I just ran through the calculations of the types of pressures that are typical at the deepest parts of the ocean. Using the equation: pressure = density * gravity * depth, I determined that at Mariana Trench (the deepest part of the ocean) there are hydrostatic pressures on the order of 0.11 GPa. Upon review of water’s (I couldn’t find one for salt water) pressure-temperature phase diagram, I noticed that pressures of about 0.30 GPa should result in solidification of water at approximately 4 degrees C. I realize that due to impurities (eg. salt) the water phase diagram does not exactly represent what’s going on here, but I am assuming its pretty close. Anyways, the 0.11GPa seems too close to 0.30GPa for it not to ever occur in nature (because theory never exactly predicts practice, as we all know!). Have there ever been any ice crystals located deep under the ocean’s surface???
I meant seawater, I’m too worried about seaater - although I’m sure seaater is a major problem!!
You do realize that you’re talking a pressure difference of around 28,500 psi between the pressure in the Mariana Trench and the point at which water freezes at 4 degrees C, right? It is extremely unlikely that anything would produce a pressure spike quite that high. And adding salt to the water can dramatically lower its freezing point.
Methane ices are common along the fringe of the continental shelves. They are a mix of methane and water. Highly unstable, they can easily go gaseous.
Well, what’s the temperature at that depth?
In deep mines the temperature is fairly high. The Marianas Trench is certainly geologically active (Guam gets a few mild earthquakes per year.) Is it really that cold down there?
I remember an old article discussing the role of internal heating in keeping the atmosphere warm, where the quoted figure for surface temp without the sun was suprisingly high (20 degrees F, I think.)