This would be the smaller sibling to U8b>K which seems to have survived among the Anatolian & Caucasian Hunter Gatherers, and would then expand back into Europe with the introduction of agriculture.
U8a is the most divergent mtDNA lineage a European can belong it. It diverged from all other U8 lineages about 37,000 years ago. It was very common in the Magdalenian culture then became very rare after they were mostly replaced by WHG. Modern people with it all descend from a common ancestor, most likely from the Solutrean culture, who lived 20,000 years ago.