shandong, China gold Au

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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A Fluid Inclusion acoustic decrepitation study

Shandong province Au mines, China

Kingsley Burlinson, Jan 2006

Sample Details

Individual mine results

Linglong Mine area

Sample details:

Sanshandao Mine

Sample details:

Canshang Openpit Mine

Sample details:

Sample details:

Sample details:

Jiaojia Mine

Sample Details

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Background barren quartz

Sample details:

Reference samples from other gold mines

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