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

New model 216 decreptiometer

Exploration of the Mt. Boppy Au deposit, NSW

Forensic tests on soil samples


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


Gold at Okote, Ethiopia

Kalgoorlie Au data

Sangan skarn Fe deposits, Iran

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:


SGA, (Rotorua NZ), FULLY VIRTUAL march 28-31 2022
6th Archean, Perth, W.Aust. RESCHEDULED unknown date 2022

Comprehensive Geology Conference Calendar

Baro Acoustic decrepitation ONLY detects pressure pulses from fluid inclusions.

It cannot and does not detect crystal transition events.

The counts detected by the instrument are in fact pressure pulses which arise as fluid inclusions burst open when they reach sufficient internal pressure to overcome the confining strength of the host mineral. These pressure pulses are caused either by the release of gases such as CO2, or by the explosive boiling of superheated water into steam as the superheated water at high pressure is suddenly released into the 1 atmosphere environment in the apparatus. The sensor used is sensitive to pressure pulses in the air column of some 8 cm which separates the sample from the sensor.

pressure sense configuration

Because the pathway  between the sample and the sensor is through air, a fluid, shear waves generated by crystalline transitions in the sample are not detected. This is beneficial as it ensures that ONLY pressure pulses from the gas expansion as fluid inclusions explode are measured.

There have been comments made that the baro-acoustic decrepitation method only measures crystal restructuring events, such as dauphine twinning transitions in quartz. Such comments are completely wrong as crystalline transitions cause only shear waves in the quartz. And shear waves cannot be transmitted through the fluid (air) which isolates the sample from the sensor. Crystalline transitions cause only minute volume changes in the crystal which translate into minute pressure changes which are well below the detection limit of the pressure sensor.

July 2011

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