Structure and
Sequence Stratigraphy of an Offshore Trench-Slope Basin—Comparison
with a Field Analogue, Hikurangi Subduction
Margin, New Zealand
Julien, Bailleul1, Chanier Frank1, Gorini
Christian1, Mahieux Geoffroy2,
Robin Cécile3, Ferriere Jacky1 (1)
UMR CNRS 8110 Lille University, Lille,
France (2) UMR CNRS 8110 UPJV University, Amiens, France (3) Rennes University, Rennes, France
The initiation and evolution of trench-slope basins on subduction wedges are strongly related to subduction processes. These narrow elongated basins form on
the lower trench slope, their edges consisting of structurally controlled
linear bathymetric highs. In this particular setting, sedimentary processes
may be controlled by both tectonics and sea-level changes. Thus, the study of
the sedimentary record can provide more accurate evaluation of the spatial and
temporal contribution of tectonic activity on the development and stratigraphic evolution of trench-slope basins.
This study is
based on a detailed stratigraphic analysis of the Titihaoa basin (Hikurangi subduction margin), offshore east coast of North Island, New Zealand. Compilation of seismic
stratigraphic and wireline
log (gamma ray and sonic) data, combined with lithostratigraphic
and biostratigraphic data obtained from well
Titihaoa-1, allows to characterize major unconformities within the sedimentary
infill of the lower trench slope. We interpret most of these unconformities in
terms of sequence stratigraphy. On the bases of
comparison with our results with onshore analogues, we propose a stratigraphic and structural conceptual model for
trench-slope basin development taking into account 1) our geophysical study of
the Titihaoa basin which permits to precise the role
of deformation processes on the basin geometry and on sequence development and organisation, and 2) the analysis of the onshore Akitio basin which provides accurate descriptions and
interpretations of turbidites facies
and related deep-sea deposits with a focus on the evolution of sedimentary
systems in response to changes in style and/or amplitude of tectonic activity.
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