Ore Dep 2 Flashcards
ore that is being deposited through direct crystallization of Magma.
Magmatic Segregation deposits
usually** formed in the magma chamber**, thus are deep-seated intusive bodies but are differentiated or immiscble melt and crystal mush can be derived into magma chamber walls or roof to orebodies that are dikes, sills and even extrusive flows.
Magmatic Segregation deposits
in Magmatic segregation, the ore is a product of early or late fractionation due to?
Gravitative setting
immiscibility
filter pressing
a large sill-like body of igneous rock which exhibits vertical layering or differences in composition and texture
Layered mafic Intrusions (LMI)
refers to the activity of oxygen and sulfur
(based on discussion)
Fugacity
the first to a reaction in LMI is?
Oxygen
in LMI, Chromium goes with?
Oxygen
in LMI, PGEs and Nickel goes with
Sulfur
occurs in plutonic igneous setting and appeared to be intruded into a more or less stable craton
Layered Cr-Pt Mafic-Ultramafic Complex
age of most economically important LMI
Proterozoic
LMI are layered with the average composition of?
Gabbro
there are ____ known layered igneous complexes in the world
8
out of the 8 known layered igneous complexes, only _____ have significant chronium
3
A Layered igneous complex that is mined for chromium.
Bushveld igneous complex
A Layered igneous complex that is mined for platinum.
Great Dyke
Bushveld igneous complex is found in
South Africa
Great Dyke is found in
Zimbabwe
Largest PGE resource
Merensky Reef
considered as the largest Cr resource, holding 70% of the world’s cr resource
Bushveld
90% or more of the intermediate to calcic plaioclase. it is also the source of almost all “hard rock” source of Ti
Anorthosite-Titanium
Largest Ni resource in the world
Sudbury (,canada)
2 types of An-Ti deposits
- Layered mafic intrusions characterized by Anorthite (An 70-100)
- Proterozoic “massifs” containing plag from Andesine to labradorite (An 35-65)
a volatile-rich, potassic ultramafic-related phreatomagmatic breccia pipe or igneous dike dominated by olivine, with subordinate minerals of mantle derivation.
Kimberlite
Kimberlites are first recognized in?
Kimberly, South Africa
Kimberlites are surprisingly ____________ assemblages
free of alteration
a jet of air is activated by photocelss that perceive visible light flourescene included in diamond by an x-ray beam as concentration moves along a V-belt.
Sortex Method
2 methods used to recover diamonds
heavy-liquid separation
Sortex Method
Cylindrical pipe-like bodies of calciye, dolomite and/or siderite that are prominently concentrically zoned.
Carbonatites
Carbonatites are mined for?
REE
2 general types of Carbonatites
Magnetite-apatite rich
REE-Fl-Ba-rich
Kimberlites occur in
Continental settings
Largest concentration of kimberlites can be found in
East African Rift system
Only ____% of kimberlites contain diamonds
1
greatest concentration of kimberlites can be found on rocks aged ?
Mesozoic Age
DIamonds in Kimberlites occurs as
Sparse Xenocrysts
a form of material degration occuring when the microstructure of some carbons and low alloy steels break down after long exposure to elevated temperatures
Graphitization
the partial or complete remelting or dissolution of a mineral by magma, resulting from changes in temperature, pressure or magma composition.
Resorption
Podiform chromite is also know as?
Alphine-type Chromite
ophiolite related which formed in mid-oceanic ridges or back-arc basin spreading centers & tectonically obducted onto continental or island arc margins
Podiform chromite
1st layers of ophiolite sequence
Deep sea siliceous or ocherous sediments with Radiolarian chert
2nd layer of ophiolite sequence
Layered pillow basalts cut by sheeted diabase dikes
3rd layer of ophiolite
Gabbro/norites + serpentinized flmafic to ultramafic rocks
An earthy usually red or yellow and often impure iron ore used as a pigment
Ocherous
Podiform chromite are form in
Structurally active area
Stratified chromite are form in
Stable craton
Podiform chromite is distributed in
Paleozoic or younger tectonic belts associated with convergent plate boundaries
Podiform chromite setting
Structurally complex setting with extensive post-ore deformation
Interpreted to be a product of interaction bett mantle harzburgite and an exotic magma
Podiform chromite with a dunite envelope
2 types of igneous iron deposit
(1) Volcano-sedimentary or sedimentary deposit
(2) intrusive magmatic segregation ore
Biggest iron skarn deposit in the Philippines.
Larap (or larap skarn deposit)
Most important intrusive iron ore deposit
Kiirunavaara Mine
Universally refers to high phosphorus iron ore
Kiruna type ore
