Shop Windows to the Universe

With Explore the Planets, investigate the planets, their moons, and understand the processes that shape them. By G. Jeffrey Taylor, Ph.D. See our DVD collection.
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."

Last modified June 11, 2009 by Jennifer Bergman.

Shop Windows to the Universe Science Store!

Our online store includes books on science education, ranging from evolution, classroom research, and the need for science and math literacy!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Kingdom Plantae

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

What Is a Fossil?

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

Triggers of Volcanic Eruptions in Oregon's Mount Hood Investigated

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

Oldest Earth Mantle Reservoir Discovered

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

Its Not Your Fault A Typical Fault, Geologically Speaking, That Is

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

Lower Solar Activity Linked to Changes in Sun's Conveyor Belt

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

Growth Spurt in Tree Rings Prompts Questions About Climate Change

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

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA