Why is there salt in the great salt lake?

I'm doing a school project and i need to know why there is salt in the great salt lake.Why is there salt in the great salt lake?
because there is no outlet river.
It is thought that The Great Salk Lake is what is left of an OCEAN that once covered that part of the world. The ocean receded and pulled back, leaving the Great Salk Lake as its remnant.



it is ALSO thought that the spires and buttes in Monument Valley National Park used to be ISLANDS in that ocean!Why is there salt in the great salt lake?
eons ago the ocean there dried up and all the salt in the ocean remains in the great salt lake
Because they haven't got it all out yet.