Not 100,000 years, but if you're looking for something that will last longer than paper, I recommend... paper. Rag paper. 100% rag, acid free copier/laser paper should be available at most office supply stores.
I'd be more worried about toner de-lamination than paper deterioration in that case.
Paper's pretty good. Not sure it's 100K years good, but you're definitely better with paper than almost anything else in the modern world. People underestimate paper.
It's vulnerable to moisture, mold and insects, though.
If you can solve problems with breakage, very little is going to compete with glass or ceramic. So, something it's hard to apply breaking force to: Maybe etch glass balls, add some impurities for visibility, then re-coat with more glass for protection. A handful of beads will survive nearly anything.
In a glass bead you could set up with the data and like a lens, i.e. the data is small and when you shine light through it it projects the information at a wall. On the other hand spheres may have the problem that they roll away; and you always need another medium (like a box) to keep them together.
An IBM researcher did this with a Tyvek-like material in the 90s, a polyester made by DuPond if I remember correctly. Just tried to google a reference but no luck.
You beat me to it. Tyvek would be an excellent candidate for its amazing durability and that it behaves much like paper (at least in terms of texture).
I'd be more worried about toner de-lamination than paper deterioration in that case.