Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Meteorites rained on Earth after massive asteroid breakup


Geologists find meteorites 100 times more common in wake of ancient asteroid collision

Using fossil meteorites and ancient limestone unearthed throughout southern Sweden, marine geologists at Rice University have discovered that a colossal collision in the asteroid belt some 500 million years ago led to intense meteorite strikes over the Earth’s surface.

The research, which appears in this week’s issue of Science magazine, is based upon an analysis of fossil meteorites and limestone samples from five Swedish quarries located as much as 310 miles (500 km.) apart. The limestone formed from sea bottom sediments during a 2 million-year span about 480 million years ago, sealing the intact meteorites, as well as trace minerals from disintegrated meteorites, in a lithographic time capsule.

"What we are doing is astronomy, but instead of looking up at the stars, we are looking down into the Earth," said lead researcher Birger Schmitz, who conducted his analysis during his tenure as the Wiess Visiting Professor of Earth Science at Rice. Schmitz is professor of marine geology at Göteborg University in Sweden.

Meteorite activity on earth is relatively uniform today, with an average of about one meteorite per year falling every 7,700 square miles (12,500 sq. km.). The new study found a 100-fold increase in meteorite activity during the period when the limestone was forming, a level of activity that was present over the entire 150,000-square-mile (250,000 sq. km.) search area.

Some 20 percent of the meteorites landing on Earth today are remnants of a very large asteroid that planetary scientists refer to as the "L-chondrite parent body." This asteroid broke apart around 500 million years ago in what scientists believe is the largest collision that occurred in late solar system history.

Schmitz and his colleagues looked for unique extraterrestrial forms of the mineral chromite that are found only in meteorites from the L-chondrite breakup. They found that all the intact fossil meteorites in the Swedish limestone came from the breakup. Moreover, they found matching concentrations of silt and sand-sized grains of extraterrestrial chromite in limestone from all five quarries, indicating that meteorite activity following the breakup was occurring at the same rate over the entire area.

The research helps explain why Schmitz and his colleagues at Göteborg have been able to collect so many fossilized meteorites from a single quarry near Kinnekulle, Sweden over the past decade. Fossil meteorites embedded in stratified rock are extremely rare. Only 55 have ever been recovered, and Schmitz’s group found 50 of those.

"It is true that we are lucky to be looking in just the right place -- a layer of lithified sediments that was forming on the sea floor immediately after this massive collision," said Schmitz. "But on the other hand, we would never have started looking there in the first place if the quarry workers hadn’t been finding the meteorites on a regular, yet still rare, basis."

Until Schmitz’s group started working with the quarry crew, the fossilized meteorites were discarded because they blemish the finished limestone. Schmitz believes it’s possible that similar concentrations of fossilized meteorites and extraterrestrial chromite grains are present worldwide in limestone that formed during the period following the asteroid breakup. He recently got funding to look for evidence of this in China, and he said there are South American sites that are also favorable.

The research was sponsored by the National Geographic Society and the Swedish Research Council.

Jade Boyd | EurekAlert!
Further information:

More articles from Earth Sciences:

nachricht UCI and NASA document accelerated glacier melting in West Antarctica
26.10.2016 | University of California - Irvine

nachricht Ice shelf vibrations cause unusual waves in Antarctic atmosphere
25.10.2016 | American Geophysical Union

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>