Unravelling the origin of placer gold: A case study on the largest Roman gold mining sector of NW Spain (Jamuz, León)

2021 ◽  
Author(s):  
Javier Fernández-Lozano ◽  
José María Esbrí ◽  
Ignacio Garrido ◽  
Rosa María Carrasco ◽  
Javier Pedraza ◽  
...  
Keyword(s):  
Colloidal Particles ◽  
Mineral Exploration ◽  
Soil Formation ◽  
Mineral Resources ◽  
Intrinsic Factors ◽  
Complex Processes ◽  
Duero Basin ◽  
Complex Process ◽  
Secondary Formation ◽  
Placer Deposits

<p>NW Iberia hosts a substantial number of mineral resources. Among them, gold (Au) acquired particular relevance since Antiquity, representing one of the largest Roman Au mining provinces in Europe. While primary deposits associated with orogenic Au have been widely studied in the past years, the Plio-Quaternary <em>Raña </em>Au-bearing placer deposits of the western Duero Basin have received little attention. Besides, the different morphology of Au particles suggests complex processes that may have been responsible for the secondary formation of colloidal particles and Au growth grains from complex geochemical soil interactions and biological activity. In this context, exploring the mechanism by means these secondary deposits developed may contribute to understanding the source of Au (extrinsic or intrinsic factors that rule in within <em>Raña </em>deposits) and the formation of potential mineral exploration sectors. This paper outlines the geochemical analysis of a Cenozoic <em>Raña</em>-like deposit in the Jamuz valley (León), where the source of Au and the main characteristics are established. The correlation matrix showed notable relationships between Au, Fe, Na, K, Ca, Pb and As, among the most important. High values in Fe and As provides direct evidence of Au precipitation. Likewise, a non-linear correlation was found between Au-Na, and Au-Ca, suggesting a direct link to soil formation processes. Finally, the presence of apparent differences in grain roundness and the particles' characteristics ranging from monomineral angular Au to polymineral rounded-shaped particles points towards a complex process affecting the <em>Raña </em>deposits. The ubiquitous rubefaction and top-bottom leaching activity produced during rainwater percolation aided by the extreme drainage affecting this conglomeratic formation have often been argued to be responsible for the transformation of mineral phases in soils. The presence of secondary silicification processes and pH drop due to biological reactions (i.e., presence of P) may have been a triggering mechanism for digestion and reprecipitation of Au colloids in these sediments. Our results have outstanding implications on the mechanisms that may determine the Au enrichment of certain levels within the <em>Raña </em>deposits of the western Duero Basin.</p><p>This work was funded by the wine company “Fuentes del Silencio”.</p>

scholarly journals The origin of the galaxy color bimodality

2014 ◽  
Vol 11 (S308) ◽  
pp. 383-389
Author(s):  
M. A. Aragón-Calvo ◽  
Mark C. Neyrinck ◽  
Joseph Silk
Keyword(s):  
Spatial Configuration ◽  
Star Formation History ◽  
Star Forming ◽  
Complex Processes ◽  
Complex Process ◽  
Formation History ◽  
Density Relation ◽  
The Galaxy ◽  
Color Density ◽  
History Of

AbstractThe star formation history of galaxies is a complex process usually considered to be stochastic in nature, for which we can only give average descriptions such as the color-density relation. In this work we follow star-forming gas particles in a hydrodynamical N-body simulation back in time in order to study their initial spatial configuration. By keeping record of the time when a gas particle started forming stars we can produce Lagrangian gas-star isochrone surfaces delineating the surfaces of accreting gas that begin producing stars at different times. These surfaces form a complex a network of filaments in Eulerian space from which galaxies accrete cold gas. Lagrangian accretion surfaces are closely packed inside dense regions, intersecting each other, and as a result galaxies inside proto-clusters stop accreting gas early, naturally explaining the color dependence on density. The process described here has a purely gravitational / geometrical origin, arguably operating at a more fundamental level than complex processes such as AGN and supernovae, and providing a conceptual origin for the color-density relation.

scholarly journals Use of waggle dance information in honey bees is linked to gene expression in the antennae, but not in the brain

2020 ◽  
Author(s):  
Anissa Kennedy ◽  
Tianfei Peng ◽  
Simone M. Glaser ◽  
Melissa Linn ◽  
Susanne Foitzik ◽  
...  
Keyword(s):  
Gene Expression ◽  
Information Integration ◽  
Private Information ◽  
Honey Bees ◽  
Social Information ◽  
Waggle Dance ◽  
Food Sources ◽  
Intrinsic Factors ◽  
Complex Process ◽  
Prior Experiences

AbstractCommunication is essential for social animals, but deciding how to utilize information provided by conspecifics is a complex process that depends on environmental and intrinsic factors. Honey bees use a unique form of communication, the waggle dance, to inform nestmates about the location of food sources. However, as in many other animals, experienced individuals often ignore this social information and prefer to rely on prior experiences, i.e. private information. The neurosensory factors that drive the decision to use social information are not yet understood. Here we test whether the decision to use social dance information or private information is linked to gene expression differences in different parts of the nervous system. We trained bees to collect food from sugar water feeders and observed whether they utilize social or private information when exposed to dances for a new food source. We performed transcriptome analysis of four brain parts critical for cognition: the subesophageal ganglion, the central brain, the mushroom bodies, and the antennal lobes but, unexpectedly, detected no differences between social or private information users. In contrast, we found 413 differentially expressed genes in the antennae, suggesting that variation in sensory perception mediate the decision to use social information. Social information users were characterized by the upregulation of dopamine and serotonin genes while private information users upregualted several genes coding for odor perception. These results highlight that decision making in honey bees might also depend on peripheral processes of perception rather than higher-order brain centers of information integration.

scholarly journals Myeloma as a model for the process of metastasis: implications for therapy

Blood ◽  
2012 ◽  
Vol 120 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Irene M. Ghobrial
Keyword(s):  
Therapeutic Agents ◽  
Plasma Cell Dyscrasia ◽  
Cell Trafficking ◽  
Hematopoietic Stem ◽  
Intrinsic Factors ◽  
Tumor Invasiveness ◽  
Complex Process ◽  
Cell Metastasis ◽  
Multistep Process ◽  
Cell Dissemination

Abstract Multiple myeloma (MM) is a plasma cell dyscrasia characterized by the presence of multiple myelomatous “omas” throughout the skeleton, indicating that there is continuous trafficking of tumor cells to multiple areas in the bone marrow niches. MM may therefore represent one of the best models to study cell trafficking or cell metastasis. The process of cell metastasis is described as a multistep process, the invasion-metastasis cascade. This involves cell invasion, intravasation into nearby blood vessels, passage into the circulation, followed by homing into predetermined distant tissues, the formation of new foci of micrometastases, and finally the growth of micrometastasis into macroscopic tumors. This review discusses the significant advances that have been discovered in the complex process of invasion-metastasis in epithelial carcinomas and cell trafficking in hematopoietic stem cells and how this process relates to progression in MM. This progression is mediated by clonal intrinsic factors that mediate tumor invasiveness as well as factors present in the tumor microenvironment that are permissive to oncogenic proliferation. Therapeutic agents that target the different steps of cell dissemination and progression are discussed. Despite the significant advances in the treatment of MM, better therapeutic agents that target this metastatic cascade are urgently needed.

SIT4ME project: Up-scaling seismic methods for mineral exploration in the Zinkgruvan mining area, Sweden

2020 ◽  
Author(s):  
Alba Gil ◽  
Alireza Malehmir ◽  
Stefan Buske ◽  
Juan Alcalde ◽  
Puy Ayarza ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Raw Materials ◽  
Imaging Techniques ◽  
Mineral Exploration ◽  
Mineral Resources ◽  
Modern Society ◽  
Careful Analysis ◽  
Mining Area ◽  
Massive Sulphide ◽  
Up Scaling

<p>Mineral resources are used in large quantities than ever before because they are fundamental to our modern society. To this front and facing an up-scaling challenge, the EIT Raw-Materials funded project SIT4ME (Seismic Imaging Techniques for Mineral Exploration) was launched involving several European institutions. As part of the project, a dense multi-method seismic dataset was acquired in the Zinkgruvan mining area at the Bergslagen mineral district of Sweden, which hosts one of the largest volcanic-hosted massive sulphide (VMS) deposits in the country.</p><p>In November 2018, a dense multi-method seismic dataset was acquired in the Zinkgruvan mining area, in a joint collaborative approach among Swedish, Spanish and German partners. A combination of sparse 3D grid and dense 2D profiles in an area of approximately 6 km<sup>2 </sup>was acquired using a 32t seismic vibrator (10-150 Hz) of TU Bergakademie Freiberg, enabling reasonable pseudo-3D sub-surface illumination. For the data acquisition, a total of approximately 1300 receiver positions (10-20 m apart), using different recorders, and 950 source positions were surveyed. All receivers were active during the data acquisition allowing a combination of 2D and semi-3D data to be obtained for various imaging and comparative studies. The main objective of the study, apart from its commercial-realization approach, was also to provide information useful for deep-targeting and structural imaging in this complex geological setting. The main massive-sulphide bearing horizon, Zinkgruvan formation, is strongly reflective as correlated with the existing boreholes in the mine. Careful analysis of the seismic sections suggests a dominant northeast-dipping structure, consistent with the general plunge of the main Zinkgruvan fold that has been suggested in the area.</p><p>Acknowledgements: EIT-RawMaterials is gratefully thanked for funding this up-scaling project 17024.</p>

scholarly journals Application of the Fine-Grained Soil Prospecting Method in Typical Covered Terrains of Northern China

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1383
Author(s):  
Hanliang Liu ◽  
Bimin Zhang ◽  
Xueqiu Wang ◽  
Zhixuan Han ◽  
Baoyun Zhang ◽  
...  
Keyword(s):  
Mineral Exploration ◽  
Mineral Resources ◽  
Northern China ◽  
Gobi Desert ◽  
Test Results ◽  
Fine Grained ◽  
Ore Body ◽  
Ore Bodies ◽  
Fine Grained Soil ◽  
Body Location

In recent years, mineral resources near the surface are becoming scarce, causing focused mineral exploration on concealed deposits in covered terrains. In northern China, covered terrains are widespread and conceal bedrock sequences and mineralization. These represent geochemical challenges for mineral exploration in China. As a deep-penetrating geochemical technology that can reflect the information of deep anomalies, the fine-grained soil prospecting method has achieved ideal test results in arid Gobi Desert covered terrain, semi-arid grassland covered terrain, and alluvium soil covered terrain of northern China. The anomaly range indicated by the fine-grained soil prospecting method is very good with the known ore body location. The corresponding relationship can effectively indicate deep ore bodies and delineate anomalies in unknown areas. Overall, the fine-grained soil prospecting method can be applied to geochemical prospecting and exploration in covered terrains.

scholarly journals Specificity of H2O2 signaling in leaf senescence: is the ratio of H2O2 contents in different cellular compartments sensed in Arabidopsis plants?

2022 ◽  
Vol 27 (1) ◽  
Author(s):  
Ulrike Zentgraf ◽  
Ana Gabriela Andrade-Galan ◽  
Stefan Bieker
Keyword(s):  
Hydrogen Peroxide ◽  
Leaf Senescence ◽  
Mineral Resources ◽  
Stress Signaling ◽  
Oxygen Species ◽  
Differential Impact ◽  
Environmental Signals ◽  
Complex Process ◽  
Cellular Compartments

AbstractLeaf senescence is an integral part of plant development and is driven by endogenous cues such as leaf or plant age. Developmental senescence aims to maximize the usage of carbon, nitrogen and mineral resources for growth and/or for the sake of the next generation. This requires efficient reallocation of the resources out of the senescing tissue into developing parts of the plant such as new leaves, fruits and seeds. However, premature senescence can be induced by severe and long-lasting biotic or abiotic stress conditions. It serves as an exit strategy to guarantee offspring in an unfavorable environment but is often combined with a trade-off in seed number and quality. In order to coordinate the very complex process of developmental senescence with environmental signals, highly organized networks and regulatory cues have to be in place. Reactive oxygen species, especially hydrogen peroxide (H2O2), are involved in senescence as well as in stress signaling. Here, we want to summarize the role of H2O2 as a signaling molecule in leaf senescence and shed more light on how specificity in signaling might be achieved. Altered hydrogen peroxide contents in specific compartments revealed a differential impact of H2O2 produced in different compartments. Arabidopsis lines with lower H2O2 levels in chloroplasts and cytoplasm point to the possibility that not the actual contents but the ratio between the two different compartments is sensed by the plant cells.

scholarly journals Probabilistic assessment of the role of the soil degradation main factors in Kuban rice fields

2020 ◽  
Vol 175 ◽  
pp. 09011
Author(s):  
Tatyana Safronova ◽  
Stanislav Vladimirov ◽  
Igor Prikhodko
Keyword(s):  
Soil Quality ◽  
Colloidal Particles ◽  
Irrigation System ◽  
Probability Distributions ◽  
Soil Formation ◽  
Soil Condition ◽  
Point Of View ◽  
Secondary Salinization ◽  
Average Value ◽  
Operational Activities

As a result of reclamation systems for rice cultivation construction, the conditions of genesis and landscapes soil formation were radically violated. This led to the leaching of active humus and calcium, colloidal particles, nutrients from arable layer to underlying horizons, as a result of which there is a tendency to secondary salinization and solonization of soils. The development of the eluvial glue process and physicochemical parameters change of soils causes a change in the morphological soil profile. Currently relevant are preventing land degradation problems, maintaining and restoring soil fertility. In the article, the authors propose to characterize the rice irrigation system functioning mode from probabilistic point of view. They offer to evaluate the consequences of anthropogenic load, considering operational activities by Poisson stream of a certain intensity. This approach allows to consider uncertainty in terms of probability distributions. The function, characterizing soil quality S(t) was introduced. The function S(t) assumed to be monotonously decreasing. The probability R(S) of achieving a certain soil quality was considered. In case of minimum amount of humus Sm the soil is degrading. In these assumptions the average value expression and probability density of particular soil condition onset duration was received.

The morphology, mineralogy, and behavior of u "fine-grained" gold from placer deposits of Alberta: sampling and implications for mineral exploration

1986 ◽  
Vol 23 (11) ◽  
pp. 1662-1672 ◽  
Author(s):  
L. Giusti
Keyword(s):  
Mineral Exploration ◽  
Sampling Procedure ◽  
Stream Sediments ◽  
Shape Factors ◽  
Athabasca River ◽  
Fine Grained ◽  
The North ◽  
Placer Deposits ◽  
Routine Sampling ◽  
And Behavior

The morphology of a large number of gold grains from stream sediments of the North Saskatchewan River and the Athabasca River was studied, together with the partitioning of the placer gold between various size fractions.Two major morphological varieties of gold were observed: (1) flaky, scaly gold, with folded and hammered edges, and with crystals or crystal faces still visible on the surface; and (2) "sandwiched," droplike particles, sometimes toroidal. About 5% of both types of gold were found to be coated with "new," secondary gold.The size of the majority of the gold grains studied varies between 0.500 and 0.010 mm. The most frequent size range in the North Saskatchewan River is 0.125–0.250 mm, whereas in the Athabasca River it is 0.063–0.125 mm. An important fraction of the gold from both rivers is smaller than 0.063 mm.The average Corey shape factor (CSF) of the gravity-recovered gold increases as the particle size decreases, whereas the gold grains lost to the tailings indicate very low average shape factors (i.e., high degree of flattening). This apparent increase in CSF for the smallest fractions recovered when using mechanical techniques is due to the fact that the flaky gold particles are more difficult to recover than the more spherical ones. Moreover, the presence of a gold-rich rim on all the gold grains increases their hydrophobicity.The sampling procedure to be adopted in Alberta and, more generally, in glaciated terrains is discussed. In particular, the use of the −63 μm fraction for routine sampling of stream sediments is suggested.

Metallogenic Features Modeling and Deep Mineral Exploration of Laochang Ore Field in Ge Jiu

2014 ◽  
Vol 1022 ◽  
pp. 7-13
Author(s):  
Zhao Wu ◽  
Jian Ping Chen ◽  
Meng Long Xu
Keyword(s):  
Chemical Elements ◽  
3D Visualization ◽  
Mineral Exploration ◽  
Mineral Resources ◽  
Controlling Factors ◽  
Predicting Model ◽  
Model Method ◽  
Ore Bodies ◽  
Weight Method ◽  
Visualization Technology

By analyzing metallogenic regulation of the deep skarn ore bodies in Laochang ore field,3D metallogenic features model was established with 3D visualization technology. With “the cubic predicting model” method, the major ore-controlling factors in deep include granites, strata, faults and chemical elements abnormal. We delineated prospect area and outlined ten targets through evidence weight method. Calculating the ore-containing probabilities and the quantities of mineral resources ,it realized prediction of mineral resources on quantity, position and probability. It is important for deep mineral exploration of Laochang ore field in Ge jiu.

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