TITLE:
Organic Geochemical Analysis of Oil Inclusions in Quartz Collected from Afghanistan and Pakistan
AUTHORS:
Shigenori Ogihara
KEYWORDS:
Alkylbenzenes, Double-Terminated Quartz, Fluorescence, Oil Inclusion, Oil Quartz
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.16 No.12,
December
30,
2025
ABSTRACT: This study conducted organic geochemical analyses of oil inclusions in quartz samples collected from Afghanistan and Pakistan. Samples from both countries contained large amounts of n-alkanes; however, sterane, triterpane, and isoprenoid hydrocarbons were not detected. Small amounts of iso- and anteiso-alkanes as well as alkylcyclohexanes were identified. The individual carbon isotope compositions of n-alkanes showed different trends between the two sample sets. The fluorescent compounds were separated into the polyaromatic hydrocarbon (PAH) fraction. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that alkylbenzenes, particularly ethylbenzene, were the major components in the PAH fraction. The fluorescence observed in the oil-bearing quartz was attributed to the presence of alkylbenzenes.