Trace Rare Earth Elements Research Articles

Syn-Faulting Calcite Ages: Constraint for the Late Mesozoic Deformation of the Ningzhen Mountain, Eastern China

It is difficult to date a brittle fault because of the absence of effective dating methods. Recently, calcite U-Pb dating has drawn the attention of many researchers and has been successfully applied to constrain the age of brittle deformation. The South China Block (SCB) has experienced multiphase deformations characterized by widespread brittle faults and folds, which has led to significant debate on the Mesozoic dynamic mechanism and deformational phases. A syn-faulting calcite vein that occurred in the Permian limestones of the Ningzhen Mountain region was analyzed using U-Pb dating and geochemistry techniques in this paper. The U-Pb dating results display multiphase activities with two mixed ages of 109.9±5.8 Ma (MSWD=46, n=231) and 117.2±2.4 Ma (MSWD=3.6, n=150). The age of 117.2±2.4 Ma likely represents the timing of the brittle faults. Trace elements and rare earth elements data indicate that these fault-related calcites are mainly derived from host limestones and unrelated to Cretaceous magmatic activity. These faults formed in a tectonic reactive period and dormant time of the adakitic magma in the Lower Yangtze region.

Petrographic and geochemical characterization of the Middle\u2012Upper Jurassic Fe\u2013Mn crusts and mineralizations from Monte Inici (north-western Sicily): genetic implications

Fe–Mn concretions and mineralizations, associated with condensed horizons and hardground, are significant archives in ancient carbonate rocks. Their petro-chemical study allows an assessment of the palaeoenvironmental context in which they were formed also connected to their biotic or abiotic origin. At the western side of the Monte Inici (Fornazzo section, north-western Sicily) a well exposed outcrop of condensed pelagic limestones (Rosso Ammonitico facies: Middle‒Upper Jurassic) is well-known and thoroughly studied. In this section, the base of the Rosso Ammonitico facies consists of a very condensed level rich in fossils with a variable thickness deposited from the early Bathonian to the early/middle Callovian. It is characterized, at the top, by the noticeable presence of Fe–Mn concretions, typical of the Tethyan Jurassic and related to very low sedimentation rates. For this study, Fe–Mn crusts and mineralizations from the Fornazzo section were investigated using X-ray diffraction, scanning electron microscopy, X-ray fluorescence, ICP and stable-isotope mass spectrometry. The collected samples, deposited in submarine conditions (as testified by stable oxygen and carbon isotopes), have been subdivided in two typologies with different macroscopic and mineralogical features. The Fe–Mn crusts consist of hematite, todorokite and birnessite and are characterized by a relatively low Mn/Fe ratio. Their content in trace elements, rare earths and yttrium (REY) is compatible with a hydrogenetic origin involving the oxy-hydroxides colloids precipitation directly from seawater. Microbially mediated processes are here testified by the recognition of filamentous and coccoid-shaped microstructures referable to coexistence of chemosynthetic fungi and photosynthetic cyanobacteria and accounting for a deposition in the deep euphotic zone. An average growth rate of ~ 8.5 mm/Myr for the Fe–Mn crusts, estimated by cobalt concentrations, suggests a time elapsed for deposition of ~ 3.5 ± 1 Myr. This value is compatible with the stratigraphic gap embracing the time span from the early/middle Callovian to the middle Oxfordian. In the neighbouring pelagic limestones, Fe–Mn deposits are present in the form of micro-dendrites mainly consisting of pyrolusite, sometimes associated with carbonato-fluorapatite. The geochemical composition gives evidence of a prevalent early diagenetic origin with precipitation, at the sediment/water interface or in the first centimeters of sediments, of metals diffused from the crusts as consequence of fluctuating redox conditions. Although the well-preserved Frutexites texture is commonly related to a microbial activity, other bacterial microstructures have not been recognized, having probably been obliterated during the growth of the dendrites. Nevertheless, it is possible to suppose a deepening in the bathymetry consistent with the involvement of chemosynthetic microorganisms in the formation of Frutexites structures.

Causes of variations of trace and rare earth elements concentration in lakes bottom sediments in the Bory Tucholskie National Park, Poland

The objective of this study was to analyse spatial variability of the trace elements (TEs) and rare earth elements (REEs) concentration in lake bottom sediments in Bory Tucholskie National Park (BTNP); Poland. The following research questions were posed: which factors have a fundamental impact on the concentration and spatial variability of elements in bottom sediments, which of the elements can be considered as indicators of natural processes and which are related to anthropogenic sources. The research material was sediments samples collected from 19 lakes. The concentrations of 24 TEs and 14 REEs were determined. The analyses were carried out using the inductively coupled plasma mass spectrometry (ICP-QQQ). Cluster analysis and principal component analysis were used to determine the spatial variability of the TEs and REEs concentrations, indicate the elements that are the indicators of natural processes and identify potential anthropogenic sources of pollution. The geochemical background value (GBV) calculations were made using 13 different statistical methods. However, the contamination of bottom sediments was evaluated by means of the index of geo-accumulation, the enrichment factor, the pollution load index, and the metal pollution index. The BTNP area is unique because of its isolation from the inflow of pollutants from anthropogenic sources and a very stable land use structure over the last 200 years. This study shows high variability of TE and REE concentrations in lake sediments. The values of geochemical indices suggest low pollution of lakes bottom sediments. It was found that TEs originated mainly from geogenic sources. However, the concentrations of Li, Ni, Sc, Se, Be, Se, Ag, Re, Tl, Cd, Sb and U may be related to the impact of point sources found mainly in the Ostrowite Lake. Almost all REEs concentrations were strongly correlated and their presence was linked to with geochemical processes. The elements allowing to identify natural processes and anthropogenic pollution sources were Cr, Co, Cu, Ag, Cd, Zn, Bi, Re, Ba, Al and Rb in TEs group and Nd, Gd, Yb, Lu, Eu, Dy and Ce in REEs group. The analysis shows high spatial variability of TE and REE concentrations in lake sediments. The values of geochemical indices point to low pollution of lakes sediments. The anthropogenic sources only for two lakes had an impact on concentrations of selected TEs and REEs. The analyses allowed to identify elements among TEs and REEs documenting geochemical processes and those indicating anthropogenic sources of pollution.

Zooming in REE and Other Trace Elements on Conodonts: Does Taxonomy Guide Diagenesis?

Conodont elements are calcium phosphate (apatite structure) mineralized remains of the cephalic feeding apparatus of an extinct marine organism. Due to the high affinity of apatite for rare earth elements (REE) and other high field strength elements (HFSE), conodont elements were frequently assumed to be a reliable archive of sea-water composition and changes that had occurred during diagenesis. Likewise, the crystallinity index of bioapatite, i.e., the rate of crystallinity of biologically mediated apatite, should be generally linearly dependent on diagenetic alteration as the greater (and longer) the pressure and temperature to which a crystal is exposed, the greater the resulting crystallinity. In this study, we detected the uptake of HFSE in conodont elements recovered from a single stratigraphic horizon in the Upper Ordovician of Normandy (France). Assuming therefore that all the specimens have undergone an identical diagenetic history, we have assessed whether conodont taxonomy (and morphology) impacts HFSE uptake and crystallinity index. We found that all conodont elements are characterized by a clear diagenetic signature, with minor but significant differences among taxa. These distinctions are evidenced also by the crystallinity index values which show positive correlations with some elements and, accordingly, with diagenesis; however, correlations with the crystallinity index strongly depend on the method adopted for its calculation.

Zircon U-Pb ages and provenance characteristics of the Zhiluo Formation sandstones and the formation background of the uranium deposit in Huangling area, Ordos Basin, China

The newly discovered medium-scale Huangling uranium deposit is located in the Shuanlong area of the southeast Ordos Basin. This paper presents the systematic geochemical and zircon U-Pb studies on the Zhiluo Formation sandstones in the Huanling area. The data obtained play an important role in deducing the provenance and tectonic setting of the source rocks. The results show that the lower part of the Zhiluo Formation is mainly composed of felsic sedimentary rocks. The source rocks originated from a continental island arc environment in terms of tectonic setting. U-Pb ages of detrital zircons obtained can be roughly divided into three groups: 170–500 Ma, 1600–2050 Ma, and 2100–2650 Ma. Based on the characteristics of trace elements and rare earth elements (REE) and the zircon U-Pb dating results, it is considered that the Cryptozoic Edo provenance of the Zhiluo Formation mainly includes magmatic rocks (such as granodioritic intrusions) and metamorphic rocks (such as gneiss and granulite) in the orogenic belts on the northern margin of the North China Plate and in the Alxa Block. Based on sedimentological and petrological results, it can be concluded that the provenance of clastic sediments in the Zhiluo Formation was in north-south direction. The preconcentration of uranium is relatively low in the Lower Zhiluo Formation in the Huangling area. Meanwhile, the paleocurrent system in the sedimentary period is inconsistent with the ore-bearing flow field in the mineralization period, which restricts the formation of large-scale and super-large-scale uranium deposits and ore zones in the southeast Ordos Basin. The understanding of provenance directions will provide crucial references for the Jurassic prototype recovery and paleo-geomorphology of the Ordos Basin and the prediction of potential uranium reservoirs of the basin.©2021 China Geology Editorial Office.

MAJOR AND TRACE ELEMENT COMPOSITIONS IN GROUNDWATER OF AWE AREA, PARTS OF THE MIDDLE BENEUE TROUGH-NORTHCENTRAL NIGERIA

A Hydrogeochemical study was carried out in Awe town and environs. The aim of the research was to determine the major, trace and rare earth elements content of the waters and their suitability for domestic, agricultural and industrial uses. Fifteen water sources from hand dug wells, a spring, pond and boreholes were collected and analysed. Inductively Coupled Plasma Mass Spectrophotometer was used to analyse the major cations trace elements and rare earth elements, Ion Chromatography was used to detect the anions and bicarbonate by titration method. In an attempt to determine the species of the trace elements in the waters, modeling was carried out using the WATEQ4F. Generally both the trace and the rare earth elements appear to be low in all the water sources and metal species obtain in the area indicate a dominantly reducing environment. Probable reasons for the low content of the trace elements may be the insolubility of their minerals, complexation , adsorption to clays and some oxides which has immobilized them. Chlorine/Bromine ratios indicate source of saline water (Cl/Br = 1,961) in the free flowing artesian borehole at Old Awe town to be evaporitic in origin. Four groundwater facies types were obtained in the study area; Ca+Mg-HCO3, Na+K-HCO3, NaCl, and Mg-SO4. Physico-chemical parameter, trace elements and their species determined in the area indicate that except for the acidity of the water, over eighty percent of water sources are fresh and soft and therefore good for general domestic uses. Percentage sodium, Sodium Absorbtion Ratios, magnesium hazards and salinity hazards also show that except for three sample locations, all other samples are within values recommended for agricultural purposes. Industries like Rubber manufacturing, sugar processing, textile mills, dairy product manufacturing and paper industry can be situated in the study area.

Alkali fusion co-precipitation/cation exchange/extraction enrichment for determination of trace rare earth elements in rocks by inductively coupled plasma mass spectrometry

In this paper, three separation and pre-enrichment methods of Mg(OH)2 and Fe(OH)3 co-precipitation, cation exchange and 1-phenyl-3-methyl-4-benzoyl-pyrazolone (PMBP) extraction were established by sodium peroxide alkali fusion digestion. Ca, Na and K, etc. were virtually eliminated from the analysis solutions using three sample processing procedures, thereby avoiding potential matrix interference and mass spectrometry interference due to high salt content. The detection limits of three methods were 0.0009-0.0076 mg/kg，0.0011-0.0062 mg/kg，0.0023-0.0114 mg/kg, respectively；the relative deviations of the determined rare earth elements (REEs) were -6.9-7.6%, -9.1-6.6% and -8.4-12.3%，respectively. The %RSD values of the three methods were lower than 10%, demonstrating good precision. The fit for purpose of the results was also evaluated by the quality criteria test proposed by the International Geological Correlation Programme (IGCP), from which it can be deduced that the three methods were adequate considering geochemical mapping application. The three sample processing procedures can be applied for the determination of rare earth elements in rocks.

Determination of trace rare earth elements in uranium ore samples by triple quadrupole inductively coupled plasma mass spectrometry

A method for the determination of REEs in uranium ore samples by ICP-MS/MS with O2reaction and mass-shift detection.

Application of Deep Learning Algorithms in Determination of Trace Rare Earth Elements of Cerium Group in Rocks and Minerals

Since the breakthrough of deep learning in object classification in 2012, extraordinary achievements have been made in the field of target detection, but the high time and space complexity of the target detection network based on deep learning has hindered the technology from application in actual product. To solve this problem, first of all, this paper uses the MobileNet classification network to optimize the Faster R‐CNN target detection network. The experimental results on the rare earth element detection data set show that the MobileNet classification network is not suitable for optimizing the Faster R‐CNN network. After that, this paper proposes a classification network that combines VGG16 and MobileNet, and uses the fusion network to optimize the Faster R‐CNN target detection network. The experimental results on the rare earth element detection data set show that the Faster R‐CNN target detection network optimized by the fusion classification network has the advantages of using VGG16 and MobileNet’s Faster R‐CNN target detection network to detect rare earth elements. The innovation of this article is that the results on 5 time series data sets show that CDA‐WR has better predictive performance than other ELM variant models. The effect of determining trace cerium elements in rocks and minerals is increased by more than 50%, based on deep learning. The algorithm studies the methods of target detection and recognition and integrates it into the intelligent robot used in this subject, giving the robot the ability to accurately detect the target object in real time.

Deciphering the Iron Provenance on a Medieval Building Yard: The Case of Bourges Cathedral

This paper presents the provenance study of the iron reinforcements of Bourges Cathedral (13th c.): the links of a 100 m long iron chain, surrounding the eastern parts of the cathedral at the triforium level and 4.5 to 5 m long tie-rods consolidating the arches of the inner aisle at the same level. The analytical methodology is based on the determination of trace rare earth elements analyses by LA-ICP-MS in the slag inclusions of the artefacts and in the slag found on candidate production sites combined with statistical approaches. This chemical approach is crossed with archaeological and historical studies on the monument itself and on the production sites. Ninety-nine iron samples were analyzed on the bars and chains and 238 iron slags from 3 presumed areas of supply. For the first time, iron circulation and trade around a single building yard over a time of 30 to 40 years is studied with a precision never obtained before with historical sources. It shows that mainly four different metallurgical districts, local and more distant, supplied the building yard, mostly depending on the construction phases and also on the types of iron armatures needed.

Morphology evolution and enhanced magnetostriction of (Fe0.81Ga0.19)99.9Tb0.1 crystals prepared by liquid metal cooling Bridgman directional solidification

Previously the magnetostriction of FeGa alloys was enhanced in melt spun ribbons due to the solid solution of trace rare earth elements. Unfortunately, applications of the ribbons are limited. Here, (Fe0.81Ga0.19)99.9Tb0.1 crystals were prepared by liquid metal cooling Bridgman directional solidification over the wide withdraw rate range of 7.2–18000 mm/h. With the increasing withdraw rate, an evolution from<001>-oriented single crystals possessing cellular morphology, to<001>-oriented polycrystals possessing dendritic morphology, and then to randomly-oriented polycrystals was observed. Simultaneously, the solid solution of trace Tb element was promoted, which was evidenced by the decrease of the Tb-rich precipitates and the strengthened magnetocrytalline anisotropy energy. As a result, the magnetostriction effect was significantly enhanced. Large magnetostriction of 390 ppm, which was 30% higher than that of binary Fe0.81Ga0.19 crystal, was realized in the<001>-oriented (Fe0.81Ga0.19)99.9Tb0.1 crystal grown at a withdraw rate of 3600 mm/h.

Highly Enhanced Hot Ductility Performance of Advanced SA508-4N RPV Steel by Trace Impurity Phosphorus and Rare Earth Cerium

Advanced SA508-4N RPV steel samples, unadded, P-added, and P+Ce-added, are investigated on their hot ductility behavior. Hot tensile tests are carried out in the temperature range of 750 to 1000 °C through a Gleeble 1500D machine. It is demonstrated that the deformation temperatures of all the three steels are located in the austenite single-phase region. There is no ductility trough present for the P+Ce-added steel, but the unadded one exhibits a deep ductility trough. The reduction of area (RA) of the former is always higher than 75% and increases with rising temperature until reaching ~95% at 900 °C or above, whereas the lowest RA value of the latter is only ~50% at 850 °C. Microanalysis indicates that the grain boundary segregation of P and Ce takes place in the tested P+Ce-added steel. This may restrain the boundary sliding so as to improve the hot ductility behavior of the steel. Furthermore, the addition of P and Ce is able to facilitate the occurrence of the dynamic recrystallization (DR) of the steel, lowering the initial temperature of DR from ~900 to ~850 °C and thereby enhancing the hot ductility performance. Consequently, the combined addition of P and Ce can significantly improve the hot ductility of SA508-4N RPV steel, thereby improving its continuous casting performance and hot workability.

Mineralogy and origin of the alkaline Nsungwe Formation tuffs of the Rukwa Rift Basin, southwestern Tanzania

The incipient phases of continental rift development remain enigmatic, as early rift sequences are rarely exposed, or poorly preserved in the geologic record. Here, we present petrographic and geochemical analyses of heavy mineral separates from pervasively weathered volcanic horizons intercalated within syn-rift sedimentary deposits from the Rukwa Rift Basin, southwestern Tanzania. These Oligocene (25–26 Ma) ashfalls represent the first magmatic products associated with the initiation of rifting in the western branch of the East African Rift System (EARS). In this work, we combine detailed single crystal petrography with in-situ geochemistry to characterise an alkaline volcanic mineral assemblage consisting of titanite, phlogopite, fluorapatite, clinopyroxene, Ti-rich andradite, sanidine, pyrochlore, nepheline, cancrinite, Fe-sulphide (pyrrhotite), calcite, Na-REE‑carbonate and peralkaline silicate melt. These minerals are significantly enriched in trace elements, particularly Ba, Sr and rare earth elements (REE), with REE + Y contents consistent with derivation from peralkaline phonolitic melts. Placed in context of EARS development, these tuffs display the hallmarks of explosive alkaline‑carbonatite volcanism in their resistant minerals and inclusions; the nature and occurrence of which is consistent with early rift progression elsewhere in the EARS. Importantly, we showcase the depth of extractable petrographic information preserved in extensively weathered volcanic ash horizons deposited into an active continental rift basins. Such an approach may have significant implications for recognising early volcanogenic sequences in continental rift zones worldwide, but particularly in other segments of the western branch of the EARS.

Trace Element Export From the Critical Zone Triggered by Snowmelt Runoff in a Montane Watershed, Provo River, Utah, USA

The Critical Zone is an important source of trace elements to headwater streams during the snowmelt runoff period, yet the mechanisms of trace element release are poorly characterized. To evaluate changes in water chemistry in response to snowmelt, we measured trace element and major ion concentrations at three sites in the upper Provo River in northern Utah, USA, over a five–year period spanning years with below– and above–average discharge. We also sampled snowpack, ephemeral streams, and soil water to investigate trace element sources. The river drains siliciclastic bedrock above the upper site, carbonate rocks between the upper and middle sites, and volcanic rocks between the middle and lower sites, with minimal anthropogenic impacts in the watershed. Concentrations of specific trace metals (Be, Al, Cu, and Pb) and rare earth elements (represented by La and Y) increased during snowmelt runoff each year at all three sites, with decreasing concentrations from upstream to downstream. In contrast, major ion concentrations, including Ca2+ and SO42-, were similar year–round at the upper site and were diluted during snowmelt at the lower sites, with increasing concentrations from upstream to downstream. The snowmelt runoff period (April–June) accounted for >84% of the annual trace element loading, with most trace element inputs occurring above the upper sampling site. Concentration–discharge (C–Q) relationships revealed variations in solute behavior from upstream to downstream. For example, at the upstream site the trace elements had a slight positive slope in log C–log Q space, while Ca2+ and SO42- had zero slope. At the downstream sites, the trace elements had a strong positive slope and Ca2+ and SO42- had a negative slope. Trace element concentrations were relatively low in snowpack but elevated in ephemeral streams and soil water, suggesting that flushing of shallow soils by snowmelt causes increased trace element concentrations with positive C–Q relationships in the upper part of the river. Trace element loads propagate downstream where concentrations are diluted by groundwater inputs from carbonate bedrock. Our results demonstrate that soil water flushing in the Critical Zone at the headwaters of mountain streams is an important control on downstream water chemistry.

Evaluation of trace metals and rare earth elements in mantis shrimp Oratosquilla oratoria collected from Shandong Province, China, and its potential risks to human health

This study provided the primary data of selected trace elements and rare earth elements from 120 samples of mantis shrimp Oratosquilla oratoria (O. oratoria) caught from three sites in the Shandong Province, China and evaluated the potential health risk of shrimp consumption from this region. The calculation of estimated daily intake (EDI), target hazard quotient (THQ) and total target hazard quotient (TTHQ) showed that the contents of all target TREs were below respective permitted limits recommended by China, with the exceptions of Cd and iAs levels. In addition to pollution, results indicated that TREs concentrations in O. oratoria were also impacted by characteristics of O. oratoria. The distribution patterns of REEs in O. oratoria did not differ from those in the sediment and other marine organisms, following the abundance rule. Consumption of O. oratoria from Shandong Province is potentially harmful to human health due to high levels of Cd and iAs.

Source area-weathering, provenance and tectonic setting of the campanian - Maastrichtian clay sequences in the Lower Benue Trough of Nigeria

Clay deposits are abundant within the Lower Benue Trough (LBT) of Nigeria. The chemical compositions and other attributes of some of these deposits, aside their uses, have not been extensively studied and documented. These natural resources are important in the understanding of the geological processes with reference to the source area-weathering, provenance and tectonic setting of the precursors, using the major, trace and Light Rare Earth Element (LREE) compositions of the clay samples. The aim of this investigation was to understand the geochemistry of the clay deposit, beyond the already known functional applications, for which 18 raw clay and 14 separated <2 μm clay fraction from LBT (Nigeria) were collected and analysed.The SiO2 (64.61–90.28 wt%), Al2O3 (5.10–19.22 wt%), Fe2O3 (0.28–3.99 wt%) and LOI (2.70–11.10 wt%) contents of the clay are characteristic of quartz-rich weathered sediments with kaolinitic clay mineral assemblage. The calculated Chemical Index of Alteration (CIA) (91.17–99.79), Plagioclase Index Alteration (PIA) (99.31–99.87) and Chemical Index of Weathering (CIW) (99.34–99.87), as well as, the geochemical parameter (R~0.2) and alpha indices of Ca (28.87 α AlCa < 297) is by far mobile than Ba (1.14 α AlBa < 7.12), Sr (1.24 α AlSr < 11.33), Rb (1.61 α AlRb < 19.03), Mg (11.19 α AlMg < 95.79) and Na (35.24 α AlNa < 150.52) suggested chemical weathering associated with feldspar decomposition into kaolinite and subsequent deposition in the rifted LBT. The LREE and Y concentrations in the clay samples suggested enrichment during the weathering and kaolinization processes. The La–Th-Sc and Eu/Eu* versus [Gd/Yb]N diagram indicated a granitic gneiss precursor. Major elements discriminant-function multi-dimensional diagram, DF1 (arc-rift- col) versus DF2 (arc-rift- col), for high-silica sediments revealed a continental rift tectonic setting. The campanianMaastrichtian clay sequences in the Lower Benue Trough of Nigeria is a quartz-rich kaolinitic clay derived from chemical weathering of Proterozoic granitic gneiss. The clay was deposited in a continental rift tectonic setting, under a tropical climatic condition.

Multistage dolomitization and formation of ultra-deep Lower Cambrian Longwangmiao Formation reservoir in central Sichuan Basin, China

The deeply buried dolostones in the Lower Cambrian Longwangmiao Formation at Central Sichuan Basin of China are a crucial hydrocarbon exploration target. However, the origin of various types of dolomite for these carbonate reservoirs has not been well understood. In this study, petrological studies, geochemical analyses including C, O and Sr isotopes, in-situ trace elements and rare earth elements, and fluid inclusions analyses are performed in order to uncover the dolomitization mechanisms. The results show that an initial pervasive replacive dolomitization phase (Md, D1 and D2) was followed by volumetrically less important cement phases (D3, D4, D5, D6 and calcite). The δ18O values and element concentrations (e.g., Na and Sr) appear to suggest that this early dolomitization was caused by reflux of slightly modified seawater. In the shallow burial realm, influx of meteoric water led to a decrease in Fe content (from 1000 ppm down to 70 ppm) and ∑REE content (from 34.22 ppm down to 9.56 ppm) in early diagenetic D3 dolomite with more negative δ18OSMOW values. This early meteoric water flux may have created considerable dissolution porosities. The D3 and D6 dolomite cements were interpreted as the result of dolomite dissolution and reprecipitation due to burial compaction. The D4, D5 dolomites and late calcite cements display markedly positive Eu anomalies suggesting the presence of hydrothermal fluid. Some late diagenetic calcites with negative δ13C values as low as −5‰ V-PDB and relatively higher Y/Ho ratio of ca. 36.9 were interpreted to be derived from thermochemical sulfate reduction (TSR). The effects of hydrothermal fluid and TSR on reservoir qualities seem to be minor in this case. Hence, this study emphasizes the role of late diagenetic preservation of primary and early diagenetic porosity in the formation of economically important, ultra-deep dolostone reservoirs in sedimentary basins.

Geoquímica de las rocas plutónicas del batolito cambro-ordovícico del Cordón de Lila y de la Sierra de Almeida, Región de Antofagasta, Chile

An Upper Cambrian-Ordovician (490-460 Ma) batholith crop out along the Cordón de Lila and Sierra de Almeida, in the Antofagasta region, northern Chile, which belongs to the Famatinian arc. Two plutonic rock types can be distinguished: granodiorites and monzogranites. The first lithology is positioned along an occidental fringe in as much the second is located along an oriental part of the batholith. The main geochemical difference between the two lithologies is the enrichment in silica and K of the second with respect of the first one. Most of the granodiorites are metaluminous or are located between the metaluminous and peraluminous fields. The monzogranites are mostly peraluminous. The chemical composition of the plutons (mayor and trace elements and rare earth elements) allow to infer a common origin for both groups, from a mafic magma that evolved by fractional crystallization. The difference in composition between both lithologies, specially the meta or peraluminous character, can be explained by means a different degree of interaction of the original magma with the felsic crustal rocks.

Exploiting end-of-life lamps fluorescent powder e-waste as a secondary resource for critical rare earth metals

The consensus is growing for the UN sustainable development goals regarding responsible consumption, production, and climate actions. Because of growth towards a digital society (“industry 4.0 revolution”), it is needed to have our resources and economies to be circular. The success also depends on appropriate management of critical raw materials, such as Rare Earth Elements (REEs). Here, a cost-effective recycling method for the recovery of single REEs from fluorescent powder (FP) with end-of-life lamp e-waste is presented with the additional benefit of having a much less environmental impact than mining. The recycling method involves a carefully designed sequential digestion of two phosphor components (YOX and LAP) and treating their leachates separately under specific hydrometallurgical conditions. The phosphors were targeted for Yttrium (Y), Europium (Eu), Terbium (Tb), Lanthanum (La), Cerium (Ce), and Gadolinium (Gd). On trace REEs basis, the leaching process with the FP showed >95% recovery for Eu, La, Ce, Y and Tb. The effective recycling was achieved to >99% purity for Y, Eu, and Tb in 1, 25, and 55 liquid-liquid extraction stages, respectively. To our knowledge, this is one of the first methods to leach and separate Tb from FP e-waste with near quantitative leaching efficiency and >99% purity.

Microbiomes in a manganese oxide producing ecosystem in the Ytterby mine, Sweden: impact on metal mobility.

ABSTRACTMicrobe-mediated precipitation of Mn-oxides enriched in rare earth elements (REE) and other trace elements was discovered in tunnels leading to the main shaft of the Ytterby mine, Sweden. Defining the spatial distribution of microorganisms and elements in this ecosystem provide a better understanding of specific niches and parameters driving the emergence of these communities and associated mineral precipitates. Along with elemental analyses, high-throughput sequencing of the following four subsystems were conducted: (i) water seeping from a rock fracture into the tunnel, (ii) Mn-oxides and associated biofilm; referred to as the Ytterby Black Substance (YBS) biofilm (iii) biofilm forming bubbles on the Mn-oxides; referred to as the bubble biofilm and (iv) fracture water that has passed through the biofilms. Each subsystem hosts a specific collection of microorganisms. Differentially abundant bacteria in the YBS biofilm were identified within the Rhizobiales (e.g. Pedomicrobium), PLTA13 Gammaproteobacteria, Pirellulaceae, Hyphomonadaceae, Blastocatellia and Nitrospira. These taxa, likely driving the Mn-oxide production, were not detected in the fracture water. This biofilm binds Mn, REE and other trace elements in an efficient, dynamic process, as indicated by substantial depletion of these metals from the fracture water as it passes through the Mn deposit zone. Microbe-mediated oxidation of Mn(II) and formation of Mn(III/IV)-oxides can thus have considerable local environmental impact by removing metals from aquatic environments.