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

How CO2 inclusions form from aqueous fluids

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

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

Inclusion shapes can prove heterogeneous FI trapping

Disproportional FI trapping from heterogeneous fluids explains gas-dominant systems

A discussion of H2 analysis by mass spectrometry

A mechanism to form H2 in the MS ioniser during analyses


News:

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:


AGCC expo, Adelaide, Aust. Oct. 14-18 2018

-----2019-----

ECROFI, June 24-26, Budapest, Hungary

AOGS, Singapore, 28 Jul-2 Aug 2019

SGA, Glasgow Scotland, Aug. 27-30 2019


Comprehensive Geology Conference Calendar


A Fluid Inclusion acoustic decrepitation study

Shandong province Au mines, China

Kingsley Burlinson, Jan 2006


Samples were collected from the mines visited on the SGA conference field trip to Shandong area Au mines in August 2005 and analysed by acoustic decrepitation. This method is useful as an exploration tool and particularly good at rapidly identifying CO2 rich fluids in the hydrothermal fluids which formed the quartz.

The map shows the mines sampled, which were: Linglong, Sanshandao, Canshang and Jiaojia. All of these are within granitoid intrusives. Only a few background samples from quartz veins distant from the mines were aable to be sampled.

    








The main observation from my results is that the depositional fluids in all of these mines lack CO2. If CO2 is present in the fluids, the decrepitation results show a distinct peak between 200 and 300 C, as you can see on the examples from Archaean deposits on the third graph. This lack of CO2 also occurs at Muruntau and the Motherlode deposits in California and so I infer that these deposits share a similar fluid genesis. In general, fluids derived from metamorphic zones greater than lower greenschist facies would be expected to contain significant levels of CO2. The formation temperature of the Shandong area deposits was about 360C to 380C.

Of all the samples analysed, only sample h1916 from the Canshang pit (purple plot below) showed a trace content of CO2. This is seen as the small decrepitation increase at 250C, but this is probably less than 1% CO2 content. The formation temperatures are about 380C.


     


Sample Details

H1908  Sample# 1855B  Ch05a  0.5g 
Linglong mine  Hillside (roadcut)  qtz veins in granite. Coarse milky white qz

H1912  Sample# 1856C  Ch05a  0.5g
Sanshandao mine - discovery outcrop. Coarse milky white qz

H1919  Sample# 1858D  Ch05a  0.5g 
Canshang openpit  Quartz sulphide ore zone down in pit. Massive milky white qtz and pyrite

H1916  Sample# 1858A  Ch05a  0.5g 
Canshang openpit  down in ore zone, north end. Milky white/grey qz, massive, trace S=


Individual mine results

Linglong Mine area




Sample details:

H1907  Sample# 1855A  Ch05a  0.5g  -420+200u
Linglong mine  Hillside (roadcut)  qtz veins in granite. Coarse milky white qz, pinkish feldspars
                                                                                               
H1908  Sample# 1855B  Ch05a  0.5g  -420+200u
Linglong mine  Hillside (roadcut)  qtz veins in granite. Coarse milky white qz
                                                                                               
H1909  Sample# 1855C  Ch05a  0.5g  -420+200u
Linglong mine  Hillside (roadcut)  qtz veins in granite. Coarse milky white qz


Sanshandao Mine



Sample details:

H1910  Sample# 1856A  Ch05a  0.5g  -420+200u
Sanshandao mine bottom stope at 430 m level. Grey/white coarse milky qz, sericite
                                                                                               
H1911  Sample# 1856B  Ch05a  0.5g  -420+200u
Sanshandao mine bottom stop at 430 m level. Grey/white coarse milky qz, sericite, trace galena
                                                                                               
H1912  Sample# 1856C  Ch05a  0.5g  -420+200u
Sanshandao mine - discovery outcrop. Coarse milky white qz


Canshang Openpit Mine



Sample details:

H1913  Sample# 1857A  Ch05a  0.5g  -420+200u
Canshang openpit  Mullock quartz at rim. Massive white semi transl. qz, trace S=
                                                                                               
H1914  Sample# 1857B  Ch05a  0.5g  -420+200u
Canshang openpit  Mullock quartz at start of ramp down. Massive white semi transl. qz
                                                                                               
H1915  Sample# 1857C  Ch05a  0.5g  -420+200u
Canshang openpit  Vein in hangingwall gneiss, part way down ramp. Grey-white translucent qz





Sample details:

H1916  Sample# 1858A  Ch05a  0.5g  -420+200u
Canshang openpit  down in ore zone, north end.  Milky white/grey qz, massive, trace S=
                                                                                               
H1917  Sample# 1858B  Ch05a  0.5g  -420+200u
Canshang openpit  down in ore zone, north end. Coarse granular grey/white qz
                                                                                               
H1918  Sample# 1858C  Ch05a  0.5g  -420+200u
Canshang openpit  down near ore zone, just below ore. Translucent grey massive qtz, weakly banded
                                                                                               
H1919  Sample# 1858D  Ch05a  0.5g  -420+200u
Canshang openpit  Quartz sulphide ore zone down in pit. Massive milky white qtz and pyrite
                                                                                               
H1920  Sample# 1858E  Ch05a  0.5g  -420+200u
Canshang openpit  Quartz sulphide ore zone down in pit. Coarse granular grey/white qtz with much S=







Sample details:

H1921  Sample# 1859A  Ch05a  0.5g  -420+200u
Canshang openpit ore dump; from bottom of pit at 170m depth 3.08 gm average?  Massive semi transl white/grey qz
                                                                                               
H1922  Sample# 1859B  Ch05a  0.5g  -420+200u
Canshang openpit ore dump from pit bottom at 170m depth. 3.08 gm average?  Massive semi transl grey qz
                                                                                               
H1923  Sample# 1859C  Ch05a  0.5g  -420+200u
Canshang openpit ore dump from pit bottom at 170m depth. 3.08 gm average?  Massive semi transl grey qz
                                                                                               
H1924  Sample# 1859D  Ch05a  0.5g  -420+200u
Canshang openpit ore dump from pit bottom at 170m depth. 3.08 gm average?  Coarse milky wh and semi transl. grey qz, much pyrite
                                                                                               
H1926  Sample# 1859E  Ch05a  0.5g  -420+200u
Cangshung open pit, Qtz/S= ore zone dumps from bottom of open pit at 170m depth. Coarse granular white/grey qtz with much S=


Jiaojia Mine

None of the samples from this mine contained any CO2. The sub-ore grade sample from the ore margin (h1940, purple line) is not recognisably different from the samples within ore grade, confirming that the ore boundary is not the result of different fluid events but is a grade cutoff within a single hydrothermal system. The ore system formed at about 360 C. Sample 1941 (yellow line) is from barren quartz at the road stop in granodiorite distant from the mine. This sample contained a substantial amount of  CO2, as seen by the peak at 180C.


Sample Details

H1929  Sample# 1860C  Ch05a  0.5g   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zone in footwall main fault, >1.5g/t grade
coarse grained qtz/feldspar, dark greenish grey, trace S=

H1930  Sample# 1860D  Ch05a  0.5g  Acid Washed
Jiaojia mine, 270m level, stope 6, ore zone in footwall main fault, >1.5g/t grade
coarse grained qtz/feldspar, dark greenish grey, trace S=

H1935  Sample# 1860J  Ch05a  0.5g  Acid Washed
Jiaojia mine, 270m level, stope 6, ore zone in footwall main fault, >1.5g/t grade
coarse grained qtz/feldspar, dark greenish grey, trace S=

H1940  Sample# 1861B  Ch05a  0.5g   ACID WASHED
Jiaojia mine, 270m level, stope 6, alt zone just outside ore zone 1.5 g/t cutoff
Coarse pink quartz-feldspar, feld. dominant, much S= on fractures
                                                                                                                 
H1941  Sample# 1862A  Ch05a  0.5g
Stop 7, Guojialing granodiorite o/c - almost no qtz veins or fractures
Massive milky white drusy quartz, open space growth textures





Sample details:

H1927  Sample# 1860A  Ch05a  0.5g  -420+200u
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=
                                                                                               
H1928  Sample# 1860B  Ch05a  0.5g  -420+200u
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=
                                                                                               
H1929  Sample# 1860C  Ch05a  0.5g  -420+200u   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=
                                                                                               
H1930  Sample# 1860D  Ch05a  0.5g  -420+200u   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=
                                                                                               
H1931  Sample# 1860E  Ch05a  0.5g  -420+200u   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=
                                                                                               
H1932  Sample# 1860F  Ch05a  0.5g  -420+200u   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=
                                                                                               
H1933  Sample# 1860G  Ch05a  0.5g  -420+200u   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=
                                                                                               
H1934  Sample# 1860H  Ch05a  0.5g  -420+200u   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=






Sample details:

H1935  Sample# 1860J  Ch05a  0.5g  -420+200u   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark greenish grey, trace S=
                                                                                               
H1936  Sample# 1860K  Ch05a  0.5g  -420+200u   Acid Washed
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, light grey
                                                                                               
H1937  Sample# 1860L  Ch05a  0.5g  -420+200u
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Coarse grained qtz/feldspar, dark grey with pink feldspar
                                                                                               
H1938  Sample# 1860M  Ch05a  0.5g  -420+200u      ACID WASHED
Jiaojia mine, 270m level, stope 6, ore zn in footwall main fault, >1.5g/t grade. Pinkish feldspar with subordinate dark grey qtz, trace S=





Sample details:

H1939  Sample# 1861A  Ch05a  0.5g  -420+200u      ACID WASHED
Jiaojia mine, 270m level, stope 6, alt zone just outside ore zone 1.5 g/t cutoff. Coarse quartz-feldspar, dark grey qtz and pinkish feldspars
                                                                                               
H1940  Sample# 1861B  Ch05a  0.5g  -420+200u      ACID WASHED
Jiaojia mine, 270m level, stope 6, alt zone just outside ore zone 1.5 g/t cutoff. Coarse pink quartz-feldspar, feld. dominant, much S= on fractures



Background barren quartz




Sample details:

H1941  Sample# 1862A  Ch05a  0.5g  -420+200u
Stop 7, Guojialing granodirite o/c - almost no qtz veins or fractures. Massive milky white drusy quartz, open space growth textures
                                                                                               
H1942  Sample# 1862B  Ch05a  0.5g  -420+200u
Stop 7, Guojialing granodirite o/c - almost no qtz veins or fractures. Milky white drusy quartz with much pink feldspar


Reference samples from other gold mines

Low CO2 examples from Muruntau and Motherlode, contrasted with high CO2 samples from archean areas in West Australia, Ontario and Quebec.





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