David Hilton, Ph.D.
scripps institution of oceanography
)
A serendipitous result of the Andes work was the finding that high 3He/4He
ratios were not only characteristic of regions of extensional tectonics
(e.g. areas of rifting, divergent plate boundaries) but those of compression
as well (in this case the Puna region of Argentina).
This finding was interpreted in terms of melt intrusion related to 'continental delamination'.
This work was followed up with an extensive helium isotope survey of the
Altiplano region of the Andes where the melt additions were mapped over
a huge region.
)
Continuing research on hydrothermal fluids from the Tibetan
Plateau have found high 3He/4He ratios in the thickest crust on Earth
- a totally unexpected result - confirming the utility of helium isotopes
to recognize and distinguish continental delamination processes from other
models of high plateau formation.