Geothermometry, Geobarometry & Isotope Studies Flashcards
Sequence of deposition of minerals
Paragenesis
Collection pr gathering of minerals or rock
Assemblage
Having a connection or resemblance with other mineral in certain temperature and pressure regime
Associated
The spatial distribution of paragenesis
Zoning
The spatial distribution of paragenesis
Zoning
Born beside
Paragenesis
Measurement of lavas, fumaroles, hot springs
Direct Measurement
Indicate the maximum crystallization temperature
Melting Point
Some minerals lose their volatile content at certain temperature
Dissociation
Transformation of some minerals crystal system to another is temperature dependent
Inversion Point
Minerals that form solid solutions unmix at specidic temperatures to yield distinguishable intergrowths
Exsolution
Melting Point of Albite
1104C
Melting Point of Stibnite
546C
Melting Point of Bismuth
271C
Exsolution of
Chalcopyrite - Bornite
475C
Exsolution of
Cubanite - Chalcopyrite
450C
Exsolution of
Bornite - Chalcopyrite
175-225C
similar to inversion and exosoution but applies more specifically to native metals
Recystallization
Recrystallization temp of
Cu
Ag
450C
200C
Quartz lose color at
240-600C
Fluorite lose color at
175C
indicate the approximate temp of formation of the crystals by the amount of contraction of the liquid, assuming that the liquid originally filled the cavity
Fluid Inclusion
heating the sample until heterogeneous fluid inclusion homogenizes
Filling Temperature (Minimum Temperature of Formation)
by the freezing point depression method
Total NaCL-equivalent salinity of the fluid
The minimum melting point
Eutectic Point
inclusion is opened up and direct tests are made on the liquid by optical properties
Composition of the ore-blearing fluid
inclusions formed in growing crystals, no leakage
Primary
with fracture & sealed again, records conditions of later hydrothermal stage
Secondary
looks like secondary, but the host crystal was fractured as the crystal was growing
Pseudosecondary
commonly based on mineral assemblage and composition information
Geobarometry
estimation of pressure condition at which a geologic material formed
Geobarometry
an element that has a nuclei that does not change spontaneously
Stable isotope
decays into daughter isotopes at known rates
Radioisotopes
amount of time needed for one half of radioactive parent to decay
Half-life
is any Pb from a rock or mineral that contains a large amount of Pb and a small amount of the radioactive progenitors of Pb
Common Lead
