Scientist Sophie Newbury studies the "dead zone," a rock layer in Karoo Basin.
Courtesy of Robert Gastaldo, Colby College
Geologic Findings Undermine Theories of Permian Mass Extinction Timing
News story originally written on March 2, 2009
Tens of millions of years before dinosaurs roamed Earth, their ancestors were all but eliminated in a catastrophic event called the Permian
Mass Extinction. This was the greatest extinction event ever in Earth's history! The Permian period extended from 299 to 252.6 million years ago.
Geologists have made some discoveries that call into question popular theories about this Extinction.
Before, scientists thought they had found a distinct record of the Permian Mass Extinction in sedimentary rocks found across southern hemisphere continents. There was actually a layer in the rocks that scientists called the "dead zone" because of the lack of plant and animal fossils found there.
But recent work done in the Karoo Basin in central South Africa, where the best fossils records from the Permian time period are found, shows conflicting evidence in the layers of rock found.
They discovered that this dead zone layer is not found at the same physical position in the rock record at all places, even across a land area 1 kilometer across. As such, it is not a reliable marker of the mass extinction of terrestrial animals.
Lead geologist on this project, Robert Gastaldo, says that the research proves that "there is no evidence to support a terminal extinction event in the record of the Karoo Basin, based on the criterion of an unique event bed or dead zone."
Shop Windows to the Universe Science Store!
Our online store
includes issues of NESTA's quarterly journal, The Earth Scientist
, full of classroom activities on different topics in Earth and space science, ranging from seismology
, rocks and minerals
, and Earth system science
You might also be interested in:
Kingdom Plantae contains almost 300,000 different species of plants. It is not the largest kingdom, but it is a very important one! In the process known as "photosynthesis", plants use the energy of the...more
Fossils are evidence of ancient life preserved in sedimentary rocks. On Earth, they are clues to what living things, ecosystems, and environments were like in the past. The oldest fossils are from mats...more
Scientists have learned that Mount Hood, Oregon's tallest mountain, has erupted in the past due to the mixing of two different types of magma. "The data will help give us a better road map to what a future...more
The Earth's mantle is a rocky, solid shell that is between the Earth's crust and the outer core, and makes up about 84 percent of the Earth's volume. The mantle is made up of many distinct portions or...more
Some geologic faults that appear strong and stable, slip and slide like weak faults, causing earthquakes. Scientists have been looking at one of these faults in a new way to figure out why. In theory,...more
The sun goes through cycles that last approximately 11 years. These solar cycle include phases with more magnetic activity, sunspots, and solar flares. They also include phases with less activity. The...more
Studying tree rings doesn't only tell us the age of that tree. Tree rings also show what climate was like for each year of a tree's life, which means they can tell us about climates of the past and about...more