We think we are looking at the remains of some very old seawater trapped during the Miocene period, some 5 million years ago, he said.

Lyons and his colleagues believe that as the glacier moved forward down through the valley, it captured some of the deposit and forced it up into the body of ice. Eventually, the deposit reached the margin, or edge, of the glacier and is being slowly pushed out or the ice.

As the reddish, icy sludge melts at the margin of the glacier, it runs off into Lake Bonney, one of only four ice-covered lakes in the Dry Valleys. Three of the lakes Bonney, Fryxell and Hoare are in Taylor Valley while Lake Vanda is in the nearby Wright Valley. But each of these lakes is very different chemically and the explanation for those differences has puzzled researchers for years.

The water at the bottom of Lake Bonney, the most landward of the Taylor Valley three, is saturated with salts, Lyons said. But Lake Hoare a short distance down the valley from Bonney is filled with fresh water. Lake Fryxell is also a saltwater lake.

Scientists have wondered for years how three lakes so close together, with the same climate regime and the same geology, can be so different chemically, Lyons said. We think it has to do with the ages of these lakes.

"The research team believes that orginally water drained down the valley to Lake Fryxell. But at some point in the past as temperatures warmed, the Canada Glacier flowed further into Taylor Valley and blocked this flow. Lake Hoare was then formed on the lower side of the Canada Glacier and filled with fresh water from glacial runoff.

Lake Hoare basically forms only during the warm times when the Canada Glacier advances down into the valley.

Aside from the oddity of Blood Falls itself, a better understanding of how these lakes formed and exactly when should enhance
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Contact: Berry Lyons
Lyons.142@osu.edu
614-688-3241
Ohio State University
4-Nov-2003