End of an Era Read Online Free PDF Page B

paleontologists who didn’t believe in an impact-extinction correlation outnumbered those who did by four to one. The figure has fluctuated a lot in the intervening two decades, but a show-of-hands at the last SVP meeting indicated support was currently hovering at around twenty percent.
    Really, many paleontologists see two separate issues. One is what caused the interesting geology at the K-T boundary — there’s a clay layer rich in iridium there. The other is what caused the extinctions. The geology may or may not have anything to do with the dyings.
    Klicks believed the asteroid had killed off the dinosaurs; I vehemently disagreed. I wasn’t even convinced that Chicxulub was the source of the iridium layer; like Officer and Drake, I think it’s mostly volcanic in origin. Yes, iridium is rare on the surface of the Earth but plentiful in some kinds of meteors. But Earth does have the same iridium content as most rocky bodies in the solar system; ours is just fractionated into the deep mantle. There’s lots of evidence for volcanism at the end of the Cretaceous. The Deccan Traps in India, for instance, represent at least one million cubic kilometers of basalt that date from the K-T boundary. And volcanic material shows the same concentrations of arsenic and antimony found in the boundary-layer clay, concentrations that are three orders of magnitude greater than what’s normally associated with meteorites.
    Indeed, the largest known impact craters on Earth, including the huge crater remnant off Nova Scotia, show no evidence of iridium deposition. Comets, sometimes named as an alternative culprit, are even less likely: there’s no direct evidence at all for iridium in cometary material.
    Klicks and I had argued these issues many times in person, in print, and once when I was visiting scholar at the Royal Tyrrell Museum in Alberta, where Klicks worked, on a phone-in show on the local community-access cable-TV channel. Klicks had been adamant during that debate: the impact of an asteroid had killed the dinosaurs. It was clear by the calls we got that those members of the public who didn’t have their own crackpot theories almost exclusively sided with Klicks. They wanted to know what all the fuss was about; hadn’t this issue been settled years ago? Everybody knew an asteroid impact had wiped out the dinosaurs.
    Well, we were here.
    And we were going to find out, one way or another.
    I’ve been keeping this diary for years, and tonight, the most exciting of my life, I’m certainly not going to miss making an entry. Someday perhaps I’ll turn these notes into a book about our voyage (editing out the private stuff, of course), so I think I’ll add a little more background detail than usual.
    I typed silently in the dark on my Toshiba palmtop for about an hour, its keyclick shut off and the brightness of its screen turned way down so as not to bother Klicks. When I was done, I swallowed the silver sleeping caplet dry.
    Soon morning would be here. Soon we would step out into the Mesozoic.

Boundary layer
    I never travel without my diary. One should always have something sensational to read in the train.
    —Oscar Wilde, Irish playwright (1854–1900)
    Klicks always took his vacations in Toronto. Partly it was because his parents, both in their seventies, still lived there. Partly it was because his sister and her two sons, whom Klicks doted on, lived just east of the city in Pickering. And partly, I liked to think anyway, it was because he enjoyed spending time with Tess and me — although he did always turn down our invitations to stay at the house, preferring his sister’s luxury condo overlooking Lake Ontario.
    But the main reasons for his frequent trips to the mighty T.O. were the culture and the food, both as good as New York’s. Klicks relished the finer things, and there weren’t a lot of them in Drumheller, Alberta. Tonight we were going to see Andrew Lloyd Webber’s latest musical,
Robinson Crusoe
,