Should we close Questions as duplicates of old, unanswered Questions?

Question

While I was going through the close review queue today, I saw that this question has been marked as a duplicate of this question from two months ago.

The old question does not have an accepted answer, (though it has one useful answer) and marking the new question as an duplicate of the old question will not be fruitful as probably no one will answer the old question, and this topic will go unanswered.

I would instead propose that the old question be marked as a duplicate of the new, or both of them merged if possible.

What should generally be done in a case like this?

Answer 1

Regarding the question title:

Should we close Questions as duplicates of old, unanswered Questions?

It is not possible anymore to mark a question as a duplicate, without the older/original thread having an upvoted or accepted answer on it. See here.

2013-02-01: The "close as duplicate" process has been updated: the interface to search for duplicate questions has been improved, and users may no longer vote to close questions as duplicates of questions that do not have an upvoted or accepted answer

About choosing which question should be considered original and which ones should be duplicates when all of them have upvoted (or accepted) answers, refer to this GIS meta thread.