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

Gejiu tin mine and Yunnan regional area, China

Sample details and descriptions, September 2014

Sample numbers are 2029 to 2036.
Analytical analysis numbers are H2751 to H2766.

Kafang Underground

h2751 Sample# 2029A Ch14 0.5g -420+200u
Kafang underground tin mine, Gejiu Garnet from adit
brown, banded garnet skarn, no acid reaction NAR

h2752 Sample# 2029B Ch14 0.5g -420+200u
Kafang underground tin mine, Gejiu fine grained grey basalt
fine grained grey ???basalt?? very acid reactive, much CO3=

Dadoushan active open pit

h2753 Sample# 2030A Ch14 0.5g -420+200u
Dadoushan open pit, Gejiu skarn limestone very acid reactive
fine grained grey limestone skarn with thin bands of tourmaline

h2754 Sample# 2030B Ch14 0.5g -420+200u
Dadoushan open pit, Gejiu skarn limestone very acid reactive
fine grained grey limestone skarn with thin bands of tourmaline (lower pit lvl)

h2755 Sample# 2031 Ch14 0.5g -420+200u
Dadoushan open pit, Gejiu skarn limestone acid reactive, ACID WASHED
massive black tourmaline

Baishachong disused adit

h2756 Sample# 2032A Ch14 0.5g -420+200u MAGS
Baishachong pit, Gejiu skarn at granite/limestone contact ferruginous
vitreous dark brown/black ferruginous haem/mag, weakly magnetic, MAG fraction/

h2757 Sample# 2032B Ch14 0.5g -420+200u MAGS
Baishachong pit, Gejiu skarn at granite/limestone contact ferruginous
vitreous dark brown/black ferruginous haem/mag, weakly magnetic, MAG fraction

h2760 Sample# 2032C ch14 0.5g -420+200u MAGS
magnetite skarn at granite/ls contact, Baishachong pit gejiu
black ferruginous skarn, weakly mag only, mag separates

h2761 Sample# 2032D ch14 0.5g -420+200u WEAKLY MAGS
magnetite skarn at granite/ls contact, Baishachong pit gejiu
black ferruginous skarn, weakly mag only, mag separates

h2762 Sample# 2033A ch14 0.5g -420+200u MAGS NAR
garnet magnetite skarn Baishachong pit gejiu same locn as 2032
brown/black ferruginous skarn, weakly mag only, mag separates

h2763 Sample# 2033B ch14 0.5g -420+200u NON-MAGS NAR
garnet magnetite skarn Baishachong pit gejiu same locn as 2032
brown/black ferruginous skarn, weakly mag only, NON-mag separates

Regional background (remote, unmineralised)

h2764 Sample# 2034 ch14 0.5g -420+200u AR
Ridge east of Dali. fine grained Limestone, unaltered.
fine grained grey massive limestone

h2765 Sample# 2035 ch14 0.5g -420+200u AR
Mt Changsha, ridge west of Dali. Clean white limestone - sample from collection
medium grained clean white limestone

h2766 Sample# 2036 ch14 0.5g -420+200u AR
Near Lufeng, China. Shallow marine carbonate
fine grained pale grey limestone outcrop AR

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NAR means No Acid Reaction with 10% HCl
AR means Positive Acid Reaction with 10% HCl

Microscope observations on crushed grain samples

2030A   h2753 Dadoushan open pit, limestone with tourmaline
            5% tourmaline grains, white fine crystalline carbonate microcrystals 1/10 grainsize, hackly fracture to grains.

2036    h2766   Lufeng   No decrepitation
            grey opaque very fine grained limestone, not crystalline, smooth surface grains

2034    h2764   east Dali ridge
            pale grey and grey fine limestone crystalline grains, can see cleavages albeit small crystals, granular grain surfaces, some grains semi-translucent.
            crystals < 1/20 grainsize

2033B   h2763   non-mags Baishachong adit
            50% haematite grains, 50% translucent ?qtz?? but maybe mostly garnet? many translucent grains are "greasy" cream grains - garnet!!
            15% qtz, 30% garnet 5% opaque white/grey, no acid reaction. garnet uncertain - maybe epidote.
            no composite grains.   Possibly andradite or epidote - yellowish mineral with Ca.

2031    h2755   tourmaline   Dadoushan open pit
            >98% tourmaline, but possible rare qtz overgrowths on some grains
            50% black tourmaline, 50% translucent pale yellowish / colourless. Good crystal striations on all grains
            no significant mineral contamination. No (or almost no) composite grains

2029B   h2752   supposed basalt Kafang underground mine
            Abundant pale grey grains of ?limestone? fine grained   Some fine grained tourmaline, substantial f.g.garnet NO ferromagnesian minerals
            not recrystallized.
            This sample cannot be basalt as claimed during the mine visit.