- Sedimentary rocks: The presence of sedimentary rocks is direct evidence of ancient climatic change. The atmosphere slowly developed in its current composition from very different states related to geology and biology. Geological processes, especially weathering due to wind and rain, helped transform primary igneous rocks to sediments. Those sediments are deposited downstream, and over time they are compacted and form sedimentary rocks. Tectonic activity can also contribute to the process, acting to accelerate compaction of sediment.
- lake sediments
- ocean floor sediments
Tectonic activity has been an abundant source of carbon dioxide in the atmosphere for our earth's history. A single volcanic event can transfer as much carbon dioxide to our atmosphere as our whole nation's output for a year. This tectonic phenomenae is credited for the creation of our original atmosphere. A case can be made that the Earth's carbon is simply recycled from original volcanic origin to life forms and then later to limestone in sedimentary rock accumulations. Vast deposits of limestone are known from the Paleozoic era. Increased carbon dioxide in our atmosphere may result in an increase of limestone deposition in our oceans.
- coral reefs