Analytical chemistry and the extinction of dinosaurs

Measurement science influences other sciences and sometimes from quite an unexpected angle. A recent review on extinction of the dinosaurs (the “Mass Extinction at the Cretaceous-Paleogene Boundary”, to put it in a scientifically correct way) published in the prestigious Science journal (Science 2010, 327, 1214-1218) confirmed that the most likely cause of dinosaur mass extinction was an asteroid impact at around 65.5 million years ago. Consequences of this event included a long dark and cold period, as well as possible acidification of the ocean. This led to dying of most of the plants on the planet (which later largely recovered from seeds and roots) and most of the creatures that feeded on plants or other creatures. Among them almost all dinosaurs.

Interestingly, this hypothesis was originally proposed based on chemical measurement (analytical chemical) data. It was discovered (Science 1980, 208, 1095-1108) that in sediments of roughly this age there was sharply increased iridium content (by up to ca 100 times). This was interpreted as a consequence of an iron meteorite hitting the earth. Iron meteorites are quite rich in platinum metals and the fierce explosion that takes place on the impact distributes the platinum metals inot the atmosphere all over the world, where it thereafter gradually precipitated.

(Image: by NASA, via Wikipedia)

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