We often see siliceous oozes below the calcite compensation depth (CCD). How is this possible?
This occurs due to the movement of oceanic plates. Siliceous oozes can accumulate above the CCD but as the plate moves within an ocean basin it is possible for the ooze to be transported into deeper water, and covered by abyssal clay, which will prevent its dissolution.
The earth is approximately 4.5 billion years old, however the oldest tectonic plates we see are approximately 200 million years old. How is this possible?
Tectonic plates are continually being created at spreading centers (divergent boundaries) and recycled at subduction zones (convergent boundaries). Therefore, plates that previously existed have been recycled continually since the birth of our planet.
We all know plants need water, but what exactly is it used for?
Plants actually need water to provide them with electrons to replace those lost in the process of photosynthesis. As photosystem II sends excited electrons to photosystem I, the splitting of water replenishes those lost electrons, and in the process releases the oxygen (O2) that we breath.