Sosa, Graciela Miriam

[["dc.bibliographiccitation.firstpage","728"],["dc.bibliographiccitation.journal","Ore Geology Reviews"],["dc.bibliographiccitation.lastpage","739"],["dc.bibliographiccitation.volume","102"],["dc.contributor.author","Cabral, Alexandre Raphael"],["dc.contributor.author","van den Kerkhof, Alfons M."],["dc.contributor.author","Sosa, Graciela Miriam"],["dc.contributor.author","Nolte, Nicole"],["dc.contributor.author","Ließmann, Wilfried"],["dc.contributor.author","Lehmann, Bernd"],["dc.date.accessioned","2019-07-24T07:51:07Z"],["dc.date.available","2019-07-24T07:51:07Z"],["dc.date.issued","2018"],["dc.description.abstract","Clausthalite and tiemannite from the type locality, Clausthal, in the Harz Mountains, Germany, have virtually gone undocumented since their discovery in the nineteenth century. The minerals and their selenide assemblages are here documented in historical samples from the Königin Charlotte mine in the former Clausthal Pb–Zn–Ag mining district. Clausthalite and tiemannite are the main selenide components; naumannite is generally subordinate, whereas klockmannite and eskebornite are accessory minerals. The absence of inversion lamellae in naumannite constrains the formation temperature to < 130 °C, a temperature that is compatible with salbands of tiemannite and clausthalite that occur in the wall rock of bleached and reddened greywacke along a calcite–quartz veinlet. The veinlet calcite and quartz trapped highly saline, Ca-rich brines (26–33 wt% NaCl equivalent), at temperatures between 96 and 212 °C. Tiemannite and clausthalite also form massive to semi-massive pockets. Tiemannite hosts inclusions of celestine, anhydrite and carrollite. This inclusion assemblage indicates that tiemannite precipitated from sulfate-bearing brines that likely originated from the overlying Zechstein evaporitic sediments. Such an origin is reflected in the less radiogenic 87Sr/86Sr values of 0.70914 and 0.71133 for two samples of tiemannite aggregates containing celestine–anhydrite inclusions. The Clausthal selenide assemblages postdated the main sulfide-bearing, polymetallic vein-style mineralisation of the Harz Mountains."],["dc.identifier.doi","10.1016/j.oregeorev.2018.09.027"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/61968"],["dc.language.iso","en"],["dc.relation.issn","0169-1368"],["dc.title","Clausthalite (PbSe) and tiemannite (HgSe) from the type locality: New observations and implications for metallogenesis in the Harz Mountains, Germany"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.contributor.advisorcorporation","University of San Luis, Argentina"],["dc.contributor.author","Sosa, Graciela Miriam"],["dc.date.accessioned","2019-07-24T08:06:58Z"],["dc.date.available","2019-07-24T08:06:58Z"],["dc.date.issued","1988"],["dc.format.extent","184"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/61974"],["dc.publisher.place","San Luis, Argentina"],["dc.title","Tin-bearing pegmatites of the Sierras de San Luis, geology, mineralogy and genesis"],["dc.type","thesis"],["dc.type.internalPublication","no"],["dc.type.subtype","dissertation"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","300"],["dc.bibliographiccitation.journal","Marine and Petroleum Geology"],["dc.bibliographiccitation.lastpage","322"],["dc.bibliographiccitation.volume","77"],["dc.contributor.author","Duschl, Florian"],["dc.contributor.author","van den Kerkhof, Alfons M."],["dc.contributor.author","Sosa, Graciela"],["dc.contributor.author","Leiss, Bernd"],["dc.contributor.author","Wiegand, Bettina A."],["dc.contributor.author","Vollbrecht, Axel"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T10:06:47Z"],["dc.date.available","2018-11-07T10:06:47Z"],["dc.date.issued","2016"],["dc.description.abstract","New petrographic and fluid inclusion data from core samples of Upper Permian dolomitic limestone (Hauptdolomit, Zechstein group, Stassfurt carbonate sequence) from a gas field located at the northern border of the Lower Saxony Basin (LSB) essentially improve the understanding of the basin development. The gas production at the locality is characterized by very high CO2 concentrations of 75-100% (with CH4 and N-2). Samples consist of fine grained, mostly laminated and sometimes brecciated dolomitic limestone (mudstone/wackestone) from the transition zone between the shallow water zone (platform) and the upper slope. The study focuses on migration fluids, entrapped as fluid inclusions in diagenetic anhydrite, calcite, and fluorite, and in syn-diagenetic microfractures, as well as on the geochemistry of fluorite fracture mineralizations, obtained by LA-ICP-MS analysis. Fluid inclusion studies show that the diagenetic fluid was rich in H2O-NaCl-CaCl2. Recrystallized anhydrite contains aqueous inclusions with homogenization temperatures (T-h) of ca. 123 degrees C, but somewhat higher Th of ca. 142 degrees C was found for calcite cement followed by early Fluorite A with Th of 147 degrees C. A later Fluorite B preserves gas inclusions and brines with maximum Th of 156 degrees C. Fluorite B crystallized in fractures during the mobilization of CO2-bearing brines. Crossing isochores for co-genetic aqueous-carbonic and carbonic inclusions indicate fluid trapping conditions of 180-200 degrees C and 900-1000 bars. delta C-13-isotopic ratios of gas trapped in fluid inclusions suggest an organic origin for CH4, while the CO2 is likely of inorganic origin. Basin modelling (1D) shows that the fault block structure of the respective reservoir has experienced an uplift of >1000 m since Late Cretaceous times. The fluid inclusion study allows us to, 1) model the evolution of the LSB and fluid evolution by distinguishing different fluid systems, 2) determine the appearance of CO2 in the geological record and, 3) more accurately estimate burial and uplift events in individual parts of the LSB. (C) 2016 Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","EU [282900]"],["dc.identifier.doi","10.1016/j.marpetgeo.2016.06.020"],["dc.identifier.isi","000384861400020"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39159"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1873-4073"],["dc.relation.issn","0264-8172"],["dc.relation.orgunit","Abteilung Strukturgeologie und Geodynamik"],["dc.title","Fluid inclusion and microfabric studies on Zechstein carbonates (Ca2) and related fracture mineralizations - New insights on gas migration in the Lower Saxony Basin (Germany)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","103079"],["dc.bibliographiccitation.journal","Journal of South American Earth Sciences"],["dc.bibliographiccitation.volume","106"],["dc.contributor.author","Sosa, Graciela"],["dc.contributor.author","van den Kerkhof, Alfons"],["dc.contributor.author","Oyhantçabal, Pedro"],["dc.contributor.author","Wemmer, Klaus"],["dc.contributor.author","Paullier, Felipe"],["dc.contributor.author","Spoturno, Julio Jorge"],["dc.contributor.author","Oriolo, Sebastian"],["dc.date.accessioned","2021-04-14T08:28:54Z"],["dc.date.available","2021-04-14T08:28:54Z"],["dc.date.issued","2021"],["dc.identifier.doi","10.1016/j.jsames.2020.103079"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/82736"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.relation.issn","0895-9811"],["dc.title","Multistage evolution of the Neoproterozoic “El Tarumán” gold vein-type mineralization, Dom Feliciano orogenic belt, Uruguay"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","297"],["dc.bibliographiccitation.journal","Journal of Structural Geology"],["dc.bibliographiccitation.lastpage","303"],["dc.bibliographiccitation.volume","115"],["dc.contributor.author","Sosa, Graciela M."],["dc.contributor.author","Oriolo, Sebastian"],["dc.contributor.author","van den Kerkhof, Alfons"],["dc.date.accessioned","2019-07-24T08:04:04Z"],["dc.date.available","2019-07-24T08:04:04Z"],["dc.date.issued","2018"],["dc.description.abstract","A combined fluid inclusion and microstructural study was carried out in beryl crystals from the San Cayetano Nb-Ta-bearing pegmatite (San Luis, Argentina). Primary aqueous-carbonic fluids (T0) were subsequently re-trapped during shearing, resulting in en-échelon microfractures. The more brittle behaviour of beryl compared to quartz makes this mineral more suitable for the preservation of fluid inclusions and microstructures. The primary inclusions T0 are preserved in strain-free domains, whereas the pseudo-secondary T1-to T3-type inclusions occur in domains showing intracrystalline deformation. CO2 was relatively immobile or reacted to form carbonate in early T1-type inclusions, whereas H2O preferentially migrated along microfractures and was trapped as T2-and T3-type inclusions. Short intragranular trails of fluid inclusions, representing en-échelon healed microfractures, resulted from progressive strain localization. Contrary to previous proposals, this new model implies the progressive thickness reduction of intracrystalline micro-shear zones. Besides, hydrolytic weakening linked to dislocation glide is the most likely mechanism to explain the evolution of fluid inclusions, with intracrystalline deformation enhancing anisotropic diffusion. This study highlights the potential of combined fluid inclusion and microstructural studies in order to understand the interaction between fluid activity and deformation. In this way, valuable insights can be provided into the progressive development of overprinted fabrics and low-to medium-temperature deformation mechanisms of minerals."],["dc.identifier.doi","10.1016/j.jsg.2018.04.005"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/61973"],["dc.language.iso","en"],["dc.relation.issn","0191-8141"],["dc.title","Development of sigmoidal en-échelon microfractures in beryl and the role of strain localization evidenced by fluid inclusions"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","751"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Mineralogical Magazine"],["dc.bibliographiccitation.lastpage","778"],["dc.bibliographiccitation.volume","82"],["dc.contributor.author","van den Kerkhof, Alfons M."],["dc.contributor.author","Sosa, Graciela M."],["dc.contributor.author","Oberthür, Thomas"],["dc.contributor.author","Melcher, Frank"],["dc.contributor.author","Fusswinkel, Tobias"],["dc.contributor.author","Kronz, Andreas"],["dc.contributor.author","Simon, Klaus"],["dc.contributor.author","Dunkl, István"],["dc.date.accessioned","2019-07-24T08:00:05Z"],["dc.date.available","2019-07-24T08:00:05Z"],["dc.date.issued","2018"],["dc.identifier.doi","10.1180/mgm.2018.80"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/61971"],["dc.language.iso","en"],["dc.relation.issn","0026-461X"],["dc.relation.issn","1471-8022"],["dc.title","The hydrothermal Waterberg platinum deposit, Mookgophong (Naboomspruit), South Africa. Part II: Quartz chemistry, fluid inclusions and geochronology"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1172"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","American Mineralogist"],["dc.bibliographiccitation.lastpage","1182"],["dc.bibliographiccitation.volume","106"],["dc.contributor.author","Sosa, Graciela"],["dc.contributor.author","Oriolo, Sebastián"],["dc.contributor.author","van den Kerkhof, Alfons"],["dc.contributor.author","González, Pablo Diego"],["dc.contributor.author","Olaizola, Ezequiel"],["dc.contributor.author","Bechis, Florencia"],["dc.date.accessioned","2021-08-12T07:45:40Z"],["dc.date.available","2021-08-12T07:45:40Z"],["dc.date.issued","2021"],["dc.description.abstract","Abstract Quartz segregations in paragneisses from the Paleozoic basement of the North Patagonian Andes contain highly saline multiphase fluid inclusions with the rare daughter mineral ferropyrosmalite detected by Raman analysis, besides halite, sylvite, hematite, and/or magnetite. During heating experiments, L-V homogenization occurs (256–515 °C), followed by halite dissolution (287–556 °C) and the dissolution of ferropyrosmalite at 550–581 °C. The latter phase transition triggers the growth of clinoamphibole crystals according to the following idealized reactions, written for potential end-members: 4 F e 8 S i 6 O 15 [ ( O H ) 6 C l 4 ] + 6 C a 2 + ( a q ) Ferropyrosmalite ↔ 3 C a 2 F e 5 S i 8 ↔ O 22 ( O H ) 2 + 17 F e 2 + ( a q ) + 16 C l − ( a q ) + 12 O H − + 3 H 2 Ferro-actinolite F e 8 S i 6 O 15 [ ( O H ) 6 C l 4 ] + 2 C a 2 + ( a q ) Ferropyrosmalite + Fe 3 + ( aq ) + 2Al 3 + ( aq ) + Na + ( aq ) + H 2 O ↔ Na C a 2 ( Fe 4 2 + F e 3 + ) ( Al 2 Si 6 ) ↔ O 22 Cl 2 + 4 F e 2 + ( a q ) + 2 C l − ( a q ) + 4 H 2 Chloro-hastingsite Ferropyrosmalite ↔ Chloro-hastingsite The amphibole resembles the composition of ferro-actinolite but also has striking similarities with chloro-hastingsite, as indicated by Raman spectroscopy. During the heating experiment, hematite (when present) transforms to magnetite by the uptake of H2, whereas inclusions without Fe-oxides contain traces of H2 after the reaction. This mineral transformation shows that ferropyrosmalite might result from the retrograde re-equilibration of amphibole with the brine, implying the uptake of Fe2+, Cl–, and H2O and the enrichment of Ca2+ in the brine. Pervasive fluid flow and fluid-assisted diffusion are recorded by channel way microstructures, healed microfractures, and dissolution-reprecipitation phenomena, as demonstrated by cathodoluminescence microscopy. These alkali- and FeCl2-rich brines, derived from magmatic sources and of possible Mesozoic age, were related to regional metasomatism, coeval with widespread granitoid activity."],["dc.description.abstract","Abstract Quartz segregations in paragneisses from the Paleozoic basement of the North Patagonian Andes contain highly saline multiphase fluid inclusions with the rare daughter mineral ferropyrosmalite detected by Raman analysis, besides halite, sylvite, hematite, and/or magnetite. During heating experiments, L-V homogenization occurs (256–515 °C), followed by halite dissolution (287–556 °C) and the dissolution of ferropyrosmalite at 550–581 °C. The latter phase transition triggers the growth of clinoamphibole crystals according to the following idealized reactions, written for potential end-members: 4 F e 8 S i 6 O 15 [ ( O H ) 6 C l 4 ] + 6 C a 2 + ( a q ) Ferropyrosmalite ↔ 3 C a 2 F e 5 S i 8 ↔ O 22 ( O H ) 2 + 17 F e 2 + ( a q ) + 16 C l − ( a q ) + 12 O H − + 3 H 2 Ferro-actinolite F e 8 S i 6 O 15 [ ( O H ) 6 C l 4 ] + 2 C a 2 + ( a q ) Ferropyrosmalite + Fe 3 + ( aq ) + 2Al 3 + ( aq ) + Na + ( aq ) + H 2 O ↔ Na C a 2 ( Fe 4 2 + F e 3 + ) ( Al 2 Si 6 ) ↔ O 22 Cl 2 + 4 F e 2 + ( a q ) + 2 C l − ( a q ) + 4 H 2 Chloro-hastingsite Ferropyrosmalite ↔ Chloro-hastingsite The amphibole resembles the composition of ferro-actinolite but also has striking similarities with chloro-hastingsite, as indicated by Raman spectroscopy. During the heating experiment, hematite (when present) transforms to magnetite by the uptake of H2, whereas inclusions without Fe-oxides contain traces of H2 after the reaction. This mineral transformation shows that ferropyrosmalite might result from the retrograde re-equilibration of amphibole with the brine, implying the uptake of Fe2+, Cl–, and H2O and the enrichment of Ca2+ in the brine. Pervasive fluid flow and fluid-assisted diffusion are recorded by channel way microstructures, healed microfractures, and dissolution-reprecipitation phenomena, as demonstrated by cathodoluminescence microscopy. These alkali- and FeCl2-rich brines, derived from magmatic sources and of possible Mesozoic age, were related to regional metasomatism, coeval with widespread granitoid activity."],["dc.identifier.doi","10.2138/am-2021-7525"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/88524"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-448"],["dc.relation.eissn","1945-3027"],["dc.relation.issn","0003-004X"],["dc.title","Ferropyrosmalite-bearing fluid inclusions in the North Patagonian Andes metasedimentary basement, Argentina: A record of regional metasomatism"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","725"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Mineralogical Magazine"],["dc.bibliographiccitation.lastpage","749"],["dc.bibliographiccitation.volume","82"],["dc.contributor.author","Oberthür, Thomas"],["dc.contributor.author","Melcher, Frank"],["dc.contributor.author","Fusswinkel, Tobias"],["dc.contributor.author","van den Kerkhof, Alfons M."],["dc.contributor.author","Sosa, Graciela M."],["dc.date.accessioned","2019-07-24T08:02:11Z"],["dc.date.available","2019-07-24T08:02:11Z"],["dc.date.issued","2018"],["dc.description.abstract","The Waterberg platinum deposit is an extraordinary example of a vein-type hydrothermal quartz-hematite-PGE (platinum-group element) mineralization. This study concentrates on the geochemical character of the ores and the platinum-group mineral (PGM) assemblage by application of reflected-light and scanning electron microscopy followed by electron probe microanalysis. The PGM-bearing quartz veins show multiple banding indicating numerous pulses of fluid infiltration. Mineralization was introduced contemporaneously with the earliest generation of vein quartz and hematite. High oxygen and low sulfur fugacities of the mineralizing fluids are indicated by hematite as the predominant opaque mineral and the lack of sulfides. The ‘Waterberg type’ mineralization is characterized by unique metal proportions, namely Pt>Pd>Au, interpreted as a fingerprint to the cradle of the metals, namely rocks and ores of the Bushveld Complex, or reflecting metal fractionation during ascent of an oxidized, evolving fluid. The PGM assemblage signifies three main depositional and alteration events. (1) Deposition of native Pt and Pt–Pd alloys (>90% of the PGM assemblage) and Pd–Sb–As compounds (Pt-rich isomertieite and mertieite II) from hydrothermal fluids. (2) Hydrothermal alteration of Pt by Cu-rich fluids and formation of Pt–Cu alloys and hongshiite [PtCu]. (3) Weathering/oxidation of the ores producing Pd/Pt-oxides/hydroxides. Platinum-group element transport was probably by chloride complexes in moderately acidic and strongly oxidizing fluids of relatively low salinity, and depositional temperatures were in the range 400–200°C. Alternatively, quartz and ore textures may hint to noble metal transport in a colloidal formand deposition as gels. The source of the PGE is probably in platiniferous rocks or ores of the Bushveld Complex which were leached by hydrothermal solutions. If so, further Waterberg-type depositsmay be present, and a prime target area would be along the corridor of the Thabazimbi-Murchison-Lineament where geothermal springs are presently still active."],["dc.identifier.doi","10.1180/minmag.2017.081.073"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/61972"],["dc.language.iso","en"],["dc.relation.issn","0026-461X"],["dc.relation.issn","1471-8022"],["dc.title","The hydrothermal Waterberg platinum deposit, Mookgophong (Naboomspruit), South Africa. Part 1: Geochemistry and ore mineralogy"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]