Geology grad student studies groundwater discharge from sinkhole in Great Lakes

Tom Novell, a Wayne State University graduate student working on his Geology Masters Degree research project under the direction of Dr. Mark Baskaran, is investigating the characteristics of groundwater discharging from a sinkhole on the bottom of Lake Huron.

Tom is using several different sampling and analytical methods to determine the age of the sinkhole waters and to identify their sources. An important part of his work is to collect and analyze groundwater samples for radium, chlorine, oxygen and hydrogen isotopes. Radioactive chlorine isotopes, for example, can be used to date the groundwater.

The radioactive isotopes are initially created by cosmic radiation from the sun and incorporated into surface waters. As surface water infiltrates into the subsurface to become groundwater, the initial radioactive chlorine concentration decays at a constant rate over time, thus providing a means to estimate the time that the water has spent underground, away from the influence of cosmic rays.