The Fur Country (1872)
Jules Verne (writer).
Read in 2020.
A two-year expedition to the Arctic, starting in 1859, is doomed by tectonic activity dislodging its fort from the Canadian mainland, leaving it floating further north. Without knowing it, the 20 men and women built it on an iceberg. Before he realizes the truth, the expedition’s astronomer is shocked to see a predicted eclipse fail to occur.
The mystery is resolved so quickly that it does not even enter Todorovian uncanny territory, but the narrative is still suggestive, like a much more realistic The Narrative of Arthur Gordon Pym of Nantucket (1838). Though the characters are weak, it’s an interesting detail that the focal leaders withhold information from their subordinates on the assumption that they couldn’t handle the stress of knowing, but the ordinary members of the expedition figure out the mystery and the fact that they are being lied to, all on their own; they react just fine; and their leaders in turn do not realize that the secret is out.
References here: The Drifting Classroom (1972).