Paleontology - Experts find no evidence for a mammoth-killer impact

A devastating cosmic collision is the main reason for mammoth-killer impact. Nanodiamonds produce a narrow NMR peak centered chemical shift of parts per million. PNAS spectrum centered at 38 parts per milliom. An iridium 'spike' was first clue identifying the impact that caused the Cretaceous-Tertiary ( K- T) mass extinction. The metallic element is scarce in Earth's crust but relatively abundant in meteorites, so like nanodiamonds, any excess might have arrived via asteroid or comet and caused extinction of animals.