After analyzing 8,484 kilograms (18,704 pounds) of sedimentary rock from ancient seabeds, scientists have found that major collisions in the asteroid belt have not made any significant contribution to the number of meteorite impacts on Earth, as had been theorized.

"The research community previously believed that meteorite flux to Earth was connected to dramatic events in the asteroid belt," said geologist Birger Schmitz of Lund University in Sweden.

The glaring exception is an increase in this type of meteorite 466 million years ago, associated with the break-up of an L-chondrite parent body, a type of meteorite conspicuously low in iron.

During this time, meteorite flux increased by a factor of up to 300, and 99 percent of the grains were from this one parent body, tailing off after about 40 million years, but never quite ceasing.

"We were very surprised to learn that only one of the 70 largest asteroid collisions that took place over the past 500 million years resulted in an increased flux of meteorites to Earth," Schmitz said.