compared with two

Runoff and sediment generation on bench -terraced hillsides: measurements and up-scaling of a field-based model

NARCIS (Netherlands)

van Dijk, A.I.J.M.; Bruijnzeel, L.A.; Vertessy, R.A.; Ruijter, J.

2006-01-01

Despite widespread bench-terracing, stream sediment yields from agricultural hillsides in upland West Java remain high. We studied the causes of this lack of effect by combining measurements at different spatial scales using an erosion process model. Event runoff and sediment yield from two 4-ha

Landscape change in mediterranean farmlands: impacts of land abandonment on cultivation terraces in portofino (italy) and lesvos (greece)

NARCIS (Netherlands)

Sluis, van der T.; Kizos, T.; Pedroli, G.B.M.

2014-01-01

The Mediterranean landscape has been rapidly changing over the past decades. Many regions saw a population decline, which resulted in changing land use, abandonment of marginal lands and colonisation by shrubs and tree species. Typical features like farming terraces, olive yards, and upland

Luminescence characteristics of quartz and feldspar from tectonically uplifted terraces in Kashmir Basin, Jammu and Kashmir, India

International Nuclear Information System (INIS)

Jaiswal, Manoj K.; Bhat, M.I.; Bali, B.S.; Ahmad, Shabir; Chen, Y.G.

2009-01-01

The Kashmir Valley or the Jhelum basin is an intermontane-basin in NW Himalaya bounded by the Pir Panjal Range in the south and southwest and the Great Himalayan Range in the north and northeast. The valley is marked by active major thrust boundaries in its south and southwestern parts. Remote sensing studies and morphometric analysis suggest neo-tectonic activities and the formation of tectonic terraces due to uplift on the major thrust boundaries in NW Himalayas. The quartz from freshly eroded mountain belts is usually found to show very poor luminescence sensitivity and thus not suitable for optical dating. Similar problems occurred with the quartz from the Srinagar Basin. Due to this, feldspar was selected as a natural dose meter for dating tectonically uplifted terraces in an active and dynamic belt of the NW Himalayas. We report here for the first time the luminescence characteristics of quartz and feldspar minerals from the study area. However, feldspar also shows poor luminescence sensitivity, although enough to perform optical dating. Athermal fading was observed in all the feldspar samples, which was corrected using 'g' values; a large scatter was found in the g values, probably due to intermixing of feldspar grains from varying source rock types and also due to poor luminescence sensitivity. An average g value correction to the mean paleodose was found to agree if compared with the thermo-luminescence date of loess deposit dated earlier. The ages show that the terrace formation started taking place at ∼100 ka in the southwestern part of the Jhelum basin and continued with pulses at 50 ka and 11 ka towards the northwestern part.

Long-term controls on continental-scale bedrock river terrace deposition from integrated clast and heavy mineral assemblage analysis: An example from the lower Orange River, Namibia

Science.gov (United States)

Nakashole, Albertina N.; Hodgson, David M.; Chapman, Robert J.; Morgan, Dan J.; Jacob, Roger J.

2018-02-01

Establishing relationships between the long-term landscape evolution of drainage basins and the fill of sedimentary basins benefits from analysis of bedrock river terrace deposits. These fragmented detrital archives help to constrain changes in river system character and provenance during sediment transfer from continents (source) to oceans (sink). Thick diamondiferous gravel terrace deposits along the lower Orange River, southern Namibia, provide a rare opportunity to investigate controls on the incision history of a continental-scale bedrock river. Clast assemblage and heavy mineral data from seven localities permit detailed characterisation of the lower Orange River gravel terrace deposits. Two distinct fining-upward gravel terrace deposits are recognised, primarily based on mapped stratigraphic relationships (cross-cutting relationships) and strath and terrace top elevations, and secondarily on the proportion of exotic clasts, referred to as Proto Orange River deposits and Meso Orange River deposits. The older early to middle Miocene Proto Orange River gravels are thick (up to 50 m) and characterised by a dominance of Karoo Supergroup shale and sandstone clasts, whereas the younger Plio-Pleistocene Meso Orange River gravels (6-23 m thick) are characterised by more banded iron formation clasts. Mapping of the downstepping terraces indicates that the Proto gravels were deposited by a higher sinuosity river, and are strongly discordant to the modern Orange River course, whereas the Meso deposits were deposited by a lower sinuosity river. The heavy minerals present in both units comprise magnetite, garnet, amphibole, epidote and ilmenite, with rare titanite and zircon grains. The concentration of amphibole-epidote in the heavy minerals fraction increases from the Proto to the Meso deposits. The decrease in incision depths, recorded by deposit thicknesses above strath terraces, and the differences in clast character (size and roundness) and type between the two

Water quality and possible sources of nitrate in the Cimarron Terrace Aquifer, Oklahoma, 2003

Science.gov (United States)

Masoner, Jason R.; Mashburn, Shana L.

2004-01-01

Water from the Cimarron terrace aquifer in northwest Oklahoma commonly has nitrate concentrations that exceed the maximum contaminant level of 10 milligrams per liter of nitrite plus nitrate as nitrogen (referred to as nitrate) set by the U.S. Environmental Protection Agency for public drinking water supplies. Starting in July 2003, the U.S. Geological Survey, in cooperation with the Oklahoma Department of Environmental Quality, conducted a study in the Cimarron terrace aquifer to assess the water quality and possible sources of nitrate. A qualitative and quantitative approach based on multiple lines of evidence from chemical analysis of nitrate, nitrogen isotopes in nitrate, pesticides (indicative of cropland fertilizer application), and wastewater compounds (indicative of animal or human wastewater) were used to indicate possible sources of nitrate in the Cimarron terrace aquifer. Nitrate was detected in 44 of 45 ground-water samples and had the greatest median concentration (8.03 milligrams per liter) of any nutrient analyzed. Nitrate concentrations ranged from chemicals, 3 compounds were hydrocarbons, 2 compounds were industrial chemicals, 2 compounds were pesticides, 1 compound was of animal source, and 1 compound was a detergent compound. The most frequently detected wastewater compound was phenol, which was detected in 23 wells. N,N-diethyl-meta-toluamide (DEET) was detected in water samples from 5 wells. Benzophenone, ethanol- 2-butoxy-phosphate, and tributylphosphate were detected in water samples from 3 wells. Fertilizer was determined to be the possible source of nitrate in samples from 13 of 45 wells sampled, with a15N values ranging from 0.43 to 3.46 permil. The possible source of nitrate for samples from the greatest number of wells (22 wells) was from mixed sources of nitrate from fertilizer, septic or manure, or natural sources. Mixed nitrate sources had a 15N values ranging from 0.25 to 9.83 permil. Septic or manure was determined as the possible

Potentials and pitfalls of depth profile (10Be), burial isochron (26Al/10Be) and palaeomagnetic techniques for dating Early Pleistocene terrace deposits of the Moselle valley (Germany)

Science.gov (United States)

Rixhon, Gilles; Cordier, Stéphane; May, Simon Matthias; Kelterbaum, Daniel; Szemkus, Nina; Keulertz, Rebecca; Dunai, Tibor; Binnie, Steven; Hambach, Ulrich; Scheidt, Stephanie; Brueckner, Helmut

2016-04-01

Throughout the river network of the Rhenish Massif the so-called main terraces complex (MTC) forms the morphological transition between a wide upper palaeovalley and a deeply incised lower valley. The youngest level of this complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature; it is often used as a reference level to identify the beginning of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). Although the main terraces are particularly well preserved in the lower Moselle valley, a questionable age of ca. 800 ka is assumed for the YMT, mainly based on the uncertain extrapolation of controversially interpreted palaeomagnetic data obtained in the Rhine valley. In this study, we applied terrestrial cosmogenic nuclide (TCN) dating (10Be/26Al) and palaeomagnetic dating to Moselle fluvial sediments of the MTC. To unravel the spatio-temporal characteristics of the Pleistocene evolution of the valley, several sites along the lower Moselle were sampled following two distinct TCN dating strategies: depth profiles where the original terrace (palaeo-) surface is well preserved and did not experience a major post-depositional burial (e.g., loess cover); and the isochron technique, where the sediment thickness exceeds 4.5-5 m. One terrace deposit was sampled for both approaches (reference site). In addition, palaeomagnetic sampling was systematically performed in each terrace sampled for TCN measurements. The TCN dating techniques show contrasting results for our reference site. Three main issues are observed for the depth profile method: (i) an inability of the modeled profile to constrain the 10Be concentration of the uppermost sample; (ii) an overestimated density value as model output; and (iii) a probable concentration steady state of the terrace deposits. By contrast, the isochron method yields a burial age estimate of 1.26 +0.29/-0.25 Ma, although one sample showed a depleted 26Al/10Be ratio

Geothermal properties and groundwater flow estimated with a three-dimensional geological model in a late Pleistocene terrace area, central Japan

Science.gov (United States)

Funabiki, A.; Takemura, T.; Hamamoto, S.; Komatsu, T.

2012-12-01

1. Introduction The ground source heat pump (GSHP) is a highly efficient and renewable energy technology for space heating and cooling, with benefits that include energy conservation and reductions in greenhouse gas emissions. One result of the huge Tohoku-oki earthquake and tsunami and the subsequent nuclear disasters is that GSHPs are receiving more attention from the media and they are being introduced by some local governments. Heat generated by underground GSHP installation, however, can pollute the geothermal environment or change groundwater flow patterns . In this study, we estimated possible effects from the use of GSHPs in the Tokyo area with a three-dimensional (3D) geological model. 2. Geological model The Tokyo Metropolitan Area is surrounded by the Late Pleistocene terraces called the Musashino uplands. The terrace surfaces are densely populated residential areas. One of these surfaces, the Shimosueyohi surface, formed along the Tama River during the last deglacial period. The CRE-NUCHS-1 core (Funabiki et al., 2011) was obtained from this surface, and the lithology, heat transfer coefficients, and chemical characteristics of the sediments were analyzed. In this study, we used borehole log data from a 5 km2 area surrounding the CRE-NUCHS-1 core site to create a 3D geological model. In this area, the Pleistocene Kazusa Group is overlain by terrace gravels and a volcanic ash layer called the Kanto Loam. The terrace gravels occur mainly beneath the Kanda, Kitazawa, and Karasuyama rivers , which flow parallel to the Tama River, whereas away from the rivers , the Kanto Loam directly overlies the Kazusa Group sediments. 3. Geothermal disturbance and groundwater flow Using the geological model, we calculated the heat transfer coefficients and groundwater flow velocities in the sediments. Within the thick terrace gravels, which are at relatively shallow depth (8-20 m), heat transfer coefficients were high and groundwater flow was relatively fast. The amount

Planning Method of Eco-environment Restoration Based on Enlarging Terrace and De-farming in Loess Hilly Region——A Case Study of Yangou Catchment

Institute of Scientific and Technical Information of China (English)

Lijuan; DANG; Yong; XU

2013-01-01

After expatiating the guiding ideology,contents,standards and principles of eco-environment restoration based on enlarging terrace and de-farming,this paper discussed the planning method and technical flow of enlarging terrace and garden plot in a small catchment of loess hilly region by means of GIS spatial analysis technology,and then the planning method was applied in Yangou catchment.The result showed that it is practicabl,and the areas of newly-built terrace and garden plot in Yangou catchment are at least 295.06 and 4.61 hm2,so that the areas of basic farmland and garden plot reach 359.23 and 622.69 hm2.After the land use structure is regulated,the forest coverage is 48.87%,and the permanent vegetation coverage is about 75% in Yangou catchment,while sediment reduction benefit is above 80% in slope land.In agricultural development,Yangou catchment can yield 1 645.13 tons of food supplies,above 9 340 tons of apples,and can feed 7 500 sheep every year.

Can terraced pond wetland systems improve urban watershed water quality?

Science.gov (United States)

Li, S.; Ho, M.; Flanagan, N. E.; Richardson, C. J.

2017-12-01

Properly built constructed wetlands are a more economic and efficient way of wastewater treatment compared with traditional methods, although their mechanisms are far from completely understood. As part of the Stream and Wetland Assessment Management Park (SWAMP), which is aimed to improve the water quality of downstream and thereby enhance watershed ecosystem services, a terraced three-pond wetland system was created near Duke University in 2014. This project is expected to promote the retention and settling of pollutants and sediment before runoffs enter downstream flow. The goal of this study is to examine: (1) whether a terraced pond wetland system improves water quality, during both baseline (low flow) and storm events (high flow), which increases pollutant inputs; and (2) how this system functions to remove pollutants, namely what components of this system (plant, soil or water) increase or decrease the level of pollutants. By analyzing a dataset consisting of more than four-year monthly samplings from Pond 1 (first pond in the system) and Pond 3 (last pond in the system), we found that the pond system has reduced total suspended solids (TSS) but only when elevated inputs occur. Dissolved oxygen (DO) is closely related to temperature and macrophytes growth; whereas acidity (pH), total nitrogen (TN), and total phosphorus (TP) did not show retention in the early stages of the system development. This system reaches its optimum for reducing TSS at the second pond, but the third pond has important effects on DO, pH, TN and TP. A monitoring in 2017 shows this pond system significantly reduces TSS while increasing dissolved oxygen and neutralizing pH after a storm event; although greater variations incurred within the system as time progresses after storm, overall retention function remained valid. Retention of the pollutants is primarily accomplished by the settling process, which occurs in stilled waterbody of the ponds and by the filtration of macrophytes. We

Splitting Terraced Houses Into Single Units Using Oblique Aerial Imagery

Science.gov (United States)

Dahlke, D.

2017-05-01

This paper introduces a method to subdivide complex building structures like terraced houses into single house units comparable to units available in a cadastral map. 3D line segments are detected with sub-pixel accuracy in traditional vertical true orthomosaics as well as in innovative oblique true orthomosaics and their respective surface models. Hereby high gradient strengths on roofs as well as façades are taken into account. By investigating the coplanarity and frequencies within a set of 3D line segments, individual cut lines for a building complex are found. The resulting regions ideally describe single houses and thus the object complexity is reduced for subsequent topological, semantical or geometrical considerations. For the chosen study area with 70 buidling outlines a hit rate of 80% for cut lines is achieved.

Palaeoenvironmental implication of grain-size compositions of terrace deposits on the western Chinese Loess Plateau

Science.gov (United States)

Liu, Xingxing; Sun, Youbin; Vandenberghe, Jef; Li, Ying; An, Zhisheng

2018-06-01

Sedimentary sequences that developed on river terraces have been widely investigated to reconstruct high-resolution palaeoclimatic changes since the last deglaciation. However, frequent changes in sedimentary facies make palaeoenvironmental interpretation of grain-size variations relatively complicated. In this paper, we employed multiple grain-size parameters to discriminate the sedimentary characteristics of aeolian and fluvial facies in the Dadiwan (DDW) section on the western Chinese Loess Plateau. We found that wind and fluvial dynamics have quite different impacts on the grain-size compositions, with distinctive imprints on the distribution pattern. By using a lognormal distribution fitting approach, two major grain-size components sensitive to aeolian and fluvial processes, respectively, were distinguished from the grain-size compositions of the DDW terrace deposits. The fine grain-size component (GSC2) represents mixing of long-distance aeolian and short-distance fluvial inputs, whilst the coarse grain-size component (GSC3) is mainly transported by wind from short-distance sources. Thus GSC3 can be used to infer the wind intensity. Grain-size variations reveal that the wind intensity experienced a stepwise shift from large-amplitude variations during the last deglaciation to small-amplitude oscillations in the Holocene, corresponding well to climate changes from regional to global context.

Users’ Perceptions on Pedestrian Prioritized Neighborhoods: a study on Terrace Row Housing Estates in Malaysia

OpenAIRE

Tareef Hayat Khan; Abubakar Danladi Isah; Elahe Anjomshoaa; Soheil Sabri

2015-01-01

Malaysia is currently enjoying an overhang of housing supply. The focus is gradually shifting from providing just a mere shelter to something more socially. Terrace row housing estates in Malaysia is the major prototype of housing in the country. Pedestrian activities are catalyst to social interaction, but have been ignored in this model. During the last century, motor age established the supremacy of car prioritized models over that of pedestrians around the world, Malaysia has ...

Environmental impact of introducing plant covers in the taluses of orchard terraces: implications for erosion and agricultural runoff control

NARCIS (Netherlands)

Rodriguez Pleguezuelo, C.R.; Duran Zuazo, V.H.; Francia Martinez, J.R.; Martin Peinado, F.J.; Graaff, de J.; Muriel Fernandez, J.L.

2011-01-01

South-eastern Spain, and in particular the coastal areas of Granada and Malaga, feature a large area under subtropical crops, with orchards established on terraces built along the slopes of the mountainous areas. The climate, characterized by periodically heavy rainfall, variable in space and time,

Correlations of cave levels, stream terraces and planation surfaces along the River Mur-Timing of landscape evolution along the eastern margin of the Alps.

Science.gov (United States)

Wagner, Thomas; Fritz, Harald; Stüwe, Kurt; Nestroy, Othmar; Rodnight, Helena; Hellstrom, John; Benischke, Ralf

2011-11-01

The transition zone of the Eastern Alps to the Pannonian Basin provides one of the best sources of information on landscape evolution of the Eastern Alpine mountain range. The region was non-glaciated during the entire Pleistocene. Thus, direct influence of glacial carving as a landscape forming process can be excluded and relics of landforms are preserved that date back to at least the Late Neogene. In this study, we provide a correlation between various planation surfaces across the orogen-basin transition. In particular, we use stream terraces, planation surfaces and cave levels that cover a vertical spread of some 700 m. Our correlation is used to show that both sides of the transition zone uplifted together starting at least about 5 Ma ago. For our correlation we use recently published terrestrial cosmogenic nuclide (TCN) burial ages from cave sediments, new optically stimulated luminescence (OSL) ages of a stream terrace and U-Th ages from speleothems. Minimum age constraints of cave levels from burial ages of cave sediments covering the last ~ 4 Ma are used to place age constraints on surface features by parallelizing cave levels with planation surfaces. The OSL results for the top section of the type locality of the Helfbrunn terrace suggest an Early Würm development (80.5 ± 3.7 to 68.7 ± 4.0 ka). The terrace origin as a penultimate gravel deposit (in classical Alpine terminology Riss) is therefore questioned. U-series speleothem ages from caves nearby indicate formation during Marine Isotope Stages (MIS) 5c and 5a which are both interstadial warm periods. As OSL ages from the terrace also show a time of deposition during MIS 5a ending at the MIS 5/4 transition, this supports the idea of temperate climatic conditions at the time of deposition. In general, tectonic activity is interpreted to be the main driving force for the formation and evolution of these landforms, whilst climate change is suggested to be of minor importance. Obvious hiatuses

Disentangling Values in the Interrelations between Cultural Ecosystem Services and Landscape Conservation—A Case Study of the Ifugao Rice Terraces in the Philippines

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Bianca Tilliger

2015-09-01

Full Text Available In the past few years, there has been a growing amount of research on economic quantifications and valuations of ecosystem services (ES in agricultural systems. However, little attention has been given to cultural ESs (CES in general and their link to the landscape in particular. This paper tries to tackle this gap with a case study on the Ifugao Rice Terraces of the Philippines. The study aims to understand the interrelations between the different CESs and their relationships with the landscape. Besides contributing to knowledge about the degradation of the rice terraces, this study was conducted in order to discuss at a theoretical level how CESs and their relationship with the landscape must be addressed in ES management and policy decisions. The methodological approach includes a combination of semi-structured interviews (n = 60 and a perception survey (n = 66. The results reveal that CESs, apart from being interrelated, are also responsible for and affected by the degradation of the rice terraces, which is why they are important factors to consider in ecosystem conservation. This paper finally provides policy recommendations for the empirical case and demonstrates the importance of connecting CES analysis with landscape studies looking at agricultural systems.

Eco-environment Restoration and Regional Differentiation Characteristics Based on “Building Terrace and Returning Slope Farmland to Forests and Grass”

Institute of Scientific and Technical Information of China (English)

Yanhua; LIU; Yong; XU

2013-01-01

Based on the scientific and technological achievements in the past decade in the Loess Hilly-gully Region and the successful demonstration experience in Yan’an Yangou watershed, we summarize the characteristics of eco-environment restoration pattern based on "building terrace and returning slope farmland to forests and grass". According to the data on land use, slope farmland and the agricultural population in 1999, we calculate the area of new terrace that needs to be built, the area of garden plot that needs to be extended, vegetation restoration area and investment demand in counties (cities, districts). Establishing and using some indicators, such as basic farmland extension indicator, garden plot extension indicator, vegetation restoration index and investment demand density, we conduct type classification and analysis of regional differentiation characteristics in 55 counties (cities, districts). The results show that in the Loess Hilly-gully Region, 691 600 hm2 of new terrace needs to be built, 792 000 hm2 of economic forests and orchards need to be extended, 5 410 200 hm2 of vegetation needs to be restored, and the total investment demand is 15.82 billion yuan; in terms of geographical distribution, obviously there are two key areas for eco-environment restoration (one is located in the border area between northern Shaanxi and northwestern Shanxi, and the other is located in the eastern Gansu and southern Ningxia area); the classified regional guidance policies should be formulated as soon as possible, and the limited funds should be concentrated in the key areas.

Comparison between Urea and Goat Manure as Sources of Nitrogen for Napier Grass Grown on Terraced Hill

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Rahman, M.M.

2016-12-01

Full Text Available Effects of two nitrogen (N sources on dry matter (DM yield and nutritive value of Napier grass were evaluated. The nitrogen (N fertiliser (at rate of 300 kg N ha?1 year?1 was applied by dividing the terraces of a hill under two treatments: T1 (urea and T2 (goat manure. There were three replicates of each treatment arranged within three blocks in a completely randomised design. Grass was cut at about 60?day interval. In the first to fourth harvests, grass receiving manure had higher plant height than those with urea application. Grass receiving manure had higher DM yield than urea in almost all of the cuttings. In the fourth harvest, grass receiving urea contained higher DM and organic matter (OM than manure. Similar result was found for fifth harvest where urea gave higher crude protein (CP than manure. Irrespective of harvesting frequencies, average DM, OM, CP and neutral detergent fibre contents were not significantly different between grasses fertilised with manure and urea. In conclusion, manure is recommended for economical cultivation of Napier grass on terrace of hill.

Geohydrologic units and water-level conditions in the Terrace alluvial aquifer and Paluxy Aquifer, May 1993 and February 1994, near Air Force Plant 4, Fort Worth area, Texas

Science.gov (United States)

Rivers, Glen A.; Baker, Ernest T.; Coplin, L.S.

1996-01-01

The terrace alluvial aquifer underlying Air Force Plant 4 and the adjacent Naval Air Station (formerly Carswell Air Force Base) in the Fort Worth area, Texas, is contaminated locally with organic and metal compounds. Residents south and west of Air Force Plant 4 and the Naval Air Station are concerned that contaminants might enter the underlying Paluxy aquifer, which provides water to the city of White Settlement, south of Air Force Plant 4, and to residents west of Air Force Plant 4. The U.S. Environmental Protection Agency has qualified Air Force Plant 4 for Superfund cleanup. The pertinent geologic units include -A~rom oldest to youngest the Glen Rose, Paluxy, and Walnut Formations, Goodland Limestone, and terrace alluvial deposits. Except for the Glen Rose Formation, all units crop out at or near Air Force Plant 4 and the Naval Air Station. The terrace alluvial deposits, which nearly everywhere form the land surface, range from 0 to about 60 feet thick. These deposits comprise a mostly unconsolidated mixture of gravel, sand, silt, and clay. Mudstone and sandstone of the Paluxy Formation crop out north, west, and southwest of Lake Worth and total between about 130 and about 175 feet thick. The terrace alluvial deposits and the Paluxy Formation comprise the terrace alluvial aquifer and the Paluxy aquifer, respectively. These aquifers are separated by the Goodland-Walnut confining unit, composed of the Goodland Limestone and (or) Walnut Formation. Below the Paluxy aquifer, the Glen Rose Formation forms the Glen Rose confining unit. Water-level measurements during May 1993 and February 1994 from wells in the terrace alluvial aquifer indicate that, regionally, ground water flows toward the east-southeast beneath Air Force Plant 4 and the Naval Air Station. Locally, water appears to flow outward from ground-water mounds maintained by the localized infiltration of precipitation and reportedly by leaking water pipes and sanitary and (or) storm sewer lines beneath the

10Be dating of the Main Terrace level in the Amblève valley (Ardennes, Belgium): new age constraint on the archaeological and palaeontological filling of the Belle-Roche palaeokarst

Science.gov (United States)

Rixhon, Gilles; Bourlès, Didier L.; Braucher, Régis; Siame, Lionel; Cordy, Jean-Marie; Demoulin, Alain

2014-05-01

It is still disputed whether very old archaeological and palaeontological remains found in the Belle-Roche palaeocave (eastern Belgium) pertain to the Early (˜1 Ma) or Middle (˜0.5 Ma) Pleistocene. Here, in situ-produced cosmogenic 10Be concentrations from a depth profile in nearby sediments of the Belle-Roche terrace (Amblève Main Terrace level) are used as an indirect solution of this chronological issue. The distribution of 10Be concentrations in the upper 3 m of this profile displays the theoretically expected exponential decrease with depth. Assuming a single exposure episode, we obtain a best fit age of 222.5±31 ka for the time of terrace abandonment. However, below 3 m, the 10Be concentrations show a marked progressive increase with depth. This distinctive cosmogenic signal is interpreted as the result of slow aggradation of the fluvial deposits over a lengthy interval. Modelling of the whole profile thus suggests that the onset of the terrace formation occurred at around 550 ka, with a sediment accumulation rate of ˜20 mm/ka. Based on two slightly different reconstructions of the geomorphic evolution of the area and a discussion of the temporal link between the cave and Main Terrace levels, we conclude that the fossil-bearing layers in the palaeokarst pertain most probably to MIS 14-13 (or possibly MIS 12-11) and the artifact-bearing layer to MIS 13 (or possibly MIS 11). This age estimate for the large mammal association identified in the Belle-Roche palaeokarst and the attribution to MIS 14-13 of a similar fauna found in the lowermost fossiliferous layers of the Caune de l'Arago (Tautavel) are in mutual support. Our results therefore confirm the status of the Belle-Roche site as a reference site for the Cromerian mammal association and the Early Palaeolithic industry in NW Europe.

Correlating sea level rise still-stands to marine terraces and undiscovered submerged shoreline features in the Channel Islands (USA) using autonomous and remotely operated systems

Science.gov (United States)

Raineault, N.; Ballard, R. D.; Fahy, J.; Mayer, L. A.; Heffron, E.; Krasnosky, K.; Roman, C.; Schmidt, V. E.; McLeod, A.; Bursek, J.; Broad, K.

2017-12-01

In 2017, the Ocean Exploration Trust aggregated onboard and autonomous mapping technologies to identify and explore paleo shorelines and discover previously undocumented submerged shoreline features in and around the Channel Islands offshore of California. Broad area mapping was conducted with the hull mounted multibeam echosounder aboard the E/V Nautilus. This Kongsberg EM302 provided maps at 2-10 m resolution, at depths generally greater than 50 m. From this data marine terraces were identified for higher resolution mapping via an Autonomous Surface Vehicle (ASV). The precision data from the ASV's Kongsberg EM2040p echosounder allowed identification of the knickpoints associated with cliffs on the landward extent of each terrace. Sub-sea cave targets were identified using backscatter and slope maps from a combination of both the broad area and high resolution multibeam data. To ground-truth the targets identified through mapping, remotely operated vehicles (ROVs) and a highly specialized team of cave divers explored these targets. The results from the visual inspection were then fed back into the analysis fostering the rapid iteration of the onboard identification criteria and resulted in locating submerged shorelines containing numerous large caves, arches, and concretions. Caves were found at still-stands at 8, 33, 66, and 103 m depth at Santa Cruz Island, Santa Barbara Island platform, and Osborn Bank, along the vertical escarpment at the cliff-face and aligned with the strike of fractures in the volcanic rock. These terraces correspond to different sea level still-stands. ROV grab samples of fossiliferous marine terraces will provide ages and aid in reconstructions of sea level change and tectonic history for each location. Finally, caves were mapped in sub-cm resolution using a Kongsberg M3 sonar mounted vertically on the front of the ROV to test the capabilities of the system to provide accurate information about exterior dimensions and morphology.

Quantitative Study of Green Area for Climate Sensitive Terraced Housing Area Design in Malaysia

International Nuclear Information System (INIS)

Yeo, O T S; Saito, K; Said, I

2014-01-01

Neighbourhood plays a significant role in peoples' daily lives. Nowadays, terraced housing is common in Malaysia, and green areas in the neighborhood are not used to their maximum. The aim of the research is to quantify the types of green area that are most efficient for cooling the environment for thermal comfort and mitigation of Urban Heat Island. Spatial and environmental inputs are manipulated for the simulation using Geographic Information System (GIS) integrated with computational microclimate simulation. The outcome of this research is a climate sensitive housing environment model framework on the green area to solve the problem of Urban Heat Island

Q fever outbreak in the terraced vineyards of Lavaux, Switzerland

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C. Bellini

2014-07-01

Full Text Available Coxiella burnetii infection (Q fever is a widespread zoonosis with low endemicity in Switzerland, therefore no mandatory public report was required. A cluster of initially ten human cases of acute Q fever infections characterized by prolonged fever, asthenia and mild hepatitis occurred in 2012 in the terraced vineyard of Lavaux. Epidemiological investigations based on patients’ interviews and veterinary investigations included environmental sampling as well as Coxiella-specific serological assay and molecular examinations (real-time PCR in vaginal secretions of suspected sheep. These investigations demonstrated that 43% of sheep carried the bacteria whereas 30% exhibited anti-Coxiella antibodies. Mitigation measures, including limiting human contacts with the flock, hygiene measures, flock vaccination and a public official alert, have permitted the detection of four additional human cases and the avoidance of a much larger outbreak. Since November 2012, mandatory reporting of Q fever to Swiss public health authorities has been reintroduced. A close follow up of human cases will be necessary to identify chronic Q fever.

Tailor-made ultrathin manganese oxide nanostripes: ‘magic widths’ on Pd(1 1 N) terraces

Science.gov (United States)

Franchini, C.; Li, F.; Surnev, S.; Podloucky, R.; Allegretti, F.; Netzer, F. P.

2012-02-01

The growth of ultrathin two-dimensional manganese oxide nanostripes on vicinal Pd(1 1 N) surfaces leads to particular stable configurations for certain combinations of oxide stripe and substrate terrace widths. Scanning tunneling microscopy and high-resolution low-energy electron diffraction measurements reveal highly ordered nanostructured surfaces with excellent local and long-range order. Density functional theory calculations provide the physical origin of the stabilization mechanism of ‘magic width’ stripes in terms of a finite-size effect, caused by the significant relaxations observed at the stripe boundaries.

Using Curved Crystals to Study Terrace-Width Distributions.

Science.gov (United States)

Einstein, Theodore L.

Recent experiments on curved crystals of noble and late transition metals (Ortega and Juurlink groups) have renewed interest in terrace width distributions (TWD) for vicinal surfaces. Thus, it is timely to discuss refinements of TWD analysis that are absent from the standard reviews. Rather than by Gaussians, TWDs are better described by the generalized Wigner surmise, with a power-law rise and a Gaussian decay, thereby including effects evident for weak step repulsion: skewness and peak shifts down from the mean spacing. Curved crystals allow analysis of several mean spacings with the same substrate, so that one can check the scaling with the mean width. This is important since such scaling confirms well-established theory. Failure to scale also can provide significant insights. Complicating factors can include step touching (local double-height steps), oscillatory step interactions mediated by metallic (but not topological) surface states, short-range corrections to the inverse-square step repulsion, and accounting for the offset between adjacent layers of almost all surfaces. We discuss how to deal with these issues. For in-plane misoriented steps there are formulas to describe the stiffness but not yet the strength of the elastic interstep repulsion. Supported in part by NSF-CHE 13-05892.

Records of human occupation from Pleistocene river terrace and aeolian sediments in the Arneiro depression (Lower Tejo River, central eastern Portugal)

DEFF Research Database (Denmark)

Cunha, Pedro P.; Almeida, Nelson A.C.; Aubry, Thierry

2012-01-01

In the uppermost reach of the Lower Tejo River (eastern central Portugal), where the river crosses two quartzite ridges that separate the Ródão (upstream) and Arneiro (downstream) depressions, Palaeolithic artefacts have been recovered from three lower river terrace levels and a cover unit of aeo...

Comparison of reactivity on step and terrace sites of Pd (3 3 2) surface for the dissociative adsorption of hydrogen: A quantum chemical molecular dynamics study

International Nuclear Information System (INIS)

Ahmed, Farouq; Nagumo, Ryo; Miura, Ryuji; Ai, Suzuki; Tsuboi, Hideyuki; Hatakeyama, Nozomu; Endou, Akira; Takaba, Hiromitsu; Kubo, Momoji; Miyamoto, Akira

2011-01-01

The notion of 'active sites' is fundamental to heterogeneous catalysis. However, the exact nature of the active sites, and hence the mechanism by which they act, are still largely a matter of speculation. In this study, we have presented a systematic quantum chemical molecular dynamics (QCMD) calculations for the interaction of hydrogen on different step and terrace sites of the Pd (3 3 2) surface. Finally the dissociative adsorption of hydrogen on step and terrace as well as the influence of surface hydrogen vacancy for the dissociative adsorption of hydrogen has been investigated through QCMD. This is a state-of-the-art method for calculating the interaction of atoms and molecules with metal surfaces. It is found that fully hydrogen covered (saturated) step sites can dissociate hydrogen moderately and that a monovacancy surface is suitable for significant dissociative adsorption of hydrogen. However in terrace site of the surface we have found that dissociation of hydrogen takes place only on Pd sites where the metal atom is not bound to any pre-adsorbed hydrogen atoms. Furthermore, from the molecular dynamics and electronic structure calculations, we identify a number of consequences for the interpretation and modeling of diffusion experiments demonstrating the coverage and directional dependence of atomic hydrogen diffusion on stepped palladium surface.

Occupants’ Utilization of Natural Ventilation: A Study of Selected Terrace House Designs in Hot-humid Climate

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Ibiyeye AI

2015-05-01

Full Text Available With increased time spent indoors and demand for enhanced comfort levels, energy consumption in homes is rising mostly for cooling, particularly in hot-humid regions. Natural ventilation is seen as an alternative to mechanical cooling as it is totally independent on energy and has been reported to be of high potential. However, little information is available on the utilization of natural ventilation in individual living spaces in different house designs. Therefore, this paper aims to investigate occupants’ utilization of natural ventilation in living spaces under different terrace house designs in hot-humid climate and also the relationship between the openings and occupants’ satisfaction with natural ventilation. Five (5 different terrace house types in Putrajaya, Malaysia with different opening design characteristics were selected for the study. A total of 298 households from these house types were surveyed and results show that occupants mostly open their windows during the daytime to capture breeze from outside despite the fact that they owned air-conditioners. In terms of occupants’ level of satisfaction with indoor ventilation when utilizing natural ventilation, majority rated neither satisfied nor unsatisfied. Further regression analysis reveals that this level of satisfaction is significantly related to opening sizes that are in accordance with the law, duration of opening windows and AC ownership. Findings from this study will shed more light on behavioural pattern of occupants of residential buildings towards natural ventilation provisions and highlight the importance of conforming to the law governing them.

Ti and N adatom descent pathways to the terrace from atop two-dimensional TiN/TiN(001) islands

Energy Technology Data Exchange (ETDEWEB)

Edström, D., E-mail: daned@ifm.liu.se [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Sangiovanni, D.G.; Hultman, L.; Chirita, V. [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Petrov, I.; Greene, J.E. [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping (Sweden); Frederick Seitz Materials Research Laboratory and the Materials Science Department, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

2014-05-02

We use classical molecular dynamics and the modified embedded atom method to determine residence times and descent pathways of Ti and N adatoms on square, single-atom-high, TiN islands on TiN(001). Simulations are carried out at 1000 K, which is within the optimal range for TiN(001) epitaxial growth. Results show that the frequency of descent events, and overall adatom residence times, depend strongly on both the TiN(001) diffusion barrier for each species as well as the adatom island-edge location immediately prior to descent. Ti adatoms, with a low diffusion barrier, rapidly move toward the island periphery, via funneling, where they diffuse along upper island edges. The primary descent mechanism for Ti adatoms is via push-out/exchange with Ti island-edge atoms, a process in which the adatom replaces an island edge atom by moving down while pushing the edge atom out onto the terrace to occupy an epitaxial position along the island edge. Double push-out events are also observed for Ti adatoms descending at N corner positions. N adatoms, with a considerably higher diffusion barrier on TiN(001), require much longer times to reach island edges and, consequently, have significantly longer residence times. N adatoms are found to descend onto the terrace by direct hopping over island edges and corner atoms, as well as by concerted push-out/exchange with N atoms adjacent to Ti corners. For both adspecies, we also observe several complex adatom/island interactions, before and after descent onto the terrace, including two instances of Ti island-atom ascent onto the island surface. - Highlights: • We use classical molecular dynamics to model Ti and N adatom migration on TiN(001) islands. • N adatoms remain on islands significantly longer than Ti adatoms. • Ti adatoms descend via push-out/exchange, N adatoms primarily by direct hops. • N adatoms act as precursors for multilayer formation and surface roughening.

Ti and N adatom descent pathways to the terrace from atop two-dimensional TiN/TiN(001) islands

International Nuclear Information System (INIS)

Edström, D.; Sangiovanni, D.G.; Hultman, L.; Chirita, V.; Petrov, I.; Greene, J.E.

2014-01-01

We use classical molecular dynamics and the modified embedded atom method to determine residence times and descent pathways of Ti and N adatoms on square, single-atom-high, TiN islands on TiN(001). Simulations are carried out at 1000 K, which is within the optimal range for TiN(001) epitaxial growth. Results show that the frequency of descent events, and overall adatom residence times, depend strongly on both the TiN(001) diffusion barrier for each species as well as the adatom island-edge location immediately prior to descent. Ti adatoms, with a low diffusion barrier, rapidly move toward the island periphery, via funneling, where they diffuse along upper island edges. The primary descent mechanism for Ti adatoms is via push-out/exchange with Ti island-edge atoms, a process in which the adatom replaces an island edge atom by moving down while pushing the edge atom out onto the terrace to occupy an epitaxial position along the island edge. Double push-out events are also observed for Ti adatoms descending at N corner positions. N adatoms, with a considerably higher diffusion barrier on TiN(001), require much longer times to reach island edges and, consequently, have significantly longer residence times. N adatoms are found to descend onto the terrace by direct hopping over island edges and corner atoms, as well as by concerted push-out/exchange with N atoms adjacent to Ti corners. For both adspecies, we also observe several complex adatom/island interactions, before and after descent onto the terrace, including two instances of Ti island-atom ascent onto the island surface. - Highlights: • We use classical molecular dynamics to model Ti and N adatom migration on TiN(001) islands. • N adatoms remain on islands significantly longer than Ti adatoms. • Ti adatoms descend via push-out/exchange, N adatoms primarily by direct hops. • N adatoms act as precursors for multilayer formation and surface roughening

Evaluation of Integration Degree of the ASG-EUPOS Polish Reference Networks With Ukrainian GeoTerrace Network Stations in the Border Area

Science.gov (United States)

Siejka, Zbigniew

2017-09-01

GNSS systems are currently the basic tools for determination of the highest precision station coordinates (e.g. basic control network stations or stations used in the networks for geodynamic studies) as well as for land, maritime and air navigation. All of these tasks are carried out using active, large scale, satellite geodetic networks which are complex, intelligent teleinformatic systems offering post processing services along with corrections delivered in real-time for kinematic measurements. Many countries in the world, also in Europe, have built their own multifunctional networks and enhance them with their own GNSS augmentation systems. Nowadays however, in the era of international integration, there is a necessity to consider collective actions in order to build a unified system, covering e.g. the whole Europe or at least some of its regions. Such actions have already been undertaken in many regions of the world. In Europe such an example is the development for EUPOS which consists of active national networks built in central eastern European countries. So far experience and research show, that the critical areas for connecting these networks are border areas, in which the positioning accuracy decreases (Krzeszowski and Bosy, 2011). This study attempts to evaluate the border area compatibility of Polish ASG-EUPOS (European Position Determination System) reference stations and Ukrainian GeoTerrace system reference stations in the context of their future incorporation into the EUPOS. The two networks analyzed in work feature similar hardware parameters. In the ASG-EUPOS reference stations network, during the analyzed period, 2 stations (WLDW and CHEL) used only one system (GPS), while, in the GeoTerrace network, all the stations were equipped with both GPS and GLONASS receivers. The ASG EUPOS reference station network (95.6%) has its average completeness greater by about 6% when compared to the GeoTerrace network (89.8%).

A coupled distributed hydrological-stability analysis on a terraced slope of Valtellina (northern Italy)

Science.gov (United States)

Camera, C.; Apuani, T.; Masetti, M.

2013-02-01

The aim of this work was to understand and reproduce the hydrological dynamics of a slope, which was terraced using dry-stone retaining walls and its response to these processes in terms of stability at the slope scale. The slope studied is located in Valtellina (northern Italy), near the village of Tresenda, and in the last 30 yr has experienced several soil slip/debris flow events. In 1983 alone, such events caused the death of 18 people. Direct observation of the events of 1983 enabled the principal triggering cause of these events to be recognized in the formation of an overpressure at the base of a dry-stone wall, which caused its failure. To perform the analyses it is necessary to include the presence of dry-stone walls, considering the importance they have in influencing hydrological and geotechnical processes at the slope scale. This requires a very high resolution DEM (1 m × 1 m because the walls are from 0.60 m to 1.0 m wide) that has been appositely derived. A hydrogeological raster-based model, which takes into account both the unsaturated and saturated flux components, was applied. This was able to identify preferential infiltration zones and was rather precise in the prediction of maximum groundwater levels, providing valid input for the distributed stability analysis. Results of the hydrogeological model were used for the successive stability analysis. Sections of terrace were identified from the downslope base of a retaining wall to the top of the next downslope retaining wall. Within each section a global method of equilibrium was applied to determine its safety factor. The stability model showed a general tendency to overestimate the amount of unstable areas. An investigation of the causes of this unexpected behavior was, therefore, also performed in order to progressively improve the reliability of the model.

Agricultural terraces montoring and modeling: a field survey in Chianti region, Firenze, Italy - First part

Science.gov (United States)

Preti, Federico; Caruso, Marco; Dani, Andrea; Errico, Alessandro; Guastini, Enrico; Trucchi, Paolo

2015-04-01

The two abstracts present the design and set-up of an experimental field plant whose aim is the study and modeling of water circulation in a terraced slope together with its influence on the stability of the retaining dry stone walls. The pilot plant is located at "Fattoria di Lamole" (Greve in Chianti, Firenze, Italy) where both ancient and recently restored or rebuilt dry stone retaining walls are present. The intense vineyards cultivation makes it very representative in terms of range of external stresses that affect both hillslopes and walls. The research is developed within a bigger framework of landscape preservation as a way to prevent hydrogeological instabilities and landslide risks. First Part A first/preliminary field survey was carried out in order to estimate the hydraulic and mechanical soil characteristics. Field saturated hydraulic conductivity measurements with the Simplified Falling Head (SFH) method on a terrace along an alignment were performed. Infiltrometer tests with a double ring device and soil texture determinations with both fine particle-size and skeleton fraction distributions were also performed. The Direct shear test on undisturbed and reconstituted soil samples will offer an estimation of the Mohr-Coulomb failure envelope parameters (friction angle and cohesion). A reference portion of a dry stone wall will be also monitored. Lateral earth pressure at backfill-retaining wall interface (compared to temperature and air pressure measured values), backfill volumetric water content (both in saturated and unsaturated states) and ground-water level are measured. Acknowledgements Italian Research Project of Relevant Interest (PRIN2010-2011), prot. 20104ALME4, National network for monitoring, modeling, and sustainable management of erosion processes in agricultural land and hilly-mountainous area

Chemical weathering of a marine terrace chronosequence, Santa Cruz, California I: Interpreting rates and controls based on soil concentration-depth profiles

Science.gov (United States)

White, A.F.; Schulz, M.S.; Vivit, D.V.; Blum, A.E.; Stonestrom, David A.; Anderson, S.P.

2008-01-01

The spatial and temporal changes in element and mineral concentrations in regolith profiles in a chronosequence developed on marine terraces along coastal California are interpreted in terms of chemical weathering rates and processes. In regoliths up to 15 m deep and 226 kyrs old, quartz-normalized mass transfer coefficients indicate non-stoichiometric preferential release of Sr > Ca > Na from plagioclase along with lesser amounts of K, Rb and Ba derived from K-feldspar. Smectite weathering results in the loss of Mg and concurrent incorporation of Al and Fe into secondary kaolinite and Fe-oxides in shallow argillic horizons. Elemental losses from weathering of the Santa Cruz terraces fall within the range of those for other marine terraces along the Pacific Coast of North America. Residual amounts of plagioclase and K-feldspar decrease with terrace depth and increasing age. The gradient of the weathering profile bs is defined by the ratio of the weathering rate, R to the velocity at which the profile penetrates into the protolith. A spreadsheet calculator further refines profile geometries, demonstrating that the non-linear regions at low residual feldspar concentrations at shallow depth are dominated by exponential changes in mineral surface-to-volume ratios and at high residual feldspar concentrations, at greater depth, by the approach to thermodynamic saturation. These parameters are of secondary importance to the fluid flux qh, which in thermodynamically saturated pore water, controls the weathering velocity and mineral losses from the profiles. Long-term fluid fluxes required to reproduce the feldspar weathering profiles are in agreement with contemporary values based on solute Cl balances (qh = 0.025-0.17 m yr-1). During saturation-controlled and solute-limited weathering, the greater loss of plagioclase relative to K-feldspar is dependent on the large difference in their respective solubilities instead of the small difference between their respective

Fish scale terrace GaInN/GaN light-emitting diodes with enhanced light extraction

Science.gov (United States)

Stark, Christoph J. M.; Detchprohm, Theeradetch; Zhao, Liang; Paskova, Tanya; Preble, Edward A.; Wetzel, Christian

2012-12-01

Non-planar GaInN/GaN light-emitting diodes were epitaxially grown to exhibit steps for enhanced light emission. By means of a large off-cut of the epitaxial growth plane from the c-plane (0.06° to 2.24°), surface morphologies of steps and inclined terraces that resemble fish scale patterns could controllably be achieved. These patterns penetrate the active region without deteriorating the electrical device performance. We find conditions leading to a large increase in light-output power over the virtually on-axis device and over planar sapphire references. The process is found suitable to enhance light extraction even without post-growth processing.

A multiple dating approach (luminescence and electron spin resonance) to assess rates of crustal deformation using Quaternary fluvial terraces of the lower Moulouya River (NE Morocco)

Science.gov (United States)

Bartz, Melanie; Rixhon, Gilles; Duval, Mathieu; King, Georgina; Brückner, Helmut

2017-04-01

The Moulouya River, the largest catchment in Morocco, drains an area characterized by active crustal deformation during the Late Cenozoic due to the convergence between the African and Eurasian plates. Our study focuses on the lowermost reach of the river in NE Morocco, where a thrust zone associated with N-S compressive shortening in this region was identified (Barcos et al., 2014; Rixhon et al., 2017). New geomorphological results demonstrate contrasting fluvial environments on each side of the thrust: long-lasting fluvial aggradation, materialized by >37 m-thick stacked fill terraces, and the development of a well-preserved terrace staircase, with three Pleistocene terrace levels, occurred in the footwall and the hanging wall, respectively (Rixhon et al., 2017). Here, we present a preliminary geochronological background for these contrasting terrace systems based on a multiple dating approach. Samples for (i) luminescence (pIRIR225 and pIRIR290 dating of coarse-grained K-feldspars) and (ii) electron spin resonance (ESR dating of coarse-grained quartz) from four different profiles were collected. (i) Due to the application of the athermal detrapping model by Huntley (2006) (modified after Kars et al., 2008), it appears that the feldspar signals are in sample specific field saturation. Our results yielded minimum ages of 0.9 Ma and 0.7 Ma for the footwall and hanging wall, respectively. (ii) Using the multiple centre approach with ESR dating (Duval et al., 2015), we measured both the aluminium (Al) and the titanium (Ti) centres in order to evaluate whether they would provide consistent results. Results indicate that De values of the Al centre are either slightly higher compared to those of the Ti centre or they agree within a 1σ-error range, which may simply be due to the slower bleaching kinetics of the Al centre. Thus, the ESR ages were inferred from the Ti centre. Ages between 1.35±0.10 and 1.17±0.10 Ma in the footwall show sediment aggradation between MIS

LiDAR derived high resolution topography: the next challenge for the analysis of terraces stability and vineyard soil erosion

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Federico Preti

2013-09-01

Full Text Available The soil erosion in the vineyards is a critical issue that could affect their productivity, but also, when the cultivation is organized in terraces, increase the risk due to derived slope failure processes. If terraces are not correctly designed or maintained, a progressively increasing of gully erosion affects the structure of the walls. The results of this process is the increasing of connectivity and runoff. In order to overcome such issues it is really important to recognize in detail all the surface drainage paths, thus providing a basis upon which develop a suitable drainage system or provide structural measures for the soil erosion risk mitigation. In the last few years, the airborne LiDAR technology led to a dramatic increase in terrain information. Airborne LiDAR and Terrestrial Laser Scanner derived high-resolution Digital Terrain Models (DTMs have opened avenues for hydrologic and geomorphologic studies (Tarolli et al., 2009. In general, all the main surface process signatures are correctly recognized using a DTM with cell sizes of 1 m. However sub-meter grid sizes may be more suitable in those situations where the analysis of micro topography related to micro changes is critical for slope failures risk assessment or for the design of detailed drainage flow paths. The Terrestrial Laser Scanner (TLS has been proven to be an useful tool for such detailed field survey. In this work, we test the effectiveness of high resolution topography derived by airborne LiDAR and TLS for the recognition of areas subject to soil erosion risk in a typical terraced vineyard landscape of “Chianti Classico” (Tuscany, Italy. The algorithm proposed by Tarolli et al. (2013, for the automatic recognition of anthropic feature induced flow direction changes, has been tested. The results underline the effectiveness of LiDAR and TLS data in the analysis of soil erosion signatures in vineyards, and indicate the high resolution topography as a useful tool to

Adaptive restoration of river terrace vegetation through iterative experiments

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Dela Cruz, Michelle P.; Beauchamp, Vanessa B.; Shafroth, Patrick B.; Decker, Cheryl E.; O’Neil, Aviva

2014-01-01

Restoration projects can involve a high degree of uncertainty and risk, which can ultimately result in failure. An adaptive restoration approach can reduce uncertainty through controlled, replicated experiments designed to test specific hypotheses and alternative management approaches. Key components of adaptive restoration include willingness of project managers to accept the risk inherent in experimentation, interest of researchers, availability of funding for experimentation and monitoring, and ability to restore sites as iterative experiments where results from early efforts can inform the design of later phases. This paper highlights an ongoing adaptive restoration project at Zion National Park (ZNP), aimed at reducing the cover of exotic annual Bromus on riparian terraces, and revegetating these areas with native plant species. Rather than using a trial-and-error approach, ZNP staff partnered with academic, government, and private-sector collaborators to conduct small-scale experiments to explicitly address uncertainties concerning biomass removal of annual bromes, herbicide application rates and timing, and effective seeding methods for native species. Adaptive restoration has succeeded at ZNP because managers accept the risk inherent in experimentation and ZNP personnel are committed to continue these projects over a several-year period. Techniques that result in exotic annual Bromus removal and restoration of native plant species at ZNP can be used as a starting point for adaptive restoration projects elsewhere in the region.

Mapping the environmental risk potential on surface water of pesticide contamination in the Prosecco's vineyard terraced landscape

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Pizarro, Patricia; Ferrarese, Francesco; Loddo, Donato; Eugenio Pappalardo, Salvatore; Varotto, Mauro

2016-04-01

Intensive cropping systems today represent a paramount issue in terms of environmental impacts, since agricultural pollutants can constitute a potential threat to surface water, non-target organisms and aquatic ecosystems. Levels of pesticide concentrations in surface waters are indeed unquestionably correlated to crop and soil management practices at field-scale. Due to the numerous applications of pesticides required, orchards and vineyards can represent relevant non-point sources for pesticide contamination of water bodies, mainly prompted by soil erosion, surface runoff and spray drift. To reduce risks of pesticide contamination of surface water, the Directive 2009/128/CET imposed the local implementation of agricultural good practices and mitigation actions such as the use of vegetative buffer filter strips and hedgerows along river and pond banks. However, implementation of mitigation actions is often difficult, especially in extremely fragmented agricultural landscapes characterized by a complex territorial matrix set up on urban sprawling, frequent surface water bodies, important geomorphological processes and protected natural areas. Typically, such landscape matrix is well represented by the, Prosecco-DOCG vineyards area (NE of Italy, Province of Treviso) which lays on hogback hills of conglomerate, marls and sandstone that ranges between 50 and 500 m asl. Moreover such vineyards landscape is characterized by traditional and non-traditional agricultural terraces The general aim of this paper is to identify areas of surface water bodies with high potential risk of pesticide contamination from surrounding vineyards in the 735 ha of Lierza river basin (Refrontolo, TV), one of the most representative terraced landscape of the Prosecco-DOCG area. Specific aims are i) mapping terraced Prosecco-DOCG vineyards, ii) classifying potential risk from pesticide of the different areas. Remote sensing technologies such as four bands aerial photos (RGB+NIR) and Light

Two millennia of soil dynamics derived from ancient desert terraces using high resolution 3-D data

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Filin, Sagi; Arav, Reuma; Avni, Yoav

2017-04-01

Large areas in the arid southern Levant are dotted with ancient terrace-based agriculture systems which were irrigated by runoff harvesting techniques. They were constructed and maintained between the 3rd - 9th centuries AD and abandoned in the 10th century AD. During their 600 years of cultivation, these terraces documented the gradual aggradation of alluvial soils, erosion processes within the drainage basins, as well as flashflood damage. From their abandonment and onwards, they documented 1000 years and more of land degradation and soil erosion processes. Examination of these installations presents an opportunity to study natural and anthropogenic induced changes over almost two millennia. On a global scale, such an analysis is unique as it is rare to find intact manifestations of anthropogenic influences over such time-scales because of landscape dynamics. It is also rare to find a near millennia documentation of soil erosion processes. We study in this paper the aggradation processes within intact agriculture plots in the region surrounding the world heritage Roman-Byzantine ancient city of Avdat, Negev Highlands. We follow the complete cycle of the historical desert agriculture, from the configuration pre-dating the first anthropogenic intervention, through the centuries of cultivation, and up to the present erosion phase, which spans over more than a millennium. We use high resolution 3-D laser scans to document the erosion and the environmental dynamics during these two millennia. The high-resolution data is then utilized to compute siltation rates as well as erosion rates. The long-term measures of soil erosion and land degradation we present here significantly improve our understanding of the mechanism of long-term environmental change acting in arid environments. For sustainable desert inhabitation, the study offers insights into better planning of modern agriculture in similar zones as well as insights on strategies needed to protect such historical

Ground Water Modelling for the Restoration of Carex Communities on a Sandy River Terrace

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Andrzej Brandyk

2016-12-01

Full Text Available Management for sustainable river valleys requires balancing their natural values against the need for agricultural and recreational development on surrounding lands. The Southern Całowanie Peatland near the city of Warsaw sits on a sandy terrace and has well preserved Carex and Molinia stands existing in part of the area, especially where water tables are less than 1.5 m below the surface. The existing drainage network in this southern part has been poorly maintained and could be reestablished to help raise water levels for restoration of the peatland. Modflow was used to look at influence of drainage channel water levels on the overall water table height in the area. By raising water levels in the drainage system by 0.5 m it was found that 29% of the area would become suitable for increasing Carex and Molinia communities.

Linking bedrock exhumation, fluvial terraces, and geomorphic indices to constrain deformation rates at multiple timescales across the Himalayan deformation front in the Kashmir Himalaya, northwest India.

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Gavillot, Y. G.

2017-12-01

In Kashmir, the Himalayan Frontal thrust (HFT) is blind, characterized by a broad fold, the Suruin-Mastargh anticline, and displays no major emergent faults cutting either limb. A lack of knowledge of the rate of shortening and structural framework of the Suruin-Mastargh anticline hampers quantifying the earthquake potential for the deformation front. Our study combines bedrock exhumation, folded fluvial terraces, long-river profiles and river incision (specific stream power) analyses across the deformation front. At the core of the frontal fold, Apatite (U-Th)/He (AHe) cooling ages of detrital grains from the Siwalik foreland sediments indicate significant resetting. AHe data and thermal modeling reveal rapid cooling and exhumation initiated ca. 4 Ma for the deformation front, at least 3 Ma earlier than is indicated from previously available data. Exhumation rates over the last 1 m.y. and 4 m.y. range from 0.5 - 2.4 mm/yr, and 0.5 - 1 mm/yr, respectively. Four fluvial terraces yield multiple OSL and depth profiles Be10 TCN ages between 53 ka and 0.4 ka. Vector fold restoration of long terrace profiles, calculated specific stream power values, bedrock dip data, and stratigraphic thickness indicate a deformation pattern controlled by a duplex structure emplaced at depth along the basal décollement, folding the overlying roof thrust and foreland strata into a detachment-like fold. Dated terraces across the frontal fold yield rock uplift and shortening rates that range between 1.8-2.5 mm/yr, and 3.8-5.4 mm/yr, respectively, since 53 ka. Similarly, a balanced cross section yields a long-term shortening rate of 5mm mm/yr since 4 Ma. Geodetic data indicate that an 11-12 mm/yr arc-normal shortening rate characterizes the interseismic strain accumulation across the plate boundary due to India-Tibet convergence. These data combined with rates of other active internal faults in the Kashmir Himalaya indicate that shortening occurs roughly at an equal rate between folding at

Preliminary Data about Vertical Deformation of the eastern part of the Anatolian Scholle: Insight from Pülümür River Terraces

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Sançar, Taylan; Sunal, Gürsel; Korhan Erturaç, M.

2017-04-01

The northward motion of the African and Arabian plates relative to Eurasia and westward motion of the Anatolian scholle (An) have a key role in understanding of the eastern Mediterranean tectonics setting. The North and East Anatolian Shear Zones (NASZ and EASZ) present the main deformation zones of westward extrusion of the Anatolia whereas the NW-striking dextral and the NE-striking sinistral faults represent the remarkable intra-plate deformation within the An. In contrast to the earlier hypothesis, recent geologic and geodetic studies and micro seismic activity strongly suggests that internal deformation of the An is a continuous process. Some of these strike-slip faults, such as Tuzgölü Fault, Ecemiş Fault and Malatya-Ovacık Fault Zone (MOFZ), have long been documented in terms of the kinematic evolution, slip-rate and paleoseismic activity but there is no or very limited knowledge on the uplift characteristics of the An. In this study, we focused on more complex region of the An, which is delimited by the NASZ at north, the EASZ at southeast, the MOFZ at west and the Nazmiye Fault Zone (NFZ) at south. We present data on the distribution of geologic and morphologic structures by using satellite images, aerial stereo pairs, digital elevation models (DEM) with 10 m ground pixel resolution and extensive field observations in this region, particularly along the NFZ that has two sub-parallel segments. The horizontal deformation along the NFZ, within the eastern part of the An, represented by 20 m to 10 km horizontal displacements.The spatial distribution of terraces of the Pülümür River that is one of the biggest drainage systems of the region is a clear morphologic indicator of the vertical deformation of the eastern An. The Pülümür River incised into Paleozoic metamorphic basement at the north and Eocene volcanoclastic at the south. We mapped three terrace levels (T1-T3) in the V-shaped Pülümür River valley that has about 5 km offset along the both

The effect of lithology on valley width, terrace distribution, and coarse sediment provenance in a tectonically stable catchment with flat-lying stratigraphy

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Amanda Keen-Zebert,; Hudson, Mark R.; Stephanie L. Shepherd,; Evan A. Thaler,

2017-01-01

How rock resistance or erodibility affects fluvial landforms and processes is an outstanding question in geomorphology that has recently garnered attention owing to the recognition that the erosion rates of bedrock channels largely set the pace of landscape evolution. In this work, we evaluate valley width, terrace distribution, and sediment provenance in terms of reach scale variation in lithology in the study reach and discuss the implications for landscape evolution in a catchment with relatively flat2

Content of heavy metals in gleyic chernozem of Srem loess terrace under alfalfa

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Jakšić Snežana

2012-01-01

Full Text Available Production of high-quality forage from alfalfa is influenced not only by the presence of nutrients, but also by the absence of harmful elements, such as heavy metals. The examination of the total heavy metals content (Ni, Cr, Pb and As in gleyic chernozem soil of Srem loess terrace in Hrtkovci, under alfalfa (Medicago sativa L. were carried out in 2011 in order to determine suitability for the production of safe forage. It total content of Pb, As and Crwas below the maximum permitted concentrations. The content of As, Cr and Ni was higher in the surface layer, unlike Pb, whose content was higher in the deeper layers of soil. A significant positive correlation was found between the total content of Ni, Cr and As. An increased concentration of Ni was found, which was above the maximum permitted concentration. It is necessary to further control its content and accessibility examination and extraction from plants, to prevent its entry into the food chain and provide safe food.

Sea level high stand in Marine Isotope Stage 5e: evidence from coral terraces in Sumba Island, Indonesia

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LU, Y.; Rigaud, S.; Leclerc, F.; Liu, X.; Chiang, H. W.; Djamil, Y. S.; Meilano, I.; Bijaksana, S.; Abidin, H. Z.; Tapponnier, P.; Wang, X.

2017-12-01

Uplifted coral reef terraces, possibly spanning the last one million years, are extensively exposed along the northern coast of Sumba Island, Indonesia. We collected a suite of fossil coral samples from the inner edges of terraces at Cape Laundi to study past sea level change, particularly that during the marine isotope stage 5e. These samples were dated by the high-precision U/Th disequilibrium dating methods. For those with δ234U-initial values beyond the range of 145±7‰[1,2] , the open-system model by Thompson et al. [3] was then applied to correct their ages. Only less than 20% of the samples could not derive reasonable ages after the correction, and their abnormally high δ234U-initial values (> 180‰) seem to suggest a limitation of open-system correction with the current model. After the correction of long-term uplift rate of 0.3 mm/kyr, we found that the relative sea level at Cape Laundi, Sumba was 7 m during MIS5e and then dropped to -20 m during the MIS5a and 5c. More importantly, our results indicate that sea level reached a high stand at 129±0.6 ka, supported by both U/Th dates on pristine corals and open-system model corrected ages. In line with the sea level reconstruction from western Australia, our results do not support a second and higher sea level during MIS5e. Moreover, there is no significant lead or lag between the timing of sea level high stand in Sumba and the peak of Northern Hemisphere summer insolation. 1. Robinson et al. (2004) Science. 305: 851-854 2. Cheng et al. (2013) Earth and Planetary Science Letters. 371-372: 82-91 3. Thompson et al. (2003) Earth and Planetary Science Letters. 210: 365-381

Moa fossils and chronology of a Pleistocene terrace sequence, Tauweru, Wairarapa, New Zealand

International Nuclear Information System (INIS)

Collen, J.D.; Grapes, R.H.; Eager, S.H.

2000-01-01

The fortuitous preservation of bones of the medium-sized moa Euryapteryx geranoides (Owen) in Pleistocene colluvial sediments near Tauweru, Wairarapa, has allowed radiocarbon dating of a terrace sequence along the lower Tauweru River. The bones were in a shelly, conglomeratic sandstone on an erosion surface cut into mid-Pliocene (Waipipian) siltstone, and were overlain by loess and situated immediately adjacent to onlapping fluvial gravels. Most of the bones are from a single skeleton buried articulated and apparently nearly complete, and there is also a single left tibiotarsus from a slightly larger bird. Bone from the right femur gave a radiocarbon age of 14 262 +/- 87 yr BP by accelerator mass spectrometry. The material was slightly chalky and had a low collagen yield with a relatively large amount of humic material; contamination which would lower the measured age is thus possible. However, an amino acid profile characteristic of collagen makes it unlikely that high contaminant levels are present. The radiocarbon age for the bone is likely to be 14-18 ka (16-22 000 cal. yr) or possibly older, with the lower limit being set by the radiocarbon age and the upper limit inferred from the amount of humic contamination. This is thus the oldest moa skeleton reported from Wairarapa. Loess overlying the bones contains disseminated shards of clear rhyolitic glass with a composition identical to that of the 22.6 ka (24 500 cal. yr) Kawakawa Tephra, and gave an age by optical dating of 26 +/- 2 ka. A thicker tephra deposit within loess on a higher, deeply dissected surface may also be partly reworked; optical dating of a sample of loess from 2 m beneath it gave an age of 22 +/- 2 ka. Thermoluminescence dating of two samples of the conglomeratic deposits surrounding the bones gave ages of 52 +/- 13.2 and 102 +/- 18 ka, respectively, indicating redeposition of these sediments without resetting of the thermoluminescence signal. One of these samples was also dated by optical

The impact of agriculture terraces on soil organic matter, aggregate stability, water repellency and bulk density. A study in abandoned and active farms in the Sierra de Enguera, Eastern Spain.

Science.gov (United States)

Cerdà, Artemi; Burguet, Maria; Keesstra, Saskia; Prosdocimi, Massimo; Di Prima, Simone; Brevik, Erik; Novara, Agata; Jordan, Antonio; Tarolli, Paolo

2016-04-01

Soil erosion, land degradation, lack of organic matter, erodible soils, rock outcrops… are a consequence of the human abuse and misuse of the soil resources. And this is a worldwide environmental issue (Novara et al., 2011; Vanlauwe et al., 2015; Musinguzi et al., 2015; Pereira et al., 2015; Mwagno et al., 2016). Agriculture terraces are a strategy to reduce the soil erosion, improve the soil fertility and allow the ploughing (Cerdà et al., 2010; Li et al., 2014). Although this idea is well accepted there are few scientific evidences that demonstrate that soils in the terraced areas are more stable, fertile and sustainable that the soil in non terraced areas. In fact, the ploughing in comparison to the abandoned or not ploughed land results in the soil degradation (Lieskovský and Kenderessy, 2014; Gao et al., 2015; Parras-Alcántara et al., 2014). This is mainly due to the lack of vegetation that increase the surface runoff (Cerdà et al., 1998; Keesstra et al., 2007). And why is necessary to develop also in terraced landscapes soil erosion control strategies (Mekonnen et al., 2015a; Mekonnen et al., 2015b; Prosdocimi et al., 2016). Our objective was to assess the soil organic matter content (Walkley and Black, 1934), the soil bulk density (ring method), the aggregate stabilility (drop impact) and the water repellency (Water Drop Penetration Time test) in four study sites in the Sierra de Enguera. Two sites were terraced: one abandoned 40 years before the measurements and the other still active with olive crops. And two control sites non-terraced. We used the paired plot strategy to compare the impact of terracing and abandonment. At each site we collected randomly 50 soil samples at 0-2 cm, 4-6 and 8-10 cm depth. At each sampling point 100 WDPT measurements where carried out, and one sample for the bulk density, and one for the organic matter, and one for the soil aggregate stability were collected. The soil surface samples shown the largest differences. The

Terraced-heterostructure large-optical-cavity AlGaAs diode laser - A new type of high-power CW single-mode device

Science.gov (United States)

Botez, D.; Connolly, J. C.

1982-01-01

A new terraced lateral wave confining structure is obtained by liquid phase epitaxy over channeled substrates misoriented perpendicular to the channels' direction. Single spatial and longitudinal mode CW operation is achieved to 50 mW from one facet, in large spot sizes (2 x 7.5 micron, 1/e squared points in intensity) and narrow beams (6 deg x 23 deg), full width half-power). At 70 C ambient temperature CW lasing is obtained to 15 mW from one facet. Weak mode confinement in an asymmetric lateral waveguides provides discrimination against high-order mode oscillation.

Reconhecimento de unidades deposicionais de média e baixa encosta no município de Lapa (PR por meio da construção de topossequências / The recognition of deposit units in the low and medium terraces in Lapa (PR, Brazil through the construction of toposequences

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Melina Mara de Souza

2009-08-01

Full Text Available ResumoA construção de topossequências para reconhecimento de unidades deposicionais de média e baixa encosta no município de Lapa (PR foi usada para identificar as propriedades morfológicas, texturais e de estrutura interna dos depósitos de média e baixa encosta com vistas ao reconhecimento e seu significado paleoidrológico. A metodologia consistiu em levantamento topográfico de encosta, sondagens com trado holandês, descrição em campo dos materiais sedimentares, pedológico e paleopedológico que recobrem a encosta, análise do teor de matéria orgânica e construção de topossequências para reconhecimento da distribuição espacial destes materiais sobre a encosta. Foram construídas dez topossequências que resultaram na identificação das unidades sedimentares e pedológicas que formam a encosta e na identificação da sua distribuição tridimensional. Nas porções de média e baixa encosta da área foram identificados, além dos diferentes tipos de rocha, três horizontes-organo-minerais soterrados, três unidades alúvio-coluviais e duas aluviais. Os três horizontes organo-minerais auxiliaram na definição da estratigrafia local. A análise das propriedades dos depósitos que recobrem a média e baixa encosta colocou em evidência processos aluviais como dominantes na deposição das unidades sedimentares.AbstractThe construction of topo-sequences for the identification of deposit units at low and medium terraces in Lapa (PR was used to verify the morphology, texture and internal structure properties of the low and medium terraces in order to establish their paleo-hydrological meaning. The methodology consisted in a topographic survey of the terraces, sampling with a Dutch auger, field description of the sedimentary, pedological and paleopedological materials which occur in the terraces, analysis of the organic content, and construction of the topo-sequences for identification of the spatial distribution of these

Temporal dynamics of plant succession in abandoned field in Mediterranean mountain areas: farming terraces and sloping fields (Iberian System, Spain)

Science.gov (United States)

Nadal-Romero, Estela; Errea, Paz; Lasanta, Teodoro

2017-04-01

Cropland abandonment is an important problem in mountain areas worldwide. This process represents the change from an agricultural management to an abandoned land in which a complex plant succession process occurs, with important hydromorphological effects, and consequences in water resources availability and soil erosion. Literature indicates that plant succession depends on multiple natural factors (soil properties, topography, climate, lithology, and distance to natural covers…) and anthropogenic factors (age of abandonment, management of each field during the cultivation period and after the abandonment…). Despite the advances, much is unknown about the vegetation succession, due to the complexity of ecological and social conditions in which land abandonment occurs. Recently, it is shown that only local factors can explain the heterogeneity of the process (Burel and Baudry, 2002; Jouba and Alados, 2012). In this work, we analyze the diversity of vegetation cover in abandonment fields in Cameros Viejo (Iberian System, Spain), related to the different field patterns (terraces and sloping fields) and the age of abandonment. Agricultural lands were delimited using aerial photographs from 1956 and 1978. The current land cover was obtained from SIOSE (Information System of Land Occupation in Spain). According to our cartography, cultivated land occupied as much as 15,491 ha (39% of the area), remaining abandoned 14,505 ha by 1978. Farming terraces occupied 55.9% of the abandoned area, and 44.1% as sloping fields. On the other hand, our cartography highlights the complexity of current land cover of abandoned fields in a landscape matrix of scrubland. Our results suggest that ecological succession is faster in farming terraces than in sloping fields, mostly until scrubland phase is attained. They also suggest that current land cover is better explained by the physical conditions of each field than by the abandonment age. Acknowledgement This research was supported

Nano-structure and optical properties (plasmonic) of graded helical square tower-like (terraced) Mn sculptured thin films

Energy Technology Data Exchange (ETDEWEB)

Savaloni, Hadi, E-mail: savaloni@khayam.ut.ac.ir [Department of Physics, University of Tehran, North-Kargar Street, Tehran (Iran, Islamic Republic of); Fakharpour, Mahsa [Department of Physics, Islamic Azad University, Science and Research Branch, Tehran (Iran, Islamic Republic of); Siabi-Garjan, Araz [Department of Advanced Technologies, University of Mohaghegh Ardabili, Namin, Ardabil (Iran, Islamic Republic of); Department of Materials Engineering and Nanotechnology, Sabalan University of Advanced Technologies (SUAT), Namin (Iran, Islamic Republic of); Placido, Frank [SUPA and Institute of Thin Films, Sensors and Imaging, University of The West of Scotland, High Street, Paisley (United Kingdom); Babaei, Ferydon [Department of Physics, University of Qom, Qom (Iran, Islamic Republic of)

2017-01-30

Highlights: • Graded helical square tower-like terraced sculptured Mn thin films are produced with different number of arms. • XRD, AFM, FESEM and optical analyses as well as theoretical calculations are carried out. • Intensity of Plasmon peaks depend on the polarization, the incident angle, and the distance from the shadowing block. • The presence of defects in these sculptured structures can be predicted by theoretical investigation. • Experimental and theoretical investigations show consistent results. - Abstract: Graded helical square tower-like terraced sculptured Mn thin films (GHSTTS) are produced in three stages with different number of arms using oblique angle deposition together with rotation of substrate holder about its surface normal, plus a shadowing block fixed at the centre of the substrate holder. The structural characterization of the produced samples was obtained using field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). Results showed a structural gradient with distance from the edge of the shadowing block, which in turn is responsible for the decrease in the volume of void fraction and increase of grain size. Plasmon absorption peaks observed in the optical analysis of these nano-structures showed that their wavelength region and intensity depend on the polarization and the incident angle of light, as well as the distance from the edge of the shadowing block. According to our model and discrete dipole approximation (DDA) calculations, when the number of parallel nano-rods of different lengths and radii are increased the peak in the spectrum shifts to shorter wavelengths (blue shift). Also when the diameters of the nano-rods increases (a situation that occurs with increasing film thickness) the results is again a blue shift in the spectrum. The presence of defects in these sculptured structures caused by the shadowing effect is predicted by the theoretical DDA investigation of their optical spectra

Exposure to secondhand smoke in terraces and other outdoor areas of hospitality venues in eight European countries.

Science.gov (United States)

López, Maria J; Fernández, Esteve; Gorini, Giuseppe; Moshammer, Hanns; Polanska, Kinga; Clancy, Luke; Dautzenberg, Bertrand; Delrieu, Agnes; Invernizzi, Giovanni; Muñoz, Glòria; Precioso, Jose; Ruprecht, Ario; Stansty, Peter; Hanke, Wojciech; Nebot, Manel

2012-01-01

Outdoor secondhand smoke (SHS) concentrations are usually lower than indoor concentrations, yet some studies have shown that outdoor SHS levels could be comparable to indoor levels under specific conditions. The main objectives of this study were to assess levels of SHS exposure in terraces and other outdoor areas of hospitality venues and to evaluate their potential displacement to adjacent indoor areas. Nicotine and respirable particles (PM2.5) were measured in outdoor and indoor areas of hospitality venues of 8 European countries. Hospitality venues of the study included night bars, restaurants and bars. The fieldwork was carried out between March 2009 and March 2011. We gathered 170 nicotine and 142 PM2.5 measurements during the study. The median indoor SHS concentration was significantly higher in venues where smoking was allowed (nicotine 3.69 µg/m3, PM2.5: 120.51 µg/m3) than in those where smoking was banned (nicotine: 0.48 µg/m3, PM2.5: 36.90 µg/m3). The median outdoor nicotine concentration was higher in places where indoor smoking was banned (1.56 µg/m3) than in venues where smoking was allowed (0.31 µg/m3). Among the different types of outdoor areas, the highest median outdoor SHS levels (nicotine: 4.23 µg/m3, PM2.5: 43.64 µg/m3) were found in the semi-closed outdoor areas of venues where indoor smoking was banned. Banning indoor smoking seems to displace SHS exposure to adjacent outdoor areas. Furthermore, indoor settings where smoking is banned but which have a semi-closed outdoor area have higher levels of SHS than those with open outdoor areas, possibly indicating that SHS also drifts from outdoors to indoors. Current legislation restricting indoor SHS levels seems to be insufficient to protect hospitality workers--and patrons--from SHS exposure. Tobacco-free legislation should take these results into account and consider restrictions in the terraces of some hospitality venues to ensure effective protection.

New data on the chronology of the Vale do Forno sedimentary sequence (Lower Tejo River terrace staircase) and its relevance as a fluvial archive of the Middle Pleistocene in western Iberia

DEFF Research Database (Denmark)

Cunha, Pedro; Martins, Antonio; Buylaert, Jan-Pieter

2017-01-01

The Vale do Forno archaeological sites (Alpiarça, central Portugal) document the earliest human occupation in the Lower Tejo River, well established in geomorphological and environmental terms, within the Middle Pleistocene. In a staircase of six fluvial terraces, the Palaeolithic sites were found...

The Improvement of the Ventilation System in the Existing Terraced Houses in Malaysia

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Arab Yasser

2016-01-01

Full Text Available This study aims to find a sustainable solution in order to reduce the indoor temperature in hot and humid climate such as Malaysia. The focus of this study is to create a new device (Air Tube which is considered to be a remedial device for the indoor spaces, and can be installed for the existed houses. The method of this study is to design the Air Tube device and install is in the rooms of second floor in semi-detached and terrace house in order to reduce the temperature few degrees. The study will depend on taking manual measurements in the site and making simulation using computer software Ecotect on 14th of February (which considered to be the hottest day in the year and trying to find the best solution to reduce the temperature in such hot and humid weather, the case study is a semi-detach house with post-modern architectural style, which is located in Sungai Petani, Kedah, Malaysia. The research finds that AirTubeis a good solution for the existed houses to decrease the temperature and reach the thermal comfortable atmosphere.

Weathering rind formation in buried terrace cobbles during periods of up to 300ka

International Nuclear Information System (INIS)

Yoshida, H.; Metcalfe, R.; Nishimoto, S.; Yamamoto, H.; Katsuta, N.

2011-01-01

Highlights: → Weathering rinds in sandstone and basalt cobbles buried for up to 300 ka have been investigated. → The aim was to determine the formation process and elemental mass balances during rind development. → Elemental mass balances across the rinds were determined by using open system mass balance (τ i,j ) calculations. → The formation rates are slower than the tropical areas due to the lower rainfall in the studied area. - Abstract: Weathering rinds formed in Mesozoic sandstone and basalt cobbles buried in terrace deposits for up to 300 ka have been investigated. The aim was to determine the formation process and elemental mass balances during rind development. The ages of terraces distributed in the western part of Fukui prefecture, central Japan have been determined as 50 ka, 120 ka and 300 ka based on a tephro-stratigraphic method. Detailed investigations across the weathering rinds, consisting of microscopic observations, porosity measurements, and mineralogical and geochemical analyses using X-ray diffractometry (XRD), X-ray fluorescence (XRF), secondary X-ray analytical microscopy (SXAM), scanning electron microanalyser (SEM) and electron probe microanalysis (EPMA) have been carried out. The results revealed that the Fe concentrations in the weathering rind of a basalt cobble slightly decreased from the cobble's surface (rim) towards the unweathered core. In contrast, in a sandstone cobble formed under the same environmental conditions over the same period of time there is an Fe-rich layer at some distance below the cobble's surface. Elemental mass balances across the rinds were determined by using open system mass balance (τ i,j ) calculations and show that the Fe was precipitated as Fe-oxyhydroxides in the basalt cobbles, although Fe was slightly removed from the rims. In sandstone cobbles, on the other hand, Fe migrated along a Fe concentration gradient by diffusion and precipitated as Fe-oxyhydroxide minerals to form the weathering rinds

Study on the estimation method of uplift during the late Quaternary by using river terraces (3). Tectonic movement described by last 100,000 years uplift distribution in an inland area

International Nuclear Information System (INIS)

Hataya, Ryuta

2006-01-01

Uplift for the last 100,000 years, which is estimated in both side of the Ayashi fault in Miyagi prefecture and the Sekiya fault in Tochigi Prefecture by using the relative height of river terraces is almost equal to vertical displacements of these faults for the last 100,000 years. Hence, the method using fluvial terraces is available for estimating the uplift for the last 100,000 years in an inland area quantatively. Furthermore, significance of the uplift obtained by the proposed methodology in this study is emphasized. It is possible to find the geotectonic feature that were so far overlooked as deformed zones along active fault, tectonic style of uplift and subsidence by obtaining the 3-dimensional distribution of uplift in last 100,000 years. Methodology and concept proposed in this study give practical survey method of late Quaternary 3-dimensional uplift characteristics for the long-term safety of geological disposal of high-level radioactive waste. By applying this method to Quaternary research, new insights on the Quaternary tectonic movement may be given. (author)

Occurrence of 1 ka-old corals on an uplifted reef terrace in west Luzon, Philippines: Implications for a prehistoric extreme wave event in the South China Sea region

Science.gov (United States)

Ramos, Noelynna T.; Maxwell, Kathrine V.; Tsutsumi, Hiroyuki; Chou, Yu-Chen; Duan, Fucai; Shen, Chuan-Chou; Satake, Kenji

2017-12-01

Recent 230Th dating of fossil corals in west Luzon has provided new insights on the emergence of late Quaternary marine terraces that fringe west Luzon Island facing the Manila Trench. Apart from regional sea level changes, accumulated uplift from aseismic and seismic processes may have influenced the emergence of sea level indicators such as coral terraces and notches. Varied elevations of middle-to-late Holocene coral terraces along the west Luzon coasts reveal the differential uplift that is probably associated with the movement of local onland faults or upper-plate structures across the Manila Trench forearc basin. In Badoc Island, offshore west of Luzon mainland, we found notably young fossil corals, dated at 945.1 ± 4.6 years BP and 903.1 ± 3.9 years BP, on top of a 5-m-high reef platform. To constrain the mechanism of emergence or emplacement of these fossil corals, we use field geomorphic data and wave inundation models to constrain an extreme wave event that affected west Luzon about 1000 years ago. Our preliminary tectonic and tsunami models show that a megathrust rupture will likely lead to subsidence of a large part of the west Luzon coast, while permanent coastal uplift is attributed to an offshore upper-plate rupture in the northern Manila Trench forearc region. The modeled source fault ruptures and tsunami lead to a maximum wave height of more than 3 m and inundation distance as far as 2 km along the coasts of western and northern Luzon. While emplacement of coral boulders by an unusually strong typhoon is also likely, modeled storm surge heights along west Luzon do not exceed 2 m even with Typhoon Haiyan characteristics. Whether tsunami or unusually strong typhoon, the occurrence of a prehistoric extreme wave event in west Luzon remains an important issue in future studies of coastal hazards in the South China Sea region.

Modelo para o dimensionamento e a locação de sistemas de terraceamento em nível Model to design level terracing systems

Directory of Open Access Journals (Sweden)

Nori P. Griebeler

2005-12-01

Full Text Available A erosão hídrica é um dos principais causadores da degradação das terras agrícolas, provocando expressivos prejuízos à sociedade. Em virtude desses danos, torna-se fundamental o desenvolvimento de técnicas que permitam o aumento da eficiência das práticas para a conservação do solo. Com esse objetivo, desenvolveu-se um modelo para o dimensionamento e a locação de sistemas de terraceamento em nível, utilizando modelos digitais de elevação do terreno gerados em sistemas de informações geográficas (SIG. A fim de possibilitar a aplicação do modelo desenvolvido, elaborou-se um software que permite a realização das interações necessárias para o dimensionamento do sistema. Os resultados obtidos mostram que o modelo oferece a vantagem de permitir o dimensionamento de cada terraço, considerando as condições existentes na área específica que irá contribuir com o escoamento superficial para o mesmo. A outra vantagem do modelo desenvolvido está na possibilidade de realização de simulações, permitindo a observação e o acompanhamento, de maneira fácil e objetiva, das mudanças provocadas no sistema de terraceamento, em função da alteração nas características de uso e manejo do solo.Water erosion is one of the main problems of agricultural lands degradation, causing largess damages to the society. Because of these damages, it becomes necessary the development of techniques that allow the increase of the efficiency of soil conservation practices. With this objective, a model was developed for design and location of level terracing systems using digital models of elevation of the land generated in geographic information systems (GIS. In order to facilitate the application of the developed model, it was elaborated a software. The results show that the model offers as the principal advantage the design of each terrace considering the existent conditions in the specific area that will contribute with the runoff to

Radiogenic 3He/4He Estimates and Their Effect on Calculating Plio-Pleistocene Cosmogenic 3He Ages of Alluvial-Fan Terraces in the Lower Colorado River Basin, USA

Science.gov (United States)

Fenton, C.; Pelletier, J.

2005-12-01

Several alluvial-fan terraces near Topock, AZ were created by successive entrenchment of Pliocene and Pleistocene alluvial-fan gravels shed from the adjacent Black Mountains along the lower Colorado River corridor below Hoover Dam. These fans interfinger with and overlie main-stem Colorado River sands and gravels and grade to terrace levels that correspond with pre-existing elevations of the Colorado River. Absolute dates for the ages of Quaternary deposits on the lower Colorado River are rare and cosmogenic 3He age estimates of these surfaces would help constrain the timing of aggradation and incision in the lower Colorado River corridor. We analyzed individual basalt boulders from several terrace surfaces for total 3He/4He concentrations to calculate cosmogenic 3He ages of each fan terrace; 3He/4He values, expressed as R/Ra where Ra is the 3He/4He of air, range from 0.29 to 590. Black Mountain volcanic rocks have reported K-Ar ages between 15 and 30 Ma and basalt samples from adjacent alluvial fans contain 0.42 to 47× 1012 at/g of 4He, which has likely accumulated due to nuclear processes. The amount of radiogenic 3He/4He can be significant in old rocks with young exposure ages and can complicate determination of cosmogenic 3 He content. Alpha-decay of U, Th, and their daughter isotopes produces large amounts of 4He, whereas significant amounts of radiogenic 3He are only produced through the neutron bombardment of Li and subsequent beta-decay of tritium. We measured Li, U, Th, major and rare-earth element concentrations in whole-rock basalts and mineral separates. These concentrations are used to estimate the ratio of radiogenic helium contributed to the total helium system in our samples. Li concentrations typically range from 6 to 17 ppm, with one outlier of 62 ppm. U contents range from calculations predict that the average radiogenic helium (R/Ra) contributed to the total helium in Black Mountain basalt samples is 0.011. Other noble gas studies have shown

Potencial econômico da utilização de micro-terraceamento em lavouras de café: um estudo de caso = Economic potential of using micro-terracing in coffee farming: a case study

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Ednaldo Lino Alves

2017-01-01

Full Text Available Dentre os principais problemas enfrentados pela cafeicultura de montanha atualmente está o alto custo de produção, decisivamente influenciado pela escassez e elevado custo de mão de obra. Este trabalho objetivou realizar uma análise de viabilidade econômica na utilização de micro-terraceamento em lavouras de café do interior paulista. O estudo comparou os custos de produção em dois sistemas: semi mecanizado (micro-terraceamento e manual, em um período de 10 anos. Os dados foram coletados em uma propriedade rural no município de São Sebastião da Grama, São Paulo, em uma área de 12 ha, já implantada e em produção. Para as receitas foi considerado o valor da saca de 60 kg de café arábica beneficiado a R$ 410,00. Os indicadores financeiros utilizados foram: Valor Presente Líquido [VPL], Taxa Interna de Retorno [TIR] e payback descontado. O micro-terraceamento se apresenta como alternativa economicamente viável; o fluxo de caixa do projeto demonstra valores de VPL positivos utilizando taxas mínimas de atratividade variando de 6% a 20%; TIR de 41% e Payback descontado de dois anos. A maior contribuição para a redução do custo de produção do terreno terraceado é do item orçamentário mão de obra, tanto nos tratos culturais quanto na colheita. O fluxo de caixa considerando a área micro-terraceada é positivo e superior ao da área comparada. = Among the main problems faced by mountain coffee is currently the high cost of the production, decisively influenced by the scarcity and high cost of manpower. This study aimed to conduct an economic feasibility study of the use of "micro-terracing" in coffee crop at São Paulo. The study compared the costs of production in two systems: semi-mechanized (micro-terracing and manual, in a period of 10 years. Data were collected on a farm in the city of São Sebastião da Grama, São Paulo, in an area of 12 ha, already deployed and in production. For the computation of the revenues

Storm-related sedimentation influenced by coastal configuration in the stratigraphic record of a tectonically active shelf (Upper Pleistocene Le Castella terrace, Italy)

Science.gov (United States)

Nalin, Ronald; Massari, Francesco

2018-03-01

Analysis of patterns of coastal circulation and sediment dispersal is an essential step for the study of controlling factors influencing the long-term dynamics of coastal systems. Modern settings offer the possibility to monitor relevant parameters over relatively short time spans. However, geological examples complement this perspective by providing a time-averaged record where longer trends and stratigraphically significant processes can be evaluated. This study investigates the shallow marine deposits of Le Castella terrace (Upper Pleistocene, southern Italy) to document how patterns of circulation influenced by coastline configuration can affect the preserved millennial-scale depositional record of a progradational shoreline system. The regressive portion of the Le Castella terrace deposits, developed during a relative sea-level highstand and falling stage, consists of a progradational wedge mainly composed of redistributed skeletal particles of a coeval shallow water carbonate factory. Preservation of the morphology of the paleocoastline and abundant current-related sedimentary structures allow reconstruction of the predominant sediment dispersal dynamics responsible for the formation of this sedimentary wedge. Facies and paleocurrent analysis indicate offshore and alongshore sediment transport modes, consistent with coastal circulation driven by storms normally incident to the shoreline and a sharp change in coastline orientation. This coastal inflection influenced circulation patterns causing flow separation and eddy formation in the lee of the curved coastline. Syndepositional tectonic deformation also affected the architecture of the preserved deposits, controlling the nucleation and development of a clinostratified body and determining localized lateral stratigraphic variability. This study illustrates how transient but recurrent circulation patterns associated with changes in coastal orientation and related to high-energy storm events can leave a

Reduced step edges on rutile TiO (110) as competing defects to oxygen vacancies on the terraces and reactive sites for ethanol dissociation

DEFF Research Database (Denmark)

Martinez, U.; Hansen, Jonas Ørbæk; Salazar, Estephania Lira

2012-01-01

microscopy studies, we here present experimental evidence for the existence of O vacancies along the ⟨11̅ 1⟩R step edges (OS vac.’s) on rutile TiO2(110). Both the distribution of bridging O vacancies on the terraces and temperature-programed reaction experiments of ethanol-covered TiO2(110) point...... to the existence of the OS vac.’s. Based on experiments and density functional theory calculations, we show that OS vac.’s are reactive sites for ethanol dissociation via O-H bond scission. Implications of these findings are discussed...

The mass balance of soil evolution on late Quaternary marine terraces, northern California

Science.gov (United States)

Merritts, Dorothy J.; Chadwick, Oliver A.; Hendricks, David M.; Brimhall, George H.; Lewis, Christopher J.

1992-01-01

Mass-balance interpretation of a soil chronosequence provides a means of quantifying elemental addition, removal, and transformation that occur in soils from a flight of marine terraces in northern California. Six soil profiles that range in age from several to 240,000 yr are developed in unconsolidated, sandy-marine, and eolian parent material deposited on bedrock marine platforms. Soil evolution is dominated by (1) open-system depletion of Si, Ca, Mg, K, and Na; (2) open-system enrichment of P in surface soil horizons; (3) relative immobility of Fe and Al; and (4) transformation of Fe, Si, and Al in the parent material to secondary clay minerals and sesquioxides. Net mass losses of bases and Si are generally uniform with depth and substantial, in some cases approaching 100 percent; however, the rate of loss of each element differs markedly, causing the ranking of each by relative abundance to shift with time. Loss of Si from the sand fraction by dissolution and particle-size diminution, from about 100 percent to less than 35 percent over 240 ky, mirrors a similar gain in the silt and clay size fractions. The Fe originally present in the sand fraction decreases from greater than 80 percent to less than 10 percent, whereas the amount of Fe present in the clay and crystalline oxyhydroxide fractions increases to 25 percent and 70 percent, respectively.

Refurbishment of a Victorian terraced house for energy efficiency

Science.gov (United States)

Dimitriou, Angeliki

The impacts of global warming are now obvious. The international community has committed itself to reduce CO2 emissions, the main contributor to the greenhouse effect, both at international and national levels. In the Kyoto Protocol signed in 1997, countries have committed to reduce their greenhouse gases emissions below their 1990 levels by the period 2008-2012. The UK specifically should reduce those emissions by 12.5%. Format reason, the UK has introduced a package of policies, which promote not only the use of renewable energy resources, but most importantly the reduction in energy use, with energy efficiency. Refurbishment of existing houses has and will contribute to the reduction of energy consumption. A Victorian mid-terraced house was studied in this report, and different refurbishment measures were tested, using two software programmes: TAS and SAP. The targets were to achieve certain levels of thermal comfort, to comply with the Building Regulation for building thermal elements and to achieve a high SAP rating. Then, the cost of each measure was calculated and its CO2 emissions were compared. Heat losses were mainly through the walls and roof. Roof and mainly wall refurbishment measures reduce the heating loads the most. Ground floor insulation does not contribute to the reduction of the heating loads, on the contrary it has detrimental effect in summer, where the cooling effect coming from the ground is being reduced. Window replacement achieves a very good performance in summer resulting in the reduction of overheating. Wall and roof insulation increase the SAP rating the most, between the building elements, but boiler replacement and upgrading of heating controls increase it more. According to the SAP rating, CO2 annual emissions are reduced the most by boiler replacement and then by wall and roof. The results given by the two softwares concerning which measure is more leads more to energy efficiency, are the same. Finally, if the measures which lead

Land Use Alters the Plant-Derived Carbon and Nitrogen Pools in Terraced Rice Paddies in a Mountain Village

Directory of Open Access Journals (Sweden)

Seiji Shimoda

2017-10-01

Full Text Available In Japan, terraced paddies in mountain villages are symbolic of the traditional landscape, but they are gradually being abandoned. To compare plant-derived C and N among land uses, we compared adjacent forest floor (FF, agricultural paddy (AP, and post-agricultural paddy (PP sites. Long-term litter accumulation could explain the significantly higher litter C and belowground biomass C in FF than in AP and PP. The low-density-fraction (LF soil C was significantly higher in FF than in PP and better reflected land use than the whole-soil C. The AP soil held more N than FF and PP at 20–30 cm, associated with higher LF soil N. Periodic tillage in AP maintains the LF soil N, but N supplied to the surface soil reduced with depth following abandonment. Differences in recycling of organic matter and nutrients among land uses are crucial to plant-derived C and N contents of soil.

The Tarawera eruption, Lake Rotomahana, and the origin of the Pink and White Terraces

Science.gov (United States)

Keam, Ronald F.

2016-03-01

This chapter introduces the historical and geographical background for the scientific studies at Tarawera and Lake Rotomahana in the Taupo Volcanic Zone of New Zealand as detailed in this Special Issue of the Journal of Volcanology and Geothermal Research. It also presents the results of some original investigations. These are based partly on the large body of historical information that exists about the 1886 Tarawera eruption and the geothermal system at Rotomahana, and partly on the results of dedicated geological studies by other researchers within the Okataina Volcanic Centre where the historical events took place. Specifically, the new material here presented includes a detailed analysis of a previously almost neglected narrative by the only observer to witness the 1886 eruption from the southeast of the erupting craters and leave an account of his observations. The importance of a co-operative interplay between pre-existing tectonic deformation and its responses to strong seismic activity induced by magmatic intrusion is emphasised as being a major determinant in the course of the eruption, and as the main trigger of the eruption explosions that were audible throughout half of the land area of New Zealand. The chapter then concentrates on showing how the recent geological studies, in conjunction with ideas on the architecture of geysers, permit an explanation to be given as to how the unique Pink and White Terraces came to be formed.

Forest gardening on abandoned terraces links local biomass carbon accumulation to international carbon markets, reverses land degradation, improves food diversity, and increases farmer income

Science.gov (United States)

Schmidt, Hans-Peter; Pandit, Bishnu Hari; Kammann, Claudia

2017-04-01

Despite chronic underproduction of food in Nepal, more and more agricultural land is abandoned especially in the remote middle hills and mountains. Male and young workers leave the villages for higher wages in the bigger cities or abroad. By now, most villages are mainly populated by women, children and elderly persons maintaining the gardens and fields close to the houses and leave the centenarian terraces fallow. Erosion, vanishing water resources, losses of soil organic carbon and the weakening of the local agro-economy become increasingly problematic. During the rainy season of 2015/16, 86 farmer families from four villages replanted their abandoned terraces with 25,000 mixed trees, mostly Cinnamon, Moringa, Mulberry, Lemon, Michelia, Paulownia, and various nuts. All trees were planted with a blend of organic biochar-based fertilizer and compost, since it was convincingly demonstrated by more than 20 field trials in this region that this was the most plant-growth promoting method. Mulching of the trees with rice straw or thatch grass was generalized. To let the young tries pass the critical seven months of dry season, water retention ponds with pipe irrigation were installed. Farmers were organized in groups of three families to mutually help and control the tree maintenance which led to an average tree survival rate of more than 80% after the first year compared to less than 50% in many country-wide forestation projects since the 1980s. Between the lower and upper lines of trees on the terraces, ginger, turmeric, black beans, onions, lentils and other secondary crops were cultivated using the same organic biochar based fertilizer and mulching techniques. What may seem a reasonable approach for many places, is in many of the poorest countries simply not possible to realize because village families do often not have the necessary initial investment for saplings and irrigation facilities at their disposal. Therefore, the Ithaka Institute linked the forest garden

New constraints on slip rates of the Fodongmiao-Hongyazi fault in the Northern Qilian Shan, NE Tibet, from the 10Be exposure dating of offset terraces

Science.gov (United States)

Yang, Haibo; Yang, Xiaoping; Huang, Xiongnan; Li, An; Huang, Weiliang; Zhang, Ling

2018-01-01

The Fodongmo-Hongyazi fault (FHF) is a major thrust of Northeastern Tibet, bounding the Qilian Shan. It accommodates crustal shortening across this region and has produced a strong historical earthquake. Until now the slip rate has been poorly constrained, limiting our understanding of its role in the accommodation of deformation across this region. In this paper, faulted terraces at two sites on the western and middle segments of the FHF were mapped with satellite imagery and field observations. Chronological constraints are placed on the ages of displaced river terraces at these sites using terrestrial cosmogenic nuclide (TCN) exposure dating. These ages combined with offsets measured from SPOT 6 DEM's yield average vertical slip rates of 1.3 ± 0.1 mm/yr for the western segment since ∼207 ka and 0.9 ± 0.1 mm/yr since ∼46 ka for the middle segment. These data suggest that the FHF accommodates ∼15-20% of the total shortening across the Qilian Shan (5.5-7 mm/yr). In addition, comparisons of our data with published slip rates along the Northern Qilian Thrust Fault Zone show that the fastest tectonic uplift occurs along the western portion of the Northern Qilian Shan. This is consistent with estimates deduced from geomorphology. The western portion of the Qilian Shan is mainly controlled by compressional deformation produced by the northward movement of the Northeastern Tibetan Plateau, while the eastern Qilian Shan is mainly controlled by the eastward extrusion of material along the left-lateral Haiyuan strike-slip Fault.

Comparison of the results of different scale hydrogeological models on a terraced slope of Valtellina (Northern Italy)

Science.gov (United States)

Camera, C.; Apuani, T.; Masetti, M.; Mele, M.

2012-04-01

The aim of this work was to understand and reproduce the hydrological dynamics of a slope that is terraced by dry-stone retaining walls. At first, the processes of interest were analyzed with a classical 2D unsaturated-saturated finite elements analysis, reproducing the geometry of a single terrace. In a second moment, a raster analysis at the slope scale was performed. The studied slope is located in Valtellina (Northern Italy), near the village of Tresenda, and in the last 30 years it experienced several soil slip/debris flow events that in 1983 caused 18 victims. Direct observation of the events of 1983 permitted to recognize the principal triggering cause of these events in the formation of an overpressure at the base of a dry-stone wall, that caused its failure. Using field tests and monitoring activity as input and calibration data respectively, the 2D model is able to explain the mechanisms of rainfall infiltration that can lead to the formation and evolution of a perched groundwater table at the contact between the bedrock and the walls backfill soil. Once calibrated and validated the model has been used to investigate the influence of different parameters on the studied processes, such as walls height, bedrock slope angle, and changes of both isotropic and anisotropic saturated hydraulic conductivity of soil and wall. From this sensitivity analysis, one of the most interesting results is the ability of the model to well differentiate the behaviour of a well maintained wall with an higher hydraulic conductivity than soil, from a poorly maintained wall that has lost part of its drainage capacity. In fact, only in this latter circumstance significant pore-water pressures can form at the base of the retaining structure. Moving the problem to the slope scale, although the used raster-model takes into account both the unsaturated and saturated components of flux as the 2D model, it is less precise in the description of the processes involved in the formation of

Landslide Susceptibility Evaluation on agricultural terraces of DOURO VALLEY (PORTUGAL), using physically based mathematical models.

Science.gov (United States)

Faria, Ana; Bateira, Carlos; Laura, Soares; Fernandes, Joana; Gonçalves, José; Marques, Fernando

2016-04-01

The work focuses the evaluation of landslide susceptibility in Douro Region agricultural terraces, supported by dry stone walls and earth embankments, using two physically based models. The applied models, SHALSTAB (Montgomery et al.,1994; Dietrich et al., 1995) and SINMAP (PACK et al., 2005), combine an infinite slope stability model with a steady state hydrological model, and both use the following geophysical parameters: cohesion, friction angle, specific weight and soil thickness. The definition of the contributing areas is different in both models. The D∞ methodology used by SINMAP model suggests a great influence of the terraces morphology, providing a much more diffuse flow on the internal flow modelling. The MD8 used in SHALSTAB promotes an important degree of flow concentration, representing an internal flow based on preferential paths of the runoff as the areas more susceptible to saturation processes. The model validation is made through the contingency matrix method (Fawcett, 2006; Raia et al., 2014) and implies the confrontation with the inventory of past landslides. The True Positive Rate shows that SHALSTAB classifies 77% of the landslides on the high susceptibility areas, while SINMAP reaches 90%. The SINMAP has a False Positive Rate (represents the percentage of the slipped area that is classified as unstable but without landslides) of 83% and the SHALSTAB has 67%. The reliability (analyzes the areas that were correctly classified on the total area) of SHALSTAB is better (33% against 18% of SINMAP). Relative to Precision (refers to the ratio of the slipped area correctly classified over the whole area classified as unstable) SHALSTAB has better results (0.00298 against 0.00283 of SINMAP). It was elaborate the index TPR/FPR and better results obtained by SHALSTAB (1.14 against 1.09 of SINMAP). SHALSTAB shows a better performance in the definition of susceptibility most prone areas to instability processes. One of the reasons for the difference of

The Effect of Roof Angles on Indoor Air Temperatures in Terrace Houses in Malaysia

Directory of Open Access Journals (Sweden)

A. B. Ramly

2006-12-01

Full Text Available The main aim of energy efficiency in building design is to create buildings that utilise minimum amount of energy while meeting the comfort standards as high as or higher than those provided by conventional buildings.To achieve these standards, it is necessary to study the local environment in order to assess its positive and negative features (impact on the building. The results will provide a basic understanding of heat transfer and human thermal comfort requirements. It also provides foundation for which an energy efficient design of buildings can be established. The design of residential buildings has a significant impact on everyday lives of people. It includes the types and forms of buildings that are commonly occupied by people. In Malaysia, the 'terrace house' constitutes the majority of the residential building stock on which this study is based. The study considers the effects of the different roof angles on reducing solar gain and indoor temperatures through eight directions within 24 hours. To analyse and explain that effect, five different angles of roof were chosen for the simulations. In general, all the angles were chosen due 10 their architectural design characteristics. These angles start from 0 degree as a horizontal flat roof to 60 degrees, i.e. increment of every 15 degrees. The research is seen as providing a tool in evaluating the dynamic indoor air temperature and the effect of roof angles. The evaluation is derived from a series of computer simulations using commercially available software called BLAST.

Effects of terraces, surface steps and 'over-specular' reflection due to inelastic energy losses on angular scattering spectra for glancing incidence scattering

CERN Document Server

Danailov, D; O'Connor, D J

2002-01-01

Recent experiments and our molecular-dynamics simulations indicate that the main signal of the angular scattering spectra of glancing incidence scattering are not affected by the thermal motion of surface atoms and can be explained by our row-model with averaged cylindrical potentials. At the ICACS-18 Conference [Nucl. Instr. and Meth. B 164-165 (2000) 583] we reported good agreement between experimental and calculated multimodal azimuthal angular scattering spectra for the glancing scattering of 10 and 15 keV [Nucl. Instr. and Meth. B 180 (2001) 265, Appl. Surf. Sci. 171 (2001) 113] He sup 0 beam along the [1 0 0] direction on the Fe(1 0 0) face. Our simulations also predicted that in contrast to the 2D angular scattering distribution, the 1D azimuthal angular distribution of scattered particles is very sensitive to the interaction potential used. Here, we report more detailed calculations incorporating the influence of terraces and surface steps on surface channeling, which show a reduction of the angular s...

The radontechnical process of the sub-slab suction system in detached, semi-detached and terraced houses; Imupistejaerjestelmaen radontekninen toiminta eri tyyppisissae pien- ja rivitaloissa

Energy Technology Data Exchange (ETDEWEB)

Kettunen, A.V.; Rissanen, R.; Viljanen, M. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Structural Engineering and Building Physics; Arvela, H. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland)

1997-12-31

The sub-slab suction system is a repair method for decreasing radon transfer from soil to indoor air in houses. The sub-slab suction system changes the flow field with the aim to reduce the radon content under the ground slab or/and changes the flow direction from indoor air to foundation soil. The study is divided into the theoretical and experimental part. The theoretical part concentrates on solving the factors affecting the sub-slab suction system taking into consideration features of old houses. The experimental part uses the results of the theoretical part when the level and the type of the suction point had been chosen. The effect of the sub-slab suction system was tested with pressure difference experiments and the radon content measurements in 26 different, typical Finnish detached, semi-detached and terrace houses.

Dimensionamento de terraços de infiltração pelo método do balanço volumétrico Infiltration terrace design by volumetric balance method

Directory of Open Access Journals (Sweden)

Jarbas H. de Miranda

2004-12-01

Full Text Available As práticas de conservação de solo permitem o controle de perdas de solo e água em áreas agriculturáveis, objetivando assim a maximização do lucro sem provocar a redução da capacidade produtiva. Ante essa importância, há necessidade de se adotar procedimentos técnicos para o dimensionamento de estruturas conservacionistas. Assim, objetivou-se, com o presente trabalho, o desenvolvimento de um modelo computacional em linguagem Visual Basic 6.0, para dimensionamento de terraços em nível. O modelo foi aplicado para 3 localidades do Estado de São Paulo (Araçatuba, Piracicaba e Natividade da Serra. Pelos resultados obtidos, os valores da largura da seção parabólica de canais de terraço em nível de 0,5 m de profundidade para as 3 localidades, com período de retorno de 5 anos, foram de 3,30, 3,34 e 3,80 m, respectivamente.Soil conservation practices allow soil and water loss control in agricultural areas, aiming the maximization of profit without provoking reduction of yield potential. There is need to use technical procedures to design soil conservation structures. Therefore, the aim of the present work was the development of a computational model, in Visual Basic 6.0 language, for design of contour terrace. The model was applied for three municipalities of São Paulo State (Araçatuba, Piracicaba and Natividade da Serra. From the results obtained, it may be concluded that the width of a parabolic section contour terrace channel for these localities, with a return period of 5 years, was 3.30, 3.34 and 3.80 m, respectively, with 0,5 m of depth.

Geological characterization of agricultural terraces as a tool for the territorial safeguard and for the valorization of "Terroir"

Science.gov (United States)

Brancucci, Gerardo; Brancucci, Michele; Marescotti, Pietro; Poggi, Eugenio; Solimano, Monica; Vegnuti, Roberto; Giostrella, Paola; Tarolli, Paolo

2017-04-01

The progressive abandonment of the terraced areas of Liguria (NW Italy) is determining an inexorable land degradation, which causes, among other things, the erosive processes and the slope failure. Several studies highlighted the need of strategies for the recovery of abandoned agricultural lands by encouraging the productive reuse. Nevertheless, it is well known that agricultural activities in rural areas with steep slopes are strongly penalized by the high production costs determined by the adverse geomorphological conditions. For these reasons, one of the possible solutions is to encourage the production of high-quality agricultural crops, and to promote the uniqueness of the products. The uniqueness of the local products can be promoted not only by means of marketing strategy, mostly based on historical and traditional aspects of the productions, but also by correlating the product with the geological features (e.g., lithology, mineralogy and geochemistry) of the agricultural soils and parental rocks. These features are typically peculiar of a geographic area and thus strictly correlated with the site of production. This approach, together with the biological characterization of the crop, can link the cultivar to the geographical area of production thus evidencing peculiarities that are inimitable elsewhere. With this work we present the experimental results of investigations performed on several types of agricultural products (grapes and wines, olives and olive oils, apples) as well as on wild mushroom of the Boletus family. The analyses have been carried out either in laboratory and by means of field portable instruments (FP-EDXRF and FP-FTIR) which permitted a large number of in situ analyses, in a cost efficient and timely manner, thus allowing the realization of high spatial resolution compositional maps. This analytical approach also resulted particularly effective to improve the information obtained by traditional pedological and agronomical

Influence of permafrost on lake terraces of Lake Heihai (NE Tibetan Plateau)

Science.gov (United States)

Lockot, Gregori; Hartmann, Kai; Wünnemann, Bernd

2013-04-01

The Tibetan Plateau (TP) is one of the key regions for climatic global change. Besides the poles the TP is the third highest storage of frozen water in glaciers. Here global warming is three times higher than in the rest of the world. Additionally the TP provides water for billions of people and influences the moisture availability from the Indian and East Asian monsoon systems. During the Holocene extent and intensity of the monsoonal systems changed. Hence, in the last decades, a lot of work was done to reconstruct timing and frequency of monsoonal moisture, to understand the past and give a better forecast for the future. Comparative workings often show very heterogeneous patterns of timing and frequency of the Holocene precipitation and temperature maximum, emphasizing the local importance of catchment dynamics. In this study we present first results of lake Heihai (36°N, 93°15'E, 4500m a.s.l.), situated at the north-eastern border of the TP. The lake is surrounded by a broad band of near-shore lake sediments, attesting a larger lake extent in the past. These sediments were uplifted by permafrost, reaching nowadays heights ca. +8 meters above present lake level. Due to the uplift one of the main inflows was blocked and the whole hydrology of the catchment changed. To quantify the uplift of permafrost Hot Spot Analysis were accomplished at a DEM of the near-shore area. As a result regions of high permafrost uplift and those which mirror the original height of lake ground were revealed. The most obvious uplift took place in the northern and western part of the lake, where the four uplift centers are located. In contrast the southern and eastern areas show a rather degraded pattern (probably by fluvial erosion, thermokarst, etc.). The ancient lake bottom, without permafrost uplift was estimated to be 4-6 meters above the modern lake level. For a better understanding of permafrost interaction inside the terrace bodies a 5m sediment profile was sampled and

B. C. Hydro proposed 287 kV transmission line Kitimat to Terrace: Preliminary environmental assessment of fish and wildlife values

Energy Technology Data Exchange (ETDEWEB)

Hazelwood, W G

1991-01-01

The proposed two corridors for an additional 278 kV transmission line from Terrace to Kitimat, British Columbia were referenced for fisheries and wildlife sensitivity and impact. Route A parallels the existing powerline down the eastern edge of the Kitimat valley while Route B follows the western edge and is 12 km shorter. Fisheries values are paramount in the study area with populations of steelhead, pink, coho, chinook, chum and sockeye in both the Lakelse and Kitimat drainages. Recreational species are of strong secondary importance and support a viable tourist industry. Wildlife values are best represented by moose, bear, fur-bearers and waterfowl. Clearcut logging has depressed populations in the study area but regrowth of essential habitat and cover is allowing some species to increase in number. Trumpeter swans utilize the valley as a migration route while some remain as residents in warmer winters. The two proposed corridors were evaluated on a resource basis to determine the least impactive and sensitive route, with a general rating evolved with common criteria. The rating of Route B was significantly less sensitive than Route A, due to Route B being significantly shorter and drier. 2 figs.

Charred wood remains in the natufian sequence of el-Wad terrace (Israel): New insights into the climatic, environmental and cultural changes at the end of the Pleistocene

Science.gov (United States)

Caracuta, Valentina; Weinstein-Evron, Mina; Yeshurun, Reuven; Kaufman, Daniel; Tsatskin, Alexander; Boaretto, Elisabetta

2016-01-01

The major social and economic changes associated with the rise of a sedentary lifestyle and the gradual transition to food production in the southern Levant are often considered to have been triggered by climate changes at the end of the Pleistocene (∼20,000-11,000 years BP). This explanation, however, is biased by the scarcity of high-resolution climate records directly associated with human activity and the lack of refined palaeoecological studies from multi-stratified sites in the area. Here, we present the results of an anthracological analysis, carried out on charcoals collected along a continuous column of archaeological sediments in the Natufian site of el-Wad Terrace (Mount Carmel, Israel). We also present the carbon isotopes analysis of 14C-dated archaeological remains of Amygdalus sp. The analyses of charcoal shows the predominance of an oak forest including Quercus calliprinos and ithaburensis around the site during the Early Natufian building phase (∼14,600-13,700 cal BP), and the values of Δ13C point to a high rainfall rate. This period is followed by a marked decrease in the local rainfall between ∼13,700 and 12,000 cal BP). The reduction, culturally associated with the latest Early Natufian and the Late Natufian, is independently recorded by the speleothems of the region: Soreq Cave and Jerusalem Cave. This period incorporates an increase in drought tolerant species such as Amygdalus sp. Thermo-Mediterranean species, such as Olea europaea and Ceratonia siliqua, as well as Pistacia palaestina, which dominate the modern landscape, become established in the Holocene. We conclude that the Natufian settlement at el-Wad Terrace flourished in the context of oak forests, and subsequently occupation intensity decreased in concurrence to the drying trend. This shift does not correspond to the cultural typology (i.e. Early Natufian vs. Late Natufian). Human response to climate change at the terminal Pleistocene Levant was multifaceted and localized. Its

Agricultural terraces montoring and modeling: a field survey in Chianti region, Firenze, Italy – Second part

Science.gov (United States)

Preti, Federico; Caruso, Marco; Dani, Andrea; Cassiani, Giorgio; Romano, Nunzio; Tarolli, Paolo

2015-04-01

The two abstracts present the design and set-up of an experimental campaign which aims at sup-porting the modeling (conceptual and numerical) of water circulation in a terraced slope, and its in-fluence on stability of retaining dry stone walls. The case study is located at "Fattoria di Lamole" (Greve in Chianti, Firenze, Italy). At Lamole site both ancient and recently restored or rebuilt (with different techniques) dry stone walls are present. Furthermore the intense vineyards cultivation makes it very representative in terms of range of external stresses that affect both hillslopes and wall. The survey is developed within the bigger framework of landscape preservation as a way to prevent hydrogeological instabilities and landslide risks. Second Part A second effort is devoted to couple hydrological, hydraulic and geotechnical modeling: - Flow directions and the drainage area have been derived from DTM (high-resolution digital terrain model obtained by a terrestrial laser scanner.), and served for the RPII index calcula-tion (Tarolli et al., 2013), that is coherent with the critical spots observed in situ and marked with GPS. - Direct shear test on undisturbed and reconstituted soil samples will offer an estimation of the Mohr-Coulomb failure envelope parameters (friction angle and cohesion). - Retention curves related with different depths have been derived. - Geoelectric analysis in order to locate the bedrock and to determine the subterranean water flows originated from controlled infitration tests (1 l/s discharge). - A simple dry-wall stability model has been carried out; this model analyses the wall stability with finite elements method, evaluating pressures derived from uphill water infiltration, stone friction and buoyancy in retaining wall layers: simulated deformation are suitable with the observed ones. Acknowledgements Italian Research Project of Relevant Interest (PRIN2010-2011), prot. 20104ALME4, National network for monitoring, modeling, and

Landscape Change in Mediterranean Farmlands: Impacts of Land Abandonment on Cultivation Terraces in Portofino (Italy and Lesvos (Greece

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Sluis Theo Van Der

2014-01-01

Full Text Available The Mediterranean landscape has been rapidly changing over the past decades. Many regions saw a population decline, which resulted in changing land use, abandonment of marginal lands and colonisation by shrubs and tree species. Typical features like farming terraces, olive yards, and upland grasslands have been decreasing over the past 50 years. This results in a declining biodiversity and loss of traditional Mediterranean landscapes. In this paper we assess the landscape changes that took place in two areas, in Portofino, on the Italian Riviera, and Lesvos, a Greek island near the Turkish coast. We compared land use maps and aerial photographs over the past decades to quantify the land use changes in these two areas. Additional information was acquired from farmers’ interviews and literature. We found that changes are related to societal changes in the appraisal of agricultural land uses, and to the urban expansion, tourism and recreation. These diffuse processes are a result of policy measures and autonomous societal transformations. This is confirmed by the results of two interview surveys: between 1999 and 2012 agricultural land use in Portofino regional Park and buffer zone further marginalised, and the associated landscape changes are perceived as a substantial loss of character and identity. This problem is emblematic for large parts of the Mediterranean. Comparing different landscapes reveal similar processes of landscape change, which can be related to similar driving forces. Based on such comparisons, we learn about possible trajectories of change, and ask for a comprehensive approach to land use management.

Sea-level history during the Last Interglacial complex on San Nicolas Island, California: implications for glacial isostatic adjustment processes, paleozoogeography and tectonics

Science.gov (United States)

Muhs, Daniel R.; Simmons, Kathleen R.; Schumann, R. Randall; Groves, Lindsey T.; Mitrovica, Jerry X.; Laurel, Deanna

2012-01-01

San Nicolas Island, California has one of the best records of fossiliferous Quaternary marine terraces in North America, with at least fourteen terraces rising to an elevation of ~270 m above present-day sea level. In our studies of the lowest terraces, we identified platforms at 38-36 m (terrace 2a), 33-28 m (terrace 2b), and 13-8 m (terrace 1). Uranium-series dating of solitary corals from these terraces yields three clusters of ages: ~120 ka on terrace 2a (marine isotope stage [MIS] 5.5), ~120 and ~100 ka on terrace 2b (MIS 5.5 and 5.3), and ~80 ka (MIS 5.1) on terrace 1. We conclude that corals on terrace 2b that date to ~120 ka were reworked from a formerly broader terrace 2a during the ~100 ka sea stand. Fossil faunas differ on the three terraces. Isolated fragments of terrace 2a have a fauna similar to that of modern waters surrounding San Nicolas Island. A mix of extralimital southern and extralimital northern species is found on terrace 2b, and extralimital northern species are on terrace 1. On terrace 2b, with its mixed faunas, extralimital southern species, indicating warmer than present waters, are interpreted to be from the ~120 ka high sea stand, reworked from terrace 2a. The extralimital northern species on terrace 2b, indicating cooler than present waters, are interpreted to be from the ~100 ka sea stand. The abundant extralimital northern species on terrace 1 indicate cooler than present waters at ~80 ka. Using the highest elevations of the ~120 ka platform of terrace 2a, and assuming a paleo-sea level of +6 m based on previous studies, San Nicolas Island has experienced late Quaternary uplift rates of ~0.25-0.27 m/ka. These uplift rates, along with shoreline angle elevations and ages of terrace 2b (~100 ka) and terrace 1 (~80 ka) yield relative (local) paleo-sea level elevations of +2 to +6 m for the ~100 ka sea stand and -11 to -12 m for the ~80 ka sea stand. These estimates are significantly higher than those reported for the ~100 ka and ~80 ka

Work on the extension of Restaurant No. 1

CERN Multimedia

GS Department

2010-01-01

The work on the extension of Restaurant No. 1 will start on 12 April 2010. The section of the terrace currently available will be closed from this date onwards and the south terrace (see drawing) will gradually be made available in its place. Worksite for the extension of Restaurant No. 1.  Closure of current terrace on 2 April. Opening of south terrace on 12 April. Opening of second area of terrace at the end of April. Opening of third area of terrace in May.

ZONASI POTENSI PENCEMARAN AIR TANAH PADA TERAS SUNGAI CODE YOGYAKARTA (Zoning The Potential Groundwater Pollution at Code River Terrace, Yogyakarta

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Frista Yorhanita

2001-08-01

Full Text Available ABSTRAK Tujuan penelitian ini ialah untuk membuktikan bahwa biomassa Fusarium sp dapat mereduksi Cr(VI, dan biomassa Aspergillus niger dapat digunakan untuk mengambil ion krom dari larutan. Fusarium.sp ditumbuhkan pada media cair kentang dekftosa cair, ditambah K2Cr2O7 atau sludge limbah penyamakan kulit. Selanjutnya diamati perubahan warnanya, bila terjadi perubahan warna dan oranye ke ungu atau tak berwarna maka telah terjadi reduksi krom valensi VI menjadi krom valensi Ill. Aspergillus niger ditumbuhkan pada media Potato dectrose agar (PDA padat, dipindahkan ke media cair yang bensi bakto pepton, bakto dektrose dan srukronutrien. Produksi biomassa dilakukan pada labu erlenmeyer; setelah 5 hari dipanen dan dibuat bubuk. Bubuk ini digunakan untuk mengambil krom dari larutan. Hasil penelitian menunjukkan bahwa biomassa Fusarium sp dapat digunakan untuk mengambil krom dan larutan yang.mengandung KrCrrO, atau sludge limbah penyamakan kulit. Waktu inkubasi yang lebih lama meningkatkan absorbsi krom oleh biomassa Fascrium sp. Fusarium sp mampu mereduksi Cr(VI menjadi Cr(Iii. Biomassa Aspergillus niger dapat digunakan untuk mengambil krom dari larutan. Hasil terbaik diperoleh pada konsentrasi awal 100 mg/I, pada pH 2,0, berat biomassa 0,1 g, dan waktu kontak 12 jam, yaitu 96,23% untuk Cr(II| dan96,3 % untuk Cr(VI. Fusarium sp. dan A. niger dapat digunakan sebagai bioremediator dalam penanganan limbah penyamakan kulit secara biologi.   ABSTRACT The study area of this research was parts of the code river terraces, Yogyakarta. The aims of this research were as follows: (1 to determine the part of the code river terrace which has potential groundwater pollution; (2 to assess the natural physical factors (aquifer materials, depth of groundwater table, and the groundwater flow distance and the non-natural physical factors of environmental sanitation (houses density, population density, horizontal distance between pollution source and well, and the number

Two Late Pleistocene climate-driven incision/aggradation rhythms in the middle Dnieper River basin, west-central Russian Plain

DEFF Research Database (Denmark)

Panin, Andrei; Adamiec, Grzegorz; Buylaert, Jan-Pieter

2017-01-01

Pleistocene - Holocene climate cycle. The following events were detected. (1) Late MIS 5 - early MIS 4: aggradation of Terrace T1 following the deep incision at the end of MIS 6. (2) Late MIS 4 (40-30 ka): incision into Terrace T1 below the present-day river, formation of the main scarp in the bottom...... of the valley between Terrace T1 and Terrace T0/Floodplain levels. (3) MIS 2: aggradation of Terrace T0, lateral migrations of a shallow braided channel located few meters above the present-day river since ∼25 ka through the LGM. (4) 18-13 ka: incision into Terrace T0 below the modern river. Multiple...

ANALYSIS OF CLIMATIC AND SOCIAL PERFORMANCES OF LOW COST TERRACE HOUSING (LCTH: INTRODUCING THE AFFORDABLE QUALITY HOUSING (AQH CONCEPT IN MALAYSIA

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Noor Hanita Abdul Majid

2009-03-01

Full Text Available Low cost terrace housing (LCTH is the most common form and popular typology of public housing in Malaysia. The provision of the houses is deemed to be the most suitable to fulfil the needs to house low income families, and also as an alternative to high rise low cost housing. Since the implementation of these housing types, development on the layout and sizes of the house has taken place to provide for better living conditions. Literature review on the current LCTH suggested that there are deficiencies in fulfilling the requirements to provide quality and affordable housing for the low income families. This paper presents the scenario of the LCTH design based on secondary findings by researchers on housing in Malaysia. The secondary data provided the grounds for the proposal of affordable and quality housing (AQH to handle the problems that occurred at the LCTH. Both social and climatic considerations are included in the AQH, addressing issues on privacy, segregation of genders and community interaction; along with thermal comfort and natural ventilation. Decisions on the AQH are carefully extracted from a comparison analysis in the view to improve the current conditions. In order to verify some of the decisions on climatic design strategies, simulation results are presented. The results indicated that the design decisions have managed to improve on the natural ventilation conditions at the low cost houses. With reservations on the social conditions that are yet to be tested at the actual houses, the AQH has proven to be a step forward towards the provision of a better living environment.

Theoretical insights into the effect of terrace width and step edge coverage on CO adsorption and dissociation over stepped Ni surfaces.

Science.gov (United States)

Yang, Kuiwei; Zhang, Minhua; Yu, Yingzhe

2017-07-21

Vicinal surfaces of Ni are model catalysts of general interest and great importance in computational catalysis. Here we report a comprehensive study conducted with density functional theory on Ni[n(111) × (100)] (n = 2, 3 and 4) surfaces to explore the effect of terrace width and step edge coverage on CO adsorption and dissociation, a probe reaction relevant to many industrial processes. The coordination numbers (CN), the generalized coordination numbers and the d band partial density of states (d-PDOS) of Ni are identified as descriptors to faithfully reflect the difference of the step edge region for Ni[n(111) × (100)]. Based on analysis of the energy diagrams for CO activation and dissociation as well as the structural features of the Ni(311), Ni(211) and Ni(533) surfaces, Ni(211) (n = 3) is proposed as a model of adequate representativeness for Ni[n(111) × (100)] (n≥ 3) surface groups in investigating small molecule activation over such stepped structures. Further, a series of Ni(211) surfaces with the step edge coverage ranging from 1/4 to 1 monolayer (ML) were utilized to assess their effect on CO activation. The results show that CO adsorption is not sensitive to the step edge coverage, which could readily approach 1 ML under a CO-rich atmosphere. In contrast, CO dissociation manifests strong coverage dependence when the coverage exceeds 1/2 ML, indicating that significant adsorbate-adsorbate interactions emerge. These results are conducive to theoretical studies of metal-catalyzed surface processes where the defects play a vital role.

30 CFR 717.14 - Backfilling and grading of road cuts, mine entry area cuts, and other surface work areas.

Science.gov (United States)

2010-07-01

... control, or roads. (2) The vertical distance between terraces shall be as specified by the regulatory... as part of terraces. (4) Culverts and underground rock drains shall be used on the terrace only when...

Effects of soil and water conservation on crop productivity: Evidences from Anjenie watershed, Ethiopia

Science.gov (United States)

Adgo, Enyew; Teshome, Akalu

2014-05-01

Widespread soil and water conservation activities have been implemented in many parts of eastern Africa to control soil erosion by water and improve land productivity for the last few decades. Following the 1974 severe drought, soil and water conservation became more important to Ethiopia and the approach shifted to watershed based land management initiatives since the 1980s. To capture long-term impacts of these initiatives, a study was conducted in Anjenie Watershed of Ethiopia, assessing fanya juu terraces and grass strips constructed in a pilot project in 1984, and which are still functional nearly 30 years later. Data were collected from government records, field observations and questionnaire surveys administered to 60 farmers. Half of the respondents had terraced farms in the watershed former project area (with terrace technology) and the rest were outside the terraced area. The crops assessed were teff, barley and maize. Cost-benefit analyses were used to determine the economic benefits with and without terraces, including gross and net profit values, returns on labour, water productivity and impacts on poverty. The results indicated that soil and water conservation had improved crop productivity. The average yield on terraced fields was 0.95 t ha-1 for teff (control 0.49), 1.86 t ha-1 for barley (control 0.61), and 1.73 t ha-1 for maize (control 0.77). The net benefit was significantly higher on terraced fields, recording US 20.9 (US -112 control) for teff, US 185 (US -41 control) for barley and US -34.5 (US - 101 control) ha-1 yr-1 for maize. The returns on family labour were 2.33 for barley, 1.01 for teff, and 0.739 US per person-day for maize grown on terraced plots, compared to US 0.44, 0.27 and 0.16 per person-day for plots without terraces, respectively. Using a discount rate of 10%, the average net present value (NPV) of barley production with terrace was found to be about US 1542 over a period of 50 years. In addition, the average financial

Post-fire suspended sediment dynamics in a Mediterranean terraced catchment using a nested approach

Science.gov (United States)

Garcia-Comendador, Julián; Fortesa, Josep; Calsamiglia, Aleix; Calvo-Cases, Adolfo; Estrany, Joan

2017-04-01

Wildfires promote serious disturbances in the hydrological and sediment dynamics at catchment scale modifying the runoff generation response and the sediment delivery. The hysteretic loops analyses can help to clarify some landscape changes induced by fire. Accordingly, these spatio-temporal relationships between discharge and sediment transport at event scale enable the location of sediment sources, the availability or depletion of sediment and the precipitation threshold necessary to generate functional hillslope-channel connectivity. In addition, a nested catchment approach allows the characterization of the hydro-sedimentological dynamics in different landscape compartments, observing the incidence of the changes generated in the landscape and its evolution to control soil erosion and to implement useful mitigation practices after fire. In July 2013 a large wildfire (2,450 ha) severely affected the western part of Mallorca (Balearic Islands, Spain). The hydrological and sediment delivery processes were assessed in the first three post-fire hydrological years in a representative catchment when the window of disturbance is typically more open. A nested approach was applied in which two gauging stations (i.e., US 1.2 km2 and DS 4.8 km2) were established in September 2013 with continuous measurement of rainfall, water and sediment yield. At DS, a minimal runoff (i.e., 11 mm with 2% of coefficient) and low sediment yield (i.e., 6.3 t km2 yr-1) were generated on average in the study period in which rainfall averaged amount (i.e., 468 mm ± 141) and intensities were representative of long-term records. The hysteretic analysis allowed a better understanding of the effects of wildfires and terraces in sediment yields. For the whole study period, the percentage distribution was 43% (US; two monitored years) and 40% (DS; three monitored years) for clockwise loops in front of 57% (US) and 60% (DS) for counter clockwise loops. This percentage of counter clockwise loops was

Consequences of Common Topological Rearrangements for Partition Trees in Phylogenomic Inference.

Science.gov (United States)

Chernomor, Olga; Minh, Bui Quang; von Haeseler, Arndt

2015-12-01

In phylogenomic analysis the collection of trees with identical score (maximum likelihood or parsimony score) may hamper tree search algorithms. Such collections are coined phylogenetic terraces. For sparse supermatrices with a lot of missing data, the number of terraces and the number of trees on the terraces can be very large. If terraces are not taken into account, a lot of computation time might be unnecessarily spent to evaluate many trees that in fact have identical score. To save computation time during the tree search, it is worthwhile to quickly identify such cases. The score of a species tree is the sum of scores for all the so-called induced partition trees. Therefore, if the topological rearrangement applied to a species tree does not change the induced partition trees, the score of these partition trees is unchanged. Here, we provide the conditions under which the three most widely used topological rearrangements (nearest neighbor interchange, subtree pruning and regrafting, and tree bisection and reconnection) change the topologies of induced partition trees. During the tree search, these conditions allow us to quickly identify whether we can save computation time on the evaluation of newly encountered trees. We also introduce the concept of partial terraces and demonstrate that they occur more frequently than the original "full" terrace. Hence, partial terrace is the more important factor of timesaving compared to full terrace. Therefore, taking into account the above conditions and the partial terrace concept will help to speed up the tree search in phylogenomic inference.

Processes and Causes of Accelerated Soil Erosion on Cultivated ...

African Journals Online (AJOL)

Processes and Causes of Accelerated Soil Erosion on Cultivated Fields of South Welo, Ethiopia. ... In most of the highlands, crop cultivation is carried out without any type of terracing, while about 74 per cent of this land requires application of contour plowing, broad-based terracing, or bench terracing. The third group of ...

Quantification of surface uplift by using paleo beach deposits (Oman, Northern Indian Ocean)

Science.gov (United States)

Hoffmann, Gösta; Schneider, Bastian; Monschau, Martin; Mechernich, Silke

2017-04-01

The study focusses on a coastal area along the Arabian Sea in Oman. Here, a staircase of marine terraces is seen as geomorphological evidence suggesting sub-recent uplift of a crustal block in the northeast of the Arabian Peninsula. The erosional terraces are cut into Paleocene to Early Eocene limestone formations. These limestone formations are underlain by allochtonous ophiolites. We mapped the terraces over a distance of 60 km and identified at least 8 terrace levels in elevations up to 350 m above present sea level. The uppermost terraces are erosional, whereas the lower ones are depositional in style. Mollusc and coral remains as well as beach-rock are encountered on the terrace surfaces. The formations are dissected by NW-SE trending faults. Some of the terraces are very pronounced features in the landscape and easy to trace, others are partly eroded and preserved as remnants only. The deposit along the shoreline angle act as a datum making use of the fact that the rocks formed in a defined horizontal level which is the paleo-sea level. Hence, any offset from the primary depositional level is evidence for neotectonic movements. We utilise differential GPS to map the elevation of beachrock deposits. Age constraints on terrace formation is derived by sampling the beachrock deposits and dating using cosmogenic nuclii. The results indicate ongoing uplift in the range of less than a millimetre per year. The uplift is differential as the terraces are tilted. We mapped oblique normal and strike-slip faults in the younger terraces. We hypothesise that the mechanism responsible for the uplift is not tectonics but driven by the serpentinisation of the ophiolite that underlie the limestone formations. One process during the serpentinisation is the hydration of the mantle rocks which is responsible for a decrease in density. The resulting buoyancy and significant solid volume increase lead to the observed deformation including uplift.

Directory of Open Access Journals (Sweden)

Rehmat Ullah, Shahid Mahmood Mian,

2012-05-01

Full Text Available Soil biological health is one of the best indicators for soil fertility thus plays a significant role in sustainability of cropping systems. This study was designed to investigate the impact of different seasonal variations and cropping systems on soil microbial biomass and enzymatic activities in sloppy arid soils. Soil samples were collected from the sloppy soils (high, medium and low height terraces of Khairimurat areas under wheat (Triticum aestivum–millet (Pennisetum glaucum and wheat (Triticum aestivum–mung bean (Vigna radiate cropping systems. The results revealed that the soil microbial biomass Carbon (Cmic, Nitrogen (Nmic, Phosphorous (Pmic, soil enzymes such as Dehydrogenase (DH and Alkaline Phosphatase (AP activity entirely depends on the soil water availability under both cropping systems at all height terraces. The wheat-mung bean cropping systems stored relatively more Nmic, Pmic, AP (activity and less Cmic, DH (activity as compared to wheat-millet cropping systems. Regarding the slope gradient under both cropping patterns, high height terraces had retained more Cmic contents, medium height terraces had shown more DH activity and low height terraces had maintained more Pmic contents. In addition to this, Nmic contents and AP activity remained almost similar in all types of terraces under both cropping patterns. Pertaining to seasonal variations under both cropping patterns, the summer season had shown more Cmic, Nmic, Pmic, DH and AP activity as compared to spring, winter and autumn season in all types of terraces. The soil water contents increased down to depth in all types of terraces under both cropping patterns. However, soil water contents remained heterogeneous in all types of terraces under both cropping patterns. In conclusion, it is suggested that in arid environments, cover crops be included in cropping system in order to enhance soil biological health.

Electrochemical characterization of irreversibly adsorbed germanium on platinum stepped surfaces vicinal to Pt(1 0 0)

International Nuclear Information System (INIS)

Rodriguez, P.; Herrero, E.; Solla-Gullon, J.; Vidal-Iglesias, F.J.; Aldaz, A.; Feliu, J.M.

2005-01-01

The electrochemical behavior of germanium irreversibly adsorbed at stepped surfaces vicinal to the Pt(1 0 0) pole is reported. The process taking part on the (1 0 0) terraces is evaluated from charge density measurements and calibration lines versus the terrace dimension are plotted. On the series Pt(2n - 1,1,1) having (1 1 1) monoatomic steps, the charge involved in the redox process undergone by the irreversibly adsorbed germanium is able to account for (n - 0.5) terrace atoms, thus suggesting some steric difficulties in the growth of the adlayer on the (1 0 0) terraces. Conversely, no steric problems are apparent in the series Pt(n,1,0) in which more open (1 0 0) steps are present on the (1 0 0) terraces. In this latter case the charge density under the germanium redox peaks is proportional to the number of terrace atoms. Some comparison is made with other stepped surfaces to understand the behavior and stability of germanium irreversibly adsorbed on the different platinum surface sites

Evaluation of nekton use and habitat characteristics of restored Louisiana marsh

Science.gov (United States)

Thom, C.S.B.; Peyre, M.K.G.L.; Nyman, J.A.

2004-01-01

Marsh terracing and coconut fiber mats are two wetland restoration techniques implemented at Sabine National Wildlife Refuge, Louisiana, USA. Using nekton as an indicator of habitat quality, nekton community assemblages were compared between terraced, coconut-matted, unmanaged marsh (restoration goal), and open water (pre-restoration) habitats. Using a throw trap and a 3 m ?? 2 m straight seine, 192 nekton samples were collected over four dates in 2001 and 2002 at all habitats. Nekton abundance was similar at unmanaged marsh (restoration goal), coconut mat, and terrace edge, and significantly higher than at open water (pre-restoration) sites (P Coconut-matted habitat and unmanaged marsh edges had significantly higher numbers of benthic dependent species than terrace edges (P coconut-matted sites. Future restoration projects may evaluate the combined use of coconut mats with terracing projects in order to enhance habitat for benthic dependent nekton.

The impact of informal irrigation practices on soil drainage condition, soil pollution and land suitability for agriculture in El Saf area of El Giza Governorate

Directory of Open Access Journals (Sweden)

Hanan E.M. El Azab

2015-12-01

Full Text Available The study area was selected in El Saf District of El Giza Governorate in Egypt, covering 21461.4 ha of Nile sediments and their outskirts of alluvial higher and lower terraces. The aim of this study was to assess the impact of informal irrigation practices on drainage deterioration, soil pollution and land suitability for agricultural use using the satellite LDCM data 2013. From the lower alluvial terraces (partly cultivated using wastewater, the drainage flows westward via descending slopes resulting in land deterioration in both the alluvial lower terraces and alluvial plain of River Nile. The drainage conditions are excessively drained soils in the alluvial upper terraces within soils of Typic Haplocalcids, sandy skeletal, but in the lower terraces it partly occurred within soils of Typic Torriorthents, sandy skeletal. Moderately well drained soils occurred in soils of Typic Torriorthents, sandy in the alluvial lower terraces, while in the alluvial plain of Nile sediments are Sodic Haplotorrerts, fine. Poorly drained soils in the lower alluvial terraces have soils of Typic Epiaquents, sandy associated with Sodic Psammaquents and Aquic Haplocalcids, coarse loamy, while in the alluvial plain of River Nile the soils are Halic Epiaquerts, fine. Very poorly drained soils (submerged areas are scattered spots in both the lower alluvial terraces and the alluvial plain. In the alluvial plain of River Nile, 1967.1 ha become not suitable for the traditional cultivated crops, while in the alluvial terraces 3251.0 ha are not suitable for the proposed cultivation of Jojoba plants. Heavy metals of Cadmium (Cd, Cobalt (Co, Lead (Pb and Nickel (Ni were added to the soil surface and sub-surface in the irrigated areas by wastewater in the lower alluvial terraces (moderately well drained soils, but Cd and Co exceeded the standards of permissible total concentrations in these soils. The same metals were added to soil sub-surface layers in the alluvial plain

Morphosedimentary and hydrographic features of the northern Argentine margin: The interplay between erosive, depositional and gravitational processes and its conceptual implications

Science.gov (United States)

Preu, Benedict; Hernández-Molina, F. Javier; Violante, Roberto; Piola, Alberto R.; Paterlini, C. Marcelo; Schwenk, Tilmann; Voigt, Ines; Krastel, Sebastian; Spiess, Volkhard

2013-05-01

Bottom currents and their margin-shaping character became a central aspect in the research field of sediment dynamics and paleoceanography during the last decades due to their potential to form large contourite depositional systems (CDS), consisting of both erosive and depositional features. A major CDS at the northern Argentine continental margin was studied off the Rio de la Plata River by means of seismo- and hydro-acoustic methods including conventional and high-resolution seismic, parametric echosounder and single and swath bathymetry. Additionally, hydrographic data were considered allowing jointly interpretation of morphosedimentary features and the oceanographic framework, which is dominated by the presence of the dynamic and highly variable Brazil-Malvinas Confluence. We focus on three regional contouritic terraces identified on the slope in the vicinity of the Mar del Plata Canyon. The shallowest one, the La Plata Terrace (˜500 m), is located at the Brazil Current/Antarctic Intermediate Water interface characterized by its deep and distinct thermocline. In ˜1200 m water depth the Ewing Terrace correlates with the Antarctic Intermediate Water/Upper Circumpolar Deep Water interface. At the foot of the slope in ˜3500 m the Necochea Terrace marks the transition between Lower Circumpolar Deep Water and Antarctic Bottom Water during glacial times. Based on these correlations, a comprehensive conceptual model is proposed, in which the onset and evolution of contourite terraces is controlled by short- and long-term variations of water mass interfaces. We suggest that the terrace genesis is strongly connected to the turbulent current pattern typical for water mass interfaces. Furthermore, the erosive processes necessary for terrace formation are probably enhanced due to internal waves, which are generated along strong density gradients typical for water mass interfaces. The terraces widen through time due to locally focused, partly helical currents along the

Geomorphic and sedimentary responses of the Bull Creek Valley (Southern High Plains, USA) to Pleistocene and Holocene environmental change

Science.gov (United States)

Arauza, Hanna M.; Simms, Alexander R.; Bement, Leland C.; Carter, Brian J.; Conley, Travis; Woldergauy, Ammanuel; Johnson, William C.; Jaiswal, Priyank

2016-01-01

Fluvial geomorphology and stratigraphy often reflect past environmental and climate conditions. This study examines the response of Bull Creek, a small ephemeral creek in the Oklahoma panhandle, to environmental conditions through the late Pleistocene and Holocene. Fluvial terraces were mapped and their stratigraphy and sedimentology documented throughout the course of the main valley. Based on their elevations, terraces were broadly grouped into a late-Pleistocene fill terrace (T3) and two Holocene fill-cut terrace sets (T2 and T1). Terrace systems are marked by similar stratigraphies recording the general environmental conditions of the time. Sedimentary sequences preserved in terrace fills record the transition from a perennial fluvial system during the late glacial period and the Younger Dryas to a semiarid environment dominated by loess accumulation and punctuated by flood events during the middle to late Holocene. The highest rates of aeolian accumulation within the valley occurred during the early to middle Holocene. Our data provide significant new information regarding the late-Pleistocene and Holocene environmental history for this region, located between the well-studied Southern and Central High Plains of North America.

The Effect of Community-Based Soil and Water Conservation Practices on Abundance and Diversity of Soil Macroinvertebrates in the Northern Highlands of Ethiopia

Directory of Open Access Journals (Sweden)

Mengistu Welemariam

2018-04-01

Full Text Available Soil and water conservation (SWC practices in the northern highlands of Ethiopia have important implications for land restoration and biodiversity recovery. The present study determined soil macroinvertebrate (SMI abundance and diversity in response to spatial conditions i.e., generated by different conservation practices, soil depth, and temporal seasonality with the wet and dry season. The SWC practices considered were exclosure + terrace, exclosure alone, terraces, and non-conserved grazing lands. Each SWC measure was selected in three sites that were considered as replications due to low heterogeneity in terms of human and livestock disturbances and biophysical factors. Soil macroinvertebrates were collected using a monolith according to tropical soil biology and fertility (TSBF method. The highest density (55% of SMI was found in exclosures followed by terraces 26%. Non-conserved communal grazing lands account for only 19% of the total. Shannon diversity index was significantly (P < 0.05 higher (1.21 in the exclosures supported with terraces and the lowest (0.9 was observed in the non-conserved communal grazing lands. Diversity was also significantly (P < 0.05 higher (1.26 in wet than dry season (0.70. The highest (41% Sorensen similarity index among SMI was found between exclosures with terraces and exclosures alone during the wet season. The lowest (20% Sorensen similarity index was found between terraces alone and exclosures with terraces in dry season. Soil macroinvertebrate abundance was higher in upper (0–10 cm than lower (10–20 and 20–30 cm soil depth. Soil macroinvertebrate abundance was positively and strongly correlated with soil moisture (R2 = 0.85 and soil organic carbon stock (R2 = 0.95. However, it was negatively (R2 = −0.71 correlated with bulk density. Generally, the abundance and diversity of SMI increased as exclosures and communal grazing lands are supported with terraces.

Soil characterization using patterns of magnetic susceptibility versus effective radium concentration

Directory of Open Access Journals (Sweden)

F. Girault

2011-08-01

Full Text Available Low-field magnetic susceptibility χ_m and effective radium concentration EC_Ra, obtained from radon emanation, have been measured in the laboratory with 129 soil samples from Nepal. Samples along horizontal profiles in slope debris or terrace scarps showed rather homogeneous values of both χ_m and EC_Ra. One sample set, collected vertically on a lateritic terrace scarp, had homogeneous values of EC_Ra while χ_m increased by a factor of 1 to 10 for residual soils and topsoils. However, for a set of samples collected on three imbricated river terraces, values of EC_Ra, homogeneous over a given terrace, displayed a gradual increase from younger to older terraces. By contrast, χ_m showed more homogeneous mean values over the three terraces, with a larger dispersion, however, for the younger one. Similarly, Kathmandu sediments exhibited a large increase in EC_Ra from sand to clay layers, while χ_m increased moderately. The combination of χ_m and EC_Ra, thus, provides a novel tool to characterize quantitatively various soil groups and may be of interest to distinguish modes of alteration or deposition histories.

Sabine National Wildlife Refuge 1999

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Terracing uses existing bottom sediments to form terraces or ridges at marsh elevation and the intertidal zone is planted with marsh vegetation. This study examined...

30 CFR 715.14 - Backfilling and grading.

Science.gov (United States)

2010-07-01

... implement the postmining land use plan. (ii) The vertical distance between terraces shall be as specified by... case may highwalls be left as part of terraces. (iv) Culverts and underground rock drains shall be used...

Excavation of Site U14/1945, Oropi Valley, Tauranga

International Nuclear Information System (INIS)

Campbell, M.

2004-01-01

Site U14/1945 was originally recorded as two small terraces, with two probable kumara storage pits visible on the surface of the upper terrace, and shell midden visible on the surface of the lower terrace, on a low, approximately 4 m high, hill. The most unusual feature in the site, and my main purpose in writing this paper, was the oven scoop in Trench 1. This feature appeared rather unusual when excavated for a number of reasons. 6 refs., 6 figs., 1 tab

Evaluation of soil carbon pools after the addition of prunings in subtropical orchards placed in terraces

Science.gov (United States)

Márquez San Emeterio, Layla; Martín Reyes, Marino Pedro; Ortiz Bernad, Irene; Fernández Ondoño, Emilia; Sierra Aragón, Manuel

2017-04-01

The amount of carbon that can be stored in a soil depends on many factors, such as the type of soil, the chemical composition of plant rests and the climate, and is also highly affected by land use and soil management. Agricultural ecosystems are proved to absorb a large amount of CO2 from the atmosphere through several sustainable management practices. In addition, organic materials such as leaves, grass, prunings, etc., comprise a significant type of agricultural practices as a result of waste recycling. The aim of this research was to evaluate the effects of the addition of different organic prunings on the potential for carbon sequestration in agricultural soils placed in terraces. Three subtropical orchards were sampled in Almuñécar (Granada, S Spain): mango (Mangifera indica L.), avocado (Persea americana Mill.) and cherimoya (Annonacherimola Mill.). The predominant climate is Subtropical Mediterranean and the soil is an Eutric Anthrosol. The experimental design consisted in the application of prunings from avocado, cherimoya and mango trees, placed on the surface soil underneath their correspondent trees, as well as garden prunings from the green areas surrounding the town center on the surface soils under the three orchard trees. Control experiences without the addition of prunings were also evaluated. These experiences were followed for three years. Soil samples were taken at4 cm depth. They were dried for 3-4 days and then sieved (<2 mm).Total soil organic C, water-soluble soil organic C, mineral-associated organic C and non-oxidable C were analyzed and expressed as carbon pools (Mg C ha-1for total soil organic C, or Kg C ha-1for the others). The results showed an increase of all organic carbon pools in all pruning treatments compared to the control experiences. Differences in total organic carbon pool were statistically significant between soils under avocado prunings and their control soil, and between soils under garden prunings with cherimoya and

Depositional facies and aqueous-solid geochemistry of travertine-depositing hot springs (Angel Terrace, Mammoth Hot Springs, Yellowstone National Park, USA)

Energy Technology Data Exchange (ETDEWEB)

Fouke, B.W.; Farmer, J.D.; Des Marais, D.J.; Pratt, L.; Sturchio, N.C.; Burns, P.C.; Discipulo, M.K.

2000-05-01

Petrographic and geochemical analyses of travertine-depositing hot springs at Angel Terrace, Mammoth Hot Springs, Yellowstone National Park, have been used to define five depositional facies along the spring drainage system. Spring waters are expelled in the vent facies at 71 to 73 C and precipitate mounded travertine composed of aragonite needle botryoids. The apron and channel facies (43--72 C) is floored by hollow tubes composed of aragonite needle botryoids that encrust sulfide-oxidizing Aquificales bacteria. The travertine of the pond facies (30--62 C) varies in composition from aragonite needle shrubs formed at higher temperatures to ridged networks of calcite and aragonite at lower temperatures. Calcite ice sheets, calcified bubbles, and aggregates of aragonite needles (fuzzy dumbbells) precipitate at the air-water interface and settle to pond floors. The proximal-slope facies (28--54 C), which forms the margins of terracette pools, is composed of arcuate aragonite needle shrubs that create small microterracettes on the steep slope face. Finally, the distal-slope facies (28--30 C) is composed of calcite spherules and calcite feather crystals. Despite the presence of abundant microbial mat communities and their observed role in providing substrates for mineralization, the compositions of spring-water and travertine predominantly reflect abiotic physical and chemical processes. Vigorous CO{sub 2} degassing causes a +2 unit increase in spring water pH, as well as Rayleigh-type covariations between the concentration of dissolved inorganic carbon and corresponding {delta}{sup 13}C. Travertine {delta}{sup 13}C and {delta}{sup 18}O are nearly equivalent to aragonite and calcite equilibrium values calculated from spring water in the higher-temperature ({approximately}50--73 C) depositional facies. Conversely, travertine precipitating in the lower-temperature (<{approximately}50 C) depositional facies exhibits {delta}{sup 13}C and {delta}{sup 18}O values that are as

Strike slip faulting inferred from offsetting of drainages: Lower ...

Indian Academy of Sciences (India)

Two levels of fluvial terraces have developed along the ... (a) Two levels of alluvial terraces abutting against the .... source mechanics; (eds) Das J, Boatwright J, Scholz C H, ... tectonics and alluvial rivers; Cambridge University Press. NY, 276 ...

An experimental study of furan adsorption and decomposition on vicinal palladium surfaces using scanning tunneling microscopy

Science.gov (United States)

Loui, A.; Chiang, S.

2018-04-01

The intact adsorption and decomposition of furan (C4H4O) on vicinal palladium surfaces with (111)-oriented terraces has been studied by scanning tunneling microscopy (STM) over a range of temperatures. STM images at 225 K show that furan molecules lie flat and prefer to adsorb at upper step edges. At 225 K, furan molecules adsorbed on "narrow" terraces of 20 to 45 Å in width appear to diffuse more readily than those adsorbed on "wide" terraces of 160 to 220 Å. A distinct population of smaller features appears in STM images on "narrow" terraces at 288 K and on "wide" terraces at 415 K and is identified with the C3H3 decomposition product, agreeing with prior studies which demonstrated that furan dissociates on Pd(111) to yield carbon monoxide (CO) and a C3H3 moiety in the 280 to 320 K range. Based on our direct visualization of this reaction using STM, we propose a spatial mechanism in which adsorption of furan at upper step edges allows catalysis of the dissociation, followed by diffusion of the product to lower step edges.

Quaternary geologic map of the north-central part of the Salinas River Valley and Arroyo Seco, Monterey County, California

Science.gov (United States)

Taylor, Emily M.; Sweetkind, Donald S.

2014-01-01

Arroyo Seco, a perennial drainage in the central Coast Range of California, records a sequence of strath terraces. These terraces preserve an erosional and depositional history, controlled by both climate change and regional tectonics. These deposits have been mapped and correlated on the basis of field investigations, digital terrain analysis, stream gradient profiles, evaluation of published regional soil maps, and satellite imagery. Seven of the strath terraces and associated alluvial fans have been dated by optically stimulated luminescence (OSL) or infrared stimulated luminescence (IRSL). The OSL and IRSL dates on seven of the strath terraces and associated alluvial fans in Arroyo Seco are approximately >120 ka, >65 ka, 51–46 ka, 36–35 ka, 9 ka, and 2–1 ka. These dates generally fall within the range of ages reported from many well-dated marine terraces on the California coast that are formed during sea-level high stands. Tectonic movements, consistently upward, result in a constantly and slowly emerging coastline, however, the regional effects of climate change and resulting eustatic sea-level rises are interpreted as the driving mechanism for erosion and aggradation in Arroyo Seco.

Anisotropic superconducting properties and fabrication of submicrometre bridges in misaligned Bi-Sr-Ca-Cu-O (2212) films

CERN Document Server

Moriya, M; Usami, K; Goto, T; Kobayashi, T

2002-01-01

In this paper, we report on misaligned Bi-Sr-Ca-Cu-O (2212) films that have been deposited on vicinal strontium titanate substrates using a dc sputtering system. We measured the temperature dependences of resistivity across and along the terrace, and only the resistivity across the terrace slightly decreased with the increase of the temperature in the normal state region. The estimated anisotropy parameter gamma was smaller than that of single crystal, but a significant anisotropy was observed. Submicrometre bridges were fabricated, and the temperature dependence of the critical current density was investigated. The value of the critical current density across the terrace is smaller than the value of that along the terrace. This suggests that the current partially flows along the c-axis. However, a multi-branch structure was not observed even after post annealing in oxygen atmosphere at low pressure.

The effect of pre-Hispanic agriculture practices on soils in the Western Cordillera of the Peruvian Andes (region Laramate, 14.5°S)

Science.gov (United States)

Leceta, Fernando; Mächtle, Bertil; Schukraft, Gerd; Eitel, Bernhard

2013-04-01

An integrated geoarchaeological study focuses on a group of three archaeological sites. This study comprises soils on pre-Columbian artificial terraces against their nondisturbed pedological context. Six terraces and three soils lacking of archaeological evidence and actual use, are examined to identify morphological and geochemical features generated by the sustained agrarian use. Aim is to understand the land-use and pedological history of the Laramate region, as an agricultural center in pre-Columbian times. Preliminary results show recurrent sequences within the terraces, characterized by two edaphic cycles; a poorly developed Ap modern topsoil is underlaid by one well-preserved 2Ah paleosol. Analytical data shows prehispanic terraces as a sustained agricultural system. Marked by its use and position, higher availability of nutrients and deeper soils, are found at agricultural terraces, located over a debris cone. Significant charcoal fragments for radiocarbon dating at Ayllapampa and Sihulca archeological sites, with a minimum age for terrace construction of Cal 1 sigma AD 675-766 and 782-893 respectively; it remains unclear if another stage of construction. There is no evidence that the terraces have alternated between periods of cultural decline and boom. Rather, reconstructions or modifications to the original structure and the absence of paleosols, address to a continuous use until its abandonment. Today, they produce only under fallow-system. There are no archeological signs of massive irrigation systems (Reindel 2011, pers. comm.). Its installation could only be linked to more favorable climatic conditions, like those described for The Early Horizon (800-200 BC), The Early Intermediate Period (200 BC-600 AD), and The Late Intermediate (Period 1000-1438 AD) (Eitel et al. 2005, Mächtle 2007). As reported on other archeological sites in southern Peru (Branch et al. 2007), an extensive terrace agricultural system during the Middle Horizon (500-1000 AD

MULTI-FOLD, SEISMIC-STYLE TDEM INDUCTION OFFSET PROFILING AT KENTLAND FARMS, VA

Science.gov (United States)

Kazlauskas, E. M.; Weiss, C. J.

2009-12-01

An outstanding question in Valley and Ridge geology is the geomorphological history and hydrologic framework of the New River terraces. And while depth to bedrock on the upper terraces remains unknown, knowledge of the bedrock interface is key to addressing two specific issues: What is the geometry and connectivity of karst features such as sinkholes and what is the structure and depositional history of these terraces? To answer these questions, Kentland Farms (located in the Valley and Ridge of Southwest Virginia) has been chosen as the study site for its exceptional development of terrace deposits, nearly unrestricted access to its grounds, sparse vegetation coverage, and numerous sinkholes with a clear topographic expression. The Kentland Farms study area is characterized by heavily weathered, fluvial terrace deposits ranging from a few meters thickness to an estimated 70 m, overlying a karstic, Cambrian aged Elbrook Formation limestone. The terrace deposits consist of weathered clay units of varying composition with interbedded cobble and gravel horizons. The nature of the underlying bedrock coupled with the complex structure of the terrace deposits present difficulties in location of the bedrock interface. Due to complicated geology, a novel, multi-fold, seismic-style, Time Domain Electromagnetic (TDEM) induction survey was conducted in order to provide a more robust data set than a traditional common offset survey as well as to increase lateral resolution. This approach consists of taking multiple transmitter “shots” at a fixed position with a spread of receiver locations at fixed offset intervals (10m in this survey). The procedure is then repeated by moving the transmitter one interval at a time until the line is complete. 1-D inversions generated by using different transmitter-receiver offsets were analyzed to create a set of laterally constrained vertical profiles. In addition, multi-fold, seismic-style TDEM induction offset profiling allowed for

A refined model of Quaternary valley downcutting emphasizing the interplay between tectonically triggered regressive erosion and climatic cyclicity

Science.gov (United States)

Demoulin, A.; Beckers, A.; Rixhon, G.; Braucher, R.; Bourlès, D.; Siame, L.

2012-04-01

While climatic models of valley downcutting discuss the origin of terrace staircases in valleys of middle Europe within the frame of alternating cold and temperate periods of the Quaternary, other models, starting from a base level fall imposed by an initial tectonic signal, describe the response of the drainage network mainly as the propagation of an erosion wave from the place of base level fall (the margin of the uplifted region) toward the headwaters, the two types of model being rarely confronted. In the Ardennes (West Europe), cosmogenic 10Be and 26Al ages have recently been calculated for the abandonment of the Younger Main Terrace (YMT) level (Rixhon et al., 2011), a prominent feature at mid-height of the valleysides marking the starting point of the mid-Pleistocene phase of deep river incision in the massif. These ages show that the terrace has been abandoned diachronically as the result of a migrating erosion wave that started at 0.73 Ma in the Meuse catchment just north of the massif, soon entered the latter, and is still visible in the current long profiles of the Ardennian Ourthe tributaries as knickpoints disturbing their upper reaches. At first glance, these new findings are incompatible with the common belief that the terraces of the Ardennian rivers were generated by a climatically triggered stepwise general incision of the river profiles. However, several details of the terrace staircases (larger than average vertical spacing between the YMT and the next younger terrace, varying number of post-YMT terraces in trunk stream, tributaries and subtributaries) show that a combination of the climatic and tectonic models of river incision is able to satisfactorily account for all available data. The cosmogenic ages of the YMT also point out a particular behaviour of the migrating knickpoints, which apparently propagated on average more slowly in the main rivers than in the tributaries, in contradiction with the relation that makes knickpoint celerity

Tectonic Geomorphology.

Science.gov (United States)

Bull, William B.

1984-01-01

Summarizes representative quantitative tectonic-geomorphology studies made during the last century, focusing on fault-bounded mountain-front escarpments, marine terraces, and alluvial geomorphic surfaces (considering stream terraces, piedmont fault scarps, and soils chronosequences). Also suggests where tectonic-geomorphology courses may best fit…

Geocronología de los yacimientos achelenses de Pinedo y Cien Fanegas (Valle del Tajo) e implicaciones en la evolución fluvial en el entorno de Toledo (España)

DEFF Research Database (Denmark)

López-Recio, M.; Silva, P. G.; Roquero, E.

2015-01-01

This study presents the first geochronological data from several research projects focused on the chronostratigraphy of the Tagus fluvial terraces in the environs of Toledo city (Central Spain). The research is centered on Middle to Late Pleistocene fluvial terraces with palaeontological and Ache...

77 FR 58565 - Federal Property Suitable as Facilities To Assist the Homeless

Science.gov (United States)

2012-09-21

...-0577 Comments: 9'8 x 15'5 ; storage/office; fair conditions; need repairs California Terrace Kitchen... zone; alternative method to access Terrace Restroom Yosemite Nat'l Park-Curry Village Yosemite CA 95389...: 61201230012 Status: Excess Comments: Documented deficiencies; severe structural damage; entire roof destroyed...

Search Results | Page 3 | IDRC - International Development ...

International Development Research Centre (IDRC) Digital Library (Canada)

This project will allow researchers from Canada and Kenya to field trial a vaccine for contagious bovine pleuropneumonia. Project. ​Increasing millet production in South Asia. The challenge. Project. Nepal Terrace Farmers and Sustainable Agriculture Kits (CIFSRF Phase 2). This project will test terrace farming innovations ...

Carbon surface diffusion and SiC nanocluster self-ordering

International Nuclear Information System (INIS)

Pezoldt, J.; Trushin, Yu.V.; Kharlamov, V.S.; Schmidt, A.A.; Cimalla, V.; Ambacher, O.

2006-01-01

The process of the spatial ordering of SiC nanoclusters on the step edges on Si surfaces was studied by means of multi-scale computer simulation. The evolution of cluster arrays on an ideal flat surface and surfaces with terraces of various widths was performed by kinetic Monte Carlo (KMC) simulations based on quantitative studies of potential energy surfaces (PES) by molecular dynamics (MD). PES analysis revealed that certain types of steps act as strong trapping centres for both Si and C adatoms stimulating clusters nucleation. Spatial ordering of the SiC nanoclusters at the terrace edges can be achieved if the parameters of the growth process (substrate temperature, carbon flux) and substrate (steps direction and terrace widths) are adjusted to the surface morphology. Temperature ranges for growth regimes with and without formation of cluster chains were determined. Cluster size distributions and the dependence of optimal terrace width for self ordering on the deposition parameters were obtained

77 FR 26025 - Notice of Intent To Prepare a Environmental Impact Statement (EIS) for the HOPE SF Development at...

Science.gov (United States)

2012-05-02

... a Environmental Impact Statement (EIS) for the HOPE SF Development at Potrero Terrace and Potrero... Statement (EIR/EIS) for the HOPE SF Development at the Potrero Terrace and Potrero Annex Public Housing Development (Potrero HOPE SF Master Plan Project). The EIR/EIS will be a joint National Environmental Policy...

Evolution of the Kιzιlιrmak river and its interaction with the North Anatolian Fault, Turkey

Science.gov (United States)

Drab, L.; Hubert Ferrari, A.; Benedetti, L.; van der Woerd, J.

2010-12-01

The North Anatolian Fault (NAF) is a 1500km long dextral strike-slip fault, which accommodates the extrusion of the Anatolian Plate away from the Arabia/Eurasia collision zone at a rate of 20-25mm/yr. The fault strongly affects the whole drainage network and, especially, the Kιzιlιrmak River. The Kιzιlιrmak River is the longest river in Turkey (1350km); it formed during the Pliocene and rose in eastern Anatolia. The river drains a part of the Anatolian Plateau, crosses the North Anatolian Fault and the Pontides mountains before reaching the Black Sea. Whereas wide terraces are preserved along the Kιzιlιrmak River in the Anatolian Plateau, where a recent study (Dogan 2009) determines an incision rate of 0.08 mm/yr according to 40Ar/39Ar datations on basalts, no clear terraces can be mapped further North where the river incises through the Pontides Mountains. Our study focuses on the central part of the fault affected by the 280 km long 1943 Tosya earthquake rupture. In this area the NAF makes a wide convex arc about 100km south to the Black Sea coast, and offset by 30 km the Kιzιlιrmak River. Indeed, south of the NAF the Kιzιlιrmak River flows to North/East. Then it is deviated along the NAF in the Kargι pull-apart and flows to the East parallel to the fault for 30km before bending again to the North/East in the Kamil pull-apart. Around the two bends of the River three alluvial terraces can be mapped. The lowest one (10m high above the present river level) is preserved in the Kargι pull-apart. The two other ones (60 and 100m above the Kιzιlιrmak River) are situated further east in the Kamil pull-apart. The highest terrace is offset by at least 300m offset along the NAF. The ages of sampled terraces are constrained using 10Be and 36Cl cosmogenic dating methods. The in situ cosmogenic 36Cl exposure ages calculated apply from 22ka for the lowest terrace, to 100 ka for the highest terrace in the erosion preserved area. The highest terrace shows a

Temporal correlation of fluvial and alluvial sequences in the Makran Range, SE-Iran

Science.gov (United States)

Kober, F.; Zeilinger, G.; Ivy-Ochs, S.; Dolati, A.; Smit, J.; Burg, J.-P.; Bahroudi, A.; Kubik, P. W.; Baur, H.; Wieler, R.; Haghipour, N.

2009-04-01

The Makran region of southeastern Iran is an active accretionary wedge with a partially subaerial component. New investigations have revealed a rather complex geodynamic evolution of the Makran active accretionary wedge that is not yet fully understood in its entity. Ongoing convergence between the Arabian and Eurasian plates and tectonic activity since the late Mesozoic has extended all trough the Quaternary. We focus here on fluvial and alluvial sequences in tectonically separated basins that have been deposited probably in the Pliocene/Quaternary, based on stratigraphic classification in official geological maps, in order to understand the climatic and tectonic forces occurring during the ongoing accretionary wegde formation. Specifically, we investigate the influence of Quaternary climate variations (Pleistocene cold period, monsoonal variations) on erosional and depositional processes in the (semi)arid Makran as well as local and regional tectonic forces in the Coastal and Central Makran Range region. Necessary for such an analysis is a temporal calibration of alluvial and fluvial terrace sequences that will allow an inter-basin correlation. We utilize the exposure age dating method using terrestrial cosmogenic nuclides (TCN) due to the lack of otherwise datatable material in the arid Makran region. Limited radiocarbon data are only available for marine terraces (wave-cut platforms). Our preliminary 21Ne and 10Be TCN-ages of amalgamated clast samples from (un)deformed terrace and alluvial sequences range from ~250 ky to present day (modern wash). These ages agree in relative terms with sequences previously assigned by other investigations through correlation of Quaternary sequences from Central and Western Iran regions. However, our minimum ages suggest that all age sequences are of middle to late Pleistocene age, compared to Pliocene age estimates previously assigned for the oldest units. Although often suggested, a genetical relation and connection of those

Engineering geological mapping of Dar es Salaam city, Tanzania ...

African Journals Online (AJOL)

Two basic maps were prepared, namely, geomorphological and geological map depicts the spatial extent of the Neogene geological formations. Three distinct sandstone terraces could be distinguished in Dar es Salaam region at 0-15 m and 30 – 40 m above sea level. The terraces comprised sandstones fringed by coral ...

Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure

Science.gov (United States)

Poag, C.W.

2005-01-01

This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism. 

Quantifying Ancient Maya Land Use Legacy Effects on Contemporary Rainforest Canopy Structure

Directory of Open Access Journals (Sweden)

Jessica N. Hightower

2014-11-01

Full Text Available Human land use legacies have significant and long-lasting ecological impacts across landscapes. Investigating ancient (>400 years legacy effects can be problematic due to the difficulty in detecting specific, historic land uses, especially those hidden beneath dense canopies. Caracol, the largest (~200 km2 Maya archaeological site in Belize, was abandoned ca. A.D. 900, leaving behind myriad structures, causeways, and an extensive network of agricultural terraces that persist beneath the architecturally complex tropical forest canopy. Airborne LiDAR enables the detection of these below-canopy archaeological features while simultaneously providing a detailed record of the aboveground 3-dimensional canopy organization, which is indicative of a forest’s ecological function. Here, this remote sensing technology is used to determine the effects of ancient land use legacies on contemporary forest structure. Canopy morphology was assessed by extracting LiDAR point clouds (0.25 ha plots from LiDAR-identified terraced (n = 150 and non-terraced (n = 150 areas on low (0°–10°, medium (10°–20°, and high (>20° slopes. We calculated the average canopy height, canopy openness, and vertical diversity from the LiDAR returns, with topographic features (i.e., slope, elevation, and aspect as covariates. Using a PerMANOVA procedure, we determined that forests growing on agricultural terraces exhibited significantly different canopy structure from those growing on non-terraced land. Terraces appear to mediate the effect of slope, resulting in less structural variation between slope and non-sloped land and yielding taller, more closed, more vertically diverse forests. These human land uses abandoned >1000 years ago continue to impact contemporary tropical rainforests having implications related to arboreal habitat and carbon storage.

Second-hand smoke exposure in outdoor hospitality venues: Smoking visibility and assessment of airborne markers.

Science.gov (United States)

Sureda, Xisca; Bilal, Usama; Fernández, Esteve; Valiente, Roberto; Escobar, Francisco J; Navas-Acien, Ana; Franco, Manuel

2018-08-01

After the implementation of smoke-free policies in indoor hospitality venues (including bars, cafeterias, restaurants, and pubs), smokers may have been displaced to their outdoor areas. We aimed to study smoking visibility and second-hand smoke exposure in outdoor hospitality venues. We collected information on signs of tobacco consumption on entrances and terraces of hospitality venues in 2016 in the city of Madrid, Spain. We further measured airborne nicotine concentrations and particulate matter of less than 2.5 µm in diameter (PM2.5) in terraces with monitors by active sampling during 30 min. We calculated the medians and the interquartile ranges (IQR) of nicotine and PM2.5 concentrations, and fitted multivariate models to characterize their determinants. We found 202 hospitality venues between May and September (summer), and 83 between October and December 2016 (fall) that were opened at the time of observation. We found signs of tobacco consumption on 78.2% of the outdoor main entrances and on 95.1% of outdoor terraces. We measured nicotine and PM2.5 concentrations in 92 outdoor terraces (out of the 123 terraces observed). Overall median nicotine concentration was 0.42 (IQR: 0.14-1.59) μg/m 3 , and overall PM2.5 concentration was 10.40 (IQR: 6.76-15.47) μg/m 3 (statistically significantly higher than the background levels). Multivariable analyses showed that nicotine and PM2.5 concentrations increased when the terraces were completely closed, and when tobacco smell was noticed. Nicotine concentrations increased with the presence of cigarette butts, and when there were more than eight lit cigarettes at a time. Outdoor hospitality venues are areas where non-smokers, both employees and patrons, continue to be exposed to second-hand smoke. These spaces should be further studied and considered in future tobacco control interventions. Copyright © 2018 Elsevier Inc. All rights reserved.

Small fluctuations in epitaxial growth via conservative noise

International Nuclear Information System (INIS)

Patrone, Paul N; Wang Rongrong; Margetis, Dionisios

2011-01-01

We study the combined effect of growth (material deposition from above) and nearest-neighbor entropic and force-dipole interactions in a stochastically perturbed system of N line defects (steps) on a vicinal crystal surface in 1+1 dimensions. First, we formulate a general model of conservative white noise and derive simplified formulas for the terrace width distribution and terrace width correlations in the limit N → ∞ for small step fluctuations. Our general result expresses terrace width correlations as an interplay of noise covariance and step interaction strength. Second, we apply our formalism to two specific noise models which stem, respectively, from (i) the fluctuation-dissipation theorem for diffusion of adsorbed atoms; and (ii) the phenomenological consideration of deposition-flux-induced asymmetric attachment and detachment of atoms at step edges. In both cases of noise, we find that terrace width correlations decay exponentially with the step number difference; this behavior leads to vanishing correlations in the macroscopic limit. Our analysis may be used to (i) determine the noise in quasi-one-dimensional surfaces and (ii) assess the validity of previous mean field approximations.

Differentiating submarine channel-related thin-bedded turbidite facies: Outcrop examples from the Rosario Formation, Mexico

Science.gov (United States)

Hansen, Larissa; Callow, Richard; Kane, Ian; Kneller, Ben

2017-08-01

Thin-bedded turbidites deposited by sediment gravity flows that spill from submarine channels often contain significant volumes of sand in laterally continuous beds. These can make up over 50% of the channel-belt fill volume, and can thus form commercially important hydrocarbon reservoirs. Thin-bedded turbidites can be deposited in environments that include levees and depositional terraces, which are distinguished on the basis of their external morphology and internal architecture. Levees have a distinctive wedge shaped morphology, thinning away from the channel, and confine both channels (internal levees) and channel-belts (external levees). Terraces are flat-lying features that are elevated above the active channel within a broad channel-belt. Despite the ubiquity of terraces and levees in modern submarine channel systems, the recognition of these environments in outcrop and in the subsurface is challenging. In this outcrop study of the Upper Cretaceous Rosario Formation (Baja California, Mexico), lateral transects based on multiple logged sections of thin-bedded turbidites reveal systematic differences in sandstone layer thicknesses, sandstone proportion, palaeocurrents, sedimentary structures and ichnology between channel-belt and external levee thin-bedded turbidites. Depositional terrace deposits have a larger standard deviation in sandstone layer thicknesses than external levees because they are topographically lower, and experience a wider range of turbidity current sizes overspilling from different parts of the channel-belt. The thickness of sandstone layers within external levees decreases away from the channel-belt while those in depositional terraces are less laterally variable. Depositional terrace environments of the channel-belt are characterized by high bioturbation intensities, and contain distinctive trace fossil assemblages, often dominated by ichnofabrics of the echinoid trace fossil Scolicia. These assemblages contrast with the lower

Geo morphological setting and main technological features of new Middle and Upper Pleistocene sites in the Lower Manzanares River Valley (Madrid, Spain); Contexto geomorfologico y principales rasgos tecnologicos de nuevos yacimientos del Pleistoceno Medio y Superior en el Valle Inferior del Manzanares (Madrid, Espana)

Energy Technology Data Exchange (ETDEWEB)

Silva, P. G.; Lopez Recio, M.; Cuartero, F.; Baena, J.; Tapias, F.; Manzano, I.; Martin, D.; Morin, J.; Roquero, E.

2012-11-01

The archaeological works developed during the years 1996 in the site of Tafesa, 2005 in the 12 de Octubre Metro Station site and 2006 in the confluence of the Butarque Stream (Villaverde-Barrio de Butarque site) located south of the Madrid City (Spain), have provided new lithic assemblages. These assemblages have been stratigraphic ally contextualized in the Pleistocene deposits of the Lower Manzanares river valley within the so-called Manzanares Complex Terrace (TCMZ). This fluvial terrace constitutes an anomalous thickened (20-15m) deposit at {+-}22-16m above the present river thalweg mainly developed along the right (southern) valley margin. This fluvial level has been traditionally considered of middle Pleistocene age on the basis of the acheulian lithics and faunal assemblages typically located within its lower stratigraphic layers. Certainly, the Tafesa is a fluvial terrace site at {+-}22 m with acheulian industry and middle Pleistocene faunal remains at its lower sedimentary sequence. However, the upper sedimentary levels of this same terrace in the 12 de Octubre y Villaverde-Butarque sites throw lithic assemblages of the lower and upper Paleolithic belonging to upper Pleistocene, as suggested by the available set of TL and OSL dates for the zone. The analyses developed in this study indicate that the development of this thickened fluvial terrace started during the end of the middle Pleistocene, but also comprise the whole Oxygen Isotopic Stage OIS 5 during the upper Pleistocene. (Author) 95 refs.

Effort to Increase Oil Palm Production through Application Technique of Soil and Water Conservation

Directory of Open Access Journals (Sweden)

Kukuh Murtilaksono

2009-05-01

Full Text Available The study was carried out at block 375, 415, and 414 (block 1, 2, and 3 Afdeling III, Mangement Unit of Rejosari, PT Perkebunan Nusantara VII, Lampung from June 2005 until December 2007. Objective of the study is to examine the effect of soil and water conservation measurement, namely bund terrace and silt pit that are combined with retarded-water hole on production of oil palm. Sampled trees of each block were randomly selected as much as 36 trees. Parameters of vegetative growth (additional new frond, total of frond, number of new bunch, production (number of bunch, fresh fruit bunch (TBS, and average of bunch weigh (RBT were observed and recorded every two weeks. Production of palm oil of each block was also recorded every harvesting schedule of Afdeling. Tabular data were analyzed descriptively by logical comparison among the blocks as result of application of bund terrace and silt pit. Although the data of sampled trees were erratic, bund terrace and silt pit generally increasing number of frond, number of bunch, average of bunch weight, and fresh fruit bunch. Bund terrace gived the highest production of TBS (25.2 t ha-1 compared to silt pit application (23.6 t ha-1, and it has better effect on TBS than block control (20.8 t ha-1. Aside from that, RBT is the highest (21 kg at bund terrace block compared to silt pit block (20 kg and control block (19 kg.

Tailoring Si(100) substrate surfaces for GaP growth by Ga deposition: A low-energy electron microscopy study

Energy Technology Data Exchange (ETDEWEB)

Rienäcker, Michael; Borkenhagen, Benjamin, E-mail: b.borkenhagen@pe.tu-clausthal.de; Lilienkamp, Gerhard; Daum, Winfried [TU Clausthal, Institut für Energieforschung und Physikalische Technologien, Leibnizstraße 4, D-38678 Clausthal-Zellerfeld (Germany)

2015-08-07

For GaP-on-Si(100) heteroepitaxy, currently considered as a model system for monolithic integration of III–V semiconductors on Si(100), the surface steps of Si(100) have a major impact on the quality of the GaP film. Monoatomic steps cause antiphase domains in GaP with detrimental electronic properties. A viable route is to grow the III–V epilayer on single-domain Si(100) with biatomic steps, but preferably not at the expense of reduced terrace widths introduced by miscut substrates. We have performed in situ investigations of the influence of Ga deposition on the kinetics of surface steps and terraces of Si(100) at substrate temperatures above 600 °C by low-energy electron microscopy. Starting from nearly equally distributed T{sub A} and T{sub B} terraces of a two-domain Si(100) surface, submonolayer deposition of Ga results in a transformation into a surface dominated by T{sub A} terraces and biatomic D{sub A} steps. This transformation is reversible, and Si(100) with monoatomic steps is recovered upon termination of the Ga flux. Under conditions of higher coverages (but still below 0.25 monolayer), we observe restructuring into a surface with T{sub B} dominance, similar to the findings of Hara et al. [J. Appl. Phys. 98, 083515 (2005)]. The occurrence and mutual transformations of surface structures with different terrace and step structures in a narrow range of temperatures and Ga deposition rates is discussed.

Impact of land use change on soil carbon loss of the Sikkim Himalayan piedmont

Science.gov (United States)

Prokop, Pawel; Ploskonka, Dominik

2014-05-01

Natural and human causes of change in land use on soil carbon were studied at the outlet of the Tista River from the Sikkim Himalayas over the last 150 years. Analysis of topographic maps and satellite images indicates that the land reforms related to location of tea gardens in the piedmont caused rapid deforestation of terraces in the late 19th century. Continuous population growth after 1930 initiated the replacement of floodplain forest by rice cultivation. Both processes changed soil carbon content and intensified fluvial activity expressed through terrace erosion. The replacement of natural forest by tea cultivation reduced the soil carbon content within terraces from 1.95 kg to 1.77 kg (in 1 m of topsoil) respectively. The replacement of natural forest by rice reduced the soil carbon content within floodplains from 0.42 kg to 0.23 kg (in 1 m topsoil) respectively. Much more dangerous, was terrace erosion leading to permanent removal of sediment including soil. The total loss of soil carbon in a 1 m thick soil layer due to conversion of 5 km2 forest to tea cultivation was about 900 t between 1930 and 2010. While the total soil carbon removed due to 1.8 km2 terrace erosion reached 3510 t in the same period. Result is the outcome of research project 2012/05/B/ST10/00309 of the National Science Centre (Poland).

A mass-wasting dominated Quaternary mountain range, the Coastal Range in eastern Taiwan

Science.gov (United States)

Hsieh, Meng-Long; Hogg, Alan; Song, Sheng-Rong; Kang, Su-Chen; Chou, Chun-Yen

2017-12-01

Fluvial bedrock incision, which creates topographic relief and controls hillslope development, has been considered the key medium linking denudation and tectonic uplift of unglaciated mountains. This article, however, shows a different scenario from the Coastal Range in eastern Taiwan. This range, with the steepness inherited from pre-orogenic volcanoes, has been subject to mass wasting even before its emergence above sea level no earlier than Middle Pleistocene. Numerous terraced alluvial fans/fan deltas record the ancient mass movements of the range, including rock avalanches. Multiple radiocarbon dates sequences not clearly related to the known climate-change events, and are believed to have been triggered mainly by severe rainfall events, large earthquakes, or their combinations. The resulting fluctuation of sediment yield has episodically changed river behavior, forming river terraces in catchments >1 km2. Alluvial terraces are typically exhibited close to the source ridges of mass movements, and strath terraces along the downstream parts of rivers. Both were created when enormous sediment supply had exceeded or matched the prevailing river transport capacity. This process, along with the protection by giant boulders from mass movement, disturbed the long-term incision trend of rivers in response to tectonic uplift. As a result, the observed Holocene bedrock incision at most sites has not kept pace with the tectonic uplift. The spatial contrast in mass-wasting histories further accounts for the great diversity of the terrace sequences, even in areas with similar tectonic and base-level conditions.

Two Late Pleistocene climate-driven incision/aggradation rhythms in the middle Dnieper River basin, west-central Russian Plain

Science.gov (United States)

Panin, Andrei; Adamiec, Grzegorz; Buylaert, Jan-Pieter; Matlakhova, Ekaterina; Moska, Piotr; Novenko, Elena

2017-06-01

In valleys of the River Seim and its tributaries in the middle Dnieper basin (west-central Russian Plain), two low terraces (T1, 10-16 m, and T0, 5-7 m above the river) and a floodplain (2-4 m) with characteristic large and small palaeochannels exist. A range of field and laboratory techniques was applied and ∼30 new numerical ages (OSL and 14C dates) were obtained to establish a chronology of incision and aggradation events that resulted in the current valley morphology. Two full incision/aggradation rhythms and one additional aggradation phase from the previous rhythm were recognized in the Late Pleistocene - Holocene climate cycle. The following events were detected. (1) Late MIS 5 - early MIS 4: aggradation of Terrace T1 following the deep incision at the end of MIS 6. (2) Late MIS 4 (40-30 ka): incision into Terrace T1 below the present-day river, formation of the main scarp in the bottom of the valley between Terrace T1 and Terrace T0/Floodplain levels. (3) MIS 2: aggradation of Terrace T0, lateral migrations of a shallow braided channel located few meters above the present-day river since ∼25 ka through the LGM. (4) 18-13 ka: incision into Terrace T0 below the modern river. Multiple-thread channels concentrated in a single flow that at some places formed large meanders. In the period 15-13 ka, high floods that rose above the present-day floods left large levees and overbank loams on Terrace T0. (5) Younger Dryas - Holocene transition: aggradation up to the modern channel level, transformation of large Late Glacial to small Holocene meanders. The established incision/aggradation rhythms are believed to be manifested over the Central Russian Plain outside the influence of ice sheets in the north and base level changes in the south. The two-phase deepening of the valley occurred in the last quarter of the last glacial epoch but can not be attributed directly to the glacial-interglacial transition. Both the detected incision events correspond to relatively

A cellular automata simulation study of surface roughening resulting from multi-atom etch pit generation during sputtering

Energy Technology Data Exchange (ETDEWEB)

Toh, Y S; Nobes, M J; Carter, G [Dept. of Electronic and Electrical Engineering, Univ. of Salford (United Kingdom)

1992-04-01

A two-dimensional square matrix of pseudo-atomic positions is erected and atom removal from the ''surface'' is effected randomly. Either single atoms or groups of atoms (to simulate multi-atom pit generation) are removed. The characteristics of the evolving roughened, terraced ''surface'' are evaluated as a function of the total number of atoms, or equivalent numbers of atomic layers, removed. These characteristics include the ''mean'' position of the sputtered surface, the standard deviation of terrace length about the mean and the form of the terrace length distributions. The results of the single-atom removal mode compare exactly with theoretical predictions in that, for large numbers of atoms removed the depth position of the mean of the terrace length distribution is identical to the mean sputtered depth and the standard deviation increases as the square root of this depth. For multi-atom removal modes (which cannot be predicted theoretically) the standard deviation also increases as the square root of the mean sputtered depth but with a larger proportionality constant. The implications of these observations for the evolution of surface morphology during high yield sputtering is discussed. (orig.).

FEASIBILITY OF SOIL AND WATER CONSERVATION TECHNIQUES ON OIL PALM PLANTATION

Directory of Open Access Journals (Sweden)

Kukuh Murtilaksono

2011-02-01

Full Text Available The objective of the study is to examine the effectiveness and feasibility of soil and water conservation techniques. The production of oil palm comprising the fresh fruit bunch, number of bunches, and average of bunch weight were recorded at every harvesting schedule. Tabular data were analyzed by logical comparison among the blocks as a result of application of bund terraces and silt-pit. Financial and sensi-tivity analysis of the effect of the techniques on FFB production were done. Bund terrace treatment was more effective (4.761 ton or 21.5% in increasing FFB production than the silt-pit treatment (3.046 ton or 13.4% when it is compared to that of the control block. The application of bund terraces and silt-pit also presents positive effects i.e. increases the average bunch weight and the number of bunch compared to that of the control. Furthermore, the financial analysis as well as sensitivity analysis shows that the bund terrace application is profitable and feasible (B/C = 3.06, IRR = 47% while the silt pit treatment is profitable but not feasible.

KMC Simulation of Surface Growth of Semiconductors

International Nuclear Information System (INIS)

Esen, M.

2004-01-01

In this work we have studied the growth and equilibration of semiconductor surfaces consisting of monoatomic steps separated by flat terraces using kinetic Monte Carlo method. Atomistic processes such as diffusion on terraces, attachment/detachment particles to/from step edges, attachment of particles from an upper terrace to a bounding step, diffusion of particles along step edges are considered. A rate equation for each, these processes is written and the overall transition probabilities are calculated where processes are ordered to make the distinction between slow and fast processes Iractal The interaction of steps is also included in the calculation of rate equations. The growth of such a surface is simulated when there is a particle flux to the surface. The rough of the surface and its dependence on both temperature and kinetic parameters such edge diffusion barrier are investigated. The formation of islands on terraces is prohibited and the distribution of their number and sizes are investigated as a function of temperature and appropriate kinetic parameters. In the absence of a flux to the surface, the equilibration of the surface is investigated paying particular attention to the top of the profile when the initial surface is a periodic profile where parallel monoatomic steps separated by terraces. It is observed that during equilibration of the profile, the topmost step disintegrates quickly and leads to many islands on the top of the profile due to. collision and annihilation of step edges of opposite sign. The islands then quickly disintegrate due to the line tension effect and this scenario repeats itself until the surface completely flattens

Investigation on the surface characterization of Ga-faced GaN after chemical-mechanical polishing

Energy Technology Data Exchange (ETDEWEB)

Gong, Hua [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Pan, Guoshun, E-mail: pangs@tsinghua.edu.cn [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Zhou, Yan; Shi, Xiaolei; Zou, Chunli; Zhang, Suman [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Shenzhen Key Laboratory of Micro/nano Manufacturing, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

2015-05-30

Highlights: • Tiny-sized nanoparticles were introduced in GaN CMP to realize a good surface. • The relationship between surface characterization and abrasive size was conducted. • An atomic step-terrace structure was achieved on GaN surface after CMP. • Pt/C catalyst nanoparticles were used in GaN CMP to get a higher MRR. - Abstract: The relationship between the surface characterization after chemical mechanical polishing (CMP) and the size of the silica (SiO{sub 2}) abrasive used for CMP of gallium nitride (GaN) substrates was investigated in detail. Atomic force microscope was used for measuring the surface morphology, pit feature, pit depth distribution, and atomic step-terrace structure. With the decrease of SiO{sub 2} abrasive size, the pit depth reduced and the atomic step-terrace structure became more whole with smaller damage area, resulting in smaller roughness. For tiny-sized SiO{sub 2} abrasive, an almost complete atomic step-terrace structure with 0.0523 nm roughness was achieved. On the other hand, in order to acquire higher removal, Pt/C nanoparticle was employed as a catalyst in CMP slurry. The result indicates that when Pt/C catalyst content was reached to 1.0 ppm, material removal rate was increased by 47.69% compared to that by none of the catalyst, and besides, the pit depth reduced and the surface atomic step-terrace structure was not destroyed. The Pt/C nanoparticle is proved to be the promising catalyst to the surface preparation of super-hard and inert materials with high efficiency and good surface.

Site observational work plan for the UMTRA project site at Shiprock, New Mexico

International Nuclear Information System (INIS)

1994-09-01

The site observational work plan (SOWP) for the Shiprock, New Mexico, Uranium Mill Tailings Remedial Action (UMTRA) Project Site is the initial document for developing site-specific activities to achieve regulatory compliance in the UMTRA Ground Water Project. The regulatory framework used to select the proposed ground water compliance strategies is presented along with a discussion of the relationship of this SOWP to other UMTRA Ground Water Project programmatic documents. The Shiprock site consists of two, interconnected hydrogeologic systems: the terrace system and the floodplain system. Separate compliance strategies are proposed for these two systems. The compliance strategy for the terrace aquifer is no remediation with the application of supplemental standards based on classification of the terrace aquifer as having Class III (limited-use) ground water. The compliance strategy for the floodplain aquifer is active remediation using a subsurface biological barrier. These strategies were selected by applying site-specific data to the compliance framework developed in the UMTRA Ground Water programmatic environmental impact statement (PEIS) (DOE, 1994a). The site conceptual model indicates that milling-related contamination has impacted the ground water in the terrace and floodplain aquifers. Ground water occurs in both aquifers in alluvium and in fractures in the underlying Cretaceous age Mancos Shale. A mound of ground water related to fluids from the milling operations is thought to exist in the terrace aquifer below the area where settling ponds were in use during the mill operations. Most of the water occurring in the floodplain aquifer is from recharge from the San Juan River

Nucleation on a stepped surface with an Ehrlich–Schwöbel barrier

International Nuclear Information System (INIS)

Chromcova, Z; Chvoj, Z; Tringides, M C

2013-01-01

During deposition on a stepped surface the growth mode depends on the conditions such as temperature T, deposition rate F and width of the terraces w. In this work we studied the influence of all the above mentioned characteristics using the kinetic Monte Carlo (kMC) technique. We concentrated on the conditions on the terrace at the moment of the first nucleation. The critical density of monomers for nucleation η m decreases with the width of the terrace and the nucleation starts at surprisingly low densities of monomers. We tested several definitions of the critical width for nucleation w c used in various articles in the past and we compared our results with results of the analytical steady-state mean-field model (Ranguelov and Altman 2007 Phys. Rev. B 75 245419). To check how the simplified assumption about the steady-state regime during deposition influences the resulting dependence of w c ≃ (D/F) κ , we set and also solved a time-dependent analytical model. This analytical model as well as kMC predict that w c ≃ (D/F) 1/5 . kMC simulation also shows that the Ehrlich–Schwöbel barrier has only limited influence on the nucleation on the stepped surface at conditions close to the nucleation regime. For all widths of terraces there is a critical value of the Ehrlich–Schwöbel barrier, and only below this critical value does the Ehrlich–Schwöbel barrier affect the final value of the density of nuclei. The results of the kMC are summarized in a semi-empirical analytical formula which describes the dependence of the step-flow growth and nucleation on the terrace width w, diffusion coefficient D and deposition rate F. In our simulations we tested two models of the stepped surface with different thicknesses of the step, both with an Ehrlich–Schwöbel barrier on the edge of the terrace. (paper)

Seismic influence in the Quaternary uplift of the Central Chile coastal margin, preliminary results.

Science.gov (United States)

Valdivia, D.; del Valle, F.; Marquardt, C.; Elgueta, S.

2017-12-01

In order to quantify the influence of NW striking potentially seismogenic normal faults over the longitudinal variation of the Central Chile Coastal margin uplift, we measured Quaternary marine terraces, which represent the tectonic uplift of the coastal margin. Movement in margin oblique normal faults occurs by co-seismic extension of major subduction earthquakes and has occurred in the Pichilemu fault, generating a 7.0 Mw earthquake after the 2010 8.8 Mw Maule earthquake.The coastal area between 32° and 34° S was selected due to the presence of a well-preserved sequence of 2 to 5 Quaternary marine terraces. In particular, the margin oblique normal NW-trending, SW-dipping Laguna Verde fault, south of Valparaiso (33° S) puts in contact contrasting morphologies: to the south, a flat coast with wide marine terraces is carved in both, Jurassic plutonic rocks and Neogene semi-consolidated marine sediments; to the north, a steeper scarp with narrower marine terraces, over 120 m above the corresponding ones in the southern coast, is carved in Jurassic plutonic rocks.We have collected over 6 months microseimic data, providing information on seismic activity and underground geometry of the Laguna Verde fault. We collected ca. 100 systematic measurements of fringes at the base of paleo coastal scarps through field mapping and a 5 m digital elevation model. These fringes mark the maximum sea level during the terrace's carving.The heights of these fringes range between 0 and 250 masl. We estimate a 0.7 mm/yr slip rate for the Laguna Verde fault based on the height difference between corresponding terraces north- and southward, with an average uplift rate of 0.3 mm/yr for the whole area.NW striking normal faults, besides representing a potential seismic threat to the near population on one of the most densely populated areas of Chile, heavily controls the spatial variation of the coastal margin uplift. In Laguna Verde, the uplift rate differs more than three times northward

Surface morphology of laser superheated Pb(111)

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z. H.; Lin, Bo; Zeng, X. L.; Elsayed-Ali, H. E.

1998-05-01

The step density on the vicinal Pb(111) surface after laser superheating and melting is investigated using reflection high-energy electron diffraction. The (00) beam profiles parallel and perpendicular to the incident beam are analyzed. For laser heating with ˜100 ps laser pulses, surface superheating does not significantly change the density of the steps and step edge roughness. A sudden increase in the average terrace width is observed after laser surface melting. The average terrace width and the string length at the step edge become as large as those at room temperature. The average terrace width at 573 K changes from 38±15 to 64±19 Å after laser surface melting, while the average string length at the step edge changes from 50±12 to 250±38 Å.

Survey of nine surface mines in North America. [Nine different mines in USA and Canada

Energy Technology Data Exchange (ETDEWEB)

Hayes, L.G.; Brackett, R.D.; Floyd, F.D.

1981-01-01

This report presents the information gathered by three mining engineers in a 1980 survey of nine surface mines in the United States and Canada. The mines visited included seven coal mines, one copper mine, and one tar sands mine selected as representative of present state of the art in open pit, strip, and terrace pit mining. The purpose of the survey was to investigate mining methods, equipment requirements, operating costs, reclamation procedures and costs, and other aspects of current surface mining practices in order to acquire basic data for a study comparing conventional and terrace pit mining methods, particularly in deeper overburdens. The survey was conducted as part of a project under DOE Contract No. DE-AC01-79ET10023 titled The Development of Optimal Terrace Pit Coal Mining Systems.

Environmental Assessment for the Solar Photovoltaic Array at Eglin Air Force Base, Florida

Science.gov (United States)

2014-01-24

fire hazard to solar panel array. ● Where applicable, reduce erosion using rough grade slopes or terrace slopes. ● Identify areas of existing...method would entail the installation of numerous smaller solar PV systems on the roofs of various buildings on the base. This alternative was...panel array.  Where applicable, reduce erosion using rough grade slopes or terrace slopes.  Identify areas of existing vegetation that the proponent

One-dimensional model of interacting-step fluctuations on vicinal surfaces: Analytical formulas and kinetic Monte Carlo simulations

Science.gov (United States)

Patrone, Paul N.; Einstein, T. L.; Margetis, Dionisios

2010-12-01

We study analytically and numerically a one-dimensional model of interacting line defects (steps) fluctuating on a vicinal crystal. Our goal is to formulate and validate analytical techniques for approximately solving systems of coupled nonlinear stochastic differential equations (SDEs) governing fluctuations in surface motion. In our analytical approach, the starting point is the Burton-Cabrera-Frank (BCF) model by which step motion is driven by diffusion of adsorbed atoms on terraces and atom attachment-detachment at steps. The step energy accounts for entropic and nearest-neighbor elastic-dipole interactions. By including Gaussian white noise to the equations of motion for terrace widths, we formulate large systems of SDEs under different choices of diffusion coefficients for the noise. We simplify this description via (i) perturbation theory and linearization of the step interactions and, alternatively, (ii) a mean-field (MF) approximation whereby widths of adjacent terraces are replaced by a self-consistent field but nonlinearities in step interactions are retained. We derive simplified formulas for the time-dependent terrace-width distribution (TWD) and its steady-state limit. Our MF analytical predictions for the TWD compare favorably with kinetic Monte Carlo simulations under the addition of a suitably conservative white noise in the BCF equations.

Applications of quaternary stratigraphic, soil-geomorphic, and quantitative geomorphic analyses to the evaluation of tectonic activity and landscape evolution in the Upper Coastal Plain, South Carolina

International Nuclear Information System (INIS)

Hanson, K.L.; Bullard, T.F.; Wit, M.W. de; Stieve, A.L.

1993-01-01

Geomorphic analyses combined with mapping of fluvial terraces and upland geomorphic surfaces provide new approaches and data for evaluating the Quaternary activity of post-Cretaceous faults that are recognized in subsurface data at the Savannah River Site in the Upper Coastal Plain of southwestern South Carolina. Analyses of longitudinal stream and terrace profiles, regional slope maps, and drainage basin morphometry indicate long-term uplift and southeast tilt of the site region. Preliminary results of drainage basin characterization suggests an apparent rejuvenation of drainages along the trace of the Pen Branch fault (a Tertiary reactivated reverse fault that initiated as a basin-margin normal fault along the northern boundary of the Triassic Dunbarton Basin). This apparent rejuvenation of drainages may be the result of nontectonic geomorphic processes or local tectonic uplift and tilting within a framework of regional uplift. Longitudinal profiles of fluvial terrace surfaces that are laterally continuous across the projected surface trace of the Pen Branch fault show no obvious evidence of warping or faulting within a resolution of ∼3 m. This combined with the estimated age of the terrace surfaces (350 ka to 1 Ma) indicates that if the Pen Branch fault is active, the Pleistocene rate of slip is very low (0.002 to 0.009 mm/yr)

14C age of the Quaternary deposits in Japan, 150

International Nuclear Information System (INIS)

Tsunoda, Kiyomi

1983-01-01

The distribution of old buried valley deposits in the Tama Valley was pointed out by investigators, and the detailed surveys were carried out formerly, but the comparison and the age of the deposits have not been clear. Terrace gravel bed which is considered as a part of old buried deposits was found in the Machiya River, one of the tributary of the Tama River, and its small branches. The peat bed in the lowest gravel bed contained small amount of wood pieces. The determination of the age of wood pieces was made, and the absolute age of more than 37,800 yBP was obtained. Generally, the formation of buried valleys progressed during glacial epoch or interglacial epoch, in which the change of climate and the change of erosion and deposit environment occurred. The Tachikawa terrace is the last terrace in Tama River Basin, and was formed during Wuerm Glacial epoch. The results of the determination of age indicated that the formation of the valley is older than the formation of the Tachikawa terrace. The distribution of buried valleys has been known in other rivers which have their sources in the mountain regions of the Kanto District. The studies of buried valleys have important meaning in the formation of mountain regions and plains. (Ishimitsu, A.)

Experimental restoration of a fen plant community after peat mining

Energy Technology Data Exchange (ETDEWEB)

Cobbaert, D.; Rochefort, L.; Price, J.S. [Univ. Laval, Sainte-Foy (Canada). Dept. de Phytologie

2004-11-01

Methods: The effectiveness of introducing fen plants with the application of donor diaspore material was tested. The donor diaspore material, containing seeds, rhizomes, moss fragments, and other plant propagules, was collected from two different types of natural fens. We tested whether the application of straw mulch would increase fen species cover and biodiversity compared to control plots without straw mulch. Terrace levels of different peat depths (15 cm, 40 cm, and 56 cm) were created to test the effects of different environmental site conditions on the success of re-vegetation. Results: Applying donor seed bank from natural fens was found to significantly increase fen plant cover and richness after the two growing seasons. Straw mulch proved to significantly increase fen plant richness. The intermediate terrace level (40 cm) had the highest fen plant establishment. Compared to reference sites, the low terrace level (15 cm) was richer in base cations, whereas the high terrace level (56 cm) was much drier. Conclusions: The application of donor diaspore material was demonstrated as an effective technique for establishing vascular fen plants. Further rewetting measures are considered necessary at the restoration site to create a fen ecosystem rather than simply restoring some fen species (Location: Riviere-du-Loup peatland, southern Quebec, Canada at 100 m a.s.l.)

A stochastic step flow model with growth in 1+1 dimensions

International Nuclear Information System (INIS)

Margetis, Dionisios

2010-01-01

Mathematical implications of adding Gaussian white noise to the Burton-Cabrera-Frank model for N terraces ('gaps') on a crystal surface are studied under external material deposition for large N. The terraces separate straight, non-interacting line defects (steps) with uniform spacing initially (t = 0). As the growth tends to vanish, the gaps become uncorrelated. First, simple closed-form expressions for the gap variance are obtained directly for small fluctuations. The leading-order, linear stochastic differential equations are prototypical for discrete asymmetric processes. Second, the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy for joint gap densities is formulated. Third, a self-consistent 'mean field' is defined via the BBGKY hierarchy. This field is then determined approximately through a terrace decorrelation hypothesis. Fourth, comparisons are made of directly obtained and mean-field results. Limitations and issues in the modeling of noise are outlined.

??????????? ???????? ???? ????-??????? BRGN

OpenAIRE

??????, ?. ?.; ?????????, ?. ?.; ??????, ?. ?.

2016-01-01

????. ??????????? ???????? ???? ??????????? ????-??????? BRGN ?????? ??????????? ??????? GeoTerrace ????????? ???????? ????????????? ???????????? ?????????? ????????????, ?? ???????????? ???????????? ?? ???????-??????? ?????????? ??? ?????????? ?????????? ????? ????? ?? ????????????? ????????????. ????????. ?? ??????? ???? ???????? ????????? ??????. ?? ????????? ?????? ??????????? 2 ?????? ????????????? ???????????? ?????? (P1 ?? P2). ??? ?????????? ?????? ????????? ????? ??????? ...

Estimation of Ravine Sediment production using MIKE 11 model, in the lower Le Sueur Watershed, Minnesota

Science.gov (United States)

Azmera, L. A.; Miralles-Wilhelm, F. R.; Melesse, A. M.; Belmont, P.; Jennings, C. E.; Thomas, A.; Khalif, F.

2008-12-01

A study of sediment dynamics in the Le Sueur River basin, southern Minnesota has been initiated with the goal of developing an integrated sediment budget. Preliminary analysis of the sediment load to the Minnesota River has shown that the Le Sueur River contributes substantial amount of the sediment transport and deposition. Many deeply incised ravines exist, especially towards the lower Le Sueur River. The ravines are believed to be one of the major sediment producing sources in the river basin. Hence the ravine sediment production should be accounted for in the sediment budget. This study concentrates on the hydrology of the ravines and evaluates the sediment budget at the ravine scale. Field observations from summer 2008 show that most of the bluffs along the main stem of both ravines are actively eroding. Also, landsliding of the steep ravine valley walls and rapid incision of the fluvial channels within the ravine are producing sediment. Several large fill terraces are present along the main stem, towards the mouth of the ravines. Recent incision through these extensive fill terraces may be another sediment producing source. Sediment storage in the ravines also occurs, behind woody debris jams as well as in locations where local baselevel has been raised by the insertion of a culvert. The sediment budget of the ravines would be quantified as the difference between the storage of sediment and the sum of sediments loads derived from the uplands, as well as the bluffs and terraces inside the ravines. Primary locations of major bluffs, terraces, gullies and drainage tiles in the gauged ravines were mapped using GPS. A database of major bluff, terraces, and drainage tiles was built in ArcGIS. Sediment samples from ravine heads, bluffs, terraces and ravine mouth were collected to study the grain size distribution and stratigraphy of major bluffs along the ravines. Sediment transport in the ravines will be modeled using MIKE 11 (DHI group), a dynamic, one

A Cultural Resources Reconnaissance at Lake Red Rock, Iowa

Science.gov (United States)

1984-05-01

vegetation and forest biomes that extended the length of the valley. It is implied that higher sinuosity, the graded topographies of the two lower terraces...11 B2t), the basal loess (II BgC ), proglacial lacustrine or ponding S sediments (III C), and the weathered Kansan till (IV C). Of these units, the...the poorly drained terrace settings and the generation of circumscribed aquatic biomes along this portion of the river. As illustrated by the

Life cycle environmental impacts of different construction wood waste and wood packaging waste processing methods

OpenAIRE

Manninen, Kaisa; Judl, Jáchym; Myllymaa, Tuuli

2016-01-01

This study compared the life cycle environmental impacts of different wood waste processing methods in three impact categories: climate impact, acidification impacts and eutrophication impacts. The wood waste recovery methods examined were the use of wood waste in terrace boards made out of wood composite which replace impregnated terrace boards, incineration of wood waste in a multi-fuel boiler instead of peat and the use of wood waste in the production of particleboard in either Finland or ...

The effect of the temperature in the formation of sputter-induced surface topography

International Nuclear Information System (INIS)

Zhang Jiping; Wang Zhenxia; Tao Zhenlan; Pan Jisheng

1992-01-01

The formation of the ion-induced surface topography has been studied extensively, but we know little of how to control the formation of the surface topography. In order to study further the mechanism of the formation of the surface topography at different target temperatures, we have selected two samples of the metal indium (99.99% purity) for study. The samples were bombarded by 27 keV Ar + ions at normal incidence, and the temperature was kept at 25 or 70 o C. The Ar + beam current was about 0.7 μA and the total dose was 1.4 x 10 18 ions cm -2 for each sample. The examination of the bombarded surface for each sample was carried out on an S-570 scanning electron microscope (SEM). In the bombarded surface of sample A at 25 o C, there are some terraces surrounded by deep ditches and among them there exhibit pebble-or sand-like structures. The terraces respond to the lowest-index planes of specimens in which the channel effect can be seen. The ditches are originated from grain boundaries, and the other part is high-index planes. In sample B at 70 o C, there are the same pebble-or sand-like structures, but instead of terraces there are some craters whose size and distribution is similar to that of the terraces in sample A. The middle of the crater is cavitated a little and its edge is raised. Like sample A, there are some deep ditches surrounding the craters. Comparing samples A and B, it can be accepted that these terraces and craters originated from the plane of the same orientation of grain. An interpretation of these observations is offered. (author)

Radon emanation rate in construction materials and various design of house

International Nuclear Information System (INIS)

Ahmad Asyraf Osman

2012-01-01

Indoor air quality are important factors that need to be addressed because it can affect the health and comfort of occupants in it. Among the major sources of indoor air pollution are radon gas. Radiological risk due to radon gas due to its intake into the human body is the major cause of lung cancer. This study was conducted to determine the radon emanation rate that occurs naturally in the building materials and its contains in several kinds of house. Construction materials studied are sand, gravel, cement and bricks. Terrace houses, double storey terrace houses, flats and wooden houses were studied in radon emanation in various types of houses. Radon emanation rates in building materials in a variety of home and the home measured using Sun Nuclear radon monitor (model 1029) and radon gas concentrations are measured in units of Bq m -3 . From the results, granites have recorded the highest radon emissions that is 2.67 μBq kg -1 s -1 , followed by sand with 2.53 μBq kg -1 s -1 . The bricks emission rate were recorded was 2.47 μBq kg -1 s -1 , while Cement recorded the lowest with only 1.46 μBq kg -1 s -1 . In study of radon in a variety of home, the results showed that the single storey terrace houses recorded the highest reading of 25.67 ± 4.96 Bq m -3 . First level Double storey terrace houses recorded 23.24 ± 3.72 Bq m -3 compared with a second level of two-storey terrace house which recorded emission rate of 16.43 ± 2.53 Bq m -3 . Flats were recorded the second lowest with only 13.07 ± 2.38 Bq m -3 . House that recorded the lowest reading was wooden houses that recorded 9.53 ± 1.96 Bq m -3 . (author)

Potential Energy Surface of NO on Pt(997: Adsorbed States and Surface Diffusion

Directory of Open Access Journals (Sweden)

N. Tsukahara

2012-01-01

Full Text Available The potential energy surface (PES of NO on Pt(997 has been elucidated: the adsorption states and diffusion processes of NO on Pt(997 at low coverage were investigated by using infrared reflection absorption spectroscopy (IRAS and scanning tunneling microscopy (STM. When NO molecules adsorb on a surface at a low temperature (11 K, each molecule transiently migrates on the surface from the first impact point to a possible adsorption site. We found that there are four stable adsorption sites for NO on Pt(997: a bridge site of the upper step, an fcc- (or hcp- hollow site of the terrace, an on-top site of the terrace, and an fcc-hollow site of the lower step. At higher temperatures above 45 K, NO molecules start to migrate thermally to more stable adsorption sites on a terrace, and they are finally trapped at the bridge sites of the step, which are the most stable among the four sites.

Detection of neotectonic deformations along the Rio do Peixe Valley, Western São Paulo State, Brazil, based on the distribution of late Quaternary allounits

Directory of Open Access Journals (Sweden)

Mario Lincoln Etchebehere

2005-11-01

Full Text Available Terrace deposits (34 10 ka were mapped in the Rio do Peixe valley and submitted to an allostratigraphic analysis. Three allomembers (viz. “A”, “B”, and “C” were established in the medium to lower river valley and other three allounits (allomembers “ L”, “M” and “N” were defined in the upper valley. It is probable tha “B” and “M” allomembers represent the same stratigraphic level. The spatial distribution of these allomember shows the influence of the Recent base-level changes, due to neotectonics events. Longitudinal cross-section o the Rio do Peixe valley shows that it is possible to define some areas with differential tectonic movements, tha includes uplift blocks (prone to erosion and terrace deposit destruction, and other areas with relative subsidence, controlling both the Recent alluvial plains and the preservation of some ancient terrace deposits. This scenery is in accordance with regional tectonic studies.

Shrub expansion at the forest–tundra ecotone: spatial heterogeneity linked to local topography

International Nuclear Information System (INIS)

Ropars, P; Boudreau, S

2012-01-01

Recent densification of shrub cover is now documented in many Arctic regions. However, most studies focus on global scale responses, yielding very little information on the local patterns. This research aims to quantify shrub cover increase at northern treeline (Québec, Canada) in two important types of environment, sandy terraces and hilltops (which cover about 70% of the landscape), and to identify the species involved. The comparison of a mosaic of two aerial photographs from 1957 (137 km 2 ) and one satellite image taken in 2008 (151 km 2 ) revealed that both hilltops and terraces recorded an increase in shrub cover. However, the increase was significantly greater on terraces than on hilltops (21.6% versus 11.6%). According to ground truthing, the shrub cover densification is associated mainly with an increase of Betula glandulosa Michx. The numerous seedlings observed during the ground truthing suggest that shrub densification should continue in the future. (letter)

Late Quaternary offset of alluvial fan surfaces along the Central Sierra Madre Fault, southern California

Science.gov (United States)

Burgette, Reed J.; Hanson, Austin; Scharer, Katherine M.; Midttun, Nikolas

2016-01-01

The Sierra Madre Fault is a reverse fault system along the southern flank of the San Gabriel Mountains near Los Angeles, California. This study focuses on the Central Sierra Madre Fault (CSMF) in an effort to provide numeric dating on surfaces with ages previously estimated from soil development alone. We have refined previous geomorphic mapping conducted in the western portion of the CSMF near Pasadena, CA, with the aid of new lidar data. This progress report focuses on our geochronology strategy employed in collecting samples and interpreting data to determine a robust suite of terrace surface ages. Sample sites for terrestrial cosmogenic nuclide and luminescence dating techniques were selected to be redundant and to be validated through relative geomorphic relationships between inset terrace levels. Additional sample sites were selected to evaluate the post-abandonment histories of terrace surfaces. We will combine lidar-derived displacement data with surface ages to estimate slip rates for the CSMF.

Segmented Coastal Uplift Along an Erosional Subduction Margin, Northern Hikurangi Fore Arc, North Island, New Zealand

Science.gov (United States)

Marshall, J. S.; Litchfield, N. J.; Berryman, K. R.; Clark, K.; Cochran, U. A.

2013-12-01

The Hikurangi subduction margin along North Island, New Zealand accommodates oblique convergence of the Pacific plate westward beneath the Australian plate at 45 mm/yr. Along the southern margin, frontal accretion and pronounced forearc uplift occur inboard of the subducting Hikurangi plateau. In the north, subduction erosion and segmented uplift occur inboard of subducting seamounts along the plateau flank. Prior workers have established a robust foundation for coastal terrace studies along the northern Hikurangi margin (e.g., Berryman et al., 1989; Ota et al., 1992; Berryman, 1993; Wilson et al., 2006, 2007; Clark et al., 2010; Litchfield et al, 2007, 2010). New field observations presented here provide additional constraints on terrace uplift along this erosional subduction margin. Along Raukumara Peninsula (north of Poverty Bay), multiple Holocene to late Pleistocene marine and fluvial terraces occur at varying elevations, recording differential uplift across six coastal segments from Gisborne to East Cape (Ota et al., 1992; Wilson et al., 2007). In this study, two to three late Pleistocene terraces were observed on rocky headlands within the first segment (Gisborne to Whangara) at elevations of 80-185 m above msl. Preliminary correlation with OIS 5a-e sea level high stands (80-125 ka) indicates net uplift at 1.2-1.5 m/ky. Uplifted Holocene wavecut platforms occur in steps along the seaward edge of these terraces, consistent with coseismic uplift. At Makorori Point, an uplifted bench occurs along the modern seacliff at 2.3 m above the cliff base. A fossil gastropod shell from paleo-beach gravels on the platform inner edge yielded a calibrated radiocarbon age of 1680 ×110 ybp. At Turihaua Point, a ≥1 m thick deposit of Holocene beach sands overlies an uplifted wavecut platform at ≥1.5 m above mean sea level. Carbonate-cemented beachrock at the base of the sand deposit yields a calibrated radiocarbon age of 2990 ×70 ybp. At Mahia Peninsula (between Poverty

Investigating the landscape of Arroyo Seco—Decoding the past—A teaching guide to climate-controlled landscape evolution in a tectonically active region

Science.gov (United States)

Taylor, Emily M.; Sweetkind, Donald S.; Havens, Jeremy C.

2017-05-19

IntroductionArroyo Seco is a river that flows eastward out of the Santa Lucia Range in Monterey County, California. The Santa Lucia Range is considered part of the central California Coast Range. Arroyo Seco flows out of the Santa Lucia Range into the Salinas River valley, near the town of Greenfield, where it joins the Salinas River. The Salinas River flows north into Monterey Bay about 40 miles from where it merges with Arroyo Seco. In the mountain range, Arroyo Seco has cut or eroded a broad and deep valley. This valley preserves a geologic story in the landscape that is influenced by both fault-controlled mountain building (tectonics) and sea level fluctuations (regional climate).Broad flat surfaces called river terraces, once eroded by Arroyo Seco, can be observed along the modern drainage. In the valley, terraces are also preserved like climbing stairs up to 1,800 feet above Arroyo Seco today. These terraces mark where Arroyo Seco once flowed.The terraces were formed by the river because no matter how high they are, the terraces are covered by gravel deposits exactly like those that can be observed in the river today. The Santa Lucia Range, Arroyo Seco, and the Salinas River valley must have looked very different when the highest and oldest terraces were forming. The Santa Lucia Range may have been lower, the Arroyo Seco may have been steeper and wider, and the Salinas River valley may have been much smaller.Arroyo Seco, like all rivers, is always changing. Some-times rivers flow very straight, and sometimes they are curvy. Sometimes rivers are cutting down or eroding the landscape, and sometimes they are not eroding but depositing material. Sometimes rivers are neither eroding nor transporting material. The influences that change the behavior of Arroyo Seco are mountain uplift caused by fault moment and sea level changes driven by regional climate change. When a stream is affected by one or both of these influences, the stream accommodates the change by

The Baltic Klint beneath the central Baltic Sea and its comparison with the North Estonian Klint

Science.gov (United States)

Tuuling, Igor; Flodén, Tom

2016-06-01

Along its contact with the Baltic Shield, the margin of the East European Platform reveals a well-developed, flooded terraced relief. The most striking and consistent set of escarpments at the contact of the Lower Palaeozoic calcareous and terrigenous rocks, known as the Baltic Klint (BK), extends from northwest of Russia to the Swedish island of Öland. Marine seismic reflection profiling in 1990-2004 revealed the central Baltic Sea Klint (BSK) section in detail and enabled comparison of its geology/geomorphology with a classical klint-section onshore, namely the North Estonian Klint (NEK). The conception of the BK onshore, which is based on the land-sea separating terraced relief in northern Estonia, is not fully applicable beneath the sea. Therefore, we consider that the BSK includes the entire terraced Cambrian outcrop. We suggest the term "Baltic Klint Complex" to include the well-terraced margin of the Ordovician limestone outcrop, which is weakly developed in Estonia. Because of a steady lithological framework of the bedrock layers across the southern slope of the Fennoscandian Shield, the central BSK in the western and the NEK in the eastern part of the Baltic Homocline have largely identical morphologies. The North Estonian Ordovician limestone plateau with the calcareous crest of the BK extends across the central Baltic Sea, whereas morphological changes/variations along the Klint base occur due to the east-westerly lithostratigraphic/thickness changes in the siliciclastic Cambrian sequence. The verge of the NEK, located some 30-50 m above sea level, starts to drop in altitude as its east-westerly course turns to northeast-southwest in western Estonia. Further westwards, the BK shifts gradually into southerly deepening (0.1-0.2°) layers as its crest drops to c. 150 m below sea level (b.s.l.) near Gotska Sandön. This course change is accompanied by a considerable decrease in thickness of the platform sedimentary cover, as below the central Baltic Sea the

Past sea level changes along the western continental margins of India: Evidences from morphology of the sea bed

Digital Repository Service at National Institute of Oceanography (India)

Vora, K.H.

-wide have been affected to a considerable extent by Pleistocene glaciations (Emery, 1968). The rate of sea-level rise has varied frequently and the sea-level still stands produced wave-cut terraces and platforms. In other words, the surface of a terrace... Merh (1992) while reviewing Quaternary sea level changes along India’s coasts observed that the Last Glacial Stage was a period of regression when the sea level went down to almost -150 m. With the advent of the Holocene, the sea started rising...

産学公連携による農作業着モンペッコとツナギッコの商品開発 : アグリアート・フェスティバル2016を事例として

OpenAIRE

水谷, 由美子; 小田, 玲子; 荒木, 麻耶

2017-01-01

This paper focuses on activities to promote Regional Creation from the field of fashion design. For three years from 2013 to this year, the team of Laboratory of Fashion Design and Planning at Yamaguchi Prefectural University has done fieldwork on Yuya, Nagato City, working on the branding of the rice terraces of Higashi Ushirobatake, which was selected as one of the Top100 Terraced Paddy Fields on Japan. At the same time, through joint research with Akie Abe(wife of Prime Minister Shinzo Abe...

Fallout radionuclide based techniques for assessing the effectiveness of soil conservation measures in different eroded regions of China

International Nuclear Information System (INIS)

Yu Hanqing; Li Yong; Liu Guoqiang; Li Junjie; Nguyen, M.L.; Funk, R.

2012-01-01

Using fallout radionuclide techniques (FRN), we investigated the extent of soil erosion and to quantify the beneficial effects of soil conservation measures at four sites (Xichang city in the Yangtze upriver, Yan'an in the Loess Plateau, Fengning in the wind erosion region of northern China, and Baiquan in black soil region of north-eastern China) extending from South West (SW) to North East (NE) China. At the Xichang site of SW-China, the combined use of FRN 137 Cs and 210 Pbex measurements demonstrated that the effectiveness of vegetation species in reducing soil erosion decreased in the following order: shrubs > trees with litter layer > grasses > trees without litter layer. At the Yan'an site of Loess Plateau, sediment production estimated by 137 Cs declined by 49% due to terracing and by 80% due to vegetated (with grass forest) compared to the cultivated hillslopes. Vegetated hillslope with grasses and forest increased soil organic matter (SOM) by 255%, soil available N (AN) by 198%, and soil available P (AP) by 18% while terracing increased SOM by 121%, soil AN by 103%, and soil AP by 162% compared with the entire cultivated hillslope. Both terracing and vegetating hillslopes were found to enhance soil porosity as shown by a decrease in soil bulk density (1.6% and 6.4%, respectively). At the Fengning site, data from 7 Be measurements indicated that four years of no tillage with high crop residues (50 ∼ 56 cm depth) reduced soil erosion by 44% and no tillage with low residues (25 cm depth) reduced soil erosion rates by 33% when compared with conventional tillage practices. At the Baiquan site in NE-China, soil loss as measured by 137 Cs tracer, decreased by 14% due to terracing and by 34% due to contoured tillage. Our results suggested that shrub cover and composite structure of forest and grass are the effective practices to control hillslope erosion in SW-China, while terracing forest-grass structure can greatly reduce soil erosion and improve soil quality

El espacio de bancales en el tramo inferior de la cuenca del Guiniguada: características ecoantrópicas y estado actual

Directory of Open Access Journals (Sweden)

Lidia Esther Romero Martín

2013-11-01

Full Text Available El tramo inferior de la cuenca del Guiniguada se caracteriza por la extensión y singularidad de los espacios de cultivo en terrazas. En este trabajo se describen las principales características geoecológicas y antrópicas de estas terrazas, con especial referencia al grado de deterioro de sus muros. El 40% de las unidades de terrazas tiene un grado de deterioro medio y alto. Se concluye que las pendiente, las forma de la ladera y litología, entre los parámetros ecológicos, y los uso y la edad transcurrida desde el abandono, entre los de carácter socio-económico, son los factores que condicionan, en distinta medida, el grado de conservación de las terrazas agrícolas.The low section of the Guiniguada basin is characterized by the extension and singularity of the spaces of culture in terraces. In this paper the principal geologic and anthropic characteristics of the above mentioned terraces are described, with special reference to the degree of deterioration of their walls. 40 % of the units of terraces has a degree of middle and high deterioration. The paper concludes that the slopes, the forms of the hillside and litology, among the ecological parameters, and the use and the age passed from the abandon, among the socio-economic parameters, are the factors that determine, in different degrees, the status of conservation of the agricultural terraces.

The role of organic intertile layer in abalone nacre

International Nuclear Information System (INIS)

Meyers, M.A.; Lim, C.T.; Li, A.; Hairul Nizam, B.R.; Tan, E.P.S.; Seki, Y.; McKittrick, J.

2009-01-01

Characterization of the growth surfaces removed from red and green abalone (Haliotis) shells shows a terraced cone mode of mineralization in which the organic layer is deposited periodically and regulates the formation of tiles with ∼ 500 nm thickness. The details of the mineral and organic layer surface are revealed by atomic force microscopy; the surface roughness and the thickness of the tiles in the terraces and organic intertile layer were measurement. Nanoindentation experiments at the top of the terraced cones confirm a hardness of the same order as that of completely mineralized surfaces. Indentation of the organic layer provides a force-deflection curve that can be expressed as tension on a centrally-loaded membrane. The results show that the dry organic layer is very stiff and deforms inelastically or cracks under the indenter, whereas in the fully hydrated state it shows a low modulus and strength and great extensibility. This strongly suggests that this organic interlayer acquires considerable strength and stiffness as a result of the drying process, which is consistent with a T g of approximately 200 deg. C for chitin. The chitin network that forms the structural component of the intertile layer is revealed and the orientation and spacing are measured. Terraced cones broken under the force of a flexing and shrinking organic layer enable the estimation of the tensile strength of the abalone when loaded through the fracture of the mineral bridges. Calculations show consistency with earlier tensile strength measurements of < 10 MPa.

Migration mechanisms of a faceted grain boundary

Science.gov (United States)

Hadian, R.; Grabowski, B.; Finnis, M. W.; Neugebauer, J.

2018-04-01

We report molecular dynamics simulations and their analysis for a mixed tilt and twist grain boundary vicinal to the Σ 7 symmetric tilt boundary of the type {1 2 3 } in aluminum. When minimized in energy at 0 K , a grain boundary of this type exhibits nanofacets that contain kinks. We observe that at higher temperatures of migration simulations, given extended annealing times, it is energetically favorable for these nanofacets to coalesce into a large terrace-facet structure. Therefore, we initiate the simulations from such a structure and study as a function of applied driving force and temperature how the boundary migrates. We find the migration of a faceted boundary can be described in terms of the flow of steps. The migration is dominated at lower driving force by the collective motion of the steps incorporated in the facet, and at higher driving forces by the step detachment from the terrace-facet junction and propagation of steps across the terraces. The velocity of steps on terraces is faster than their velocity when incorporated in the facet, and very much faster than the velocity of the facet profile itself, which is almost stationary. A simple kinetic Monte Carlo model matches the broad kinematic features revealed by the molecular dynamics. Since the mechanisms seem likely to be very general on kinked grain-boundary planes, the step-flow description is a promising approach to more quantitative modeling of general grain boundaries.

Preliminary Study of Long-term Geological Stability for HLW Disposal in Korea

International Nuclear Information System (INIS)

Hwang, Jae Ha; Kim, Ju Yong; Cho, Deung Lyong

2004-02-01

It was summarized previous works of the Al-in-hornblende geobarometer to quantify emplacement depths of the Cretaceous Bulgugsa granites and the Triassic-Jurassic Daebo granites in Korea. When calculated using the equation of Schmidt, the emplacement pressures of the Bulgugsa granites are less than 2.8 kb and those of the Daebo granites range from 3.4 to 7.8 kb. Assuming that the crustal thickness varies simply due to erosion and uplift, the crustal thickness of South Korea during the Jurassic can be calculated by adding average emplacement depth of the Jurassic granites to average thickness of present-day crust, which corresponds to about 50 km. The lower I terrace among the marine terraces had been formed in the Last Interglacial culmination stage(MIS 5e) by the amino-acid date, the identification of Ata tephra, the pollen assemblage and the relationships with the thalassostatic terrace of the Last Interglacial culmination stage, respectively. Ancient shoreline height of the lower marine terrace I is 18m on the whole southeastern coast of Korea. Therefore, if we assume that the sea level of the last Interglacial culmination period(125ka BP) was 6m higher than that of the present, the amount of net uplift since the last Interglacial culmination is about 12m, and if we suppose a constant-rate uplift, then the uplift rate in the southeastern coast area will be about 0.1m/ka

Dipole moments associated with edge atoms; a comparative study on stepped Pt, Au and W surfaces

International Nuclear Information System (INIS)

Besocke, K.; Krahl-Urban, B.; Wagner, H.

1977-01-01

Work function measurements have been performed on stepped Pt and Au surfaces with (111) terraces and on W surfaces with (110) terraces. In each case the work function decreases linearly with increasing step density and depends on the step orientation. The work function changes are attributed to dipole moments associated with the step edges. The dipole moments per unit step length are larger for open edge structures than for densely packed ones. The dipole moments for Pt are about twice as large as for Au and W. (Auth.)

From 3D to 2D Co and Ni Oxyhydroxide Catalysts: Elucidation of the Active Site and Influence of Doping on the Oxygen Evolution Activity

DEFF Research Database (Denmark)

Tripkovic, Vladimir; Hansen, Heine Anton; Vegge, Tejs

2017-01-01

Layered oxyhydroxides (ox-hys) of Ni and Co are among the most active catalysts for oxygen evolution in alkaline media. Their activities can be further tuned by delamination into single-layer oxide sheets or by means of doping. The active site for the reaction and how doping and delamination...... investigate the role of terrace and edge sites and use stability, catalytic activity, and electronic conductivity as evaluation criteria to pinpoint the best catalysts. We arrive at several important conclusions: the ox-hy surface is fully oxidized under oxygen evolution conditions, bulk terraces...

Before Smith’s Mill: Archaeological and Geological Investigations, Smithville Lake, Missouri. Volume 2,

Science.gov (United States)

1982-06-01

Investigations G.A.I. M sultmts’ field investigations comprised to oM r WnIt, 1) the excavation or testing of a selected series of a-haeological site" specified...this gulley (see below). The terrace area north of the channel scar is part of the T ter- race system, a series of paired terraces on either side of...Nebo [fill site, 21 CL II, and sinte" it Is (nsi’hered a single component site (Reid 1978), the two project I Ie pocint form, h con temporaleous

London forces in highly oriented pyrolytic graphite

Directory of Open Access Journals (Sweden)

L.V. Poperenko

2017-07-01

Full Text Available Surface of highly oriented pyrolytic graphite with terrace steps was studied using scanning tunneling microscopy with high spatial resolution. Spots with positive and negative charges were found in the vicinity of the steps. Values of the charges depended both on the microscope needle scan velocity and on its motion direction. The observed effect was theoretically explained with account of London forces that arise between the needle tip and the graphite surface. In this scheme, a terrace step works as a nanoscale diode for surface electric currents.

Time as An Important Soil-Forming Factor Influencing Modern and Ancient Magnetic Susceptibility Enhancement Along the Delaware River Valley, USA

Science.gov (United States)

Stinchcomb, G. E.; Peppe, D. J.; Driese, S. G.

2011-12-01

Magnetic susceptibility is an increasingly popular low-cost method for rapidly assessing paleoclimate and paleoenvironmental impact on buried soils. The goal of this study is to determine the primary influence(s) on soil magnetic susceptibility along floodplain, terrace and upland soils in the middle Delaware River Valley, USA, using environmental magnetic, pedologic, and stratigraphic techniques. Two-hundred thirty samples were collected from age-constrained sandy, quartz-rich, floodplain, terrace, and upland soils (Entisols, Inceptisols). A Kruskal-Wallis (K-W) and post-hoc Tukey-Kramer (T-K) (α=0.05) multiple comparisons analysis on 176 mass-specific low-field susceptibility (Xlf) assays show that A and B horizons are magnetically enhanced compared to C and E horizons (ptesting show that Xlf results, when grouped by floodplain-terrace designation (i.e., chronofunction) are significantly different (p<0.0001). The older T3 terrace and upland Xlf values (0.34±0.14 10^-6 m^3 kg^-1) are greater than the younger T2 terrace (0.18±0.06 10^-6 m^3 kg^-1) values, which are greater than modern floodplain (0.09±0.01 10^-6 m^3 kg^-1) Xlf values. These data suggest that longer intervals of soil formation enhance the Χlf value. This hypothesis is further supported when 159 Xlf values are plotted vs. age for the entire Holocene. A locally-weighted regression smoothing curve (LOESS) shows two distinct intervals of magnetic enhancement during previously established dry intervals, the early and late-middle Holocene. We hypothesize that prolonged drought during the early and middle Holocene reduced flood frequency and magnitude and the likelihood of soil burial, resulting in longer soil forming intervals and higher Xlf values. Although precipitation influences the Xlf signature, the results from this study suggest that the magnetic susceptibility values of well-drained buried floodplain soils along the Delaware River Valley are partly a function of time.

Optically stimulated luminescence (OSL) dating of shallow marine sediments to develop an analysis method of late Quaternary geodynamics

International Nuclear Information System (INIS)

Hataya, Ryuta; Shirai, Masaaki

2003-01-01

To develop an analysis method of geodynamics, we have examined the applicability of the OSL dating of marine terrace deposits. We have done the OSL dating, using the multiple-aliquot additive-dose technique, of shallow marine sediments from the upper part the Kioroshi Formation in Ibaraki Prefecture, which are correlated to Marine Oxygen Isotope Stage (MIS) 5e-5c. Marine terrace deposit consists mainly of shallow marine sediment. OSL ages of foreshore and foreshore-shoreface beds are 88-112 Ka, and are in good agreement with the geological/geomorphological data. On the other hand, OSL ages of the backshore bed are younger, and ones of the shoreface bed are older than geologically estimated ages. These results show that OPSL dating method can date shallow marine sediment using samples from foreshore and foreshore-shoreface beds, and that this method can distinguish terrace deposits formed in MIS5 and that in MIS7 by taking geomorphologic information into account. These results contribute to the characterization of long-term geological movement in coastal areas. (author)

Synthesis of BiFeO3 thin films on single-terminated Nb : SrTiO3 (111 substrates by intermittent microwave assisted hydrothermal method

Directory of Open Access Journals (Sweden)

Ivan Velasco-Davalos

2016-06-01

Full Text Available We report on a simple and fast procedure to create arrays of atomically flat terraces on single crystal SrTiO3 (111 substrates and the deposition of ferroelectric BiFeO3 thin films on such single-terminated surfaces. A microwave-assisted hydrothermal method in deionized water and ammonia solution selectively removes either (SrO34− or Ti4+ layers to ensure the same chemical termination on all terraces. Measured step heights of 0.225 nm (d111 and uniform contrast in the phase image of the terraces confirm the single termination in pure and Nb doped SrTiO3 single crystal substrates. Multiferroic BiFeO3 thin films were then deposited by the same microwave assisted hydrothermal process on Nb : SrTiO3 (111 substrates. Bi(NO33 and Fe(NO33 along with KOH served as the precursors solution. Ferroelectric behavior of the BiFeO3 films on Nb : SrTiO3 (100 substrates was verified by piezoresponse force microscopy.

High resolution morphobathymetric analysis and short-term evolution of the upper part of the Capbreton submarine canyon (south-east Bay of Biscay - French Atlantic coast)

Science.gov (United States)

Gillet, Hervé; Mazières, Alaïs; Mulder, Thierry; Cremer, Michel

2013-04-01

The Capbreton Canyon stands out by its deep incision through continental shelf and slope and its present turbidite activity. The head of the canyon is anthropically disconnected from the Adour River since 1310 AD, but is located close enough to the coast to allow a direct supply by longshore drift. Sedimentary processes in upper part of the Capbreton Canyon are poorly documented. Several evidences, including sandy slide scars in the head, suggest that this area plays a major role in triggering downstream gravity currents). However, no modern sedimentary activity in the upper canyon had so far been evidenced. Our study is based on the analysis and comparison of several sets of multibeam bathymetric data acquired in 1998, 2010 and 2012 (up to 1.5 m resolution). The morphobathymetric analysis brought the following key observations: - The upper part of the canyon is characterised by a meandering talweg underlined by two kinds of terraces: (1) small elongated terraces standing only 10 to 15 m above the talweg axis and (2) large terraces standing 45 to 100 m above the talweg axis. - The regular 1° longitudinal slope of the talweg is interrupted by several 10 m high knickpoints. - The floor of the talweg shows some rough areas scattered with transversal bedforms similar to the sediment waves described in the Monterey Canyon upper part (Smith et al, 2005). The morphological evolutions in the upper part of the canyon over the last 14 years especially affect the floor of the talweg: - Between 1998 and 2010, we observe a downstream succession of accretion areas (up to 11m thick) and erosion areas (reaching -25 m). The largest and highest terraces remain stable over this period, whereas the smallest and lowest elongated terraces show active sedimentation (+5 to +8 m). - Difference between 2010 and 2012 DEMs reveals three localized erosion spots corresponding to 200 m backward stepping of the knickpoints. Such observation confirms the active headward erosion in this part of

Ostracoda from Vestfold Hill lake terraces, Antarctica

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A.P.

typical deep water (psychrospheric) forms during Palaeocene to Oligocene as today but they were found in shallow (-45 to -37 m) depths here. Ostracodes are extremely rare as compared to the associated foraminiferal assemblage. Dissolution effect, loss...

The construction of fertility in al-Andalus. Geoarchaeology in Ricote (Murcia, Spain, 8th century AD)

Science.gov (United States)

Puy, Arnald

2013-04-01

Traditional irrigated terraces of Spain (known as 'huertas') are among the most emblematic and productive agricultural fields of the Mediterranean. Several of these huertas were first built by Arab and Berber tribes and clans that entered the Iberian Peninsula (al-Andalus) after 711 AD, coinciding with the spread of Islam during Middle Ages (>632 AD). One thousand and three hundred years after their construction they are still operative, presenting a topic case of sustainable and resilient agricultural areas. However, up until recently no data was available regarding the pre-existing features of the terrains where they were built, the timing of their construction nor their construction process. In this communication I will present the results of the study of a palaeosoil buried under an Andalusi irrigated terrace in the huerta of Ricote (Murcia, Spain). Soil micromorphology, physico-chemical analysis (Loss On Ignition, Magnetic Susceptibility, Particle Size Distribution, pH/Electrical Conductivity) and AMS dating allowed to determine that 1) Andalusi peasants selected a highly saline Hypercalcic Calcisol to build up the first irrigated terraces; 2) They clear the slope of bushes by fire; 3) They used the slope soil to build the terrace fill, possibly by inverting the original soil horizonation, and 4) According to the date obtained from the organic matter embedded in the topmost horizon of the palaeosoil (647-778 AD), the original Andalusi irrigated fields of Ricote were possibly built shortly after 711 AD. The communication, in sum, will show through a case study how past peasant societies transformed semi-arid environments to create highly productive agrarian areas.

Late Quaternary speleogenesis and landscape evolution in a tropical carbonate island: Pango la Kuumbi (Kuumbi Cave, Zanzibar

Directory of Open Access Journals (Sweden)

Nikos Kourampas

2015-09-01

Full Text Available Kuumbi Cave is one of a group of caves that underlie a flight of marine terraces in Pleistocene limestone in eastern Zanzibar (Indian Ocean. Drawing on the findings of geoarchaeological field survey and archaeological excavation, we discuss the formation and evolution of Kuumbi Cave and its wider littoral landscape. In the later part of the Quaternary (last ca. 250,000 years?, speleogenesis and terrace formation were driven by the interplay between glacioeustatic sea level change and crustal uplift at rates of ca. 0.10-0.20 mm/yr. Two units of backreef/reef limestone were deposited during ‘optimal’ (highest highstands, tentatively correlated with MIS 7 and 5; (mainly erosive marine terraces formed in these limestones in ‘suboptimal’ highstands. Kuumbi and other sub-terrace caves developed as flank margin caves, in the seaward portion of freshwater lenses during such ‘suboptimal’ highstands. Glacioeustacy-induced fluctuations of the groundwater table may have resulted in shifts from vadose (with deposition of well-developed speleothems to phreatic/epiphreatic conditions in these caves. At Kuumbi, Late Pleistocene (pre-20,000 cal. BP ceiling collapse initiated colluvial deposition near-entrance and opened the cave to large plants and animals, including humans. A phase of terminal Pleistocene human occupation ca. 18,500-17,000 cal. BP resulted in the deposition of a dense assemblage of Achatina spp. landsnails, alongside marine molluscs and mammal remains (including zebra, buffalo and other taxa now extinct on Zanzibar. The Holocene part of the cave stratigraphy near-entrance records phases of abandonment and intensified late Holocene human use.

The role of organic intertile layer in abalone nacre

Energy Technology Data Exchange (ETDEWEB)

Meyers, M.A., E-mail: mameyers@ucsd.edu [University of California, San Diego, La Jolla, California (United States); Lim, C.T.; Li, A.; Hairul Nizam, B.R.; Tan, E.P.S. [National University of Singapore, Singapore (Singapore); Seki, Y.; McKittrick, J. [University of California, San Diego, La Jolla, California (United States)

2009-10-15

Characterization of the growth surfaces removed from red and green abalone (Haliotis) shells shows a terraced cone mode of mineralization in which the organic layer is deposited periodically and regulates the formation of tiles with {approx} 500 nm thickness. The details of the mineral and organic layer surface are revealed by atomic force microscopy; the surface roughness and the thickness of the tiles in the terraces and organic intertile layer were measurement. Nanoindentation experiments at the top of the terraced cones confirm a hardness of the same order as that of completely mineralized surfaces. Indentation of the organic layer provides a force-deflection curve that can be expressed as tension on a centrally-loaded membrane. The results show that the dry organic layer is very stiff and deforms inelastically or cracks under the indenter, whereas in the fully hydrated state it shows a low modulus and strength and great extensibility. This strongly suggests that this organic interlayer acquires considerable strength and stiffness as a result of the drying process, which is consistent with a T{sub g} of approximately 200 deg. C for chitin. The chitin network that forms the structural component of the intertile layer is revealed and the orientation and spacing are measured. Terraced cones broken under the force of a flexing and shrinking organic layer enable the estimation of the tensile strength of the abalone when loaded through the fracture of the mineral bridges. Calculations show consistency with earlier tensile strength measurements of < 10 MPa.

[Characteristics of soil moisture variation in different land use types in the hilly region of the Loess Plateau, China].

Science.gov (United States)

Tang, Min; Zhao, Xi Ning; Gao, Xiao Dong; Zhang, Chao; Wu, Pu Te

2018-03-01

Soil water availability is a key factor restricting the ecological construction and sustainable land use in the loess hilly region. It is of great theoretical and practical significance to understand the soil moisture status of different land use types for the vegetation restoration and the effective utilization of land resources in this area. In this study, EC-5 soil moisture sensors were used to continuously monitor the soil moisture content in the 0-160 cm soil profile in the slope cropland, terraced fields, jujube orchard, and grassland during the growing season (from May to October) in the Yuanzegou catchment on the Loess Plateau, to investigate soil moisture dynamics in these four typical land use types. The results showed that there were differences in seasonal variation, water storage characteristics, and vertical distribution of soil moisture under different land use types in both the normal precipitation (2014) and dry (2015) years. The terraced fields showed good water retention capacity in the dry year, with the average soil moisture content of 0-60 cm soil layer in the growing season being 2.6%, 4.2%, and 1.8% higher than that of the slope cropland, jujube orchard, and grassland (all Pmoisture content of 0-60 cm soil layer in jujube orchard in the growing season was 2.9%, 3.8%, and 4.5% lower than that of slope cropland, terraced fields, and grassland, respectively (all Pmoisture in the surface layer (0-20 cm) and soil moisture in the middle layer (20-100 cm) under different land use types was large, and the trend for the similarity degree of soil moisture variation followed terraced fields > grassland > slope cropland > jujube orchard. The slope cropland in this area could be transformed into terraced fields to improve the utilization of precipitation and promote the construction of ecological agriculture. Aiming at resolving the severe water shortage in the rain-fed jujube orchard for the sustainable development of jujube orchard in the loess hilly

Landforms along transverse faults parallel to axial zone of folded mountain front, north-eastern Kumaun Sub-Himalaya, India

Science.gov (United States)

Luirei, Khayingshing; Bhakuni, S. S.; Negi, Sanjay S.

2017-02-01

The shape of the frontal part of the Himalaya around the north-eastern corner of the Kumaun Sub-Himalaya, along the Kali River valley, is defined by folded hanging wall rocks of the Himalayan Frontal Thrust (HFT). Two parallel faults (Kalaunia and Tanakpur faults) trace along the axial zone of the folded HFT. Between these faults, the hinge zone of this transverse fold is relatively straight and along these faults, the beds abruptly change their attitudes and their widths are tectonically attenuated across two hinge lines of fold. The area is constituted of various surfaces of coalescing fans and terraces. Fans comprise predominantly of sandstone clasts laid down by the steep-gradient streams originating from the Siwalik range. The alluvial fans are characterised by compound and superimposed fans with high relief, which are generated by the tectonic activities associated with the thrusting along the HFT. The truncated fan along the HFT has formed a 100 m high-escarpment running E-W for ˜5 km. Quaternary terrace deposits suggest two phases of tectonic uplift in the basal part of the hanging wall block of the HFT dipping towards the north. The first phase is represented by tilting of the terrace sediments by ˜30 ∘ towards the NW; while the second phase is evident from deformed structures in the terrace deposit comprising mainly of reverse faults, fault propagation folds, convolute laminations, flower structures and back thrust faults. The second phase produced ˜1.0 m offset of stratification of the terrace along a thrust fault. Tectonic escarpments are recognised across the splay thrust near south of the HFT trace. The south facing hill slopes exhibit numerous landslides along active channels incising the hanging wall rocks of the HFT. The study area shows weak seismicity. The major Moradabad Fault crosses near the study area. This transverse fault may have suppressed the seismicity in the Tanakpur area, and the movement along the Moradabad and Kasganj

Evolution of the morphology of the river Dragonja (SW Slovenia) due to land-use changes

Science.gov (United States)

Keesstra, S. D.; van Huissteden, J.; Vandenberghe, J.; Van Dam, O.; de Gier, J.; Pleizier, I. D.

2005-07-01

The effects of increasing agricultural land use on fluvial morphology have received much attention in fluvial research. However, in several regions in Europe, a reversing trend of decreasing agricultural activity and land abandonment, followed by reforestation, is observed. The response of fluvial morphology deserves attention because of its large impacts on landscape and riverine habitats. With the help of geomorphological mapping, multi-date aerial photography and a range of dating techniques, we reconstructed the evolution of the morphology of the riverbed and the floodplain of the Dragonja river in southwestern Slovenia. The results of this study show that the fluvial morphology in this Mediterranean catchment has changed considerably as a result of shifts in agricultural land use, in particular large-scale land abandonment in the second half of the 20th century. Until the first half of the 19th century, floodplain aggradation prevailed. Probably around 1870, a large erosion event occurred from which the floodplain did not fully recover. A terrace standing 2.5 m above the present floodplain was formed. Natural reforestation, due to depopulation since World War II, caused a reduction in discharge and sediment supply to the river. The decreased intensity and frequency of floods allowed invasion of the riverbed by vegetation, causing narrowing and incision of the riverbed. This resulted in the formation of a terrace, which now stands 1.5 m above the present-day river. This terrace is about 60 years old. However, the largest increase in forest area occurred since 1975, which intensified this process of riverbed narrowing and incision, creating a local terrace at 0.5 m at 0.5 m above the presently meandering river.

Mineralogy, stratigraphy, and provenance of soil coverbeds in the Kumara district, Westland

International Nuclear Information System (INIS)

Neall, V.E.; Stewart, R.B.; Wallace, R.C.; Williams, M.C.; Mew, G.

2001-01-01

The sand and silt mineralogy of four soils preserved on fluvioglacial outwash terraces at Kumara indicates that the main soil body is developed in up to 1 m of loessial coverbeds that accumulated subsequent to cessation of gravel terrace formation. Oxygen isotope abundances of the dominant mineral quartz in these soils show a higher temperature origin for the >250 micro-m fraction, consistent with derivation from local granodiorites. Finer quartz is of a mixed provenance origin consistent with the variety of rock types in the region. The finest quartz, <5 micro-m, of aerosolic origin, can be used as a proxy time record for the coverbed accumulations. The widespread 22 590 yr BP Aokautere Ash chronohorizon is preserved in three of the profiles, whilst wind redeposition of the glass shards is responsible for traces of rhyolitic glass in all subsequent horizons. Widespread landscape erosion is postulated either immediately before or during deposition of the K-1 terrace, so that similar subsequent coverbed sequences ae preserved on the K-1 and all older terraces in this district. Magnetic mineral assemblages in the profiles indicate a slightly different loessial provenance for the Cockeye, K-1, and K-2.1 profiles, but the K-2.2 is significantly different from the rest. This is probably a function of aeolian winnowing and variablity of source materials. In the past, different mountain catchments have connected with different lower river reaches, due to transcurrent movement on the Alpine Fault. This is interpreted as having led to changing provenance of river sediment supplying loess to local soils. (author). 39 refs.,10 figs., 4 tabs

Mineralogical In-situ Investigation of Acid-Sulfate Samples from the Rio Tinto River, Spain, with a Portable XRD/XRF Instrument

Science.gov (United States)

Sarrazin, P.; Ming, D. W.; Morris, R. V.; Fernandez-Remolar, D.; Amils, R.; Arvidson, R. E.; Blake, D.; Bish, D. L.

2007-01-01

A field campaign was organized in September 2006 by Centro de Astobiologica (Spain) and Washington University (St Louis, USA) for the geological study of the Rio Tinto river bed sediments using a suite of in-situ instruments comprising an ASD reflectance spectrometer, an emission spectrometer, panoramic and close-up color imaging cameras, a life detection system and NASA's CheMin 4 XRD/XRF prototype. The primary objectives of the field campaign were to study the geology of the site and test the potential of the instrument suite in an astrobiological investigation context for future Mars surface robotic missions. The results of the overall campaign will be presented elsewhere. This paper focuses on the results of the XRD/XRF instrument deployment. The specific objectives of the CheMin 4 prototype in Rio Tinto were to 1) characterize the mineralogy of efflorescent salts in their native environments; 2) analyze the mineralogy of salts and oxides from the modern environment to terraces formed earlier as part of the Rio Tinto evaporative system; and 3) map the transition from hematite-dominated terraces to the mixed goethite/salt-bearing terraces where biosignatures are best preserved.

Synthesis of BiFeO{sub 3} thin films on single-terminated Nb : SrTiO{sub 3} (111) substrates by intermittent microwave assisted hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Velasco-Davalos, Ivan; Ambriz-Vargas, Fabian; Kolhatkar, Gitanjali; Thomas, Reji, E-mail: ruediger@emt.inrs.ca, E-mail: reji.thomas@emt.inrs.ca; Ruediger, Andreas, E-mail: ruediger@emt.inrs.ca, E-mail: reji.thomas@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec, J3X1S2 (Canada)

2016-06-15

We report on a simple and fast procedure to create arrays of atomically flat terraces on single crystal SrTiO{sub 3} (111) substrates and the deposition of ferroelectric BiFeO{sub 3} thin films on such single-terminated surfaces. A microwave-assisted hydrothermal method in deionized water and ammonia solution selectively removes either (SrO{sub 3}){sup 4−} or Ti{sup 4+} layers to ensure the same chemical termination on all terraces. Measured step heights of 0.225 nm (d{sub 111}) and uniform contrast in the phase image of the terraces confirm the single termination in pure and Nb doped SrTiO{sub 3} single crystal substrates. Multiferroic BiFeO{sub 3} thin films were then deposited by the same microwave assisted hydrothermal process on Nb : SrTiO{sub 3} (111) substrates. Bi(NO{sub 3}){sub 3} and Fe(NO{sub 3}){sub 3} along with KOH served as the precursors solution. Ferroelectric behavior of the BiFeO{sub 3} films on Nb : SrTiO{sub 3} (100) substrates was verified by piezoresponse force microscopy.

Mineralogical and geological study of quaternary deposits and weathering profiles

Energy Technology Data Exchange (ETDEWEB)

Jeong, Gi Young; Lee, Bong Ho [Andong National Univ., Andong (Korea, Republic of)

2004-01-15

Movement history of a quaternary reverse fault cutting marine terrace deposit and tertiary bentonite in the Yangnammyon, Gyoungju city was studied by the mineralogical and microtextural analysis of the fault clays and weathered terrace deposits. Two types of fault clays were identified as greenish gray before the deposition of the marine terrace deposits and reddish brown after deposition. Greenish gray fault clay is composed mostly of smectite probably powdered from bentonite showing at least two events of movement from microtextures. After the bentonite was covered by quaternary marine gravel deposits, the reverse fault was reactivated cutting marine gravel deposits to form open spaces along the fault plane which allowed the hydrological infiltration of soil particles and deposition of clays in deep subsurface. The reddish brown 'fault' clays enclosed the fragments of dark brown ultrafine varved clay, proving two events of faulting, and slicken sides bisecting reddish brown clays suggest another faulting event in the final stage. Mineralogical and microtextural analysis of the fault clay show total five events of faulting, which had not been recognized even by thorough conventional paleoseismological investigation using trench, highlighting the importance of microtextural and mineralogical analysis in paleoseismology.

Impact Of Different Time Planting In Soybeans And Neem Seed Extract Application To Insect Population On Rice Field

Directory of Open Access Journals (Sweden)

Tamrin Abdullah

2015-08-01

Full Text Available Abstract The purpose of research is to study impact of different time planting of soybean and neem seed extract application to pest insect population on rice field. The research was used Random Block Design in three treatment of insecticides application i.e neem seed extract together with rice planting neem seed extract on soybean 17 days after rice planting synthetic insecticides on 17 days after rice planting Delthametrin on soybean and Chlorpirifos on rice respectively. Research was conducted in rice fields with irrigation channels. The land area is 0.8 hectares with extensive experiments each rice terraces approximately 900 m2 with separate by rice terraces for every treatment. Each treatment consisted of three groups and using nine rice terraces. Samples of the rice plant population is 25 plants per sample unit. The results was showed treatment by neem seed extract with different time planting of soybeans able to reduce number of pest insects populations such as N. virescens 80.38 N. lugens 67.17 S. incertulas 66.5 and L. oratorius 93.46 when compared to treatment with synthetic insecticides Delthamethrin and Chlorpyrifos.

Conductive atomic force microscopy study of InAs growth kinetics on vicinal GaAs (110)

International Nuclear Information System (INIS)

Tejedor, Paloma; Diez-Merino, Laura; Beinik, Igor; Teichert, Christian

2009-01-01

Conductive atomic force microscopy has been used to investigate the effect of atomic hydrogen and step orientation on the growth behavior of InAs on GaAs (110) misoriented substrates. Samples grown by conventional molecular beam epitaxy exhibit higher conductivity on [110]-multiatomic step edges, where preferential nucleation of InAs nanowires takes place by step decoration. On H-terminated substrates with triangular terraces bounded by [115]-type steps, three-dimensional InAs clusters grow selectively at the terrace apices as a result of a kinetically driven enhancement in upward mass transport via AsH x intermediate species and a reduction in the surface free energy.

Work on the extension of Restaurant No. 1

CERN Multimedia

GS Department

2010-01-01

The work on the extension of Restaurant No. 1 began on 12 April and is expected to take 6 months to complete. For safety reasons, a worksite perimeter fence has been erected on the terrace, and a watertight shielding wall has been put up inside the restaurant. Restaurant customers are requested to comply with the signs in place. Various activities associated with the work are likely to generate noise and dust. As the terrace is used by diners in the summer, such activities will be kept to a minimum during mealtimes. We should like to thank the customers of the restaurant for their understanding. GS/SEM Group

Evolution of the northern santa cruz mountains by advection of crust past a san andreas fault bend.

Science.gov (United States)

Anderson, R S

1990-07-27

The late Quaternary marine terraces near Santa Cruz, California, reflect uplift associated with the nearby restraining bend on the San Andreas fault. Excellent correspondence of the coseismic vertical displacement field caused by the 17 October 1989 magnitude 7.1 Loma Prieta earthquake and the present elevations of these terraces allows calculation of maximum long-term uplift rates 1 to 2 kilometers west of the San Andreas fault of 0.8 millimeters per year. Over several million years, this uplift, in concert with the right lateral translation of the resulting topography, and with continual attack by geomorphic processes, can account for the general topography of the northern Santa Cruz Mountains.

Using Remote Sensing and Spatial Analyses Techniques For Optimum Land Use Planning, West of Suez Canal, Egypt

International Nuclear Information System (INIS)

Elnahry, A.H.; Mohamed, E.S.; Nasar, N.

2008-01-01

The current study aims at using remote sensing (RS) and Geographic Information System (GIS) techniques for optimum landuse planning of the area located north Ismaillia - south Port Said Governorates on the western side of Suez Canal. It is bounded by longitudes 32 degree 10 and 32 degree 20 E and latitudes 30 0 4 rand 31 0 00' N. Great part of this area is under reclamation and suffering from improper landuse. Ten geomorphologic units were recognized i.e. clay flats, decantation basins, overflow basins, sand sheets, gypsiferous flats, old river terraces, sand flats, turtle backs, lake beds, and recent river terraces. Using US Soil Taxonomy, two soil orders could be identified; Entisols and Aridisols which are represented by ten great groups: Typic Haplosalids, Typic Haplogypsids, Typic Toriorthents, Vertic Argigypsids, Vertic Torrijluvents, Vertic Natrargids ,Typic Torripsamments, Typic Torrifluvens, Aquic Torriorthents and Typic Psammaquents. Surface and ground water with respect to salinity and alkalinity hazards were investigated ,where surface water of the main canals was classified as C2-S 1, C3-S 1 ,C4-S2 and C4-S4, meanwhile the ground water was classified as C3-S 1, C3 -S 1 ,C4-S2 ,C4-SI and C4-S4 .Optimum landuse planning of the studied area includes three approaches i.e., physical planning, optimum cropping pattern and other uses. Physical planning includes designing of three geospatial models. I-treatment plant site selection model. 2-central village site selection model and 3- shortest path for new Canal model. Current cropping pattern was obtained by matching the crop requirements with soil characteristics, where soils of high sand flats and low gypsiferrous flats are currently highly suitable (S2) for sugar beat, alfalfa and cotton, soils of low sand flats are currently highly suitable (S2) for olive, citrus and melon, soils of low recent river terraces are currently highly suitable (S2) for sugar beat, cotton, corn and rice ,soils of moderately

Erosion of continental margins in the Western Mediterranean due to sea-level stagnancy during the Messinian Salinity Crisis

Science.gov (United States)

Just, Janna; Hübscher, Christian; Betzler, Christian; Lüdmann, Thomas; Reicherter, Klaus

2011-02-01

High-resolution multi-channel seismic data from continental slopes with minor sediment input off southwest Mallorca Island, the Bay of Oran (Algeria) and the Alboran Ridge reveal evidence that the Messinian erosional surface is terraced at an almost constant depth interval between 320 and 380 m below present-day sea level. It is proposed that these several hundred- to 2,000-m-wide terraces were eroded contemporaneously and essentially at the same depth. Present-day differences in these depths result from subsidence or uplift in the individual realms. The terraces are thought to have evolved during one or multiple periods of sea-level stagnancy in the Western Mediterranean Basin. According to several published scenarios, a single or multiple periods of relative sea-level stillstand occurred during the Messinian desiccation event, generally known as the Messinian Salinity Crisis. Some authors suggest that the stagnancy started during the refilling phase of the Mediterranean basins. When the rising sea level reached the height of the Sicily Sill, the water spilled over this swell into the eastern basin. The stagnancy persisted until sea level in the eastern basin caught up with the western Mediterranean water level. Other authors assigned periods of sea-level stagnancy to drawdown phases, when inflowing waters from the Atlantic kept the western sea level constant at the depth of the Sicily Sill. Our findings corroborate all those Messinian sea-level reconstructions, forwarding that a single or multiple sea-level stagnancies at the depth of the Sicily Sill lasted long enough to significantly erode the upper slope. Our data also have implications for the ongoing debate of the palaeo-depth of the Sicily Sill. Since the Mallorcan plateau experienced the least vertical movement, the observed terrace depth of 380 m there is inferred to be close to the Messinian depth of this swell.

High natural erosion rates are the backdrop for enhanced anthropogenic soil erosion in the Middle Hills of Nepal

Science.gov (United States)

West, A. J.; Arnold, M.; Aumaître, G.; Bourlès, D. L.; Keddadouche, K.; Bickle, M.; Ojha, T.

2014-08-01

Although agriculturally accelerated soil erosion is implicated in the unsustainable environmental degradation of mountain environments, such as in the Himalaya, the effects of land use can be difficult to quantify in many mountain settings because of the high and variable natural background rates of erosion. In this study, we present new long-term denudation rates, derived from cosmogenic 10Be analysis of quartz in river sediment from the Likhu Khola, a small agricultural river basin in the Middle Hills of central Nepal. Calculated long-term denudation rates, which reflect background natural erosion processes over 1000+ years prior to agricultural intensification, are similar to present-day sediment yields and to soil loss rates from terraces that are well-maintained. Similarity in short- and long-term catchment-wide erosion rates for the Likhu is consistent with data from elsewhere in the Nepal Middle Hills, but contrasts with the very large increases in short-term erosion rates seen in agricultural catchments in other steep mountain settings. Our results suggest that the large sediment fluxes exported from the Likhu and other Middle Hills rivers in the Himalaya are derived in large part from natural processes, rather than from soil erosion as a result of agricultural activity. Because of the high natural background rates, simple comparison of short- and long-term rates may not reveal unsustainable soil degradation, particularly if much of the catchment-scale erosion flux derives from mass wasting. Correcting for the mass wasting contribution in the Likhu implies minimum catchment-averaged soil production rates of ~0.25-0.35 mm yr-1. The deficit between these production rates and soil losses suggests that terraced agriculture in the Likhu may not be associated with a large systematic soil deficit, at least when terraces are well maintained, but that poorly managed terraces, forest and scrubland may lead to rapid depletion of soil resources.

Effectiveness assessment of soil conservation measures in reducing soil erosion in Baiquan County of Northeastern China by using (137)Cs techniques.

Science.gov (United States)

Zhang, Qing-Wen; Li, Yong

2014-05-01

Accelerated soil erosion is considered as a major land degradation process resulting in increased sediment production and sediment-associated nutrient inputs to the rivers. Over the last decade, several soil conservation programs for erosion control have been conducted throughout Northeastern China. Reliable information on soil erosion rates is an essential prerequisite to assess the effectiveness of soil conservation measures. A study was carried out in Baiquan County of Northeastern China to assess the effectiveness of soil conservation measures in reducing soil erosion using the (137)Cs tracer technique and related techniques. This study reports the use of (137)Cs measurements to quantify medium-term soil erosion rates in traditional slope farmland, contour cropping farmland and terrace farmland in the Dingjiagou catchment and the Xingsheng catchment of Baiquan County. The (137)Cs reference inventory of 2532 ± 670 Bq m(-2) was determined. Based on the principle of the (137)Cs tracer technique, soil erosion rates were estimated. The results showed that severe erosion on traditional slope farmland is the dominant soil erosion process in the area. The terrace measure reduced soil erosion rates by 16% for the entire slope. Typical net soil erosion rates are estimated to be 28.97 Mg per hectare per year for traditional slope farmland and 25.04 Mg per hectare per year for terrace farmland in the Dingjiagou catchment. In contrast to traditional slope farmland with a soil erosion rate of 34.65 Mg per hectare per year, contour cultivation reduced the soil erosion rate by 53% resulting in a soil erosion rate of 22.58 Mg per hectare per year in the Xingsheng catchment. These results indicated that soil losses can be controlled by changing tillage practices from the traditional slope farmland cultivation to the terrace or contour cultivation.

The β → α phase transformation in plutonium

International Nuclear Information System (INIS)

Mitchell, T.E.; Hirth, J.P.; Schwartz, D.S.; Mitchell, J.N.

2013-01-01

The β → α transformation in plutonium is discussed in terms of the crystallography of the two phases and the resulting topological modeling of the β/α interface. There has been little microscopy work on the transformation, but it is probably martensitic. β-Pu is monoclinic I2/m, while α-Pu is monoclinic P2 1 /m. α-Pu has been described as a hexagonal close-packed pseudostructure with AB stacking of the (0 2 0) α planes with pseudo-close-packing along [1 0 0] α and two other directions. β-Pu is less obvious, but X-ray diffraction suggests that the (1 0 3) β planes, which are selected as the terrace plane, have the highest structure factor and are therefore among the closest-packed planes. Other pseudo-close-packed planes, such as {222 ¯ } β and {321 ¯ } β , could also act as terrace planes for the transformation. The (1 0 3) β planes have a pseudo-hexagonal grid of Pu atoms with AB stacking and pseudo-close-packing along [301 ¯ ] β and two other directions. A selection of terrace planes as (0 2 0) α //(1 0 3) β with disconnections along [100] α //[301 ¯ ] β provides the basis for topological modeling. The model predicts a habit plane that is ∼6° from the terrace plane. The extra Pu atoms in the β structure (17 for every 16 in α) are accommodated by having 16 (1 0 3) β planes transform into 17 (0 2 0) α planes at steps in the interface. Short-range interstitial diffusion of Pu atoms from β to α is required for the transformation to proceed. Possible lattice invariant deformation systems are discussed

Long-term changes to river regimes prior to late Holocene coseismic faulting, Canterbury, New Zealand

Science.gov (United States)

Campbell, Jocelyn K.; Nicol, Andrew; Howard, Matthew E.

2003-09-01

Two sites are described from range front faults along the foothills of the Southern Alps of New Zealand, where apparently a period of 200-300 years of accelerated river incision preceded late Holocene coseismic ruptures, each probably in excess of M w 7.5. They relate to separate fault segments and seismic events on a transpressive system associated with fault-driven folding, but both show similar evidence of off-plane aseismic deformation during the downcutting phase. The incision history is documented by the ages, relative elevations and profiles of degradation terraces. The surface dating is largely based on the weathering rind technique of McSaveney (McSaveney, M.J., 1992. A Manual for Weathering-rind Dating of Grey Sandstones of the Torlesse Supergroup, New Zealand. 92/4, Institute of Geological and Nuclear Sciences), supported by some consistent radiocarbon ages. On the Porters Pass Fault, drainage from Red Lakes has incised up to 12 m into late Pleistocene recessional outwash, but the oldest degradation terrace surface T I is dated at only 690±50 years BP. The upper terraces T I and T II converge uniformly downstream right across the fault trace, but by T III the terrace has a reversed gradient upstream. T II and T III break into multiple small terraces on the hanging wall only, close to the fault trace. Continued backtilting during incision caused T IV to diverge downstream relative to the older surfaces. Coseismic faulting displaced T V and all the older terraces by a metre high reverse scarp and an uncertain right lateral component. This event cannot be younger than a nearby ca. 500 year old rock avalanche covering the trace. The second site in the middle reaches of the Waipara River valley involves the interaction of four faults associated with the Doctors Anticline. The main river and tributaries have incised steeply into a 2000 year old mid-Holocene, broad, degradation surface downcutting as much as 55 m. Beginning approximately 600 years ago

Stabilization of the bank upstream on the north shore of the La Grande-1 installation

International Nuclear Information System (INIS)

Massiera, M.

1998-01-01

As part of the completion of the La Grande-1 project, construction of a 2,444 m long dyke was required on the north bank of the La Grande River. Sensitive marine clay, covered with deltaic and river sand and silt deposits was discovered which required special design features such as stabilization of the river bank, to avoid the possibility of disastrous retrogressive slides. This paper describes the geotechnical conditions of the northern terrace and the options available for stabilizing the river bank. Different phases of the construction of the stabilization dyke, including the excavated trench across the terrace, the instrumentation installed and the control measures taken, are also outlined. 8 refs., 1 tab., 3 figs

Topography and local modification of the HoBa2Cu3O/sub 7-//sub x/(001) surface using scanning tunneling microscopy

International Nuclear Information System (INIS)

Heinzelmann, H.; Anselmetti, D.; Wiesendanger, R.; Guentherodt, H.; Kaldis, E.; Wisard, A.

1988-01-01

The topography of the (001) surface of a high T/sub c/ superconducting HoBa 2 Cu 3 O/sub 7-//sub x/ single crystal was investigated in air using scanning tunneling microscopy. We found large, flat terraces separated by growth steps. The heights of these steps correspond to multiples of the c-axis lattice constant of 11.7 A of the perovskite structure. These steps have been verified by atomic force microscopy. On a smaller scale the flat terraces showed some fine structure with a corrugation height of 4 to 5 A and a lateral extent of several nanometers. In addition, we succeeded in creating nanometer-sized structures by increasing the sample bias voltage and tunneling current

Nepal Terrace Farmers and Sustainable Agriculture Kits (CIFSRF ...

International Development Research Centre (IDRC) Digital Library (Canada)

Partnering to support sustainable growth This project is a unique private-public partnership ... They will use a stall-based franchise model and local vendors. ... Call for new OWSD Fellowships for Early Career Women Scientists now open.

Absolute age determination of quaternary fault and formation

Energy Technology Data Exchange (ETDEWEB)

Cheong, Chang Sik; Lee, Kwang Sik; Choi, Man Sik [Korea Basic Science Institute, Taejon (Korea, Republic of)] (and others)

2003-03-15

Rb-Sr and K-Ar dating results for the fault rocks suggest the occurrence of recurrent fault activity around 80-95 Ma, 70 Ma, 50 Ma, 30 Ma and 23 Ma along the Yangsan fault zone. The apparent K-Ar ages tend to be older than Rb-Sr ages, probably indicating the effect of excess radiogenic Ar, which will be furthur investigated by Ar-Ar method. The OSL SAR protocol using 220 .deg. C cut-heat yields reproducible and stratigraphically consistent OSL ages ranging from 71 ka to 48 ka for beach deposits of the marine terrace No 2. The apparent OSL ages for the marine terrace No 3 range from 92 ka to 61 ka. These ages constrain the minimum age of the platform considering the underestimation effect resulted from deposition underwater. Therefore we regard the formation age of the terrace No 3 as MIS(Marine Isotopic Stage) 5c or 5e. Rb-Sr and K-Ar dating results for the fault rocks suggest the occurrence of recurrent fault activity around 40 Ma, 30 Ma and 23 Ma along the Ulsan fault zone. Relatively young (< 10 Ma) fault activities are recognized in the Oesa, Janghangri and Wonwonsa sites.

Potential impacts of damming the Juba Valley, western Somalia: Insights from geomorphology and alluvial history

Science.gov (United States)

Williams, Martin

2014-05-01

In 1988 plans were well advanced to dam the Juba River in western Somalia. The aims of the Baardheere Dam Project were to generate hydroelectric power for the capital Mogadishu, and to provide water for irrigation in the Juba Valley. A reconnaissance survey on foot along 500 km of the river upstream of the proposed dam site at Baardheere and detailed geomorphic mapping from air photos provided a basis for reconstructing the late Quaternary alluvial history of the river and for assessing the potential impact of the proposed dam. The Juba River rises in the Ethiopian Highlands and is the only river in Somalia that flows to the sea. Its history reflects climatic events in Ethiopia, where the Rift Valley lakes were very low during the LGM (21±2 ka), and high for about 5, 000 years before and after then. Cave deposits in Somalia indicate wetter conditions at 13, 10, 7.5 and 1.5 ka. Alluvial terraces in the Juba Valley range in age from late Pleistocene to late Holocene but only attain a few metres above the present floodplain. This is because the dry tributary valleys contain limestone caves and fissures that divert any high flows from the parent river underground, a process not known when the project was first approved. The oldest preserved terrace was cemented by calcrete by 40 ka. Alluvial gravels were deposited at the outlet of dry tributary valleys during times of episodic high-energy flow between 26 ka and 28 ka. Finely laminated shelly sands accumulated at 10 ka to form the 5 m terrace. The 2 m terrace was laid down 3.2 ka ago as a slackwater deposit. The lack of high-level alluvial terraces raises doubts over plans to dam the river, since rapid leakage would occur from side valleys and the reservoir would not attain the height needed to generate hydroelectric power. It would submerge all existing arable land along the river. Finally, the presence in the late Holocene alluvium of the sub-fossil gastropods Bulinus truncatus and Biomphalaria pfeifferi, which are

Orbital controls on paleo erosion rates in the Western Escarpment of the Andes at 13° latitude

Science.gov (United States)

Schlunegger, Fritz; Bekaddour, Toufik; Delunel, Romain; Norton, Kevin; Akçar, Naki; Vogel, Hendrik

2014-05-01

The formation of fluvial terrace sequences in mountainous areas requires that two boundary conditions have to be fulfilled. First, hilllslope material available for erosion needs to be sufficiently thick and abundant. Second stripping off of this regolith cover has to occur fast and within a short time period. Contrariwise, if hillslope erosion operates at a pace concordant with the fluvial regime and in equilibrium to the prevailing climate, then no terrace sequence will form. Here, we present a 10Be-based sediment budget from the cut-and-fill terrace sequences in the Pisco valley, and particularly the Minchin terrace sequence deposited between 48-36 ka, to illustrate how the erosional regime and the precipitation pattern has changed in response to orbitally-driven climate cycles. We find that the Minchin period was characterized by an erosional pulse along the Pacific coast during which denudation rates reached values as high as 600 mm/ka (provided that the lateral valley flanks have been the major sediment source) for a relatively short time span lasting a few thousands of years. This contrasts to the younger orbitally-controlled pluvial periods and the modern situation when 10Be-based sediment budgets yield nearly zero erosion at the Pacific coast. We interpret these contrasts to indicated different erosional conditions between the modern and the Minchin time. First, the sediment budget infers a precipitation pattern that is similar to the modern climate ca. 1000 km farther north near the boundary between Peru and Ecuador, where highly erratic and extreme El Niño-related precipitation are associated with landsliding and flooding along the coast. Second, the formation of a thick terrace sequence requires the supply of sufficient material through erosion on the catchment's hillslopes. It is likely that a relatively thick regolith sequence had accumulated before the start of the Minchin period, because this erosional epoch was preceded by a >50 ka-long time span

Spatio-temporal variability of soil water content on the local scale in a Mediterranean mountain area (Vallcebre, North Eastern Spain). How different spatio-temporal scales reflect mean soil water content

Science.gov (United States)

Molina, Antonio J.; Latron, Jérôme; Rubio, Carles M.; Gallart, Francesc; Llorens, Pilar

2014-08-01

As a result of complex human-land interactions and topographic variability, many Mediterranean mountain catchments are covered by agricultural terraces that have locally modified the soil water content dynamic. Understanding these local-scale dynamics helps us grasp better how hydrology behaves on the catchment scale. Thus, this study examined soil water content variability in the upper 30 cm of the soil on a Mediterranean abandoned terrace in north-east Spain. Using a dataset of high spatial (regular grid of 128 automatic TDR probes at 2.5 m intervals) and temporal (20-min time step) resolution, gathered throughout a 84-day period, the spatio-temporal variability of soil water content at the local scale and the way that different spatio-temporal scales reflect the mean soil water content were investigated. Soil water content spatial variability and its relation to wetness conditions were examined, along with the spatial structuring of the soil water content within the terrace. Then, the ability of single probes and of different combinations of spatial measurements (transects and grids) to provide a good estimate of mean soil water content on the terrace scale was explored by means of temporal stability analyses. Finally, the effect of monitoring frequency on the magnitude of detectable daily soil water content variations was studied. Results showed that soil water content spatial variability followed a bimodal pattern of increasing absolute variability with increasing soil water content. In addition, a linear trend of decreasing soil water content as the distance from the inner part of the terrace increased was identified. Once this trend was subtracted, resulting semi-variograms suggested that the spatial resolution examined was too high to appreciate spatial structuring in the data. Thus, the spatial pattern should be considered as random. Of all the spatial designs tested, the 10 × 10 m mesh grid (9 probes) was considered the most suitable option for a good

Annual Performance Report April 2015 Through March 2016 for the Shiprock, New Mexico, Disposal Site

Energy Technology Data Exchange (ETDEWEB)

Kautsky, Mark [USDOE Office of Legacy Management (LM), Washington, DC (United States); Miller, David [Navarro Research and Engineering, Oak Ridge, TN (United States)

2016-10-01

This annual report evaluates the performance of the groundwater remediation system at the Shiprock, New Mexico, Disposal Site (Shiprock site) for the period April 2015 through March 2016. The Shiprock site, a former uranium-ore processing facility remediated under the Uranium Mill Tailings Radiation Control Act, is managed by the U.S. Department of Energy (DOE) Office of Legacy Management. This annual report is based on an analysis of groundwater quality and groundwater level data obtained from site monitoring wells and the groundwater flow rates associated with the extraction wells, drains, and seeps. Background The Shiprock mill operated from 1954 to 1968 on property leased from the Navajo Nation. Remediation of surface contamination, including stabilization of mill tailings in an engineered disposal cell, was completed in 1986. During mill operation, nitrate, sulfate, uranium, and other milling-related constituents leached into underlying sediments and contaminated groundwater in the area of the mill site. In March 2003, DOE initiated active remediation of groundwater at the site using extraction wells and interceptor drains. At that time, DOE developed a baseline performance report that established specific performance standards for the Shiprock site groundwater remediation system. The Shiprock site is divided into two distinct areas: the floodplain and the terrace. The floodplain remediation system consists of two groundwater extraction wells, a seep collection drain, and two collection trenches (Trench 1 and Trench 2). The terrace remediation system consists of nine groundwater extraction wells, two collection drains (Bob Lee Wash and Many Devils Wash), and a terrace drainage channel diversion structure. All extracted groundwater is pumped into a lined evaporation pond on the terrace. Compliance Strategy and Remediation Goals As documented in the Groundwater Compliance Action Plan, the U.S. Nuclear Regulatory Commission–approved compliance strategy for the

Alluvial Aquifer

Data.gov (United States)

Kansas Data Access and Support Center — This coverage shows the extents of the alluvial aquifers in Kansas. The alluvial aquifers consist of unconsolidated Quaternary alluvium and contiguous terrace...

Helen Dilloni koduaed Dublinis / Virve Poom

Index Scriptorium Estoniae

Poom, Virve

2015-01-01

Tuntud iiri aiakujundaja Helen Dilloni koduaeda Dublini keskklinnas Sandford Terrace'il peetakse üheks parimaks linnaaiaks. Kaasaegsete aedade hulgas paistab see silma just oma erilisuse ja omanäolisusega

Interacting steps with finite-range interactions: Analytical approximation and numerical results

Science.gov (United States)

Jaramillo, Diego Felipe; Téllez, Gabriel; González, Diego Luis; Einstein, T. L.

2013-05-01

We calculate an analytical expression for the terrace-width distribution P(s) for an interacting step system with nearest- and next-nearest-neighbor interactions. Our model is derived by mapping the step system onto a statistically equivalent one-dimensional system of classical particles. The validity of the model is tested with several numerical simulations and experimental results. We explore the effect of the range of interactions q on the functional form of the terrace-width distribution and pair correlation functions. For physically plausible interactions, we find modest changes when next-nearest neighbor interactions are included and generally negligible changes when more distant interactions are allowed. We discuss methods for extracting from simulated experimental data the characteristic scale-setting terms in assumed potential forms.

Characterisation of anisotropic etching in KOH using network etch rate function model: influence of an applied potential in terms of microscopic properties

International Nuclear Information System (INIS)

Nguyen, Q D; Elwenspoek, M

2006-01-01

Using the network etch rate function model, the anisotropic etch rate of p-type single crystal silicon was characterised in terms of microscopic properties including step velocity, step and terrace roughening. The anisotropic etch rate data needed have been obtained using a combination of 2 wagon wheel patterns on different substrate and 1 offset trench pattern. Using this procedure the influence of an applied potential has been investigated in terms of microscopic properties. Model parameter trends show a good correlation with chemical/electrochemical reaction mechanism and mono- and dihydride terminated steps reactivity difference. Results also indicate a minimum in (111) terrace roughening which results in a peak in anisotropic ratio at the non-OCP applied potential of -1250 mV vs OCP

Upper Triassic spongiomorph and coral association dredged off the northwestern Australian shelf

Science.gov (United States)

Stanley, G. D.

Upper Triassic corals and spongiomorphs dredged during BMR Cruise 95 from the Rowley Terrace, offshore Canning Basin of northwestern Australia, indicate possible new occurrences of reef facies. These are comparable to counterparts known from the Norhtern Limestone Alps of central Europe. A branching spongiomorph, represented by the genus Spongiomorpha sp. and two coral taxa, Pamiroseris rectilamellosa (Winkler) and Retiophyllia tellae (Stoppani), are reported herein. Collectively, these fossils indicate a Late Triassic (Noria-Rhaetian) age. Although different in taxonomic composition, the fauna compares with one previously reported from a Late Triassic Ocean Drilling Project reef site (site 764) on the Wombat Plateau, some 350 km to the west. The Rowley Terrace occurrences may represent an eastward extension of the Wombat reefs, developed along the rifted margin of Gondwana.

76 FR 18573 - Notice of Availability of a Final Environmental Impact Statement for the Sunset Area Community...

Science.gov (United States)

2011-04-04

... shopping and commercial space; and green infrastructure. Sunset Terrace's redevelopment provides the... DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT [Docket No. FR-5513-N-01] Notice of Availability of a.... [[Page 18574

76 FR 5379 - Disease, Disability, and Injury Prevention and Control Special Emphasis Panel (SEP): Pregnancy...

Science.gov (United States)

2011-01-31

... Terrace Hotel, 659 Peachtree Street, NE., Atlanta, GA 30308, Telephone: (404) 898-8305. Status: The..., pursuant to Public Law 92-463. Matters To Be Discussed: The meeting will include the initial review...

Effects of adding illegal storeys to structural systems

Indian Academy of Sciences (India)

earth scientists, city planners, social scientists etc.) outlined the ... terrace, affects the dynamic behaviour of the building and changes its torsional irregularities. ..... practice, especially those constructed with reinforced concrete. Hence, on ...

75 FR 11889 - Consumer Advisory Council; Notice of Meeting of the Consumer Advisory Council

Science.gov (United States)

2010-03-12

..., in Dining Room E on the Terrace Level of the Martin Building. For security purposes, anyone planning... Board seeks its advice. Time permitting, the Council will discuss the following topics: Proposed rules...

Land subsidence and caprock dolines caused by subsurface gypsum dissolution and the effect of subsidence on the fluvial system in the Upper Tigris Basin (between Bismil Batman, Turkey)

Science.gov (United States)

Doğan, Uğur

2005-11-01

Karstification-based land subsidence was found in the Upper Tigris Basin with dimensions not seen anywhere else in Turkey. The area of land subsidence, where there are secondary and tertiary subsidence developments, reaches 140 km 2. Subsidence depth ranges between 40 and 70 m. The subsidence was formed as a result of subsurface gypsum dissolution in Lower Miocene formation. Although there are limestones together with gypsum and Eocene limestone below them in the area, a subsidence with such a large area is indicative of karstification in the gypsum. The stratigraphical cross-sections taken from the wells and the water analyses also verify this fact. The Lower Miocene gypsum, which shows confined aquifer features, was completely dissolved by the aggressive waters injected from the top and discharged through by Zellek Fault. This resulted in the development of subsidence and formation of caprock dolines on loosely textured Upper Miocene-Pliocene cover formations. The Tigris River runs through the subsidence area between Batman and Bismil. There are four terrace levels as T1 (40 m), T2 (30 m), T3 (10 m) and T4 (4-5 m) in the Tigris River valley. It was also found that there were some movements of the levels of the terraces in the valley by subsidence. The subsidence developed gradually throughout the Quaternary; however no terrace was formed purely because of subsidence.

Beaver assisted river valley formation

Science.gov (United States)

Westbrook, Cherie J.; Cooper, D.J.; Baker, B.W.

2011-01-01

We examined how beaver dams affect key ecosystem processes, including pattern and process of sediment deposition, the composition and spatial pattern of vegetation, and nutrient loading and processing. We provide new evidence for the formation of heterogeneous beaver meadows on riverine system floodplains and terraces where dynamic flows are capable of breaching in-channel beaver dams. Our data show a 1.7-m high beaver dam triggered overbank flooding that drowned vegetation in areas deeply flooded, deposited nutrient-rich sediment in a spatially heterogeneous pattern on the floodplain and terrace, and scoured soils in other areas. The site quickly de-watered following the dam breach by high stream flows, protecting the deposited sediment from future re-mobilization by overbank floods. Bare sediment either exposed by scouring or deposited by the beaver flood was quickly colonized by a spatially heterogeneous plant community, forming a beaver meadow. Many willow and some aspen seedlings established in the more heavily disturbed areas, suggesting the site may succeed to a willow carr plant community suitable for future beaver re-occupation. We expand existing theory beyond the beaver pond to include terraces within valleys. This more fully explains how beavers can help drive the formation of alluvial valleys and their complex vegetation patterns as was first postulated by Ruedemann and Schoonmaker in 1938. ?? 2010 John Wiley & Sons, Ltd.

Uplift of quaternary shorelines in eastern Patagonia: Darwin revisited

Science.gov (United States)

Pedoja, Kevin; Regard, Vincent; Husson, Laurent; Martinod, Joseph; Guillaume, Benjamin; Fucks, Enrique; Iglesias, Maximiliano; Weill, Pierre

2011-04-01

During his journey on the Beagle, Darwin observed the uniformity in the elevation of coastal Eastern Patagonia along more than 2000 km. More than one century later, the sequences of Quaternary shorelines of eastern Patagonia have been described and their deposits dated but not yet interpreted in terms of geodynamics. Consequently, we i) mapped the repartition of the Quaternary coastal sequences in Argentinean Patagonia, ii) secured accurate altitudes of shoreline angles associated with erosional morphologies (i.e. marine terraces and notches), iii) took into account previous chrono-stratigraphical interpretations in order to calculate mean uplift rates since ~ 440 ka (MIS 11) and proposed age ranges for the higher and older features (up to ~ 180 m), and iv) focused on the Last Interglacial Maximum terrace (MIS 5e) as the best constrained marine terrace (in terms of age and altitude) in order to use it as a tectonic benchmark to quantify uplift rates along the entire passive margin of Eastern South America. Our results show that the eastern Patagonia uplift is constant through time and twice the uplift of the rest of the South American margin. We suggest that the enhanced uplift along the eastern Patagonian coast that interested Darwin during his journey around South America on the Beagle could originate from the subduction of the Chile ridge and the associated dynamic uplift.

Spatially variable natural selection and the divergence between parapatric subspecies of lodgepole pine (Pinus contorta, Pinaceae).

Science.gov (United States)

Eckert, Andrew J; Shahi, Hurshbir; Datwyler, Shannon L; Neale, David B

2012-08-01

Plant populations arrayed across sharp environmental gradients are ideal systems for identifying the genetic basis of ecologically relevant phenotypes. A series of five uplifted marine terraces along the northern coast of California represents one such system where morphologically distinct populations of lodgepole pine (Pinus contorta) are distributed across sharp soil gradients ranging from fertile soils near the coast to podzolic soils ca. 5 km inland. A total of 92 trees was sampled across four coastal marine terraces (N = 10-46 trees/terrace) located in Mendocino County, California and sequenced for a set of 24 candidate genes for growth and responses to various soil chemistry variables. Statistical analyses relying on patterns of nucleotide diversity were employed to identify genes whose diversity patterns were inconsistent with three null models. Most genes displayed patterns of nucleotide diversity that were consistent with null models (N = 19) or with the presence of paralogs (N = 3). Two genes, however, were exceptional: an aluminum responsive ABC-transporter with F(ST) = 0.664 and an inorganic phosphate transporter characterized by divergent haplotypes segregating at intermediate frequencies in most populations. Spatially variable natural selection along gradients of aluminum and phosphate ion concentrations likely accounted for both outliers. These results shed light on some of the genetic components comprising the extended phenotype of this ecosystem, as well as highlight ecotones as fruitful study systems for the detection of adaptive genetic variants.

Flank tectonics of Martian volcanoes

International Nuclear Information System (INIS)

Thomas, P.J.; Squyres, S.W.; Carr, M.H.

1990-01-01

On the flanks of Olympus Mons is a series of terraces, concentrically distributed around the caldera. Their morphology and location suggest that they could be thrust faults caused by compressional failure of the cone. In an attempt to understand the mechanism of faulting and the possible influences of the interior structure of Olympus Mons, the authors have constructed a numerical model for elastic stresses within a Martian volcano. In the absence of internal pressurization, the middle slopes of the cone are subjected to compressional stress, appropriate to the formation of thrust faults. These stresses for Olympus Mons are ∼250 MPa. If a vacant magma chamber is contained within the cone, the region of maximum compressional stress is extended toward the base of the cone. If the magma chamber is pressurized, extensional stresses occur at the summit and on the upper slopes of the cone. For a filled but unpressurized magma chamber, the observed positions of the faults agree well with the calculated region of high compressional stress. Three other volcanoes on Mars, Ascraeus Mons, Arsia Mons, and Pavonis Mons, possess similar terraces. Extending the analysis to other Martian volcanoes, they find that only these three and Olympus Mons have flank stresses that exceed the compressional failure strength of basalt, lending support to the view that the terraces on all four are thrust faults

Climate and lake-level history of the northern Altiplano, Bolivia, as recorded in Holocene sediments of the Rio Desaguadero

Energy Technology Data Exchange (ETDEWEB)

Baucom, P.C.; Rigsby, C.A. [East Carolina Univ., Greenville, NC (United States). Dept. of Geology

1999-05-01

Strata exposed in terraces and modern cutbanks along the Rio Desaguadero contain a variety of lithofacies that were deposited in four distinct facies associations. These facies associations document a history of aggradation and downcutting that is linked to Holocene climate change on the Altiplano. Braided-stream, meandering-stream, deltaic and shoreline, and lacustrine sediments preserved in multi-level terraces in the northern Rio Desaguadero valley record two high-water intervals: one between 4,500 and 3,900 yr BP and another between 2,000 and 2,200 yr BP. These wet periods were interrupted by three periods of fluvial downcutting, centered at approximately 4,000 yr BP, 3,600 yr BP, and after 2,000 yr BP. Braided-river sediments preserved in a single terrace level in the southern Rio Desaguadero valley record a history of nearly continuous fluvial sedimentation from at least 7,000 yr BP until approximately 3,200 yr BP that was followed by a single episode (post-3,210 yr BP) of down-cutting and lateral migration. The deposition and subsequent fluvial downcutting of the northern strata was controlled by changes in effective moisture that can be correlated to Holocene water-level fluctuations of Lake Titicaca. The deposition and dissection of braided-stream sediments to the south are more likely controlled by a combination of base-level change and sediment input from the Rio Mauri.

Topographic features over the continental shelf off Visakhapatnam

Digital Repository Service at National Institute of Oceanography (India)

Rao, T.C.S.; Machado, T.; Murthy, K.S.R.

water depth and the continental shelfedge several interesting topographic features such as Terraces, Karstic structures associated with pinnacles and troughs and smooth dome shaped reef structures are recorded. The nature of these features...

77 FR 20051 - Meeting of the Compact Council for the National Crime Prevention and Privacy Compact

Science.gov (United States)

2012-04-03

... provides a legal framework for the establishment of a cooperative federal-state system to exchange such... will take place at The St. Anthony Hotel, 330 East Terrace, San Antonio, Texas, telephone (210) 227...

77 FR 25485 - Disease, Disability, and Injury Prevention and Control Special Emphasis Panel (SEP): Initial Review

Science.gov (United States)

2012-04-30

... Terrace Hotel, 659 Peachtree Street NE., Atlanta Georgia 30308. Status: The meeting will be closed to the... Determination of the Director, Management Analysis and Services Office, CDC, pursuant to Public Law 92-463...

76 FR 9780 - Consumer Advisory Council; Notice of Meeting

Science.gov (United States)

2011-02-22

... place at the Federal Reserve Board's offices in Washington, DC, in Dining Room E on the Terrace Level of... stabilization strategies. Proposed rules regarding debit card interchange fees and routing Members will discuss...

Anatomy of La Jolla submarine canyon system; offshore southern California

Science.gov (United States)

Paull, C.K.; Caress, D.W.; Lundsten, E.; Gwiazda, R.; Anderson, K.; McGann, M.; Conrad, J.; Edwards, B.; Sumner, E.J.

2013-01-01

An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall geometry of the La Jolla Canyon especially with respect to the pre-canyon host sediments. The floor of the axial channel is covered with unconsolidated sand similar to the sand on the shelf near the canyon head, lacks outcrops of the pre-canyon host strata, has an almost constant slope of 1.0° and is covered with trains of crescent shaped bedforms. The presence of modern plant material entombed within these sands confirms that the axial channel is presently active. The sand on the canyon floor liquefied during vibracore collection and flowed downslope, illustrating that the sediment filling the channel can easily fail even on this gentle slope. Data from the canyon walls help constrain the age of the canyon and extent of incision. Horizontal beds of moderately cohesive fine-grained sediments exposed on the steep canyon walls are consistently less than 1.232 million years old. The lateral continuity of seismic reflectors in minisparker profiles indicate that pre-canyon host strata extend uninterrupted from outside the canyon underneath some terraces within the canyon. Evidence of abandoned channels and point bar-like deposits are noticeably absent on the inside bend of channel meanders and in the subsurface of the terraces. While vibracores from the surface of terraces contain thin (< 10 cm) turbidites, they are inferred to be part of a veneer of recent sediment covering pre-canyon host sediments that underpin the terraces. The combined use of state of the art seafloor mapping and exploration tools provides a uniquely detailed view of the morphology within an active submarine canyon.

Ground-water data, 1969-77, Vandenberg Air Force Base area, Santa Barbara County, California

Science.gov (United States)

Lamb, Charles E.

1980-01-01

The water supply for Vandenberg Air Force Base is obtained from wells in the Lompoc Plain, San Antonio Valley, and Lompoc Terrace groundwater basins. Metered pumpage during the period 1969-77 from the Lompoc Plain decreased from a high of 3,670 acre-feet in 1969 to a low of 2,441 acre-feet in 1977, while pumpage from the San Antonio Valley increased from a low of 1 ,020 acre-feet in 1969 to a high of 1,829 acre-feet in 1977. Pumpage from the Lompoc Terrace has remained relatively constant and was 187 acre-feet in 1977. In the Barka Slough area of the San Antonio Valley, water levels in four shallow wells declined during 1976 and 1977. Water levels in observation wells in the two aquifers of the Lompoc Terrace ground-water basin fluctuated during the period, but show no long term trends. Chemical analyses or field determinations of temperature and specific conductance were made of 219 water samples collected from 53 wells. In the Lompoc Plain the dissolved-solids concentration in all water samples was more than 625 milligrams per liter, and in most was more than 1,000 milligrams per liter. The manganese concentration in analyzed samples equaled or exceeded the recommended limit of 50 micrograms per liter for public water supplies. Dissolved-solids concentrations increased with time in water samples from two wells east of the Air Force Base in San Antonio Valley. In the base well-field area, concentrations of dissolved solids ranged from 290 to 566 milligrams per liter. Eight analyses show manganese at or above the recommended limit of 50 milligrams per liter. In the Lompoc Terrace area dissolved-solids concentrations ranged from 470 to 824 milligrams per liter. Five new supply wells, nine observation wells, and two exploratory/observation wells were drilled on the base during the period 1972-77. (USGS)

Laurentide ice sheet meltwater routing along the Iro-Mohawk River, eastern New York, USA

Science.gov (United States)

Porreca, Charles; Briner, Jason P.; Kozlowski, Andrew

2018-02-01

The rerouting of meltwater as the configuration of ice sheets evolved during the last deglaciation is thought to have led to some of the most significant perturbations to the climate system in the late Quaternary. However, the complex pattern of ice sheet meltwater drainage off the continents, and the timing of rerouting events, remains to be fully resolved. As the Laurentide Ice Sheet (LIS) retreated north of the Adirondack Uplands of northeastern New York State during the last deglaciation, a large proglacial lake, Lake Iroquois, found a lower outlet that resulted in a significant flood event. This meltwater rerouting event, from outflow via the Iro-Mohawk River valley (southern Adirondack Mountains) to the spillway at Covey Hill (northeastern Adirondack Mountains), is hypothesized to have taken place 13.2 ka and disturbed meridional circulation in the North Atlantic Ocean. However, the timing of the rerouting event is not certain because the event has not been directly dated. With improving the history of Lake Iroquois drainage in mind, we obtained cosmogenic 10Be exposure ages on a strath terrace on Moss Island, along the Iro-Mohawk River spillway. We hypothesize that Moss Island's strath terrace became abandoned during the rerouting event. Six 10Be ages from the strath surface average 14.8 ± 1.3 ka, which predates the previously published bracketing radiocarbon ages of 13.2 ka. Several possibilities for the discrepancy exist: (1) the 10Be age accurately represents the timing of a decrease in discharge through the Iro-Mohawk River spillway; (2) the age is influenced by inheritance. The 10Be ages from glacially sculpted surfaces on Moss Island above the strath terrace predate the deglaciation of the site by 5 to 35 ky; and (3) the abandonment of the Moss Island strath terrace relates to knickpoint migration and not the final abandonment of the Iro-Mohawk River as the Lake Iroquois spillway. Further study and application of cosmogenic 10Be exposure dating in the

LiDAR Mapping of Earthquake Uplifted Paleo-shorelines, Southern Wairarapa Coast, North Island, New Zealand

Science.gov (United States)

Valenciano, J.; Angenent, J.; Marshall, J. S.; Clark, K.; Litchfield, N. J.

2017-12-01

The Hikurangi subduction margin along the east coast of the North Island, New Zealand accommodates oblique convergence of the Pacific Plate westward beneath the Australian plate at 45 mm/yr. Pronounced forearc uplift occurs at the southern end of the margin along the Wairarapa coast, onshore of the subducting Hikurangi plateau. Along a narrow coastal lowland, a series of uplifted Holocene marine terraces and beach ridges preserve a geologic record of prehistoric coseismic uplift events. In January 2017, we participated in the Research Experience for Undergraduates (REU) program of the NSF SHIRE Project (Subduction at Hikurangi Integrated Research Experiment). We visited multiple coastal sites for reconnaissance fieldwork to select locations for future in-depth study. For the coastline between Flat Point and Te Kaukau Point, we used airborne LiDAR data provided by Land Information New Zealand (LINZ) to create ArcGIS digital terrain models for mapping and correlating uplifted paleo-shorelines. Terrace elevations derived from the LiDAR data were calibrated through the use of Real Time Kinematic (RTK) GPS surveying at one field site (Glenburn Station). Prior field mapping and radiocarbon dating results (Berryman et al., 2001; Litchfield and Clark, 2015) were used to guide our LiDAR mapping efforts. The resultant maps show between four and seven uplifted terraces and associated beach ridges along this coastal segment. At some sites, terrace mapping and lateral correlation are impeded by discontinuous exposures and the presence of landslide debris, alluvial fan deposits, and sand dunes. Tectonic uplift along the southern Hikurangi margin is generated by a complex interaction between deep megathrust slip and shallow upper-plate faulting. Each uplifted Holocene paleo-shoreline is interpreted to represent a single coseismic uplift event. Continued mapping, surveying, and age dating may help differentiate between very large margin-wide megathrust earthquakes (M8.0-9.0+) and

Pollution characteristics and ecological risk assessment of heavy metals in three land-use types on the southern Loess Plateau, China.

Science.gov (United States)

Zhang, Yubin; Wu, Faqi; Zhang, Xinsheng; Cao, Ning

2017-08-25

The accumulation of heavy metals in agricultural soils has been the subject of great concern because these metals have the potential to be transferred to soil solutions and subsequently accumulate in the food chain. To study the persistence of trace metals in crop and orchard soils, representative surface soil samples were collected from terrace farmland that had been cultivated for various numbers of years (3, 8, 12, 15, and >20 years), terrace orchard land that had been cultivated for various numbers of years (4, 7, 10, 12, 15, 18, 25, and >30 years), and slope farmland with various gradients (3°, 5°, 8°, 12°, 15°, and 25°) and analyzed for heavy metals (As, Cr, Cu, Hg, Ni, and Zn). These samples were collected from Nihegou catchment of Chunhua county in the southern Loess Plateau of China. The six heavy metals demonstrated different trends with time or gradient in the three land-use types. The Cu and Zn contents of the soil were higher than the referee background values of the loessal soil, and the contents of Cr and Ni, and especially those of As and Hg, were lower. Cu was the only heavy metal that just met the Grade III Environmental Quality Standard for Soils of China, while the others reached grade I. Cu and Hg were considered contaminant factors and Hg was a moderate potential ecological risk factor in the catchment. Of the sites investigated, 89.5% fell into the category with a low degree of contamination (C d ) and rest were moderate, while all three land-use types had low potential ecological risk (RI). Changes of C d and RI were consistent with the cultivated time in the terrace farmland and terrace orchard land. Values of RI increased while C d decreased with the increasing of slope gradient in the slope farmland. Evaluating the ecological risk posed by heavy metals using more soil samples in a larger study area is necessary on the Loess Plateau of China.

Paleo erosion rates and climate shifts recorded by Quaternary cut-and-fill sequences in the Pisco valley, central Peru

Science.gov (United States)

Bekaddour, Toufik; Schlunegger, Fritz; Vogel, Hendrik; Delunel, Romain; Norton, Kevin P.; Akçar, Naki; Kubik, Peter

2014-03-01

Fluvial cut-and-fill sequences have frequently been reported from various sites on Earth. Nevertheless, the information about the past erosional regime and hydrological conditions have not yet been adequately deciphered from these archives. The Quaternary terrace sequences in the Pisco valley, located at ca. 13°S, offer a manifestation of an orbitally-driven cyclicity in terrace construction where phases of sediment accumulation have been related to the Minchin (48-36 ka) and Tauca (26-15 ka) lake level highstands on the Altiplano. Here, we present a 10Be-based sediment budget for the cut-and-fill terrace sequences in this valley to quantify the orbitally forced changes in precipitation and erosion. We find that the Minchin period was characterized by an erosional pulse along the Pacific coast where denudation rates reached values as high as 600±80 mm/ka for a relatively short time span lasting a few thousands of years. This contrasts to the younger pluvial periods and the modern situation when 10Be-based sediment budgets register nearly zero erosion at the Pacific coast. We relate these contrasts to different erosional conditions between the modern and the Minchin time. First, the sediment budget infers a precipitation pattern that matches with the modern climate ca. 1000 km farther north, where highly erratic and extreme El Niño-related precipitation results in fast erosion and flooding along the coast. Second, the formation of a thick terrace sequence requires sufficient material on catchment hillslopes to be stripped off by erosion. This was most likely the case immediately before the start of the Minchin period, because this erosional epoch was preceded by a >50 ka-long time span with poorly erosive climate conditions, allowing for sufficient regolith to build up on the hillslopes. Finally, this study suggests a strong control of orbitally and ice sheet forced latitudinal shifts of the ITCZ on the erosional gradients and sediment production on the western

Adsorbate-induced facetting reconstruction and self-organized domain patterning of vicinal Ag(111) surfaces; Adsorbatinduzierte richtungsabhaengige Facettierung und selbstorganisierte Domaenen-Musterbildung auf vizinalen Ag(111)-Oberflaechen

Energy Technology Data Exchange (ETDEWEB)

Schmitt, Stefan

2007-02-05

This thesis investigates structural aspects of adsorbate-induced facetting of vicinal Ag(111) surfaces. It is mainly based on scanning tunneling microscope (STM) and low energy electron diffraction (LEED) experiments performed under UHV conditions. The planar dye-molecule perylene-3,4,9,10-tetracarboxilicacid-dianhydride (PTCDA) adsorbs preferentially at the step edges of the 8.5 Ag(111) vicinal surfaces used in the experiments. It causes a facetting reconstruction by the formation of (111) terraces and facets with a high step density. Moreover, two distinct preferential inclinations of facets were observed, which can only be explained by the selective influence of the adsorbate superstructure. In terms of thermodynamics, the facetting reconstruction can be described as an orientational phase separation, adapted to the constraints of planar surfaces. This concept is capable of explaining the local facetting phenomena. The formalism used predicts an important role of nucleation kinetics. This aspect is taken into account by introducing an additional phase of mobile molecules (2D molecular gas), which cannot be measured directly. Furthermore, strong arguments for the appearance of a critical island size for the PTCDA/ Ag(111) superstructure were found. This work presents structural information of all stable superstructures of PTCDA on vicinal Ag(111) surfaces. Altogether 16 such superstructures were found, 3 of which had been observed and published before. Density and commensurability were found to systematically depend on the step-structure. The two preferred inclinations of facets are related to two characteristic types of domain boundaries of the herringbone superstructure to the adjacent (111)-terrace. On the (111) terraces, small islands of metastable superstructures were found. Facets and (111) terraces form a regular grating-like domain pattern with a variable structural width of 5 to 75 nm. STM measurements show direct evidence for a long-range interaction

Seismic and sequence stratigraphy of the central western continental margin of India: late-Quaternary evolution

Digital Repository Service at National Institute of Oceanography (India)

Karisiddaiah, S.M.; Veerayya, M.; Vora, K.H.

spanning different time scales. During the regressive periods, dipping strata were developed, while erosional surfaces and incised valleys were formed during the lowstands of sea level. Terraces, v-shaped depressions, lagoon-like structures observed...

Research Article Special Issue

African Journals Online (AJOL)

pc

2017-10-05

Oct 5, 2017 ... ... house, terraced 2 floors and. Author Correspondence, e-mail: ahmadshakir@ ... mental Healthcare, University Kuala Lumpur MESTECH(UniKL),. Kajang, Selangor .... ETS (cigarette) exposure at home. Yes. 35. 36.1. No. 62.

Human activity and landscape change at Adjiyska Vodenitsa, central Bulgaria

Science.gov (United States)

Chiverrell, R. C.; Archibald, Z.

2009-04-01

The Classical and early Hellenistic settlement located at Adjiyska Vodenitsa, near Vetren, in the centre of ancient Thrace, is somewhat unusual in displaying well-preserved evidence for the commercial and cultural interactions associated with a river port. The settlement evolved through a series of phases, with traces of activity emerging around the beginning of the fifth, advancing to a progressive close in the second century BCE. The settlement at Adjiyska Vodenitsa owed its raison d'être to river traffic, with the river as the primary means for importing commodities (non-local amphorae and roof tiles). The Pistiros inscription indicates that overland traffic was also important, presumably over the Rhodopes Mountains to the south. The relationship between the site and the Maritsa River is thus important. Located towards the head of the Maritsa basin downstream of the Momina Klissoura gorge near Belovo, the settlement is perched on a steeply-edged toe of the Vetren tributary alluvial fan, with the bluff trimmed by the migrating River Maritsa. The site is c.12-14 metres above the current bed of the River Maritsa, high and dry away from contemporary flooding, intriguing given evidence for flooding during occupation. The fluvial system has clearly been dynamic and changed much during the last 3000 years. Changes in the Maritsa have been constrained with radiocarbon ages obtained for two fan terrace levels. Active channel and overbank environments of the higher B1 terrace are dated to c. 520-400 cal. BC and provide a terminus post quem for the incision to the lower terrace (B2). The radiocarbon dating of basal contexts from the lower terrace palaeo-channels provides a terminus ante quem for abandonment of the higher terrace of cal. AD 1010-1150. Thus basal lowering and a shift to greater lateral channel activity appear to coincide with the abandonment of Adjiyska Vodenitsa. Upstream of the Momina Klissoura Gorge evidence for heightened geomorphic activity probably

Uplifting model of the Longmenshan mountain in the eastern margin of Tibetan plateau

Science.gov (United States)

Zhang, S.; Ding, R.; Mao, C.

2010-12-01

Longmenshan mountain is a vivid manifestation of the Cenozoic orogenesis in the eastern margin of the Tibetan plateau, and a key to understand the geodynamics of eastward extending of the plateau. Thus the uplift mechanism of Longmenshan mountain became a hot spot issue of geosciences about the Tibetan plateau. Two entirely different hypotheses, i.e., crustal shortening and lower crustal channel flow, were put forward, but the solution is open. Further discussion need our deeper understanding about the uplifting features of the Longmenshan mountain. Fortunately, the uplifting processes were recorded objectively by peneplains and river landforms. We first analysed the peneplains and pediplanes of Longmenshan mountain and its surrounding areas, and surveyed the terraces of Dadu river running across the mountain. Then we studied the uplifting features of the study areas in late Cenozoic time on the basis of landform geometries. Finaly we discussed the possible mechanisms for the uplifting. There are two levels of peneplains whose peneplanations may begin in early Cenozoic time and end at late Miocene when the final fluctuations of elevations were possibly less than one kilometers. The valley of Dadu river is incised into the peneplains and has a staircase of no less than ten levels of terraces. The highest terrace is a strath which was contemporary with the pediplane in the piedmont formed in late Pliocene or in early Pleistocene. Due to their originally flat features, the peneplains and the strath terraces were used as datum planes for judging neotectonic deformations. Since late Miocene, the southeastern side of Longmenshan mountain has been dominated by thrust-faulting with a total vertical displacement of about 4500 m against the Sichuan basin, meantime the northwest side has been maintained flexural uplift with syncline hinge approximately following the Longriba fault. As a landform barrier between Tibetan plateau and Sichuan basin, the crest lines of the

QUALIDADE DOS GRÃOS DE CAFÉ (Coffea arábica L. EM COCO PROCESSADOS POR VIA SECA

Directory of Open Access Journals (Sweden)

Rodrigo de Oliveira Simões

2008-01-01

Full Text Available The quality of coffee can be defined as a set of physical, chemical, sensory and security attributes that meet what the consumers want. The objective of this work was to evaluate and to compare the final quality of coffee produced by using the dry-process, using several procedures such as complete drying on cement terrace, suspended terrace, or their combination with mechanical horizontal rotary type driers. There was no significant change in the coffee quality obtained from any of the drying methods, however, it is known that the high percentage of cherry fruit, up from 90%, determined the high standard of quality of the drink and that this is influenced by the unripe fruits present in the product that cause undesirable fermentations and generate off-flavor.

A feasibility study of geogenic indoor radon mapping from airborne radiometric survey in northern Thailand

Energy Technology Data Exchange (ETDEWEB)

Wattananikorn, K. [Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)], E-mail: kittic@science.cmu.ac.th; Emharuthai, S. [Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wanaphongse, P. [Office of Atoms for Peace, Bangkok (Thailand)

2008-01-15

Experiments were carried out in seven test sites on three Quaternary alluvial and terrace deposit basins of northern Thailand, to test the possibility of using airborne equivalent uranium to predict geogenic indoor radon values of the region. The methodology was based on the correlation among soil gas permeability, soil radon concentration and indoor radon, as well as a relationship between soil radon and airborne uranium values. The methodology established works rather well when tested in areas of known indoor radon. Based on the predicted values that were obtained from this method, indoor radon in most areas of alluvial and terrace deposit basins of northern Thailand is less than 44Bq/m{sup 3}. There is no area in these basins where predicted indoor radon exceeds 74Bq/m{sup 3}.

Dynamics of interacting edge defects in copolymer lamellae

Science.gov (United States)

Dalnoki-Veress, Kari; McGraw, Joshua D.; Rowe, Ian D. W.

2011-03-01

It is known that terraces at the interface of lamella forming diblock copolymers do not make discontinuous jumps in height. Rather, their profiles are smoothly varying. The width of the transition region between two lamellar heights is typically several hundreds of nanometres, resulting from a balance between surface tension, chain stretching penalties, and the enthalpy of mixing. What is less well known in these systems is what happens when two transition regions approach one another. In this study, we show that time dependent experimental data of interacting copolymer lamellar edges is consistent with a model that assumes a repulsion between adjacent edges. The range of the interaction between edge defects is consistent with the profile width of noninteracting diblock terraces. Financial support from NSERC of Canada is gratefully acknowledged.

Large-scale uniform bilayer graphene prepared by vacuum graphitization of 6H-SiC(0001) substrates

Science.gov (United States)

Wang, Qingyan; Zhang, Wenhao; Wang, Lili; He, Ke; Ma, Xucun; Xue, Qikun

2013-03-01

We report on the preparation of large-scale uniform bilayer graphenes on nominally flat Si-polar 6H-SiC(0001) substrates by flash annealing in ultrahigh vacuum. The resulting graphenes have a single thickness of one bilayer and consist of regular terraces separated by the triple SiC bilayer steps on the 6H-SiC(0001) substrates. In situ scanning tunneling microscopy reveals that suppression of pit formation on terraces and uniformity of SiC decomposition at step edges are the key factors to the uniform thickness. By studying the surface morphologies prepared under different annealing rates, it is found that the annealing rate is directly related to SiC decomposition, diffusion of the released Si/C atoms and strain relaxation, which together determine the final step structure and density of defects.

Non-conservative dynamics of lattice sites near a migrating interface in a diffusional phase transformation

International Nuclear Information System (INIS)

Yang, T.; Gao, Y.; Wang, D.; Shi, R.P.; Chen, Z.; Nie, J.F.; Li, J.; Wang, Y.

2017-01-01

Migration of phase boundaries in crystalline solids eliminates one set of lattice sites and establishes another. Using a combination of phase field crystal modeling and crystallographic analysis, we present here a complete atomistic description of the migration mechanism of a high-index planar interface during a diffusional hexagon to square phase transformation. In particular we show that a terrace-step interface advances macroscopically in the form of growth ledges, while microscopically its migration occurs by opposite shearing on the terraces and a one-to-two splitting of lattice sites, giving a new class of lattice site correspondence and superabundant vacancies. In addition, a new approach capable of finding a critical nucleus with atomic resolution is developed by combining the phase field crystal energetics with the free-end nudged elastic band algorithm.

On the growth mechanisms of polar (100) surfaces of ceria on copper (100)

Science.gov (United States)

Hackl, Johanna; Duchoň, Tomáš; Gottlob, Daniel M.; Cramm, Stefan; Veltruská, Kateřina; Matolín, Vladimír; Nemšák, Slavomír; Schneider, Claus M.

2018-05-01

We present a study of temperature dependent growth of nano-sized ceria islands on a Cu (100) substrate. Low-energy electron microscopy, micro-electron diffraction, X-ray absorption spectroscopy, and photoemission electron microscopy are used to determine the morphology, shape, chemical state, and crystal structure of the grown islands. Utilizing real-time observation capabilities, we reveal a three-way interaction between the ceria, substrate, and local oxygen chemical potential. The interaction manifests in the reorientation of terrace boundaries on the Cu (100) substrate, characteristic of the transition between oxidized and metallic surface. The reorientation is initiated at nucleation sites of ceria islands, whose growth direction is influenced by the proximity of the terrace boundaries. The grown ceria islands were identified as fully stoichiometric CeO2 (100) surfaces with a (2 × 2) reconstruction.

Changes in Channel Geometry through the Holocene in the Le Sueur River, South-Central Minnesota, USA

Science.gov (United States)

Targos, Courtney Ann

Paleochannels preserved on terraces via meander cutoffs during an incisional period record the channel geometry and thus discharge at distinct points in time throughout a river's history. We measured paleochannel geometry on terraces throughout the Le Sueur River in south-central Minnesota, to track how channel geometry has changed over the last 13,400 years. A rapid drop in base level 13,400 yr B.P. triggered knickpoint migration and valley incision that is ongoing today. Since the 1800's, the area has developed rapidly with an increase in agriculture and associated drainage, directly impacting river discharge by increasing water input to the river. Five paleochannels were identified on terraces along the Le Sueur River from 1m-resolution lidar data. Ground Penetrating Radar (GPR) was used to obtain a subsurface image across paleomeanders to estimate the geometry of paleochannels. Paleochannel geometry and estimated discharge were then compared to modern conditions to assess how much change has occurred. Three lines were run across each paleochannel perpendicular to the historic water flow. Each of the 15 lines were processed using the EKKO Project 2 software supplied by Sensors and Software to sharpen the images, making it easier to identify the paleochannel geometry. Paleodischarge was determined using the Law of the Wall and Manning's Equation, using modern slope and roughness conditions. OSL samples were collected from overbank deposits on terraces to determine the time of channel abandonment, and supplemented with terrace ages obtained from a numerical model of valley incision. Paleodischarge coupled with depositional ages provide a history of flow conditions on the Le Sueur River. Results show an increase in channel widths from the time paleochannels were occupied to modern channel dimensions from an average of 20 meters to 35 meters. The change was not constant through time, as all paleochannels analyzed on terraces had similar-sized channels. The best way

Fundamentals of evaporation and condensation phenomena

International Nuclear Information System (INIS)

Munir, Z.A.

1979-01-01

Fundamental relationships governing evaporation and condensation processes are reviewed. The terrace-ledge-kink (TLK) model is discussed in terms of atomic steps comprising growth and evaporation of crystals. Recent results in the field are described

The Utilisation of Africa's Environmental Resources and the ...

African Journals Online (AJOL)

sulaiman.adebowale

2006-05-23

May 23, 2006 ... ment of Tanzania, one way of combating ecological and socio-economic ..... terracing, gully stabilisation, tree planting and so on as control meas- .... processes, and the current threats include housing construction, culti- vation ...

Signatures of Late Quaternary sea-level changes and Neo-tectonic activity over Visakhapatnam - Gopalpur shelf, east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Rao, K.M.; Reddy, N.P.C; PremKumar, M.K.; Raju, Y.S.N.; Venkateswarlu, K.; Murthy, K.S.R.

High-resolution shallow seismic and echo sounding profiles of the continental shelf between Visakhapatnam and Gopalpur reveal prominent morphological features like terraces, reefs and pinnacles at different water depths of 80-100 m, 50-30 m...

77 FR 29366 - Investigations Regarding Eligibility To Apply for Worker Adjustment Assistance

Science.gov (United States)

2012-05-17

... Austin, TX 04/24/12 04/23/12 Corporation (Company). 81532 Verizon Data Services, LLC Temple Terrace, FL.../25/12 Stop). 81538 State Journal Register Springfield, IL....... 04/26/12 04/25/12 (State/One-Stop...

Research Article Special Issue

African Journals Online (AJOL)

2017-02-15

Feb 15, 2017 ... Methodology is based on librarian, descriptive-analytical method that is of applied kind. Results .... this console has terraced, curved "amphitheatre"-style stop-jambs resembling those of French ... [citation needed]. In all, there ...

Tracking Geomorphic Signatures of Watershed Suburbanization with Multi-Temporal LiDAR

Science.gov (United States)

Urban development practices redistribute surface materials through filling, grading and terracing, causing drastic changes to the geomorphic organization of the landscape. Many studies document the hydrologic, biologic, or geomorphic consequences of urbanization using space-for-t...

Sustainable management of coastal saline soils in the Saloum river ...

African Journals Online (AJOL)

conductivity, pH, water soluble cations and anions) were analysed to estimate the salinity level at each .... (floodplain, low terrace), saline soils are now .... Apart from having a high salt content, ..... permeability and thereby promotes continuous.

Abbot Close Nursing Home, St. Marys Terrace, Askeaton, Limerick.

LENUS (Irish Health Repository)

Brown, Aisling F

2015-01-01

Mechanisms of protective immunity to Staphylococcus aureus infection in humans remain elusive. While the importance of cellular immunity has been shown in mice, T cell responses in humans have not been characterised. Using a murine model of recurrent S. aureus peritonitis, we demonstrated that prior exposure to S. aureus enhanced IFNγ responses upon subsequent infection, while adoptive transfer of S. aureus antigen-specific Th1 cells was protective in naïve mice. Translating these findings, we found that S. aureus antigen-specific Th1 cells were also significantly expanded during human S. aureus bloodstream infection (BSI). These Th1 cells were CD45RO+, indicative of a memory phenotype. Thus, exposure to S. aureus induces memory Th1 cells in mice and humans, identifying Th1 cells as potential S. aureus vaccine targets. Consequently, we developed a model vaccine comprising staphylococcal clumping factor A, which we demonstrate to be an effective human T cell antigen, combined with the Th1-driving adjuvant CpG. This novel Th1-inducing vaccine conferred significant protection during S. aureus infection in mice. This study notably advances our understanding of S. aureus cellular immunity, and demonstrates for the first time that a correlate of S. aureus protective immunity identified in mice may be relevant in humans.

a sedimentologic analysis of terrace sediments from the pawmpawm

African Journals Online (AJOL)

PUBLICATIONS1

Department of Geography and Rural Development, KNUST, Kumasi ... 2014 Kwame Nkrumah University of Science and Technology (KNUST) .... waterfalls, massive sedimentary channel ..... information on the degree of sorting and parti-.

Oleophobic properties of the step-and-terrace sapphire surface

Energy Technology Data Exchange (ETDEWEB)

Muslimov, A. E., E-mail: amuslimov@mail.ru; Butashin, A. V.; Kanevsky, V. M. [Russian Academy of Sciences, Shubnikov Institute of Crystallography, Federal Research Center “Crystallography and Photonics” (Russian Federation)

2017-03-15

Sapphire is widely used in production of optical windows for various devices due to its mechanical and optical properties. However, during operation the surface can be affected by fats, oils, and other organic contaminations. Therefore, it is important to improve the oleophobic properties of sapphire windows. In this study, we investigate the interaction of a supersmooth sapphire surface with oleic acid droplets, which imitate human finger printing. It is established that chemical–mechanical polishing with additional annealing in air, which leads to the formation of an atomically smooth sapphire surface, makes it possible to significantly improve the oleophobic properties of the surface. The results are analyzed using the Ventsel–Deryagin homogeneous wetting model.

Foraminifera from the deep lake terraces, Vestfold hills, Antarctica

Digital Repository Service at National Institute of Oceanography (India)

Setty, M.G.A.P.; Williams, R.; Kerry, K.R.

regarding disparity in abundance (paucity or even absence) of foraminifera in samples from identical elevations in the two transects are proposed: differential wind erosion occurred and foraminifera were deposited elsewhere; the faunas are remnants of debris...

Formation and evolution of yardangs activated by Late Pleistocene ...

Indian Academy of Sciences (India)

2School of Tourism, Hebei University of Economics and Business, Shijiazhuang 050061, China. ∗ ... Based on fieldwork, this study ascertained three levels of river terrace in the ...... Cheng J 2009 Practice book of Quaternary geology and geo-.

The Effect of Water Harvesting Techniques on Runoff, Sedimentation, and Soil Properties

Science.gov (United States)

Al-Seekh, Saleh H.; Mohammad, Ayed G.

2009-07-01

This study addressed the hydrological processes of runoff and sedimentation, soil moisture content, and properties under the effect of different water harvesting techniques (treatments). The study was conducted at three sites, representing environmental condition gradients, located in the southern part of the West Bank. For each treatment, the study evaluated soil chemical and physical properties, soil moisture at 30 cm depth, surface runoff and sedimentation at each site. Results showed that runoff is reduced by 65-85% and sedimentation by 58-69% in stone terraces and semi-circle bunds compared to the control at the semi-humid site. In addition, stone terraces and contour ridges significantly reduced the amount of total runoff by 80% and 73%, respectively, at the arid site. Soil moisture content was significantly increased by water harvesting techniques compared to the control in all treatments at the three study sites. In addition, the difference between the control and the water harvesting structures were higher in the arid and semi-arid areas than in the semi-humid area. Soil and water conservation, via utilization of water harvesting structures, is an effective principle for reducing the negative impact of high runoff intensity and subsequently increasing soil moisture storage from rainfall. Jessour systems in the valley and stone terraces were effective in increasing soil moisture storage, prolonging the growing season for natural vegetation, and decreasing the amount of supplemental irrigation required for growing fruit trees.

Time-resolved measurements of laser-induced diffusion of CO molecules on stepped Pt(111)-surfaces; Zeitaufgeloeste Untersuchung der laser-induzierten Diffusion von CO-Molekuelen auf gestuften Pt(111)-Oberflaechen

Energy Technology Data Exchange (ETDEWEB)

Lawrenz, M.

2007-10-30

In the present work the dynamics of CO-molecules on a stepped Pt(111)-surface induced by fs-laser pulses at low temperatures was studied by using laser spectroscopy. In the first part of the work, the laser-induced diffusion for the CO/Pt(111)-system could be demonstrated and modelled successfully for step diffusion. At first, the diffusion of CO-molecules from the step sites to the terrace sites on the surface was traced. The experimentally discovered energy transfer time of 500 fs for this process confirms the assumption of an electronically induced process. In the following it was explained how the experimental results were modelled. A friction coefficient which depends on the electron temperature yields a consistent model, whereas for the understanding of the fluence dependence and time-resolved measurements parallel the same set of parameters was used. Furthermore, the analysis was extended to the CO-terrace diffusion. Small coverages of CO were adsorbed to the terraces and the diffusion was detected as the temporal evolution of the occupation of the step sites acting as traps for the diffusing molecules. The additional performed two-pulse correlation measurements also indicate an electronically induced process. At the substrate temperature of 40 K the cross-correlation - where an energy transfer time of 1.8 ps was extracted - suggests also an electronically induced energy transfer mechanism. Diffusion experiments were performed for different substrate temperatures. (orig.)

The effect of water harvesting techniques on runoff, sedimentation, and soil properties.

Science.gov (United States)

Al-Seekh, Saleh H; Mohammad, Ayed G

2009-07-01

This study addressed the hydrological processes of runoff and sedimentation, soil moisture content, and properties under the effect of different water harvesting techniques (treatments). The study was conducted at three sites, representing environmental condition gradients, located in the southern part of the West Bank. For each treatment, the study evaluated soil chemical and physical properties, soil moisture at 30 cm depth, surface runoff and sedimentation at each site. Results showed that runoff is reduced by 65-85% and sedimentation by 58-69% in stone terraces and semi-circle bunds compared to the control at the semi-humid site. In addition, stone terraces and contour ridges significantly reduced the amount of total runoff by 80% and 73%, respectively, at the arid site. Soil moisture content was significantly increased by water harvesting techniques compared to the control in all treatments at the three study sites. In addition, the difference between the control and the water harvesting structures were higher in the arid and semi-arid areas than in the semi-humid area. Soil and water conservation, via utilization of water harvesting structures, is an effective principle for reducing the negative impact of high runoff intensity and subsequently increasing soil moisture storage from rainfall. Jessour systems in the valley and stone terraces were effective in increasing soil moisture storage, prolonging the growing season for natural vegetation, and decreasing the amount of supplemental irrigation required for growing fruit trees.

Sequence Stratigraphic Framework Analysis of Putaohua Oil Reservoir in Chaochang Area of Songliao Basin

Science.gov (United States)

Chang, Yan; Liu, Dameng; Yao, Yanbin

2018-01-01

The regional structure of the Changchang area in the Songliao Basin is located on the Chaoyangou terrace and Changchunling anticline belt in the central depression of the northern part of the Songliao Basin, across the two secondary tectonic units of the Chaoyanggou terrace and Changchunling anticline. However, with the continuous development of oil and gas, the unused reserves of Fuyu oil reservoir decreased year by year, and the oil field faced a serious shortage of reserve reserves. At the same time, during the evaluation process, a better oil-bearing display was found during the drilling and test oil in the Putao depression to the Chaoyanggou terraces, the Yudong-Taipingchuan area, and in the process of drilling and testing oil in the Putaohua reservoir. Zhao41, Zhao18-1, Shu38 and other exploration wells to obtain oil oil, indicating that the area has a further evaluation of the potential. Based on the principle of stratification, the Putao area was divided into three parts by using the core, logging and logging. It is concluded that the middle and western strata of the study area are well developed, including three sequences, one cycle from bottom to top (three small layers), two cycles (one small layer), three cycles (two small layers) Rhythm is positive-anti-positive. From the Midwest to the southeastern part of the strata, the strata are overtaken, the lower strata are missing, and the top rhythms become rhythmic.

Southward flow on the western flank of the Florida Current

Science.gov (United States)

Soloviev, Alexander V.; Hirons, Amy; Maingot, Christopher; Dean, Cayla W.; Dodge, Richard E.; Yankovsky, Alexander E.; Wood, Jon; Weisberg, Robert H.; Luther, Mark E.; McCreary, Julian P.

2017-07-01

A suite of long-term in situ measurements in the Straits of Florida, including the ADCP bottom moorings at an 11-m isobath and 244-m isobath (Miami Terrace) and several ADCP ship transects, have revealed a remarkable feature of the ocean circulation - southward flow on the western, coastal flank of the Florida Current. We have observed three forms of the southward flow - a seasonally varying coastal countercurrent, an undercurrent jet attached to the Florida shelf, and an intermittent undercurrent on the Miami Terrace. According to a 13-year monthly climatology obtained from the near-shore mooring, the coastal countercurrent is a persistent feature from October through January. The southward flow in the form of an undercurrent jet attached to the continental slope was observed during five ship transects from April through September but was not observed during three transects in February, March, and November. This undercurrent jet is well mixed due to strong shear at its top associated with the northward direction of the surface flow (Florida Current) and friction at the bottom. At the same time, no statistically significant seasonal cycle has been observed in the undercurrent flow on the Miami Terrace. Theoretical considerations suggest that several processes could drive the southward current, including interaction between the Florida Current and the shelf, as well as forcing that is independent of the Florida Current. The exact nature of the southward flow on the western flank of the Florida Current is, however, unknown.

Features Analysis of Dry Stone Walls of Tuscany (Italy

Directory of Open Access Journals (Sweden)

Mauro Agnoletti

2015-10-01

Full Text Available Terraced systems currently represent an indubitable added value for Tuscany, as well as for other Italian regions and for several Mediterranean countries. This value goes beyond their original function of hosting new areas for cultivation. The hydrological functions performed by these systems, including control of erosion, stabilisation of the slopes, prolongation of runoff times and the possible reduction of the volumes of surface runoff, are well-known. In addition, they also play a strategic role in the conservation of biodiversity and in maintaining local identity. At a national level, the terraced agricultural systems fall within the scope of actions scheduled in the National Strategic Plan for Rural Development 2007–2013, and the standards of Good Agricultural and Environmental Conditions (GAECs envisages that they be maintained through the granting of economic aid as laid down in the Rural Development Plans 2007–2013 and 2014–2020. Eighteen sample areas, previously selected on the basis of the terracing intensity index (defined as the ratio between the lines representing the walls and the surface of 1 ha, were subjected for on-site surveys to determine the geo-typological features through the identification and measurement of the main technical-construction parameters of the dry stone walls. This analysis also enabled assessments of the overall state of conservation of the dry stone walls in order to suggest operations for safeguarding and protection.

Vibration and noise characteristics of hook type olive harvesters

African Journals Online (AJOL)

Jane

2011-08-03

Aug 3, 2011 ... The homeland of olive upper Mesopotamia including south-eastern ... Turkey where 81% of olive trees are grown in slopped and terraced .... effectively, it has been established the minimal security level at the equivalent noise ...

Untitled

African Journals Online (AJOL)

An assessment of the sustainability of water resource development and use in the Chad Basin of .... Agriculture was based on a sophisticated system of terraces and .... OAn intermittent floodflow during the wet Season. (June to October) and ...

Adsorption of human insulin on single-crystal gold surfaces investigated by in situ scanning tunnelling microscopy and electrochemistry

DEFF Research Database (Denmark)

Welinder, Anna Christina; Zhang, Jingdong; Steensgaard, D.B.

2010-01-01

sweep, LSV, cyclic, CV, and square wave (SQWV) voltammetry. Multifarious electrochemical patterns were observed. Most attention was given to reductive desorption caused by insulin binding to the Au-surfaces via up to three disulfide groups per insulin monomer, presumably converted to single Au-S links....... SQWV suggested the Au-S bond strength order Au(111) > Au(110) > Au(100) based on the reductive desorption potentials. The voltammetric diversity was paralleled by different in situ STM insulin adsorption modes on the three surfaces. Single-molecule resolution was achieved in all cases. The coverage...... followed the order Au(110) > Au(100) > Au(111) and differs from the reductive desorption order that records the Au-S bonding element. Evenly distributed single molecules were scattered over large Au(111)-terraces, with intriguing molecular arrays disclosed near the terrace edges. In comparison, high...

Preparation of information bases on long-term stability of geological environment

International Nuclear Information System (INIS)

Umeda, Koji; Nohara, Tsuyoshi; Fujiwara, Osamu; Asamori, Koichi; Kinoshita, Hirohisa; Nakatuka, Noboru

2004-09-01

From a point of clear grasp of change of thermal and dynamic properties of rock, and flow and geochemical characteristics of groundwater, the special phenomena in Japan such as upheaval, submergence, erosion, igneous activity, seismicity and fault and change of climate and seawater were investigated. Some figures and databases are prepared by collecting information and knowledge related. They contained seven databases: active faults map of Japan, structural map of sea region in Japan and its environs, quaternary volcanoes in Japan, well temperature database, spring geochemistry database, marine terrace in Japan and distribution of landslide configuration, and four figures: geothermal gradient, marine terrace, distribution of upheaval velocity and distribution of erosion velocity in Japan. These databases and figures are explained. The characteristics of diastrophism and igneous activity in Japan are discussed from the viewpoint of long-term stability of geological environment. (S.Y.)

Controls on Late Quaternary Landscape development in the Upper Guadalentin Basin, Murcia, SE Spain

International Nuclear Information System (INIS)

Baartman, J. e. M.; Veldkamp, A.

2009-01-01

Landscapes in South-eastern Spain have developed in response to tectonics, climatic fluctuations and, more recently, to human action. In the valleys, fluvial colluvial sediments are found in the form of river terraces, pediments and slope deposits. We studied these sediments to evaluate landscape dynamics and the processes of sedimentation and erosion in the semi-arid region of the Guadalentin Basin, Murcia Province, SE Spain. The objective of the study is to deduce controls on Late Quaternary and Holocene landscape development. Fieldwork was carried out on the reach of the Upper Guadalentin, upstream of the city of Lorca, and two of its tributaries (Rio Velez and Rambla de Torrealvilla). River terrace levels were mapped using GPS and presence of gravel layers in outcrops. For the Rambla de Torrealvilla, more detailed sediment descriptions show their build-up. (Author) 18 refs.

True atomic-scale imaging of a spinel Li{sub 4}Ti{sub 5}O{sub 12}(111) surface in aqueous solution by frequency-modulation atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Kitta, Mitsunori, E-mail: m-kitta@aist.go.jp; Kohyama, Masanori [Research Institute for Ubiquitous Energy Devices, National Institute of Advanced Industrial Science and Technology, 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Onishi, Hiroshi [Department of Chemistry, Graduate School of Science, Kobe University 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan)

2014-09-15

Spinel-type lithium titanium oxide (LTO; Li{sub 4}Ti{sub 5}O{sub 12}) is a negative electrode material for lithium-ion batteries. Revealing the atomic-scale surface structure of LTO in liquid is highly necessary to investigate its surface properties in practical environments. Here, we reveal an atomic-scale image of the LTO(111) surface in LiCl aqueous solution using frequency-modulation atomic force microscopy. Atomically flat terraces and single steps having heights of multiples of 0.5 nm were observed in the aqueous solution. Hexagonal bright spots separated by 0.6 nm were also observed on the flat terrace part, corresponding to the atomistic contrast observed in the ultrahigh vacuum condition, which suggests that the basic atomic structure of the LTO(111) surface is retained without dramatic reconstruction even in the aqueous solution.

Potential application of remote sensing in monitoring informal settlements in developing countries where complimentary data does not exist

CSIR Research Space (South Africa)

Busgeeth, K

2008-04-01

Full Text Available Middle Class : Retreat Upper Middle Class : Terracotta Terraces Upper Middle Class : Dish and Decoder Set Upper Middle Class : Suburban Bliss Silver Spoons: Big Fish Silver Spoons: Fashion Cafe Society Silver Spoons: Cheese and Wine Silver Spoons...

Browse Title Index

African Journals Online (AJOL)

Items 1 - 44 of 44 ... Vol 28, No 1 (2006), Determinants of small farm household food security: ... Vol 26, No 2 (2004), Environment-induced migration, violent conflict and ... effects of tourism in Konso Terrace and cultural landscape, Ethiopia: ...

7 CFR 1781.6 - Loan purposes.

Science.gov (United States)

2010-01-01

... conservation and water control facilities such as dikes, terraces, detention reservoirs, stream channels... vegetative measures to stabilize stream channels and gullies. (iv) Basic farm conservation practices to control runoff, erosion, and sedimentation. (6) Installing, repairing, and improving water storage...

Imprints of Chilika Lake in the offshore region – A geomorphologic evidence

Digital Repository Service at National Institute of Oceanography (India)

Subrahmanyam, V.; Murthy, K.S.R.; Subrahmanyam, A.S.; Rao, K.M.; Sarma, K.V.L.N.S.; Reddy, N.P.C; Murty, G.P.S.; Devi, D.K.

of Oceanography, Visakhapatnam, Andhra Pradesh, India. The bathymetry profiles along the survey traverses show several channels with varied dimensions in the slope region of the seafloor. Step like terraces in the slope region followed by a V shaped channel of 400...

SiO2/TiO2 multi-layered thin films with self-cleaning and enhanced ...

Indian Academy of Sciences (India)

473–482. © Indian Academy of Sciences ... along with a similar decrease in the CO2 emissions in order to ... used for domestic hot-water preparation, installed on roofs, terraces .... assumption of larger internal stress induced by these possible.

Idaho Batholith Study Area Density Grid

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A 2 kilometer terrace-density grid for the Idaho batholith study area. Number of columns is 331 and number of rows is 285. The order of the data is from the lower...

76 FR 24499 - National Eye Institute; Notice of Closed Meeting

Science.gov (United States)

2011-05-02

... the public as indicated below, with attendance limited to space available. Individuals who plan to... disclose confidential trade secrets or commercial property such as patentable material, and personal... discussions concerning Institute programs. Place: National Institutes of Health, 5635 Fishers Lane, Terrace...

77 FR 31032 - National Eye Institute; Notice of Closed Meeting

Science.gov (United States)

2012-05-24

... the public as indicated below, with attendance limited to space available. Individuals who plan to... disclose confidential trade secrets or commercial property such as patentable material, and personal... concerning Institute programs. Place: National Institutes of Health, 5635 Fishers Lane, Terrace Level...

77 FR 73037 - National Eye Institute; Notice of Closed Meeting

Science.gov (United States)

2012-12-07

... the public as indicated below, with attendance limited to space available. Individuals who plan to... disclose confidential trade secrets or commercial property such as patentable material, and personal... discussions concerning Institute programs. Place: National Institutes of Health, 5635 Fishers Lane, Terrace...

77 FR 55852 - National Eye Institute; Notice of Closed Meeting

Science.gov (United States)

2012-09-11

... the public as indicated below, with attendance limited to space available. Individuals who plan to... disclose confidential trade secrets or commercial property such as patentable material, and personal... concerning Institute programs. Place: National Institutes of Health, 5635 Fishers Lane, Terrace Level...

75 FR 76474 - National Eye Institute; Notice of Closed Meeting

Science.gov (United States)

2010-12-08

... the public as indicated below, with attendance limited to space available. Individuals who plan to... disclose confidential trade secrets or commercial property such as patentable material, and personal... concerning Institute programs. Place: National Institutes of Health, 5635 Fishers Lane, Terrace Level...

76 FR 53687 - National Eye Institute Notice of Closed Meeting

Science.gov (United States)

2011-08-29

... the public as indicated below, with attendance limited to space available. Individuals who plan to... disclose confidential trade secrets or commercial property such as patentable material, and personal... concerning Institute programs. Place: National Institutes of Health, 5635 Fishers Lane, Terrace Level...

77 FR 2076 - National Eye Institute; Notice of Closed Meeting

Science.gov (United States)

2012-01-13

... the public as indicated below, with attendance limited to space available. Individuals who plan to... disclose confidential trade secrets or commercial property such as patentable material, and personal... concerning Institute programs. Place: National Institutes of Health, 5635 Fishers Lane, Terrace Level...

Agriculture development and food security policy in Eritrea - An ...

African Journals Online (AJOL)

Agriculture development and food security policy in Eritrea - An analysis. ... per cent of its total food needs and in poor years, it produces no more than 25 per cent. ... food security by introducing modern technology, irrigation, terracing, soil and ...

Land use change impacts on floods at the catchment scale

NARCIS (Netherlands)

Rogger, M.; Agnoletti, M.; Alaoui, A.; Bathurst, J.C.; Bodner, G.; Borga, M.; Chaplot, Vincent; Gallart, F.; Glatzel, G.; Hall, J.; Holden, J.; Holko, L.; Horn, R.; Kiss, A.; Kohnová, S.; Leitinger, G.; Lennartz, B.; Parajka, J.; Perdigão, R.; Peth, S.; Plavcová, L.; Quinton, John N.; Robinson, Matthew R.; Salinas, J.L.; Santoro, A.; Szolgay, J.; Tron, S.; Akker, van den J.J.H.; Viglione, A.; Blöschl, G.

2017-01-01

Research gaps in understanding flood changes at the catchment scale caused by changes in forest management, agricultural practices, artificial drainage, and terracing are identified. Potential strategies in addressing these gaps are proposed, such as complex systems approaches to link processes

Influence of growth parameters on the surface morphology and ...

Indian Academy of Sciences (India)

Unknown

surface features of the grown film like terracing, inclusions, meniscus lines, etc are ... Recently, studies carried out on the growth of InSb ..... is a critical factor in any epitaxial growth process and can ... However, this approach can lead to.

Conductivity of epitaxial and CVD graphene with correlated line defects

DEFF Research Database (Denmark)

Radchenko, T. M.; Shylau, Artsem; Zozoulenko, I. V.

2014-01-01

Transport properties of single-layer graphene with correlated one-dimensional defects are studied theoretically using the computational model within the time-dependent real-space Kubo-Greenwood formalism. Such defects are present in epitaxial graphene, comprising atomic terraces and steps due...

profitability of soil erosion control technologies in eastern uganda

African Journals Online (AJOL)

Prof. Adipala Ekwamu

The lack of farmer awareness of costs and benefits associated with the use of ... example, the profits expected from the use of terraces and trees would reduce by about 3 percent if inflation rose ..... CIMMYT Economic working paper 03-07.

THE LATE QUATERNARY TECTONO-STRATIGRAPHIC EVOLUTION OF THE LAKE VAN, TURKEY

Directory of Open Access Journals (Sweden)

Naci GÖRÜR

2015-12-01

Full Text Available Many of the terraces around the Lake Van record a relatively short period of the much lon- ger geological history of the Lake Van Basin. Their deposition took place during the last ca. 125 ka BP. They accumulated in a large array of shallow lake and lake margin environments, such as alluvial fan/braided river, beach, Gilbert-type delta, nearshore lake and offshore la- ke. Variability of their lithofacies provides evidence for climatic and tectonic controls of the- ir depositional conditions. During their deposition high relief areas in the watershed delive- red abundant detritus to the coastal areas of the lake. The sedimentation was therefore domi- nated by terrigenous clastic deposits. The highest concentrations  of the coarse clastic sedi- ments were at the mouths of the major streams where they formed Gilbert-type deltas. The- se river-dominated lacustrine deltas formed during rising lake levels and are relatively more abundant and thicker in the eastern margin of the lake, indicating that this margin mostly had a low-energy coast sheltered from the prevailing westerly winds. However, some areas of the same margin adjacent to deltas were also supplied with sediments by waves and storm-indu- ced longshore currents to form beaches. Storms and storm-generated  traction currents were perhaps active agents along the shores of the Lake Paleo-Van as suggested by the presence of the coarse-grained material in its nearshore facies. Somehow, during times of lake high- stands, turbidity currents seem not to have played an important role in the sediment transpor- tation along the lake margin, because the nearshore sediments hardly show any evidence of turbidite depositon, such as graded bedding and sole-marks. The offshore lake was relatively quite standing water, depositing laterally persistent, thinly-bedded to varved and fine-grained sandstones and mudstones in part with hydroplastic disruptions, such as slumps and convo- lute beddings. Because of

The traditional irrigation technique of Lake Garda lemon--houses (Northern Italy)

Science.gov (United States)

Barontini, Stefano; Vitale, Nicola; Fausti, Federico; Bettoni, Barbara; Bonati, Sara; Peli, Marco; Pietta, Antonella; Tononi, Marco; Ranzi, Roberto

2016-04-01

Between 16th and 19th centuries the North-Western side of Lake Garda was seat of an important district which, at the time of its maximum splendour between 18th and 19th centuries, produced and exported lemons and citrus even toward the Northern Europe and the Russia. The limonaie del Garda (Lake-Garda lemon-houses), the local name of the citrus orchards, were settled on terraces built on steep slopes, with landfill taken from the Eastern side of the lake, and closed by greenhouses during late autumn and winter in order to protect the cultivations. The terraces were built nearby streams, they were South-Eastern exposed and protected by walls from the cold winds. Thanks in fact to the Lake Garda microclimate, lemon trees were not cultivated in pots, as in the typical orangeries of mid-latitudes Europe, but directly in the soil. Here the citrus cultivation technique reached a remarkably high degree of standardisation, with local cultivar as the Madernino or lemon from Maderno, and it involved, as in modern industrial districts, all the surrounding land in order to satisfy the needing of required materials to build the terraces, the walls, the greenhouses and the wooden frames to hold the branches laden with fruits. Due to the great water requirement of lemon trees during summer, which is estimated to range from 150 to 300 ℓ every ten days, the water management played a key role in the cultivation technique. The traditional irrigation technique was standardized as well. During our surveys, we observed that most of the lemon-houses still conserve little stone flumes along the walls upslope to the terraces, with spillways every adult tree, i.e. about every 4 m. The flumes were filled with water taken from an upstream reservoir, built nearby a stream. The spillways were activated with a backwater obtained by means of a sand bag placed within the flume, just downstream to the spillway itself. In order to avoid any excavation, spilled water was driven to the base of each

Soil Organic Carbon Stocks in Arctic Deltaic Sediments: Investigations in the Lena River Delta.

Science.gov (United States)

Zubrzycki, S.; Kutzbach, L.; Desyatkin, A.; Pfeiffer, E.-M.

2012-04-01

The soil organic carbon stock (SSOC) of deltaic sediments in arctic permafrost regions is known to be significant but is insufficiently investigated so far. Previous SSOC studies were conducted mainly in the comparatively well studied Mackenzie River Delta (area: 13,000 km2) in Canada. The few studies from other arctic delta regions report only the gravimetric carbon (C) contents and are limited to the active layer depth at the time of sampling. Since C deposits in permafrost regions are likely to become a future C source, more detailed investigations of the presently frozen likely carbon-rich sediment and soil layers in other arctic delta regions are of importance. Our investigations were performed on Samoylov Island in the southern-central part of the Lena River Delta (32,000 km2) which is the largest arctic delta and the fifth largest delta worldwide. Samoylov Island is representative for the Lena River Delta's first terrace and the active floodplains. Within this study a new portable Snow-Ice-Permafrost-Research-Establishment (SIPRE) auger was used during a spring field session to obtain 1 m deep frozen soil cores (n = 37) distributed over all known soil and vegetation units. These cores are analyzed for bulk contents of nitrogen (N) and C, ice content and bulk density (BD) and to determine the SSOC including the rarely investigated currently permanently frozen layers up to 1 m depth on Samoylov Island. Our study provides evidence for high SSOC for a depth of 1 m for the investigated area ranging between 6 kg m2 and 54 kg m2. Considering the spatial extent of different soil units on the two geomorphological units of Samoylov Island, the area-weighted average SSOC were 31 kg m2 (n = 31) for the first terrace and 15 kg m2 (n = 6) for the active floodplain. For the correspondent soil units of Turbels and Orthels in circumpolar permafrost regions, Tarnocai et al. 2009 reported a mean SSOC of 27 kg m2 (min: 0.1 kg m2, max: 126 kg m2) for a depth of 1 m. For up

Geomorphic Evidence of Coseismic Coastline Changes in Southern Miura Peninsula Associated with the Recent Kanto Earthquakes: Analysis of the LIDAR Data, air Photos and Topo Maps

Science.gov (United States)

Kim, H.; Kumaki, Y.; Satake, K.

2011-12-01

In order to study geomorphic evidence related to the past Kanto earthquakes, we analyzed LIDAR data, air photos and topographical maps, and traced uplifted marine terraces during the recent earthquakes including the 1923 and 1703 earthquakes. Tokyo Metropolitan Area's well-documented earthquake history is dominated by the 1703 and 1923 great Kanto earthquakes, that were resulted from the subducting Philippine Sea plate. Around the source region of the past Kanto earthquakes, Miura and Boso Peninsulas are located facing the Sagami Bay. The average recurrence interval of Kanto earthquake has been estimated on basis of the seismological, geodetic, geological and gemorophological data. The Earthquake Research Committee [2004] proposed that there are types of earthquakes with the recurrence intervals of 200-400 years, and about 2300 years. They produced different amounts of uplift at Boso Peninsula, but the uplifts of Miura Peninsula are similar. The uplift amounts of Miura Peninsula have been estimated about 1.5 m in 1923 and 1703, from the wave-cut-benches, -notches and the distribution of fossil remains along the coast [Matsuda et al. (1978), Shishikura et al. (2007)]. The coastline just before the 1923 earthquakes can be restored from the old topographical map. By using it, the coseismic uplifts associated with the 1923 and 1703 earthquakes may be more accurately estimated. The air photos we used are by 1946 U.S. forces photography and 1963/1966 Geographical Survey Institute photography; the topographical maps are 1:25,000 topographical maps measured in 1921 and 1:20,000 topographical maps of the Meiji period. In addition, we made a high-density (50 cm mesh) digital elevations map by aerial measurements of the Light Detection and Ranging (LIDAR). In Miura Peninsula, three additional steps of marine terrace surface are formed at 7 to 20 m above MSL, at ~5200,~3300 and ~1500 cal. BC, and these are called Nobi 1, 2 and 3 in order from top [Kumaki, 1985; 14C Age was

The Impact of Urbanization on the Regional Aeolian Dynamics of an Arid Coastal Dunefield

Science.gov (United States)

Smith, Alexander; Jackson, Derek; Cooper, Andrew

2016-04-01

The anthropogenic impact on the geomorphology of many landscapes are inextricably connected but are often neglected due to the difficulty in making a direct link between the quasi natural and human processes that impact the environment. This research focuses on the Maspalomas dunefield, located on the southern coast of Gran Canaria, in the Canary Island Archipelago. The tourism industry in Maspalomas has led to intensive urbanization since the early 1960's over an elevated alluvial terrace that extends into the dunefield. Urbanization has had a substantial impact on both the regional airflow conditions and the geomorphological development of this transverse dune system. As a result airflow and sediment has been redirected in response to the large scale construction efforts. In situ data was collected during field campaigns using high resolution three-dimensional anemometry to identify the various modifications within the dunefield relative to incipient regional airflow conditions. The goal is to analyse the flow conditions near the urbanized terrace in relation to areas that are located away from the influence of the buildings and to verify numerical modelling results. Computational Fluid Dynamics (CFD) modelling is used in order to expand the areal extent of analysis by providing an understanding of relevant flow dynamics (e.g. flow velocity, directionality, turbulence, shear stresses, etc.) at the mesoscale. An integrative three dimensional model for CFD simulations was created to address the impact of both the urban area (i.e. hotels, commercial centers, and residential communities) as well as the dune terrain on regional flow conditions. Early modelling results show that there is significant flow modification around the urban terrace with streamline compression, acceleration, and deflection of flow on the windward side of the development. Consequently downwind of the terrace there is an area of highly turbulent flow conditions and well developed separation and

Scanning tuneeling microscopy studies of fivefold surfaces of icosahedral Al-Pd-Mn quasicrystals and of thin silver films on those surfaces

Energy Technology Data Exchange (ETDEWEB)

Unal, Baris [Iowa State Univ., Ames, IA (United States)

2008-01-01

The present work in this dissertation mainly focuses on the clean fivefold surfaces of i-Al-Pd-Mn quasicrystals as well as the nucleation and growth of Ag films on these surfaces. In addition, Ag film growth on NiAl(110) has been explored in the frame of this dissertation. First, we have investigated the equilibration of a fivefold surface of icosahedral Al-Pd-Mn quasicrystal at 900-915 K and 925-950 K, using Omicron variable temperature scanning tunneling microscope (STM). Annealing at low temperatures resulted in many voids on some terraces while the others were almost void-free. After annealing at 925-950K, void-rich terraces became much rarer. Our STM images suggest that through growth and coalescence of the voids, a different termination becomes exposed on host terraces. All of these observations in our study indicate that even after the quasicrystalline terrace-step structure appears, it evolves with time and temperature. More specifically, based on the STM observations, we conclude that during the annealing a wide range of energetically similar layers nucleate as surface terminations, however, with increasing temperature (and time) this distribution gets narrower via elimination of the metastable void-rich terraces. Next, we have examined the bulk structural models of icosahedral Al-Pd-Mn quasicrystal in terms of the densities, compositions and interplanar spacings for the fivefold planes that might represent physical surface terminations. In our analyses, we mainly have focused on four deterministic models which have no partial or mixed occupancy but we have made some comparisons with an undeterministic model. We have compared the models with each other and also with the available experimental data including STM, LEED-IV, XPD and LEIS. In all deterministic models, there are two different families of layers (a pair of planes), and the nondeterministic model contains similar group of planes. These two families differ in terms of the chemical decoration of

Neotectonics and structure of the Himalayan deformation front in the Kashmir Himalaya, India: Implication in defining what controls a blind thrust front in an active fold-thrust belt

Science.gov (United States)

Gavillot, Y. G.; Meigs, A.; Yule, J. D.; Rittenour, T. M.; Malik, M. O. A.

2014-12-01

Active tectonics of a deformation front constrains the kinematic evolution and structural interaction between the fold-thrust belt and most-recently accreted foreland basin. In Kashmir, the Himalayan Frontal thrust (HFT) is blind, characterized by a broad fold, the Suruin-Mastargh anticline (SMA), and displays no emergent faults cutting either limb. A lack of knowledge of the rate of shortening and structural framework of the SMA hampers quantifying the earthquake potential for the deformation front. Our study utilized the geomorphic expression of dated deformed terraces on the Ujh River in Kashmir. Six terraces are recognized, and three yield OSL ages of 53 ka, 33 ka, and 0.4 ka. Vector fold restoration of long terrace profiles indicates a deformation pattern characterized by regional uplift across the anticlinal axis and back-limb, and by fold limb rotation on the forelimb. Differential uplift across the fold trace suggests localized deformation. Dip data and stratigraphic thicknesses suggest that a duplex structure is emplaced at depth along the basal décollement, folding the overlying roof thrust and Siwalik-Muree strata into a detachment-like fold. Localized faulting at the fold axis explains the asymmetrical fold geometry. Folding of the oldest dated terrace, suggest that rock uplift rates across the SMA range between 2.0-1.8 mm/yr. Assuming a 25° dipping ramp for the blind structure on the basis of dip data constraints, the shortening rate across the SMA ranges between 4.4-3.8 mm/yr since ~53 ka. Of that rate, ~1 mm/yr is likely absorbed by minor faulting in the near field of the fold axis. Given that Himalaya-India convergence is ~18.8-11 mm/yr, internal faults north of the deformation front, such as the Riasi thrust absorbs more of the Himalayan shortening than does the HFT in Kashmir. We attribute a non-emergent thrust at the deformation front to reflect deformation controlled by pre-existing basin architecture in Kashmir, in which the thick succession

Evidence of soil nutrient availability as the proximate constraint on growth of treeline trees in northwest Alaska.

Science.gov (United States)

Sullivan, Patrick F; Ellison, Sarah B Z; McNown, Robert W; Brownlee, Annalis H; Sveinbjörnsson, Bjartmar

2015-03-01

The position of the Arctic treeline, which is a key regulator of surface energy exchange and carbon cycling, is widely thought to be controlled by temperature. Here, we present evidence that soil nutrient availability, rather than temperature, may be the proximate control on growth of treeline trees at our study site in northwest Alaska. We examined constraints on growth and allocation of white spruce in three contrasting habitats. The habitats had similar aboveground climates, but soil temperature declined from the riverside terrace to the forest to the treeline. We identified six lines of evidence that conflict with the hypothesis of direct temperature control and/or point to the importance of soil nutrient availability. First, the magnitude of aboveground growth declined from the terrace to the forest to the treeline, along gradients of diminishing soil nitrogen (N) availability and needle N concentration. Second, peak rates of branch extension, main stem radial and fine-root growth were generally not coincident with seasonal air and soil temperature maxima. At the treeline, in particular, rates of aboveground and fine-root growth declined well before air and soil temperatures reached their seasonal peaks. Third, in contrast with the hypothesis of temperature-limited growth, growing season average net photosynthesis was positively related to the sum of normalized branch extension, main stem radial and fine-root growth across trees and sites. Fourth, needle nonstructural carbohydrate concentration was significantly higher on the terrace, where growth was greatest. Fifth, annual branch extension growth was positively related to snow depth, consistent with the hypothesis that deeper snow promotes microbial activity and greater soil nutrient availability. Finally, the tree ring record revealed a large growth increase during late 20th-century climate warming on the terrace, where soil N availability is relatively high. Meanwhile, trees in the forest and at the

Calcium carbonate precipitation in the Cueva di Watapana on Bonaire, Netherlands Antilles

NARCIS (Netherlands)

Meer Mohr, van der C.G.

1978-01-01

Calcium carbonate precipitates as low Mg-calcite and aragonite in slightly brackish water in a cave in the Pleistocene Middle Terrace of southern Bonaire. The calcium carbonate precipitates at the atmosphere-water interface forming floating calcite scales (calcite ice). Aragonite crystals frequently

75 FR 6398 - Ocean Transportation Intermediary License Applicants

Science.gov (United States)

2010-02-09

... Forwarder Transportation Intermediary Applicants Best Way Logistics Corp., 901 SW. 98th Terrace, Pembroke..., Officers, Alessandro E. Bernardini, Sales Manager, (Qualifying Individual), Glenda Valdez, President... Intermediary Applicants (Cont'd): Vortex Worldwide Logistics Corp., 10125 NW. 116th Way, 10, Miami, FL 33178...

Unravelling Late Pleistocene and Holocene landscape dynamics: The Upper Guadalentín Basin, SE Spain 9

NARCIS (Netherlands)

Baartman, J.E.M.; Veldkamp, A.; Schoorl, J.M.; Wallinga, J.; Cammeraat, L.H.

2011-01-01

Landscapes in SE Spain have developed in response to tectonics, climate fluctuations and, more recently, human activity. Fluvial and colluvial sediments such as river terraces and slope deposits found in the valleys reflect a complex interplay between landscape forming processes. Investigating these

Unravelling Late Pleistocene and Holocene landscape dynamics: The Upper Guadalentín Basin, SE Spain

NARCIS (Netherlands)

Baartman, J.E.M.; Veldkamp, A.; Schoorl, J.M.; Wallinga, J.; Cammeraat, L.H.

2011-01-01

Landscapes in SE Spain have developed in response to tectonics, climate fluctuations and, more recently, human activity. Fluvial and colluvial sediments such as river terraces and slope deposits found in the valleys reflect a complex interplay between landscape forming processes. Investigating these

Sedimenty terciéru a kvartéru a geomorfologický vývoj na Křivoklátsku

Czech Academy of Sciences Publication Activity Database

Ložek, Vojen; Žák, Karel

2011-01-01

Roč. 31, - (2011), s. 49-94 ISSN 0231-5807 Institutional research plan: CEZ:AV0Z30130516 Keywords : Křivoklát area * geomorphology * Tertiary fluvial sediments * Quaternary river terraces * loess * slope sediments * Holocene calcareous tufa Subject RIV: DB - Geology ; Mineralogy

What we do | Page 37 | IDRC - International Development Research ...

International Development Research Centre (IDRC) Digital Library (Canada)

Results 361 - 370 of 2018 ... We collaborate with governments, research institutions, and global funders to develop solutions to multiply our impact. .... Understanding the Effect of Skills Training on Women's Economic Opportunities in Pakistan ... Developing innovative sustainable agricultural kits for Nepalese terrace farmers.

Influence of natural and anthropogenic factors on the distribution of xerothermic plants in the lower San river valley (SE Poland

Directory of Open Access Journals (Sweden)

Rafał Krawczyk

2012-12-01

Full Text Available The aim of the present study was to describe the distribution of xerothermic species of vascular plants in the lower San River valley and the relationship between their density and the intensity of selected environmental (natural and anthropogenic factors. Xerothermic species occurred more frequently in the present valley floor compared to the glacial terrace. Within the present valley, the highest density was observed in the floodplain. The examined species also occurred more often on steep slopes of the valley, at the margins of the present valley terraces, and in the area of occurrence of aeolian sands. Moreover, a positive correlation has been found between the number of xerothermic species and the area of polyhemeroby ecosystems. The distribution of xero- and thermophilous species is determined by natural edaphic and geomorphological factors as well as anthropogenic ones (land use, lowering of the groundwater level as a result of river regulation.

Parent-martensite interface structure in ferrous systems

International Nuclear Information System (INIS)

Ma, X.; Pond, R.C.

2007-01-01

Recently, a Topological Model of martensitic transformations has been presented wherein the habit plane is a semi-coherent structure, and the transformation mechanism is shown explicitly to be diffusionless. This approach is used here to model martensitic transformations in ferrous alloys. The habit plane comprises coherent (1 1 1) γ parallel (0 1 1) α terraces where the coherency strains are accommodated by a network of dislocations, originating in the martensite phase, and disconnections (transformation dislocations). The disconnections can move conservatively across the interface, thereby effecting the transformation. Since the disconnections exhibit step character, the overall habit plane deviates from the terrace plane. A range of network geometries is predicted corresponding to orientation relationships varying from Nishiyama-Wasserman to Kurdjumov-Sachs. This range of solutions includes habit planes close to {2 9 5}, {5 7 5} and {1 2 1}, in good agreement with experimental observations in various ferrous alloys

Natural recovery of different areas of a deserted quarry in South China

Institute of Scientific and Technical Information of China (English)

DUAN Wenjun; REN Hai; FU Shenglei; WANG Jun; YANG Long; ZHANG Jinping

2008-01-01

A quarry is a surface mining operated place, which produces enormous quantities of gravel, limestone, and other materials for industrial and construction applications. Restoration and revegetation of deserted quarries are becoming increasingly important. Three areas of a typical quarry in South China: terrace for crushed materials (terrace), spoiled mound, and remaining side slope, were investigated, to compare the existing plant species and to study the relationship between environmental factors and revegetation. The plant species composition of these three areas was found to differ significantly after eight years of natural recovery. The typical plant communities found over them were composed of gramineous herbs, fems, and shrubs. Soil organic matter, soil moisture, and soil bulk density were considered to be the major determining factors for vegetation succession. There existed abiotic and biotic thresholds during quarrying restoration. Suggestions had been presented that could have accelerated the process of natural recovery in quarries.

Vertical motion of the lithosphere - From the erosion of rocky coastlines to geo-dynamics via dating with Beryllium-10

International Nuclear Information System (INIS)

Regard, V.

2010-01-01

This thesis for the 'accreditation to conduct researches' diploma consists of four chapters: 1) the geo-dynamics of subduction zones, 2) the geo-morphology of rocky coastlines, 3) Be 10 - dating and methodology, and 4) the formation of marine or river terraces. The Be 10 dating method is based on the production of Be 10 in the soil by the neutrons forming the most part of the cosmic ray cascade when this cascade reaches the earth surface. By measuring the concentration of Be 10 in a soil sample and according to some assumptions, we can deduce how long a particular surface has been exposed. This method is used here to determine when a particular deposit was made and as a consequence to determine the long-term time evolution of the withdrawal of a cliff by dating samples taken on the terrace at the base of the cliff. (A.C.)

Laminae development in opal-A precipitates associated with seasonal growth of the form-genus Calothrix (Cyanobacteria), Rehai geothermal area, Tengchong, Yunnan Province, China

Science.gov (United States)

Jones, Brian; Peng, Xiaotong

2015-04-01

The western discharge apron at Meinuquan (Rehai geothermal area, Yunnan Province, China), which incorporates the upper terrace, terrace front, and lower terrace, is covered with laminated opal-A precipitates that have formed from the spring waters that flow across its surface. Laminae are formed of silicified Calothrix mats or featureless opal-A that contains no microbes, scattered spherical and rod-shaped microbes, and/or rare Calothrix. Rapid silicification of the Calothrix led to preservation of their basal heterocysts, vegetative cells, trichomes, tapering filaments, and laminated and splayed sheaths. The Calothrix mats grew during the dry season when there was maximum sunlight because of low cloud cover. During this time, the mats grew under stable conditions because the water that flowed across the discharge apron was sourced from the springs, and temperature and water geochemistry was more or less constant. Growth of the Calothrix mats decreased during the wet season (April to late September) when sunlight is reduced due to the extensive cloud cover associated with the monsoonal rains. During the wet season, water flowing over the discharge apron is a mixture of rainwater, runoff from the surrounding hillsides, and spring water. Such variable flow conditions, water temperatures, and water geochemistry curtailed microbe growth and impacted silica precipitation. The precipitates at Meinuquan are like those associated with some Icelandic hot springs. Although growth of Calothrix is controlled by sunlight in both settings, the periods of maximum sunlight in China (October-March) and Iceland (June-August) are at different times of the year because of their geographic locations.

Building damage concentrated in Longtoushan town during the 2014 Ms. 6.5 Ludian earthquake, Yunnan, China: examination of cause and implications based on ground motion and vulnerability analyses

Science.gov (United States)

Wang, Xin; Kurahashi, Susumu; Wu, Hao; Si, Hongjun; Ma, Qiang; Dang, Ji; Tao, Dongwang; Feng, Jiwei; Irikura, Kojiro

2017-09-01

Though the 2014 Ludian Earthquake had only a moderate magnitude (Ms 6.5), high-level ground motions of almost 1 g occurred at Longtoushan Town (seismic station 53LLT), which located near the intersection of a conjugate-shaped seismogenic fault. The building damages on the pluvial fan and the river terrace at Longtoushan was clearly different. In order to examine the generation of the large acceleration at 53LLT, the focal mechanisms and the rupture processes of the conjugate-shaped seismogenic fault were determined. We found that there were two continuous impulsive waves in the records of 53LLT that were generated from two different faults, the Baogunao fault and the Xiaohe fault, respectively. Site effects on the pluvial fan and the river terrace at Longtoushan Town and their relations to different building damages were examined. We found that the predominant period at the pluvial fan was about 0.25 s, close to the fundamental natural period of multi-story confined masonry buildings. Ground motions on the pluvial fan and the river terrace were simulated through convolving synthesized bedrock motions with the transfer functions, which were analyzed using the one-dimensional underground velocity structures identified from H/V spectral ratios of ambient noise. Building collapse ratios (CRs) are estimated based on the vulnerability function of the 2008 Wenchuan Earthquake and are compared with the observed values. We found that the observed building CRs on the pluvial fan are much higher than the estimated values. High-level ground shaking that is far beyond the design level was a reason for serious building damage.

Habitat use and movement of the endangered Arroyo Toad (Anaxyrus californicus) in coastal southern California

Science.gov (United States)

Gallegos, Elizabeth; Lyren, Lisa M.; Lovich, Robert E.; Mitrovich, Milan J.; Fisher, Robert N.

2011-01-01

Information on the habitat use and movement patterns of Arroyo Toads (Anaxyrus californicus) is limited. The temporal and spatial characteristics of terrestrial habitat use, especially as it relates to upland use in coastal areas of the species' range, are poorly understood. We present analyses of radiotelemetry data from 40 individual adult toads tracked at a single site in coastal southern California from March through November of 2004. We quantify adult Arroyo Toad habitat use and movements and interpret results in the context of their life history. We show concentrated activity by both male and female toads along stream terraces during and after breeding, and, although our fall sample size is low, the continued presence of adult toads in the floodplain through the late fall. Adult toads used open sandy flats with sparse vegetation. Home-range size and movement frequency varied as a function of body mass. Observed spatial patterns of movement and habitat use both during and outside of the breeding period as well as available climatological data suggest that overwintering of toads in floodplain habitats of near-coastal areas of southern California may be more common than previously considered. If adult toads are not migrating out of the floodplain at the close of the breeding season but instead overwinter on stream terraces in near-coastal areas, then current management practices that assume toad absence from floodplain habitats may be leaving adult toads over-wintering on stream terraces vulnerable to human disturbance during a time of year when Arroyo Toad mortality is potentially highest.

Contingency table analysis of pebble lithology and roundness: A case study of Huangshui River, China and comparison to rivers in the Rocky Mountains, USA

Science.gov (United States)

Miao, X.; Lindsey, D.A.; Lai, Z.; Liu, Xiuying

2010-01-01

Contingency table analysis of pebble lithology and roundness is an effective way to identify the source terrane of a drainage basin and to distinguish changes in basin size, piracy, tectonism, and other events. First, the analysis to terrace gravel deposited by the Huangshui River, northeastern Tibet Plateau, China, shows statistically contrasting pebble populations for the oldest terrace (T7, Dadongling, 1.2. Ma) and the youngest terraces (T0-T3, ?. 0.15. Ma). Two fluvial processes are considered to explain the contrast in correlation between lithology and roundness in T7 gravel versus T0-T3 gravel: 1) reworking of T7 gravel into T0-T3 gravel and 2) growth in the size of the river basin between T7 and T0-T3 times. We favor growth in basin size as the dominant process, from comparison of pebble counts and contingency tables. Second, comparison of results from Huangshui River of China to three piedmont streams of the Rocky Mountains, USA highlights major differences in source terrane and history. Like Rocky Mountain piedmont gravel from Colorado examples, the Huangshui gravels show a preference (observed versus expected frequency) for rounded granite. But unlike Rocky Mountain gravel, Huangshui gravel shows a preference for angular quartzite and for rounded sandstone. In conclusion, contrasting behavior of lithologies during transport, not always apparent in raw pebble counts, is readily analyzed using contingency tables to identify the provenance of individual lithologies, including recycled clasts. Results of the analysis may help unravel river history, including changes in basin size and lithology. ?? 2009.

Neogene-Quaternary slow coastal uplift of Western Europe through the perspective of sequences of strandlines from the Cotentin Peninsula (Normandy, France)

Science.gov (United States)

Pedoja, K.; Jara-Muñoz, J.; De Gelder, G.; Robertson, J.; Meschis, M.; Fernandez-Blanco, D.; Nexer, M.; Poprawski, Y.; Dugué, O.; Delcaillau, B.; Bessin, P.; Benabdelouahed, M.; Authemayou, C.; Husson, L.; Regard, V.; Menier, D.; Pinel, B.

2018-02-01

The Cotentin Peninsula (Normandy, France) displays sequences of marine terraces and rasas, the latter being wide Late Cenozoic coastal erosion surfaces, that are typical of Western European coasts in Portugal, Spain, France and southern England. Remote sensing imagery and field mapping enabled reappraisal of the Cotentin coastal sequences. From bottom to top, the N Cotentin sequence includes four previously recognized Pleistocene marine terraces (T1 to T4) at elevations 5e), sequential morphostratigraphy and modelling, we have reappraised uplift rates and derived: (i) mean Upper Pleistocene (i.e. since MIS 5e 122 +/- 6 ka, i.e. kilo annum) apparent uplift rates of 0.04 ± 0.01 mm/yr, (ii) mean Middle Pleistocene eustasy-corrected uplift rates of 0.09 ± 0.03 mm/yr, and (iii) low mean Pleistocene uplift rates of 0.01 mm/yr. Extrapolations of these slow rates combined with geological evidence implies that the formation of the sequences from the Cotentin Peninsula occurred between 3 Ma (Pliocene) and 15 Ma (Miocene), which cannot be narrowed down further without additional research. Along the coasts of Western Europe, sequences of marine terraces and rasas are widespread (169 preserve the MIS 5e benchmark). In Spain, Portugal, S England and other parts of western France, the sequences morphostratigraphy is very similar to that of Cotentin. The onset of such Western European sequences occurred during the Miocene (e.g. Spain) or Pliocene (e.g. Portugal). We interpret this Neogene-Quaternary coastal uplift as a symptom of the increasing lithospheric compression that accompanies Cenozoic orogenies.

Collection and analysis of existing information on applicability of investigation methods for characterizing natural events/processes in a coastal region

International Nuclear Information System (INIS)

Nakayasu, Akio; Niizato, Tadafumi; Yasue, Ken-ichi; Doke, Ryosuke; Shigehiro, Michiko; Tanaka, Takenobu; Aoki, Michinori; Sekiya, Ayako

2011-02-01

The investigation methods for characterizing natural events and processes in a coastal field have been extracted on the basis of analysis of previous research. Collected information is classified into three groups according to the characteristics of natural events/processes and investigation methods. First group is the methods for evaluation of uplift, subsidence and sedimentation rates. Second group is the methods for evaluation of denudation rates. The third group is the methods for reconstruction of the climatic and sea-level changes. Study area, timeframe of the investigation, work sequences, techniques for age-determination, index and objects for characterizing natural events/processes, etc. in each research example were arranged in an 'information spread sheet'. Information on applicability of the each investigation method was extracted from information spread sheet, and was arranged in tabular form. Based on an analysis of the above information, investigation method that can be applied to a coastal region was extracted. The methods and indices are as follows: Uplift rate: the heights of marine terraces are the most important index in an upheaval region. Subsidence and sedimentation rate: the depths of strata underlying an alluvial plain are main indices in a subsidence region. Denudation rate: the features of marine terrace are main indices and the inspection of denudation processes by the use of a numerical simulation is necessary. Climate change: lacustrine deposits are main object for investigation. Sea-level change: reconstruction of relative sea-level change curve including uplift/subsidence factor and paleogeography based on acoustic exploration and the investigation of marine terraces. (author)

Evaluation of Land Use, Land Management and Soil Conservation Strategies to Reduce Non-Point Source Pollution Loads in the Three Gorges Region, China.

Science.gov (United States)

Strehmel, Alexander; Schmalz, Britta; Fohrer, Nicola

2016-11-01

The construction of the Three Gorges Dam in China and the subsequent impoundment of the Yangtze River have induced a major land use change in the Three Gorges Reservoir Region, which fosters increased inputs of sediment and nutrients from diffuse sources into the water bodies. Several government programs have been implemented to mitigate high sediment and nutrient loads to the reservoir. However, institutional weaknesses and a focus on economic development have so far widely counteracted the effectiveness of these programs. In this study, the eco-hydrological model soil and water assessment tool is used to assess the effects of changes in fertilizer amounts and the conditions of bench terraces in the Xiangxi catchment in the Three Gorges Reservoir Region on diffuse matter releases. With this, the study aims at identifying efficient management measures, which should have priority. The results show that a reduction of fertilizer amounts cannot reduce phosphorus loads considerably without inhibiting crop productivity. The condition of terraces in the catchment has a strong impact on soil erosion and phosphorus releases from agricultural areas. Hence, if economically feasible, programmes focusing on the construction and maintenance of terraces in the region should be implemented. Additionally, intercropping on corn fields as well as more efficient fertilization schemes for agricultural land were identified as potential instruments to reduce diffuse matter loads further. While the study was carried out in the Three Gorges Region, its findings may also beneficial for the reduction of water pollution in other mountainous areas with strong agricultural use.

Evaluation of Land Use, Land Management and Soil Conservation Strategies to Reduce Non-Point Source Pollution Loads in the Three Gorges Region, China

Science.gov (United States)

Strehmel, Alexander; Schmalz, Britta; Fohrer, Nicola

2016-11-01

The construction of the Three Gorges Dam in China and the subsequent impoundment of the Yangtze River have induced a major land use change in the Three Gorges Reservoir Region, which fosters increased inputs of sediment and nutrients from diffuse sources into the water bodies. Several government programs have been implemented to mitigate high sediment and nutrient loads to the reservoir. However, institutional weaknesses and a focus on economic development have so far widely counteracted the effectiveness of these programs. In this study, the eco-hydrological model soil and water assessment tool is used to assess the effects of changes in fertilizer amounts and the conditions of bench terraces in the Xiangxi catchment in the Three Gorges Reservoir Region on diffuse matter releases. With this, the study aims at identifying efficient management measures, which should have priority. The results show that a reduction of fertilizer amounts cannot reduce phosphorus loads considerably without inhibiting crop productivity. The condition of terraces in the catchment has a strong impact on soil erosion and phosphorus releases from agricultural areas. Hence, if economically feasible, programmes focusing on the construction and maintenance of terraces in the region should be implemented. Additionally, intercropping on corn fields as well as more efficient fertilization schemes for agricultural land were identified as potential instruments to reduce diffuse matter loads further. While the study was carried out in the Three Gorges Region, its findings may also beneficial for the reduction of water pollution in other mountainous areas with strong agricultural use.

Indications of neotectonic crust motion in Northern Switzerland

International Nuclear Information System (INIS)

Haldimann, P.

1987-01-01

Indications of possible Pleistocene and Holocene tectonic activity in northern Switzerland have been found by an analysis of irregular erosional forms in the subcrop, abnormal gradients of accumulative gravel terraces and particular developments of the river course. (author) 6 refs., 3 figs., 1 tab

Biochar-amended filter socks reduce herbicide losses via tile line surface inlets

Science.gov (United States)

Standing water in depressions and behind terraces in fields with subsurface drainage systems can result in reduced crop yields. This concern can be partially alleviated by installing surface inlets that reduce the duration of ponding. Unfortunately, these inlets provide an open conduit for surface w...

Very large cryoturbation structures of Last Permafrost Maximum age at the foot of the Qilian Mountains (NE Tibet Plateau, China)

NARCIS (Netherlands)

Vandenberghe, J.F.; Wang, X.; Vandenberghe, D.

2016-01-01

Unusually large cryoturbation structures (4-4.5 m amplitude), developed in channel gravels and overbank fine-grained deposits of a river terrace on the NE Tibet Plateau, China, were formed by loadcasting as late Pleistocene-age permafrost degraded. It is suggested that the oversaturation and

78 FR 63963 - Foreign-Trade Zone 1 and 111-New York, New York; Application for Merger and Reorganization Under...

Science.gov (United States)

2013-10-25

... Terminal Facility and Port Ivory Factory, North Washington/ Western Avenues and Richmond Terrace/Western... (.5 acres)--Malca Amit, 153-66 Rockaway Boulevard, Jamaica; and, Site 5 (.57 acres)--World Diamond.../Newark and John F. Kennedy International Airport Customs and Border Protection ports of entry. The...

Evaluation of the on-site impact of water harvesting in southern Tunisia

NARCIS (Netherlands)

Fleskens, L.; Stroosnijder, L.; Ouessar, M.; Graaff, de J.

2005-01-01

Water harvesting techniques (WHT) play an important role in water resources conservation in (semi-) arid environments. However, the impacts of WHT are not clearly understood. This paper presents a method to measure increased water availability to olive (Olea europeae) trees grown on the terraced

Mg/Ca partitioning between aqueous solution and aragonite mineral: a molecular dynamics study

NARCIS (Netherlands)

Ruiz-Hernandez, S.E.; Grau-Crespo, R.; Almora-Barrios, N.; Wolthers, M.; Ruiz-Salvador, A.R.; Fernandez, N.; Leeuw, N.H. de

2012-01-01

We have calculated the concentrations of Mg in the bulk and surfaces of aragonite CaCO3 in equilibrium with aqueous solution, based on molecular dynamics simulations and grand-canonical statistical mechanics. Mg is incorporated in the surfaces, in particular in the (001) terraces,

7 CFR 658.5 - Criteria.

Science.gov (United States)

2010-01-01

..., NRCS field office technical guides, soil potential ratings or soil productivity ratings, land..., fruit trees and vines, field terraces, drainage, irrigation, waterways, or other soil and water... available from the NRCS field offices in each State. Data are from the latest available Census of...

High-resolution, short-range, in-mine geophysical techniques for the delineation of South African orebodies

CSIR Research Space (South Africa)

Van Schoor, Abraham M

2006-07-01

Full Text Available of the respective planar orebodies is relatively easy to predict ahead of mining. On a local, in-mine scale, however, the geometry of these orebodies is far less predictable because of the presence of disruptive geological features such as faults, rolls, terraces...

78 FR 52760 - Application(s) for Duty-Free Entry of Scientific Instruments

Science.gov (United States)

2013-08-26

... invite comments on the question of whether instruments of equivalent scientific value, for the purposes... platforms based on self- assembled DNA nanostructures for studying cell biology. DNA nanostructures will be... 23, 2013. Docket Number: 13-033. Applicant: University of Pittsburgh School of Medicine, 3500 Terrace...

Arc parallel extension in Higher and Lesser Himalayas, evidence ...

Indian Academy of Sciences (India)

2012). The Zimithang study area being only 30 km north- west of Tawang, we presume that the Zimithang zone might ... incised terrace from the river valley is ∼45 m in height. ..... crustal flow in eastern Tibet; Science 276 788–790. Seeber L ...

Characterization of Rain Attenuation and Depolarization at W/V Bands

Science.gov (United States)

2015-07-30

and Louisiana Boulevard. The AR227 weather station is located near the intersection of Tramway Boulevard and Tramway Terrace Street. The distance...low and under-damped resonance frequency. Therefore, the structure was stiffened with braces that were secured to the roof of the building as shown

Ethiopian Journal of Development Research - Vol 37, No 2 (2015)

African Journals Online (AJOL)

Non-market pricing for an improved solid waste management system in Arba Minch Town, Ethiopia · EMAIL FULL TEXT EMAIL FULL TEXT ... Socio-economic and environmental effects of tourism in Konso Terrace and cultural landscape, Ethiopia: perception of local communities · EMAIL FULL TEXT EMAIL FULL TEXT

Two Attentional Models of Classical Conditioning: Variations in CS Effectiveness Revisited.

Science.gov (United States)

1987-04-03

probability is in closer agreement with empirical expectations, tending to lie on a line with slope equal to 1. Experiments in pigeon autoshaping have shown...Gibbon, J., Farrell, L., Locurto, C.M., Duncan, H., & Terrace, H.S. (1980). Partial reinforcement in autoshaping with pigeons. Animal Learning and

Bibliography on Cold Regions Science and Technology Volume 53, Part 2

Science.gov (United States)

1999-12-01

Arctic snow cover information for hydrological investiga - Wright, J.R.53-3036Designing network partitions to improve maintenance Tout- Wohtman,53-3036...832 [1998,eng] 53-1703 Amazonia Effect of dissolved NaCI on freezing curves of kaolinite, moat- Ice complex and cryoplanation terraces on Big Lyakhovsky

77 FR 74186 - Ocean Transportation Intermediary License Applicants

Science.gov (United States)

2012-12-13

... Logistics, Inc. (NVO & OFF), 7685 NW. 80th Terrace, Medley, FL 33166, Officers: Hugo E. Martinez, Secretary... & OFF), 1834 Harden Blvd., Lakeland, FL 33803, Officers: Steven C. Pniewski, Manager (QI), Manuel R. Echevarria, President, Application Type: New NVO & OFF License, Global Wide Logistics, Inc. (NVO), 1937 Davis...

Technical assessment of electric heat boosters in low-temperature district heating based on combined heat and power analysis

DEFF Research Database (Denmark)

Cai, Hanmin; You, Shi; Wang, Jiawei

2018-01-01

This paper provides a technical assessment of electric heat boosters (EHBs) in low-energy districts. The analysis is based on a hypothetical district with 23 terraced single-family houses supplied by both a lowtemperature district heating (LTDH) network and a low-voltage network (LVN). Two case...

Steps on rutile TiO2(110): Active sites for water and methanol dissociation

DEFF Research Database (Denmark)

Martinez, Umberto; Vilhelmsen, Lasse; Kristoffersen, Henrik Høgh

2011-01-01

for each step edge, more stable, reconstructed structures were found for the step edge, while the bulk truncated structures were recovered for the step edge.We demonstrate how oxygen vacancies along these defects have lower formation energies than on flat terraces and how water and methanol...

Neotectonics of the Roer Valley rift system; style and rate of crustal deformation inferred from syn-tectonic sedimentation

NARCIS (Netherlands)

Berg, van den M.W.

1995-01-01

River sediments of the Meuse, Rhine and local Belgian systems have been preserved in various parts of the Roer Valley rift. Age-altitude positions of Meuse terraces provide a detailed record of neotectonic regional uplift. It shows accelerations and decelerations superimposed on a long-term average

Structure of ultrathin Pd films determined by low-energy electron microscopy and diffraction

Energy Technology Data Exchange (ETDEWEB)

Santos, B; De la Figuera, J [Centro de Microanalisis de Materiales, Universidad Autonoma de Madrid, Madrid 28049 (Spain); Puerta, J M; Cerda, J I [Instituto de Ciencia de Materiales, CSIC, Madrid 28049 (Spain); Herranz, T [Instituto de Quimica-Fisica ' Rocasolano' , CSIC, Madrid 28006 (Spain); McCarty, K F [Sandia National Laboratories, Livermore, CA 94550 (United States)], E-mail: benitosantos001@gmail.com

2010-02-15

Palladium (Pd) films have been grown and characterized in situ by low-energy electron diffraction (LEED) and microscopy in two different regimes: ultrathin films 2-6 monolayers (ML) thick on Ru(0001), and {approx}20 ML thick films on both Ru(0001) and W(110). The thinner films are grown at elevated temperature (750 K) and are lattice matched to the Ru(0001) substrate. The thicker films, deposited at room temperature and annealed to 880 K, have a relaxed in-plane lattice spacing. All the films present an fcc stacking sequence as determined by LEED intensity versus energy analysis. In all the films, there is hardly any expansion in the surface-layer interlayer spacing. Two types of twin-related stacking sequences of the Pd layers are found on each substrate. On W(110) the two fcc twin types can occur on a single substrate terrace. On Ru(0001) each substrate terrace has a single twin type and the twin boundaries replicate the substrate steps.

Making Restaurant No. 1 greener

CERN Multimedia

Roberto Cantoni

2010-01-01

The extension of a section of the terrace of Restaurant No. 1, which was part of the infrastructure consolidation programme that began in April 2009, will be completed at the end of this year. The new terrace will have an area of 1770 m² (compared with 1650 m²  today) and will stretch the length of the restaurant extension.   The new building is a striking example of the use of renewable energies, comprising high-performance photovoltaic panels with an innovative sealing system integrated in the roof that cope particularly well with low amounts of sun. The electric cables and connections of each module are hidden and integrated in the roof, giving it a uniform appearance. The roof comprises two rows of 12 modules, each measuring 11.6 m². Their total annual energy production capacity is around 14 MWh. By comparison, the building's estimated annual energy consumption is 98 MWh, depending on the conditions of use.

Interdisciplinary investigation on the recent deformation in the high fertile lowland of the Segura river (Murcia): Hydrogeologic criteria applicable to the study of the neotectonic in the spanish south eastern region

International Nuclear Information System (INIS)

Rodriguez Estrella, T.; Lopez Bermudes, F.

1984-01-01

This neotectonic investigation concentrates on the southern area in the high fertile lowland of the Segura river (23 Km 2 ). Our methodology is various, pointing towards a better understanding of the recent tectonic activity which have taken place in this area. Our methods and techniques have been indirect and direct. Indirect techniques: aerial photography (at different scales and different periods of time), hydrochemistry (over 70 analyses) seismicity (from the end of last century) and vertical electric fathoming probings (64 S.E.V. of AB=1000). Direct techniques: geomorphology (alluvial terraces and loose meanders), mechanic fathoming probings (over 50) and structural cuttings in the ground. Archaeology has contributed to a great extent to clarify the existence of neotectonics in this alluvial terraces and its dating. Lastly, certain hydrogeologic criteria have been analysed concerning the recent deformations of the Spanish Southeast, as well as, some general considerations on the neotectonic of this area on the Iberian Peninsula. (author)

Status and application of α-spectrometric 230Th/234U dating of fossil corals in Ryukyus, Japan and the Philippines

International Nuclear Information System (INIS)

Inagaki, Miyuki; Omura, Akio; Sasaki, Keiichi

2007-01-01

High-precision α-spectrometric 230 Th/ 234 U dating was achieved by recent improvements of measurement system and chemical procedures and enabled critical evaluation of age reliability. We review the status and application of α-spectrometric 230 Th/ 234 U dating of Pleistocene and Holocene corals to reconstruct past sea level changes and tectonic movements in Ryukyus, southwestern Japan and the Philippines in the western rim of circum-Pacific island arcs. The highest terrace in Kikai Island was formed during MIS 5c not MIS 5e that previously reported. Coral reef sediments deposited not only during MIS 5e but also during glacial periods, e.g. MIS 6 and 2, have been found in the Ryukyus. Coral reef sediments formed during MIS 2 were found at ca. 120 m below present sea level off Irabu Island located at 25degN. In addition, it was clear that three terraces developed during MIS 5e, 5c and 5a at Pamilacan Island on the Philippines. (author)

Atomic layer deposition overcoating: tuning catalyst selectivity for biomass conversion.

Science.gov (United States)

Zhang, Hongbo; Gu, Xiang-Kui; Canlas, Christian; Kropf, A Jeremy; Aich, Payoli; Greeley, Jeffrey P; Elam, Jeffrey W; Meyers, Randall J; Dumesic, James A; Stair, Peter C; Marshall, Christopher L

2014-11-03

The terraces, edges, and facets of nanoparticles are all active sites for heterogeneous catalysis. These different active sites may cause the formation of various products during the catalytic reaction. Here we report that the step sites of Pd nanoparticles (NPs) can be covered precisely by the atomic layer deposition (ALD) method, whereas the terrace sites remain as active component for the hydrogenation of furfural. Increasing the thickness of the ALD-generated overcoats restricts the adsorption of furfural onto the step sites of Pd NPs and increases the selectivity to furan. Furan selectivities and furfural conversions are linearly correlated for samples with or without an overcoating, though the slopes differ. The ALD technique can tune the selectivity of furfural hydrogenation over Pd NPs and has improved our understanding of the reaction mechanism. The above conclusions are further supported by density functional theory (DFT) calculations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Does iron inhibit cryptoendolithic microbial communities?

Science.gov (United States)

Johnston, C. G.; Vestal, J. R.; Friedmann, E. I. (Principal Investigator)

1988-01-01

Photosynthetic activity of three cryptoendolithic microbial communities was studied under controlled conditions in the laboratory. In two of these communities, the dominant organisms were lichens, collected from Linnaeus Terrace and from Battleship Promontory. The third community, dominated by cyanobacteria, was collected from Battleship Promontory. Both sites are in the ice-free valleys of southern Victoria Land. Previous efforts have shown how physical conditions can influence metabolic activity in endolithic communities (Kappen and Friedmann 1983; Kappen, Friedmann, and Garty 1981; Vestal, Federle, and Friedmann 1984). Biological activity can also be strongly influenced by the chemical environment. Inorganic nutrients such as nitrate, ammonia, and phosphate are often limiting factors, so their effects on photosynthetic carbon-14 bicarbonate incorporation were investigated. Iron and manganese are two metals present in Linnaeus Terrace and Battleship Promontory sandstones, and their effects on photosynthesis were also studied. The results may add to our understanding of biogeochemical interactions within this unique microbial community.

Rate estimates for lateral bedrock erosion based on radiocarbon ages, Duck River, Tennessee

International Nuclear Information System (INIS)

Brakenridge, G.R.

1985-01-01

Rates of bedrock erosion in ingrown meandering rivers can be inferred from the location of buried relict flood-plain and river-bank surfaces, associated paleosols, and radiocarbon dates. Two independent methods are used to evaluate the long-term rates of limestone bedrock erosion by the Duck River. Radiocarbon dates on samples retrieved from buried Holocene flood-plain and bank surfaces indicate lateral migration of the river bank at average rates of 0.6-1.9 m/100 yr. Such rates agree with lateral bedrock cliff erosion rates of 0.5-1.4 m/100 yr, as determined from a comparison of late Pleistocene and modern bedrock cliff and terrace scarp positions. These results show that lateral bedrock erosion by this river could have occurred coevally with flood-plain and terrace formation and that the resulting evolution of valley meander bends carved into bedrock is similar in many respects to that of channel meanders cut into alluvium. 11 references, 5 figures

Landscape controls and vertical variability of soil organic carbon storage in permafrost-affected soils of the Lena River Delta

DEFF Research Database (Denmark)

Siewert, Matthias Benjamin; Hugelius, Gustaf; Heim, Birgit

2016-01-01

To project the future development of the soil organic carbon (SOC) storage in permafrost environments, the spatial and vertical distribution of key soil properties and their landscape controls needs to be understood. This article reports findings from the Arctic Lena River Delta where we sampled 50...... in the permafrost. The major geomorphological units of a subregion of the Lena River Delta were mapped with a land form classification using a data-fusion approach of optical satellite imagery and digital elevation data to upscale SOC storage. Landscape mean SOC storage is estimated to 19.2 ± 2.0 kg C m− 2. Our...... results show that the geomorphological setting explains more soil variability than soil taxonomy classes or vegetation cover. The soils from the oldest, Pleistocene aged, unit of the delta store the highest amount of SOC per m2 followed by the Holocene river terrace. The Pleistocene terrace affected...

Carbon monoxide oxidation on a Au(111 surface modified by spontaneously deposited Ru

Directory of Open Access Journals (Sweden)

ROLF-JÜRGEN BEHM

2001-04-01

Full Text Available The spontaneous deposition of Ru on Au(111 was performed in 10-3 M RuCl3 + 0.5 M H2SO4 solution. The obtained surface was characterized by STM under potential control in 0.5 M H2SO4 solution. The coverage of the Au(111 terraces by deposited Ru was estimated by STM to be 0.02 ML. Step decoration could be noticed in the STM images, which indicates that the steps, as lined defects, are active sites for the nucleation of Ru monolayer islands, while the random distribution of Ru nuclei, observed on the terraces indicates point defects as active sites. The electrocatalytic activity of Au(111 surface modified by spontaneously deposited Ru was studied towards CO oxidation. The significant enhancement in the reaction rate compared to CO oxidation on a pure Au(111 surface, indicated that the edges of the deposited Ru islands were the active sites for the reaction.

Control and follow-up of fly ash roads - Communication and Acceptance; Kontroll och uppfoeljning av askvaegar - Kommunikation och acceptans

Energy Technology Data Exchange (ETDEWEB)

Macsik, Josef; Edeskaer, Tommy; Hellman, Fredrik

2011-10-15

The report is aimed at those who perform or plan to perform stabilization of the unbound layers or terrace gravel roads or industrial areas, with binder where a major binder component is fly ash from bio-peat or coal fuel. Stabilization of unbound layers of road structures is a promising technique from technical, economical and environmental point of view. The need of demonstration projects on road sections to show the relationship of laboratory measurements and field measurements are great in order to promote this stabilization technique. Results from follow-up of several stabilized distances and industrial surfaces are presented, where the fly ash is a binder component. The results complement the guidance, Munde et al. (2006) respect to durability, environmental characteristics on several years of perspective. Our hope is that report will serve as a support for the implementation of demonstration projects of stabilized terrace or unbound layers of fly ash as binder component.

Pleistocene-Holocene sedimentation of Solimões-Amazon fluvial system between the tributaries Negro and Madeira, Central Amazon

Directory of Open Access Journals (Sweden)

Eliezer Senna Gonçalves Júnior

Full Text Available ABSTRACT: In the scope of Solimões-Amazon fluvial system between the Negro and Madeira tributaries, three levels of Quaternary fluvial terraces overlie the Alter do Chão and Novo Remanso formations further than 100 km southward its current main channel. Smooth undulated topography presenting low drainages density formed by sparse secondary plain channels and rounded lakes characterizes these deposits. Internally, they show point bars morphology constituted by intercalated layers of mud (silt and clay and sand forming an inclined heterolithic stratification. The asymmetric distribution of fluvial terraces allied to the records of old scroll-bars features and paleochannels in many extensions of the Solimões River suggests the predominance of a meander pattern between 240 to 6 kyears. On the other hand, the development of the current anabranching pattern took place in the last six kyears due to the Holocene sea-level rise, besides the action of neotectonics and rainforest establishment related to the increase of humidity in Amazonia.