General U-Peg info
Map
Formation
Fun facts!
100
The three MINERALS that make up most of the U-pegmatites composition.
- quart
- biotite
- k-feldspar
100
(Earth 231, 2021)
This zoomed in photo of the U-Pegmatite outcrop contains 3 minerals. What are they?
White, hardness 7 and conchoidal fracture
Black, hardness 5.5 and 2 cleavage planes at 60/120
Brown, hardness 2.5, and one perfect plane.
Quartz, Hornblende and Phlogopite.
100
3 stages in the sequence of deposition
1. Pegmatitic granite stage
2. Metasomatic replacement stage
3. Hydrothermal vein stage
100
Where is pegmatite found in North America
Canada and Brazil
In the world, the most abundant source is found in Australia!
200
This process occurs to pegmatite and leads to the redistribution of radioactive components after the magmatic stage has occurred.
What is hematitization or oxidation?
200
(Earth 231, 2021)
What is the main difference between the composition of the left and right?
Left: More mafic component, ex hornblende (black). Right: more felsic components, ex potassium feldspar (pink).
200
Based on the geological outcrop (QR Code)
State what is the oldest formation?
Amphibole Schist (Oldest)
200
Pegmatites can be used for commercial, gemstone, and construction applications name some!
Commerical- electronic products
Gemstone- jewlery
Construction- outdoor paving / landscaping
300
Granophyric texture occurs when there is an intergrowth of these minerals.
-feldspar
-quartz
300
(Earth 231, 2021)
Which area has the highest abundance of Uranium?
Count 6
300
How did the uranium come about into the outcrop
Hydrothermal calcite-fluorite veins may carry uraninite and uranothorite
300
Is there only one kind of Pegmatite?
Nope! many different kinds out there. It is based on the main minerals found. Like in granites the main minerals are Quartz Feldspar and Mica.
There can be tourmaline pegmatite, gabbroic pegmatite etc.
400
Why we shouldn't take Uranium Pegmatite for Granite?
Given Uranium Pegmatite's rare formation: partial melting, fractional crystallization, and volatile phase separation were responsible for the enrichment of uranium... In North America, it is only found in Brazil and Canada. The Bancroft outcrop is quite small which makes Uranium pegmatite even rarer!
400
(Earth 231, 2021)
(Earth 231, 2021)
This U-Pegmatite outcrop is dominantly quartz, hornblende, feldspars and mica. With this in mind, how do you think these minerals are distributed in the following picture?
Left: Quartz, hornblende, mica and potassium feldspar.
Right: Quartz, potassium feldspar.
400
(Earth 231, 2021)
What does the banding on the south side of the outcrop mean?
Foliation of different rock layers or separation of contrasting minerals during the cooling process
400
What is the meaning of pegmatite?
comes from the Greek word "pegnymi", which means "to bind together," referring to the interlinked feldspar and quartz crystals.