Various aboriginal cultures (there isnt just one) have elements which are much older but over 300 of the ~400 languages are from one family (pama nyungyan). This family's common ancestor is traced to a region in North Australia around 5000 years ago. These languages suddenly exploded and spread across the continent at around the same time other technologies and techniques seem to change. This was around the time of the Dingo introduction and this considerable Indian introgression discussed in paper--the dingo was probably brought by these people. I may have misremembered that these languages have some relation to south indian ones, it seems this is disputed, but this is all happening around the same time. There is a lot that isn't known about Aboriginal peoples and the genetic studies once they are performed (if allowed) are likely going to show a more complex picture than the usual narrative. To the person who called me a tamil nationalist or something i can only laugh.