Petroleum surface oil seeps from a Palaeoproterozoic petrified giant oilfield

• Published in: Terra Nova
• Main Authors: Melezhik, Victor A., Fallick, Anthony E., Filippov, Michail M., Lepland, Aivo, Rychanchik, Dmitry V., Deines, Yuliya E., Medvedev, Pavel V., Romashkin, Alexander E., Strauss, Harald
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2009
• Subjects: Fennoscandia
• Online Access: http://dx.doi.org/10.1111/j.1365-3121.2009.00864.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-3121.2009.00864.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3121.2009.00864.x

Abstract Early Palaeoproterozoic rocks from the Onega Basin in Russian Fennoscandia contain evidence for substantial accumulation and preservation of organic matter (up to 75 wt% total organic carbon) with an estimated original petroleum potential comparable to a modern supergiant oilfield. The basin contains a uniquely preserved petrified oilfield including evidence of oil traps and oil migration pathways. Here, we report the discovery of the surface expression of a migration pathway, along which petroleum was flowing from the sub‐surface. This surface oil seep, the first occurrence ever reported from the Palaeoproterozoic, appears as original bitumen clasts redeposited in Palaeoproterozoic lacustrine turbidites. The δ 13 C org of clastic pyrobitumen ranges between −35.4 and −36.0‰ ( n = 14), which is within the range of interbed‐ and vein‐trapped fossil oil (−46 and −24‰), suggesting similar source. Biogenic organic matter, whose isotopic composition was modified during thermal maturation, is the likely source for the migrated hydrocarbon.