Related Experiment Video
Updated: Jul 8, 2026

Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System
Published on: June 5, 2014
Mineralogic evidence for an impact event at the cretaceous-tertiary boundary
Abstract:
A thin claystone layer found in nonmarine rocks at the palynological Cretaceous-Tertiary boundary in eastern Montana contains an anomalously high value of iridium. The nonclay fraction is mostly quartz with minor feldspar, and some of these grains display planar features. These planar features are related to specific crystallographic directions in the quartz lattice. The shocked quartz grains also exhibit asterism and have lowered refractive indices. All these mineralogical features are characteristic of shock metamorphism and are compelling evidence that the shocked grains are the product of a high velocity impact between a large extraterrestrial body and the earth. The shocked minerals represent silicic target material injected into the stratosphere by the impact of the projectile.
Related Concept Videos
The Fossil Record
Impulse
Additionally, it can be shown that the total...
Types Of Collisions - I
Types of Collisions - II
Elastic Collisions: Case Study
Impact
When particles with different initial velocities collide, they induce deformation by applying equal and opposite impulses. At the point of maximum deformation, the particles move together with...

