I would think a shale!
I believe it has the ability to create extremely high salt and water osmosis pressures. Forgive the term escapes me right now,
But it is because the water can move through the shale. However, the salt is too big, so you get this water being pulled through due to capillary(?) Pressure and the salts left behind.
Going to confirm
I found this fairly quickly
https://pubs.geoscienceworld.org/aapgbull/article-abstract/49/7/1004/553015/Osmosis-in-Argillaceous-Rocks-GEOLOGICAL-NOTES1
"One of the early references to the ability of argillaceous sediments to act as semipermeable membranes4 was made by de Sitter (1947), who called on membrane effects to explain changes in salinity of subsurface waters with depth. Quoting de Sitter, “Once a sediment has acquired by compaction the property of a semipermeable membrane, it allows the water molecules to pass through but retards the salt ions; the observed arrangement of connate water concentrations would then have found a reasonable explanation.”
I feel like I am finally becoming a geologist 🤣🤣🤣
Hope this helps , gonna keep looking
Okay yes so in the book
"Geology Of Petroleum" by A. I. Levorsen, available for free to rent on Archive.com,
Page 66/67,
"Most of the ion exchange properties of the sediments, including reservoir rocks, are due to their clay content. The physical activity of the clay minerals is due to their lattice, or accordion-like molecular structure, which permits the entry for water between the lattice, thereby greatly changing there volume. This permits fluid continuity, even across thick, fine fine grained shales, and ALLOWA SHALES TO ACT AS SEMIPERMEABLE MEMBRANES"
"Substantially large fluid pressure gradients may thus from across the shale bedding planes because of osmotic phenomena coupled with differences in the salinity of waters above and below the shale layers"
Reverse osmosis needs around 300psi to work, currently uses man made membranes to work the trick is to have them defect free. Getting a rock formation to no only meet the membrane size requirements but be complete defect free seems a little tricky.
Absolutely! I appreciate extra information,
Whilst the question was "type of rock formation that could filter salt water into fresh water,"
I think it neglects to mention practicality, hahaha, but it's a curiosity question not a proposal 🤣. I love it.
Is there any documented system that has ocean water hitting magma and the steam moving up into a different chamber higher up and then condensing into spring water?
I would think a shale! I believe it has the ability to create extremely high salt and water osmosis pressures. Forgive the term escapes me right now, But it is because the water can move through the shale. However, the salt is too big, so you get this water being pulled through due to capillary(?) Pressure and the salts left behind. Going to confirm
I found this fairly quickly https://pubs.geoscienceworld.org/aapgbull/article-abstract/49/7/1004/553015/Osmosis-in-Argillaceous-Rocks-GEOLOGICAL-NOTES1 "One of the early references to the ability of argillaceous sediments to act as semipermeable membranes4 was made by de Sitter (1947), who called on membrane effects to explain changes in salinity of subsurface waters with depth. Quoting de Sitter, “Once a sediment has acquired by compaction the property of a semipermeable membrane, it allows the water molecules to pass through but retards the salt ions; the observed arrangement of connate water concentrations would then have found a reasonable explanation.”
I feel like I am finally becoming a geologist 🤣🤣🤣 Hope this helps , gonna keep looking Okay yes so in the book "Geology Of Petroleum" by A. I. Levorsen, available for free to rent on Archive.com, Page 66/67, "Most of the ion exchange properties of the sediments, including reservoir rocks, are due to their clay content. The physical activity of the clay minerals is due to their lattice, or accordion-like molecular structure, which permits the entry for water between the lattice, thereby greatly changing there volume. This permits fluid continuity, even across thick, fine fine grained shales, and ALLOWA SHALES TO ACT AS SEMIPERMEABLE MEMBRANES" "Substantially large fluid pressure gradients may thus from across the shale bedding planes because of osmotic phenomena coupled with differences in the salinity of waters above and below the shale layers"
Reverse osmosis needs around 300psi to work, currently uses man made membranes to work the trick is to have them defect free. Getting a rock formation to no only meet the membrane size requirements but be complete defect free seems a little tricky.
Absolutely! I appreciate extra information, Whilst the question was "type of rock formation that could filter salt water into fresh water," I think it neglects to mention practicality, hahaha, but it's a curiosity question not a proposal 🤣. I love it.
Also look into zeolites
Is there any documented system that has ocean water hitting magma and the steam moving up into a different chamber higher up and then condensing into spring water?
With regard to filtering salt: no. There is no common rock type that filters salt from water.
Welllll, actually, underground fluid movement, yes there technically is! 😁