They may have contributed to the mass extinction that ended the reign of the dinosaurs. Plants convert carbon dioxide into oxygen during photosynthesis, the process they use to make their own food.
He and his son, noted geologist Walter Alvarez, were conducting research in Italy when they discovered a centimeter-thick layer of iridium-enriched clay at the K-T boundary. A scientist who works in that field is known as a physicist. The mineral crystals that make up rock are usually too small to be seen with the unaided eye.
Researchers found that Cretaceous sites, prior to the extinction event, had rich plant and insect-feeding diversity.
This means that the eruptions were raging at the height of the extinctions. Erosion has uncovered dinosaur bones. Diversification of mammals stalled across the boundary.
It incorporates scientists from many different fields including astrophysics, astronomy, geology, paleontology, ecology, geochemistry, and so on. Studies of fossils found or not found across the boundary between these two periods — abbreviated the K-Pg boundary — show that some three out of every four plant and animal species went extinct at about the same time.