Dinosaur killer turned earth into desert

The asteroid believed to have led dinosaurs to extinction destroyed all forms of vegetation on earth. Recent finds in New Zealand point to climate disturbances resulting in the destruction of the bulk of trees and blossoming plants. These finds enable us to believe that even the southern hemisphere went through an artificial winter, acid rains, and fierce forest fires. This is the first fossil evidence of the vegetation’s destruction found so far from the Mexican shore where the asteroid crashed.

Dr. Timothy Flannery, an expert at the South-Australian museum in Adelaide says, “The asteroid devastated pretty much everything. This was a case of global devastation rather than North American catastrophe."

About 65 million years ago, 70% of life, including dinosaurs, suddenly disappeared from the fossil record. By piecing together geological and other evidence, scientists are creating a picture of what happened. The idea is that a giant asteroid about 10 kilometers wide and travelling at 90,000 km/hour slammed into the Earth at the southern margin of North America. It probably landed close to what is now the Yucatan peninsula, an area that was then a shallow tropical sea.

The damage to North America is unequivocal. According to fossil deposits, the gulf coast was emptied of life. On land, forests were flattened, fires raged, and four out of five plant species went extinct.

What happened later is harder to establish. There has been very little clear fossil data from places like Australia and Antarctica. Now, geologists at the Lund University, Sweden, and the Institute of Geological and Nuclear Sciences, a research company owned by the New Zealand Government, have reported on new fossil evidence in the journal Science.

It was found on the South Island of New Zealand, which is situated about 11,000 km (almost 7,000 miles) from Mexico. Ancient layers of rock from the Moody Creek mine on the west coast reveal a characteristic accumulation of fern spores and pollen just after the impact is thought to have occurred. It appears that what was once a swamp forest rich in trees and flowering plants was reduced to little more than a bed of ferns.

The mighty eruption of the Krakatoa volcano in 1883 had a similar effect on plants. Bare soil was gradually colonized by only the most hardy of plant species, the fern. This suggests the impact near Mexico triggered global changes across most of the planet. Dust would have been blasted into the atmosphere, cutting off sunlight and triggering a spell of dramatic cooling.

There would have been freezing temperatures on the ground and too little light to support photosynthesis. The end result, it seems, is that many land plants were destroyed. Scientists are searching for similar fossil evidence on other southern continents that could add to the growing picture of how the dinosaurs died out.

Read the original in Russian: http://www.km.ru/magazin/view.ap?id=14AB46614C28494DA75F411EBC3E7D03

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