Fluid inclusion are tiny bubbles trapped in a mineral. They are upto 10 micron in size.

1. Priya Verma
2nd semester
Msc Geology

2.  Fluid inclusion is a microscopic bubble of liquid &gases that is trappedin mineral .
 Range in size : 0.1- 1mm
 Visible in microscopic study
 Formed from defects in crystals during their growth which lead to the entrapment of
fluid in their surrounding.
 Trapped fluid maybe : liquid, vapour, or supercritical fluids.
 Host minerals are: Sphalerite, Cassiterite, Quartz,Calcite, Dolomite, fluorite , topaz
etc
 Somefeldspar in granite also contain fluid inclusion

4.  Vapour contains or liquid phase : H2O
 Gas phase: CO2,CH2,H2S,Cl,etc
 Solid phase: Na, K, Ca, Mg, Fe and their salt.
 E.g: NaCl

5. Classification of Fluid Inclusions:
It relates the timing of formation of the inclusion relative to that of the
host mineral (Bodnar, 2003). Based on their origin, fluid inclusions
are of following types:
• Primary
Secondary
• Pseudo secondary

6.  It is formed during the formation of the
enclosing crystal are primary in origin.
 Trapped along the growth zones and crystal
faces.
 Very good indicators of the condition of
crystallization.

7.  Trapped in the fractures which are developed after
the formation of host mineral.
 At the time of healing.
 Occur as trails or clusters
 Often cut across the grain boundaries.
 They can reveal the evolution of pressure,
temperature and chemistry of fluids.

10.  Trapped during formation of the host minerals.
 Occur along trails

11.  Commonly identified as primary or secondary on
the basis of detailed petrological study.
Single Crystal

12. Zoned crystal
• It provides important guides for identifying primary fluid
inclusion

13.  They are of 3 types:
Isolated,
Clustered,
Trail-Bound inclusion
• Isolated: Basically primary but additional criteria
are required to know about its principle nature.

14.  Clustered: typically comprised of a group of 10-20
neighbouring inclusions.
: may have quite different origins such as neighbouring
isolated cavities.
 Trail bound: It either remain confined to a single
mineral or cut across different grains or phases.

16.  Trapped fluid inclusions are sometimes modified because
of several processes subsequent to their trapping.
 It cause reduction in their volume, change in morphology
and often loss of originally trapped fluid.
 Some mechanisms are: Recrystallization
Stretching and Necking-down
Explosion Decrepitation
Leakage

17.  Sample Preparation
 Fluid Inclusion Petrography
 Microthermometry
 Raman Microprobe

19. Fluid inclusions provide a wealth of information on the
geofluids that influenced the petrogenesis of rocks.
Such inclusions provide important information:
Temperature of Entrapment of Fluid
Pressure of the Fluid System
Density of Fluids
Salinity of Fluids
Composition of Fluids
P-T History of the Sample
Gas Composition of the Inclusions

20.  The more direct uses of fluid inclusions in exploration
mainly rely on defining an empirical relationship between
some inclusion characteristic and mineralization.
 It is used for mineral exploration : for hydrothermal
deposits like, copper , gold, silver etc.

21.  If the hydrothermal fluid is highly saline, above
23% NaCl. Halite can crystallise upon cooling
with solid crystals present.
 Such fluids usually occur in porphyry copper
deposits or the core of igneous intrusion
derived fluid systems.
* Saline inclusions are less common.

22.  https://www.slideshare.net/VishakhaNathani
/fluid-inclusion-in-ores?qid=48e6bea9-
daff-4ddb-a8ff-
37262bdbceb0&v=&b=&from_search=2
 https://www.researchgate.net/profile/Kirtiku
mar_Randive/publication/275337661_Study_
of_Fluid_Inclusions_Methods_Techniques_and
_Applications