A PETROGRAPHIC REPORT

Size: px

Start display at page:

Download "A PETROGRAPHIC REPORT"

Eunice Norman
5 years ago
Views:

1 . 1 ~ A PETROGRAPHIC REPORT Prepared For: Dr. Eric Hoffman (}eneral~anager ACTIVATION LABORATORIES LTD. October 16, 2003 APR by: Eva S. Schandl Ph.D. GEOSC1ENCE ASSESSMENT

2 OBJECTIVES The objectives of this petrographic study were: (a) to identify the Cu-sulfide(s) in the suite of two rocks and (b) to identify all other sulfides and the gangue minerals present. CONCLUSIONS Sample 1 is a coarse-grained monomineralic rock, consisting of only galena. In sample 2, massive chalcopyrite is the predominant Cu-rich sulfide, and it makes up ca. 15% of the polished thin section. A few minute ( I-Im) bornite inclusions occur in some of the chalcopyrite. The only other sulfide identified in the sample is, disseminated and fragmented fine-grained marcasite. Much of the marcasite has been replaced by late Fe-oxide. The gangue minerals in sample 2 are quartz and carbonate. Although quartz is partly recrystallized, the outline of relict euhedral quartz (by minute fluid inclusions) suggests that they originally filled vugs. The fine-grained carbonates occur as equigranular aggregates. Late Fe-oxide (with fine-grained jarosite?) cross-cuts all sulfides. The complete absence of sphalerite in the two polished thin sections is puzzling. Finally, the presence (and abundance of) fluid inclusions with variable liquid/vapor ratios in quartz suggests that boiling has probably occurred during the hydrothermal evolution of the rocks. This can be only verified however, with fluid inclusion microthermometry, which could determine the temperature and salinity of the mineralizing fluid.

3 Sample Number: 2 Rock Type: Sulfides Petrographic Description: The sample consists predominantly of galena, lesser chalcopyrite, marcasite, quartz, carbonate and Fe-oxide (oxyhydroxide). The massive sulfide is contained in vug-filling quartz and fine-grained carbonate. Late Fe-oxide veins cross-cut the sulfides and some contain fine-grained jarosite Blocky, coarse-grained, massive galena that makes up ca. 75% of the sample (in the polished thin section), is characterized by growth bands and some deformation. Concentric growth bands in individual grains are outlined by triangular pits. Some massive grains contain blocky, fine-grained marcasite veins. Massive, anhedral chalcopyrite is in contact with galena. Small, anhedral chalcopyrite grains are included in coarse-grained galena, and some of the chalcopyrite are partly intergrown with galena. As small galena inclusions also occur in chalcopyrite, the crystallization of the two sulfides was probably more or less contemporaneous. Marcasite is relatively common in the rock. It occurs as anhedral, fragmented aggregates, some of which are brecciated and some are partly replaced by Fe-oxides, which form a network of vein lets, cross-cutting all sulfides. Coarse-grained galena contains a few spear-shaped marcasite inclusions, and chalcopyrite also contains finegrained, marcasite inclusions. Textural evidence suggests that marcasite was probably present in the rock prior to the crystallization of galena and chalcopyrite. The blocky marcasite veins which occur in galena, were probably inherited from an earlier protolith. The only gangue minerals in the sample are; fine-grained carbonates and vugfilling quartz. The carbonates occur as equigranular aggregates and the vug-filling quartz are semi-prismatic. Galena and chalcopyrite also occur as small veinlets within fractured quartz, suggesting that their crystallization post-dated quartz. Small fluid inclusions in quartz, having variable liquidlvapor ratios suggest that the metals were probably deposited during boiling. This however, can only be substantiated by microthermometry. Mineral % grain size Galena 74 avo 3 mm Chalcopyrite 15 < mm Marcasite 3 Quartz 5 < mm Carbonate 1 <1 mm Fe-oxide 2 amorphous 2

$fractures in galena. Width of field: 4mm.$ '-. ":, 4 : '. Sample 2: !

4 Sample 2. Chalcopyrite (yellow) is intergrown with galena (cream color). Note small chalcopyrite inclusions along fractures in galena. Width of field: 4mm. Reflected light....,..' ~ " ~.~ ~;~' -. '-. ":, 4 : '. Sample 2: Chalcopyrite (yellow) is intergrown with!~alena (cream color). Width of field: 4mm. Reflected light...?-.,,, 1.

$v\fidth of field: 2mm. ' Reflected Lig ht.$ *i.--:. ~:-~. ~~.: ~ j~~ /.: _i~ '!JA-~.

5 Sample 2. Minute bornite (purple) in chalcopyrite. v\fidth of field: 2mm. ' Reflected Lig ht. <I'.., ~,, ;,..,':f.9 f/~',.....,.;~~p'! *i.--:. ~:-~. ~~.: ~ j~~ /.: _i~ '!JA-~.~ Sample 2. Granular marcasite (white) in Fe-oxide matrix (gray) adjacent to massive chalcopyrite (It. yellow). Width of field: 4mm. Reflected light..1,-..,,-

6 Sample 2. Fine-grained carbonate aggregates adjacent to massive galena (black). Width of field: 4mm. Crossed nicols. Sample 2. Coarse-grained galena (entire photo) wi1th growth bands outlined by triangular pits. Width of field: 4mm. Reflected light.

7 ,..... Sample 2. Fluid inclusions in quartz. Variable vapor/liquid ratios suggest boiling. Width of field: O.4mm. Ppl. Sample 2. As above...._.,

8 Sample Number: 1 Rock Type: Massive galena Petrographic Description: The sample consists of 100% coarse-grained galena. Individual grains are outlined by the triangular pits. Some grains show evidence of growth bands, weak deformation and fracturing. Sphalerite is conspicuously absent from the ore. 3

::09:g' ::::!:lcd :::: 3 (i)(i)-o U::JCD CD.- O:.

$.::J CD CD ::JO:. or cc I.. '~..... ~. ~i. \.$ $~,> ~\. ~~'. "~' ~., ' :,.- - ::::::!. ::J OlO:.$ ~~: co:. -c Ol Ol..., - -Occ ;:+..., :" en Ol.

9 ::09:g' ::::!:lcd :::: 3 (i)(i)-o U::JCD CD.- O:.en~ c.q' ~ () :::::J-O 0 :+"CDOl en..., en Ol CD ::J I O:.CC..., o ~. ::::::!.::J CD CD ::JO:. or cc I.. '~..... ~. ~i. \.~:;~~< o CD '. ::I,.'. ~ ~ i ~~"~. ~ Ol ~~, '.~,> ~\. ~~'. "~' ~., ' :,.- - ::::::!. ::J OlO:. ~~: co:. -c Ol Ol..., - -Occ ;:+..., :" en Ol. :J :E en -.Ol.-CD 0."" :::::JO:. o CD ~~ :=!'! :J' CD CD 0:. 0:. ".. C" ~'< 3.- 3ffi

10 08115/05 MON 07:42 FAX l4j 002 Report of Petrology Conducted on Rock sample #52928 For Explorers AHiance Corporation l~ Lionel bonhomme August 2005 AUG 1 ::l ZOOS ~UG 1.~_?005 08: 40 '--'-~'-.'.'--' "-',..,.. "._, PAGE.d2

11 ~~ : :40 PAr3E.03 08/15/05 MON 07:42 FAX 1,.tJ 003 INTRODUCTION In JW1e Peter Calbick visited the property located in Delhi township to collect samples. Following this. a Declaration Of Assessment Work Report was filed with the Ministry Of No~ern Development and Mines. In October Lionel Bonhomme of Explorers Alliance Corporation produced a portion of sample #52928 to Actlabs. in order to conduct a petrograhic study. This report, authored by Dr Eva Schendl, has been filed for Assessment work W , however it lacked sample Identification #. Therefore, a copy of a previous description and location js attached to comply with a 45-day notice.

$t'r'rs f.. 1-8465 ~\ ",/.. ~ X '.(.. :......i:" '.$ $1 m Q lfl Q Q (\J f'~1 100 ~ 0 r=-...; - E=i -:J.3.$

12 t'r'rs f ~\ ",/.. ~ X '.(.. :......i:" '... ". "'- -- J TH 4092 I Bunk.~ hollse~ "... z o ::s.,' SURFACE PLAN OF GEOLOGY P I '., --.1 m Q lfl Q Q (\J f'~1 100 ~ 0 r=-...; - E=i -:J.3. t--.! F=f

13 U') o ~ v Scale of feel H < t.l....,. C'") c;c 0 z 0 ~ U') 0 U') ~ FIgure 3 - G I! ological... o ~ D - d Dio9,omrnalic Ihi M,oel. limlle k. of nils...epo.l. 1/ POt~s. 0 I the bo( and C O oc(ompany. - ~:" : cr G Lf c: c: ('I u c;c 0 I

GEORGETOWN QUARTZ TEXTURES

GEORGETOWN QUARTZ TEXTURES NOV 2017 Ashley Cody, Harry Mustard, Gregg Morrison GEORGETOWN METALLOGENIC STUDY INTRODUCTION AND OBJECTIVES FUNDED BY GEOLOGICAL SURVEY OF QUEENSLAND REVITALISE EXPLORATION