Evidence suggests ancient impact crater buried under Bolaven volcanic field

Phys.org ^ | January 3, 2020 | Bob Yirka

[SunkenCiv]

A team of researchers with members from Singapore, the U.S., Thailand and Laos has concluded that the impact point of a meteorite that struck the Earth approximately 790,000 years ago lies buried beneath a volcanic field in southern Laos. In their paper published in Proceedings of the National Academy of Sciences, the group outlines four lines of evidence that point to the Bolaven volcanic field as the likely site of the meteorite strike.

Prior research has shown that approximately 790,000 years ago, a large meteorite (the largest known young meteorite impact) struck Earth in the Eastern Hemisphere. So great was the impact that debris was strewn across a tenth of the entire planet's surface. Scientists know about the impact because of bits of glassy clasts known as tektites have been found in places like Antarctica, Australia and Southeast Asia... the researchers have found evidence that suggests the reason the crater has not been found is that it is hidden beneath a volcanic field -- and they provide four lines of evidence to back up their claim.

...the geochemistry of the tektites in the vicinity of the Bolaven volcanic field -- the researchers claim it implies the presence of basalts at the impact site... geologic mapping and dating of basaltic lavas that existed before and after the time of the impact, which showed a change occurred around the time of the impact... gravity measurements the team took at the Bolaven volcanic field -- they report an anomaly that suggests the presence of a 13- to 17-kilometer crater... an outcrop of crudely layered sandstone and mudstone boulders 10 to 20 kilometers from the Bolaven volcanic field, which appear to have been thrown there by the force of the meteorite striking the ground.

[SunkenCiv]

The Bolaven Plateau volcanic field likely buries the impact crater that produced the tektites of the Australasian strewn field. It is the only adequately large and thick postimpact deposit on the Khorat Plateau, the largest region of plausible target rocks. It is also the only thick, postimpact deposit within the inner Muong Nong strewn field, the region containing exclusively nonaerodynamically shaped Muong-Nong-type tektites (circumscribed by the blue ellipse). Tektite find locations data from ref. 52 and this study. Basalt fields adapted with permission of ref. 53 and ref. 54; permission conveyed through Copyright Clearance Center, Inc. Outline of the Khorat Plateau data from ref. 55. Inset, finds of Australasian tektites and microtektites data from ref. 56 (white dots) define an asymmetric strewn field (blue). Credit: Proceedings of the National Academy of Sciences

[SunkenCiv]

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[dp0622]

That’s really not that long ago...in the 4 billion years scheme of things.

[Redcitizen]

Whoever was living there had a really bad day. Twice.

[BenLurkin]

Interesting

[SunkenCiv]

It was a great big owie.

[SunkenCiv]

sidebar:

Meteorite impact caused the highest temperature ever recorded on Earth’s surface
by Bob Yirka , Phys.org
SEPTEMBER 18, 2017 REPORT
https://phys.org/news/2017-09-meteorite-impact-highest-temperature-earth.html
https://scx2.b-cdn.net/gfx/news/hires/2017/earth.jpg
Credit: CC0 Public Domain

[Larry Lucido]

John Kerry says it’s seared, seared into his brain.

[jmacusa]

I believe that most of the lower half of the state of Florida, mostly in the area of the Everglades is the remains of an ancient impact crater.

[jmacusa]

Seared you say? If John Kerry says it seared I guess it’s seared. Seared I’m sure.

[dp0622]

Wow. Never knew that.

[txnativegop]

interesting, shows just how often Earth gets hit by something or other. Thanks SunkenCiv.

[jmacusa]

I remember some years ago, think it was on The Discovery channel either a separate meteorite hit that area after the massive meteorite that hit the present day Yucatan Peninsula or a chunk of that meteorite hit what is now the present Everglades are. I’m not an expert but it would seem to me to explain why there are often so many issues with sinkholes in the Everglades.

[dp0622]

That would make sense.

[Larry Lucido]

Did he mention he was in Cambodia?

[SunkenCiv]

Farfetched, since he has none. :^)

[SunkenCiv]

It's an interesting kaboom, and was formerly unfamiliar to me -- "debris was strewn across a tenth of the entire planet's surface".

[grey_whiskers]

You mean it *wasn’t* Soleimani?

[SunkenCiv]

Parts of him flew, just not fast enough to cover 1/10 the Earth's surface. :^)

[M-cubed]

John Kerry says it’s seared, seared into his brain. <<

along with the rice in his ass when he threw the grenade into the rice cache..,