Fossilized Bacteria in Fe-Mn-Mineralization: Evidence from the Legrena Valley, W. Lavrion Mine (Greece)

Vasilatos, Charalampos; Economou-Eliopoulos, Maria

doi:10.3390/min8030107

Cited by 8 publications

(3 citation statements)

References 37 publications

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“…The mineral chemistry of the accessory phases was determined through Energy Dispersive Spectroscopy (EDS) analyses at the Department of Geology and Geoenvironment, using a JEOL JSM 5600 SEM. An Oxford X ISIS 300 detector was employed, and the analytical conditions included a 20 kV accelerating beam voltage, a beam diameter of less than 2 µm, and a count time of 50 s. Calibration prior to analysis was performed using the same procedure and standards as described in [60]. For the measurements of P, La, Ce, Th, U and Zr, the standards used for calibration were GaP, LaB 6 , CeO 2 , ThO 2 , U (metal) and Zr (metal), respectively.…”

Section: Methodsmentioning

confidence: 99%

The REE-Zr-U-Th Minerals of the Maronia Monzodiorite, N. Greece: Implications on the Saturation and Segregation Mechanisms of Critical Metals in Intermediate–Mafic Compositions

Vasilatos,

Papoutsa

2023

Minerals

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This work delves into the presence of REE-Ti-Zr-U-Th minerals, in the mafic–intermediate rocks of the Maronia pluton, Greece, an Oligocene intrusion formed through arc-magmatism during subduction. In Maronia monzodiorite, critical metals are contained in three principal mineral groups, namely, the REE-Ti-Zr, REE-Ca-P, and U-Th assemblages. The REE-Ti-Zr group includes REE-ilmenite, chevkinite-like phases, zirconolite, and baddeleyite. The REE-Ca-P assemblage is represented by allanite-(Ce), monazite-(Ce), and huttonitic monazite-(Ce). The U-Th assemblage comprises thorite–coffinite and uraninite–thorianite solid solutions. The paragenetic sequencing of these minerals offers insights into their formation conditions and correlation with the pluton’s magmatic evolution. In the REE-Ti-Zr group, mineral formation progresses from REE-ilmenite to baddeleyite through chevkinite-like phases and zirconolite under oxidizing conditions. The REE-Ca-P sequence involves allanite-(Ce), followed by monazite-(Ce), late allanite-(Ce), and huttonitic monazite-(Ce). In the U-Th group, earlier thorite–coffinite phases are succeeded by uraninite–thorianite solid solutions, indicating Si-undersaturation at late magmatic stages. Fluctuations in Ca-activity induce alternating formations of allanite-(Ce) and monazite-(Ce). These mineral variations are attributed to early-stage interactions between high-K calc-alkaline and shoshonitic gabbroic melts, influencing critical metal enrichment and mineral speciation. The study’s insights into paragenesis and geological processes offer implications for mineral exploration in analogous geological settings.

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Section: Methodsmentioning

confidence: 99%

The REE-Zr-U-Th Minerals of the Maronia Monzodiorite, N. Greece: Implications on the Saturation and Segregation Mechanisms of Critical Metals in Intermediate–Mafic Compositions

Vasilatos,

Papoutsa

2023

Minerals

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“…Fe-Mn mineralization in Lavreotiki area is generally hosted within carbonate rocks, close to the surface of the detachment faults and the contacts between lower and upper marbles with the Kessariani schist. The characteristic features of that type of Fe-Mn mineralization seems to be the result of multistage supergene processes superimposed over initial hydrothermal stages (Vasilatos and Economou-Eliopoulos, 2018;Vasilatos et al, 2022). The occurrence of abundant bacteriomophic Fe-Mn-oxides/hydroxides in those deposits has been attributed by Vasilatos and Economou-Eliopoulos (2018) and Vasilatos et al (2022) to bacteria-driven redox reactions during those ore-forming processes.…”

Section: Fig 2 Georeferenced (Projection Utm34 -Wgs84mentioning

confidence: 99%

“…The characteristic features of that type of Fe-Mn mineralization seems to be the result of multistage supergene processes superimposed over initial hydrothermal stages (Vasilatos and Economou-Eliopoulos, 2018;Vasilatos et al, 2022). The occurrence of abundant bacteriomophic Fe-Mn-oxides/hydroxides in those deposits has been attributed by Vasilatos and Economou-Eliopoulos (2018) and Vasilatos et al (2022) to bacteria-driven redox reactions during those ore-forming processes. However, typical iron-rich gossan formations are located at, or close to, the surface of the detachment fault.…”

Section: Fig 2 Georeferenced (Projection Utm34 -Wgs84mentioning

confidence: 99%

Investigating the capability of Sentinel-2 and Worldview-3 VNIR satellite data to detect mineralized zones at an igneous intrusion in the Koutala islet (Lavreotiki, Greece) using laboratory mineralogical analysis, reflectance spectroscopy and spectral indices

et al. 2023

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During the last decades, the rapid progress of remote sensing data processing for their utilization in detecting locations of possible sites linked to hydrothermal alteration and ores has gained increasing attention due to significant time and cost savings. In this study, we present the findings of a joint remote sensing and laboratory examination of a mineralization zone induced by a granitoid intrusion onshore the islet of “Koutala”, in Lavreotiki, central Greece. Our objective is to investigate the potential of Sentinel-2 and WorldView-3 VNIR satellite data to detect and map oxidized ore zones and alteration minerals that are detected from laboratory analysis of samples and could be linked to Fe-Mn mineralization. Two approaches are followed, namely reflectance spectroscopy and spectral indices. In reflectance spectroscopy, the spectral signatures of all minerals detected in the study area are retrieved from spectral libraries. The signatures are resampled to Sentinel-2 and to WorldView-3 VNIR spectral bands. Continuum-removal is then applied and the diagnostic absorption features of each mineral are detected for each spectral band configuration. The dataset with the best spectral configuration for mineral detection is then used for the production of mineral maps using the corresponding satellite image. The second approach involves the calculation of spectral indices, namely ferric, ferrous iron and hydroxyl-bearing alteration, on reflectance spectra. The ferric iron index is applied to both satellite datasets while the two other indices require the use of SWIR bands and therefore, they can be only calculated on Sentinel-2 data. All results show that laboratory and satellite data analyses results are consistent and complementary. WorldView-3 VNIR data seem to be sensitive only to the ferric and manganese phase. Sentinel-2 data seem to be capable to detect and map all alteration minerals that are potentially linked to Fe-Mn ore, including both ferric and ferrous phases. The mineral absorption and spectral indices maps show that in the investigated area, there is significant mineralization related to the granitoid intrusion. Hydrothermal alteration is observed on the entire surface of the islet but it seems to be stronger at the eastern part of the islet where the granitoid/schist contact is located. It is the first time that (i) minerals linked to a potential Fe-Mn ore are detected on the islet and (b) the corresponding alteration mineral maps are produced from satellite data, revealing their spatial distribution and providing indirect estimations of the degree of their presence.

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Synthetic consortia of four strains promote Schisandra chinensis growth by regulating soil microbial community and improving soil fertility

Li,

Ding,

et al. 2024

Planta

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Fossilized Bacteria in Fe-Mn-Mineralization: Evidence from the Legrena Valley, W. Lavrion Mine (Greece)

Cited by 8 publications

References 37 publications

The REE-Zr-U-Th Minerals of the Maronia Monzodiorite, N. Greece: Implications on the Saturation and Segregation Mechanisms of Critical Metals in Intermediate–Mafic Compositions

The REE-Zr-U-Th Minerals of the Maronia Monzodiorite, N. Greece: Implications on the Saturation and Segregation Mechanisms of Critical Metals in Intermediate–Mafic Compositions

Investigating the capability of Sentinel-2 and Worldview-3 VNIR satellite data to detect mineralized zones at an igneous intrusion in the Koutala islet (Lavreotiki, Greece) using laboratory mineralogical analysis, reflectance spectroscopy and spectral indices

Synthetic consortia of four strains promote Schisandra chinensis growth by regulating soil microbial community and improving soil fertility

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