Microprobe Petrographic Thin-Section (SIMS & Raman Spot Scanner)
δ¹³C Isotope Mass Spectrometry (‰ VPDB)
Autotrophic Mat (-20 to -38‰)
Abiotic/Hydrothermal (-8 to -16‰)
Active Probe Spot
Raman Kerogen Thermometry (ID / IG)
D-Band (1350 cm⁻¹) Disorder
G-Band (1600 cm⁻¹) Graphite Order
Biogenicity & Syngeneity Verdict
Overall Biogenicity Index
94.2%
Robust 3.497 Ga Confirmed Microbial Biosignature
Mean δ¹³C Fractionation
-28.1 ‰
Abiotic Hydrothermal Prob.
5.8%
Fractionation Mechanism
Autotrophic Carbon Fixation (Calvin/Wood-Ljungdahl)
Laser Probe Coordinates & Spot Data
| ID | δ¹³C (‰) | C_org % | I_D/I_G | T_max |
|---|
Astrobiological Synthesis
Syngenetic kerogen micro-laminations within the 3.497 Ga Indian bedded chert display strong 12C enrichment (δ13C = -28.1‰), matching enzymatic Rubisco/WL autotrophy. Raman thermometry (T_max ~305–310°C) perfectly corroborates host-rock lower greenschist metamorphism, ruling out modern microbial biofilm contamination.