Hi Alan and all,
Is not the description/s part of the classification so that the researcher can better describe what is found without having to baffle over a number or preset definition that might...kind of...come close to what is found??
Jim On 4/12/2014 10:01 AM, Alan Rubin wrote:
Since Van Schmus and Wood (1967), the group/petrologic type designation has been entrenched (i.e., LL3.0, H4, L6), that it would be impossible to purge. So, calling Semarkona LL T3 just won't work -- no one would adopt it as a new convention. If we wanted to call Semarkona LL3.00 A2.8, that might be okay, but you would have to convince people first that a two-tier system is needed. It is probably best to exclude weathering and shock stage since we cannot designate every property in a classification (e.g., average olivine Fa content, cosmic-ray exposure age, oxygen-isotopic composition, chondrule size, etc.). A problem of course is that it may be difficult to disentangle thermal metamorphism from aqueous alteration, leaving a researcher baffled as to what to designate a particular rock. It would be better to leave out a classificatory parameter and to just guess and have the rock misclassified. Alan Rubin Institute of Geophysics and Planetary Physics University of California 3845 Slichter Hall 603 Charles Young Dr. E Los Angeles, CA 90095-1567 office phone: 310-825-3202 fax: 310-206-3051 e-mail: aeru...@ucla.edu website: http://cosmochemists.igpp.ucla.edu/Rubin.html
-- Jim Wooddell jim.woodd...@suddenlink.net http://pages.suddenlink.net/chondrule/ ______________________________________________ Visit the Archives at http://www.meteorite-list-archives.com Meteorite-list mailing list Meteorite-list@meteoritecentral.com http://six.pairlist.net/mailman/listinfo/meteorite-list
