Topic 4 Flashcards
(23 cards)
denotes the presents of minerals without
considering the economic value
Mineral Occurrence
it is a mineral occurrence of sufficient size and grade with potential value
Mineral Deposit
a mineral deposits that is economically viable for extraction
Ore Deposit
a genetic origin where the mineralization occurs at the same time as the formation of the host rock
Syngenetic Origin
form after the host rock has already been deposited.
Epigenetic Origin
fractional crystallization processes can
concentrate metals (Ni, Cr, Fe, Pt, PGEs)
Cumulate deposits
late stage crystallization forms pegmatites and many residual elements are concentrated (Li, Ce, Be, Sn, and U)
Pegmatites
hot water (magmatic fluids)
heated by pluton, directly associated
with magma (Cu, Au, Mo, Sn)
Porphyries
hot water (fluids) derived from
meteoric and magmatic sources;(Au, Cu,
Sn
Vein
hot water associated with contact
metamorphism; also termed Contact
metamorphic (metasomatic) - deposits
formed at elevated temperatures by the
addition and subtraction of mineral and
rock material (metasomatism); Most often
developed at the contact of intrusive
plutons and carbonate / calcareous
sedimentary country rocks (Cu, Fe, Au,
Sn)
Skarn
undersea hot water flowing
to surface (Sedex-type Pb-Zn- Ag and VMS
Zn-Cu-Ag)
Exhalative
hot water flowing and reacting with
carbonate host (MVT-type Pb-Zn-Ag)
Epigenetic carbonate-hosted
weathering of primary minerals and transport by streams (Au, diamonds, Sn, Pt, chromite, etc)
Placer
90%+ of world’s iron tied up
Banded Iron Formation
minerals like gypsum, halite deposited
Evaporite deposits
a mechanism of separating and concentrating chemical constituents, as in nickel laterites, leaching of rock leaves residual materials behind (Al, Ni, Fe). In supergene copper and gold deposits, reworking of primary ore deposits remobilizes these metals (often over short
distances)
Weathering
sublimates like sulfur in volcanoes, and deposits of perlite as silica
Volcanic
minerals concentrated by regional metamorphism (orogenic type) gold and base-metals (Au, Zn-Pb)
Orogenic/ Metamorphogenic
refers to the type of rock that contains or
surrounds a mineral deposit or a geological
feature of interest
Host Lithology
developed at the contact of intrusives and
carbonate (limestone/dolomite) or calcareous sedimentary country rocks
Skarn Copper/ Iron/ Gold
at margins or proximal to intrusions
Sediment-hosted gold
hosted – hot water flowing and
reacting with carbonate host (best example is MVT-type)
Epigenetic carbonate
