Glen Penfield
The oil company geophysicist who found a giant buried ring under Mexico's Yucatán Peninsula in 1978, later shown to be the Chicxulub crater.
Key facts
- Nationality
- American
- Field
- Geophysicist
Glen Penfield was a geophysicist working for the Mexican state oil company, Pemex, in the 1970s. In 1978 he was flying an airborne survey that measured tiny changes in the Earth's magnetic field over the Gulf of Mexico and the Yucatán Peninsula, looking for rock structures that might hold oil.
On the maps he noticed a huge, curving pattern centred near the coastal town of Chicxulub. When he compared it with earlier gravity maps of the land, made by Pemex geologists, he and his colleague Antonio Camargo saw that the curve was part of a giant ring, roughly 180 kilometres across, buried under hundreds of metres of younger limestone. They suspected it was an impact crater.
In 1981 they presented the idea at a geophysics meeting, but it drew little attention, and Pemex rules limited what they could publish. A decade later Alan Hildebrand, who was searching for the crater linked to the extinction of the dinosaurs, learned of their work. Together they published the evidence in 1991, including shocked quartz from old drill samples.
Penfield's discovery is a reminder that great finds can come from careful work done for quite different reasons.