oligocene [ˈɑlɪɡoˌsin, ˈolɪ-]

例句:

• Oligocene erosion had truncated the sediments draped over the dome.
  覆盖于穹丘上的沉积岩为渐新世侵蚀所截削.
  
• Beibu Wan Basin was a lake in the middle Eocence - Lower Oligocene.
  北部湾 盆地在中始新世至早渐新世是一个湖泊.
  
• There are four hydrocarbon source rocks, Palaeocene, Eocene, Oligocene and Miocene.
  西湖凹陷发育古新统 、 始新统 、 渐新统及中新统四大烃源岩系.
  
• Proboscideans diversified during the Eocene and early Oligocene.
  来自BBC
• But the amount of carbon dioxide in the atmosphere has reached levels not seen for millions of years prior to the Oligocene.
  来自SA