Multiple seismic tomography and waveform inversion studies confirm that remnants of the subducted Farallon plate persist deep within the Earth's mantle, including the lower mantle and near the core-mantle boundary.
The retrieved papers consistently use seismic tomography and waveform inversions to image subducted Farallon plate material in the lower mantle and deep interior, supporting the claim with multiple independent lines of evidence and no dissenting sources.