scholarly journals Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
David Benavente ◽  
Marli de Jongh ◽  
Juan Carlos Cañaveras
Keyword(s):  
Chemical Effect ◽  
Salt Weathering ◽  
Capillary Water ◽  
Material Loss ◽  
Weathering Processes ◽  
Geochemical Study ◽  
Pigeon Droppings ◽  
Deterioration Process ◽  
Dehydration Processes ◽  
Physical And Chemical

This investigation studies the physical and chemical effect of salt weathering on biocalcarenites and biocalcrudites in the Basilica of Our Lady of Succour (Aspe, Spain). Weathering patterns are the result of salty rising capillary water and water lixiviated from pigeon droppings. Surface modifications and features induced by material loss are observable in the monument. Formation of gypsum, hexahydrite, halite, aphthitalite and arcanite is associated with rising capillary water, and niter, hydroxyapatite, brushite, struvite, weddellite, oxammite and halite with pigeon droppings. Humberstonite is related to the interaction of both types of waters. Analysis of crystal shapes reveals different saturation degree conditions. Single salts show non-equilibrium shapes, implying higher crystallisation pressures. Single salts have undergone dissolution and/or dehydration processes enhancing the deterioration process, particularly in the presence of magnesium sulphate. Double salts (humberstonite) have crystals corresponding to near-equilibrium form, implying lower crystallisation pressures. This geochemical study suggests salts precipitate via incongruent reactions rather than congruent precipitation, where hexahydrite is the precursor and limiting reactant of humberstonite. Chemical dissolution of limestone is driven mainly by the presence of acidic water lixiviated from pigeon droppings and is a critical weathering process affecting the most valuable architectural elements present in the façades.

scholarly journals Lithogenic hydrogen supports microbial primary production in subglacial and proglacial environments

2020 ◽  
Vol 118 (2) ◽  
pp. e2007051117
Author(s):  
Eric C. Dunham ◽  
John E. Dore ◽  
Mark L. Skidmore ◽  
Eric E. Roden ◽  
Eric S. Boyd
Keyword(s):  
Primary Production ◽  
Chemical Weathering ◽  
Enrichment Culture ◽  
Mineral Surfaces ◽  
Silicate Mineral ◽  
Weathering Processes ◽  
Order Of Magnitude ◽  
Lag Times ◽  
Carbonate Catchment ◽  
Physical And Chemical

Life in environments devoid of photosynthesis, such as on early Earth or in contemporary dark subsurface ecosystems, is supported by chemical energy. How, when, and where chemical nutrients released from the geosphere fuel chemosynthetic biospheres is fundamental to understanding the distribution and diversity of life, both today and in the geologic past. Hydrogen (H2) is a potent reductant that can be generated when water interacts with reactive components of mineral surfaces such as silicate radicals and ferrous iron. Such reactive mineral surfaces are continually generated by physical comminution of bedrock by glaciers. Here, we show that dissolved H2 concentrations in meltwaters from an iron and silicate mineral-rich basaltic glacial catchment were an order of magnitude higher than those from a carbonate-dominated catchment. Consistent with higher H2 abundance, sediment microbial communities from the basaltic catchment exhibited significantly shorter lag times and faster rates of net H2 oxidation and dark carbon dioxide (CO2) fixation than those from the carbonate catchment, indicating adaptation to use H2 as a reductant in basaltic catchments. An enrichment culture of basaltic sediments provided with H2, CO2, and ferric iron produced a chemolithoautotrophic population related to Rhodoferax ferrireducens with a metabolism previously thought to be restricted to (hyper)thermophiles and acidophiles. These findings point to the importance of physical and chemical weathering processes in generating nutrients that support chemosynthetic primary production. Furthermore, they show that differences in bedrock mineral composition can influence the supplies of nutrients like H2 and, in turn, the diversity, abundance, and activity of microbial inhabitants.

scholarly journals The Effect of Weathering on Salt Release from Coal Mine Spoils

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 760
Author(s):  
Melinda Hilton ◽  
Mandana Shaygan ◽  
Neil McIntyre ◽  
Thomas Baumgartl ◽  
Mansour Edraki
Keyword(s):  
Particle Size ◽  
Coal Mine ◽  
Chemical Weathering ◽  
Physical Weathering ◽  
Particle Size Fractions ◽  
Mine Spoils ◽  
Weathering Processes ◽  
Three Samples ◽  
Two Samples ◽  
Physical And Chemical

Coal mine spoils have the potential to create environmental impacts, such as salt load to surrounding environments, particularly when exposed to weathering processes. This study was conducted to understand the effect of physical and chemical weathering on the magnitude, rate, and dynamics of salt release from different coal mine spoils. Five spoil samples from three mines in Queensland were sieved to three different particle size fractions (<2 mm, 2–6 mm, and >6 mm). Two samples were dispersive spoils, and three samples were nondispersive spoils. The spoils were subjected to seven wet–dry cycles, where the samples were periodically leached with deionised water. The rate, magnitude, and dynamics of solutes released from spoils were spoil specific. One set of spoils did not show any evidence of weathering, but initially had higher accumulation of salts. In contrast, broad oxidative weathering occurred in another set of spoils; this led to acid generation and resulted in physical weathering, promoting adsorption–desorption and dissolution and, thus, a greater release of salts. This study indicated that the rate and magnitude of salt release decreased with increasing particle size. Nevertheless, when the spoil is dispersive, the degree of weathering manages salt release irrespective of initial particle size. This study revealed that the long-term salt release from spoils is not only governed by geochemistry, weathering degree, and particle size but also controlled by the water/rock ratio and hydrological conditions of spoils.

The formation of silt from quartz dune sand by salt-weathering processes in deserts

1979 ◽  
Vol 2 (2) ◽  
pp. 105-112 ◽  
Author(s):  
A.S. Goudie ◽  
R.U. Cooke ◽  
J.C. Doornkamp
Keyword(s):  
Salt Weathering ◽  
Dune Sand ◽  
Weathering Processes

Physical and Chemical Methods of Methane Utilization in Ukrainian Coal Mines

2018 ◽  
Vol 277 ◽  
pp. 147-156 ◽  
Author(s):  
Ella Maksymova ◽  
Mykola Ovchynnikov ◽  
Roman Lysenko ◽  
Svitlana Kostrytska
Keyword(s):  
Oil And Gas ◽  
Coal Mines ◽  
Energy Resource ◽  
Hydrate Formation ◽  
Chemical Effect ◽  
Chemical Methods ◽  
Associated Gas ◽  
Physical And Chemical ◽  
Methane Utilization ◽  
Hydrate Formation Process

Associated gas of coal and minor oil deposits emitting into the atmosphere is considered to be valuable energy resource requiring proper utilization both from the economic and environmental viewpoints. It is proposed to develop mobile gas-hydrate plants to utilize associated gas of mines and minor oil and gas deposits. Hydrogenerating technology to collect and utilize coalmine methane immediately at the degassing wells of coal mines and oil extraction platform has been developed. Thermobaric parameters along with physical and chemical effect upon hydrate-formation process have been substantiated and selected. Certain degree of mechanical impact as well as magnetic field and ultrasound influence upon the process of hydrate formation has been proved. The technology will make it possible to obtain end product within the degassing area for its further transportation to consumers at long distances.

scholarly journals Hydrothermalism Associeted To Ediacarian Volcanism Of Ait Sawn And Tissouktai (Eastern Anti- Atlas, Morocco)

2016 ◽  
Vol 12 (24) ◽  
pp. 316
Author(s):  
R. Zahour ◽  
G. Zahour ◽  
Y. Zerhouni ◽  
S. Alikouss ◽  
Z. Baroudi ◽  
...  
Keyword(s):  
Active Faults ◽  
Fault Reactivation ◽  
Tectonic Structures ◽  
Weathering Processes ◽  
South West ◽  
Field Investigations ◽  
Geochemical Study ◽  
Volcanic Facies ◽  
Basic Volcanic ◽  
Geological Formations

In the South East of Ouarzazate (south west of the Saghro massif, Anti Atlas) outcrop the geological formations of Ait Sawn and Tissouktai. These, attributed to the Ediacaran (or terminal Neoproterozoic), consist of basic volcanic facies, intermediate and acid intercalated with pyroclastics and epiclastic levels. This set is traversed locally by acidic veins. The rocks studied suffered intense weathering processes marked by the development of secondary minerals which are also formed in the hydrothermal veins and at the expense of the primary magmatic minerals and mesostasis. The main paragenesis of mineralisation consists of hematite, malachite, chalcocite, pyrite, barite, epidote, quartz, chlorite, calcite, albite, sericite and iron oxides. Paleogeography sector is governed by inherited active faults of the Pan African base. Magmatism studied seems to be guided by these tectonic lineaments during the terminal Proterozoic extension. The reactivation of these tectonic structures, after the Cambrian, and probably during the Variscan and / or Atlasic, is certain. Field investigations, supplemented by microscopic and geochemical study, indicate that much of the mineralization associated with volcanic Southwest Massif Saghro, is related to a hydrothermalisme contemporary with the stage of fault reactivation.

scholarly journals Power Measurement by Calorimetric Method Using Water Infrequency Range Between 1.7 Mhz To 3 Mhz

2018 ◽  
Vol 7 (3.32) ◽  
pp. 106 ◽  
Author(s):  
F Shokrollahi ◽  
K K. Lau ◽  
W H. Tay ◽  
L S. Lai
Keyword(s):  
Electrical Power ◽  
Power Measurement ◽  
Chemical Effect ◽  
Calorimetric Method ◽  
Liquid Volume ◽  
Co2 Absorption ◽  
Ultrasonic Power ◽  
Absorption Process ◽  
Ultrasound Technique ◽  
Physical And Chemical

Absorption is one of the most established processes for CO2 capturing. However, the current technologies used in this process suffer from several drawbacks. Meanwhile, the ultrasound technique is proposed as a new alternative technology to assist the CO2 absorption process due to both its physical and chemical effects. Yet, the chemical effect is still under developments. Between all the influencing parameters, the ultrasonic power and the frequency are the vital key parameters to investigate sonochemical effects during the CO2    absorption process. The aim of this paper is to measure the ultrasonic power of an ultrasonic vessel. The total electrical power measured by using the voltage and the flow. Simultaneously, the ultrasonic power determined by using the calorimetric method. The measurements were done by using water with different volumes and repeated for three different frequencies. The results showed that almost 51% of the electrical power converted into the ultrasonic power and were independent of liquid volume.  

Study the Effects of Shari Lake on the Physical and Chemical Properties for Groundwater in Samarra City

2020 ◽  
Vol 398 ◽  
pp. 173-178
Author(s):  
Mustafa A. Theyab ◽  
Baraa M. Ibrahim Al-Hilali ◽  
Mohammed A. Fadhil
Keyword(s):  
Ground Water ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Ground Structure ◽  
Geochemical Study ◽  
Result Show ◽  
Physical And Chemical ◽  
And Chemical Properties

We design hydro geochemical study to show the effect of Shari Lake on Samarra groundwater. tow samples (Jelam 1,Jelam 2 ) that nearby Shari lake and other samples taken from different location from Samarra city ( Efraz ,SDI factory , Golden Mosque, Samarra university ). Then sent samples to specific laboratory for chemical and microbial test .the result shows the locations (Jelame 1, Jelame 2) have highest value in PH, but SDI factory location has highest value in Sulfate. The result show affect ground water in this city by salt and mineral that found in watershed and ground structure specially limestone that flow throw ground that lead to dissolve salt and mineral then arise the value of studied data.

The Physical and Chemical Effect of Manganese Oxides on Automobile Catalytic Converters

1994 ◽  
Author(s):  
Allen A. Aradi ◽  
Joseph W. Roos ◽  
Ben F. Fort ◽  
Thomas E. Lee ◽  
Robert I. Davidson
Keyword(s):  
Manganese Oxides ◽  
Chemical Effect ◽  
Catalytic Converters ◽  
Physical And Chemical

FATE OF CRUDE OIL SPILLED IN A SIMULATED ARCTIC ENVIRONMENT

1977 ◽  
Vol 1977 (1) ◽  
pp. 461-463 ◽  
Author(s):  
C. MacGregor ◽  
A. Y. McLean
Keyword(s):  
Crude Oil ◽  
Oil Spill ◽  
The Arctic ◽  
Oil Composition ◽  
Liquid Chromatograph ◽  
Weathering Processes ◽  
Mixing Energy ◽  
Ultimate Fate ◽  
Physical And Chemical ◽  
Crude Oil Spill

ABSTRACT A simulated Arctic crude oil spill was investigated by monitoring physical and chemical changes in a laboratory spill of Guanipa (Venezuelan) crude. The spill consisted of one gallon of crude on 100 gallons of synthetic seawater contained in a fiberglass tank fitted with a wave generator and a controlled radiation system, all located in an environmental chamber held at 2°C. Changes in oil composition were monitored using a gas liquid Chromatograph. Evaporation removed the largest quantity of material from the spill, the rate varying directly with the exposure time to solar radiation. Solution or sinking removed only minimal quantities of oil although the influence of these factors increased with time. The most notable physical change was the rapid formation of stable emulsions. These emulsions formed discrete lumps commonly referred to as “tarballs.” The formation of tarballs occurred within a few days after the spill and they remained stable over the four-month duration of the experiment. Their formation drastically reduced weathering effects by removing the bulk of the oil from contact with the air/seawater interface. It was concluded that a crude oil spill in the Arctic could contribute significantly to tarball pollution of northern oceans. Tarball formation is not limited, therefore, to warm waters and occurs independently of weathering processes. It would appear that tarball formation depends more on the chemical composition of the oil and the rate of formation depends upon the available wave mixing energy. The ultimate fate of oil spilled in Arctic regions could be in the form of persistent tarballs.

Sign in / Sign up

Export Citation Format

Share Document