From the Field: Digging for Fossils in Churchill’s Trenches

Posted: August 31, 2011 - 08:57 , by royal

July 22

Another ominously grey and chilly day dawns, but thankfully the rain holds off and after a fortifying breakfast we trundle down to the coast to warm up with some – whoopee – trench digging! It isn’t just any ordinary trench, however … this excavation will allow grad student Matt Demski to collect through a 1.5 metre-thick section that includes the boundary between Upper Ordovician and Lower Silurian strata, representing an interval of time that encompasses one of the greatest mass extinctions known in the fossil record. After getting things underway, three of us move a few kilometres east along the shore, leaving Matt to measure and collect samples for critical isotope analysis, while Ed stands polar bear watch.
Diggin for fossils in the stony trenches outside Churchill.

Matt and Graham dig, Ed does his GPS magic, and Debbie records the activity at our new Ordovician-Silurian boundary section. Careful study of geochemical signatures and microfossils from these rocks can tell us a lot about the nature of the extinction event in this part of the Paleozoic world.

Researchers sort through the rocky in search of fossils.

A little way down the coast, Graham and Debbie patiently search for subtle signs of soft-bodied fossils at our main fossil locality … like looking for invisible needles in an Upper Ordovician haystack!

Late in the day, with the first lot of trench samples secured and a few promising soft-bodied fossils wrapped and bagged, we head back to the Studies Centre to regroup. Tonight, after dinner, we decide to take advantage of the low tide to check another remote bit of Hudson Bay shoreline where older reports suggested the presence of Upper Ordovician or Lower Silurian fossil-bearing rocks. No rain, but the dense fog requires us to be on high alert for the presence of other large mammals on the tidal flats.

Almost hidden in the fog, researchers look for fossils along the shore when the tide is out.

Out on the tidal flats Debbie, Matt, and Graham search for traces of fossiliferous outcrop around an ancient island of Precambrian quartzite, while I keep watch from the highest vantage point.

Heavy fog hangs of the Churchill landscape.

The grounded hulk of the MV Ithica looms out of the evening fog.

The sun sets over the tidal flats.

Time to head for home.

 No sign of the elusive Ordovician outcrops, so with failing light and deepening fog we check our bearings and cautiously return to the vehicle. There are notes to write up, pictures to download, and plans to be made before calling it a day.