Salvage is when you put back into the market goods that have economic value, only.
Archaeology is when those goods, having or having not any economical value, are considered the have archaeological value, as well - that is, they are valued for the information they contain, or are able to unlock, when considered with an archaeological perspective.
In land archaeology, when you do salvage, you are plundering and ransacking History - helas, when you do it underwater, people tend to consider that a romantic and adventurous activity.
Archaeology is when those goods, having or having not any economical value, are considered the have archaeological value, as well - that is, they are valued for the information they contain, or are able to unlock, when considered with an archaeological perspective.
In land archaeology, when you do salvage, you are plundering and ransacking History - helas, when you do it underwater, people tend to consider that a romantic and adventurous activity.