Abstract
A combined petrographic/X-ray/electron microprobe and energy dispersive system investigation of sandstone cuttings from borehole Elmore # 1 near the center of the Salton Sea Geothermal Field has revealed numerous regular variations in the composition, texture, mineralogy and proportions of the authigenic layer silicate minerals in the temperature interval 185° C (411.5 m depth) to 361° C (2,169 m). At temperatures near 190° C, dolomite/ankerite+calcite-bearing sandstones contain an illite/mixed layer phase with 10% expandable layers (dolomite/ankerite zone). In shale, the percentage of expandable layers in the mixed layer phase changes from 10–15% at 185° C to 5% at 210° C (494 m). In the interval 250° C (620 m) to 325° C (1,135 m), the calcite+pyrite+epidote-bearing sandstones contain a layer silicate assemblage of chlorite and illite (chlorite-calcite zone). In the shallower portions of this metamorphic zone, the illite contains 0–5% expandable layers, while at depths greater than 725 m (275° C) it is completely free of expandable layers. On increasing temperature, the white mica shows regular decreases in SiIV, Mg and Fe, and increase in AlIV, AlVI, and interlayer occupancy, as it changes gradually from fine-grained illite (=textural sericite) to coarse-grained recrystallized phengitic white mica. In the same interval, chlorite shows decreases in AlVI and octahedral vacancies and an increase in total Mg+Fe. The sandstones range from relatively unmodified detrital-textured rocks with porosities up to 20% and high contents of illite near 250° C to relatively dense hornfelsic-textured rocks with trace amounts of chlorite and phengite and porosities near 5% at 325° C. Numerous complex reactions among detrital (allogenic) biotite, chlorite, and muscovite, and authigenic illite and chlorite, occur in the chlorite-calcite zone.
Biotite appears, and calcite disappears, at a temperature near 325° C and a depth of 1,135m. The biotite zone so produced persists to 360° C in sandstone, at which temperature orthoclase disappears and andradite garnet appears at a depth near 2,155 m. Throughout the biotite zone and into the garnet zone, the biotite undergoes compositional changes that are very similar to those observed in illite/phengite in the chlorite-calcite zone, including increases in interlayer occupancy, AlIV, AlVI, and Ti, and decreases in F−, SiIV, and Mg/Fet+Mg, on increasing temperature. Biotite thus changes from a siliceous, K-deficient biotite at the biotite isograd to a typical low-grade metamorphic biotite at temperatures near 360° C. Minor amounts of talc appear with biotite at the biotite isograd in sandstone, while actinolite appears in both sandstone and shale at temperatures near 340° C (1,325 m). Chlorite completely disappears from sandstone at temperatures of approximately 350° C (1,500 m), and diminishes abruptly in amount in the more chloritic shales at the same depth.
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References
Albee AL, Beaty DW, Chodos AA, Quick JE (1978) Quantitative analysis of petrographic properties and of mineral compositions with a computer-controlled energy-dispersive system. Proc 8th Int Conf on X-ray optics and microanalysis Boston, Mass
Biehler S (1964) Geophysical study of the Salton Trough of Southern California. Ph D thesis, California Institute of Technology, Pasadena, 139 pp
Binns RA (1969) Ferromagnesian minerals in high-grade metamorphic rocks. Geol Soc Aust, Special Publ 2:323–332
Black PM (1975) Mineralogy of New Caledonia metamorphic rocks IV: Sheet silicates from the Ouegoa District. Contrib Mineral Petrol 49:269–284
Boles JR, Franks SG (1979) Clay diagenesis in Wilcox sandstones of southwest Texas: Implications of smectite diagenesis on sandstone cementation. J Sed Petrol 49:55–70
Brown EH (1967) The greenschist facies in part of eastern Otago, New Zealand. Contrib Mineral Petrol 14:259–292
Burst JF (1969) Diagenesis of Gulf Coast clayey sediments and its possible relation to petroleum migration. Am Assoc Petrol Geol Bull 53:73–93
Butler BCM (1967) Chemical study of minerals from the Moine Schists of the Ardnamurchen area, Argyllshire, Scotland. J Petrol 8:233–267
Chinner GA (1960) Pelitic gneisses with varying ferrous/ferric ratios from Glen Clova, Angus, Scotland. J Petrol 1:178–217
Cooper AF (1972) Progressive metamorphism of metabasic rocks from the Haast Schist Group of Southern New Zealand. J Petrol 13:457–492
Deer WA, Howie RA, Zussman J (1962) Rock Forming Minerals: Vol 3. Sheet Silicates: Longmans, Green & Co, London
Elders WA (1979) The geological background of the geothermal fields of the Salton Trough. In: Elders WA (ed) Geology and Geothermies of the Salton Trough. Geol Soc Am, Guidebook No 7, San Diego, California, p 1–19
Elders WA, Rex RW, Meidev T, Robinson PT, Biehler S (1972) Crustal spreading in Southern California. Science 178:15–24
Elders WA, Biehler S (1975) Gulf of California rift system and its implication for the tectonics of western North America. Geology 3:85–87
Engel AEJ, Engel CG (1960) Progressive metamorphism and granitization of the major paragneiss, NW Adirondack Mountains, New York. Geol Soc Am Bull 71:1–58
Ernst WG (1963) Significance of phengitic micas from low-grade schists. Am Mineral 48:1357–1373
Foster MD (1960) Interpretation of the composition of trioctrahedral micas. US Geol Surv Prof Pap 354-B:11–49
Foster MD (1962) Interpretation of the composition and a classification of the chlorites. US Geol Surv Prof Pap 414-A:1–33
Foster MD (1963) Interpretation of the composition of vermiculites and hydrobiotites. Clays Clay Miner 10:70–89
Freckman JT (1978) Fluid inclusion and oxygen isotope geothermometry of rock samples from Sinclair # 4 and Elmore # 1 boreholes, Salton Sea Geothermal Field, Imperial Valley, California, USA. Inst Geophys Planetary Phys, Univ of Calif, Riverside: Rep 78/5, 66 pp
Frey N, Hunziker JC, Roggwiller P, Schindler C (1973) Progressive Niedriggradige Metamorphose glaukonitführender Horizonte in den Helvetischen Alpen der Ostschweiz (Ger). Contrib Mineral Petrol 39:185–218
Fuis C, Schnapp M (1977) The Nov.–Dec., 1976, earthquake swarms in northern Imperial Valley, California (abstr). EOS Trans Am Geophys Union 58:1188
Gilpin BE (1977) A microearthquake study of the Salton Sea Geothermal Area, Imperial Valley, Calif. Inst Geophys Planetary Phys, Univ of Calif, Riverside: Rep 77/10 65 pp
Guidotti CV, Sassi FP (1976) Muscovite as a petrogenetic indicator mineral in pelitic schists. Neues Jahrb Mineral, Abh 127:97–142
Hayama Y (1959) Some considerations on the color of biotite and its relation to nietamorphism. J Geol Soc Japan 65:21–37
Helgeson HC (1968) Geologic and thermodynamic characteristics of the Salton Sea Geothermal System. Am J Sci 266:129–166
Hoagland James R, McDowell SD (1978) Metamorphic zonation in the Cerro Prieto Geothermal Reservoir, Baja, California, Mexico. Geol Soc Am Abstr with Progr 10 (7), p 422
Hower J, Eslinger EV, Hower ME, Perry EA (1976) Mechanism of burial metamorphism of argillaceous sediment: 1. Mineralogical and chemical evidence. Geol Soc Am Bull 87:725–737
Hower J, Mowatt TC (1966) The mineralogy of illites and mixed-layer illite/montmorillonites. Am Mineral 51:825–854
Jacobs DC, Parry WT (1976) A comparison of the geochemistry of biotite from some Basin and Range stocks. Econ Geol 71:1029–1035
Johnson CE (1979) Seismotectonics of the Imperial Valley of Southern California; Part II of Ph D Thesis, Cal Tech
Johnson PD (1978) Use of automated X-ray diffraction analysis in studies of natural hydrothermal systems. In: Advances in X-ray Analysis, Vol 21. Plenum Press, NY, pp 267–274
Kendall C (1976) Petrology and stable isotope geochemistry of three wells in the Buttes area of the Salton Sea Geothermal Field, Imperial Valley, California: MS Thesis, University of California, Riverside, IGPP Rep No 76/17, 211 pp
Lambert RSTJ (1959) The mineralogy and metamorphism of the Moine Schists of the Moran and Knoydant Districts of Invernes-shire. Trans R Soc Edinburgh 63 (3), 553–588
Lee T, Cohen LH (1979) Onshore and offshore measurements of temperature gradients in the Salton Sea geothermal area, California. Geophysics 44:206–215
Mather JD (1970) The biotite isograd and the lower greenschist facies in the Dalradian rocks of Scotland. J Petrol 11:254–276
McDowell SD, Elders WA (1978) Distribution and chemistry of layer-silicate minerals in the Salton Sea Geothermal Field, California. Geol Soc Am Abstr with Progr 10 (7), p 452
McDowell SD, Elders WA (1979) Geothermal metamorphism of sandstone in the Salton Sea Geothermal System. In: Elders WA (ed) Geology and Geothermics of the Salton Trough. Geol Soc Am Guidebook No 7, San Diego, Calif, p 70–76
McDowell SD, Elders WA (1981) Allogenic layer silicate minerals in borehole Elmore 1, Salton Sea Geothermal Field, California, USA
McDowell SD, McCurry MO (1977) Active metamorphism in the Salton Sea Geothermal Field, California. Geol Soc Am Abstr with Progr 9 (7), p 1088
McNamara M (1965) The lower greenschist facies in the Scottish Highlands. Geol Foeren Stockholm Foerhandl 87:347–389
Miyashiro A (1958) Regional metamorphism of the Gosaisyo-Takanuki district in the central Abukuma Plateau. J Fac Sci Tokyo Univ, Sec II, 11:219–272
Muffler LPJ, Doe B (1968) Composition and mean age of detritus of the Colorado River in the Salton Trough, southeastern California. J Sediment Petrol 38:384–399
Muffler LPJ, White DE (1969) Active metamorphism of Upper Cenozoic sediments in the Salton Sea Geothermal Field and the Salton Trough, southeastern California. Geol Soc Am Bull 80:157–182
Oki Y (1961) Biotites in metamorphic rocks. Jpn J Geol Geogr 32:497–506
Olson ER (1977) Water-rock ratios and fluid mixing in the Salton Sea Geothermal Field. Geol Soc Am Abstr with Progr 9 (7), p 119
Palmer TD (1975) Characteristics of geothermal wells located in the Salton Sea Geothermal Field, Imperial Valley, California: University of California Lawrence Livermore Lab Report UCR-51976
Perry EA, Hower J (1970) Burial diagenesis in Gulf Coast pelitic sediments. Clays Clay Miner 18:165–178
Ramsay CR (1973) Controls of biotite zone mineral chemistry in Archaean meta-sediments near Yellowknife, Northwest Territories, Canada. J Petrol 14:467–488
Randall W (1974) An analysis of the subsurface structure and stratigraphy of the Salton Sea Geothermal Anomaly, Imperial County, California. Ph D thesis, University of California, Riverside
Rao TR (1977) Distribution of elements between coexisting phengite and chlorite from the greenschist facies of the Tennant Creek area, Central Australia. Lithos 10:103–112
Reynolds RC, Hower J (1970) The nature of interlayering in mixedlayer illite-montmorillonites. Clays Clay Miner 18:25–36
Spry A (1969) Metamorphic Textures. Pergamon Press, New York
Robinson PT, Elders WA, Muffler LPJ (1976) Quaternary volcanism in the Salton Sea Geothermal Field, Imperial Valley, California. Geol Soc Am Bull 87:347–360
Van de Kamp PC (1973) Holocene continental sedimentation in the Salton Basin, California: A reconnaisance. Geol Soc Am Bull 84:827–848
Velde B (1977a) Clays and Clay Minerals in Natural and Synthetic Systems: Developments in Sedimentology 21. Elsevier Sci Publ Co, Amsterdam
Velde B (1977b) A proposed phase diagram for illite, expanding chlorite, corrensite and illite-mont. mixed layered minerals. Clays Clay Miner 25:264–270
Velde B (1978) High temperature or metamorphic vermiculites. Contrib Mineral Petrol 66:319–323
Velde B, Rumble D (1977) Alumina content of chlorite in muscovite-bearing assemblages. Carnegie Inst Washington, Yearb 76:621–622
Waggoner JL (1977) Stratigraphy and sedimentation of the Pleistocene, Brawley and Borrego Formation in the San Felipe Hills area, Imperial Valley, California. Inst Geophys Planetary Phys, Univ Calif, Riverside: Rep 77/24
Weaver CE, Beck KC (1971) Clay-water diagenesis during burial: How mud becomes gneiss. Geol Soc Am, Spec Pap 134
Weaver CE, Pollard LD (1973) The chemistry of clay minerals: Developments in Sedimentology 15. Elsevier Sci Publ Co, Amsterdam
Zakrutkin VV, Grigorenko MV (1968) Titanium and alkalies in biotite in metamorphic facies. Dokl Ross Akad Nauk 178:124–127
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McDowell, S.D., Elders, W.A. Authigenic layer silicate minerals in borehole Elmore 1, Salton Sea Geothermal Field, California, USA. Contr. Mineral. and Petrol. 74, 293–310 (1980). https://doi.org/10.1007/BF00371699
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DOI: https://doi.org/10.1007/BF00371699