Joshua K. Miller , Christian Haselwimmer, Anupma Prakash Geophysical - - PowerPoint PPT Presentation

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Joshua K. Miller , Christian Haselwimmer, Anupma Prakash Geophysical - - PowerPoint PPT Presentation

Feb 13, 2024 244 likes •456 views

INVESTIGATING LOW-TEMPERATURE HYDROTHERMAL ALTERATION IN DRILL CUTTINGS FROM PILGRIM HOT SPRINGS, ALASKA, USING A SUITE OF LOW COST ANALYTICAL TECHNIQUES Joshua K. Miller , Christian Haselwimmer, Anupma Prakash Geophysical Institute, University

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Joshua K. Miller, Christian Haselwimmer, Anupma Prakash Geophysical Institute, University of Alaska Fairbanks

INVESTIGATING LOW-TEMPERATURE HYDROTHERMAL ALTERATION IN DRILL CUTTINGS FROM PILGRIM HOT SPRINGS, ALASKA, USING A SUITE OF LOW COST ANALYTICAL TECHNIQUES

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Acknowledgements

Research funding provided by Department of Energy Geothermal Technologies Programme (CID: DE-EE0002846) and the Alaska Energy Authority Renewable Energy Fund Round III Project team headed by Gwen Holdmann (ACEP, Director), consultants William (Bill) Cumming and Dick Benoit, as well as many other organizations:

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Overview

  • Pilgrim Hot Springs Geothermal System

– Conceptual Model

  • Analytical Methods

– Reflectance Spectroscopy – Methylene Blue Titration – X-ray Diffraction

  • Summary of Results
  • Conclusions
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Pilgrim Hot Springs

  • 1.5 km2
  • 91°C at 12 m

depth

  • 26-28 MWthermal
  • 2.6-2.8 MWelectric

(Chittambakkam et al., 2013)

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Conceptual Model

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Reflectance Spectroscopy

  • Reflectance spectroscopy is the

interaction of light with a medium that absorbs specific wavelengths that produces characteristic spectrums.

(Ruitenbeek et al., 2005)

Montmorillonite USGS Reference Sample Absorption Reflection

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Reflectance Spectroscopy

  • 120 sediment

samples

  • 7 cm intervals
  • ver 15 m of core
  • Bandwidth

– R: 2145 nm – G: 2205 nm – B: 2235 nm PS-12-2 Hyperspectral Cube

(Calvin et al., 2010)

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Reflectance Spectroscopy

5 10 15 20 25 30 MgChlorite Muscovitic Illite Muscovite FeMgChlorite Siderite Kaolinite Montmorillonite

5 10 15 20 25 30

Hornblende Biotite Ankerite Siderite Calcite Muscovite Muscovitic Illite Montmorillonite MgChlorite Phlogopite FeMgChlorite

PS-12-2 Sediments PS-12-2 Core Micas Clays

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Methylene Blue Titration

  • Determining presence of smectite

clay

  • Conductive signature
  • 28 sediment and bedrock samples

for PS-12-2

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X-ray Diffraction

  • 4, 20 m vertically-spaced

samples

  • Reflectance Spectroscopy &

Methylene Blue results comparison

  • Oriented <2 µm clay

particles and saturated with ethylene glycol

  • (M)ontmorillonite, (I)llite,

(B)iotite, (K)aolinite detected

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Conclusions

  • Abundant montmorillonite, kaolinite, white

micas, and illite detected

  • Possible indicators of hydrothermal alteration

assemblages

  • Techniques applicable as quick, cheap

assessment of alteration in low-temperature geothermal systems

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Extra Slides

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S N W E

Temperate Modeling

S N W E

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Geologic Data

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Groundwater flow

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Biotite schist Pegmatitic dike Diabase dike Biotite schist/pegmatitic dike contact