Hi @bjones
There is no way at present to alter the meta title or description of those automatically generated blog listing or topic pages, unfortunately.
Fortunately, Google doesn’t really penalise duplicate content - at least not the way most people think it does - and even if it did, changing the meta data wouldn’t remove the duplication from the content of blog archive pages etc. The duplication within these pages just means they are less likely to rank well, but what would they rank well for anyway?
So in conclusion, I wouldn’t worry about it too much. If your core website pages were duplicated, that would be a much bigger problem.
Hope this helps.