Asteroid belt collision 470M yrs ago led to earth impacts

[silylene]

<p>Interesting story in the news:</p><p>http://www.redorbit.com/news/space/1614707/meteorite_shower_may_have_had_global_effect/</p><p>http://news.bbc.co.uk/2/hi/uk_news/scotland/highlands_and_islands/7795381.stm</p><p><br /><img src="http://sitelife.space.com/ver1.0/Content/images/store/9/3/1923ade6-9257-4260-a3d7-6de42e713aa1.Medium.jpg" alt="" /></p><table border="0" cellspacing="0" cellpadding="0" class="storycontent"><tbody><tr><td colspan="2"><div class="mxb"><h1>Tiny clues to collision in space </h1></div>

 

[MeteorWayne]

<p>I wonder what inspired the release of this article now. Slow news day?</p><p>The article in Nature Geoscience is from last Jaunuary!</p><p>&nbsp;</p><p id="cite"><span class="journalname">Nature Geoscience</span> <span class="b">1</span>, 49 - 53 (2008) <br />Published online: 16 December 2007 | <span class="doi"><abbr title="Digital Object Identifier">doi</abbr>:10.1038/ngeo.2007.37</span></p><p id="errorcor">&nbsp;</p><p class="category">Subject Categories: Palaeontology | Geochemistry </p><h2 id="atl">Asteroid breakup linked to the Great Ordovician Biodiversification Event</h2><p id="aug">Birger Schmitz¹, David A. T. Harper², Bernhard Peucker-Ehrenbrink³, Svend Stouge², Carl Alwmark¹, Anders Cronholm¹, Stig M. Bergstr&ouml;m⁴, Mario Tassinari¹ & Wang Xiaofeng⁵</p><div id="abs">Top<span class="hidden"> of page</span> <p class="lead">The rise and diversification of shelled invertebrate life in the early Phanerozoic eon occurred in two major stages. During the first stage (termed as the Cambrian explosion), a large number of new phyla appeared over a short time interval approx 540&nbsp;Myr&nbsp;ago. Biodiversity at the family, genus and species level, however, remained low until the second stage marked by the Great Ordovician Biodiversification Event in the Middle Ordovician period^1,^2,³. Although this event represents the most intense phase of species radiation during the Palaeozoic era and led to irreversible changes in the biological make-up of Earth's seafloors, the causes of this event remain elusive. Here, we show that the onset of the major phase of biodiversification approx 470&nbsp;Myr&nbsp;ago coincides with the disruption in the asteroid belt of the L-chondrite parent body&mdash;the largest documented asteroid breakup event during the past few billion years^4,⁵. The precise coincidence between these two events is established by bed-by-bed records of extraterrestrial chromite, osmium isotopes and invertebrate fossils in Middle Ordovician strata in Baltoscandia and China. We argue that frequent impacts on Earth of kilometre-sized asteroids&mdash;supported by abundant Middle Ordovician fossil meteorites and impact craters⁶&mdash;accelerated the biodiversification process.</p></div><p>MW</p> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>