Time Pebbles - Jerry Merritt

Tekla, son of an ancient shaman, loses Ka Li when she is torn from his life by a brutal tribe of Denisovans in a Late Pleistocene kidnapping.
Ka Li escapes but is unarmed and forced to flee across the Bering land bridge where she becomes hopelessly lost in the endless tracts of North America. Only Tekla cares enough to search for her over the years. As Ka Li survives fierce predators and scarce resources she leaves behind a series of signal cairns to help Tekla find her.
Skipping forward 60,000 years, Helen Ryland, a mid-twentieth century archaeologist, unearths one of Ka Li's surviving signal cairns and realizes she has found trace of people who populated the Americas even before the Clovis culture. Helen's detective work tracking Ka Li's timeless signals across the Alaskan wilderness now intertwines with Ka Li's story. As Helen solves the puzzle of the signal cairns she finds universal fame and suffers devastating misfortune. In the end Helen discovers that science in isolation cannot answer all of her questions for Tekla's devotion to Ka Li had not died even though six hundred centuries had passed.