全世界の 冷静な／正味のing 13,000 years ago that 誘発する／引き起こすd the 絶滅 of the mammoths was 原因（となる）d by 古代の 火山の 爆発s and NOT meteor 衝撃s, 熟考する／考慮する shows

• e-mail

Earth 冷静な／正味のd 速く 13,000 years ago and the 推論する／理由 behind this is a 一連の 火山の 爆発s which 原因（となる）d the 普通の／平均（する） 全世界の 気温 to 減少（する） by 3°C, a 熟考する／考慮する （人命などを）奪う，主張するs.

It was 以前 believed that a meteorite 衝撃 was responsible, but a new 熟考する／考慮する has 設立する this to be incorrect.?

Previous theories were based on 地質学の findings which had incorrectly been せいにするd to 激しく揺するs 上陸 from space.?

However, new 分析 of the 激しく揺する sediments shows they instead （機の）カム from 深い within Earth and were 事業／計画（する）d to the surface 経由で violent 爆発s.?

Scroll 負かす／撃墜する for ビデオ??

Earth 冷静な／正味のd 速く 13,000 years ago and the 推論する／理由 behind this is a 一連の 火山の 爆発s which 原因（となる）d the 普通の／平均（する） 全世界の 気温 to 減少（する） by 3°C, a 熟考する／考慮する （人命などを）奪う，主張するs (在庫／株)

The world-冷静な／正味のing period is known as the Younger Dryas and is associated with 早期に human 植民／開拓者s and the 絶滅 of the woolly mammoth.?

熟考する／考慮する co-author Professor Alan Brandon, of at the University of Houston, said: 'This work shows that the geochemical 署名 associated with the 冷静な／正味のing event is not unique but occurred four times between 9,000 and 15,000 years ago.

'Thus, the 誘発する／引き起こす for this 冷静な／正味のing event didn't come from space.

'事前の geochemical 証拠 for a large meteor 爆発するing in the atmosphere instead 反映するs a period of major 火山の 爆発s.'

火山の 爆発s spread 粒子s into the atmosphere, which 反映する thermal energy from sunlight away from the surface.?

A period of '全世界の 冷静な／正味のing' can follow a 火山の 爆破 for one to five years, depending on the time でっちあげる，人を罪に陥れる and 規模 of the 爆発.

Co-author Professor Steven Forman, of Baylor University in the US, said: 'The Younger Dryas, which occurred about 13,000 years ago, 混乱に陥れる／中断させるd 際立った warming at the end of the last ice age.

'The Earth's 気候 may have been at a tipping point at the Younger Dryas, かもしれない from the ice sheet 発射する／解雇する into the North 大西洋 Ocean, 高めるd snow cover and powerful 火山の 爆発s that may have in combination led to 激しい Northern 半球 冷静な／正味のing.'

分析 of 化学製品s 設立する in the 国／地域 at?Hall's 洞穴 in the Texas Hill Country 設立する? traces of rare elements, 含むing?osmium, iridium, ruthenium, platinum, palladium and rhenium.

However, they were not in the '訂正する' 量s to have been 追加するd by a meteor or asteroid.

Instead, the geosignatures 示すd a 火山の origin, not extraterrestrial.??

Pictured, archaeological 穴掘りs at Hall's 洞穴. 専門家s exposed sediments for geochemical 分析 that （期間が）わたる from circa 20,000 to 6,000 years ago?

Lead author doctoral student Nan Sun also, of the University of Houston, said: The 署名 from the osmium isotope 分析 and the 親族 割合 of the elements matched that 以前 報告（する）／憶測d in 火山の gases.'

Co-author Dr Kenneth Befus also at Baylor University 追加するd: 'These 署名s were likely the result of major 爆発s across the Northern 半球, 含むing 火山s in the Aleutians, Cascades and even Europe.

The 専門家s say that the period of 冷静な／正味のing lasted around 1,200 years, far too long to have been 原因（となる）d by a 選び出す／独身 event.?

Professor Forman said: 'A?単独の 火山の eruptive 原因（となる） is an important 始めるing factor, but other Earth system changes, such as 冷静な／正味のing of the oceans and more snow cover were needed to 支える this colder period.

'This is not the first time scientists have looked at other explanations for the sudden 冷静な／正味のing.'

The 研究員s 疑問d their theory when 直面するd with the 証拠, but after 調査／捜査するing all possible explanations for the 冷静な／正味のing, the only viable explanation was a 火山の one.?

Professor Brandon said: 'I was skeptical.?We took every avenue we could to come up with an 代案／選択肢 explanation or even 避ける this 結論.

'A 火山の 爆発 had been considered one possible explanation but was 一般に 解任するd because there was no associated geochemical 指紋.'?

The findings were published in the 定期刊行物 Science 前進するs.