About Us | Help Videos | Contact Us | Subscriptions
 

Abstract

 

This article in SSSAJ

  1. Vol. 53 No. 1, p. 158-164
     
    Received: Dec 18, 1987


    * Corresponding author(s):
 View
 Download
 Alerts
 Permissions
 Share

doi:10.2136/sssaj1989.03615995005300010030x

Silicification of Holocene Soils in Northern Monitor Valley, Nevada

  1. O. A. Chadwick ,
  2. D. M. Hendricks and
  3. W. D. Nettleton
  1. Jet Propulsion Lab., California Inst. of Technology, MS 183-501, 4800 Oak Grove Drive, Pasadena, CA 91109
    Dep. of Soil and Water Sciences, Univ. of Arizona, Tucson, AZ 85721
    USDA-SCS National Soil Survey Lab., Federal Bldg., Rm. 345, 100 Centennial Mall N., Lincoln, NE 68508

Abstract

Abstract

In Monitor Valley, Nevada, two Entisols and an Aridisol containing volcanic glass have silica cementation that is first manifest as microagglomerates and later as macroscopic (>2-mm) durinodes and weakly cemented s-matrix. The initial effect of silicification is cementation of silt and clay by opaline SiO2, producing silt- and sand-size microagglomerates that are one source of large −1.5 MPa H2O/clay values for the <2-mm soil fraction. In the illuvial zone, microagglomerates are nuclei for further silica cementation and eventual durinode formation. Volcanic glass is a major source of silica for cementation; the 0.05- to 0.10-mm sand fraction is commonly composed of >40% volcanic glass, of which 40 to 80% is partly weathered; greatest proportions of weathered glass occur at about the same depths as maximum pH. Laboratory measurements of water-soluble silica and 0.5 M NaOH extractable silica, as well as the −1.5 MPa H2O/clay ratio, provide indications of incipient silicification. These values are relatively large throughout the sola but reach maxima before decreasing with increasing depth. This pattern indicates that glass weathering and relatively short-distance silica illuviation influence these recent soils.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © . Soil Science Society of America