Sorry for the delay. Distracted by thunderstorms and general torpor.
(CdM) Not sea-level
(Tuj) Despite the above remark, NO
(Bis) NOT Radio Caroline
(SM) NOT Al futures
(Tuj) NOT fictional but maybe uncommon.
(Raak) NOT scientific
(CdM) Mineral connection NOT liquid.

(Raak) Already answered that. See Tuj (above). Still not fictional.
(CdM) NO. Could be anywhere (on earth).
(SM) YES, could be, but not its most common use.

(SM) NOT geology
(Raak) Very probably the answer is YES but strictly it doesn't have to be.

(CdM) Magnetism? NO
(RTG) Radioactive? NO.