The Ordovician mass extinction: Our planet’s first brush with death
Cody Cottier writes: Some mass extinctions unfold like a sloppy murder, leaving clear fingerprints for the keen investigator to uncover. (Asteroids are no masters of subtlety.) The Late Ordovician mass extinction, the oldest of all and the second most lethal, isn’t one of them. Though there is a standard explanation for this granddaddy of death — involving an ancient ice age — the evidence is cryptic enough that experts are still submitting new theories for how 85 percent of all…