Mesozoic the Phanerozoic Eon, preceded by the Paleozoic ("ancient life") and succeeded by the Cenozoic ("new life"). The era is subdivided into three major periods: the Triassic, Jurassic, and Cretaceous, which are further subdivided into a number of epochs and stages. The era began in the wake of the Permian–Triassic extinction event, the largest well-documented mass extinction in Earth's history, and ended with the Cretaceous–Paleogene extinction event, another mass extinction whose victims included the non-avian dinosaurs. The Mesozoic was a time of significant tectonic, climate and evolutionary activity. The era witnessed the gradual rifting of the supercontinent Pangaea into separate landmasses
Gulf Keystone Petroleum is notably one of the largest Super Giant oilfields discovered in the last 50 years. Shaikan was declared a commercial discovery on August 1, 2012 following a five-well appraisal program. Initially independent estimates place the gross oil-in-place (OIP) volume at 13.7 billion barrels (P50) potentially making it one of the largest oilfields discovered in Iraqi Kurdistan. The oilfield covers an area of some , and comprises a series of limestone reservoirs stacked upon each other. These reservoirs encompass a very long period of geological time, from the Cretaceous which ended some 65 million years ago to the Triassic, which began