Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Meteorites rained on Earth after massive asteroid breakup

09.05.2003


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:
http://chico.rice.edu/

More articles from Earth Sciences:

nachricht A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington

nachricht Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>