Giant clastic intrusions primed by silica diagenesis

R. J. Davies, Mads Huuse, P. Hirst, J. Cartwright, Y. Yang

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    37 Citations (Scopus)

    Abstract

    Postdepositional sediment mobilization is a common phenomenon that occurs over large areas of sedimentary basins, usually within mudstone-rich successions; however, defining the exact mechanism that initiates this process has proved elusive. Here we describe a number of large-scale elastic intrusions (injectites), 50 to > 300 m in height, hosted within fine-grained biosificeous upper Eocene to Pliocene strata in four sedimentary basins. Within these basins diagenetic conversion of opal A into opal CT (cristobalite and tridymite) causes a marked reduction in sediment porosity and the liberation of bound water, often at relatively shallow burial (< 0.5 km). We propose that this occurs over geologically short time periods over large expanses of sedimentary basins, causing rapid pore fluid expulsion and overpressure buildup within interbedded sands. The liberated fluids primed these sands, rendering them susceptible to remobilization. This mechanism should have broad applicability.

    Original languageEnglish
    Pages (from-to)917-920
    Number of pages3
    JournalGeology
    Volume34
    Issue number11
    DOIs
    Publication statusPublished - Nov 2006

    Keywords

    • injectites
    • pore fluid
    • opal A
    • opal CT
    • overpressure
    • SANDSTONE INTRUSIONS
    • SEDIMENTARY BASINS
    • OPAL-A
    • COMPACTION
    • MECHANISMS
    • MARGIN
    • ORIGIN
    • AREA

    Cite this

    Davies, R. J., Huuse, M., Hirst, P., Cartwright, J., & Yang, Y. (2006). Giant clastic intrusions primed by silica diagenesis. Geology, 34(11), 917-920. https://doi.org/10.1130/G22937A.1