Sample Sites in Cariaco Basin

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SULFUR PROXIES IN TYPE III BLACK SHALES Fe, Mn,
Co, Cu, Ni, Zn, Sc Pat WILDE Pangloss
Foundation, 1735 Highland Place Berkeley, CA
94709 pat.wilde.td.57_at_aya.yale.edu Mary S.
QUINBY-HUNT Lawrence Berkeley Laboratory
Berkeley, CA 94720 mshunt_at_sbcglobal.net
Timothy W. LYONS Department of Earth Sciences,
University of California-Riverside Riverside,
CA 92521-0423 timothy.lyons_at_ucr.edu
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Why Calculate Proxies for C, S, P etc.?

• Data enhancement for old data sets
• Provide for elements not analyzed
• Useful for assessing initial reservoir conditions
  disguised by diagenesis and elemental transfer
  through geologic time
• Data recovery when originals not available

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Black Shale Groupsgt 50,000 ppm Al, lt 4000 ppm
Ca
Group 1 Oxic Group 2 Mn- Soluble Group 3 Mn,Fe- Soluble Group 4 V-High
Mn gt 830 Mn lt 730 Mn lt 730 Mn lt 230
Fe gt 38500 Fe lt 37500 Fe lt 37500 Fe lt 37500
V lt 320 V lt 320 V lt 320 V gt 320
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Sulfur proxies using Fe, Ni, Co, and Cu

• Determined with 62 Type-III Black Shales1 from
• Modern Cariaco Basin2 and
• Devonian of New York3
• Proxies developed for ODP Cariaco site2 used to
  estimate unreported S for Cariaco Basin USGS core
  PL07-39C4 located about 50 km E
• Corresponding lithologic units and ages were
  compared.
• Estimated values internally agreed within a range
  of 0.4 Sulfur.

1.Quinby-Hunt and Wilde, 1991, 1996 2. Lyons et
al.., 2003 3. Werne et al., 2002 4. Piper and
Dean, 2002
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Sulfur proxies using Fe, Ni, Co, and Cu

• High correlation over 400 million years ?
  Sulfur-Metal relationships relatively fixed
  during deposition and early diagenesis.
• Additional sulfur proxies with Mn, Sc and Zn,
  found in Cariaco Basin, but could not be
  reproduced for the Devonian samples.

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Type III Black Shale ProxiesComposite 62 samples

• Pyrite Sulfur 0.000105(Fe ppm) - 1.67
• R square 0.92
• Pyrite Sulfur 0.0179(Ni ppm) 0.339
• R square 0.88
• Pyrite Sulfur 0.118(Co ppm) .0967
• R square 0.85
• Pyrite Sulfur 0.0172(Cu ppm) 0.877
• R square 0.68

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Cariaco Basin New York Oatka Fm
Fe
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Cariaco Basin New York Oakta Fm
Ni
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Cariaco Basin New York Oatka Fm
Co
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Cariaco Basin New York Oatka Fm
Cu
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Reverse correlation Spy vs Mn Cariaco Basin vs
NY Devonian
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Trends in Oxygen, CO2, Sulfate and Phosphate over
Time
After COPSE model (Bergman et al., p. 418 2004
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Evidence of Oceanic Ventilation??

• Middle Devonian Oatka Creek Formation
• Deposited during rise in atmospheric O2 and
  development of land plants
• Atmospheric CO2 is reduced by production of O2
  thereby lowering ?CO2 concentration in seawater
• Sulfate in seawater also increased

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Evidence of Oceanic Ventilation??

• Decrease of Mn with increased S suggests prior
  to mid-Devonian
• MnCO3 deposition under anoxic conditions
• Fe sulfide deposition under anoxic conditions
• Lowering of ?CO2 increased oxygenation in
  mid-Devonian seawater ?
• Destabilization of MnCO3 ? Mn

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Mn and Fe Redox Zones with Rhodochrosite
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Evidence of Oceanic Ventilation??

• Accordingly
• MnCO3 dissolved into Mn2 returned to the
  water column
• Thus Mn decreases as Pyritic S increases.
• Sulfate reduction continues with Fe present to
  form additional pyrite

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New York Oatka Fm - Devonian
As
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Cariaco Basin - Zones I II
Sc
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Cariaco Basin - Zones I II
Zn
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Sulfur proxies using Fe, Ni, Co, and Cu

• Determined with 51 Type-III Black Shales1 from
• Modern Cariaco Basin2 and
• Devonian of New York3
• Proxies developed for ODP Cariaco site2 used to
  estimate unreported S for Cariaco Basin USGS core
  PL07-39C4 located about 50 km E
• Estimated values internally agreed within a range
  of 0.4 Sulfur.

1.Quinby-Hunt and Wilde, 1991, 1996 2. Lyons et
al.., 2003 3. Werne et al., 2002 4. Piper and
Dean, 2002
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Sample Sites in Cariaco BasinODP Lyons et al.
(2003) PLO7 Piper and Dean (2002)
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Sulfur Proxy by MetalsCariaco Basin Comparisons
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Sulfur proxies using Fe, Ni, Co, and Cu

• Extrapolation of sulfur proxies using Mn, Sc, and
  Zn over long time spans should be used with
  caution.
• Variations among proxies with time might beused
  to track various sedimentary and mineralogical
  processes.
• More data sets of varying ages, but with similar
  lithologies and anoxic conditions, should be
  compared.

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• What does this all mean??
• Ray knew!!

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Siever Diagram
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• THANKS, RAY !!! For all the wonderful MEMORIES

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SULFUR PROXIES IN TYPE III BLACK SHALES Fe, Mn,
Co, Cu, Ni, Zn, Sc Pat WILDE Pangloss
Foundation, 1735 Highland Place Berkeley, CA
94709 pat.wilde.td.57_at_aya.yale.edu Mary S.
QUINBY-HUNT Lawrence Berkeley Laboratory
Berkeley, CA 94720 mshunt_at_sbcglobal.net
Timothy W. LYONS Department of Earth Sciences,
University of California-Riverside Riverside,
CA 92521-0423 timothy.lyons_at_ucr.edu
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References

• Piper, D. Z. and Dean, W. E. , 2002,
  Trace-Element Deposition in the Cariaco
  Basin,Venezuela Shelf, under Sulfate-Reducing
  Conditions. A History of the Local Hydrography
  and Global Climate, 20 Ka to the Present US
  Geological Survey Prof. Paper 670, 1-41.
• Quinby-Hunt. M. S. and P. Wilde, 1991, The
  provenance of low-calcic black shales Mineralium
  Deposita, v. 26, p. 113-121.
• Quinby-Hunt, M. S. and Wilde, P., 1996,
  Depositional environments of calcic marine black
  shales Economic Geology, vol. 91, p. 4-13.
• Werne, J. P., Sageman, B. B., Lyons, T. W. and
  Hollander, D. J., 2002, An integrated assessment
  of a "type euxinic" deposit Evidence for
  multiple controls on black shale deposition in
  the Middle Devonian Oatka Creek Formation
  American Journal of Science, v. 302, p. 110-143.