[meteorite-list] Orbicular granite and chondrites

From: Elton Jones <jonee_at_meteoritecentral.com>
Date: Sat Sep 10 20:14:52 2005
Message-ID: <432376BF.3080704_at_epix.net>

Kevin Forbes wrote:

> Hi list,
> has anyone ever seen orbicular granite?

yes it is a popular dimension stone for construction

> Is the formation of this material related to the formation of chondritic
> meteorites in any way?

NOPE--can't even stretch a connection as to similar formation.
Chondrules apparently formed molecule by molecule out of primordial,
proto-solar-disk "soup" flash melted by really huge lightening bolts


Orbicular granite is a partial remelt of older granitoid material --
rarely country rock of other igneous or metamorphic origin. The loosely
spherical objects seen are referred to as zenoliths. If the orbicular
granite hadn't been suddenly chilled -- had the process ran to
completion, the zenos would have been reintegrated into the
average/existing composition of the surrounding material. The result
would have been regular texture granite. Perhaps the rain of zenoliths
into the melt took away too much of the available heat and the activity
came to a fast halt in mid-process.

Elton
Received on Sat 10 Sep 2005 08:13:51 PM PDT