[Rockhounds] A steeply-inclined trajectory for the Chicxulub impact

[Kreigh Tomaszewski]

The environmental severity of large impacts on Earth is influenced by their
impact trajectory. Impact direction and angle to the target plane affect
the volume and depth of origin of vaporized target, as well as the
trajectories of ejected material. The asteroid impact that formed the 66 Ma
Chicxulub crater had a profound and catastrophic effect on Earth’s
environment, but the impact trajectory is debated. Here we show that impact
angle and direction can be diagnosed by asymmetries in the subsurface
structure of the Chicxulub crater. Comparison of 3D numerical simulations
of Chicxulub-scale impacts with geophysical observations suggests that the
Chicxulub crater was formed by a steeply-inclined (45–60° to horizontal)
impact from the northeast; several lines of evidence rule out a low angle
(<30°) impact. A steeply-inclined impact produces a nearly symmetric
distribution of ejected rock and releases more climate-changing gases per
impactor mass than either a very shallow or near-vertical impact.

https://www.nature.com/articles/s41467-020-15269-x