Imperial College London

ProfessorMarkSephton

Faculty of EngineeringDepartment of Earth Science & Engineering

Head of the Department of Earth Science and Engineering
 
 
 
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Contact

 

+44 (0)20 7594 6542m.a.sephton Website

 
 
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Assistant

 

Ms Daphne Salazar +44 (0)20 7594 7401

 
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Location

 

G30 (via G28)Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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185 results found

Abrams MA, Gong C, Garnier C, Sephton MAet al., A new thermal extraction protocol to evaluate liquid rich unconventional oil in place and in-situ fluid chemistry, Marine and Petroleum Geology, ISSN: 1873-4073

Assessing oil in place and the proportion of oil that is producible are two critical measurements in evaluating liquid rich unconventional well and play economics. Current methodologies to evaluate Oil-In-Place (OIP) include log calculated estimates, petroleum systems charge modeling, and direct geochemical measurements. The standard open system programmed pyrolysis method has been modified to remove a broader range of thermally extracted free and adsorbed hydrocarbons and non-hydrocarbons in liquid rich unconventional plays. The added isotherms with a relatively low temperature start results in additional free hydrocarbon S1 peaks. The extra S1 peaks are used to assist in evaluating in-situ hydrocarbon quality. Examination of as received and post solvent extracted programmed pyrolysis data from replicate samples indicates a significant amount of solvent extractable free hydrocarbon is not captured in the S1 and rolls over into the S2 peak. This observation suggests the S1 peak may not represent total oil in place less evaporative losses. This paper examines a new multi-step high resolution on-column thermal extraction system to provide an inexpensive screening tool to map zones of higher in place oil and evaluate chemical characteristics which can be used to assist in estimating productivity. The thermal extraction unit is coupled to a flame ionization detector (FID) by a short uncoated capillary column to generate a high resolution thermal extraction profile (thermogram) with four temperature fractions. The area under each thermal peak provides direct measurements of volatized hydrocarbon and non-hydrocarbon compounds. Examination of individual compounds within each thermal fraction demonstrates multi-step thermal extraction is not a simple fractional distillation but also is impacted by inorganic and organic interactions. If we assume each thermal fraction represents oil compounds with increased complexity, then one can use peak area ratios to estimate in-situ fl

JOURNAL ARTICLE

Lewis JMT, Najorka J, Watson JS, Sephton MAet al., The search for Hesperian organic matter on Mars: Pyrolysis studies of sediments rich in sulfur and iron., Astrobiology, ISSN: 1531-1074

Jarosite on Mars is of significant geological and astrobiological interest as it forms in acidic aqueous conditions that are potentially habitable for acidophilic organisms. Jarosite can provide environmental context and may host organic matter. The most common analytical technique used to search for organic molecules on the surface of Mars is pyrolysis. However, thermal decomposition of jarosite produces oxygen, which degrades organic signals. At pH values greater than 3 and high water to rock ratios jarosite has a close association with goethite. Hematite can form by dehydration of goethite or directly from jarosite under certain aqueous conditions. Goethite and hematite are significantly more amenable for pyrolysis experiments searching for organic matter than jarosite. Analysis of the mineralogy and organic chemistry of samples from a natural acidic stream revealed a diverse response for organic compounds during pyrolysis of goethite-rich layers but a poor response for jarosite-rich or mixed jarosite-goethite units. Goethite units that are associated with jarosite but do not contain jarosite themselves should be targeted for organic detection pyrolysis experiments on Mars. These findings are extremely timely as future exploration targets for Mars Science Laboratory include Hematite Ridge, which may have formed from goethite precursors.

JOURNAL ARTICLE

Potiszil C, Montgomery W, Sephton MA, 2017, Effects of Pressure on Model Compounds of Meteorite Organic Matter, ACS Earth and Space Chemistry, ISSN: 2472-3452

JOURNAL ARTICLE

Sephton MA, 2017, Thermal extraction for organic-matter containing materials to answer questions both on Earth and in Space, First Break, Vol: 35, Pages: 113-117, ISSN: 1365-2397

The role of heat in the generation of petroleum has led to the study of organic matter-containing rocks by laboratory heating techniques. In particular, heat is used for the thermal extraction of organic matter in preparation for characterization by a range of detectors. Recently, thermal extraction has been used to answer certain planetary science questions such as the history of habitability for planets in the solar system and the search for evidence of life outside the Earth. The development of new thermal extraction protocols for challenging planetary science objectives provide methods that are readily translatable back to petroleum activities and include new shale screening and assessment techniques.

JOURNAL ARTICLE

Zafar R, Watson JS, Weiss DJ, Sephton MAet al., 2017, Organic compound-mineral interactions: Using flash pyrolysis to monitor the adsorption of fatty acids on calcite, JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS, Vol: 123, Pages: 184-203, ISSN: 0165-2370

JOURNAL ARTICLE

Gordon PR, Sephton MA, 2016, Rapid habitability assessment of Mars samples by pyrolysis-FTIR, Planetary and Space Science, Vol: 121, Pages: 60-75, ISSN: 1873-5088

Pyrolysis Fourier transform infrared spectroscopy (pyrolysis FTIR) is a potential sample selection method for Mars Sample Return missions. FTIR spectroscopy can be performed on solid and liquid samples but also on gases following preliminary thermal extraction, pyrolysis or gasification steps. The detection of hydrocarbon and non-hydrocarbon gases can reveal information on sample mineralogy and past habitability of the environment in which the sample was created. The absorption of IR radiation at specific wavenumbers by organic functional groups can indicate the presence and type of any organic matter present. Here we assess the utility of pyrolysis-FTIR to release water, carbon dioxide, sulphur dioxide and organic matter from Mars relevant materials to enable a rapid habitability assessment of target rocks for sample return. For our assessment a range of minerals were analysed by attenuated total reflectance FTIR. Subsequently, the mineral samples were subjected to single step pyrolysis and multi step pyrolysis and the products characterised by gas phase FTIR.Data from both single step and multi step pyrolysis-FTIR provide the ability to identify minerals that reflect habitable environments through their water and carbon dioxide responses. Multi step pyrolysis-FTIR can be used to gain more detailed information on the sources of the liberated water and carbon dioxide owing to the characteristic decomposition temperatures of different mineral phases. Habitation can be suggested when pyrolysis-FTIR indicates the presence of organic matter within the sample. Pyrolysis-FTIR, therefore, represents an effective method to assess whether Mars Sample Return target rocks represent habitable conditions and potential records of habitation and can play an important role in sample triage operations.

JOURNAL ARTICLE

Gordon PR, Sephton MA, 2016, Organic Matter Detection on Mars by Pyrolysis-FTIR: An Analysis of Sensitivity and Mineral Matrix Effects, ASTROBIOLOGY, Vol: 16, Pages: 831-845, ISSN: 1531-1074

JOURNAL ARTICLE

Jardine PE, Fraser WT, Lomax BH, Sephton MA, Shanahan TM, Miller CS, Gosling WDet al., 2016, Pollen and spores as biological recorders of past ultraviolet irradiance, SCIENTIFIC REPORTS, Vol: 6, ISSN: 2045-2322

JOURNAL ARTICLE

Matthewman R, Crawford IA, Jones AP, Joy KH, Sephton MAet al., 2016, Organic Matter Responses to Radiation under Lunar Conditions, ASTROBIOLOGY, Vol: 16, Pages: 900-912, ISSN: 1531-1074

JOURNAL ARTICLE

Montgomery W, Bromiley GD, Sephton MA, 2016, The nature of organic records in impact excavated rocks on Mars, SCIENTIFIC REPORTS, Vol: 6, ISSN: 2045-2322

JOURNAL ARTICLE

Montgomery W, Potiszil C, Watson JS, Sephton MAet al., 2016, Sporopollenin, a Natural Copolymer, is Robust under High Hydrostatic Pressure, MACROMOLECULAR CHEMISTRY AND PHYSICS, Vol: 217, Pages: 2494-2500, ISSN: 1022-1352

JOURNAL ARTICLE

Montgomery W, Sephton MA, 2016, PRESSURE EFFECTS IN POLYCYCLIC AROMATIC NITROGENATED HETEROCYCLES (PANHs): DIAGNOSTIC QUALITIES AND COSMOBAROMETRY POTENTIAL, ASTROPHYSICAL JOURNAL, Vol: 819, ISSN: 0004-637X

JOURNAL ARTICLE

Najorka J, Lewis JMT, Spratt J, Sephton MAet al., 2016, Single-crystal X-ray diffraction study of synthetic sodium-hydronium jarosite, PHYSICS AND CHEMISTRY OF MINERALS, Vol: 43, Pages: 377-386, ISSN: 0342-1791

JOURNAL ARTICLE

Abubakar R, Muxworthy AR, Sephton MA, Southern P, Watson JS, Fraser AJ, Almeida TPet al., 2015, Formation of magnetic minerals at hydrocarbon-generation conditions, Marine and Petroleum Geology, Vol: 68, Pages: 509-519, ISSN: 0264-8172

JOURNAL ARTICLE

Lewis JMT, Watson JS, Najorka J, Duy L, Sephton MAet al., 2015, Sulfate Minerals: A Problem for the Detection of Organic Compounds on Mars?, ASTROBIOLOGY, Vol: 15, Pages: 247-258, ISSN: 1531-1074

JOURNAL ARTICLE

Luong D, Sephton MA, Watson JS, 2015, Subcritical water extraction of organic matter from sedimentary rocks, ANALYTICA CHIMICA ACTA, Vol: 879, Pages: 48-57, ISSN: 0003-2670

JOURNAL ARTICLE

Matthewman R, Court RW, Crawford IA, Jones AP, Joy KH, Sephton MAet al., 2015, The Moon as a Recorder of Organic Evolution in the Early Solar System: A Lunar Regolith Analog Study, Astrobiology, Vol: 15, Pages: 154-168, ISSN: 1531-1074

JOURNAL ARTICLE

Montgomery W, Sephton MA, Watson JS, Zeng Het al., 2015, The Effects of Minerals on Heavy-Oil and Bitumen Chemistry When Recovered by Steam-Assisted Methods, Publisher: SPE-SOC PETROLEUM ENGINEERS, CANADA, Pages: 15-17, ISSN: 0021-9487

CONFERENCE PAPER

Montgomery W, Sephton MA, Watson JS, Zeng H, Rees ACet al., 2015, Minimising hydrogen sulphide generation during steam assisted production of heavy oil, SCIENTIFIC REPORTS, Vol: 5, ISSN: 2045-2322

JOURNAL ARTICLE

Mustafa KA, Sephton MA, Watson JS, Spathopoulos F, Krzywiec Pet al., 2015, Organic geochemical characteristics of black shales across the Ordovician-Silurian boundary in the Holy Cross Mountains, central Poland, MARINE AND PETROLEUM GEOLOGY, Vol: 66, Pages: 1042-1055, ISSN: 0264-8172

JOURNAL ARTICLE

Sephton MA, Carter JN, 2015, The chances of detecting life on Mars, PLANETARY AND SPACE SCIENCE, Vol: 112, Pages: 15-22, ISSN: 0032-0633

JOURNAL ARTICLE

Sephton MA, Jiao D, Engel MH, Looy CV, Visscher Het al., 2015, Terrestrial acidification during the end-Permian biosphere crisis?, GEOLOGY, Vol: 43, Pages: 159-162, ISSN: 0091-7613

JOURNAL ARTICLE

Sephton MA, Watson JS, Meredith W, Love GD, Gilmour I, Snape CEet al., 2015, Multiple Cosmic Sources for Meteorite Macromolecules?, ASTROBIOLOGY, Vol: 15, Pages: 779-786, ISSN: 1531-1074

JOURNAL ARTICLE

Watson JS, Sephton MA, 2015, Heat, Aromatic Units, and Iron-Rich Phyllosilicates: A Mechanism for Making Macromolecules in the Early Solar System, ASTROBIOLOGY, Vol: 15, Pages: 787-792, ISSN: 1531-1074

JOURNAL ARTICLE

Wright MC, Court RW, Kafantaris F-CA, Spathopoulos F, Sephton MAet al., 2015, A new rapid method for shale oil and shale gas assessment, Fuel, Vol: 153, Pages: 231-239, ISSN: 0016-2361

JOURNAL ARTICLE

Court RW, Sephton MA, 2014, New estimates of the production of volatile gases from ablating carbonaceous micrometeoroids at Earth and Mars during an E-belt-type Late Heavy Bombardment, Geochimica et Cosmochimica Acta, Vol: 145, Pages: 175-205, ISSN: 0016-7037

JOURNAL ARTICLE

Court RW, Sims MR, Cullen DC, Sephton MAet al., 2014, Searching for Life on Mars: Degradation of Surfactant Solutions Used in Organic Extraction Experiments, Astrobiology, Vol: 14, Pages: 733-752, ISSN: 1531-1074

JOURNAL ARTICLE

Fraser WT, Lomax BH, Jardine PE, Gosling WD, Sephton MAet al., 2014, Pollen and spores as a passive monitor of ultraviolet radiation, Frontiers in Ecology and Evolution, Vol: 2

JOURNAL ARTICLE

Fraser WT, Watson JS, Sephton MA, Lomax BH, Harrington G, Gosling WD, Self Set al., 2014, Changes in spore chemistry and appearance with increasing maturity, Review of Palaeobotany and Palynology, Vol: 201, Pages: 41-46, ISSN: 0034-6667

JOURNAL ARTICLE

Luong D, Court RW, Sims MR, Cullen DC, Sephton MAet al., 2014, Extracting organic matter on Mars: A comparison of methods involving subcritical water, surfactant solutions and organic solvents, Planetary and Space Science, Vol: 99, Pages: 19-27, ISSN: 0032-0633

JOURNAL ARTICLE

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