Through their research study of seismic anisotropy in the upper section of the lower mantle underneath the Philippine Sea Plate, they found that the ancient lower mantle flow field is still preserved there.The study was released in Nature Geoscience.The lower mantle is a crucial layer of the Earth and may play a crucial function in the evolution and product biking of Earths interior. They are also independent of a mantle plume, as there has been no active mantle plume underneath the PSP considering that the early Cenozoic.Based on previous seismological results and geodynamic simulations, the researchers inferred that the N-S FVDs at depths of 700– 900 km show the residue Pacific lower mantle flow field at about 50 Ma.In addition, the 2 separated quickly speed abnormalities are consistent with seismic scatterers at depths of 1,000– 1,800 km identified by previous seismological research studies, and their places are usually constant with that of the dispersing center in between the Izanagi and Pacific plates when this dispersing center was about to subduct underneath the Eurasian Plate. Credit: IOCAS”The NW-SE FVDs in the 2 separated fast anomalies are further inferred to reflect the Pacific lower mantle circulation field at about 40 Ma, due to the fact that the two isolated fast speed abnormalities are surrounded by amorphous mantle flow field and are not impacted by the present lower mantle circulation,” said Prof. Fan Jianke from the Institute of Oceanology of the Chinese Academy of Sciences (IOCAS), corresponding and very first author of the study.