Neuweiler, Fritz

[["dc.bibliographiccitation.firstpage","851"],["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Geology"],["dc.bibliographiccitation.lastpage","854"],["dc.bibliographiccitation.volume","28"],["dc.contributor.author","Neuweiler, Fritz"],["dc.contributor.author","Rutsch, M."],["dc.contributor.author","Geipel, G."],["dc.contributor.author","Reimer, Andreas"],["dc.contributor.author","Heise, K. H."],["dc.date.accessioned","2018-11-07T10:30:38Z"],["dc.date.available","2018-11-07T10:30:38Z"],["dc.date.issued","2000"],["dc.description.abstract","Albian carbonate mud-mound limestones exposed near Iraneta, northern Spain, show a fabric- and particle-specific fluorescence. Intense fluorescence is restricted to in situ precipitated microcrystalline (automicritic) fabrics, calcified demosponges, and coralline sponges. Intermediate intensity derives from micritized bioclasts, pellets, and a rim of marine bladed cement. Most invertebrate skeletons, late-diagenetic equant cement, and crosscutting zones of dolomitization are weakly to nonfluorescent. Internal microcrystalline sediment (allomicrite) and red algae debris have variable fluorescence. Correlation between rock fluorescence and soluble humic substances was evaluated from 3 g of automicrite, allomicrite, and cement. Time-resolved laser-induced fluorescence spectroscopy (TRLFS) with ultra-short pulses on two extracrystalline fractions (NaOH-soluble) and two intracrystalline fractions (HCl-soluble and NaOH-soluble) showed that most of the soluble humic substances of automicrite are within the crystals; but conversely, are significantly enriched on outer surfaces of allomicrite. Spar cement is close to detection limits. Fluorescence lifetimes are in the range of 0.5-2 ns and 3.5-6 ns. We conclude that precipitation of automicrite took place during oxidative organic matter diagenesis, i.e., during condensation reactions of degradation products of marine biopolymers. By contrast, allomicrite formed by skeletal breakdown followed by ingestion, organic coating, and reingestion during deposit feeding. A humic-substance-based model of marine polymer gels represents a new approach for the understanding of ancient polygenetic carbonate muds, so typical of Phanerozoic mud-mounds in deeper water settings."],["dc.identifier.doi","10.1130/0091-7613(2000)028<0851:SHSFIS>2.3.CO;2"],["dc.identifier.isi","000089269100021"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/43909"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","0091-7613"],["dc.title","Soluble humic substances from in situ precipitated microcrystalline calcium carbonate, internal sediment, and spar cement in a Cretaceous carbonate mud-mound"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","681"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","Geology"],["dc.bibliographiccitation.lastpage","684"],["dc.bibliographiccitation.volume","31"],["dc.contributor.author","Neuweiler, F."],["dc.contributor.author","d'Orazio, V."],["dc.contributor.author","Immenhauser, A."],["dc.contributor.author","Geipel, G."],["dc.contributor.author","Heise, K. H."],["dc.contributor.author","Cocozza, C."],["dc.contributor.author","Miano, T. M."],["dc.date.accessioned","2018-11-07T10:37:16Z"],["dc.date.available","2018-11-07T10:37:16Z"],["dc.date.issued","2003"],["dc.description.abstract","Intracrystalline organic compounds, enclosed within in situ-precipitated marine microcrystalline calcite (automicrite), might represent either an inclusion or the catalyst of such precipitation. We use evidence from a Lower Cretaceous deep-water carbonate mound to show (1) the original source, (2) the degree of condensation, (3) the redox conditions involved, and (4) the catalytic role of natural organic matter for the precipitation of automicrite. Fluorescence spectrometry of the intracrystalline organic fraction extracted from these carbonates identifies a marine fulvic acid-like organic compound with a low degree of pollycondensation. This finding points to a temporal correlation of the initial stage of geo-polymer formation with the precipitation of automicrite. Furthermore, the rare earth element (REE) distribution patterns in the mineral show a consistent positive Ce anomaly, suggesting an episode of reductive dissolution of iron-manganese oxyhydroxides during automicrite formation. In general, a relative enrichment of middle-weight REEs is observed, resulting in a convex distribution pattern typical for, e.g., phosphate concretions or humic acid material. By merging the results of spectrometry and REE geochemistry we thus conclude that the marine calcite precipitation was catalyzed by marine fulvic acid-like compounds during the early stages of humification under suboxic conditions. This indicates that humification, driven by the presence of a benthic biomass, is more important for calcite authigenesis than any site-specific microbial metabolism. The Neoproterozoic rise of carbonate mounds supports this hypothesis; there is molecular evidence for early metazoan divergence then, but not for a major evolutionary episode of microorganisms."],["dc.identifier.doi","10.1130/G19775.1"],["dc.identifier.isi","000184658400007"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/45521"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Geological Soc Amer, Inc"],["dc.relation.issn","1943-2682"],["dc.relation.issn","0091-7613"],["dc.title","Fulvic acid-like organic compounds control nucleation of marine calcite under suboxic conditions"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]