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

Nevada deposits, including jasperoids

CO2 in Nevada

The Au deposits in Nevada are young and in contrast with typical archaen deposits they lack any significant  CO2 in their fluid inclusions. The samples from these 3 deposits, as well as jasperoid style deposits in Nevada, all lack any significant low temperature CO2 decrepitation peak.


Jasperoids - Nevada  1

There are numerous jasperoid outcrops in eastern Nevada, most of which are simply surficial silicification, but some of them are gold mineralized and formed from hydrothermal fluids. Decrepitation can be used as a screening procedure to discriminate between these two types of jasperoid.

The Cranovitch and Jaydee pits are small gold deposits in the Robinson district. The Purple vein deposit, in the Carlin district, was an exploration prospect when this drillcore was sampled in 1990. See the adjacent figure for some surface results at Purple Vein. An example of typical background jasperoid from near the Easy Junior mine shows the contrast between the mineralized and barren jasperoids.


Jasperoids - Nevada  2

Within known deposits, most but not all samples decrepitate. Two samples from the Purple Vein deposit show the range of decrepitation which can occur, sometimes over quite small distances. Some 50 samples of background jasperoids were collected in eastern Nevada and almost all of these had no decrepitation. The North Easy ridge sample is one of the few from outside of a known mine which did decrepitate. Samples from close to but not actually within mines also show no decrepitation activity indicating that there is almost no detectable anomalous aureole outside of the mineralized zone itself. Although decrepitation does seem capable of discriminating between potentially mineralized and barren jasperoids, a high sampling density is required to compensate for the lack of aureoles around the mineralized zones.

    Back to Main Contents