Karius, Volker

[["dc.bibliographiccitation.firstpage","1665"],["dc.bibliographiccitation.issue","7-8"],["dc.bibliographiccitation.journal","Environmental Earth Sciences"],["dc.bibliographiccitation.lastpage","1676"],["dc.bibliographiccitation.volume","63"],["dc.contributor.author","Fischer, Cornelius"],["dc.contributor.author","Kaufhold, Stephan"],["dc.contributor.author","Wedekind, Wanja"],["dc.contributor.author","Dohrmann, Reiner"],["dc.contributor.author","Karius, Volker"],["dc.contributor.author","Siegesmund, Siegfried"],["dc.date.accessioned","2018-11-07T08:54:03Z"],["dc.date.available","2018-11-07T08:54:03Z"],["dc.date.issued","2011"],["dc.description.abstract","Building stones manufactured from contact metamorphic slates (Fruchtschiefer slate) from Theuma (Sachsen, Germany) were investigated for mineralogical alterations as well as for changes in porosity and surface roughness due to weathering. After weathering periods of several years to decades, the originally dark gray-colored slates show pale spots of several centimeters in size at the surface of building stones. The dark-colored and light-colored sections of the slate show no differences in mineralogy. Surface weathering did not result in newly precipitated minerals. It was also found that the observed differences in color are not caused by variations in sedimentary organic carbon concentration or in sulfide/sulfate concentrations. Obtained results instead indicate that dark surface sections may show a thin cover of recent organic matter (OM), e.g., living OM, soot, dirt, etc. Microscopic investigations suggested that this cover was exfoliated at light-colored surface sections. The observed disaggregation of the upper 2 mm of the building block material results in an increase in porosity. Porosity of black (unweathered) slate is < 2 vol.%. Due to weathering, the slate's pores with diameters > 1 mu m show a significant increase in frequency compared to the original pore size distribution. Porosity of weathered rock volumes increased to approx. 8 vol.%. Discolored surface sections show a higher surface roughness (root-mean-square roughness, Rq similar to 1 mu m) compared to dark-colored slate surfaces (Rq similar to 200 nm), both data are for cleavage planes. Preferentially, the discolored surface sections are located close to the edges of cut stones. This and the alteration in porosity, pore size, and surface roughness indicate that color changes of the slate are largely influenced by rock disaggregation proceeding from the edges into the center rather than by mineral dissolution/precipitation processes."],["dc.description.sponsorship","BMBF [03G0719A]; DFG"],["dc.identifier.doi","10.1007/s12665-011-0986-z"],["dc.identifier.isi","000292744300019"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/22575"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1866-6280"],["dc.relation.orgunit","Abteilung Strukturgeologie und Geodynamik"],["dc.title","Weathering of Fruchtschiefer building stones: mineral dissolution or rock disaggregation?"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.subtype","original_ja"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4703"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","The Science of The Total Environment"],["dc.bibliographiccitation.lastpage","4710"],["dc.bibliographiccitation.volume","407"],["dc.contributor.author","Fischer, Cornelius"],["dc.contributor.author","Karius, Volker"],["dc.contributor.author","Luettge, Andreas"],["dc.date.accessioned","2018-11-07T08:27:34Z"],["dc.date.available","2018-11-07T08:27:34Z"],["dc.date.issued","2009"],["dc.description.abstract","Iron oxide encrustations are formed on black slate surfaces during oxidative weathering of iron sulfide and phosphate bearing, organic matter-rich slates. Synchronously, trace elements are released during ongoing weathering. Laser ablation ICP-MS analyses of a weathered and encrusted slate showed that major portions of the V, Cu, As, Mo, Pb, Th. and U reside in the encrustation. Recently a potential relationship between several micrometer to 500 nm surface topography roughness of such encrustations and its uranium concentration was shown. Based on laser scanning microscopy measurements, the present study shows that this interrelation must be expanded to small submicron-sized half-pores with diameters between 100 nm and 500 nm. We demonstrate that the relationship is not limited to topography variations of a single encrustation in the hand-specimen scale. Surface topography and geochemical analyses of iron oxide encrustations from several locations but from the same geochemical environment and with similar weathering history showed that the concentrations of U, P, Cu, and Zn correlate inversely with the surface roughness parameter F This parameter represents the total surface area and is - in this case - a proxy for the root-mean square surface roughness Rq. This study substantiates the environmental importance that micrometer- to submicrometer topography variations of fluid-rock interfaces govern the trapping of trace elements. (c) 2009 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.scitotenv.2009.04.026"],["dc.identifier.isi","000267839200019"],["dc.identifier.pmid","19457545"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/16232"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","0048-9697"],["dc.title","Correlation between sub-micron surface roughness of iron oxide encrustations and trace element concentrations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3250"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Langmuir"],["dc.bibliographiccitation.lastpage","3266"],["dc.bibliographiccitation.volume","24"],["dc.contributor.author","Fischer, Cornelius"],["dc.contributor.author","Karius, Volker"],["dc.contributor.author","Weidler, Peter G."],["dc.contributor.author","Luettge, Andreas"],["dc.date.accessioned","2018-11-07T11:16:42Z"],["dc.date.available","2018-11-07T11:16:42Z"],["dc.date.issued","2008"],["dc.description.abstract","The surface area and roughness of natural iron oxide precipitations were quantified by 3D optical microscopy in order to get information about fluid-rock interface topography in high-permeability zones. Converged surface roughness data of microscale to submicroscale topography show the predominance of macroporous half-pores (> 500 nm) and the occurrence of smaller half-pores (<500 nm) that dominate the BET surface area of iron oxides. A relationship was found between the occurrence of macroporous surface structures (micrometer range) and the uranium content of iron oxide encrustations. Iron-normalized uranium concentrations of an X-ray amorphous iron oxide encrustation correlate linearly with maximum topography heights of 1 to 2 mu m on hand specimen subsamples. Our study shows the potential importance of micrometer- to submicrometer-size surface features, whose environmental impact is often ignored."],["dc.identifier.doi","10.1021/la703221k"],["dc.identifier.isi","000254480500043"],["dc.identifier.pmid","18302429"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/54656"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Chemical Soc"],["dc.relation.issn","0743-7463"],["dc.title","Relationship between micrometer to submicrometer surface roughness and topography variations of natural iron oxides and trace element concentrations"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","355"],["dc.bibliographiccitation.issue","5-6"],["dc.bibliographiccitation.journal","Journal of Sedimentary Research"],["dc.bibliographiccitation.lastpage","365"],["dc.bibliographiccitation.volume","77"],["dc.contributor.author","Fischer, Cornelius"],["dc.contributor.author","Karius, Volker"],["dc.contributor.author","Thiel, Volker"],["dc.date.accessioned","2018-11-07T11:02:51Z"],["dc.date.available","2018-11-07T11:02:51Z"],["dc.date.issued","2007"],["dc.description.abstract","Low-grade metamorphic black slates were examined for the impact of oxidative weathering after exposure to the atmosphere for well-constrained time periods. Measurements of organic carbon were carried out on roofing slates and alum slate mining waste, and were compared against data obtained from freshly mined material. The results show that the organic-carbon content of roofing slates decreased from initially 0.73-1.7 wt.% to 0.51, 0.42, and 0.50 wt.% after 90, 94, and 100 years, respectively. The organic-carbon content of alum slate mining waste decreased from > 7.5 wt.% at the base (5 in below surface) to < 1 wt.% at the top of a dump during an exposure time of 53 years. The thermal maturity of this black slate organic matter is of anthracite stage. The degradation of organic matter is controlled exclusively by its accessibility within the exposed rock. After intense weathering, different black slate types (alum slate, roof slate) show similar amounts (less than 1 wt.%) of a poorly accessible OM fraction. The results demonstrate that oxidative weathering of organic matter in black slates is a fast process. A substantial decrease of organic matter occurs within only some decades to a century, rather than over geological time spans."],["dc.identifier.doi","10.2110/jsr.2007.041"],["dc.identifier.isi","000246987800001"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/51483"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Sepm-soc Sedimentary Geology"],["dc.relation.issn","1527-1404"],["dc.title","Organic matter in black slate shows oxidative degradation within only a few decades"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]