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  • Open access
  • 32 Reads
Mapping of the space change of Oued Ali Mountains (Mascara, Algeria) by Landsat optical imagery

Analyzing and understanding the dynamics of physical environments, due to quarrying, is a fundamental issue in detecting change, in semi-arid natural environments. The mountains of Ouled Ali (Beni Chougrane Mountains) contain highly unstable areas that make the region of Sig (wilaya of Mascara) vulnerable. Observation and qualification of landscape changes is the easiest way for career monitoring. This exploitation has a direct and indirect impact on the ecosystem and the surrounding environment.

The slopes of Aoud Asma Mountain (Ouled Ali Mountains) affected by the exploitation of quarries are the subject of our study whose purpose is to characterize their kinematics. To do this, the means are many and varied; each of them has specific properties as regards the type of use, the quantity measured and its scope and accuracy. The change of space mapping by a correlation of optical images is one of these methods.

The work methodology adopted is based on the application of Principal Component Analysis (PCA), Intensity, Hue and Saturation of rock (IHS) and Normalized Vegetation Index (NDVI). Two Landsat images were used: Landsat5 image (25th September, 1999) and Landsat7 image (02nd September, 2011). It is followed by a comparison with the ground truth and a mapping of physical space dynamics of the study area.

The PCA, IHS and NDVI results allowed us to highlight the bare soils, and the degradation of forest cover and halophyte vegetation. Moreover, the quarrying contributed largely, in some places, to the change of space of Aoud Asma Mountain of Ouled Ali Mountains.

  • Open access
  • 21 Reads
Non-Destructive Photon Activation Analysis in Paleontology

Paleontological samples are rare and non-renewable, which makes their study require non-destructive methods. Of interest to paleontologists are both the physical and chemical characteristics. Physical characteristics are routinely studied with non-destructive methods; however, chemical studies tend to require destructive methods unless samples are very small or only the surface compositions are of interest. One potential technique for non-destructive elemental analysis is photon activation analysis (PAA). PAA is a versatile, broad-spectrum, multi-element analysis tool with low sensitivities, capable of analyzing large samples without any alteration, preserving the physical characteristics.

Recent work has applied PAA to fossils and their source matrices in an attempt to correlate provenance through trace element analysis. PAA was shown to be non-consumptive and able to identify 20+ elements in samples with sub-ppm sensitivities. From that work, several lessons were learned and the non-destructivity of the technique was better characterized. PAA doesn’t have one standardized methodology, as it varies depending on the sample type. As such, from the lessons learned from the previous research, a standard method of applying PAA non-destructively to paleontological samples has been developed and will be presented in the following paper.

  • Open access
  • 16 Reads
Promoting Earth sciences teaching-learning in the Italian schools: a research of learning objects, effective educational approaches, to improve skills and competences

In the Italian context, where Earth sciences are poorly considered in the education system and in the common thinking, to promote a widespread and deep-rooted culture of natural hazards, the danger inherent in the geological evolution of the territory, the responsible use of the environment, the perception of phenomenon as part of the dynamics of the Earth is a priority.

The goal of this work is to promote Earth sciences education, particularly in the Italian schools, to increase the interest of students towards geosciences, to enhance teachers’ competences in the use new and more effectives educational inductive and adductive approaches, using tools, paths and learning objects, based on hands-on practices, experimented in schools of all levels of education. The unifying principle is the research of models and guidelines to produce effective practices, easy to be shared or realized in the school.

All the educational tools have been tested and evaluated and are collected in easy kits now freely usable. All the materials and the educational paths are presented in a working booklet freely downloadable. The result is an increasing sensitiveness towards Earth science teaching -learning, a widespread awareness towards the need of promoting competences and skills and a growing knowledge of the inquiry approaches. Some experiences are in fact tested also referring to the acquired skills and competences of the students before and after their use.

This experience has shown also that Earth science is in effect the discipline that more promote citizenship and transversal skills and, furthermore develops the ideas of system and complexity.

  • Open access
  • 30 Reads
Adsorption of rare earth elements from aquaeous solutions using geopolymers

Rare earth elements, also known as lanthanides, are important components of many latest technology applications and are widely used in the industrial sector, medicine and agriculture. Although lanthanides are ubiquitous in the environment, their increasing use in aforementioned sectors over the last few decades provided them with a title of "new pollutants".

Different methods are nowadays applied for removal of various pollutants from wastewaters, whereby the emphasis is placed on the adsorption due to its simplicity, high efficiency and low cost. The most common adsorbents for metal ions are active carbon, clay minerals, biomaterials and solid wastes in the form of geopolymers [1,2]. Previous studies reported an excellent adsorption capacity of fly ash based geopolymers for removal of heavy metals from aqueous solutions, e.g. Cu, Pb, Cr, Cd, Ni, Zn, Cs [1-3]. Given the fact that lanthanides are not significantly studied in this regard, our aim was to investigate the ability of the geopolymer matrices to remove lanthanides from the model aqueous solutions.

For this purpose, the geopolymers were prepared using the Raša coal ash (Istria, Croatia) as starting material. The Raša coal characteristics, summarized by Medunić et al. [4], are as follows: total moisture 5.80-19.1 wt%, ash content 10.3-23.9 wt%, carbon 58.3-67.5 wt%, hydrogen 4.10-5.00 wt%, sulfur (org.) 7.90-10.6 wt%, oxygen 5.90-12.9 wt%, nitrogen 1.00-1.80 wt%, and an average content of rare earth elements 81.1 mg kg-1 [5].

The Raša coal ash, previously sieved through 2 mm sieve, was activated with a sodium silicate and sodium hydroxide solutions to prepare paste specimens. The fresh pastes were exposed to heat curing in a laboratory oven at 75°C for 24 h. After two weeks of ageing at room temperature, subsamples of prepared geopolymers were used for adsorption experiments.

Aqueous solutions containing rare earth elements were prepared from multielement reference standard (Analytika, Prague, Czech Republic) containing Ce, La, Nd and Pm (100 ± 0,2 mg L-1) and Dy, Er, Eu, Gd, Ho, Lu, Sc, Sm, Tb, Tm, Y and Yb (20 ± 0,4 mg L-1). The subsamples (0.5 g) of prepared geopolymers were added to 50 mL of the prepared multielement solution containing 1 mg L-1 of rare earth elements. At certain time intervals of the adsorption experiment (5 min, 15 min, 30 min, 60 min and 120 min), an aliquot of the solution (~2-3 mL) was separated by filtration through 0.45 µm syringe filter. The obtained solutions were analyzed by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) using an Element 2 instrument (Thermo, Bremen, Germany).

The results indicate almost complete removal of lanthanides from the initial model solution within two hours. These preliminary data are an incentive for additional experiments that will provide a detailed insight into the mechanism of adsorption of lanthanides on geopolymer matrices, including the precursor and geopolymer characterization.

Keywords: rare earth elements, geopolymers, adsorption

References

[1] Al-Zboon, K., Al-Harahsheh, M.S., Hani, F.B., 2011. Fly ash-based geopolymer for Pb removal from aqueous solution. J. Hazard. Mater. 188, 414–421

[2] Muzek, M.N., Svilovic, S., Zelic, J., 2014. Fly ash-based geopolymeric adsorbent for copper

ion removal from wastewater. Desalin. Water Treat. 52, 2519–2526

[3] López, F.J., Sugita, S., Tagaya, M., Kobayashi, T., 2014. Metakaolin-based geopolymers

for targeted adsorbents to heavy metal ion separation. J. Mater. Sci. Chem. Eng. 2, 16–27

[4] Medunić, G., Rađenović, A., Bajramović M., Švec, M., Tomac, M., 2016a. Once grand, now forgotten: what do we know about the superhigh-organic-sulfur Raša coal? Min. Geol. Petrol. Eng. Bull. 27-45; doi: 10.17794/rgn.2016.3.3.

[5] Fiket, Ž., Medunić, G., Kniewald, G., 2016. Rare earth element distribution in soil nearby thermal power plant. Environ. Earth Sci. 75, 598, 1-9; doi: 10.1007/s12665-016-5410-2.

  • Open access
  • 38 Reads
RapidScat Sigma-0 Measurements Validation
Published: 14 June 2018 by MDPI AG in 1st International Electronic Conference on Geosciences session Poster section

NASA RapidScat is the first Ku-Band wind scatterometer that flown in non-Sun-synchronous orbit. RapidScat is capable of measuring ocean vector winds over the full diurnal cycle, instead of observing a given location at a fixed time of day. The RapidScat operated onboard the International Space Station between September 2014 and August 2016. This unique platform facilitated global contiguous geographical sampling between the ±56 latitude. Non-Sun-synchronous orbit also enables the overlap with other satellite instruments that have been flying in Sun-synchronous orbits. To serve as a cross-calibration reference with other instruments, RapidScat must be carefully calibrated. This paper presents the double-difference methodology to scatterometry. The methodology has been adopted for the cross-instrument calibration between RapidScat and QuikScat scatterometers simultaneously orbiting the Earth on- board two independent satellite platforms. The statistical analysis and measurements biases have been evaluated between the two scatterometers. Calculated biases may be used for measurement correction and reprocessing. This work summarizes the comparison measurements data in the period from January 2015 to August 2016. This research was performed under the grant from the NASA Headquarters and oth RapidScat and QuikScat datasets were provided by the NASA Physical Oceanography Distributed Active Archive Center (PODAAC) at the Jet Propulsion Laboratory.

  • Open access
  • 13 Reads
Glassy spherules from the Cretaceous-Paleogene boundary in Bąkowiec profile
(Skole Nappe, Polish Outer Carpathians)
Published: 14 June 2018 by MDPI AG in 1st International Electronic Conference on Geosciences session Others

Mass extinction in the Cretaceous-Paleogene boundary, which took place about 66 mln years ago, is well known almost to everybody because of the extinction of the largest prehistorical reptiles, which have ever walked on the Earth- the dinosaurs. For scientists this event is important because of one of the cause, meteorite impact. Evidences of interference of extraterrestrial material are searched since this argument was ever made. The most desirable evidences, which can be find in the Cretaceous-Paleogene boundary sediment are: iridium anomaly, shocked minerals and glassy spherules. Researches were made in Bąkowiec profile, situated in Skole Nappe of Outer Carpathians, in the area of the Łańcut city. Boundary interval was appointed there relying on biostratigraphy. Last occurance of Abathomphalus mayaroensis, which indicate late Maastrichtian and first occurance of Paleocene Guembelitria cratacea were taken under the consideration (Gasiński i Uchman, 2011). Glassy spherules, which was dissociated from the sediment, were divided into four types: carbonate, irony, silicate and apatite due to their chemical compound.

  • Open access
  • 18 Reads
Paving the road for sustainability through global understanding of heritage

The contemporary understanding that heritage comprises the whole bio and geosphere, due to the direct or indirect anthropic impact all over the planet, allows for a global understanding of heritage that pervades all domains of sustainability research.

The current debate on the so-called Anthropocene calls for revisiting past strategies of humans-environment disruptive episodes, in order to better understand the global implications of everyday actions and the wider implications of the interactions between technology and sociocultural structure. Anthropogenic evidences are the core of heritage, and their assessment allows tracing processes in terms of landscape management, illustrating how concepts like "land-use" or "resources exploitation" emerges from a utilitarian solutions-oriented approach, whereas concepts like "resilience" or "sustainability" are embedded in a dilemmas-facing approach, which encompasses problems but frames them within a longer-term reasoning and foresight.

This is the relevance of heritage at large and of geoheritage in particular: a cultural understanding of past equilibriums, and disruptions, as compounds of resources, technology, logistics and sociocultural processes. This has relevant consequences for current global challenges, as in the case of low demographic density territories, i.e., those where a third of the world population still lives, corresponding to over 95% of the lithosphere.

This paper is a review study, being the discussion based on pertinent literature revision regarding how these territories may offer best examples of integrated responses, engaging geosciences as a backbone for interaction with tourism, technology or societal strategies. In this context, no remote sensing data or other analytical data were processed to support the results, since this is not the focus of the paper.

  • Open access
  • 47 Reads
Morphological and spectrophotometric investigation of the layering of comet 67P/Churyumov-Gerasimenko

On 6 August 2014 the ESA’s International space mission Rosetta finally approached comet 67P/Churyumov-Gerasimenko and escorted it for the next 26 months. The particular bi-lobed shape of comet 67P suggests that it is the result of a gentle collision of two distinct bodies, which experienced a similar evolutionary history (Sierks et al., 2015). The OSIRIS imaging system provided evidence of the presence of morphological terraces that allowed the identification of thick sets of strata nearly continuous that individually envelope both lobes (Massironi et al., 2015). This pervasive layering has then been modelled by measuring the orientation of the terraces, up to define a three-dimensional ellipsoid-based model (Ellipsoidal Model, Penasa et al., 2017).

Moreover, the OSIRIS data acquired in the NUV-VIS-NIR wavelength range by the high resolution Narrow Angle camera (NAC) allowed to perform a spectrophotometric investigation of the layering, highlighting a correlation between the surface reflectance of the consolidated material of the nucleus and the structural elevation defined by the onion-shell Ellipsoidal Model. The method implies a two-classes supervised classification on the cometary surface identified as outcropping material and has been implemented separately for each lobe. The classification allowed to distinguish two major envelopes characterized by different brightness, which can be associated with different textural properties of the layers and/or a difference in the abundances of refractory materials.

  • Open access
  • 39 Reads
Development of the statistical model for monitoring salinization in the Mekong Delta using remote sensing data and in-situ measurements

The current sea level rise has been causing coastal countries, especially the Delta, to be increasingly vulnerable to salt intrusion through the river network. Salt intrusion is often complicated, unpredictable and influential on a large area. Salinization reduces crop yield, soil degradation, decreases water quality, severely affects agricultural production, environment as well as the life of the people. This article presents the methodology for developing a statistical model for monitoring salinity intrusion in the Mekong Delta based on the integration of satellite imagery and in-situ measurements. The Landsat OLI & TIRS imageries in dry season 2014 were used to examine the correlation between spectral reflectance bands, principal component bands and corresponding salinity measurements on the day of the obtain imagery at 11 monitoring stations. The selected regression model showed a good correlation with the exponential function of the principal component bands’ spectral reflectance value and in-situ measurements (R> 0.8). Simulation of the salinity distribution along the river shows that the intrusion of 4g / l salt boundary from the estuary to the inner field more than 50km. The developed model will be an active contribution, providing managers with adaptation and response solutions suitable for intrusion in the estuary as well as the inner field of the Mekong Delta.

  • Open access
  • 20 Reads
Martian Analogue of Pampas de La Joya: an update and future implications

Mars-like environments on Earth are used as a model to guide research related to the possible habitability in the Red Planet. This work aims to evaluate the geology, geomorphology and soil petrology of the Pampas de La Joya Desert in southern Peru, and describe the current research in the area. Using a multidisciplinary approach, we analyze the different Mars-like soils that compose the floor of the desert emphasizing some Mars-like features with respect to its acting geologic processes, the habitability potential under extreme aridity, and its suitability to sustain microorganisms or their remains. Finally, we briefly describe the current projects which use these Mars-like soils in Pampas de La Joya and their impact in Astrobiology, such as Potatoes on Mars, MARS-PJ, and KillaLab mission.

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