Goldschmidt2013 Conference Abstracts 1239 U!–Pb chronology and REE Oxygen transfer across the capillary geochemistry of large zircons in fringe: Impact of transient flow Estherville mesosiderite conditions and coarse-material lenses MAKIKO K. HABA1*, AKIRA YAMAGUCHI2, HIROYUKI C.M. HABERER1*, M. ROLLE1,2, O.A. CIRPKA1 KAGI1, KEISUKE NAGAO1 AND HIROSHI HIDAKA3 AND P. GRATHWOHL1 1Geochemical Research Center, University of Tokyo, 1Department of Geosciences, University of Tübingen, Bunkyo-ku, Tokyo 113-0033, Japan (correspondence: Hölderlinstraße 12, 72074 Tübingen, Germany [email protected]) (*correspondence: [email protected]) 2Antarctic Meteorite Research Center, National Institute of 2Department of Civil & Environmental Engineering, Stanford Polar Research, Tachikawa, Tokyo 190-8518, Japan University, 473 Via Ortega, Stanford, CA 94305, USA. 3Department of Earth and Planetary Systems Science, Higashi- Hiroshima, Hiroshima 739-8526, Japan We performed quasi 2-D flow-through experiments at the laboratory bench-scale to investigate the impact of transient Mesosiderites are breccias composed of almost equal flow conditions and a coarse-material inclusion on oxygen proportions of silicates and Fe-Ni metal. The oxygen isotopic transfer from the unsaturated zone, across the capillary fringe compositions of the silicate parts of mesosiderites and HED (CF), to anoxic water. The experimental setup consists of a (howardite, eucrite, and diogenite) meteorites indicate that flow-through chamber with inner dimensions of 80 cm ! 40 their parent bodies are same or located in the same region [1]. cm ! 0.5 cm (Fig. 1). Glass beads with two different ranges in However, an origin and formation histories of mesosiderites grain diameter were used as porous media. We applied a non- are still enigmatic, because they have experienced complex invasive optode technique to measure high-resolution vertical metamorphism [2]. In this study, we report results of in situ O2-concentration profiles across the CF at several distances analyses of large zircons found in Estherville mesosiderite. from the inlet of the flow-through chamber. In addition, the An electron probe micro-analyser was used to identify a oxygen flux at the inlet and in the effluent of the flow-through zircon by elemental mappings of Zr and Si and for quantitative chamber was monitored over time. analysis of major elements. Crystallinity and structure of zircons were evaluated by Raman spectra and cathodoluminecence (CL) images, respectively. U–Pb isotopes and rare earth elements (REE) contents were analyzed using a sensitive high resolution ion micro-probe (SHRIMP). Two large zircons, 30 ! 100 µm and 100 ! 300 µm, were found. The CL images and Raman spectra indicate that the larger zircon consists of several domains. U and REE contents of the most part of the zircons are quite low compared with those in basaltic eucrites [3, 4]. However, the larger zircon has U- and REE-enriched area where U and REE contents are well Figure 1. Experimental setup with coarse-material inclusion. consistent with those in basaltic eucrites. The 207Pb–206Pb age The red dye (New Coccine) was used to visualize the flow of the U- and REE-enriched area is 4520 ± 14 Ma (2", n = 3), field. which is younger than zircons in basaltic eucrites [3] and Vaca Muerta (mesosiderite) [5]. These results suggest that the In homogeneous porous material, we quantified the effect original zircons in Estherville were similar to those in basaltic of different water table dynamics, i.e., slow and fast water eucrites and could have recrystallized and overgrown during table fluctuations, on oxygen transfer. Enhanced O2-supply the metal-silicate mixing event. was observed in case of slow fluctuations due to pronounced partitioning from entrapped air. In case of a fast draining water [1] Clayton and Mayeda (1996) GCA 60, 1999–2017. [2] table the effect of specific yield has to be considered. The Wadhwa et al (2003) GCA 67, 5047–5069. [3] Misawa et al experiments performed in the heterogeneous system showed (2005) GCA 69, 5847–5861. [4] Haba et al (2013) LPSC 44, that oxygen transfer was significantly increased by the coarse- #1989. [5] Ireland and Wlotzka (1992) EPSL 109, 1–10. material inclusion due to flow focusing, the capillary barrier effect, and the presence of an air passage. These processes contributed to the overall enhancement of O2-transfer through the CF to the underlying anoxic groundwater up to seven times compared to what was observed in the homogeneous experimental setup. www.minersoc.org DOI:10.1180/minmag.2013.077.5.8 Downloaded from http://pubs.geoscienceworld.org/minmag/article-pdf/77/5/1239/2920692/gsminmag.77.5.08-H.pdf by guest on 29 September 2021 1240 Goldschmidt2013 Conference Abstracts Influence of bacterial biomass on Campaign-style titanite U-Pb dating transport kinetics of phenanthrene by laser-ablation ICP: Implications N. HACHICHO*, A. MILTNER, L.Y. WICK for crustal flow, phase AND M. KÄSTNER transformations and titanite closure UFZ - Helmholtz Centre for Environmental Research Leipzig, 1 1 B.R HACKER A.R.C. KYLANDER-CLARK Germany (*correspondence: [email protected]) 2A 1 T.B. ANDERSEN AND J.M. COTTLE Introduction 1Earth Science, University of California, Santa Barbara CA In soils, both pollutants and pollutant-degrading organisms 93106, USA ([email protected]) are heterogeneously distributed. For an efficient site 2Geosciences, Universitetet i Oslo, P.O. Box 1047 Blindern, remediation by biodegradation, transport of either the 0316 Oslo, Norway pollutant or the microorganisms is necessary. Earlier studies show the effect of fungal hyphae on the transport of both U-Pb dates of titanite from >150 samples of chemicals and bacteria by fungal highways or pipelines [1]. In quartzofeldspathic gneiss and leucosomes were measured our study we investigated how the presence of bacterial across the ultrahigh-pressure (UHP) Western Gneiss Region of biomass affects the diffusive transport of phenanthrene in Norway to understand deformation and metamorphism of aqueous solution in model systems (adapted from ref [2]) in continental crust during subduction and exhumation. Titanite the laboratory. is unstable at pressures > 1.5 GPa, and, indeed, most yielded Phenanthrene Transport in Passive Dosing Systems post-UHP dates. A number of titanites sampled across large We studied the transport of phenanthrene from a silicone areas, however, have pre-UHP U-Pb dates, indicating that the ring loaded with phenanthrene (source) to a larger clean titanites survived their excursion to and return from mantle silicone ring (sink). Both rings were placed in a vial depths metastably. This has three important implications. containing 1 ml of medium with or without bacteria not able to Titanite grains can remain closed to complete Pb loss during degrade phenanthrene at different cell densities. After xy regional metamorphism at temperatures as high as 750°C and hours, source, sink and medium were analysed separately for pressures as high as 3 GPa, implying that thermally mediated phenanthrene. volume diffusion was not the principal factor controlling resetting of the U-Pb system. Phase transformations in and Results and Discussion deformation of quartzofeldspathic rocks can be inhibited at the The presence of bacterial biomass increased the medium's same conditions. capacity for phenanthrene, but no difference in the phenanthrene contents in the source and the sink ring were found (Fig. 1). Further experiments with different soil bacteria with a range of surface properties and motilities will provide additional informationn to elucidate the role of bacterial biomass for the transport of chemicals in soil. Figure 1: Phenanthrene distribution in passive dosing systems with biofilm of Arthrobacter chlorophenolicus A6 on the surface (A) and sterile agar (B). [1] Banitz et al(2012) EnvironMicrobiolRep 2012, 1-8. [2]! Smith et al (2012) Environ. Sci. Technol. 46, 4852"4860. www.minersoc.org DOI:10.1180/minmag.2013.077.5.8 Downloaded from http://pubs.geoscienceworld.org/minmag/article-pdf/77/5/1239/2920692/gsminmag.77.5.08-H.pdf by guest on 29 September 2021 Goldschmidt2013 Conference Abstracts 1241 Interpretation of extreme diagenetic Carbon isotope gradients in the settings with a new thermodynamic Eocene as a constraint on the activity model biological pump, atmospheric CO2 LAURA HAFFERT1, MATTHIAS HAECKEL1, VOLKER and the ocean’s major ion LIEBETRAU1 AND DIRK DE BEER2 composition 1 Helmholtz Centre for Ocean Research Kiel (GEOMAR), 1 1 1 MATHIS P. HAIN , DANIEL M. SIGMAN , J. A. HIGGINS , Germany (*correspondence: [email protected], 2 AND GERALD H. HAUG [email protected], [email protected]) 2Max Planck Institute for Marine Microbiology, Bremen, 1Princeton University, ([email protected]) Germany ([email protected]) 2ETH Zürich A thermodynamic activity model (Pitzer approach) In the modern ocean surface the !13C of dissolved applicable to extreme environmental pTS-conditions (up to inorganic carbon (DIC) is high (13C-enriched) relative to deep 1000 bar, 200 °C and 6 M NaCl) coupled to an extensive waters, due to isotope fractionation during biological carbon mineral database has been developed. The advantage of this fixation and the subsequent export of organic matter from the code is the incorporation of a comprehensive pressure surface to sequester 13C-deplete carbon at depth, the soft-tissue correction, as well as the flexibility on the choice of input component of the biological pump. In the