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  • Journal article
    Perry RS, Lynne BY, Sephton MA, Kolb VM, Perry CC, Staley JTet al., 2006,

    Baking black opal in the desert sun: the importance of silica in desert varnish, 2006, Geology, 34, 537-540

    , Geology, Vol: 34, Pages: 537-540, ISSN: 0091-7613
  • Journal article
    Sephton MA, 2005,

    , PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 363, Pages: 2729-2742, ISSN: 1364-503X
    • Cite
    • Citations: 43
  • Journal article
    Bada JL, Sephton MA, Ehrenfreund P, Mathies RA, Skelley AM, Grunthaner FJ, Zent AP, Quinn RC, Josset JL, Robert F, Botta O, Glavin DPet al., 2005,

    , ASTRONOMY & GEOPHYSICS, Vol: 46, Pages: 26-27, ISSN: 1366-8781
    • Cite
    • Citations: 25
  • Journal article
    Sephton MA, Looy CV, Brinkhuis H, Wignall PB, de Leeuw JW, Visscher Het al., 2005,

    , GEOLOGY, Vol: 33, Pages: 941-944, ISSN: 0091-7613
    • Cite
    • Citations: 237
  • Journal article
    Sephton MA, Love GD, Meredith W, Snape CE, Sun CG, Watson JSet al., 2005,

    , PLANETARY AND SPACE SCIENCE, Vol: 53, Pages: 1280-1286, ISSN: 0032-0633
    • Cite
    • Citations: 27
  • Journal article
    Verchovsky AB, Sephton MA, 2005,

    , ASTRONOMY & GEOPHYSICS, Vol: 46, Pages: 12-14, ISSN: 1366-8781
  • Conference paper
    Perry RS, Kolb VM, Philip A I, Lynne BY, Mcloughlin N, Sephton MA, Wacey D, Green ORet al., 2005,

    , Conference on Astrobiology and Planetary Missions, Publisher: The International Society for Optical Engineering, Pages: 1-11
  • Journal article
    Sephton MA, Botta O, 2005,

    Recognizing life in the solar system: guidance from meteoritic organic matter

    , INT J ASTROBIOL, Vol: 4, Pages: 269-276, ISSN: 1473-5504
  • Journal article
    Sephton MA, Meredith W, Sun CG, Snape CEet al., 2005,

    , RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Vol: 19, Pages: 323-325, ISSN: 0951-4198
    • Cite
    • Citations: 17
  • Conference paper
    Perry RS, Kolb VM, Lynne BY, Sephton MA, Mcloughlin N, Engel MH, Olendzenski L, Brasier M, Staley JTet al., 2005,

    , Conference on Astrobiology and Planetary Missions, Publisher: The International Society for Optical Engineering, Pages: 1-12
  • Journal article
    Sephton MA, Meredith W, Sun CG, Snape CEet al., 2005,

    , RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Vol: 19, Pages: 3339-3342, ISSN: 0951-4198
  • Conference paper
    Sephton MA, Looy CV, Visscher H, Brinkhuis H, de Leeuw JWet al., 2005,

    The combined petrographic and chemical analysis of end-Permian kerogens

    , 8th International Meeting on Response of the Earth System to Impact Processes (IMPACT), Pages: 467-478

    The end of the Permian was marked by one of the greatest mass extinctions of all time. A valuable record of life and death during this event is contained within sedimentary organic matter. The stable isotopic, molecular and morphological information contained within remains of end-Permian organisms represent an important resource for scientists attempting to produce paleoenvironment reconstructions. Most meaningful data derive from multidisciplinary analyses of the same samples. In these circumstances it is desirable that sample preparation for one approach does not hinder subsequent analysis by another. To ensure compatibility of sample processing procedures the petrographic and chemical consequences of two common kerogen preparation steps, demineralization and screening (sieving), were simultaneously monitored using transmitted light microscopy and flash pyrolysis. Two end-Permian sediments, whose organic content was predominated by land-plant debris, were chosen for this purpose. A limestone was used to assess the problem of fluoride production when dematerializing carbonates and a marl was used to investigate the possibility of introducing a sampling bias following kerogen screening. Flash pyrolysis results of demineralization residues indicate that neoformed fluorides can be effectively removed by repeated treatments with excess concentrated HCl. Flash pyrolysis of screened size fractions (< 10 mu m, 10-18 mu m, 18-30 mu m, 30-125 mu m, 125-250 mu m, > 250 mu m) suggest that, for the end-Permian kerogen used, the various fractions are qualitatively representative of the unscreened kerogen. In a paleoenvironmental context, the homogeneity of the land plant derived kerogen reflects a period of organic accumulation on land followed by rapid deposition and burial in a marine setting. These findings constitute a step forward in the quest for parity between petrographic and chemical analyses of the same kerogen samples.
  • Journal article
    Watson JS, Sephton MA, Looy CV, Gilmour Let al., 2005,

    , ORGANIC GEOCHEMISTRY, Vol: 36, Pages: 371-384, ISSN: 0146-6380
    • Cite
    • Citations: 27
  • Journal article
    Koeberl C, Farley KA, Peucker-Ehrenbrink B, Sephton MAet al., 2004,

    , GEOLOGY, Vol: 32, Pages: 1053-1056, ISSN: 0091-7613
    • Cite
    • Citations: 70
  • Journal article
    Sephton MA, James RH, Bland PA, 2004,

    , ASTROPHYSICAL JOURNAL, Vol: 612, Pages: 588-591, ISSN: 0004-637X
    • Cite
    • Citations: 15
  • Journal article
    Visscher H, Looy CV, Collinson ME, Brinkhuis H, Cittert JHAVKV, K眉rschner WM, Sephton MAet al., 2004,

    , PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 101, Pages: 12952-12956, ISSN: 0027-8424
    • Cite
    • Citations: 212
  • Journal article
    Sephton MA, Bland PA, Pillinger CT, Gilmour Iet al., 2004,

    , METEORITICS & PLANETARY SCIENCE, Vol: 39, Pages: 747-754, ISSN: 1086-9379
    • Cite
    • Citations: 30
  • Journal article
    Sephton MA, 2004,

    , ASTRONOMY & GEOPHYSICS, Vol: 45, Pages: 8-14, ISSN: 1366-8781
    • Cite
    • Citations: 24
  • Journal article
    Sephton MA, Love GD, Watson JS, Verchovsky AB, Wright IP, Snape CE, Gilmour Iet al., 2004,

    , GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 68, Pages: 1385-1393, ISSN: 0016-7037
    • Cite
    • Citations: 108
  • Journal article
    Butterworth AL, Aballain O, Chappellaz J, Sephton MAet al., 2004,

    Combined element (H and C) stable isotope ratios of methane in carbonaceous chondrites

    , MON NOT R ASTRON SOC, Vol: 347, Pages: 807-812, ISSN: 0035-8711

    We have performed the first ever combined-element stable isotopic measurements of extraterrestrial molecules. Methane from two carbonaceous chondrites, Murchison and Cold Bokkeveld, was measured for its hydrogen and carbon isotopic compositions. The combined isotopic composition of meteoritic methane reveals information about the indigenous nature of volatile aliphatic organic matter in meteorites and its probable extraterrestrial source environment. Deuterium enrichments relative to the solar nebula 4.6 Gyr ago reflect a contribution from low-temperature chemical reactions in interstellar space. Similar carbon but different hydrogen isotopic compositions for methane in the two meteorite samples probably represent comparable primary origins but varying levels of secondary processing and exchange with isotopically light hydrogen. Our high precision laboratory-obtained measurements provide valuable reference points for observational spectroscopists undertaking astronomical investigations of the stable isotopic composition of extraterrestrial methane.

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