Jason is a reference to the sailor who traveled the Aegean (and other) seas on a quest for the Golden Fleece. Jason visited strange islands and even traveled deep into the underworld (Hades) and back again.
Other theories[]
Jason worked deep "under the world" in the mines - he eventually lived with the Others topside (into the earth and back).
Jason was probably a Black Rock sailor like Richard; neither one appears to age which suggests they may have come from the same place/people.