SI
SI
discoversearch

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor.  We ask that you disable ad blocking while on Silicon Investor in the best interests of our community.  If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.
Gold/Mining/Energy : ISLAND-ARC RESOURCES IAR-VSE
 Public ReplyPrvt ReplyMark as Last ReadFilePrevious 10Next 10PreviousNext  
To: teevee who wrote (137)1/21/1999 9:43:00 PM
From: Dave R. Webb   of 186
 
The requirements to meet the definition of a type II kimberlite are incredible. These definitions are used by a very select group of petrographers who can make a life's work out of two or three rocks.

I'm not aware of any true type II kimberlites outside of South Africa (although I haven't followed this debate very carefully in the past year).

It is pretty tough to define the petrography of the host rock when you have a few mineral grains in several hundred thousand other grains. Other systems are hard to use as well. Classification schemes that rely on chemistries are hopeless as the chemistries of kimberlite are by definition inhomogeneous.

A number of assumptions have to be made concerning coexisting mineral suites for any of the PT work to be done, and in tills, this usually means working with individual mineral grains that can't in any way be shown to to be in any relationship with any other mineral.

Tough work, so we guess at the petrography.

I wouldn't attempt to apply a guess for a system that works for a rock type that can't be demonstrated to exist on the continent. It may be an old fashioned attitude, but if it hasn't been found before, and the old system works well, I'd be fairly careful in using a new system.

Dave
Report TOU ViolationShare This Post
 Public ReplyPrvt ReplyMark as Last ReadFilePrevious 10Next 10PreviousNext  

HomeMailHotSubjectMarksPeopleMarksKeepersSettings
Terms Of UseContact UsCopyright/IP PolicyPrivacy PolicyAbout UsFAQAdvertise on SI
© 2025 Knight Sac Media.  Data provided by Twelve Data, Alpha Vantage, and CityFALCON News