γ-Carotene has tentatively been identified as a biomarker for green and purple sulfur bacteria in a sample from the 1.640 ± 0.003-Gyr-old Barney Creek Formation in Northern Australia which comprises marine sediments.

[2] Tentative discovery of γ-carotene in marine sediments implies a past euxinic environment, where water columns were anoxic and sulfidic.

Unlike β-carotene which occurs across a vast array of lineages in all three domains of life, γ-carotene is constrained to only a very few potential precursors.

[11] Gas chromatography-mass spectrometry (GC/MS) is an analytical technique in geochemistry widely employed to identify and quantify organic compounds present in sedimentary rocks.

[12] The results from isotope ratio mass spectroscopy and GC/MS can accurately discriminate the presence of γ-carotene in an extraction from a sedimentary sample.

The identification of γ-carotene through these methods would provide a compelling indication of a past euxinic environment, where water columns were anoxic and sulfidic.