Glassy debris points to relatively recent asteroid impact in southeast Asia

Science Magazine ^ | January 3, 2018 | Katherine Kornei

[SunkenCiv]

A kilometer-size asteroid slammed into Earth about 800,000 years ago with so much force that it scattered debris across a 10th of our planet's surface. Yet its impact crater remains undiscovered. Now, glassy remains believed to have come from the strike suggest the asteroid hit southeast Asia as our close ancestors walked the Earth...

Aaron Cavosie, an astrobiologist and geochemist at Curtin University in Perth, Australia, and his colleagues examined the chemical composition of three tektites from Thailand. They searched for evidence of reidite, a rare mineral formed only by extreme pressures and temperatures, like those of an asteroid impact. But the team had to infer that reidite had existed: It disappears just seconds after it forms and transforms into zircon, a mineral common in Earth's crust...

The scientists studied tiny crystals of zircon in the tektites and looked at their geometrical orientation. They found that the crystals, each about half the width of a human hair, exhibited three different orientations intersecting at roughly right angles, consistent with laboratory and theoretical results that show how zircon transforms into reidite and then back into zircon. On the other hand, zircon crystals that have never converted to reidite tend to all be oriented in one direction.

The former presence of reidite in these tektites means that they were exposed to crushing pressures and searing temperatures... This discovery, paired with the generally large masses of tektites found in Thailand, is consistent with the impact occurring somewhere in Southeast Asia, the team reports in Geology. Other researchers have found evidence of a high-pressure version of quartz in some tektites, but reidite is a better tracer of a nearby impact, Cavosie and his team argue. "Reidite requires substantially higher shock pressures to form," Cavosie says.

[SunkenCiv]

An artist's representation of a large impact on Earth. [John R. Foster/Science Source]

[SunkenCiv]

I’d read about it before today, apparently:
http://www.freerepublic.com/focus/chat/2281004/posts?page=11#11

from the late William Corliss:

Australasian tektites coughed up by a moon of jupiter?
Science Frontiers Online
No. 67: Jan-Feb 1990
https://www.science-frontiers.com/sf067/sf067g12.htm

[SunkenCiv]

I read about the strewnfield in one of the very similar pages written by this crank:

Australasian strewnfield | Asteriod 2010 GD37 (1.26 km) is NOT EXPECTED TO HIT EARTH in December 2019 - and NO, NASA did not issue an impact warning! | Robert Walker | Debunking Doomsday | Quora

[SunkenCiv]

---

join or quit view topics view or post blog bookmark post new topic subscribe

---

[freedumb2003]

Caveman caused global warming to blame.

[SuperLuminal]

Orthogonality strikes again?

Maybe fantasies or wishful thinking or dwindling grants are enhanced by orthogonality...