Abstract:
Isotopic and temperature measurements from large, cold springs
in the central Oregon Cascades are used to understand where this water
comes from and how old it is. In particular, we employ the isotopes
of helium, carbon, oxygen, and hydrogen to address these issues and
to understand some aspects of the subsurface geology in this region.
we find that large, cold springs in the central Oregon Cascades are recharged
near the Cascades crest up to 50 km from the springs. We also find that the
large springs in the study area discharge water that is a few years old.
Finally, we show that deeply circulating groundwater advectively
transports geothermal heat and magmatic volatiles to several of the springs
such as the Metolius River and Lower Opal Springs.