Silicon Investor (SI) -- The First Internet Community

STOCKTALK

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 : Nuinsco Resources (NWI) -- Ignore unavailable to you. Want to Upgrade?

To: LaFayette555 who wrote (1256)	3/6/1999 1:06:00 PM
From: E. Charters	Respond to of 5821

That is likely but quartz diorite is the identified animal that is the contact rock for many a nickel mine. By no means all of them, but it does turn up. It could be thought of as a porphyry of sorts. What is funny is the degree of silica in mines rocks in the Sudbury camp which was a source of much speculation. Strangely enough the rock that was the indicator for the Flin Flon camp was a quartz hornblende diorite or as the Hud Bay geos used to say, the QHD. A diorite could be an extremely altered gabbro. Wuite a few gabbros are altered to diorite on the surface. EC<:-}

To: LaFayette555 who wrote (1256)	3/6/1999 2:40:00 PM
From: Midas	Respond to of 5821

Francois: >I get mixed up trying to tell apart Diorite and Leucocrate Gabbro. Could a leucocrate gabbro be infact mistaken for a diorite in the field ??< The difference between Diorite and Gabbro can be quite difficult to determine in the field. Diorite is the intrusive equivalent of an andesite, and gabbro the intrusive equivalent of a basalt (Glossary of Geology, 1987). Mineralogically these rock types are quite similar except that diorite has plagioclase (feldspar) with more than 50% Na in the Na+Ca site of the crystal and gabbro has less than 50% Na (Streckeisen, 1976). The difference between these two rock types is relatively easy to determine in thin section using a microscope. In hand sample the darker color of plagioclase (specifically the minerals labradorite and bytownite) in gabbro may help to distinguish it from diorite. Labradorite also has a distinct schiller that may be visible if samples are studied with a hand lens. In summary, hand samples of diorite and gabbro can be difficult to classify correctly especially if the samples have plagioclase compositions close 50% Na or Ca. Midas