Explain the unusual observations Walter Alvarez made in the Scalgia rossa formation in Umbria.
The correct answer and explanation is :
Walter Alvarez made an unusual observation in the Scaglia Rossa Formation in Umbria, Italy, which significantly contributed to the understanding of the extinction event that occurred at the end of the Cretaceous period. The Scaglia Rossa Formation is a layer of rock that dates back to around 66 million years ago, the time of the mass extinction event that wiped out the dinosaurs.
Alvarez and his team discovered an unusually high concentration of iridium in a thin layer of rock within the Scaglia Rossa Formation. Iridium is a rare metal that is typically found in asteroids or comets, not in significant amounts on Earth’s surface. The unusually high levels of iridium suggested that a cosmic object, such as an asteroid or comet, had collided with Earth, depositing iridium at the impact site.
This discovery was groundbreaking because, at the time, there was no widely accepted explanation for the mass extinction event at the end of the Cretaceous. While many scientists had proposed theories such as volcanic activity, climate changes, or diseases, the presence of iridium in the Scaglia Rossa Formation provided compelling evidence for the hypothesis that a massive asteroid impact had played a crucial role in the extinction event. The iridium layer, known as the “Cretaceous-Paleogene (K-Pg) boundary,” was later found at many other locations around the world, further supporting this impact hypothesis.
The Alvarez hypothesis led to further research on the Chicxulub crater in Mexico, which was identified as the site of the impact. The discovery of the iridium layer in the Scaglia Rossa Formation played a pivotal role in the development of the impact hypothesis, forever changing our understanding of the mass extinction event and its link to the end of the age of dinosaurs.