The composition of the soluble organic matter of the Oxfordian–Kimmeridgian Flodigarry Shale Member (Isle of Skye, Scotland) is presented for the first time. A continuous succession of silty clays and nodular limestone beds is exposed on a rocky shore to the north of Staffin Bay. This succession is proposed as a potential stratotype of the boundary between the Oxfordian and Kimmeridgian stages. This paper points out the exceptional preservation and very low thermal degradation of the organic matter. Indeed, the molecular composition is characterized by the abundance of unsaturated biomarkers (hopenes and diasterenes) as well as undamaged bioterpenoids (ferruginol and sugiol). The abundance of long-chain n-alkanes characterized by an odd-over-even predominance reveals a dominant continental contribution. This is also attested to by the relatively high amounts of plant biomarkers (e.g. ferruginol, sugiol, cadalene and retene), which suggest a palaeovegetation largely composed of pinophytes, especially Cupressaceae, Taxodiaceae and Cheirolepidiaceae, on the nearest emerged lands. The water column of the depositional environment was oxic in its upper part and rather dysoxic in its lower part. The composition of the organic matter does not significantly change along the Flodigarry Shale Member. In other words, no evolutionary events or drastic change in palaeoenvironments can be deduced from the molecular content of these sedimentary rocks, and it does not allow us to support a precise location for the Oxfordian/Kimmeridgian boundary in the succession.

The search for organic molecules and traces of life on Mars has been a major topic in planetary science for several decades. 26 years ago Viking, a mission dedicated to the search for life on Mars, detected no traces of life. The search for extinct or extant life on Mars is the future perspective of several missions to the red planet, for example Beagle 2, the lander of the Mars Express mission. In order to determine what those missions should be looking for, laboratory experiments under simulated Mars conditions are crucial. This review paper describes ongoing experiments that are being performed in support of future Mars spacecraft missions. Besides the description of the experiments, the experimental hardware and set-up, this paper also gives the scientific rationale behind those experiments. The historical background of the search for life on Mars is outlined, followed by a description of the Viking Lander biology and molecular analysis experiments and their results, as well as a summary of possible reasons why no organic compounds have been detected. A section concerning organic compounds in space and related experiments discusses the organic molecules we will use in simulation experiments. The set-up is discussed briefly in the following section. We conclude with an overview of future missions, stressing the relation between these missions and our laboratory experiments. The research described in this article has been developed as part of a Mars Express Recognized Cooperating Laboratory (RCL), and for planned future Mars missions such as the PASTEUR lander.