[BR-Crater] Crater Impact Research, I have an Analysis lab....

[Owen DeLong]

This information has been relayed to Ian by telephone.

The team is entering the Sierras en-route to Reno to rendezvous with
Tom, then will proceed to the campsite where Bob and Moni are expected
to meet the team.

Owen

On Sep 5, 2008, at 12:33 PM, Pat Barthelow wrote:

>
> Raffie, Ian, Owen, and Group:
>
> Some (most) of the examinations of rock samples for evidence of  
> Crater impact origins are microscopic, involving Electron  
> Microscopy,xray diffractioin,  and other expensive technologies to  
> examine.  I am developing a working relationship with some of the  
> world's best at analyzing site samples, and particularly microscopic  
> examination of samples, to evaluate whether the sample site history  
> involves cratering events.  I got an offer by a world renowned  
> research lab to microscopically, (including electron microscopy/X  
> ray diffraction, etc) examine samples that we may bring back from  
> Black Rock Desert, if they show promise for further examination.
>
> So if you collect samples for further examination, be sure to  
> METICULOUSLY take notes, digital pictures, GPS coordinates, depth,  
> orientation, etc  and keep a chain of custody (numbering, packaging,  
> storage)  of the samples, and I can facilitate their expert  
> examination by a world renowned lab...
>
> At the end of this email I include a detailed summary of Criteria  
> for determination of impact structure origins of a sample;  
> Microscopic, Macroscopic, and Megascopic.. it is interesting reading.
>
> Have fun, Be Safe...
>
> Pat Barthelow  AA6EG   aa6eg at hotmail.com
>
>
> Earlier message sent:
>
> I sent this to the groups, but it was intercepted for Moderator  
> review, and did not get posted.
> Perhaps because Ian is on his way already..
> Take a look... it is a rich resource on Cratering Geology, etc.
> If you think it is worthwhile reference material, perhaps you can  
> post to the groups, directly.
> Timliness may apply here, as the reference material applies directly  
> to the Black Rock study.
>
> All the best,
> Pat Barthelow   (916) 315-9271; aa6eg at k6bj.org
> Jamesburg Moonbounce Team
> http://www.jamesburgdish.org
> http://www.greatdanepro.com/Blue%20Bueaty/index.htm
>
> From: aa6eg at hotmail.com
> To: team at stratofox.org; invitees at stratofox.org; br- 
> crater at thunder.net; aa6eg at hotmail.com
> Subject: PBS show, resources Re Crater Science
> Date: Thu, 4 Sep 2008 18:11:25 -0700
> Today, (Thursday) on KVIE, the Sacramento PBS channel was a Science  
> program particularly relevant to the study of the Black Rock Crater.  
> Try to catch it on your Local PBS channel:
> http://www.pbs.org/exploringspace/
>
> The program featured Dr. Richard Grieve; Chief Geoscientist, Earth  
> Sciences Sector, NRC, Ottawa, re Impact cratering processes, and: Re  
> Asteroids; Doomsday Rocks, Impact Craters:
> See:
> http://query.nytimes.com/gst/fullpage.html?res=9D0CEED7103EF93BA25755C0A967958260&sec=health&spon=&pagewanted=2
>
> Dr. Richard Grieve, also of the Department of Energy, Mines and  
> Resources in Canada
> compiles a list of confirmed asteroid craters, the total now  
> standing at 131.
> The list grows by five or six a year. A crater in south Australia is  
> 100 miles across. The largest found so far, measuring 124 miles from  
> rim to rim, is in Ontario.
>
> Very rich resource for research and eduction re impact craters:
> http://www.lpi.usra.edu/publications/
> Click on Books: Traces of Catastrophe the AMLAMP Project
> Great, Relevant Chapters:
>
> http://www.lpi.usra.edu/publications/books/CB-954/chapter1.pdf
> http://www.lpi.usra.edu/publications/books/CB-954/chapter7.pdf
> http://www.lpi.usra.edu/publications/books/CB-954/chapter8.pdf
> http://www.lpi.usra.edu/publications/books/CB-954/chapter3.pdf
>
> All the best,
> Pat Barthelow (916) 315-9271; aa6eg at k6bj.org
> Jamesburg Moonbounce Team
> http://www.jamesburgdish.org
> http://www.greatdanepro.com/Blue%20Beauty/index.htm
>
> *******************************************
> Criteria
>
>    The principal criteria for determining if a geological feature is  
> an impact structure formed by the hypervelocity impact of a  
> meteorite or comet are listed below. The criteria can be divided  
> into megascopic (overview – bird’s eye / satellite scale),  
> macroscopic (can be seen easily seen with the naked eye) and  
> microscopic (requires a microscope to see) features, as follows:
>
>   1.
>      Presence of shatter cones that are in situ (macroscopic  
> evidence).
>   2.
>      Presence of multiple planar deformation features (PDFs) in  
> minerals within in situ lithologies (microscopic evidence).
>   3.
>      Presence of high pressure mineral polymorphs within in situ  
> lithologies (microscopic evidence and requiring proof via X-ray  
> diffraction, etc.).
>   4.
>      Morphometry. On other planetary bodies, such as the Moon and  
> Mars, we rely on the shape of the impact structure to determine its  
> presence and type (simple versus complex, etc.). This is a  
> megascopic quality (i.e., too big to be seen unaided by the human  
> eye, thus requiring remote sensing, aerial photography, detailed  
> mapping of multiple outcrops to assemble and view the typically km-  
> or multiple km-size structure). On Earth, recognizing impact  
> structures solely by their morphometry is complicated by two  
> factors: (a) weathering, erosion, burial processes and tectonic  
> deformation can obscure and/or destroy the original shape; (b)  
> certain terrestrial features generated by means other than impact  
> can have comparable circular form (e.g., volcanoes, salt diapirs,  
> glacigenic features), such that a circular structure alone is not  
> sufficient to claim impact structure status. Some buried craters  
> have been revealed solely by geophysical techniques, although drill  
> core is typically required to reveal macro- and microscopic evidence  
> to prove an impact origin.
>   5.
>      Presence of an impact melt sheet and/or dikes, and impact melt  
> breccias that were generated due to hypervelocity impact  
> (macroscopic). These bodies typically have a crustal composition  
> derived by the fusion of target rocks (i.e., there is no mantle  
> contribution to the melt). Such melts may be contaminated by  
> meteoritic (projectile) components (the latter requires specialized  
> geochemical analysis to detect the projectile components). Melt  
> sheets may be overlain by so-called fallback breccias (referred to  
> as “suevite” by some workers), and material blasted out of the  
> crater may form ejecta blankets about the original central cavity.  
> For large impact events, ejecta can be distributed globally. Impact  
> melt sheets are recognized by careful mapping and rock sampling  
> followed by microscopy and geochemical analysis.
>   6.
>      Pseudotachylyte and Breccias: Pseudotachylyte is a rock type  
> generated by faulting at either microscopic or macroscopic scales.  
> However, pseudotachylytes are also associated with seismic faulting  
> due to endogenic processes (e.g., earthquakes due to isostatic  
> rebound and plate tectonics), so they are not exclusively impact  
> generated. However, in association with features listed above, they  
> can be a contributory criterion. Pseudotachylyte associated with  
> impact structures may form in radial and concentric fault systems  
> that help to define the megascopic structure of the crater.  
> Pseudotachylytes can be included in a family of rocks referred to as  
> breccias. Many different types of breccia can be developed as part  
> of the impact process (including impact melt breccias listed in (5)  
> above), but breccias can also form by endogenic processes. The  
> interpretation of breccias therefore requires considerable care and  
> experience. Moreover, they should not be considered diagnostic of  
> impact, but rather contributory evidence.
>
>    In terms of relative importance, it is generally considered that  
> criteria 1-3 above are definitive (they all relate to the passage of  
> a shock wave through rock and resulting modification processes),  
> with contributory evidence being added by 4-6 (which result from  
> secondary effects, such as gravitationally driven crater  
> modification). For buried structures that cannot be directly  
> accessed, but are well-preserved as revealed by detailed geophysical  
> techniques (especially seismic data), some workers consider this as  
> strong evidence in favour of an impact origin. Normally, buried  
> craters are verified by drilling and sampling the material directly  
> for evaluation using criteria 1-3 above.
>
>
>