[BR-Crater] Basalts near Black Rock

[save children]

You can see the outline of the northern half of BR and what is call the "other", Columbia River and Snake River basalts. Possible that a impact hit on this edge and created a new melt or there was a impact which then filled in with the "other" defined flood basalts in the area. Basalts can be easily age dated isotopically. I have seen photos of a river being filled with flood basalts and after erosion of the softer surrounding sediments, the basalt that filled the river is on a pedestal of softer sediments. 
 
http://www.semp.us/publications/biot_reader.php?BiotID=217   Figs. 4.19
Message: 1Date: Sun, 4 Jan 2009 16:36:19 -0800From: "Rick Maschek" <rickmaschek at hotmail.com>Subject: [BR-Crater] Columnar jointed rocks State of theResearch-January 2009To: <br-crater at thunder.net>Message-ID: <BAY116-DS434AD1DBF6F95C6E5B6CAA6E10 at phx.gbl>Content-Type: text/plain; charset="iso-8859-1" >From a post by Ian: "An interesting point is that we see these columnar jointed rocks at Black Rock at an elevation of around 4450 feet. Since they are all nearly the same elevation across the east and west sides of the playa (25 miles apart), it's an indicator of the possible impact melt pool in the suspected crater. It seems an extremely unlikely coincidence for a volcano to make a lava pool so big or to line up the elevations of similar but unrelated formations so closely. It also gives us an estimate of what elevation the crater floor might have been. That's about 500 feet above the current Black Rock playa. It goes to show how much of the suspected crater has been eroded away." I graduated in geology though I've spent the last 7 years teaching chemistry before retiring. Since I haven't looked at any geological maps of the area and only read Ian's "State of the Research - January 2009" and have only been to Black Rock for BALLS events, I can't really say much about this. In reading this I would like to ask (and I might be wrong) if the columnar jointed rocks on both sides of the playa match up and are thought to have been the melt pool at the bottom of this crater that made Black Rock Playa, where is a lower area that this 500' of material eroded to if the playa is the bottom of the crater? Also, it would be very easy to take a sample of this columnar jointed rock and have some geology student at some university take a good look at (thin section, mass spec, etc) very cheaply or for free. And getting an age date would be easy and inexpensive as well. Just a thought, Rick Maschek Charlie Wittman, Director, Advocates for Children and FamiliesCCHR Board of Advisors, theacf at hotmail.comPO Box 10, Los Gatos, CA 95031, Main ACF WWW site:: http://www.theacf.org CRIN: http://www.crin.org/organisations/viewOrg.asp?ID=1774 CCHR: www.cchr.orgNCFJwest, Divorce/child custody www.ncfjwest.orgKI6PQQLUNAR #1405, http://www.lunar.org Aero-Pac # 699 http://www.aeropac.org NAR [L2] #85655, http://www.nar.org Tripoli [L2} #11202 www.tripoli.org
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