Chicxulub impact minute-by-minute

[TeethWhitener]

TL;DR Summary

A study published in PNAS of core samples from the Chicxulub impact crater gives a highly detailed account of that fateful day.

I saw this as part of Science Magazine's Breakthroughs of the Year:
https://vis.sciencemag.org/breakthrough2019/finalists/#A-killer
based on this study in PNAS (possibly paywalled):
https://www.pnas.org/content/116/39/19342

I had missed the paper when it first came out, and a quick skim of this forum didn't pull up anything. I found it fascinating, and I think others will as well.

From the Science website:

In 2016, the International Ocean Discovery Program drilled into the rugged hills around the center of the 193-kilometer-wide Chicxulub crater, which now lies mostly underwater on the Yucatán coast. The drilling extracted an 835-meter core, including 130 meters deposited the day the asteroid hit. An examination of the core, published this year, provides an almost minute-by-minute reconstruction of what happened after the impact. Molten rock filled the impact hole, followed by a hailstorm of debris. The ocean surged in, churning the deposits; then, by the end of the first day, a tsunami swept in more material, including charcoal from impact-induced wildfires. Even though sulfur-rich material was abundant at that site, there was little present in the core, suggesting it all vaporized and likely helped cause rapid global cooling and darkness.

Significance statement and abstract from PNAS:

Significance
Chicxulub impact crater cores from the peak ring include ∼130 m of impact melt rock and breccia deposited on the first day of the Cenozoic. Within minutes of the impact, fluidized basement rocks formed a ring of hills, which were rapidly covered by ∼40 m of impact melt and breccia. Within an hour, ocean waters flooded the deep crater through a northeast embayment, depositing another 90 m of breccia. Within a day, a tsunami deposited material from distant shorelines, including charcoal. Charcoal and absence of sulfur-rich target rocks support the importance of impact-generated fires and release of sulfate aerosols for global cooling and darkness postimpact.
Abstract
Highly expanded Cretaceous–Paleogene (K-Pg) boundary section from the Chicxulub peak ring, recovered by International Ocean Discovery Program (IODP)–International Continental Scientific Drilling Program (ICDP) Expedition 364, provides an unprecedented window into the immediate aftermath of the impact. Site M0077 includes ∼130 m of impact melt rock and suevite deposited the first day of the Cenozoic covered by <1 m of micrite-rich carbonate deposited over subsequent weeks to years. We present an interpreted series of events based on analyses of these drill cores. Within minutes of the impact, centrally uplifted basement rock collapsed outward to form a peak ring capped in melt rock. Within tens of minutes, the peak ring was covered in ∼40 m of brecciated impact melt rock and coarse-grained suevite, including clasts possibly generated by melt–water interactions during ocean resurge. Within an hour, resurge crested the peak ring, depositing a 10-m-thick layer of suevite with increased particle roundness and sorting. Within hours, the full resurge deposit formed through settling and seiches, resulting in an 80-m-thick fining-upward, sorted suevite in the flooded crater. Within a day, the reflected rim-wave tsunami reached the crater, depositing a cross-bedded sand-to-fine gravel layer enriched in polycyclic aromatic hydrocarbons overlain by charcoal fragments. Generation of a deep crater open to the ocean allowed rapid flooding and sediment accumulation rates among the highest known in the geologic record. The high-resolution section provides insight into the impact environmental effects, including charcoal as evidence for impact-induced wildfires and a paucity of sulfur-rich evaporites from the target supporting rapid global cooling and darkness as extinction mechanisms.

EDIT: full citation for posterity:
PNAS September 24, 2019 116 (39) 19342-19351

 

[BillTre]

@TeethWhitener: Always nice to see a good Chicxulub impact post.

I have made several posts on things related to the dinosaur killing Chicxulub impact.
They are kind of scattered and not easy to find.
There are posts (#3 and #5) in this thread with several references to other PF posts on the subject.

Recently there has been news of:

• detailed impact timing (which you posted on),
• details of the effects on North American environment and sequence of events in one of the most interesting fossil finds ever (PF thread here), and
• on the effects of the impact on ocean acidification (and marine extinctions) vs, the effect of the Daccan traps eruptions. (also this thread).

Because this information is so scattered, I have been making a continuing effort to link them all together (this post is an example).

This all really paints a very interesting and remarkably detailed view of what happened, about 65 million years ago, in a random, but important point in biological history.

You might say it was an impactful event.

 

[berkeman]

Because this information is so scattered, I have been making a continuing effort to link them all together

Time for an Insights article, maybe?

 

[Keith_McClary]

based on this study in PNAS (possibly paywalled):
https://www.pnas.org/content/116/39/19342

Free here:
https://www.researchgate.net/publication/335722192_The_first_day_of_the_Cenozoic

 

[newlook]

All attention has been given to what happened after impact. My question is what did the Earth look like before impact? My thinking is there was a different orientation of the planet that had a profound effect on what followed.

 

[phinds]

All attention has been given to what happened after impact. My question is what did the Earth look like before impact? My thinking is there was a different orientation of the planet that had a profound effect on what followed.

Is that in any way backed up by science or it it just a whimsical idea of your very own? You HAVE, I hope, read the rules on this forum against personal theories.

 

[Frabjous]

There is an old thread on this https://www.physicsforums.com/threa...-changed-Earth's-orbit-or-axis-at-all.400794/