"And this opens a new field for the study of nuclear synthetic anomalies"-Ke Zhu

This LPI is using the relative abundances of Chromium to infer some details about what kinds of minerals were abundant in the very early solar system proto-planets. Ureilite and Aubrite meteors are often speculated to be of Mercury origin, or otherwise a protoplanet that has since been destroyed and the majority of its debris consumed in other planetary bodies. Chromium isotope dating is great for us because 3.7 million years is a pretty modest margin by astrogeology standards. 

• At 10:00 a nice overview of early chondrites
• At 15:00 he goes into the chondrules components. Some of the eldest bits known.
• At 23:30 he starts going over rocky worlds, Earth, Vesta, and Mars.
• At 46:20 he touches on the origins of Phobos and Demos as ejecta, which is widely accepted though still a bit of a secret. Chromium dating supports. 

I really like isotopic dating but I have to confess relative abundances of isotopes puts me straight to sleep. This lecture took me a minute to get though, but the good side is that it really was a thorough disclosure for those who better my attention span. It's perfect for those with aptitude for this kind of chemistry. The relevance of course is fundamental. Employment for isotopic dating is now and will continue to be in high demand.