This document discusses fluid inclusions and wall rock alteration related to hydrothermal fluids. It defines fluid inclusions as tiny samples of trapped fluid in minerals, and describes hydrothermal fluids as underground hot water rich fluids capable of transporting metals. Wall rock alteration is defined as the reaction of hydrothermal fluids with enclosing rocks, causing mineralogical changes. The document outlines different types of wall rock alteration including potassic, phyllite, carbonatization, tourmalinization, greisenization, and silication alteration. It concludes that alteration phenomena are effectively studied in igneous rocks where progressive clay mineral alteration may occur.

1. FLUID INCLUSION-WALL ROCK
ALTERATION
BY:
THOMAS CHINNAPPAN . A ,
M.SC.APPLIED GEOLOGY,
PERIYAR UNIVERSITY,
SALEM.

2. FLUID INCLUSION
• Fluid inclusions (FI) are tiny samples of fluid trapped in minerals,
either during their initial growth (primary inclusions) or later when
fractures in the host mineral heal in the presence of a fluid phase
(secondary or pseudosecondary inclusions).

3. • HYDROTHERMAL FLUID:
• underground hot water rich fluid capable of
transporting metals in solution
• It contain all types of dissolve minerals
• superheated water that remains liquid above boiling
point because of extreme high pressure condition.

4. WALL ROCK ALTERATION
• wall-rock alteration A reaction of hydrothermal fluids with enclosing
rocks, causing changes in mineralogy that are most marked adjacent
to the vein and become less distinct further away.

5. PHYSICAL EFFECT OF ALTERATION:-
• It include in recrystallization change in permeablity and color
• The recrystallized area is generally more permeable than the
unalterated rock suggesting that the ores owe their localizationto
increased permeability
• pastel colours are especially prominent around certain ore deposit
• pyrite is a standard alteration product around confind ore deposit
• pyrite causes a striking colour changes

6. TYPES OF WALL ROCK ALTERATION:-
POTASSIC ALTERATION:
• Potassic (k-sillicate)alteration is characterised by the
formation of new k-feldspar and/or biotite usually together
with minor sericite,chlorite and quartz
• Accessory amount of magnetite/hematite and anhydrite may
occur associated with the potassic alteration assemblage
• pyrite and minor chalcopyrite and molybdenite are the only
ore mineral associated with this alteration
• Not all k-feldspar alteration is characterised by the presence
of reddish colouration

7. PHYLLITE ALTERATION:
• This alteration style is the most common in a variety of
hydrothermal ore deposit and forms over a wide temparature range
by hydrolysis of feldspar to form sericite with minor associated
quartz, chlorite and pyrite
• phyllite alteration is associated with porphyry cu deposit but also
with mesothermal precious metal ores and volcanogenic massive
sulfide deposit in felsic rocks

8. CARBONATIZATION:
• Is the formation of carbonate minerals during alteration of rock as
dolomite in association with amphibolite siderite in a banded iron
formation or calcite in a granitic host
TOURMALINIZATION:
• medium or high temperature alteration associated with many tin and
gold deposit quartz-sericite-tourmaline veins and alteration common

9. GREISENIZATION:
• A process of hydrothermal alteration in which feldspar and muscovite
are converted to an aggregate of quartz,topaz,tourmalline and lepidolite
by the action of water vapor containing fluorine
SILICATION:
• silication is the conversion of a carbonate mineral or rock into a sillicate
mineral or rock it is the main process which accompanies the prograde
stage in the formation of polymetallic skarn deposit develop when a
fertile acidic magmatic fluid infiltrate a carbonate host rock

10. CONCLUTION:
• Alteration phenomena occur in various rock types but are perhaps
more effectively studied when found in igneous masses
• stock,flows,sills and dikes often provide the locale in which
progressive clay mineral alteration may take place
• Alteration study include field and laboratory investigation both
• Field study include geological mapping with instumental control and
on sufficient detail to significant alteration zones
• Laboratory techniques include microscopic and x-ray examination