Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-26T01:09:40.293Z Has data issue: false hasContentIssue false

Diagenetic Alteration of Silicic Ash in Searles Lake, California

Published online by Cambridge University Press:  02 April 2024

Richard L. Hay
Affiliation:
Department of Geology, University of Illinois, 1301 West Green Street, Urbana, Illinois 61801
Sandra G. Guldman
Affiliation:
Environmental Science Associates, 760 Harrison Street, San Francisco, California 94107
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Ash layers from Searles Lake, California, were sampled in core of drill hole KM-3, which penetrated 693 m of lacustrine sediment deposited in a playa-lake complex over the past 3.2 my. Lake water changed from moderately saline and slightly alkaline (pH ~7.5) to highly saline 2.04 my ago and to highly saline and alkaline (pH ~9.5) 1.28 my ago. As a result of brines flushing downward, the upper 291 m of sediment, spanning the past 1.28 my, contain highly saline, alkaline pore fluid. Silicic ash layers in contact with highly saline, alkaline pore fluid were first altered to phillipsite and meriinoite and then to K-feldspar and searlesite. The transformation of phillipsite and/or meriinoite to K-feldspar required more than 45,000 years and was largely completed in 140,000 years. Tephra layers in contact with moderately saline, slightly alkaline pore fluid vary from uncemented vitric ash containing minor smectite to bentonites in which glass is wholly altered to smectite, clinoptilolite, analcime, and opal. Layers with much fine tephra are more altered than the coarser, better-sorted layers. Alteration is attributed to hydrolysis in essentially a closed hydrologic system, in which the alteration of glass to smectite raised the pH, aSiO2, and (Na+ + K+)/H+ activity ratio to the level where clinoptilolite formed. Some diffusion and/ or fluid flow is, however, indicated by the loss of SiO2 during the alteration of ash layers to smectite and by anhydrite deposited during and after clinoptilolite in some tuffaceous sandstones.

Type
Research Article
Copyright
Copyright © 1987, The Clay Minerals Society

References

Boles, J. R., 1972 Composition, optical properties, cell dimensions, and thermal stability of some heulandite-group zeolites Amer. Mineral. 57 14631493.Google Scholar
Donahoe, R. J., Liou, J. G. and Guldman, S., 1984 Synthesis and characterization of zeolites in the system Na2O-K2O-Al2O3-SiO2-H2O Clays & Clay Minerals 32 433443.CrossRefGoogle Scholar
Friedman, I., Smith, G. I. and Matsuo, S., 1982 Economic implications of the deuterium anomaly in the brine and salts in Searles Lake, California Econ. Geol. 77 694702.CrossRefGoogle Scholar
Guldman, S. G., 1984 Silicate diagenesis in core KM-3 from Searles (dry) Lake, California Berkeley, California M.S. thesis, University of California.Google Scholar
Hay, R. L. (1966) Zeolites and zeolitic reactions in sedimentary rocks: Geol. Soc. Amer. Spec. Paper 85, 130 pp.Google Scholar
Hay, R. L., 1970 Silicate reactions in three lithofacies of a semiarid basin, Olduvai Gorge, Tanzania Mineral. Soc. Amer. Spec. Pap. 3 237255.Google Scholar
Hay, R. L. and Moiola, R. J., 1963 Authigenic silicate minerals in Searles Lake, California Sedimentology 2 312332.CrossRefGoogle Scholar
Hay, R. L., Pexton, R. E., Teague, T. T. and Kyser, T. K., 1986 Spring-related carbonate rocks, Mg clays, and associated minerals in Pliocene deposits of the Amargosa Desert, Nevada and California Geol. Soc. Amer. Bull. 97 14881503.2.0.CO;2>CrossRefGoogle Scholar
Hein, J. R. and Scholl, D. W., 1978 Diagenesis and distribution of late Cenozoic volcanic sediment in the southern Bering Sea Geol. Soc. Amer. Bull. 89 197210.2.0.CO;2>CrossRefGoogle Scholar
Izett, G. A., 1981 Volcanic ash beds: Recorders of upper Cenozoic silicic pyroclastic volcanism in the western United States J. Geophys. Res. 86 1020010222.CrossRefGoogle Scholar
Khoury, H. N. and Eberl, D. D., 1981 Montmorillonite from the Amargosa Desert, southern Nevada, U.S.A. Neues Jb. Mineral. Abh. 141 134141.Google Scholar
Liddicoat, J. C., Opdyke, N. D. and Smith, G. I., 1980 Palaeomagnetic polarity in a 930 m core from Searles Valley, California Nature 286 2225.CrossRefGoogle Scholar
Perrier, R. and Quiblier, J., 1974 Thickness changes in sediment layers during compaction history; methods for quantitative evaluation Amer. Assoc. Petrol. Geol. Bull. 58 507520.Google Scholar
Sheppard, R. A. and Gude, A. J. 3rd (1968) Distribution and genesis of authigenic silicate minerals in tuffs of Pleistocene Lake Tecopa, Inyo County, California: U.S. Geol. Surv. Prof. Pap. 597, 38 pp.Google Scholar
Sheppard, R. A. and Gude, A. J. 3rd (1969) Diagenesis of tuffs in the Barstow Formation, Mud Hills, San Bernardino County, California: U.S. Geol. Surv. Prof. Pap. 634, 35 pp.Google Scholar
Siever, R., Beck, K. C. and Berner, R. A., 1965 Composition of interstitial waters of modern sediments J. Geol. 73 3973.CrossRefGoogle Scholar
Smith, G. I., 1976 Origin of lithium and other components in the Searles Lake evaporites, California U.S. Geol. Surv. Prof. Pap. 1005 92103.Google Scholar
Smith, G. I. (1979) Subsurface stratigraphy and geochemistry of Searles Lake late Quaternary evaporites, Searles Lake, California: U.S. Geol. Surv. Prof. Pap. 1043, 130 pp.Google Scholar
Smith, G. I., 1984 Paleohydrologic regimes in the southwestern Great Basin, 0–3.2 my ago, compared with other long records of “global” climate Quat. Res. 22 117.CrossRefGoogle Scholar
Smith, G. I., Barczak, V. J., Moulton, G. F. and Liddicoat, J. C. (1983) Core KM-3, a surface-to-bedrock record of late Cenozoic sedimentation in Searles Valley, California: U.S. Geol. Surv. Prof. Pap. 1256, 24 pp.Google Scholar
Surdam, R. C. and Mumpton, F. A., 1977 Zeolites in closed hydrologic systems Mineralogy and Geology of Natural Zeolites Washington, D.C. Reviews in Mineralogy 4, Mineralogical Society of America 6579.CrossRefGoogle Scholar