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:


ECROFI Iceland
     July 2-6

AOGS Singapore
    30 Jul - 4 Aug 2023

SGA Zurich Aug 2023

Comprehensive Geology Conference Calendar


Sphalerite should be a good host mineral for fluid inclusions and resist post-entrapment modifications.

All of these sphalerite samples are from sedimentary syngenetic carbonate hosted deposits, formed at low temperature. The much older Woodcutters deposit has been remobilized during folding and is cut by later quartz veins. The woodcutters sphalerite (red curve) shows a peak at 200 C which may be due to CO2 rich fluid inclusions, perhaps related to this later fluid event. 

Note that the decrepitation for samples 1104B and 1113B is quite intense and the results have been divided by 3 to fit this plot scale. Sample 1113B (cyan curve), from Fedjal Joum, was a mixture of baryte and sphalerite and this graph is probably dominated by the baryte decrepiutation. The intense peak at 630 C on sample 1104B from Bou Grine is unusual and cannot be attributed to baryte contamination, which would cause a peak at much lower temperature.

The high temperatures of sphalerite decrepitation of 350 - 400 C are inconsistent with the low temperature sedimentary origin of these deposits. Sphalerite samples can be used for comparison but not for formation temperature estimates without further research.

  all sphalerite


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