Vol­ca­noes, as­ter­oid wiped out di­nosaurs: study

The China Post - - LIFE -

A mas­sive as­ter­oid strike 66 mil­lion years ago trig­gered a string of po­tent vol­canic erup­tions that spelled doom for the di­nosaurs, U.S. re­searchers said Thurs­day.

Just what led to the demise of the di­nosaurs is of­ten de­bated among sci­en­tists, and the latest find­ings in the jour­nal Science sug­gest that both events are to blame, not one or the other.

Sci­en­tists stud­ied the Dec­can Traps lava flows in In­dia, and their most ac­cu­rate dat­ing yet shows that the vol­ca­noes dou­bled their out­put in close prox­im­ity to the as­ter­oid or comet strike that set off the last mass ex­tinc­tion on Earth.

“Based on our dat­ing of the lavas, we can be pretty cer­tain that the vol­can­ism and the im­pact oc­curred within 50,000 years of the ex­tinc­tion, so it be­comes some­what ar­ti­fi­cial to dis­tin­guish be­tween them as killing mech­a­nisms: both phe­nom­ena were clearly at work at the same time,” said lead re­searcher Paul Renne, a Univer­sity of Cal­i­for­nia, Berke­ley pro­fes­sor of earth and plan­e­tary science.

“It is go­ing to be ba­si­cally im­pos­si­ble to as­cribe ac­tual at­mo­spheric ef­fects to one or the other. They both hap­pened at the same time.”

To­gether, the as­ter­oid im­pact and the vol­canic erup­tions would have “blan­keted the planet with dust and nox­ious fumes, dras­ti­cally chang­ing the cli­mate and send­ing many species to an early grave,” said a state­ment from UC Berke­ley.

The im­pact of the as­ter­oid changed the un­der­ground plumb­ing in the vol­ca­noes, mak­ing some magma cham­bers larger so they spouted more lava when they erupted.

It would take Earth and its land and ocean life about 500,000 years to emerge from the dev­as­ta­tion.

“If our high- pre­ci­sion dates con­tinue to pin these three events — the im­pact, the ex­tinc­tion and the ma­jor pulse of vol­can­ism — closer and closer to­gether, peo­ple are go­ing to have to ac­cept the like­li­hood of a con­nec­tion among them,” said co-au­thor Mark Richards, also a UC Berke­ley pro­fes­sor of earth and plan­e­tary science.

“The sce­nario we are sug­gest­ing — that the im­pact trig­gered the vol­can­ism — does in fact rec­on­cile what had pre­vi­ously ap­peared to be an unimag­in­able co­in­ci­dence.”

AP

Pauline Dolovich, cen­ter, from Re­ich+Petch De­sign In­ter­na­tional and Siob­han Starrs, cen­ter right, from the Smith­so­nian work on the fos­sil at Re­search Cast­ing In­ter­na­tional in Trenton, On­tario, Tues­day Sept. 29.

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