Showing papers in "AAPG Bulletin in 2022"

A very unconventional hydrocarbon play: The Mesoproterozoic Velkerri Formation of northern Australia

Abstract: The ca. 1.5–1.3 Ga Roper Group of the greater McArthur Basin is a component of one of the most extensive Precambrian hydrocarbon-bearing basins preserved in the geological record, recently assessed as containing 429 million barrels of oil and eight trillion cubic feet of gas (in place). It was deposited in an intra-cratonic sea, referred to here as the McArthur-Yanliao Gulf. The Velkerri Formation forms the major deep-water facies of the Roper Group. Trace metal redox proxies from this formation indicate that it was deposited in stratified waters, in which a shallow oxic layer overlay suboxic to anoxic waters. These deep waters became episodically euxinic during periods of high organic carbon export. The Velkerri Formation has organic carbon contents that reach ~10 wt%. Variations in organic carbon isotopes are consistent with organic carbon enrichment being associated with increases in primary productivity and export, rather than flooding surfaces or variations in mineralogy. the Formation an intracontinental setting recent global reconstructions show a broader mid to low latitude gulf, with the Formation coeval of

The West Siberian Super Basin: The largest and most prolific hydrocarbon basin in the world

Abstract: ON COVER – Charles Sternbach (left), Linda Sternbach (center), and John Underhill (right) atHutton’s unconformity, Siccar Point. Locatedon the East Lothian coast of Scotland, the unconformity represents the tectonicmegasequence boundary separating the lower Paleozoic metasediments from upper Paleozoic, red Devonian breccias and conglomerates, the significance of which is described by Underhill and Richardson’s paper on the North Sea Rift Super Basin on p. 573 of this issue of the Bulletin. Photograph by Vrachliotis Stavros. I NTRODUCT ION