[PalmTree]

Interesting article on enormous reservoir of freshwater trapped beneath the seabed off of the East Coast. Supposedly it is 20,000 years old. Several theories as to how it got there, it was first posited in the 1980s. Indications are very low salinity about 110 miles offshore of Long Island.

Pleistocene hydrogeology of the Atlantic continental shelf, New England | GSA Bulletin | GeoScienceWorld

They sampled sites 20-30 miles off the coast of Massachusetts, drillign down 1,300 feet where there's a seal that prevents salty water from mixing with the fresh water.

Enormous freshwater reservoir discovered off the East Coast may be 20,000 years old and big enough to supply NYC for 800 years

Makes me wonder if there are similar reservoirs off of the West Coast.

I'd venture a guess that it'd be much less likely off for similar reservoirs to have formed off the west coast. The western margin's an active subduction zone with the Pacific plate more rapidly (geologically speaking) expanding ever-eastward and under the North American plate, so there's a) a larger topographic dropoff offshore and b) less chance for the slow sedimentary environment that favors the reservoir formation in the relatively passive eastern continental shelf, as described in the article, to occur.  I can't really venture a guess as to possible availability of similar extraordinary hydrologic sources for the resevoir (i.e. Pleistocene rainfall and subglacial runoff) as described in the GSA article either.

That said, I wound up with more coursework in hard rocks (igneous, metapmorphic) than soft (sedimentary) as an undergrad, so I'll never say never....

[PalmTree]

Interesting article on enormous reservoir of freshwater trapped beneath the seabed off of the East Coast. Supposedly it is 20,000 years old. Several theories as to how it got there, it was first posited in the 1980s. Indications are very low salinity about 110 miles offshore of Long Island.

Pleistocene hydrogeology of the Atlantic continental shelf, New England | GSA Bulletin | GeoScienceWorld

They sampled sites 20-30 miles off the coast of Massachusetts, drillign down 1,300 feet where there's a seal that prevents salty water from mixing with the fresh water.

Enormous freshwater reservoir discovered off the East Coast may be 20,000 years old and big enough to supply NYC for 800 years

Makes me wonder if there are similar reservoirs off of the West Coast.

I'd venture a guess that it'd be much less likely off for similar reservoirs to have formed off the west coast. The western margin's an active subduction zone with the Pacific plate more rapidly (geologically speaking) expanding ever-eastward and under the North American plate, so there's a) a larger topographic dropoff offshore and b) less chance for the slow sedimentary environment that favors the reservoir formation in the relatively passive eastern continental shelf, as described in the article, to occur.  I can't really venture a guess as to possible availability of similar extraordinary hydrologic sources for the resevoir (i.e. Pleistocene rainfall and subglacial runoff) as described in the GSA article either.

That said, I wound up with more coursework in hard rocks (igneous, metapmorphic) than soft (sedimentary) as an undergrad, so I'll never say never....