A History of Geothermal Energy Research and Development in the ...

More documents

Recommendations

Info

EXPLORATION Figure 17. Progressive formation of silica polymorphs resulting from catastrophic reservoir boiling. Photomicrographs (A-D) and scanning electron microscope (SEM) images (E, F) are from Karaha-Telaga Bodas. A) At the lowest temperatures, the silica was deposited as alternating layers of amorphous silica (amor) and chalcedony (chal). B) Chalcedony is the only silica polymorph present at intermediate temperatures (250°C chalcedony is overprinted by quartz (qtz). Traces of epidote (ep), actinolite (act), and pyrite (py) are present. E-F) SEM images of quartz after chalcedony. Calcite (cal) was deposited after quartz in E. 60 A History of Geothermal Energy Research and Development in the United States | Exploration
GEOLOGICAL TECHNIQUE DEVELOPMENT / 5 5.6 Duration and Age of Hydrothermal Activity The presence of young volcanic rocks (< 1 my in age) was found to be among the best diagnostic criteria for locating potential geothermal resources. From this, researchers inferred that geothermal activity typically spanned long time periods. 167 More recent studies, however, suggested that geothermal activity was frequently episodic and that individual pulses could be relatively short-lived. Sinter deposits at Roosevelt Hot Springs and Steamboat Hot Springs were dated. 168-169 Carbon-14 ages of organic material encapsulated in the deposits were much younger than volcanic rocks at the same locations. Dates obtained on the basal portions of two sinters at the Opal Mound at Roosevelt Hot Springs yielded ages of 1,630 ± 90 and 1,920 ± 160 y BP. Dating of a 15-meters (49-feet) thick sequence of sinter deposits at Steamboat Hot Springs suggested that activity began at approximately 11,493 ± 70 y BP. An important observation was that the transformation of amorphous silica to quartz may have occurred very rapidly, within a few thousand years, and that this transformation could not be used to estimate the age of hot spring activity. Other studies constrained the ages of geothermal activity in two volcanic systems— Tiwi, Philippines and Karaha-Telaga Bodas, Indonesia. 163/170 Argon 40/39 ( 40 Ar/ 39 Ar) spectrum dating of vein adularia from Tiwi, when combined with fluidinclusion temperatures, documented a complex thermal history that began with adularia deposition between approximately 314 and 279 ka. 170 Between 279 and 200 ka, temperatures of at least 300°C were reached intermittently in response to a short-term (e.g. 20,000 y) thermal pulse(s) or were maintained by slow cooling. A long period of quiescence lasting from 200 to 50 ka followed. The present system is no older than 10 to 50 ka. It is significant that fracture zones, which are permeable during the early phase of geothermal activity, also control fluid flow today. 14 C ages of altered lake beds in the volcanic-hosted system at Karaha-Telaga Bodas also documented recent thermal activity. In this case, hydrothermal and magmatic activity was found to be no older than approximately 5,910 ± 76 y. 163 Similarly, recent heating events were suggested by preliminary 40 Ar/ 39 Ar spectrum dating of rocks from Coso, indicating that the present temperatures may not have persisted for more than 10 ka. 171 In another instance, young thermal pulses at the Salton Sea were implied by zircons with uranium-thorium (U-Th) ages between 30 ± 13 and 9 ± 7 ka. 172 DOE scientists used geochemistry in the exploration stages of a geothermal program to estimate reservoir temperatures, locate permeable fault zones, trace fluid sources, and evaluate past fluid temperatures and salinities. Toward these goals, the trace-element, stable-isotope and noble-gas compositions of soils, rocks and fluids were analyzed. Changes in the thermal and geochemical conditions within reservoirs were monitored by integrating mineral distributions with microthermometric measurements on the fluid inclusions trapped within these minerals. A History of Geothermal Energy Research and Development in the United States | Exploration 61
Page 1 and 2:
GEOTHERMAL TECHNOLOGIES PROGRAM Exp
Page 3 and 4:
EXPLORATION This history of the U.S
Page 5 and 6:
EXPLORATION Table of Contents Prefa
Page 7 and 8:
EXPLORATION Figure 15. Conceptual m
Page 9 and 10:
EXPLORATION Preface In the 1970s, t
Page 11 and 12:
EXPLORATION Acknowledgements While
Page 13 and 14:
EXPLORATION Introduction This repor
Page 15 and 16:
EXPLORATION was vastly expanded, re
Page 17 and 18:
EXPLORATION Accomplishments and Imp
Page 19 and 20:
EXPLORATION Technical Area Accompli
Page 21 and 22: EXPLORATION Technical Area Accompli
Page 23 and 24: EXPLORATION Major Research Projects
Page 25 and 26: EARLY STUDIES / 1 1.0 Early Studies
Page 27 and 28: INDUSTRY COOPERATIVE EXPLORATION AN
Page 43 and 44: STATE COOPERATIVE PROGRAMS / 3 3.0
Page 45 and 46: STATE COOPERATIVE PROGRAMS / 3 comp
Page 47 and 48: DRILLING FLUIDS AND WELLBORE INTEGR
Page 61 and 62: GEOLOGICAL TECHNIQUE DEVELOPMENT /
Page 71: GEOLOGICAL TECHNIQUE DEVELOPMENT /
Page 75 and 76: GEOCHEMICAL TECHNIQUE ANALYSIS / 6
Page 81 and 82: GEOPHYSICAL TECHNIQUE DEVELOPMENT /
Page 99 and 100: EXPLORATION STRATEGIES / 8 8.0 Expl
Page 101 and 102: NATIONAL AND REGIONAL RESOURCE ASSE
Page 103 and 104: MAGMA ENERGY STUDIES / 10 10.0 Magm
Page 105 and 106: MAGMA ENERGY STUDIES / 10 travel fo
Page 107 and 108: EXPLORATION Conclusion At the begin
Page 109 and 110: EXPLORATION Appendix A: Budget hist
Page 111 and 112: EXPLORATION the funds are typically
Page 113 and 114: EXPLORATION Capital Equipment Baca
Page 115 and 116: EXPLORATION Abbreviations & Acronym
Page 117 and 118: EXPLORATION py Pyrite T Temperature
Page 119 and 120: EXPLORATION References Organized by
Page 121 and 122: EXPLORATION Budding, K.E. and Summe
Page 123 and 124:
EXPLORATION Trexler, D., Flynn, T.,
Page 125 and 126:
EXPLORATION Hulen, J.B., Kaspereit,
Page 127 and 128:
EXPLORATION Waibel, A.F., 1987, An
Page 129 and 130:
EXPLORATION Kennedy-Bowdoin, T., Si
Page 131 and 132:
EXPLORATION Geochemical Technique A
Page 133 and 134:
EXPLORATION Beall, J.J., Stark, M.A
Page 135 and 136:
EXPLORATION Glenn, W.E. and Hulen,
Page 137 and 138:
EXPLORATION Mauer, J., and Atwood,
Page 139 and 140:
EXPLORATION Shuey, R.T., Schellinge
Page 141 and 142:
EXPLORATION Wilt, M.J., and Goldste
Page 143 and 144:
EXPLORATION Numbered References 1.
Page 145 and 146:
EXPLORATION 42. P.M. Wright et al.
Page 147 and 148:
EXPLORATION 81. E.T. Dixon et al.
Page 149 and 150:
EXPLORATION 120. P.W. Kasameyer, L.
Page 151 and 152:
EXPLORATION 159. J.B. Hulen and S.J
Page 153 and 154:
EXPLORATION 199. P.M. Wright. “Se
Page 155 and 156:
EXPLORATION 241. J. Mauer and J.W.
Page 157 and 158:
EXPLORATION 286. J.H. Beyer. “Tel
Page 160:
EERE Information Center 1-877-EERE-
show all

A History of Geothermal Energy Research and Development in the ...

Create successful ePaper yourself

Delete template?

Save as template?