Again ... not sure why this is 'news' ... from Discovery.com:

Remains of rotten fish entrails have helped establish the precise dating of Pompeii's destruction, according to Italian researchers who have analyzed the town's last batch of garum, a pungent, fish-based seasoning.

Frozen in time by the catastrophic eruption that covered Pompeii and nearby towns nearly 2,000 years ago with nine to 20 feet of hot ash and pumice, the desiccated remains were found at the bottom of seven jars.

The find revealed that the last Pompeian garum was made entirely with bogues (known as boops boops), a Mediterranean fish species that abounded in the area in the summer months of July and early August.

"Analysis of their contents basically confirmed that Mount Vesuvius most likely erupted on 24 August 79 A.D., as reported by the Roman historian Pliny the Younger in his account on the eruption," Annamaria Ciarallo, director of Pompeii's Applied Research Laboratory told Discovery News.

The vessels were unearthed several years ago in the house of Aulus Umbricius Scaurus, Pompeii's most famous garum producer.

So ... what you're suggesting is we now have an ancient dating technique which is accurate to the day? Riiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiight .... I suspect the real news was identifying the fish involved and they (the journalists?) didn't think that was newsy enough ...