[meteorite-list] More on world sinkholes

From: Alexander Seidel <gsac_at_meteoritecentral.com>
Date: Tue, 01 Jun 2010 20:49:46 +0200
Message-ID: <20100601184946.199360_at_gmx.net>

Hi folks,

for those of you who can read and understand the German language I can strongly recommend an EXCELLENT book on this theme, one that has really thrilled me while I was reading it and looking at all those truly amazing photos. It was published quite a few years ago, but still seems to be available, with Uwe George as the author. It?s a GEO book. GEO in German/Germany somehow is what NATIONAL GEOGRAPHIC is in the English speaking world. Well, here we go:

<http://www.amazon.de/Inseln-Venezuela-Expeditionen-letzten-Flecken/dp/3570062120>

Best regards,
Alex
Berlin/Germany





-------- Original-Nachricht --------
> Datum: Tue, 01 Jun 2010 13:46:50 +0200
> Von: Zelimir Gabelica <Zelimir.Gabelica at uha.fr>
> An: meteorite-list at meteoritecentral.com
> Betreff: [meteorite-list] More on world sinkholes

> Listees,
>
> I was amazed and intrigued by the Guatemala
> sinkhole report, something that always fascinated me.
>
> There are larger such holes around the world,
> natural and not always filled by water.
> I remember having overflown by helicopter the 2
> famous big holes in the Sarisarinama region in remote South Venezuela.
> This was one of the most impressive views.
>
> Here are some links:
>
> 1) General about Sarisarinama:
>
> http://en.wikipedia.org/wiki/Sarisari%C3%B1ama
>
> 2) Views (click on clip 5):
>
> http://www.google.fr/imgres?imgurl=http://www.lastrefuge.co.uk/images/filmlibrary/sarisarinama_sink_hole.jpg&imgrefurl=http://www.lastrefuge.co.uk/data/aerials/tepuis_aerial_samples.htm&h=113&w=200&sz=11&tbnid=lwph4FMnj1IrnM:&tbnh=59&tbnw=104&prev=/images%3Fq%3Dsarisarinama&hl=fr&usg=__Kne9TnuqGa3DrTVz1sTqlK87wOw=&ei=NsAETPc6kb3iBuKH-MsO&sa=X&oi=image_result&resnum=3&ct=image&ved=0CCAQ9QEwAg
>
> 3) At the time (1995) it was forbidden to
> approach this site by some flying machine (no roads nor paths go there).
> On the way to El Paui gold mines (near the triple
> borderline Venezuela-Brazil-Guyana) with an
> expedition, we arranged with some local army
> official while in San Francisco de Yuruani, to
> have a short helicopter flight over the Sierra de Neblina/Sarisarinama
> sites.
> Breathtaking...
>
> Apparently there are now some organized tours
> offering tourists an overflow the area by some small plane of Cessna type.
> See here:
>
> http://www.google.fr/imgres?imgurl=http://www.condorjourneys-adventures.com/images/venezuela_sima_map.jpg&imgrefurl=http://www.condorjourneys-adventures.com/venezuela_sarisarinama.asp&h=270&w=299&sz=23&tbnid=zJqrcPIpjAMYwM:&tbnh=105&tbnw=116&prev=/images%3Fq%3Dsarisarinama&hl=fr&usg=__Zc1BSNFSQlulJEfpvqX4oo4qvBM=&ei=NsAETPc6kb3iBuKH-MsO&sa=X&oi=image_result&resnum=2&ct=image&ved=0CB4Q9QEwAQ
>
> Should you wish a less expensive trip, foresee a
> 17 days excursion and a very hard walking through jungle:
>
> http://www.abenteuer-venezuela.de/eng/Sarisarinama%20Expedition%20eng.htm
>
> But then you must be in an excellent health shape.
> In another expedition (2004), for having walked
> uphills through such a jungle from an improvised
> camp on the rio Churun tributary to rio Carrao,
> up to the bottom of the Salto Angel (Angel Falls
> 980 m high), I can just say such a walk it is
> more than hard but really rewarding and truly
> fascinating (especially when you eventually
> refresh under the highest natural shower in the world!)
>
> 4) This being, how the sinkholes work ?
> Look at this rather complete link, that includes,
> among others, the 2007 Guatemala sinkhole and the
> Sarisarinama geological Karstic-type collapse:
>
> http://science.howstuffworks.com/sinkhole.htm/printable
>
> 5) I agree with Werned Schroer that the pics
> showing the sinkhole in Guatemala City could be
> those recorded in Feb 23, 2007.
> See the above link but also a few pics in the
> link below, showing the 5-6 most famous sinkholes
> recorded worldwide, including....Sarisarinama
>
> http://www.environmentalgraffiti.com/offbeat-news/5-giant-holes-devoured-everything-around-them/1196
>
> Compare the outline of the Guatemala sinkhole
> that occurred in 2007 with that shown on the pic
> related to the last May 31 hurricane in the same city (preceding posts).
> Almost perfect matching!
>
> 6) To complete this issue it is also worth
> looking at the "7 amazing circular geological
> oddities in the world" (of all kind, natural,
> artificial, even of meteoritic origin). For "the
> beauty of art" or to complete your general geoinformation...
>
> http://travel.spotcoolstuff.com/united-states/arizona
>
> Have fun!
>
> Zelimir
>
> At 06:37 01/06/2010, Ryan Weidert wrote:
> >Cenotes are sinkholes, simply filled with water.
> >
> >Sinkholes are usually formed by the collapse of a void underground.
> >Typically this happens in limestone/marble/carbonate rocks (where
> >caves are normally formed) because rainwater + CO2 (dissolved in H20)
> >creates a weak (carbonic) acid that eats at the CaCO3 of the carbonate
> >rocks (as it seeps down cracks), and begins creating a gap. As the gap
> >gets larger, more water flows in, accelerating the process, until,
> >eventually, a cavity too large to support itself is created an
> >collapses, thus creating a sink hole.
> >
> >Similar processes occur within dirt, however instead of an acidic
> >water to eat at and remove rock, flowing water is all that is needed.
> >The report of a poor/leaking sewer system is a good indication that
> >this sinkhole is probably human caused. Basically, the leaking sewage
> >begins eroding the dirt around the pipe as it flows to wherever its
> >going. The void gets larger and more 'chunks' of dirt fall into the
> >moving water/sewage to be transported away. Since the hurricane just
> >went through, its a good bet that the sewers were inundated with
> >water, advancing the growth of the void to its collapse point.
> >
> >The neat thing about this sinkhole is how uniform and open it is. From
> >my observations, it seems that sinkholes that form in cites are
> >usually like this, as there is no rock to 'plug' the hole which would
> >only create a depression. This is indeed a big and deep one.
> >
> >A very neat place in New Zealnd is covered with sinkholes following
> >underground caves. A photo can be seen here
> >
> >http://davidwallphoto.com/searchresults.asp?t=45&n=25351
> >
> >cheers
> >ryan weidert
> >______________________________________________
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>
> Prof. Zelimir Gabelica
> Universit? de Haute Alsace
> ENSCMu, Lab. GSEC,
> 3, Rue A. Werner,
> F-68093 Mulhouse Cedex, France
> Tel: +33 (0)3 89 33 68 94
> Fax: +33 (0)3 89 33 68 15
>
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Received on Tue 01 Jun 2010 02:49:46 PM PDT