Geochemistry of Sub-Depositional Environments in Estuarine Sediments: Development of an Approach to Predict Palaeo-Environments from Holocene Cores

In the quest to use modern analogues to understand clay mineral distribution patterns to better predict clay mineral occurrence in ancient and deeply buried sandstones, it has been necessary to define palaeo sub-environments from cores through modern sediment successions. Holocene cores from Ravenglass in the NW of England, United Kingdom, contained metre-thick successions of massive sand that could not be unequivocally interpreted in terms of palaeo sub-environments using conventional descriptive logging facies analysis. We have therefore explored the use of geochemical data from portable X-ray fluorescence analyses, from whole-sediment samples, to develop a tool to uniquely define the palaeo sub-environment based on geochemical data. This work was carried out through mapping and defining sub-depositional environments in the Ravenglass Estuary and collecting 497 surface samples for analysis. Using R statistical software, we produced a classification tree based on surface geochemical data from Ravenglass that can take compositional data for any sediment sample from the core or the surface and define the sub-depositional environment. The classification tree allowed us to geochemically define ten out of eleven of the sub-depositional environments from the Ravenglass Estuary surface sediments. We applied the classification tree to a core drilled through the Holocene succession at Ravenglass, which allowed us to identify the dominant paleo sub-depositional environments. A texturally featureless (massive) metre-thick succession, that had defied interpretation based on core description, was successfully related to a palaeo sub-depositional environment using the geochemical classification approach. Calibrated geochemical classification models may prove to be widely applicable to the interpretation of sub-depositional environments from other marginal marine environments and even from ancient and deeply buried estuarine sandstones.

Occurrence State of Carbon and Electrolyte in Anode Carbon Residue From Electrolytic Aluminum

Anode carbon residue is produced in the production of electrolytic aluminum. Its properties need to be studied for secondary utilization. In this paper, mineralogy of anode carbon residue from an electrolytic aluminum plant in Guizhou was studied. The anode residue chemical composition, structure, mineral composition, occurrence state of main elements, etc, was investigated. The results show that: Anode carbon residue is mainly composed of 14 minerals such as cryolite, cryolithionite, elpasolite and graphite. Among them, the opaque minerals are mainly graphite and the transparent minerals are mainly cryolite. Carbon in the form of independent mineral occurrence in graphite; fluoride in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite and fluorite; aluminum in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite, aluminium oxide and magnesium aluminate; sodium in the form of independent mineral occurrence in cryolite, cryolithionite, elpasolite. The mineralogical characteristics and occurrence state of carbon and electrolyte were studied, which provided a basis for the separation and recovery of carbon and electrolyte in anode carbon residue.

Sveite from the Northeastern San Joaquin Valley, California

ABSTRACT Sveite [KAl7(NO3)4(OH)16Cl2·8H2O] first described from Venezuela and material recently collected from northern California have similar X-ray diffraction patterns and chemical compositions. The main difference in the chemical composition is the absence of significant chlorine and sulfate in the sveite from California. The changes observed by X-ray diffraction upon hydration and the SEM images of the crystals suggest a layered atomic structure. Water-extractable NO3 in the Venezuelan sveite sample is isotopically enriched in δ15N and δ18O and likely was affected by the microbial process of denitrification. In contrast, the extractable nitrate from the California sveite is less isotopically enriched than the Venezuelan mineral and there is only modest evidence that denitrification had affected its isotopic composition. Overall, the nitrate in the California sveite is isotopically similar to nitrate present in acidic soils overlying the mineral occurrence, suggesting a general biogenic source of uric acid from bird feces for the mineral-bound nitrogen.

Spatial Trends in Mineral Abundances across Tyrrhena Terra on Mars derived from Geomorphological and Mineralogical Mapping

<p>Tyrrhena Terra hosts an intriguing variety of aqueously altered materials accompanied by unaltered mafic rocks. Our study region extends from the southern rim of the Isidis impact basin, including the Libya Montes region, southward to the Hellas Basin rim (Fig. 1). The NW part is dominated by lava flows from Syrtis Major that grade southwards into the TT highlands, dissected by fluvial channels and overprinted by abundant impact craters. These landforms together with lobate and fan-shaped deposits within impact craters are evidence for a variable history of erosion and deposition. Ancient phyllosilicate-rich materials have been exposed and uplifted from the subsurface, as they often occur in crater ejecta and central crater uplifts.</p><p>Our previous studies used CRISM spectral data together with CTX, HiRISE, and HRSC images as well as their derived topography data to create geomorphological maps of the southern Isidis region and Tyrrhena Terra. These datasets were used to map and characterize the types and occurrences of phyllosilicates, chlorite, opal, zeolites, carbonates, olivines, and pyroxenes and to assess the relationships between selected aqueous outcrops and surface features.</p><p>In this work, we build on these results by seeking correlations between aqueous mineral detections with our geomorphological map to assess 1) whether or not there are relationships between specific units and mineral occurrences, and 2) if there are trends across the study region in terms of mineral occurrence and abundance.</p><p>The mineralogical map originates from a study that spans not only the inter-Isidis-Hellas region, but also extends northwards to Nili Fosse and westwards to Terra Sabea. The focus of that study was on the metamorphic- and hydrothermally-related alteration history using CRISM targeted and mapping data, including hundreds of calibrated MTRDR images. These mineral detections were available to us as a mapped shape file, enabling us to assess the minerals in context with the geomorphological map. We utilized ESRI’s ArcGIS system and conducted multiple statistical queries in terms of mineral occurrence/type versus map unit in order to reveal possible trends within and across the study region.</p><p>Fe/Mg-phyllosilicates are the dominant aqueous mineral type within the study region and are more abundant in the central region compared to the proximity of either the Isidis or Hellas impact basin. Chlorites increase in abundance with distance from both impact basins, which could be an indication of hydrothermal processes from geothermal flux. The large Hellas impact event appears to have produced more varied temperatures and water chemistries, resulting in increased mineral variability near its rim.</p>

Studying ore field structure and rock properties of the Delken deposit to substantiate the optimal pit walls design

Introduction. In order to determine a key design parameter substantiated by technical-economic and geomechanical analyses, the critical angle of slope of the nonmining wall in Delken deposit pit which depends on the properties and the state of rock building up the wall and its structures, and in order to determine the forms and the elements of mineral occurrence, the authors carried out comprehensive research consisting of the of deposit’s geological and structural features determination, including endogeneous and exogeneous jointing, and the detailed examination of physical and mechanical properties of rock and ore. Research aim is to study geological-structural properties of the deposit in order to analyze and substantiate the optimal and safe structure of pit walls when developing ore at the Delken gold deposit. Methodology. The structural features of Vodorazdelny ground were determined by carrying out the comparative analysis of geological sections and maps, structural description of core and building the scheme of rock blocking according to the level of destruction during deposit opencast. Physical and mechanical properties of rock were determined in laboratory conditions. Numerical analysis of wall stability was fulfilled with modern software. Results. The comprehensive research consisting of the analysis of mining and geological conditions of development, deposit’s geological and structural features determination, detailed examination of the properties of rock building up the slopes of the quarry have made it possible to substantiate the rational design of pit walls when developing ore reserves of the deposit. Summary. The results of the research carried out at the deposit may be applied when substantiating the safest technology of uncovering the deposit and the safest mining sequence.

Application of Contemporary Extraction Techniques for Elements and Minerals Recovery from Stinging Nettle Leaves

Stinging nettle (Urtica dioica L.) is a perennial plant belonging to the Urticaceae family. Several studies have reported the presence of the different classes of chemical compounds, which expressed a beneficial effect on human health. Among them there are elements and minerals that are essential for the proper functioning of organism. Mineral occurrence requires analytical data about the content. For such purposes was developed and validated a method based on the optical emission spectroscopy coupled with inductively coupled plasma (ICP-OES). Minerals and elements were extracted using two conventional methods (Soxhlet and maceration) and two non-conventional (ultrasound- and microwave-assisted techniques). The extracts were analyzed resulting in high diversity in the composition. Non-conventional techniques showed better results, since those extracts possessed high content of the macroelements and iron as well, instead the toxic elements were found in trace amount