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    <title>UTas ePrints - Short Wavelength Infrared Spectral Characteristics of the HW Horizon: Implications for Exploration in the Myra Falls Volcanic-Hosted Massive Sulfide Camp, Vancouver Island, British Columbia, Canada</title>
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    <meta content="Jones, Sarah" name="eprints.creators_name" />
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<meta content="Short Wavelength Infrared Spectral Characteristics of the HW Horizon:
Implications for Exploration in the Myra Falls Volcanic-Hosted Massive Sulfide Camp, Vancouver Island, British Columbia, Canada" name="eprints.title" />
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<meta content="Short wavelength infrared (SWIR) spectrometry has been used to identify previously unmapped hydrothermal
alteration zones around volcanic-hosted massive sulfide (VHMS) orebodies at Myra Falls, Vancouver Island,
British Columbia. Hydrothermal alteration assemblages are uniformly dominated by fine-grained white
mica, with poor development of mineralogical zonation. SWIR spectrometry is an ideal exploration tool for
characterizing this fine-grained hydrothermal alteration. At Myra Falls, SWIR spectrometry has identified subtle
shifts in the wavelengths of the AlOH absorption feature of white mica, corresponding to compositional
changes in altered rhyolite distal and proximal to ore. AlOH absorption occurs at shorter wavelengths (<2,198
nm) and corresponds to lower Fe, Fe + Mg, and Si/Al and higher Na/(Na + K) in strongly altered samples proximal
to ore (slightly sodic muscovites). AlOH absorption occurs at longer wavelengths (>2,206 nm) and corresponds
to higher Fe, Fe + Mg, and Si/Al and lower Na/(Na + K) in samples distal to ore (nonsodic slightly
phengitic muscovites). White mica in siltstone within a meter of VHMS ore has higher Zn, V, Fe, and Mg contents
than white mica distal to these altered samples. Chlorite compositions, identified by SWIR, also show systematic
changes with intensity of alteration and distance from ore. The average wavelength of the FeOH absorption
feature for chlorite in rhyolitic samples proximal to ore is 2,241 nm (intermediate Mg chlorite),
whereas wavelengths in background samples average 2,247 nm (intermediate Fe chlorite). Similar changes are
observed in footwall and hanging-wall andesites, with samples near the Battle mine containing muscovite to
phengitic muscovite (average wavelength of the AlOH absorption feature of 2,200 nm) and Mg-rich chlorite
(average wavelength of the FeOH absorption feature of 2,245 nm) to regional andesite samples with phengitic
muscovite (average wavelengths of the AlOH absorption feature of 2,209 nm) and Fe-rich chlorite (average
wavelength of the FeOH absorption feature of 2,249 nm). In weakly altered rocks white mica compositions also
vary with host lithology. The AlOH absorption feature occurs at longer wavelengths in white mica in dacite and
andesite compared to adjacent rhyolitic rocks, suggesting that higher Fe and Mg in the host lithology affects
the composition of white mica.
Two zones of intense hydrothermal alteration above the Battle and HW orebodies have distinctive SWIR
spectral characteristics, with the AlOH and FeOH features occurring at shorter wavelengths (<2,197 and
<2,240 nm, respectively). Small anomalous zones of alteration were also identified in the Thelwood Valley area,
where minor mineralized zones are present. As broad zones of fine-grained white mica (sericite) alteration are
ubiquitous throughout the Myra Falls property, alteration proximal to ore cannot be identified simply by visual
logging of drill core. Alteration zonation may be determined by subtle shifts in white mica spectral characteristics.
This study indicates that SWIR analysis may be an effective field-based exploration tool for quantifying
the intensity of alteration associated with VHMS orebodies, and that trends in mineral compositions, even in
very fine grained rocks, can be used as mine-scale vectors to ore.
" name="eprints.abstract" />
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<meta content="Barrett, T.J., and Sherlock, R.L., 1996, Volcanic stratigraphy, lithogeochemistry,
and seafloor setting of the H-W massive sulfide deposit, Myra Falls,
Vancouver Island, British Columbia: Exploration and Mining Geology, v. 5,
p. 421–458.
Cathelineau, M., 1988, Cation site occupancy in chlorites and illites as a function
of termperature: Clay Minerals, v. 23, p. 471–485.
Cathelineau, M., and Izquierdo, G., 1988, Temperature-composition relationships
of authigenic micaceous minerals in the Los Azufres geothermal
system: Contributions to Mineral and Petrology, v. 100, p. 418–428.
Clark, R.N., Vance, S., and Green, R.O., 1998, Mineral mapping with imaging
spectroscopy, the Ray mine, AZ: Pasadena, California, Jet Propulsion
Laboratory Publication 97-21, p. 67–75.
Deer, W.A., Howie, R.A., and Zussman, J., 1996, An introduction to the rockforming
minerals, 2nd ed.: New York, NY, Addison Wesley Longman Ltd.,
696 p.
Eugster H.P., and Yoder, H.S., 1955, The join muscovite-paragonite: Washington,
Carnegie Institution Yearbook 54, p. 124–129.
Gabrielse, H., and Yorath, C.J., 1991, Tectonic synthesis: Geological Survey
of Canada, Geology of Canada, no. 4, v. G-2, p. 677–705.
Greenwood, H.J., Woodsworth, G.J., Read, P.B., Ghent, E.D., and Evenchick,
C.A., 1991, Metamorphism: Geological Survey of Canada, Geology of
Canada, no. 4, v. G-2, p. 533–570.
Guidotti, C.V., Sassi, F.P., and Blencoe, J.G., 1994, The effects of ferromagnesian
components on the paragonite-muscovite solvus: A semiquantitative
analysis based on chemical data for natural paragonite-muscovite pairs:
Journal of Metamorphic Geology, v. 12, p. 779–788.
Hannington, M.D., Galley, A.D., Herzig, P.M. and Petersen, S., 1998, Comparison
of the TAG Mound and stockwork complex with Cyprus-type massive
sulfide deposits: Proceedings of the Ocean Drilling Program, Scientific
Results, v. 158, p. 389–415.
Herrmann, W., Blake, M., Doyle, M., Huston, D., Kamprad, J., Merry, N.
and Pontual, S., 2001, Short wavelength infrared (SWIR) spectral analysis
of hydrothermal alteration zones associated with base metal sulfide deposits
at Rosebery and Western Tharsis, Tasmania, and Highway-Reward,
Queensland: ECONOMIC GEOLOGY, v. 96, p. 939–955.
Huston, D.L., Kamprad, J., and Brauhart, C., 1999, Definition of high-temperature
alteration zones with PIMA: An example from the Panorama VHMS district,
central Pilbara craton: AGSO Research Newsletter 30, p. 10–12.
Jones, S.A., 2002, Geology and geochemistry of caprocks at Myra Falls
VHMS camp, Vancouver Island, B.C., Canada: Unpublished Ph.D. thesis,
Hobart, CODES, University of Tasmania, 511 p.
Jones, S.A., and Berry, R., 2001, Recognition of early growth structures after
multiple deformation episodes at Myra Falls VHMS camp, Vancouver Island,
B.C., Canada [abs.]: Geological Society of Australia Special Publiction
64, p. 101–102.
Jones, S.A., Gemmell, J.B., Davidson, G.J., and Boliden-Westmin geological
staff, 2000, Geological and geochemical characteristics of siliceous “cap
rocks,” Myra Falls VHMS camp, Vancouver Island, B.C., Canada [abs.]:
Tasmania, University of Tasmania, Centre for Ore Deposit Research Special
Publication 3, p. 105–106.
Juras, S.J., 1987, Geology of the polymetallic volcanogenic Buttle Lake camp,
with emphasis on the Price hillside, Central Vancouver Island, British Columbia,
Canada: Unpublished Ph.D. thesis, Vancouver, BC, University of
British Columbia, 278 p.
Juras, S.G., and Pearson, C.A., 1990a, The Buttle Lake camp, Central Vancouver
Island, B.C: Geological Survey of Canada Open File 2167, p.
145–161.
——1990b, Mineral deposits of the southern Canadian Cordillera: Geological
Association of Canada-Mineral Association of Canada Joint Meeting,
Vancouver, BC, 1990, Field Trip Guidebook B2, p. 1–21.
Leistel, J.M., Marcoux, E., Thieblemont, D., Quesada C., Sanchez, A., Alomdovar,
G.R., Pascual, E., and Saez, R., 1998, The volcanic hosted massive sulfide
deposits of the Iberian Pyrite Belt: Mineralium Deposita, v. 33, p. 2–30.
Massey, N.W.D., 1992, Geology and mineral resources of the Duncan sheet,
Vancouver Island: Geological Survey of Canada Report 92B/13, 57 p.
McLeod, R.L., and Stanton, R.L., 1984, Phyllosilicates and associated minerals
in some Paleozoic stratiform sulfide deposits of southeastern Australia:
ECONOMIC GEOLOGY, v. 79, p. 1–21.
Merry, N.J., and Pontual, S., 1998, The spectral geologist, v. 1.0, User’s manual:
Kew, Victoria 3101, Australia, Ausspec International Pty. Ltd., 90 p.
Muller, J.E., 1980, The Paleozoic Sicker Group of Vancouver Island, British
Columbia: Geological Survey of Canada Paper 79-30, 22 p.
Pearson, C.A., 1993, Mining zinc-rich massive sulphide deposits on Vancouver
Island, British Columbia [abs.]: World Zinc ’93 International Symposium,
Hobart, Australia, Australasian Institute of Mining and Metallurgy,
Proceedings, v. 7, p. 75–84.
Pearson, C.A., Juras, S.J. and McKinley, S.D., 1997, Paleotopography and ore
zonation of the H-W and Battle Zn-Cu-Au-Ag VMS deposits, Myra Falls
camp, Vancouver Island, British Columbia, Canada: Society of Economic
Geologists Field Conference, Neves Corvo, Lisbon, Portugal, 67 p.
Plimer, I.R., and de Carvalho, D., 1982, The geochemistry of hydrothermal
alteration at the Salgadinho copper deposit, Portugal: Mineralium Deposita,
v. 17, p. 193–211.
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field manual: Kew, Victoria 3101, Australia, Ausspec International
Pty. Ltd., 169 p.
——1997b, G-Mex Vol. 7, Volcanic-hosted massive sulfide systems: Kew,
Victoria 3101, Australia, Ausspec International Pty. Ltd., 43 p.
Post, J.L., and Noble, P.L., 1993, The near-infrared combination band frequencies
of dioctohedral smectites, micas and illites: Clays and Clay Minerals,
v. 41, p. 639–644.
Robinson, M., Godwin, C.I., and Stanley, C.R., 1996, Geology, lithogeochemisty,
and alteration of the Battle volcanogenic massive sulfide zone,
Buttle Lake mining camp, Vancouver Island, British Columbia: ECONOMIC
GEOLOGY, v. 91, p. 527–548.
Sinclair, B.J., 2000, Geology and genesis of the Battle zone VHMS deposits,
Myra Falls district, British Columbia, Canada: Unpublished Ph.D. thesis,
Hobart, University of Tasmania, 321 p.
Sinclair, B.J., Berry, R.F., and Gemmell, J.B., 2000a, Mineralogy and textures
of the Battle zone massive sulfide lenses, Myra Falls district, British Columbia,
Canada [abs.]: Tasmania, University of Tasmania, Centre for Ore
Deposit Research Special Publication 3, p. 197–199.
Sinclair, B.J., Gemmell, J.B. and Berry, R.F., 2000b, Formation of the Battle
mine massive sulfide deposits, Myra Falls, VHMS district, Vancouver
Island, B.C., Canada [abs.]: Tasmania, University of Tasmania, Centre for
Ore Deposit Research Special Publication 3, p. 195–196.
Thompson, A.J.B., Hauff, P.L., Robitaille, A.J., 1999, Alteration mapping in
exploration: Application of short-wave infrared (SWIR) spectroscopy: Society
of Economic Geologists Newsletter 39, p. 1, 16–27.
Velde, B., 1965, Phengite micas: Synthesis, stability, and natural occurrence:
American Journal of Science, v. 263, p. 886–913.
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<meta content="Jones, Sarah and Herrmann, W. and Gemmell, J.B. (2005) Short Wavelength Infrared Spectral Characteristics of the HW Horizon: Implications for Exploration in the Myra Falls Volcanic-Hosted Massive Sulfide Camp, Vancouver Island, British Columbia, Canada. Economic Geology, 100 (2). pp. 273-294. ISSN 0361-0128" name="eprints.citation" />
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<meta content="Short wavelength infrared (SWIR) spectrometry has been used to identify previously unmapped hydrothermal
alteration zones around volcanic-hosted massive sulfide (VHMS) orebodies at Myra Falls, Vancouver Island,
British Columbia. Hydrothermal alteration assemblages are uniformly dominated by fine-grained white
mica, with poor development of mineralogical zonation. SWIR spectrometry is an ideal exploration tool for
characterizing this fine-grained hydrothermal alteration. At Myra Falls, SWIR spectrometry has identified subtle
shifts in the wavelengths of the AlOH absorption feature of white mica, corresponding to compositional
changes in altered rhyolite distal and proximal to ore. AlOH absorption occurs at shorter wavelengths (<2,198
nm) and corresponds to lower Fe, Fe + Mg, and Si/Al and higher Na/(Na + K) in strongly altered samples proximal
to ore (slightly sodic muscovites). AlOH absorption occurs at longer wavelengths (>2,206 nm) and corresponds
to higher Fe, Fe + Mg, and Si/Al and lower Na/(Na + K) in samples distal to ore (nonsodic slightly
phengitic muscovites). White mica in siltstone within a meter of VHMS ore has higher Zn, V, Fe, and Mg contents
than white mica distal to these altered samples. Chlorite compositions, identified by SWIR, also show systematic
changes with intensity of alteration and distance from ore. The average wavelength of the FeOH absorption
feature for chlorite in rhyolitic samples proximal to ore is 2,241 nm (intermediate Mg chlorite),
whereas wavelengths in background samples average 2,247 nm (intermediate Fe chlorite). Similar changes are
observed in footwall and hanging-wall andesites, with samples near the Battle mine containing muscovite to
phengitic muscovite (average wavelength of the AlOH absorption feature of 2,200 nm) and Mg-rich chlorite
(average wavelength of the FeOH absorption feature of 2,245 nm) to regional andesite samples with phengitic
muscovite (average wavelengths of the AlOH absorption feature of 2,209 nm) and Fe-rich chlorite (average
wavelength of the FeOH absorption feature of 2,249 nm). In weakly altered rocks white mica compositions also
vary with host lithology. The AlOH absorption feature occurs at longer wavelengths in white mica in dacite and
andesite compared to adjacent rhyolitic rocks, suggesting that higher Fe and Mg in the host lithology affects
the composition of white mica.
Two zones of intense hydrothermal alteration above the Battle and HW orebodies have distinctive SWIR
spectral characteristics, with the AlOH and FeOH features occurring at shorter wavelengths (<2,197 and
<2,240 nm, respectively). Small anomalous zones of alteration were also identified in the Thelwood Valley area,
where minor mineralized zones are present. As broad zones of fine-grained white mica (sericite) alteration are
ubiquitous throughout the Myra Falls property, alteration proximal to ore cannot be identified simply by visual
logging of drill core. Alteration zonation may be determined by subtle shifts in white mica spectral characteristics.
This study indicates that SWIR analysis may be an effective field-based exploration tool for quantifying
the intensity of alteration associated with VHMS orebodies, and that trends in mineral compositions, even in
very fine grained rocks, can be used as mine-scale vectors to ore.
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    <h1 class="ep_tm_pagetitle">Short Wavelength Infrared Spectral Characteristics of the HW Horizon: Implications for Exploration in the Myra Falls Volcanic-Hosted Massive Sulfide Camp, Vancouver Island, British Columbia, Canada</h1>
    <p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Jones, Sarah</span> and <span class="person_name">Herrmann, W.</span> and <span class="person_name">Gemmell, J.B.</span> (2005) <xhtml:em>Short Wavelength Infrared Spectral Characteristics of the HW Horizon: Implications for Exploration in the Myra Falls Volcanic-Hosted Massive Sulfide Camp, Vancouver Island, British Columbia, Canada.</xhtml:em> Economic Geology, 100 (2). pp. 273-294. ISSN 0361-0128</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/2013/1/Jones2C_Herrmann2C_Gemmell_ECON_GEOL_2005.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/2013/1/Jones2C_Herrmann2C_Gemmell_ECON_GEOL_2005.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />1175Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input accept-charset="utf-8" value="3098" name="docid" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.2113/100.2.273">http://dx.doi.org/10.2113/100.2.273</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Short wavelength infrared (SWIR) spectrometry has been used to identify previously unmapped hydrothermal&#13;
alteration zones around volcanic-hosted massive sulfide (VHMS) orebodies at Myra Falls, Vancouver Island,&#13;
British Columbia. Hydrothermal alteration assemblages are uniformly dominated by fine-grained white&#13;
mica, with poor development of mineralogical zonation. SWIR spectrometry is an ideal exploration tool for&#13;
characterizing this fine-grained hydrothermal alteration. At Myra Falls, SWIR spectrometry has identified subtle&#13;
shifts in the wavelengths of the AlOH absorption feature of white mica, corresponding to compositional&#13;
changes in altered rhyolite distal and proximal to ore. AlOH absorption occurs at shorter wavelengths (&lt;2,198&#13;
nm) and corresponds to lower Fe, Fe + Mg, and Si/Al and higher Na/(Na + K) in strongly altered samples proximal&#13;
to ore (slightly sodic muscovites). AlOH absorption occurs at longer wavelengths (&gt;2,206 nm) and corresponds&#13;
to higher Fe, Fe + Mg, and Si/Al and lower Na/(Na + K) in samples distal to ore (nonsodic slightly&#13;
phengitic muscovites). White mica in siltstone within a meter of VHMS ore has higher Zn, V, Fe, and Mg contents&#13;
than white mica distal to these altered samples. Chlorite compositions, identified by SWIR, also show systematic&#13;
changes with intensity of alteration and distance from ore. The average wavelength of the FeOH absorption&#13;
feature for chlorite in rhyolitic samples proximal to ore is 2,241 nm (intermediate Mg chlorite),&#13;
whereas wavelengths in background samples average 2,247 nm (intermediate Fe chlorite). Similar changes are&#13;
observed in footwall and hanging-wall andesites, with samples near the Battle mine containing muscovite to&#13;
phengitic muscovite (average wavelength of the AlOH absorption feature of 2,200 nm) and Mg-rich chlorite&#13;
(average wavelength of the FeOH absorption feature of 2,245 nm) to regional andesite samples with phengitic&#13;
muscovite (average wavelengths of the AlOH absorption feature of 2,209 nm) and Fe-rich chlorite (average&#13;
wavelength of the FeOH absorption feature of 2,249 nm). In weakly altered rocks white mica compositions also&#13;
vary with host lithology. The AlOH absorption feature occurs at longer wavelengths in white mica in dacite and&#13;
andesite compared to adjacent rhyolitic rocks, suggesting that higher Fe and Mg in the host lithology affects&#13;
the composition of white mica.&#13;
Two zones of intense hydrothermal alteration above the Battle and HW orebodies have distinctive SWIR&#13;
spectral characteristics, with the AlOH and FeOH features occurring at shorter wavelengths (&lt;2,197 and&#13;
&lt;2,240 nm, respectively). Small anomalous zones of alteration were also identified in the Thelwood Valley area,&#13;
where minor mineralized zones are present. As broad zones of fine-grained white mica (sericite) alteration are&#13;
ubiquitous throughout the Myra Falls property, alteration proximal to ore cannot be identified simply by visual&#13;
logging of drill core. Alteration zonation may be determined by subtle shifts in white mica spectral characteristics.&#13;
This study indicates that SWIR analysis may be an effective field-based exploration tool for quantifying&#13;
the intensity of alteration associated with VHMS orebodies, and that trends in mineral compositions, even in&#13;
very fine grained rocks, can be used as mine-scale vectors to ore.&#13;
</p></div><table style="margin-bottom: 1em" cellpadding="3" class="not_ep_block" border="0"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Additional Information:</th><td valign="top" class="ep_row">Copyright 2005, Society of Economic Geologists.</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">mineralogy, mineral chemistry, volcanic stratigraphy, seafloor mineral deposits, metallogenesis</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/260100.html">260000 Earth Sciences &gt; 260100 Geology</a></td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">2013</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Mrs Katrina Keep</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">08 Nov 2007 16:09</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">09 Jan 2008 02:30</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=2013;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&amp;eprintid=2013">item control page</a></p>
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