Dr. Ryan Ewing, professor in the Department of Geology and Geophysics at Texas A&M. (Ryan Ewing/Texas A&M University College of Geosciences)
Those layers of sedimentation provided a time-scale for the team’s analysis, showing that the calculated water depths of 9-16 meters remained nearly constant for about 100 years, throughout 27 meters of sediment accumulation.
“To accommodate that much sediment accumulating over a short amount of time — about 27 meters of sediment accumulation over 100 years — that requires a rate of sea-level rise of about one foot per year,” he said.
The team’s proof of “extraordinarily rapid rate of sea-level rise,” as their publication states, validates a major tenant of the Snowball Earth hypothesis: that rapid deglaciation occurred during the early transition to a super-greenhouse climate.
“It’s really the fastest rate of sea level rise that’s ever been estimated on Earth,” Ewing said. “For reference, it’s 100-times greater than current-day rates, and 5-times greater than the fastest sea-level rise following the recent Pleistocene glaciations.”
The rocks analyzed in this study, those deposited following the Marinoan glaciation, are found in only a handful of locations around the planet, including the formation in South Australia.
“One of the interesting things about the Snowball Earth hypothesis is that you can find these rocks on every continent except Antarctica, which is why it is thought to be a global glaciation,” he said. “The rocks we studied in Australia are also unique because they were deposited near the equator 635 million years ago and support evidence of glaciation at the equator. This is rare, and again makes the Snowball Earth hypothesis a realistic scenario for this time period.”
Media contact: Leslie Lee, College of Geosciences, (979) 845-0910, firstname.lastname@example.org.