How dust cloud shaped life on earth?Date: 19 September 2019 Tags: Miscellaneous
Scientists have said that dust spawned by a gigantic collision in the asteroid belt between Mars and Jupiter 400 million years earlier triggered an ice age on Earth and subsequently shaped life in Marine ecosystem.
The event occurred when life was concentrated in the seas and far before vertebrates first walked on land. This set in motion evolutionary changes in invertebrates fundamental to marine ecosystems that allowed them to adapt to global cooling.
The inner solar system was filled with enormous amounts of dust after an asteroid more than 150 km in diameter was struck by a smaller object perhaps 20 km wide.
Solar radiation reaching Earth's surface was reduced for at least 2 million years by the dust in space and in the planet's atmosphere.
Another cooling mechanism that occured was that the iron-rich meteoritic dust fertilized large parts of the ocean surface leading to increased plankton productivity and fixing of atmospheric carbon dioxide.
The researchers also found traces of dust in sedimentary rocks formed at the time containing special helium isotopes and rare minerals that revealed its extraterrestrial origin.
The cooling event took palce slowly and thus enabled marine life during the Ordovician Period to adapt.
Earth's climate changed from being tropical to semitropical worldwide to becoming divided into climate zones as it is today with frozen poles and tropical conditions at the equator.