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  • 1
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    Li-Co–Ni-Mn-(REE) veins of the Western Erzgebirge, Germany—a potential source of battery raw materials (2021)
    Burisch, Mathias ; Frenzel, Max ; Seibel, Henning ; [weitere]
    Springer Berlin Heidelberg
    Details
    Publikationsdatum: 2023-06-22
    Beschreibung: Situated in the western Erzgebirge metallogenetic province (Vogtland, Germany), the Eichigt prospect is associated with several quartz-Mn-Fe-oxyhydroxide veins that are exposed at surface. Bulk-rock geochemical assays of vein material yield high concentrations of Li (0.6–4.1 kg/t), Co (0.6–14.7 kg/t), and Ni (0.2–2.8 kg/t), as well as significant quantities of Mn, Cu, and light rare earth elements, a very unusual metal tenor closely resembling the mixture of raw materials needed for Li-ion battery production. This study reports on the results of a first detailed investigation of this rather unique polymetallic mineralization style, including detailed petrographic and mineralogical studies complemented by bulk rock geochemistry, electron microprobe analyses, and laser ablation inductively coupled mass spectrometry. The mineralized material comprises an oxide assemblage of goethite hematite, hollandite, and lithiophorite that together cement angular fragments of vein quartz. Lithiophorite is the predominant host of Li (3.6–11.1 kg/t), Co (2.5–54.5 kg/t), and Ni (0.2–8.9 kg/t); Cu is contained in similar amounts in hollandite and lithiophorite whereas light rare earth elements (LREE) are mainly hosted in microcrystalline rhabdophane and florencite, which are finely intergrown with the Mn-Fe-oxyhydroxides. 40Ar/39Ar ages (~ 40–34 Ma) of coronadite group minerals coincide with tectonic activity related to the Cenozoic Eger Graben rifting. A low-temperature hydrothermal overprint of pre-existing base metal sulfide-quartz mineralization on fault structures that were reactivated during continental rifting is proposed as the most likely origin of the polymetallic oxyhydroxide mineralization at Eichigt. However, tectonically enhanced deep-reaching fracture-controlled supergene weathering cannot be completely ruled out as the origin of the mineralization.
    Beschreibung: Lithium Australia
    Beschreibung: European Social Fund http://dx.doi.org/10.13039/501100004895
    Beschreibung: Technische Universität Bergakademie Freiberg (3135)
    Schlagwort(e): ddc:553.4 ; Lithiophorite ; Coronadite group ; Hollandite ; Cryptomelane ; 40Ar/39Ar geochronology ; Trace elements ; Lithium ; Manganese ; Cobalt ; Exploration ; Raw materials
    Sprache: Englisch
    Materialart: doc-type:article
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  • 2
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    Metallic Fluence Monitors and J-value standards (2014)
    PANGAEA
    In:  Supplement to: Rutte, Daniel; Pfänder, Jörg A; Koleška, Michal; Jonckheere, Raymond; Unterricker, Sepp (2015): Radial fast-neutron fluence gradients during rotating 40Ar/39Ar sample irradiation recorded with metallic fluence monitors and geological age standards. Geochemistry, Geophysics, Geosystems, 16(1), 336-345, https://doi.org/10.1002/2014GC005611
    Details
    Publikationsdatum: 2023-01-13
    Beschreibung: Utilizing the neutron-irradiation parameter J is one of the major uncertainties in 40Ar/39Ar dating. The associated error of the individual J-value for a sample of unknown age depends on the accuracy of the age of the geological standards, the fast-neutron fluence distribution in the reactor and the distances between standards and samples during irradiation. While it is generally assumed that rotating irradiation evens out radial neutron fluence gradients, we observed axial and radial variations of the J-values in sample irradiations in the rotating channels of two reactors. To quantify them, we included three-dimensionally distributed metallic fast- (Ni) and thermal- (Co) neutron fluence monitors in three irradiations and geological age standards in three more. Two irradiations were carried out under Cd-shielding in the FRG1 reactor in Geesthacht, Germany, and four without Cd-shielding in the LVR-15 reactor in Řež, Czech Republic. The 58Ni(nf,p)58Co activation reaction and γ-spectrometry of the 811 keV peak associated with the subsequent decay of 58Co to 58Fe allow to calculate the fast-neutron fluence. The fast-neutron fluences at known positions in the irradiation container correlate with the J-values determined by mass-spectrometric 40Ar/39Ar measurements of the geological age standards. Ra-dial neutron fluence gradients are up to 1.8 %/cm in FRG1 and up to 2.2 %/cm in LVR-15; the corre-sponding axial gradients are up to 5.9 and 2.1 %/cm. We conclude that sample rotation might not al-ways suffice to meet the needs of high-precision dating and gradient monitoring can be crucial.
    Materialart: Dataset
    Format: application/zip, 6.3 MBytes
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    DATA PANGAEA
  • 3
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    Multi-system geochronological and isotopic constraints on age and evolution of the Gaoligongshan metamorphic belt and shear zone system in western Yunnan, China (2013)
    Elsevier
    In:  Journal of Asian Earth Sciences, 73 . pp. 218-239.
    Details
    Publikationsdatum: 2018-01-04
    Beschreibung: The Gaoligongshan metamorphic belt, located east of the Eastern Himalayan Syntaxis (EHS) in the Yunnan province, southwestern China, is a compelling region in which to determine temporal constrains on crustal dynamic processes related to the Himalayan orogeny. We applied multi-system geo- and thermochronology (900 °C to 〈50 °C) to orthogneiss and mylonites from a major shear zone in the southern Gaoligongshan in order to elucidate the magmatic, cooling and exhumation history of this belt. Zircon U/Pb data reveal three magmatic events at ∼486 Ma, ∼136 Ma and ∼76 Ma. Similar ages are found in orthoderivative rocks of the neighboring Tengchong and Baoshan blocks, and the Gangdese batholith, suggesting that the southern Gaoligongshan is composed of an assemblage of Lhasa and Qiangtang terrane derived rocks. Muscovite Rb/Sr ages of 35–21 Ma are coeval with the onset of lateral crustal displacement along major shear zones in Eastern Tibet and Indochina, and with the post-collision volcanic activity in western Yunnan. Biotite Rb/Sr and mica 40Ar/39Ar ages provide evidence that mylonitization along the Gaoligongshan shear zone and crustal rotation of the Tengchong and Baoshan blocks proceeded during the Miocene, between 19 and 12 Ma, when the rocks rapidly cooled through the 350–280 °C temperature range. Almost identical 40Ar/39Ar ages reported for the Karakorum–Jiali–Parlung Fault system in Western Tibet suggest that the Gaoligongshan shear zone is the southeastern continuation of this fault, recording the eastward extrusion of Tibet and crustal movement around the EHS. The final stage of exhumation of the Gaoligongshan occurred between 8 and 5 Ma at an average exhumation rate of ∼3 km/Ma as documented by apatite fission-track and apatite (U–Th–Sm)/He data. This rapid exhumation was triggered by crustal root delamination and opening of the Andaman sea. Our results clearly show that the complex tectonothermal evolution of the Gaoligongshan was influenced by Tibetan extrusion and escape tectonics associated with lower crustal flow around the EHS and the southeastward movement of Indochina and back-arc extension in response to Andaman seafloor spreading.
    Materialart: Article , PeerReviewed
    Format: text
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    DOI: 10.1016/j.jseaes.2013.03.031
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  • 4
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    Age and petrogenesis of Ni-Cu-(PGE) sulfide-bearing gabbroic intrusions in the Lausitz Block, northern Bohemian Massif (Germany/Czech Republic) (2023)
    Elsevier
    Details
    Publikationsdatum: 2024-02-07
    Beschreibung: The Lausitz Block, located in the northernmost part of the Bohemian Massif, hosts a large number of dike- to stock-shaped gabbroic intrusions that mainly comprise brown hornblende-poor (Group I; i.e. olivine gabbronorite, olivine gabbro, gabbro and diorite) and subordinately brown hornblende-rich lithologies (Group II; i.e. olivine-hornblende gabbro and hornblende gabbro). Several of these intrusions host small-scaled magmatic Ni-Cu-(PGE) sulfide accumulations. The intrusions are part of an interconnected mafic–(ultramafic) plumbing system that intruded Cadomian granodiorites of Lausitz Block in the Middle to Late Devonian during the early stages of the Variscan Orogeny. The previously inferred Devonian age of the intrusions is refined by biotite Ar-Ar dating that yield ages between 372.2 ± 3.7 Ma and 389.1 ± 3.9 Ma (2σ). Group I and Group II lithologies differ in their mineralogical and geochemical composition. Compared to the Group I lithologies those of Group II are characterized by higher modal contents of primary brown hornblende, Fe-Ti oxides and apatite, by Ti- and Al-enriched clinopyroxene and by lower contents of SiO 2 and increased contents of TiO 2 , P 2 O 5 , LILE, HFSE and LREE. The differences suggest at least two different magmatic series where Group I rocks are linked to tholeiitic basaltic magmas with low to moderate Ti and volatile contents, whereas Group II rocks are derived from Ti- and volatile-enriched moderate-alkaline basaltic magmas. The magmas experienced clinopyroxene fractionation during their crustal ascent and storage, but were only minor affected by crustal contamination (〈 5 %) according to Sr-Nd-Pb isotope systematics. Clinopyroxene and whole-rock trace element compositions suggest that primary magmas of both series are linked to an intraplate setting. REE systematics suggest primary magma contributions from both garnet and spinel peridotite sources. Group II samples bear evidence for higher proportions of garnet peridotite-derived melts, and trace element modelling indicates melting degrees between ~5–20 % for both groups. The proposed intraplate magmatism is might been related to a subduction slab retreat within the framework of the Variscan orogeny, which leads to lithosphere extension and enhanced decompression melting of the mantle beneath the Lausitz Block. Cu/Zr ratios 〈 1 of gabbroic rocks from several intrusions suggest a previous segregation of magmatic sulfides in other sections of the magmatic plumbing system and give rise for a vertical and lateral Ni-Cu exploration potential.
    Materialart: Article , PeerReviewed
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  • 5
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    40Ar/39Ar ages and bulk-rock chemistry of the lower submarine units of the central and western Aleutian Arc (2021)
    Elsevier
    Details
    Publikationsdatum: 2024-02-07
    Beschreibung: Highlights • The revised minimum subduction initiation age for the Aleutian system is 48 Ma. • The evolution of the arc was characterized by three distinct magmatic pulses. • The types of magmas erupted appear to have changed during the arc evolution. In order to further constrain the timing of the Aleutian Arc initiation as well as its early evolution, an extensive 40Ar/39Ar dating and geochemical (major and selected trace elements) campaign (40 samples) of the lower units of the Aleutian ridge has been carried out on samples dredged from deep fore-arc canyons and rear arc tectonic structures. The new dataset slightly increases the minimum inception age for the Aleutian system, with the two oldest samples dated at 46.1 ± 3.3 Ma and 47.80 ± 0.57 Ma. Both mid Eocene ages were obtained on tholeiitic mafic volcanic rocks from the western section of the arc. The new data also support the occurrence of three distinct periods of enhanced magmatic activity (magmatic pulses) during the pre-Quaternary evolution of the arc (at 38–27, 16–11 and 6–0 Ma), as previously suggested based on a more limited and dominantly subaerial dataset. Moreover, the data refine the duration of the first pulse of activity, which ended 2 Ma later than previous estimates. The first and last pulses may be associated with rotations of the subducting plates while the second pulse might result from regional tectonic changes. The significant overlap between the age distribution of the submarine and subaerial samples suggests that much of the earlier parts of the arc may have been uplifted and subaerially exposed. The expected crustal growth associated with the pulses is unlikely to have significantly impacted magmatic residence times, since no variation in the degree of differentiation of the rocks can be observed during or after the pulses. On the other hand, the type of magmas erupted may have changed during the arc evolution. Prior to the first pulse, activity appears to have been dominantly tholeiitic. On the other hand, the first pulse was characterized by coeval tholeiitic, transitional and calc-alkaline magmas, with calc-alkaline activity increasing after the first ~3 Ma. Subsequently, a dominantly calc-alkaline period occurred from 29 to 8 Ma, followed by a progressive return of coeval tholeiitic, transitional and calc-alkaline activity. These temporal changes in magma types correspond to likely variations in arc crustal thickness beneath the active front, and could therefore be a response to physical changes of the overriding plate.
    Materialart: Article , PeerReviewed
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  • 6
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    Late-Pleistocene rejuvenated volcanism and flank collapse deposits on a Cretaceous seamount near El Hierro, Canary Archipelago (2024)
    Elsevier
    Details
    Publikationsdatum: 2024-05-17
    Materialart: Article , PeerReviewed , info:eu-repo/semantics/article
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