Not widely known I think - here is a neat write up on it [https://repository.geologyscience.ru/bitstream/handle/123456789/37061/Mann_04.pdf?sequence=1 https://r

Not widely known I think - here is a neat write up on it [https://repository.geologyscience.ru/bitstream/handle/123456789/37061/Mann_04.pdf?sequence=1 https://repository.geologyscience.ru/bitstream/handle/123456...] And another [https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2002GC000392 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...]