Exploring abrupt climate change induced by comets and asteroids during human history

Mahaney & Keiser 2013

Restored from the library fire 1/11/20

The breakup in space of a comet or asteroid prior to impact could produce a surface or oceanic impact by the largest object, and hundreds of smaller fragments could create air-bursts affecting an entire hemisphere (Bunch et al. 2012). Approximately 90% of all ejecta from the main impact would fall within five crater radii, although fine material is expected to be random distributed over a much larger area. Although the type of impact vehicle is still uncertain, the present theory (Napier 2010) is that a fragmented comet produced multiple impacts or airbursts over at least 10% of Earth, releasing an estimated 10 × 10 6 tonnes of Fe spherules (Wittke et al.2013)

Weathering Rinds as Mirror Images of Palaeosols

14 Responses

  1. I haven’t got an age yet for the weathered rinds on the fired rocks at Colvin Mountain, and Campbell Mountain in California; only a detailed PGAA analysis that strongly hints at ET origin for the burnt facies there. But volcanism as a heat source for the burnt, and fired rocks can be positively ruled out because the location has been volcanically stable since the early Mesozoic. And since the foothills on the western slope of the Sierra Nevada weren’t covered by glacial ice during the last couple of ice ages there is a strong potential for the weathering rinds on the rocks found there to contain a longer record of cosmic impacts than anything found in the Alps.

  2. Cool!

    Wide spread and easily accessed geological record of ET materials is certainly going to chaff a large part of the academic part of the geological profession.

  3. If anyone is interested, Adrian Melott has another Younger Dryas paper on the Arxiv this evening. Since I haven’t read it yet, obviously I am unable to comment on it, sorry. Just FYI.

  4. Hi

    The growing interest of geologists, and extension methods is the important thing.

    I think this 10% figure very modest. Considering the large surface of oceans, yet from what anyone can see in satellite photos around the world, and through the probable impactites I have collected in palaeolagoons in northeastern Brazil, I believe that Earth plunged into a cloud of cometary fragments. Most likely over 80% of the planet should achieved over several hours or days ….the last 13,000 years various cosmic events could occurred, which leaves the research even more interesting, in this mosaic of time and space.

    Yes, I would like to see data of the rings in the Andes, Himalayas, Ruwenzori ……


  5. So what has happened with the NOVA producers?
    Has Boslough been dragged over the coals yet?

  6. Hello Dennis –

    Fires on mountains in that region occur quite often.

    Many people have made the mistake of thinking that their
    current ground cover is the one that has always existed on them.

  7. Ed said:

    “Fires on mountains in that region occur quite often.

    Reality check:

    No matter the ground cover, no natural process of bio-mass burning is capable of producing the temperatures required to melt and fuse the weathered surface rinds of silicate rocks.

    But really Ed. Did you even bother to glance at the chemistry in that PGAA analysis?

    Ordinary forest, or brush fires also don’t produce an Iron and Nickel rich surface rind or glazes on those same silicate rocks.

    Rick Firestone did that PGAA analysis. He’s pretty sharp about such things. And ya know what? I’m thinkin’ he’d have been able to recognize if that specimen was the work of an ordinary forest fire. Heck you never know, he might have even said something when he sent me back the test results.

    But please don’t start trollin’ again Ed,

    Heck, you’re not a geologist, nor even a real academic or scientist with published works in a peer reviewed journal. And you’ve never even been there. My own academic standing is no better. But I on the other hand, grew up there.  So unless you can present a curriculum vitae or verifiable expertise to the contrary, I can’t help but assume that comparatively speaking, and with regards to the geology and geomorphology of my childhood home on the western slope of the Sierra Nevada Mountains, specifically the local mountains, and foothills west of Kings Canyon National Park that I’ve played in, hiked in, grew up in, and have studied passionately in all my life, you have not the remotest clue what you are talking about.

    Ed also said

    “Many people have made the mistake of thinking that their current ground cover is the one that has always existed on them.”

    Meanwhile, and in spite of having no direct personal knowledge of a place, still others will assume that they are prepared to argue about the geography, geology or geomorphology of that place with folks who’ve called it home for a lifetime.

  8. Dennis & Ed,

    I’ve read most of what both of you have written… you both are looking at the same issue from different directions (about 180 degrees out) and you are both are probably very correct about your observations and conclusions based on your positions and research. Why the hell you continue to bash each other regarding conclusions about each other’s work is beyond me. You are both working toward the same goal and some personality conflict continues to hose the substance of the conversation on this site. I know I don’t know enough specifics to post a lot of facts on this site, but I do spend a lot of time reading it and enjoy almost all of it… just not the bashing. CL’s crap is also pretty boring.

  9. The forensics keep coming in. Forensics wins cases in courts. Such evidence on the YDB keeps making the reasonable doubt exonerating any comets more and more doubtful… The lousy perps!

  10. Hi Dennis,

    Even if you have an impact melt layer, which I seriously doubt, you will still have to prove that it is timed to the Holocene Star Impatc Event.

    Aside from that, I need an old MacPro, an iPad, and about $10,000 to document a likely crater from the Holocene Start Impact Event.

    I am glad to see you admit that you known nothing about impact processes.

  11. I never said or wrote anything of the sort Ed. That’s your own frequently demonstrated poor reading comprehension skills causing you to misinterpret or read words that were never written, and assume content and meaning does not exist in the real world, biting you on the butt again. And since I agree whole heartedly with many of the top planetary scientists at NASA, who’ve dealt with your rude, insulting, self important, and demanding behavior for many years, and who tell me it’s best to simply ignore you, I really have no need, or desire to prove anything to you. As for your never ending panhandling for toys, and money. I for one have no help for insulting trolls who can’t keep their comments on topic and civil.

  12. Hey Ed, what about a Linux (Ubuntu) desktop? Any old WinXP desktop can be easily converted as long as the CD-ROM works. The OS is a free download, as is the Office variant (Open or Libre). A clean hard drive wouldn’t hurt either. Cheers –

  13. If Ed or Dennis posts again and I am breathing the post is gone. You are the most disappointing audience in the history of earth science.

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