Title: TOF-SIMS analysis of polycyclic aromatic hydrocarbons in Allan Hills 84001 Authors: Stephan, T.; Jessberger, E. K.; Heiss, Ch. H.; Rost, D. Publication: Meteoritics & Planetary Science, vol. 38, no. 1, p.109-116 Publication Date: 01/2003 Origin: M&PS Bibliographic Code: 2003M&PS...38..109S Abstract The presence of polycyclic aromatic hydrocarbons (PAHs) in the Martian meteorite Allan Hills 84001 (ALH 84001) was considered to be a major sign of ancient biogenic activity on planet Mars (McKay et al. 1996). An asserted spatial association of PAHs with carbonates, carriers of so- called nanofossils, was crucial for their suggested connection to early life forms. Although both observations can be explained individually without employing living organisms, a lateral correlation of PAHs and carbonates would suggest a genetic link between PAHs and the microstructures, favoring a biogenic explanation. On the other hand, without such a correlation, a biogenic or even a Martian origin of the PAHs cannot be inferred. Here we show that there is no correlation of PAHs and carbonates in ALH 84001. Furthermore, a general trend of high PAH concentrations at locations where terrestrial lead is present obviously suggests a terrestrial origin for PAHs in ALH 84001. Title: Polycyclic Aromatic Hydrocarbons in Allan Hills 84001: A Result of Terrestrial Contamination? Authors: Stephan, T.; Jessberger, E. K. Publication: Meteoritics & Planetary Science, vol. 35, Supplement, p.A152 Publication Date: 07/2000 Origin: LPI Bibliographic Code: 2000M&PSA..35R.152S Abstract Not Available Title: Polycyclic Aromatic Hydrocarbons in Allan Hills 84001 - Implications from Time-of-Flight Secondary Ion Mass Spectrometry Analyses Authors: Stephan, T.; Jessberger, E. K. Publication: 31st Annual Lunar and Planetary Science Conference, March 13-17, 2000, Houston, Texas, abstract no. 1326 Publication Date: 03/2000 Origin: LPI Bibliographic Code: 2000LPI....31.1326S Abstract Not Available Title: Polycyclic Aromatic Hydrocarbons in Meteorites: Allan Hills 84001, Murchison, and Orgueil Authors: Stephan, T.; Heiss, C. H.; Rost, D.; Jessberger, E. K. Publication: 30th Annual Lunar and Planetary Science Conference, March 15-29, 1999, Houston, TX, abstract no. 1569 Publication Date: 03/1999 Origin: LPI Bibliographic Code: 1999LPI....30.1569S Abstract Relative abundances of different PAHs in TOF-SIMS spectra from Murchison and Orgueil resemble those from ALH 84001. They don't show indications for heterocycles or alkylation as expected for biogenic PAHs. A similar, non-biogenic origin is deduced. Title: Polycyclic Aromatic Hydrocarbons are Everywhere in Allan Hills 84001 Authors: Stephan, T.; Rost, D.; Jessberger, E. K.; Greshake, A. Publication: Meteoritics & Planetary Science, vol. 33, p. A149 Publication Date: 07/1998 Origin: LPI Bibliographic Code: 1998M&PSA..33R.149S Abstract Not Available Title: Polycyclic Aromatic Hydrocarbons in ALH 84001 Analyzed with Time-of-Flight Secondary Ion Mass Spectrometry Authors: Stephan, T.; Rost, D.; Jessberger, E. K.; Greshake, A. Publication: 29th Annual Lunar and Planetary Science Conference, March 16-20, 1998, Houston, TX, abstract no. 1263. Publication Date: 03/1998 Origin: LPI Bibliographic Code: 1998LPI....29.1263S Abstract Not Available Title: The Lateral Distribution of Polycyclic Aromatic Hydrocarbons in Allan Hills 84001: Implications for Their Origin Authors: Stephan, T.; Rost, D.; Heiss, C. H.; Jessberger, E. K.; Greshake, A. Affiliation: AA(Westfaelische Wilhelms Univ.), AB(Westfaelische Wilhelms Univ.), AC(Westfaelische Wilhelms Univ.), AD(Westfaelische Wilhelms Univ.), AE(Museum fuer Naturkunde) Publication: Workshop on the Issue Martian Meteorites: Where do we Stand and Where are we Going?, p. 50 Publication Date: 01/1998 Category: Lunar and Planetary Exploration Origin: STI NASA/STI Keywords: CARBONATES, MICROORGANISMS, ORGANIC MATERIALS, POLYCYCLIC AROMATIC HYDROCARBONS, EXOBIOLOGY, EXTRATERRESTRIAL LIFE, SNC METEORITES, MICROANALYSIS, SECONDARY ION MASS SPECTROMETRY Bibliographic Code: 1998mmws.work...50S Abstract Polycyclic aromatic hydrocarbons (PAHs) in ALH 84001 were considered to be evidence for relic biogenic activity on Mars. Crucial for their proposed connection to early life forms is a suggested spatial association with carbonates that contain internal structures resembling terrestrial microfossils. Although each observation can be explained individually a lateral correlation would suggest a genetic link between PAHs and the microstructures. Crucial for the investigation of spatial associations is the lateral resolution of the applied analytical methods. In the mentioned studies, microprobe two-step laser mass spectrometry (microL2MS) was used for the analysis of PAHS. With this technique, an unambiguous determination of a spatial association is limited by its lateral resolution, about 50 micrometers, a size that is comparable with the typical dimension of the carbonate globules. Scanning transmission X-ray microscope (STXM) C mapping and X-ray absorption near-edge structure (XANES) spectroscopic measurements on carbonates from ALH 84001 indicated the presence of organic C (pi-bounded C) within or associated with carbonate globules on the scale of approximately 100 nanometers. A definite identification of the nature of this organic C, which seems to be locally present at percent levels, is not possible with these techniques. Only a small fraction, less than 1 percent of wt, of the organic material in this meteorite may actually be represented by PAHS, and there is isotopic evidence favoring a terrestrial origin for the majority of organic matter in ALH84001