Eynatten, Hilmar von

[["dc.bibliographiccitation.firstpage","581"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Contributions to Mineralogy and Petrology"],["dc.bibliographiccitation.lastpage","596"],["dc.bibliographiccitation.volume","161"],["dc.contributor.author","Triebold, Silke"],["dc.contributor.author","Luvizotto, George Luiz"],["dc.contributor.author","Tolosana-Delgado, Raimon"],["dc.contributor.author","Zack, Thomas"],["dc.contributor.author","von Eynatten, Hilmar"],["dc.date.accessioned","2018-11-07T08:57:54Z"],["dc.date.available","2018-11-07T08:57:54Z"],["dc.date.issued","2011"],["dc.description.abstract","Investigation by Raman spectroscopy of samples from different geological settings shows that the occurrence of TiO2 polymorphs other than rutile can hardly be predicted, and furthermore, the occurrence of anatase is more widespread than previously thought. Metamorphic pressure and temperature, together with whole rock chemistry, control the occurrence of anatase, whereas variation of mineral assemblage characteristics and/or fluid occurrence or composition takes influence on anatase trace element characteristics and re-equilibration of relict rutiles. Evaluation of trace element contents obtained by electron microprobe in anatase, brookite, and rutile shows that these vary significantly between the three TiO2 phases. Therefore, on the one hand, an appropriation to source rock type according to Nb and Cr contents, but as well application of thermometry on the basis of Zr contents, would lead to erroneous results if no phase specification is done beforehand. For the elements Cr, V, Fe, and Nb, variation between the polymorphs is systematic and can be used for discrimination on the basis of a linear discriminant analysis. Using phase group means and coefficients of linear discriminants obtained from a compilation of analyses from samples with well-defined phase information together with prior probabilities of groupings from a natural sample compilation, one is able to calculate phase grouping probabilities of any TiO2 analysis containing at least the critical elements Cr, V, Fe, and Nb. An application of this calculation shows that for the appropriation to the phase rutile, a correct-classification rate of 99.5% is obtained. Hence, phase specification by trace elements proves to be a valuable tool besides Raman spectroscopy."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft [EY 23/10-2, ZA 285/2-1]"],["dc.identifier.doi","10.1007/s00410-010-0551-x"],["dc.identifier.isi","000288169900005"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/6618"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/23514"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.relation.issn","0010-7999"],["dc.relation.orgunit","Fakultät für Geowissenschaften und Geographie"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Discrimination of TiO2 polymorphs in sedimentary and metamorphic rocks"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","233"],["dc.bibliographiccitation.issue","3-4"],["dc.bibliographiccitation.journal","Mineralogy and Petrology"],["dc.bibliographiccitation.lastpage","249"],["dc.bibliographiccitation.volume","97"],["dc.contributor.author","Luvizotto, George Luiz"],["dc.contributor.author","Zack, Thomas"],["dc.contributor.author","Triebold, Silke"],["dc.contributor.author","von Eynatten, Hilmar"],["dc.date.accessioned","2018-11-07T11:21:39Z"],["dc.date.available","2018-11-07T11:21:39Z"],["dc.date.issued","2009"],["dc.description.abstract","Metamorphic textures in medium-grade (similar to 500-550A degrees C) metasedimentary rocks from the Erzgebirge give evidence of prograde rutile crystallization from ilmenite. Newly-crystallized grains occur as rutile-rich polycrystalline aggregates that pseudomorph the shape of the ilmenites. In-situ trace element data (EMP and SIMS) show that rutiles from the higher-grade samples record large scatter in Nb content and have Nb/Ti ratios higher than coexisting ilmenite. This behavior can be predicted using prograde rutile crystallization from ilmenite and indicates that rutiles are reequilibrating their chemistry with remaining ilmenites. On the contrary, rutiles from the lowest grade samples (similar to 480A degrees C) have Nb/Ti ratios that are similar to the ones in ilmenite. Hence, rutiles from these samples did not equilibrate their chemistry with remaining ilmenites. Our data suggest that temperature may be one of the main factors determining whether or not the elements are able to diffuse between the phases and, therefore, reequilibrate. Newly-crystallized rutiles yield temperatures (from similar to 500 to 630A degrees C, Zr-in-rutile thermometry) that are in agreement with the metamorphic conditions previously determined for the studied rocks. In quartzites from the medium-grade domain (similar to 530A degrees C), inherited detrital rutile grains are detected. They are identified by their distinct chemical composition (high Zr and Nb contents) and textures (single grains surrounded by fine grained ilmenites). Preliminary calculation, based on grain size distribution of rutile in medium-grade metapelites and quartzites that occur in the studied area, show that rutiles derived from quartzites can be anticipated to dominate the detrital rutile population, even if quartzites are a minor component of the exposure."],["dc.identifier.doi","10.1007/s00710-009-0092-z"],["dc.identifier.isi","000272177900007"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/11208"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55823"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","Wien"],["dc.relation.issn","0930-0708"],["dc.relation.orgunit","Fakultät für Geowissenschaften und Geographie"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Rutile occurrence and trace element behavior in medium-grade metasedimentary rocks: example from the Erzgebirge, Germany"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]