Oceanic basin an active - and growing - oceanic basin include an elevated mid-ocean ridge, flanking abyssal hills leading down to abyssal plains. The elements of an active oceanic basin often include the oceanic trench associated with a subduction zone. The Atlantic ocean and the Arctic ocean are good examples of active, growing oceanic basins, whereas the Mediterranean Sea is shrinking. The Pacific Ocean is also an active, shrinking oceanic basin, even though it has both spreading ridge and oceanic trenches. Perhaps the best example of an inactive oceanic basin is the Gulf of Mexico, which formed in Jurassic times and has
Bonaparte Basin over thick under the ocean. The basin originated from the Cambrian period to the Cenozoic era, 540 to 360 million years ago. Limestone, sandstone, mudstone, basalt, coal and glacial sediments are embedded in the basin. It contains several oil and natural gas fields amounting to 18% of Australia's known reserves of natural gas. Total estimated reserves are of oil and of gas. The sedimentary basin partially overlays the Kalkaindji province, the Birrindudu Basin and Wolfe Basin. The Bonaparte Basin has deposits of lead, zinc, iron, gold and smaller coal deposits on land, mineralised in sandstone deposits. There were studies on