What is Man? by Edgar Andrews

Author:Edgar Andrews
Language: eng
Format: epub
Tags: Non-Fiction/Nature/Environmental Conservation & Protection
Publisher: Elm Hill
Published: 2018-03-01T16:00:00+00:00

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Perhaps dating your discovery will clarify the muddy anthropological waters? So you submit a bone to a Carbon 14 (abbreviated 14C) dating lab, the soil and stones to geological experts, and the volcanic rock sample for radiometric dating. The results eventually come through. The 14C measurement is inconclusive. It gives an age of around 3000 years (recent by PA standards) but the bone is porous and the lab suspects that live bacteria may have contaminated the specimen with their own 14C. The bone could be almost any age. The radiometric dating of the volcanic rock puts its age at two million years or so, but the experts point out that this rock may have no age-related connection with the fossil you found. If a fossil lies below a stratum of igneous rock, it is reasonable to assume that it is older than the rock in question, but this neat arrangement doesn’t apply to your skeleton. Even if it did, radiometric dating doesn’t necessarily give correct ages for rock, as we shall see presently.

What about the soil and stones? They can’t date the skeleton radiometrically, because they are erosion products from more ancient rocks—which could predate the creature by any amount of time. But there is one interesting piece of news—among the stones are “index” fossils that are typically found in rock strata from the “Pleistocene period” which (according to the accepted geological timescale) lasted from 2.58 million to 11,700 years ago. Could this mean that Fred is of similar age? Perhaps, but perhaps not. The index fossils occur in water-worn pebbles, and even if the pebbles were deposited during Fred’s lifetime, they could have derived from much older virgin rock. They put an upper limit on Fred’s geological age but leave the lower limit undefined.

Finally, what seems to be an ancient sharpened flint “knife” is found among the stones. Could this suggest that Fred used tools to skin and cut up food? Or might it indicate that humans hunted Fred and his tribe for their lunch? No one knows the answer. Also, the “knife” might just be a broken flint that just happens to resemble a crude tool. Or, like the pebbles, it could be much older than Fred. Or again, it might have been transported from a more recent location the last time the cliff suffered a rock fall.

However, you have faith in Fred and decide to opt for the radiometric rock-sample date, even though the rock measured was some distance from his final resting place. Armed with this tentative age, you find a copy of the latest evolutionary family tree for hominids and consider where in that tree you should put Fred. Do you succeed? You’ll find out at the end of the chapter.

BEGINNER’S LUCK

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