3. Materials and methods
3.1. Samples
Sandstones and mudrocks were collected from oil exploration
drillcore (n=133) and surface outcrop (n=72) in the northeastern
Sylhet basin (Fig. 1). Core samples (n=33) from the Renji, Bhuban and
Bokabil Formations were selected for petrographic analysis, and all core
samples and 34 outcrop samples were subjected to geochemical study