A natural oil seep in the floodplain of the Amga River (Siberian Platform)

A natural oil seep has been revealed in the floodplain of the middle stream of the Amga River, in zone of the exposure of Middle Cambrian sediments. A distinctive feature of saturated hydrocarbons of this oil is the absence of 12- and 13-methylalkanes, biomarkers that are present in oils of the Vendian–Cambrian deposits of the Nepa–Botuobiyan petroliferous province. In this feature the studied seep oil is similar to the Middle Cambrian oil from hydrogeologic wells (1-P and 1-T) drilled earlier downstream of the Amga River.