The abnormal distribution of the molecular fossils in the pre-Cambrian and Cambrian: its biological significance

Multiple-sourced features of marine oils in the Tarim Basin, NW China – Geochemical evidence from occluded hydrocarbons inside asphaltenes

“…Due to their different depositional environments and organic matter input, oils derived from each suite of source rocks have different biomarker fingerprints. Oils from the Cambrian-Lower Ordovician source rocks contain abundant C 30 dinosteranes, Gammacerane, and C 28 regular steranes, but a low concentration of diasteranes (Zhang et al, 2002b;2004a;Wang and Xiao, 2004;Ma et al, 2006;Cai et al, 2009a). These are represented by oil from TD2 in the Cambrian reservoir and Tz62 in the Silurian reservoir (Xiao et al, 2005;Tang and Wang, 2007).…”

“…These are represented by oil from TD2 in the Cambrian reservoir and Tz62 in the Silurian reservoir (Xiao et al, 2005;Tang and Wang, 2007). By contrast, oils derived from the Middle-Upper Ordovician source rocks, such as Ym2 oil (Li et al, 2010a), have different characteristics, with low content of C 30 dinosteranes, Gammacerane, and C 28 regular steranes but relatively abundant diasteranes (Zhang et al, 2002b;2004a;Wang and Xiao, 2004). C 28 regular steranes were thought to originate mainly from diatoms, coccolithophores and dinoflagellates, which were important organic input for the Cambrian-Lower Ordovician source rocks.…”

Oil–source correlation for the paleo-reservoir in the Majiang area and remnant reservoir in the Kaili area, South China

“…It is commonly accepted that triaromatic steroid hydrocarbons are the products of steranes aromatization and derived from marine Acritarchs whose precursor was Dinophyceae (Liang and Chen, 2005;Zhang et al, 2002;Peters et al, 2005c). Triaromatic steroid hydrocarbons are the kind of biomarkers with highest bioresistance to severe biodegradation (Peters and Moldowan, 1993a).…”

Oil-source correlation of Lower-Triassic oil seepages in Ni’erguan village, Southern Guizhou Depression, China

“…The long chain triaromatic steroids (C 26 -C 28 -triaromatic steroid) could have originated from marine Acritarchs (Zhang et al 2002;Peters et al 2005). The distribution of long chain triaromatic steroids can reflect the original organic input (Ludwig et al 1981;Mackenzie et al, 1982).…”