From time to time, Earth’s magnetic field flips, turning north to south. Magnetic minerals in the soil and ocean are pushed into alignment with the field; when they are trapped in rocks, they still point in the telltale direction.
Geophysicists have precisely determined the timing of these magnetic flips, which have taken place at the same time all around the world. It’s a useful way to date the material found in layers of rock.”
Always seemed like one fantastical theory being supported by another fantastical theory. (Don't worry, I'm not a tectonic skeptic.)
It's even shown on a BBC documentary, they get disappointed when DNA analysis disproves their skull-shape "evidence".
https://en.wikipedia.org/wiki/The_Incredible_Human_Journey#2...
With significant and predictable sadness when the results didn't go their (the CCP and Chinese nationalists) way.
A google search gives a good paper on the topic:
https://core.ac.uk/download/pdf/28941533.pdf
TLDR: CCP, seeking to shore up ethno-nationalism (not an especially rare occurance in Chinese history) spent a LOT of time and research trying to prove that Han Chinese are in fact originally descended from Homo erectus Pekinensis rather than the African Homo Sapiens. (EDIT: Spelling)
Also, reminded of the endless jokes about who is more advanced from what archeologists find in their own country: Americans find copper wire: invented primitive networks. Russians find Glass threads: invented optical networks. Irish dig up a bog and find nothing: invented wifi!
Go back 2.1 million years, like these stone tools, and it's not even clear that there is a genus Homo.
But that reflects improvements in technology, not anything about what’s being measured.