Spectral narratives of microstructural restyling and their controls on hydrocarbon generation potential from coal

Abstract The low to medium-rank Tertiary coals from Meghalaya, India, are explored for the first time their comprehensive microstructural characterization using FTIR and Raman spectroscopy. Further, results these compared with Permian medium high-rank understand restyling during coalification its controls on hydrocarbon generation. coal samples grouped based mean random vitrinite reflectance values record transformations in spectral attributes increasing rank. aliphatic carbon apparent aromaticity respond sharply jump ( $${\bar{\rm R}}$$ R ¯ r : 0.50%) transition anchizonal metamorphism of coals. Moreover, band intensity ratio changes but remains invariable turns subtle again onset pregraphitization coals, revealing a polynomial trend metamorphism. Rock–Eval hydrogen index genetic potential also decline at jump. Besides, an attempt comprehend reveals that comprise highly reactive functionalities type II-S kerogen, along paleotemperature (74.59–112.28 °C) may signify generate early-mature hydrocarbons. However, presence II-III admixed lesser abundance moieties, overall moderate (91.93–142.52 imply mixed potential. Meanwhile, metamorphism, polycondensed aromatic microstructure, high (~ 334.25 ~ 366.79 indicate negligible producing any