I think I should jump in the car and head North huh., Crystal Falls.,
say doesnt Kennecott Minining have their main office there. I dont
know for sure. Well., Walt is probably better versed at describing
Kimberlite varieties., I think he has seen about everyone in the book.
weathered kimberlite breaks down into Serpentine., so it is soft in nature. Ultramafic rocks are generaly dark volvcanic rocks that are
over 90% composed of dark material. Picrite being one represenative of Ultramafic rocks main components are pyroxene and olvine.,
with combinations of honblendes., biotite., and magnetites. Secondary alterations of minerals in picrites alter them to serpentine
and chlorites., so grey to black picrites can take on black and greenish tints. Kimberlite is believed to be either picrites or a picrite
derivative with texture fine to medium grain but not always., and is
usually fragmented with colors varying from greenish to grey-bluish.
So the major components of kimberlite are olvine., pyroxenes and
phlogopite. During kimberlite emplacement many times xenoliths
occupy a portion of the kimberlite. Wall rock can play havoc in kimberlite emplacement. So what you would like to see in these
companies reporting kimberlite intersections are pure kimberlite without wall rock., xenoliths diluting the cores.
Walt could probably detail the differnt types and the reasons better
than I but I think you will find there are many types., each deposit
may have its intrinsic and geologic models inherent to the host rocks
the intrusions emplaced.
When I have more time., we will go over group I and group II kimberlites and what some of the general characteristics to both.
Sincerely
George J. Tromp |
