Friday Headlines, September 28, 2018
THE LATEST IN THE GEOSCIENCES
This week in geology
- “Mysterious” collapsing bridge
This week in the environment
- Tree ring lab
It was really no great mystery. Within six hours of opening, a bridge in Canada collapsed into the river it was meant to span. The support pilings in the river sank into the sediments, taking the bridge with it.
But why? It turns out that the company building the bridge felt that a geotechnical study of the ground where the bridge was to be built was too expensive (and according to them, one can’t drill underwater anyway). Besides, this bridge might only be crossed by 1000 cars a year.
Just to make it clear, I’m pretty sure that rebuilding the bridge will cost more than the geotechnical study would have. Also, you can totally drill underwater.
The study of tree rings is called dendrochronology, and is one of many ways to get exact dates of events from the past – even before the advent of human civilization. Each ring in a tree represents a single growing season, usually one year. The width and overall shape of that ring provides information about water availability, growth, and environmental crises that may have taken place during that year. The pattern is the same for all trees in a region, and through matching of patterns, environmental events may be traced back for thousands of years!