DI­NOSAUR-KILLING AS­TER­OID IM­PACT WAS WORSE THAN WE THOUGHT

BBC Earth (Asia) - - Update | The Latest Intelligence -

Some 66 mil­lion years ago, an as­ter­oid struck the Yu­catan penin­sula in Cen­tral Amer­ica, form­ing the Chicx­u­lub crater and wip­ing out the di­nosaurs in what is known as the Cre­ta­ceous–Pa­le­o­gene (K–Pg) ex­tinc­tion event. But two new pieces of re­search sug­gest that this im­pact was even more cat­a­clysmic than was pre­vi­ously be­lieved.

A new study pub­lished in the jour­nal Geo­phys­i­cal Re­search Let­ters shows that up to three times as much sul­phur may have been re­leased into the at­mos­phere as a re­sult of the im­pact than pre­vi­ous mod­els have sug­gested. This would have led to a longer pe­riod of global cool­ing, which helps to ex­plain the dev­as­tat­ing ef­fects on the Earth’s fauna at the time.

“Many cli­mate mod­els can’t cur­rently cap­ture all of the con­se­quences of the Chicx­u­lub im­pact, due to uncer­tainty in how much gas was ini­tially re­leased,” said the pa­per’s lead au­thor Joanna Mor­gan, a geo­physi­cist at Im­pe­rial Col­lege London. “We wanted to re­visit this sig­nif­i­cant event and re­fine our col­li­sion model to bet­ter cap­ture its im­me­di­ate ef­fects on the at­mos­phere.”

But per­haps more sur­pris­ing are the re­sults of a study con­ducted at Ja­pan’s Me­te­o­ro­log­i­cal In­sti­tute and To­hoku Univer­sity. In a pa­per just pub­lished in the jour­nal Na­ture, re­searchers Ku­nio Kaiho and Naga Oshima show that the high lev­els of soot and sul­phurous gas that caused the mass ex­tinc­tion were a re­sult of the rocks on the penin­sula be­ing par­tic­u­larly rich in hy­dro­car­bons. Such rocks cov­ered only around 13 per cent of the world’s sur­face, and had the im­pact oc­curred in a dif­fer­ent area where the rocks were less rich in hy­dro­car­bons, the di­nosaurs would most likely have sur­vived.

In other words, the chances of the as­ter­oid im­pact killing off the di­nosaurs as it did were only slightly more than one in 10. Un­lucky…

If the Chicx­u­lub me­teor had shifted tra­jec­tory slightly, di­nosaurs couldstill be roam­ing the Earth to­day

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