Earth Science · Geology · Earth Interior / Principles and Exploration
Magma cooling and crystal size — principles and investigation
The rate at which magma cools affects the time crystals can grow and the rock texture. Compare the changes in the number and size of crystals by varying the cooling rate and initial temperature. It links the fast-cooling fine-grained texture with the slow-cooling coarse-grained texture, but does not interpret rock type as being determined solely by cooling rate.
How does it work?
Fast cooling schematically shows the characteristics of a basalt-type fine-grained structure, and slow cooling shows the characteristics of a granite-type coarse-grained structure.
Nucleation rate = 3v, growth amount ∝ residence time in crystallization section
Try this investigation
- Select the cooling speed and run. Observe the process of small nuclei forming and growing in the red molten body. Observation is carried out at the stomach speed.
- At the initial temperature of 1200 ℃, 10 ℃/s and 1 ℃/s are recorded. Compare crystallization retention time, number, and average size.
- Add an intermediate condition of 5°C/s to check the relationship between cooling rate and virtual crystal size.
Interpreting your results
Why does slow cooling produce large crystals in this model?
Growth time becomes longer in the crystallization zone of 1000~700℃. With a fixed 10 s nucleation window, the nucleation rate is proportional to the cooling rate.
Assumptions and limitations
It's a virtual rule. Set the 1000~700 ℃ range and a 10 s nucleation window after entry, set the nucleation rate at 3v units/s and the linear growth rate at 0.02 relative unit/s. We omit decision conflict, growth competition, and chemical composition. We do not predict the actual mineral type, rock, or crystal size.