title: Combining µXANES and µXRD mapping to analyse the heterogeneity in calcium carbonate granules excreted by the earthworm Lumbricus terrestris.
abstract: The use of fluorescence full spectral micro-X-ray absorption near-edge structure (µXANES) mapping is becoming more widespread in the hard energy regime. This experimental method using the Ca K-edge combined with micro-X-ray diffraction (µXRD) mapping of the same sample has been enabled on beamline I18 at Diamond Light Source. This combined approach has been used to probe both long- and short-range order in calcium carbonate granules produced by the earthworm Lumbricus terrestris. In granules produced by earthworms cultured in a control artificial soil, calcite and vaterite are observed in the granules. However, granules produced by earthworms cultivated in the same artificial soil amended with 500 p.p.m. Mg also contain an aragonite. The two techniques, µXRD and µXANES, probe different sample volumes but there is good agreement in the phase maps produced.
authors.affiliation: Science Division, Diamond Light Source, Harwell Campus, Didcot, Oxon OX11 0DE, UK.
authors.forename: Loredana
authors.initials: L
authors.lastname: Brinza
authors.affiliation: Mineral and Planetary Sciences Division, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Schofield
authors.affiliation: Environment Department, University of York, York YO10 5DD, UK.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Hodson
authors.affiliation: Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, UK.
authors.forename: Sophie
authors.initials: S
authors.lastname: Weller
authors.affiliation: Science Division, Diamond Light Source, Harwell Campus, Didcot, Oxon OX11 0DE, UK.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Ignatyev
authors.affiliation: Science Division, Diamond Light Source, Harwell Campus, Didcot, Oxon OX11 0DE, UK.
authors.forename: Kalotina
authors.initials: K
authors.lastname: Geraki
authors.affiliation: Science Division, Diamond Light Source, Harwell Campus, Didcot, Oxon OX11 0DE, UK.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Quinn
authors.affiliation: Science Division, Diamond Light Source, Harwell Campus, Didcot, Oxon OX11 0DE, UK.
authors.forename: J Frederick W
authors.initials: JF
authors.lastname: Mosselmans
mesh_terms: D000818:Animals; D002119:Calcium Carbonate / Q000737:chemistry*; D016000:Cluster Analysis; D009835:Oligochaeta / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy / Q000379:methods*; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D002119:Calcium Carbonate
keywords: earthworm granules; full spectral XANES imaging; microfocus diffraction mapping