Nova Scotia town’s sinkhole eats into Lions’ parking lot
OXFORD, N.S. — A large sinkhole that has swallowed trees and picnic tables in a Nova Scotia park has now taken a bite out of a parking lot as the natural phenomenon continues to capture the attention of geological experts and curious onlookers alike.
The Town of Oxford said Friday the unpredictable sinkhole had remained relatively inactive Thursday.
But it said the muddy hole has been “undercutting” the pavement of the nearby Lions Club parking lot, and pieces of pavement are now falling in.
Amy Tizzard, a geologist with the Nova Scotia Department of Energy and Mines, said the sinkhole was 37 metres by 29.8 metres on Friday, up from 34 metres by 29 metres on Tuesday. She said the sinkhole’s growth has slowed.
“However, it’s still unpredictable,” said Tizzard. “So we’ll continue to monitor the area.”
Tizzard has said the likeliest cause is an underground cavern caving in the soft gypsum rock that’s common in the region.
Todd Ventura, a professor in the geology department at Saint Mary’s University in Halifax, said sinkholes usually form over limestone and it’s less common to have a sinkhole formed from gypsum, which is an evaporite — a mineral resulting from the evaporation of water.
“We’re quite intrigued by this, because these are much more rare events,” Ventura said. “It’s going to be really interesting to see what happens here. How much more it will grow? Are there others around?”
Ventura said gypsum is not hard, like limestone, and behaves almost like a wax under pressure.
“It can move. And so as you’re dissolving the gypsum, instead of the gypsum then creating typically a cave, it just sort of creates a slump,” said Ventura, a geochemist.
Venutra said sinkholes happen when the roof of an underground cave becomes so unstable it essentially collapses. All the rock, soil and sediment above will also collapse and fall down to fill the void below, he said.
He added that there’s not much one can do to stop a sinkhole from growing: “This is nature.”