Applied mineral exploration methods, hydrothermal fluids, baro-acoustic decrepitation, CO2 rich fluids
Newest Topics:

Forensic tests on soil samples

Gold at Okote, Ethiopia


Do IOCG deposits form from CO2 fluids?

How CO2 inclusions form from aqueous fluids (UPDATED)

Understanding heterogeneous fluids : why gold is not transported in CO2-only fluids

Gold-quartz deposits form from aqueous - CO2 fluids: NOT from CO2-only fluids

Discussions why H2 analysis by mass spectrometry is wrong


Kalgoorlie Au data

Sangan skarn Fe deposits, Iran

New model 205 decreptiometer

Studies of 6 Pegmatite deposits

A study of the Gejiu tin mine, China

Exploration using palaeo-hydrothermal fluids

Using opaque minerals to understand ore fluids

Understanding baro-acoustic decrepitation.

An introduction to fluid inclusions and mineral exploration applications.

 Interesting Conferences:


ECROFI 2021, Reykjavik, Iceland

SGA, Rotorua NZ, RESCHEDULED to march 28-31 2022
6th Archean, Perth, W.Aust. RESCHEDULED unknown date 2022

Comprehensive Geology Conference Calendar

Using fluid inclusion data in mineral exploration

Rapid data acquisition by the baro-acoustic decrepitation method

An overview of  information and results on using fluid inclusion information in exploration
Kingsley Burlinson
Burlinson Geochemical Services Pty. Ltd.
P.O. Box 37134,   Winnellie,  NT,  0821,     Australia
Ph. +61 411 443 097    (Within Australia  0411 443 097)
decrepitation  <at>

Skip down to:     CONTENTS       Case studies by deposit       Case studies by location  You can search this site here


Fluid inclusions are trapped remnants of the fluids which formed hydrothermal mineral deposits and provide a unique insight into the chemical and physical conditions  of ore forming fluids. Academic studies of ore deposit genesis have long relied on this vital fluid inclusion data to understand the genesis of ore deposits. But despite the obvious relevance of this information, the exploration community has largely failed to use this data in their routine exploration activities to target potentially economic hydrothermal systems.

Baro-acoustic decrepitation is a simplified method to obtain reproducible, non-subjective fluid inclusion data quickly and without the need for polished thin sections or microscopes. It can provide information about the source fluid environment and targeting vectors on project-scale numbers of samples, at modest price and with quick analytical turnaround. It does not provide fluid salinities or the pedantic levels of precision required in academia, but these aspects are not particularly useful in exploration and frequently just add confusion rather than resolution.

The most important use of baro-acoustic decrepitation is in determining approximate total gas contents of samples, as this data is frequently closely correlated with mineralisation potential. Examples in this documentation show this use as well as others including the  discrimination between samples which are visually identical and in discerning temperature zonation effects within a vein, mine or small exploration area. It can even be used on opaque minerals where microscopy is completely impossible, and many examples from iron oxide minerals are shown here.

The baro-acoustic decrepitation method was wrongly discredited by early work in the 1950's in Canada at a time when the presence of gas-rich fluids in hydrothermal systems was not understood and neither was the thermodynamic behavior of such fluids within inclusions. With the benefit of our currently much improved understanding of fluid systems it is now clear that baro-acoustic decrepitation does in fact provide a very useful and practical mineral exploration technique, particularly given the ability to digitally automate the instrumentation as has been done.

Baro-acoustic decrepitation is not intended to compete with the very high accuracy of slow and painstaking microscopic fluid inclusion research. However, as with soil geochemical surveys, where low cost and speed are more important than extreme accuracy, baro-acoustic decrepitation has a valuable role to play in many types of exploration programme. Although the method is usually applied to quartz samples, it has been used on various minerals including sulphides, haematite, magnetite, fluorite, carbonates and jasperoids.

An extensive database of some 5000 analyses from numerous ore deposits worldwide is the basis for the following information.



An introduction to fluid inclusions and their application in mineral exploration
Gold exploration using Baro-acoustic decrepitation
The decrepitation method - what is it and why use it?
Decrepitometry application to porphyry deposits (1981 report)
The fluid inclusion technique in exploration for Au mineralisation (Old report, 1982)

Sample collection techniques
Result interpretation
Decrepigram interpretation features
Using fluid inclusions in the opaque minerals haematite and magnetite
Fluid Inclusion Studies on Opaque Minerals
Customs information for sample entry to Australia
Selecting the best sample grainsize to use for decrepitation analyses
Forensic comparison or contrasting of soil samples
Using curve fitting to deconvolve the results to precisely identify multiple component sub-populations of inclusions
Using 3 software packages to de-convolve decrepigrams into component populations for quantitative interpretation
Using Baro-acoustic decrepitation data in exploration at the Drake mineral field, NSW and the application of curve fitting to the decrepitation data
Understanding baro-acoustic decrepitation
Why CO2-rich fluid inclusions decrepitate at low temperatures
Decrepitation behavior of all non-condensing gases are similar
Inclusion abundances and controls on decrepitation
Using baro-acoustic decrepitation to semi-quantitatively measure CO2 contents
Decrepitation ONLY detects fluid inclusions, it does not detect crystallographic changes.
Model 216 decrepitometer developed,2019.
Model 205 decrepitometer developed, march 2017.
The Model 105 decrepitometer - a brief description
Comparison of different decrepitation Instruments
Comparison of the Russian decrepitometer and the BGS model 105 decrepitometer.
Comparison of decrepitation with mass spectrometric gas determinations during heating

Explaining the formation of CO2-only fluid inclusions
Gold deposition from heterogeneous aqueous, CO2-rich fluids: resolving the enigmatic and misleading hypothesis of deposition from CO2 only fluids.
Gas dominated inclusion assemblages may be trapped from aqueous dominant heterogeneous fluids by disproportional trapping
The extreme differences between aqueous boiling heterogeneous fluids and immiscible gas aqueous heterogeneous fluids.
Spherical inclusion morphology of CO2 only inclusions indicates heterogeneous trapping from a liquid.
Fluid inclusions in quartz cannot prove that non-aqueous fluids CO2 formed the ore.
Why don't exploration geologists use or understand fluid inclusions? The case at the Cadia Au-Cu mine, NSW, Australia.
Hydrogen contents of fluid inclusion volatiles should not be analysed by mass spectrometer.
A model for the formation of H2 from water in the electron impact ioniser of the mass spectrometer
A discussion and reply on the error of using  mass spectrometry to analyse hydrogen in aqueous analytes.

Geochemical exploration using hydro-thermal fluids - a paper at the SGA conference, Uppsala Sweden, Aug. 2013
Fluid Inclusion Studies on Opaque Minerals - a paper presented at the ACROFI-4 conference, Brisbane QLD., August 2012
Gold exploration using Baro-acoustic decrepitation - a paper presented at the IMA, Budapest, 2010
Understanding baro-acoustic decrepitation - a paper presented at ACROFI-2, Kharagpur, 2008
Exploration for gold using fluid inclusions - a paper presented at the AAG conference, Oviedo, Spain, 2007.
An updated understanding of the baro-acoustic decrepitation method. (proposed for the ECROFI meeting, Bern, 2007)
Acoustic decrepitation as a rapid means of determining CO2 (and other gas) content of inclusion fluids and its use in exploration (Nanjing, 2006)
Fluid inclusions in mineral exploration - a paper presented at the AAG conference, Santiago, Chile, 2001.    Poster presentation

The use of fluid inclusion decrepitometry to distinguish mineralised and barren quartz veins in the Aberfoyle tin-tungsten mine area, Tasmania. (1983)   (abstract)      (full paper, pdf)

An instrument for fluid inclusion decrepitometry and examples of its application. (1988)  (abstract)       (full paper, pdf)

The recognition of variations in sample suites using fluid inclusion decrepitation - applications in mineral exploration (1988)   (abstract)    (full paper, pdf)

Decrepitation studies in gold exploration. A case history from the Cotan prospect, N.T., Aust.  (1991)   (abstract)   (full paper, pdf)

Comparison of decrepitation, microthermometric and compositional characteristics of fluid inclusions in barren and auriferous mesothermal quartz veins of the Cowra Creek gold district, New South Wales, Australia  By: J.A. Mavrogenes et. al., (1995)  (abstract)

Acoustic Decrepitation as a means of rapidly determining CO2 (and other gas) contents in fluid inclusions and its use in exploration, with examples from gold mines in the Shandong and Hebei provinces, China  (2007)   (full paper, html)

A discussion to point out errors in H2 analyses of fluid inclusion volatiles by mass spectrometry.  (2013)

Fluid types and their genetic meaning for the BIF-hosted iron ores, Krivoy Rog, Ukraine.  By Marta SoĊ›nicka  (2015) Extract (PDF file, 3.5 Mbyte) here

Mineral geochemistry of the Sangan skarn deposit, NE Iran: Implication for the evolution of hydrothermal fluid. By Fatemeh Sepidbar (2017) Extract (PDF file, 5.8 Mbyte)

Decrepitation related references in date order


Archaean & Proterozoic hosted quartz vein deposits
Western Australia
Victory mine, Kalgoorlie
Archaen gold - Kalgoorlie
Mt Charlotte, Kalgoorlie
Southern Cross

Northern Territory, Australia
Tanami and Arunta areas
Arltunga area
Tennant Creek

Pine creek (COTAN project)

Cosmo Howley

Ontario, Canada
Dome mine
Abitibi region, general

Palaeozoic sedimentary hosted deposits
Victoria, Australia
New South Wales, Australia
Meguma Terrane, Nova Scotia, Canada
Nevada, USA

Epithermal Deposits
El Penon, Chile
Favona vein, Waihi, NZ
Banksa Stiavnica district, Slovakia
Cukuralan, Turkey
Granite hosted & porphyry deposits
Hebei province, China
Shandong province, China
Kisladag, Turkey

  Orogenic / Structual gold-quartz systems
Motherlode, California, USA
Muruntau, Uzbekistan
Okote,  Ethiopia

Iron oxide - Copper - Gold deposits
Overview of FeOx-Cu-Au systems
Great Bear magmatic zone, NWT, Canada
Tennant Creek, NT, Australia
Magnetite and haematite decrepitation data
Mengku, northern Xinjiang, China
Magnetite at Krivoy Rog, Ukraine
Magnetite from the Bergslagen region, southern Sweden
Comparing and contrasting skarn and BIF magnetites

Hall porphyry Mo, Nevada
Mt Hope porphyry Mo, Nevada

Mt Bischoff, Tasmania, Australia
East Kemptville (Mt. Pleasant), Nova Scotia, Canada

Erzgebirge tin greisens, Germany - Czech Republic

Gejiu, Yunnan, China
Escondida, Chile
Chuquicamata, Chile

Malanjkhand, India
Chessy, France
Kapuskasing, Ontario, Canada
Black Bull, Nova Scotia, Canada
Mississippi valley type, Tunisia
El Laco, Chile
Krivoy Rog, Ukraine
Sangan Fe skarn,  Iran
Mengku, northern Xinjiang, China
Magnetite from the Bergslagen region, southern Sweden
Kola Peninsula, Russia

Nova Scotia
Kunming, China



Garnet (China)

Magnetite & Haematite

Magnetite & Pyrite

Magnetite at Krivoy Rog, Ukraine

Magnetite in skarns and BIFs


Tourmaline (China)



Northern Territory
Bynoe harbour (pegmatite)
Enterprise, Pine Creek
Pine creek (COTAN project)
Cosmo Howley
Tennant Creek
Tanami and Arunta
Arltunga area
Ballarat University grounds
Bendigo, Wattle Gully, Maldon
Woods point - the Morning Star mine
New South Wales, Australia
Cowra Creek goldfield
Western Australia
Greenbushes (pegmatite)
Archaen deposits - Kalgoorlie
Londonderry (pegmatite)
Mt Charlotte, Kalgoorlie
Victory mine, Kalgoorlie
Kalgoorlie area mines
Coolgardie area mines
Southern Cross area mines

New Zealand

North Island
Waihi,  Favona vein

North America

Abitibi area
Grenville (pegmatite)
Dome mine, Timmins
Kapuskasing carbonatite

        Tanco (pegmatite)
Northwest Territories
        Great Bear magmatic zone
Nova Scotia
        Black Bull Silica

        Mt. Pleasant Sn
        The Ovens

Getchell mine
Twin Creeks mine
Regional Jasperoids
Manhattan, Paradise Peak, Goldstrike
Hall porphyry Mo
Mt Hope porphyry Mo


Dongping, Hougou, Huangtuliang - Hebei
Jiaojia, Canshang, Sanshandao - Shandong
Mengku Feoxide - Xinjiang
Gejui and Kunming - Yunnan




Malanjkhand Cu

Middle east

                    Sangan Fe skarn,  Iran

South America

El Laco (iron)
El Penon

Europe  (including Turkey)

Chessy, Cu-Zn.
Massif Central (pegmatites)
Brusson Au

Germany - Czech Republic
Erzgebirge tin greisens, Germany - Czech Republic

        The Banksa Stiavnica eptihermal gold veins


        Bergslagen region, magnetite study

Cukuralan, Turkey
        Kisladag, Turkey

        Krivoy Rog, magnetite in BIF


 Tunisia - Bou Jaber, Bou Grine
Okote, Ethiopia


Kola Peninsula, Iron

  • Global comparisons

Comparing and contrasting magnetite skarns
A comparison of 6 pegmatite provinces - Sn, W & Ta deposits

K. Burlinson 2009, 2011, 2012, 2019
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