11. There just was not enough algae to create source rocks . 12. Nugaal Valley Block has been identified as having reservoir, source rock and trap potential. 13. The predominant source rock in the Zonguldak basin is coal. 14. Following the Burgan Formation, the Mauddud Limestone Formation ( source Rock ) began forming. 15. Buried source rocks beneath the deepest depocenters may be overmature. 16. A good source rock for hydrocarbons can contain up to twenty percent organic carbon. 17. The Cretaceous shale is also identified as the probable source rock for the Columbus basin. 18. Other locally sourced rock used in tool production included jaspers for hammerstones and sandstone grinders. 19. Many of the Phosphoria shales are rich in organic matter and are petroleum source rocks , 20. To the west, calcareous source rock that was once marine, produces brown soil containing calcareous pebbles.
