The role of mass transport deposits contributing to fluid escape: Neogene outcrop and seismic examples from north Tarana
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TECHNICAL PAPER
The role of mass transport deposits contributing to fluid escape: Neogene outcrop and seismic examples from north Taranaki, New Zealand G. H. Browne 1
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S. Bull 1
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M. J. Arnot 1
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A. F. Boyes 1 & P. R. King 1 & K. Helle 2
Received: 10 July 2019 / Accepted: 6 February 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Many sedimentary structures are the manifestation of fluid escape in sedimentary basins. This paper examines outcrop and seismic examples in upper Miocene deep-water sandstones and siltstones of north Taranaki, New Zealand. In outcrop examples of fluid escape features comprise discordant bodies within otherwise uniformly bedded surrounding stratigraphy, features characterized by steep sided, over-hanging, vertical or near-vertical margins, infilled with an assortment of poorly sorted or chaotically arranged sandstone and siltstone. Typically, these features are several metres wide and up to 20 m high in outcrop and always occur stratigraphically below a mass transport deposit (MTD). Examples of similar features from nearby 2D and 3D seismic reflection data consist of localized vertical to sub-vertical zones of disrupted reflectivity and are as much as 300 m in height and 10’s–100’s of metres in width. The structures occur in close association with the basal slide planes of seismic-scale MTDs. The close association of fluid escape structures with MTDs suggests that these features formed by the sudden loading of the sedimentary succession by the emplacement of several metre-thick overlying MTDs. We suggest recurring phases whereby the emplacement of MTDs triggered fluid escape within underlying strata and, in turn, the fluid escape contributed to further instability with potential for mobilization and transport of subsequent MTDs in a dynamic deep-water setting.
Introduction Fluid escape features are manifest in various forms in the geological record and exhibit a range of sedimentary and stratigraphic styles in seismic and outcrop. These include mud and sand volcanoes formed at the contemporaneous sea floor (Clari et al. 2004; Delisle 2004), chimneys or vertical pipe conduits (Løseth et al. 2009; Ilg et al. 2012; Cartwright and Santamarina 2015; Singh et al. 2016; Bertoni et al. 2018),
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00367-020-00641-z) contains supplementary material, which is available to authorized users. * G. H. Browne [email protected] * S. Bull [email protected] 1
GNS Science, 1 Fairway Drive, Lower Hutt 5018, New Zealand
2
Aker BP ASA, PO Box 65, NO-1324 Lysaker, Norway
pockmarks (Hovland et al. 1987; Agirrezabala et al. 2013; Chenrai and Huuse 2017) and concretions representing fluid flow conduits (Orpin 1997; Nyman et al. 2010; Nyman and Nelson 2011; Nelson et al. 2019). Sometimes these features may be genetically linked such as pipes and chimney structures with mud volcanoes developed where these features subcrop on the sea floor (Cartwright and Santamarina 2015). The explana
