Polar forests of the Cretaceous Polar forests of the Cretaceous Cretaceous polar forests were temperate forests that grew at polar latitudes during the final period of the Mesozoic Era, known as the Cretaceous Period 145–66 Ma. During this period, global average temperature was about higher and carbon dioxide (CO) levels were approximately 1000 parts per million (ppm), 2.5 times the current concentration in Earth's atmosphere. The abundance of atmospheric carbon dioxide had a very significant impact on global climate and Earth's natural systems as its concentration is considered one of the main factors in the development of a pronounced greenhouse Earth during the Cretaceous with
The Gap (Sydney) tablet. The Gap is formed from Sydney sandstone making it part of Sydney basin. The cliff was laid as sediment more than 200 million years ago in the Triassic period. During the Jurassic era, 40 million years later, a cataclysmic event resulted in an enormous crack forming within the strata. This fault allowed erosion from wave action to create the cliff line around Sydney. Tessellated basalt rock platforms lie at the base of the cliff because The Gap is bordered to the south and west by an older sequence of largely low-grade metamorphic and granitic rocks of the Lachlan Fold