“…1). Subsequent geochemical research has led to a large body of literature dedicated to extraction methodologies, structure identification, and the distribution and diagenetic transformation pathways of various geoporphyrins (Baker and Palmer, 1978;Callot and Ocampo, 2000) found in crude oil shale, coal, bitumen, and other marine sediments (Eckardt et al, 1991;Foster et al, 2002;Gibbison et al, 1995;Huseby et al, 1996;Ocampo et al, 1992;Sheshina, 1955, 1962;Sundararaman and Boreham, 1991;Tuross and Dillehay, 1995;Van Berkel et al, 1991).…”