An unexpected discovery in a Namibian desert has led geologists to find traces of ancient ice age movement in plain sight.
A team of geologists travelled to Namibia to study volcanic rocks, but what it took from the trip was something entirely different, and quite familiar to many roamers of the Irish countryside.
The West Virginia University team was travelling through a desert region in the southern African country when it spotted some unusual land formations dotted among the predominantly flat land. The researchers soon realised that these long, steep hills were, in fact, drumlins carved out by glaciers from a time long ago.
“We quickly realised what we were looking at because we both grew up in areas of the world that had been under glaciers, me in Northern Ireland and Sarah in northern Illinois,” said Graham Andrews, an assistant professor of geology.
It was only after Andrews and the rest of his team returned to the US that it became apparent the Namibian drumlins had never been studied.
“The last rocks we were shown on the trip are from a time period when southern Africa was covered by ice,” Andrews said. “People obviously knew that part of the world had been covered in ice at one time, but no one had ever mentioned anything about how the drumlins formed or that they were even there at all.”
While normal glaciers have sequential patterns of growing and melting, they do not move much. However, the team determined that the drumlins featured large grooves, showing that the ice had to be moving at a fast pace to carve the grooves. This is the first evidence of an ice stream located in southern Africa approximately 300m years ago, one that was “really moving fast”, according to Andrews.
These findings, published to Plos One, are also important because they confirm that the region was located over the South Pole during this period, and show yet another tie between southern Africa and South America.