How Deep Would the Mariana Trench Need to Be for Ice VII to Form?

[Calpalned]

Homework Statement

**This thread could also belong to the chemistry forum**
*This isn't an actual homework problem, but it is a simple question, so I put it here in the homework forum. I am under the impression that the physics forum is for more advanced questions*
How deep would an ocean on Earth have to be for ice VII to form? It forms under 3 GPa of pressure at room temperature (20 C).

Homework Equations

N/A

The Attempt at a Solution

I am only asking this question because I am curious how the Mariana Trench compares. At the bottom of the Mariana Trench, the pressure is 110 MPa. $\frac {3} {t} = \frac{3GPa}{110MPa}$ = 27.27. So the Mariana Trench needs to be 27 times deeper. Is this correct (if the temperature is assumed to be a constant ?

 

[Bystander]

Give or take corrections for compressibility of sea water, looks good enough. Depth of Mariana Trench isn't a particularly standard unit of length, so you might consider turning that into meters or kilometers, but that's nitpicking.