Sea-floor sediment core, on deck. Photo © NOAA Pacific Marine Environmental Laboratory

My grandmother died 23 years ago this week, just shy of her 100th birthday. During her life, she pioneered a homestead with her father and brothers, farmed large tracts of land with her husband, built two family homes, raised 12 kids, and fed her umpteen grandchildren countless farm-fresh meals of traditional French cuisine.

The broad brushstrokes of her life that I know are supplemented by a few stories and a handful of photographs.

When I visited her in her final weeks, I marveled at the map of her life that was her face. If only there was a way to read a person’s history in crow’s feet, wrinkles, wattles and jowls.

One can do that, to a limited extent, by scanning their bones and chemically analyzing their hair, but both of these records of a person’s diet, activity, health and environment extend only a short time into the past. Hair grows at a rate of about one centimetre each month, and is cut regularly. Few people tolerate the hassle of Rapunzel-like dos these days. Bone, too, regenerates constantly, with new cells replacing old. Researchers estimate the bone in humans is gradually replaced every seven or so years. More »