Accelerated Solvent Extractor Accelerated Solvent Extractor

The ASE extracts solid and semisolid samples with liquid solvents at elevated temperatures and pressures for increased efficiency.

Gas Chromatographs Gas Chromatographs

Gas chromatography is the main technique we use to separate out the individual components of very complex mixtures.

High Resolution Mass Spectrometer High Resolution Mass Spectrometer

The autospec combines the separating power of gas chromatography with the sensitivity of mass spectrometric detection.

Isotope Ratio Mass Spectrometer Isotope Ratio Mass Spectrometer

Stable isotope analysis for many different types of substances—organic matter, carbonates, gases and individual organic compounds.

Agilent 6000 Series HPLC-MS Agilent 6000 Series HPLC-MS

High Pressure Liquid Chromatography separates compounds, a Quadrupole Time-of-Flight mass spectrometer identifies lipids.

Lab Tour Lab Tour

Click here to venture on a virtual, photographic tour of the Summons lab, its facilities, and instruments.

Depositional environment Typical biomarker patterns Reference example
marine 24-n-propylcholestane Moldowan et al., 1985
lacustrine botryococcane and other biomarkers of Botryococcus (fresh to brackish water) elevated concentrations of C30 tetracyclic polyprenoids (fresh to brackish water) Metzger and Largeau, 1999 Holba et al., 2003
hypersaline C21 to C25 regular isoprenoids enriched in 13C relative to biomarkers of phytoplanktonic origin, high gammacerane1 Grice et al., 1998b Sinninghe Damste et al., 1995
terrestrial organic matter input diverse biomarkers of higher plants Summons and Brocks, Treatise on Geochemistry
strongly anoxic conditions (water column anoxia?) 28,30-dinorhopane, 25,28,30-trisnorhopane, gammacerane1 Peters and Moldowan, 1993 Sinninghe Damste et al., 1995
photic zone euxinia2 isorenieratane, 2,3,6- and 2,3,4- trimethylarylisoprenoids, chlorobactane, Me, isobutyl maleimide Grice et al., 1996a, Hartgers et al., 1993, Koopmans et al., 1996a, Summons and Powell, 1987
carbonates and evaporites low diasterane/sterane ratios1 van Kaam-Peters et al., 1998
high 2a-methylhopane concentrations1 Summons et al., 1999
high 30-norhopanes1 Subroto et al., 1991

1 Typical for, but not necessarily restricted to, this depositional environment

2 This might include environments with an anoxic and sulfidic water column that persists into the photic zone, or microbial mats in very shallow water settings that become anoxic within millimeters below the sediment water interface


Chart adapted from Treatise on Geochemistry Review, Chapter 8, Summons and Brocks