Table 1 Identification of the morphological groups through the ToF–SIMS molecular distribution found in the Upper Gossan sample of Peña de Hierro.
Group | Microstructure | Potential compounds | Target area (TA) | |
|---|---|---|---|---|
m/z positive ions | m/z negative ions | |||
Group 1 | Loosely to densely packed networks of < 50 micron thick filaments with strong mineralization shown by positive and negative sulfur-bearing ions | Lineal hydrocarbons fragmented and ionized from long lipids which form adducts with NH4+ likely sphingolipids | Fatty acids coming from lipidic structures like ceramides | TA1, TA2, TA3 |
Salt composition of mineralized structures | SOx-bearing adducts of cholesterol-like sterols and lipids coming from the mineralized surface of fungal structures | |||
Group 2 | Linear elements with an average thickness of > 80 microns disassociated from the other microstructures | Likely terpenoid fragments sourced in plants | TA1 | |
Group 3 | Ovoidal microstructures averaging 60 microns (TA1 and TA2); following larger microstructures and the mineral matrix in TA3 | Fragments of amino acids and peptides. The occurrence of some ions in the TA3 matrix while others follow the biological microstructures suggest different a origin for them | TA1, TA2, TA3 | |
Group 4 | Two coupled elongated nodular microstructures in which the elongation axes connect both nodule centers (TA1); occurring as an empty cast in TA3 | Unknown origin | n/a | TA1, TA3 |
Group 5 | 600 micron-long elongated triangle-like morphology crosscutting the main structure fabric of Groups 1 and 2; occurring as an empty cast in TA3 | Plant terpenoids like piperonal derivatives | TA1, TA3 | |
Group 6 | Three 120-micron subcircular morphologies show an empty central void; occurring as an empty cast in TA3 | Vanillic acid derivatives | n/a | TA1, TA3 |
Group 7 | 10- to 50-micron micronodules following the main pattern appearing in Groups 3 and 4 | Plant terpenoids | TA1 | |
Group 8 | Structures with short branches with an average length of 200 microns that are transverse to the fabric of Group 1 | n/a | Tannins, or some polysaccharides | TA1 |
Group 9 | Densely packed network of 40-micron-long filament-like microstructures, which appear in TA2 along the sharp boundary that contacts Group 1; fits the primary microstructure found in TA3, while in the TA1 show a more homogeneous occurrence | Glycerolipids and glycerophospholipids with possible occurrence of glycerophosphocholines. Fatty acids fragmented from the lipidic structure. Abundant in TA2 and TA3, and secondary in TA1 | TA2, TA3 | |
