Time traveller story set in Australia where the ending is determined with a roll of the dice

Question

I'm looking for the title and the author of a young adult book set in Australia. I read this in the 1980s or 1990s so it was published before 2000 and took place

I do not remember the overall arc of the plot, but I remember some specific story details:

• The book takes place in Australia in the 1970s, 1980s or 1990s
• The protagonist is filled with dread over the thought of a global nuclear war
• One of the characters is a time traveler who reveals that he or she was actually sent back in time to study Aboriginal culture. In the book time travel was an imprecise technology and the character is quite surprised to have arrived while Western civilization is in existence. The character had expected to land somewhere in the 60,000 years of Aboriginal culture rather than the Western post-WWII culture since "your civilization doesn't last very long" (I recall the character saying something to that effect).
• The protagonist or another main character is constantly rolling dice to make decisions.
• The book has at least 2 endings and the canonical ending is chosen by the reader casting a die.

Any help identifying this novel is greatly appreciated!

Answer 1

Beyond the Labyrinth by Gillian Rubinstein

Fourteen-year-old Brenton questions the choices in his life when an alien anthropologist arrives to study an ancient Aboriginal tribe that once lived in the area around his home.

From this review:

At the end of the third last chapter, the narrative suddenly turns to address the reader and asks them to make a choice. Throw the dice and depending on their fall, discover what happens next. Cute and quite effective device to cover the two endings given in the following chapters.

Found with a search for site:goodreads.com australia "time travel" aborigines dice