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Research Paper: Degassing of early-formed planetesimals restricted water delivery to Earth

Isn't the water in Saturn's rings from the same source (i.e. the same isotope ratio)?

I was trying to figure out the difference between, “unmelted” and “not melted.” At first it looked like a typo.

For clarity, the water appears to come from unmelted materials and not from melted materials.

Essentially achondrites are melted materials, all produced by melting of their parent bodies such as differentiated planetesimals and differentiated planetary bodies, like the Moon or Mars. Chondrites, on the other hand, have experienced no significant melting as they are pre-planetary rocks, or the building blocks of planets. The implication of this paper then is that Theia (the giant impactor hypothesis that leads to the formation of the moon) could not have delivered water to the early Earth.

Deuterium to hydrogen ratios relative to Earth's Standard Mean Ocean Water (SMOW) values for Ring B, and Titan are relatively close though Enceladus and Phoebe greatly differ. Still, CI chondrite D/H ratios are closer to Earth's than any of Saturn's rings or moons.