A spectral approach on mineralogy and geochemistry of garnet skarns in Arc-Type granitoids

Şaşmaz, Ahmet; Kiliç, Ayşe; Akgül, Bunyamin

doi:10.1016/j.saa.2022.122037

Cited by 8 publications

(12 citation statements)

References 38 publications

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“…Ilmenite exsolves into hematite lamellae during solid-state oxidation and cooling. Skarn deposits occur in the contact zones between the Pertek granitoid (the Elazığ magmatite) and the Keban metamorphites [42,53]. The formation of ore bodies associated with granitic intrusion is controlled by the thrust-nappe fault.…”

Section: Geological Settingmentioning

confidence: 99%

“…In the prograde anhydrous The stages of skarnization were distinguished by observing the mineral assemblages, textures, and zoning patterns within the skarn deposits, alongside the study of the fluid inclusions and stable isotope compositions (Figures 2 and 3). Additionally, laboratory experiments and thermodynamic modeling can provide insights into the conditions under which these mineral reactions occurred during the prograde and retrograde stages of skarnization [42,61]. The presence of anhydrous minerals such as andradite and diopside indicated the prograde stage, while the occurrence of hydrous minerals such as epidote indicated subsequent retrograde development.…”

Section: Mineralizationmentioning

confidence: 99%

“…In the retrograde stage, garnets covered with fluorite, quartz, calcite and sulfide minerals were accompanied by hematite, magnetite, epidote, sulfides and calcites (Figure 3). From the fluid inclusions in the retrograde sulfide veins, it can be stated that the homogenization temperature was 125-255 • C and the salinity was equivalent to 0.2-6.2 wt% NaCl [42,59]. The cracks in the garnet in the BSE and microscope images may have been related to hydrocracking following the boiling process [64] (Figure 4).…”

Section: Mineralizationmentioning

confidence: 99%

“…Gu et al [37] described and classified multiple genetic skarns as metasomatic skarns, skarns formed via regional metamorphism and migmatization, and skarns affected by volcanic hydrothermal solutions. Skarn formation has been explained via factors such as the bimetasomatic reactions between lithologies of different origins, the metamorphic recrystallization of impure carbonate rocks, and infiltration metasomatism involving hydrothermal fluids of magmatic origin [38][39][40][41][42][43]. Most large skarn deposits are associated with magmatic-hydrothermal systems [43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

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Garnet Geochemistry of Pertek Skarns (Tunceli, Turkey) and U-Pb Age Findings

Kilic,

Konakci,

Sasmaz

2024

Minerals

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The Fe skarn and vein-type Cu mineralization types are common in the Eastern Taurus Mountains. This study aims to determine the U-Pb geochronology of garnets of varying sizes within the skarn zone developed at the quartz diorite–marble contact zone in Ayazpınar, Pertek District, Tunceli Province, Turkey. Additionally, this study aims to determine the age of the skarnization and the types of inclusion minerals in the garnets. Faulting and magma emplacement along the thrust plane caused mineralization in the Eastern Taurus Mountains, especially at the marble and quartz diorite contact zone between the cities of Elazığ and Tunceli. The greenish garnets found in the Ayazpınar deposit are characteristic of distal skarns, while red or brown Pertek garnets are observed in the proximal skarns. The garnets typically feature a core–rim texture. The cores of the garnet crystals are large, reddish in color, and have a high REE (Ce, Pr) content. Moreover, the cores have higher Fe and lower Al ratios, alongside higher La, Ce, and Pr contents, than the rims. We propose that the compositional differences between the rims and the cores reflect the transition from oxidized REE- and Fe3+-rich liquids to liquids with lower REE and Fe3+ contents, producing the differences in the garnet colors. Green garnets show lower REE contents than brown garnets with Fe-rich cores. The skarn under study includes the following successively formed zones: diorite → epidote skarn → garnet–magnetite → pyrite–garnet–magnetite → calcite carbonate. Diopside, magnetite, and hematite, including small grains, are surrounded or enveloped by garnets. The U-Pb age of the mineralization is 74.1 ± 5 Ma, indicating that the mineralization occurred concurrently with the intrusion settlement.

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Section: Geological Settingmentioning

confidence: 99%

Section: Mineralizationmentioning

confidence: 99%

Section: Mineralizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Garnet Geochemistry of Pertek Skarns (Tunceli, Turkey) and U-Pb Age Findings

Kilic,

Konakci,

Sasmaz

2024

Minerals

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“…REE concentrations in phosphate nodules have been formed as a direct product of ocean chemistry [45,76,101]. As an alternative, it is thought that the extremely high REE concentrations in phosphates are a byproduct of the REEs being redistributed between the authigenic and detrital phases of the phosphate during its diagenetic equilibration with pore water [100][101][102].…”

Section: Source Of Rees In Phosphate Nodulesmentioning

confidence: 99%

Geochemical Evidence of Ediacaran Phosphate Nodules in the Volyno-Podillya-Moldavia Basin, Ukraine

et al. 2023

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The sedimentary basin of Podillya (Volyno-Podillya-Moldavia) is situated in the southwest of the Ukrainian crystalline shield and belongs to the middle part of the Upper Neoproterozoic section of the Moguiliv-Podilska Group. By analyzing the primary oxide, trace, and rare-earth element compositions of the phosphate nodules in the area, this study sought to shed light on the potential precipitation characteristics of the Ediacaran Sea, where phosphate nodules were created. The mean major oxide contents of the nodules were 50.8 wt.% CaO, 34.2 wt.% P2O5, 5.29 wt.% SiO2, 4.77 wt.% LOI, 1.69 wt% Fe2O3, 1.63 wt% Al2O3, and 0.35 wt.% MnO. The average trace element concentrations were 183 ppm Ba, 395 ppm Sr, 13.4 ppm Ni, 32.7 ppm Cr, 62.2 ppm Zn, 764 ppm Y, 16 ppm V, 10.8 ppm As, 75.8 ppm Cu, 84 ppm Pb, 2.1 ppm U, 1.7 ppm Th, and 4.2 ppm Co. The trace element contents were generally low and indicated an assemblage of Cu, Y, As, Cd, and Pb enrichments in comparison to PAAS. The total REE concentrations varied from 1638 ppm to 3602 ppm. The nodules had medium REE (MREE) enrichments and showed similar REE patterns normalized to PAAS. All the nodules had strongly negative Ce, Pr, and Y anomalies and substantially negative Eu anomalies, with four samples being exceptions. These abnormalities suggest that oxic and suboxic sea conditions existed at the time the nodules formed. The extremely high REE concentrations are thought to be the result of REEs being redistributed between the authigenic and detrital phases that were created during the diagenetic equilibration of phosphate with pore water. The genetic hypothesis for phosphate nodule formation states that the nodules were generally formed in oxic and suboxic seawater and were precipitated on slopes in response to a significant upwelling from a deeper basin with abundant organic matter under anoxic/suboxic conditions. The majority of the organic material at the water–sediment interface of the seafloor underwent oxidation before phosphate was released into the pore water of the sediment.

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