Abstract

The deepwater Cenozoic strata in the North Carnarvon Basin, Australia, represent an interval of interest for stratigraphic studies in passive margins settings of mixed siliciclastic-carbonate environments. We have explored the geomorphological characteristics of a mass-transport deposit (MTD) within the Trealla Limestone Formation to describe in detail the differences among the blocks. To characterize the individual geometry and structural configuration of the blocks within the MTD, we used geometric seismic attributes such as coherence, curvature, dip azimuth, and dip magnitude using horizon slices and vertical profiles. The evaluation finds two types of blocks: remnant and glide (or rafted) blocks. Remnant blocks are in situ and stratigraphically continuous fragments with the underlying strata. This type of block is frequently fault-bounded and displays low deformation evidence. Glide blocks are part of the transported material detached from a paleoslope. These blocks are deformed and occasionally appear as “floating” fragments embedded within a chaotic matrix in the MTD. Glide blocks are used as kinematic indicators of the direction of deposition of MTDs. We evaluate these elements in a modern continental analog that resembles a similar setting for a better understanding of the slide occurrence.

     
  • Geological feature:

    Glide blocks, North Carnarvon Basin, Australia

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  • Seismic appearance:

    Discrete angular blocks with internal reflectors

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  • Alternative interpretations:

    Differential dissolution in a mixed siliciclastic-carbonate environment

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  • Features with a similar appearance:

    Carbonate buildups, differential dissolution blocks

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  • Formation:

    Trealla Limestone Formation, North Carnarvon Basin

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  • Age:

    Early-Middle Miocene

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  • Location:

    Offshore Northwest Australia, North Carnarvon Basin

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  • Seismic data:

    Obtained from Western Australian Petroleum and Geothermal Information Management System, Draeck 3D seismic data set

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  • Analysis tools:

    Visualization software (Petrel 2019) and attribute performance software (AASPI 6.0)

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