Search results for "Sediment"

Latvijas ūdeņu vides pētījumi un aizsardzība: Referātu tēžu krājums

2016

Baltijas jūras sedimentu ekoloģiskā kvalitāte un to potenciāla ietekme uz sānpelžu attīstību

2017

Mūsdienās aktualizējies jautājums par sedimentu ekoloģiskās kvalitātes noteikšanas metodēm. Ekotoksikoloģiskie pētījumi kopumā raksturo Baltijas jūras sedimentu ekoloģisko kvalitāti kā “labu”/“vidēju” (attiecīgi 52% un 25%), salīdzinoši labāku sedimentu kvalitāti uzrādot Botnijas jūrā un Rīgas līcī, bet pārsniegtu labas vides kvalitātes robežu (>GES) - Somu līcī, Gdaņskas līcī un Belta jūrā. Biotestu standartsugām (Monoporeia affinis, Corophium volutator un Hyalella azteca) un darbā rekomendētajām sugām (Bathyporeia pilosa, Pontogammarus robustoides un Gmelinoides fasciatus) novērojama atšķirīga jutība potenciāli piesārņotu Baltijas jūras sedimentu klātbūtnē, kas norāda uz būtiski atšķirīgu…

A review of runoff generation and soil erosion across scales in semiarid south-eastern Spain

2011

Climate, lithology, soil and especially, intense land use/cover changes, make SE Spain very vulnerable to runoff generation and water erosion leading to loss of nutrients and organic matter and to infrequent but devastating floods, reservoir siltation and mass failures. This susceptibility has led to heavy economic investment and research efforts since the 1980s, making this region a worldwide reference for understanding the hydrology and geomorphology of semiarid ecosystems. Runoff and soil erosion have been intensively studied throughout the last decades in various natural ecosystems as well as in abandoned farmlands. Research has considered a wide range of methods and spatial and tempora…

Estimation of historical vertical displacement at the Capo d’Orlando coast (Northern Sicily) based on submerged grinding wheels of Greek age

2009

Data for: Accumulation of metals and changes in the composition of freshwater lake organic sediments during the Holocene

2020

Distribution of metals in freshwater sediment strata formed during the Holocene in the territory of Latvia has been studied rather insufficiently. Considering the large volume of accumulated organic matter in sediments, studies of the content of metal elements in sediments can help to determine the peculiarities of metal accumulation process in limnic systems and biogeochemical cycling of metals. Lake Pilvelis, located in the eastern part of Latvia (the northern part of Europe), was selected as the study site. Lake Pilvelis is a small lake of a glacial origin, and more than 90% of its depression is filled with organic-rich sediments, such as gyttja or freshwater sapropel, with an average th…

The N Variscan margin of the Ruhr coal district (Western Germany): structural style of a buried thrust front?

1988

The Ruhr coal district represents part of an external fold and thrust belt of the Variscan orogen in central Europe. Extensive mining exposed molasse-type, coal-bearing clastic sequences of Upper Carboniferous age, deformed by folding and thrusting. Thrusts range in scale from decameters to 40 kilometers along strike but displacements are below 2.5 km. They are distributed in various stratigraphic levels and no regional detachment horizon is exposed. Displacement is mainly towards NW (towards the foreland) but also towards SE. The thrusts are bound to stockwerk-tectonics and die out towards depth frequently antithetic to the exposed strata. Folds vary in wavelength from decameters to more t…

Laminated carbonate deposits in Roman aqueducts: Origin, processes and implications

2013

Carbonate deposits in Roman aqueducts of Patara and Aspendos (southern Turkey) were studied to analyse the nature of their regular layering. Optical microscopy and electron-backscattered diffraction results show an alternation of dense, coarsely crystalline, translucent laminae composed of bundles and fans of elongate calcite crystals with their c-axes parallel to the long axis, and porous, fine-grained laminae with crystals at near-random orientation. The ?18O and ?13C data show a strong cyclicity and anti-correlation, whereby high and low ?18O values correspond to dense columnar and porous fine-grained laminae, respectively. Geochemical analyses show similar cyclic changes in carbonate co…

Hydrogen underground storage—Petrographic and petrophysical variations in reservoir sandstones from laboratory experiments under simulated reservoir …

2018

Abstract Fluctuating energy production by renewables is one of the main issues in transition times of energy production from conventional power plants to an energy production by renewables. Using excess produced electricity (windy/sunny periods) to convert water to oxygen and hydrogen and storing the hydrogen in depleted oil-, gas fields or sedimentary aquifer structures would provide the option to recover and convert hydrogen to electricity in periods with an energy demand. Research focus is here the pore space in the geological underground where still few studies exist. In static batch experiments up to six weeks long, under different reservoir-specific conditions; regarding pressure, tem…

Pesticide contamination in water and sediment of the aquatic systems of the Natural Park of the Albufera of Valencia (Spain) during the rice cultivat…

2021

The Natural Park of the Albufera (Valencia, Spain) is a Mediterranean wetland where rice cultivation dominates the agricultural activity. The purpose of this study was to offer broader information about the current state of the wetland assessing the contamination by pesticides in four aquatic habitats during the rice cultivation period in 2016. Liquid chromatography with tandem mass spectrometer (UHPLC-MS/MS) was used to determine the pesticides in water and sediment samples from the rice fields, Lake Albufera and irrigation and outlet channels. 21 pesticides were detected in our samples (seven already forbidden by European legislation). Higher values than 10000 ng L of accumulated pesticid…

Late Pleistocene Detrital Sediment Yield of the Jura Glacier, France

2001

AbstractMeasures of present-day glacial erosion vary widely with the technique employed. This paper quantifies the glacial material trapped in a proglacial lake during the Würm glacial period. The Combe d'Ain site was occupied by a meltwater lake where all the detrital material entering it from the Jura glacier accumulated. Sediment yield is computed from three factors: (1) the size of the sediment source area, (2) the length of time the system operated, and (3) the volume of sediment trapped. The sediment budget of the lake system suggests a detrital sediment yield of 4400±1700 metric tons per square kilometer and per calendar year. This represents a denudation rate of 1.6±0.6 mm per year,…