• SEM-microphotogrammetry, a new take on an old method for generating high-resolution 3D models from SEM images

      BALL, AD; JOB, PA; WALKER, AEL (Wiley, 2017-03-22)
      The method we present here uses a scanning electron microscope programmed via macros to automatically capture dozens of images at suitable angles to generate accurate, detailed three‐dimensional (3D) surface models with micron‐scale resolution. We demonstrate that it is possible to use these Scanning Electron Microscope (SEM) images in conjunction with commercially available software originally developed for photogrammetry reconstructions from Digital Single Lens Reflex (DSLR) cameras and to reconstruct 3D models of the specimen. These 3D models can then be exported as polygon meshes and eventually 3D printed. This technique offers the potential to obtain data suitable to reconstruct very tiny features (e.g. diatoms, butterfly scales and mineral fabrics) at nanometre resolution. Ultimately, we foresee this as being a useful tool for better understanding spatial relationships at very high resolution. However, our motivation is also to use it to produce 3D models to be used in public outreach events and exhibitions, especially for the blind or partially sighted.
    • The air-abrasive technique: a re-evaluation of its use in fossil preparation.

      Graham, M; Allington-Jones, L
      This paper outlines the history of air-abrasion (also known as airbrasion) as a palaeontological preparation technique and evaluates various powders and their properties. It explores the rationale behind the selection of abrasive powders and presents, for the first time, trench-scatter experiments through Scanning Electron Microscope (SEM) photography and three-dimensional (3-D) profiling. This article also offers general practical advice and details the results of an international survey of practising fossil preparators
    • Size effect on the mineralogy and chemistry of Mytilus trossulus shells from the southern Baltic Sea: implications for environmental monitoring

      Piwoni-Piórewicz, A; Kukliński, P; Strekopytov, S; Humphreys-Williams, E; Najorka, J; Iglikowska, A (2017-04)
    • Impact vaporization and Condensation: Laser Irradiation Experiments with Natural Planetary Materials

      Hamann, C; Hecht, L; Schäffer, S; Heunoske, D; Salge, T; Garbout, A; Osterholz, J; Greshake, A (The Woodlands, Texas, USA, 2018)
    • HYPERVELOCITY IMPACT IN LOW EARTH ORBIT: FINDING SUBTLE IMPACTOR SIGNATURES ON THE HUBBLE SPACE TELESCOPE

      Kearsley, AT; Colaux, JL; Wozniakiewicz, PJ; Gerlach, L; Anz-Meador, P; Liou, JC; Griffin, T; Reed, B; Opiela, J; Palitsin, VV; Grime, GW; Webb, RP; Jeynes, C; Spratt, J; Cole, MJ; Price, MC; Burchell, MJ; Salge, T
      HYPERVELOCITY IMPACT IN LOW EARTH ORBIT: FINDING SUBTLE IMPACTOR SIGNATURES ON THE HUBBLE SPACE TELESCOPE A T Kearsley 1,2,5, J L Colaux 3, D K Ross 4, P J Wozniakiewicz 2,5, L Gerlach 6, P Anz-Meador 4, J-C Liou 7, T Griffin 8, B Reed 8, J Opiela 4, V V Palitsin 3, G W Grime 3, R P Webb 3, C Jeynes 3, J Spratt 2, M J Cole 5, M C Price 5 and M J Burchell 5. 1 Dunholme, Raven Hall Road, Ravenscar, YO13 0NA, UK (kearsleys@runbox.com); 2 Natural History Museum (NHM), Cromwell Road, London, UK. 3 Ion Beam Centre, University of Surrey, Guildford, UK. 4 ESCG-Jacobs, NASA-JSC, Houston, TX, USA. 5 School of Physical Sciences, University of Kent, Canterbury, Kent, UK. 6 European Space Agency (ESA, retired), Noordwijk, The Netherlands. 7 NASA Johnson Space Center, Houston, TX, USA. 8 NASA Goddard Space Flight Center (GSFC), Greenbelt, Maryland, USA. ABSTRACT Introduction Return of large surface area components from the Hubble Space Telescope (HST) during shuttle orbiter service missions has allowed inspection of large numbers of hyper-velocity impact features from long exposure in low Earth orbit (LEO). Particular attention has been paid to the origin of the impacting particles, whether artificial Orbital Debris (OD) or natural Micrometeoroid (MM). Extensive studies have been made of solar cells (Graham et al., 2001; Kearsley et al 2005, Moussi et al., 2005) and recently, the painted metal surface of the Wide Field and Planetary Camera 2 WFPC2 radiator shield (Anz-Meador et al., 2013; Colaux et al., 2014; Kearsley et al., 2014a; Ross et al., 2014). Both of these materials from HST have layers of complex chemical composition, into which particle fragments and melt may infiltrate during impact. Experimental light gas gun (LGG) impacts (e.g. Price et al., 2014) have shown that impactor remains may be dispersed and dilute, often as a very thin and patchy coating within an irregular impact-generated pit. In previous studies, the low concentration of particle residue, the rugged topography of impact features, and especially the complex multi-element composition of the impacted surface were considered significant barriers to recognition of extraneous impactor-derived components. Analysis was both difficult and time consuming (e.g. Graham et al., 2001), and a substantial proportion of impactors (25-65%) could not be identified. Recent advances in energy dispersive X-ray microanalysis (EDX) now permit routine identification of impactor origins using scanning electron microscope (SEM); particle induced X-ray emission (PIXE) and micro-X-ray fluorescence (µ-XRF) instruments (Kearsley et al., 2012, 2014b). Here we demonstrate how these techniques have allowed impactor composition to be isolated, and the particle source determined for the great majority of WFPC2 samples studied. Methods To analyse impact melt on the zinc orthotitanate (ZOT) and aluminium alloy (Al-6061) of the WFPC2 radiator shield we used the Oxford Instruments INCA SEM-EDX spectrum pro-cessing software to separate peak and background X-ray counts for specified X-ray emission lines. From tables of likely OD and MM signature elements (e.g. Kearsley et al., 2005), and knowledge of the pristine WFPC paint and alloy compositions, we extracted data for the fol-lowing elements: Mg, Al, Si, S, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu and Zn. Two types of graphical plot were developed, to highlight extraneous element signatures in small impacts on the ZOT paint (Fig. 1), and larger craters into the Al-alloy (Fig. 2). The impactor origin was then clas-sified by reference to a suite of decision trees (Kearsley et al., 2012). A Bruker X-Flash 6050 EDX detector was also used to obtain signal from the interior of deeper craters. PIXE maps and spectra were acquired in the Ion Beam Centre, University of Surrey (Colaux et al., 2014). Results Figure 1. WFPC2 impact feature 339: a) SEM backscattered electron (BE) image; b) SEM depth model; c) SEM-EDX maps show high Mg concentration in the impact melt lining the impact feature d) plots of SEM-EDX X-ray counts for Mg and Fe show much higher levels in impact melt (red) than in clean ZOT paint (blue), and a similar level to impact residue from LGG impacts of olivine grains (open black squares). Excess Mg and Fe contents in frothy impact melt show impactor was a micrometeoroid. Figure 2). WFPC2 impact feature 462: a) SEM BE image; b) SEM depth profile; c and d) PIXE EDX maps show Fe and Ni across crater pit and surrounding metal, some iron-rich in-clusions in the Al alloy, but Ni only enriched in pit; e) PIXE EDX spectra show high Fe and Ni on crater floor, similar to micrometeoroid metal composition; f) plot of Mg/Al versus Cr/Fe X-ray counts in SEM-EDX spectra from the crater edge (red) show enrichment of Mg and Fe over alloy composition (black, grey, yellow and green), indicating a mafic silicate mi-crometeoroid component has also been added from the impacted micrometeoroid. Summary and conclusions Together, SEM-EDX and PIXE-EDX maps, spectra and X-ray count plots showed 166 MM residues and 2 OD residues in this survey of 188 impact features on WFPC2, ~ 90% of those examined, considerable enhancement of impactor recognition over an earlier study of HST impacts (~75% identified as MM or OD in origin, Kearsley et al., 2005). Acknowledgements ESA contract 40001105713/12/NL/GE awarded to NHM and the University of Surrey; Bruker for expertise in use of the X-Flash detector and loan of the M4 Tornado µ-XRF. References quoted Anz-Meador P. et al. (2013) Proc. 6th European Conf. Space Debris, ESA SP 723: s1b_anzme.pdf, CD-ROM. Colaux J. L. et al. (2014) LPSC 45 Abstract #1727. Graham, G.A. et al. (2001) Proc. 3rd European Conf. Space Debris, ESA SP 473:197–203. Kearsley A.T. et al., (2005) Adv. Space Res. 35:1254–1262. Kearsley A. T. et al. (2012) Technical Note 1 for ESA contract 40001105713/12/NL/GE. Kearsley A. T. et al. (2014a) LPSC 45 abstract #1722. Kearsley A.T. et al. (2014b) LPSC 45 abstract #1733. Moussi A. et al. (2005) Adv. Space Res. 35:1243–1253. Price M. C. et al. (2014) LPSC 45 abstract #1466. Ross D. K. et al. (2014) LPSC 45 abstract #1514.
    • The origin of secondary heavy rare earth element enrichment in carbonatites: Constraints from the evolution of the Huanglongpu district, China

      Smith, M; Kynicky, J; Chen, X; Wenlei, S; Spratt, J; Jeffries, T; Brnicky, M; Kopriva, A; Cangeloosi, D (2018-03-04)
    • The Clacton Spear: the last one hundred years

      Allington-Jones, L (Royal Archaeological Institute, 2015)
      In 1911 an eminent amateur prehistorian pulled the broken end of a pointed wooden shaft from Palaeolithic-age sediments at a seaside town in Essex. This artefact, still the earliest worked wood to be discovered in the world, became known as the Clacton Spear. Over the past 100 years it has variously been interpreted as a projectile weapon, a stave, a digging stick, a snow probe, a lance, a game stake and a prod to ward off rival scavengers. These perspectives have followed academic fashions, as the popular views of early hominins have altered. Since discovery the Clacton spear has also been replicated twice, has undergone physical transformations due to preservation treatments, and has featured in two public exhibitions. Within this article the changing context of the spear, its parallels, and all previous conservation treatments and their impacts are assessed.
    • The remedial conservation and support jacketing of the Massospondylus carinatus neotype

      Graham, M; Choiniere, JN; Jirah, S; Barrett, PM (Palaeontologia africana, 2018-03-27)
      Massopondylus carinatus Owen, 1854 is a non-sauropodan sauropodomorph (‘prosauropod’) dinosaur whose remains are abundant in the Upper Karoo Supergroup sediments of southern Africa (e.g. Owen, 1854; Seeley, 1895; Cooper, 1981; Gow, 1990; Gow et al., 1990; Sues et al., 2004; Barrett and Yates, 2006; Reisz et al., 2005). It occurs at numerous localities in the Upper Elliot and Clarens formations of South Africa and Lesotho, as well as in the Forest Sandstone Formation of Zimbabwe (Haughton, 1924; Cooper, 1981; Kitching and Raath, 1984). Several almost complete skeletons are known, including skulls, and as a result Massospondylus has featured heavily in discussions of early dinosaur ecology, phylogeny and palaeobiology (e.g. Cooper, 1981; Barrett, 2000; Zelenitsky and Modesto, 2002; Reisz et al., 2005, 2012, Apaldetti et al., 2011, among many others). However, the original syntype series of Massospondylus carinatus was destroyed during World War II and shown to be taxonomically indeterminate, undermining the nomenclatural stability of this important taxon (Sues et al. 2004; Yates and Barrett, 2010). In order to rectify this problem, a complete skeleton representing an adult individual, BP/1/4934 (nicknamed ‘Big Momma’), was designated as the neotype (Yates and Barrett, 2010). BP/1/4934 was collected from the Upper Elliot Formation of Bormansdrift Farm, in the Clocholan District of the Free State, by Lucas Huma and James Kitching in 1980 (see Kitching and Raath, 1984, for locality details). This farm is also the type locality of the early turtle Australochelys (Gaffney and Kitching, 1994) and has yielded other Upper Elliot formation tetrapod material including the cynodont Pachygenelus and other sauropodomorph remains (Kitching and Raath, 1984). BP/1/4934 is the most complete specimen of a non-sauropodan sauropodomorph dinosaur known from the entire African continent and is therefore of major regional and international significance. In addition, since 1990 it has formed part of a permanent public exhibit showcasing African palaeontological discoveries in the J. W. Kitching Gallery of the Evolutionary Studies Institute (ESI) of the University of the Witwatersrand. During recent research work on BP/1/4934, as part of an on-going collaboration on early dinosaurs between the ESI and Natural History Museum, London (NHMUK), it was noted that its condition had deteriorated and that urgent remedial conservation work was required in order to preserve it for future generations. As a result, the specimen was temporarily removed from public display to facilitate this work, which is described in detail below (see also Graham, 2017). The primary purpose of the conservation project was to assess the condition of the specimen, undertake conservation in order to stabilise it and to manufacture ‘clam-shell’ type support mounts/jackets for each of the blocks to enable the specimen to be displayed in an articulated posture within a purpose-built display case. An important consideration was that the blocks should be readily accessible from both left and right sides to researchers whilst securing the fossil safely. Finally, this project also provided an opportunity to facilitate knowledge exchange between the conservation staff at the ESI and NHMUK, in order to share and extend technical expertise.
    • Characterisation of nanoparticles by means of high-resolution SEM/EDS in transmission mode

      Hodoroaba, V-D; Rades, S; Salge, T; Mielke, J; Ortel, E; Schmidt, R (2016-02-09)
    • Identification of fossil worm tubes from Phanerozoic hydrothermal vents and cold seeps

      Georgieva, MN; Little, CTS; Watson, JS; Sephton, MA; Ball, AD; Glover, AG (2017-12-28)
    • Conservation of James Sowerby’s Fungi Models

      Bernucci, A; Allington-Jones, L (2015)
    • iCollections

      Paterson, GLJ; Albuquerque, S; Blagoderov, V; Brooks, S; Cafferty, S; Cane, E; Carter, V; Chainey, J; Crowther, R; Douglas, L; Durant, J; Duffle, L; Hine, A; Honey, M; Huertas, B; Howard, T; Huxley, R; Kitching, IJ; Ledger, S; McLaughlin, C; Martin, G; Mazzetta, G; Penn, M; Perera, J; Sadka, M; Scialabba, E; Siebert, D; Sleep, C; Toloni, F; Wing, P (2016-06-03)
      iCollections specimens
    • Graham MR. (2017) The remedial conservation and support jacketing of the neotype specimen of the dinosaur Massospondylus carinatus

      Graham, M (PeerJ Inc., 2017-08-09)
      In March 2017 the neotype specimen of the Early Jurassic South African prosauropod dinosaur Massospondylus carinatus was appraised and condition reported at the Evolutionary Studies Institute, University of the Witwatersrand (WITS), Johannesburg, in readiness for remedial conservation and re-storage. The work was necessitated by deterioration of the specimen, which was caused by handling over a number of years and an inadequate and failing support mount. Formally numbered BP/1/4934, but more affectionately known to staff as ‘Big Momma’, the specimen was contained within several individual blocks on flimsy support bases and presented various conservation challenges.These included treatment of fractures and cracking across several surfaces of the fossil and the production of clam shell supports to allow for articulated display within the constraints of an existing display cabinet. Part of the brief was to facilitate safer handling and access for researchers. This project was led by the author who also trained the curatorial and preparation staff at WITS in the methods and techniques employed. The visit was funded by the Palaeontological Scientific Trust (PAST), the DST/NRF Centre of Excellence in Palaeosciences and The University of the Witwatersrand (WITS).
    • Hypervelocity impact in low earth orbit: finding subtle impactor signatures on the Hubble Space Telescope

      Kearsley, AT; Colaux, JL; Ross, DK; Wozniakiewicz, PL; Gerlach, L; Anz-Meador, P; Griffin, T; Reed, B; Opiela, J; Palitsin, VV; Grime, GW; Webb, RP; Jeynes, C; Spratt, J; Salge, T; Cole, MJ; Price, MC; Burchell, MJ (2017)
    • Mineralization of Alvinella polychaete tubes at hydrothermal vents

      Georgieva, MN; Little, CTS; Ball, AD; Glover, AG (2015-03)