Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(exploration vectors). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters

1. Hamisi, Jonathan. Defining The Geochemical Footprint For Gold Mineralisation Around Birthday Reef.Reefton Goldfield, New Zealand.

Degree: Geological Sciences, 2016, Stockholm University

Abstract Orogenic gold deposits from the Reefton goldfield in New Zealand hosted in Ordovician metasediments of the Greenland group have produce 67 tons of gold before 1951. The Blackwater mine in Waiuta account for about 1/3 of the gold production at Reefton prior 1951. The ore system at Blackwater consist of NE trending steeply dipping gold-bearing quartz veins (Birthday reef) occurring in faulted, sheared and folded alternating sequence of sandstone-mudstone metamorphosed to low greenschist facies and hydrothermally altered proximal to distal from the quartz vein. Host rock and ore forming fluids interaction resulted in a systematic change in the mineralogy and geochemistry of the wallrock developing a distinctive footprint of the ore system. The mineral assemblage subsequent to hydrothermal alteration is formed by quartz veining, chlorite, carbonates (minor calcite-dolomite-ankerite-siderite), albite, K-Mica and composite quartz-carbonate veining, carbonates spotting, pyrite, arsenopyrite, chalcopyrite, cobaltite, galena and in a lesser extent ullmannite, gersdorffite, pentlandite, millerite and sphalerite. Mass balance calculation based on geochemical data obtained by ultra-low detection analysis with a detection limit in part per trillion of Au, As and Sb provide new insight in the geochemical footprint of the ore system at Blackwater. A clear zone of roughly 40 meters (20 meters above and below the birthday reef) is enriched in Au, As and Sb up to respectively 6806%, 605% and 891% compared to the un-mineralised protolith. Furthermore, mass changes in K2O and Na2O indicate a consistent decrease in Na and increase in K in the vicinity of the Birthday reef reflecting the replacement of albite by K-mica. This is corroborated by pattern of alkali alteration index Na/Al for albite and 3K/Al for K-Mica showing similar trend. Carbonation and de/-hydration index also exhibits peaks in samples adjacent to the Birthday reef, though carbonation index is also influenced by carbonates content in the protolith or late carbonation that may not related to gold mineralisation. Using the indicators above-mentioned it is possible to define the mineralogical and geochemical “footprint” for the ore system in the host rock allowing to use this footprint as a tool for mineral exploration for orogenic gold deposits similar to Blackwater. Given that the geochemical footprint of orogenic gold deposit such as Blackwater is significantly wider than the economically viable part of the deposit defining the footprint of the ore system offers the potential for vectoring from sub-economic mineralisation towards higher-grade ore that is economically viable.

Subjects/Keywords: Orogenic gold; hydrothermal alteration; Reefton; mass changes; geochemical footprint; vectors; exploration; Blackwater

vectors, exploration, Blackwater 5 1. Introduction Orogenic gold deposits are a major source… …mineral exploration for orogenic gold deposits similar to Blackwater. Given that the geochemical… …Better understanding of the ore-forming systems is critical for more successful exploration and… …system and at the same time a practical tool for exploration is to define the geochemical and… …that is targeted in gold exploration at regional or deposit scale. The geochemical footprint… 

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hamisi, J. (2016). Defining The Geochemical Footprint For Gold Mineralisation Around Birthday Reef.Reefton Goldfield, New Zealand. (Thesis). Stockholm University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-132115

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Hamisi, Jonathan. “Defining The Geochemical Footprint For Gold Mineralisation Around Birthday Reef.Reefton Goldfield, New Zealand.” 2016. Thesis, Stockholm University. Accessed August 22, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-132115.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Hamisi, Jonathan. “Defining The Geochemical Footprint For Gold Mineralisation Around Birthday Reef.Reefton Goldfield, New Zealand.” 2016. Web. 22 Aug 2019.

Vancouver:

Hamisi J. Defining The Geochemical Footprint For Gold Mineralisation Around Birthday Reef.Reefton Goldfield, New Zealand. [Internet] [Thesis]. Stockholm University; 2016. [cited 2019 Aug 22]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-132115.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hamisi J. Defining The Geochemical Footprint For Gold Mineralisation Around Birthday Reef.Reefton Goldfield, New Zealand. [Thesis]. Stockholm University; 2016. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-132115

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Colorado School of Mines

2. Hanneman, Harry. Mineralogy and geochemistry of carbonaceous mudstone as a vector to ore : a case study at the Lagunas Norte high-sulfidation gold deposit, Peru.

Degree: MS(M.S.), Geology and Geological Engineering, 2007, Colorado School of Mines

The Lagunas Norte Au deposit in the Alto Chicama district of Peru is a ~14 Moz high-sulfidation epithermal deposit that is hosted by an atypical host-rock succession for this deposit type. Approximately 80% of the ore body is contained in the Lower Cretaceous Chimu Formation, which is composed of quartz arenite with interbedded carbonaceous mudstone, siltstone, and coal seams. The remainder of the ore is hosted by the Miocene volcanic rocks of the Calipuy Group, forming an irregular and thin veneer on the deformed sedimentary rocks of the basement. The host rock succession of the Lagunas Norte deposit has been affected by widespread hydrothermal alteration. The alteration is cryptic within most of sedimentary rocks as the quartz arenite was largely inert to alteration by the strongly acidic fluids. Vuggy textures associated with residual quartz alteration can only be recognized in the overlying Miocene volcanic rocks. However, the present study shows that mudstone of the Chimu Formation records acid-type alteration due to its originally high clay mineral content. The mineralogy of the mudstone broadly changes from residual quartz to quartz-alunite-pyrophyllite-kaolinite/dickite to illite-smectite away from the deposit. Mineralogical changes are paralleled by notable variations in the whole-rock major and trace element composition of the mudstone, allowing the definition of a set of alteration vectors to ore. Textural evidence suggests that alteration of the host rocks at Lagunas Norte predated precious metal mineralization. Residual quartz formed during the early acidic alteration is overgrown by later euhedral quartz that is texturally associated with the ore minerals. Fluid inclusion data suggest that the euhedral quartz and associated ore minerals formed from a low-temperature, low-salinity liquid. This liquid infiltrated the previously altered host rock succession, forming the sulfide ore zones of the epithermal deposit. Subsequent supergene weathering resulted in deep oxidation of the ore body. Advisors/Committee Members: Monecke, Thomas (advisor), Hitzman, Murray Walter (committee member), Simmons, S. F. (Stuart Frank) (committee member).

Subjects/Keywords: Lagunas Norte; high-sulfidation; exploration vectors; siliciclastic host rocks; mudstone alteration; epithermal gold; Mudstone  – Peru; Mineralogy  – Peru; Geochemistry  – Peru; Sedimentology  – Peru; Hydrothermal alteration  – Peru; Metallogeny  – Peru; Geology  – Peru

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hanneman, H. (2007). Mineralogy and geochemistry of carbonaceous mudstone as a vector to ore : a case study at the Lagunas Norte high-sulfidation gold deposit, Peru. (Masters Thesis). Colorado School of Mines. Retrieved from http://hdl.handle.net/11124/358

Chicago Manual of Style (16th Edition):

Hanneman, Harry. “Mineralogy and geochemistry of carbonaceous mudstone as a vector to ore : a case study at the Lagunas Norte high-sulfidation gold deposit, Peru.” 2007. Masters Thesis, Colorado School of Mines. Accessed August 22, 2019. http://hdl.handle.net/11124/358.

MLA Handbook (7th Edition):

Hanneman, Harry. “Mineralogy and geochemistry of carbonaceous mudstone as a vector to ore : a case study at the Lagunas Norte high-sulfidation gold deposit, Peru.” 2007. Web. 22 Aug 2019.

Vancouver:

Hanneman H. Mineralogy and geochemistry of carbonaceous mudstone as a vector to ore : a case study at the Lagunas Norte high-sulfidation gold deposit, Peru. [Internet] [Masters thesis]. Colorado School of Mines; 2007. [cited 2019 Aug 22]. Available from: http://hdl.handle.net/11124/358.

Council of Science Editors:

Hanneman H. Mineralogy and geochemistry of carbonaceous mudstone as a vector to ore : a case study at the Lagunas Norte high-sulfidation gold deposit, Peru. [Masters Thesis]. Colorado School of Mines; 2007. Available from: http://hdl.handle.net/11124/358

.