Karoo Ice Age
The Karoo Ice Age ( 360-260 million years ago ) was the second major ice age of the Phanerozoic. It is named after the found in the Karoo in South Africa glacial deposits, which represented the first clear evidence for this ice age.
The tectonic amalgamation of continents Euramerica ( later with the Ural orogeny to Laurasia ) in and Gondwana to Pangaea, in the Variscan orogeny created a large continental land mass in the Antarctic region, and the disappearance of Rheischen ocean or of Iapetus interrupted the warm ocean currents the Panthalassa and Tethys Sea, which had progressive slowdown in the summer and snow accumulated result. This in turn led to the growth of glaciers in the mountains, which then spread out over the highlands and also a ice sheet formed which covered a relatively large part of Gondwana.
At least two major periods of glaciation have been discovered:
- The first glaciation period falls into the Mississippian ( 359.2 to 318.1 million years ago ): The ice sheets spread out from a core in what is now southern Africa and South America.
- The second freezing period falls into the Pennsylvanian ( 318.1 to 299 million years ago ); The ice sheets spread out from a core in today's Australia and India.
The extent of the glaciers of Antarctica is not known exactly due to the existing ice sheet.
Follow the Karoo Ice Age
The impact of the Karoo Ice Age begin the Dwyka glaciation before around 300 to 280 million years. At this time, today Namibia was in the area of the South Pole. The Inlandseismassen can be obtained by tillites ( solidified moraines ) and the sandstones and shale formed from sediments occupy. In the following dry season Dwykagebiet was spilled by Able Wrestled, called Etjo or Ecca. This phase ended with the breakup of Gondwana and the subsequent drift of South Africa approximately 132 million years ago. The thus created up to two kilometers mighty Etendeka flood basalts preserved the pre-existing Dwyka relief. Weathering and erosion of the underlying land surface reappears.
In the period of the Karoo Ice Age there was an increased oxygen concentration in the atmosphere that encouraged the plants in the warmer areas to an increased metabolism. This resulted in an increased growth in the Carboniferous age and the development of large vertebrates or insects such as the giant dragonfly Meganeura or the centipede Arthropleura.