Volcanica https://www.jvolcanica.org/ojs/index.php/volcanica <p><em>Volcanica</em>&nbsp;seeks to publish high-quality, rigorously peer reviewed research pertaining to volcanology and related disciplines, while eliminating submission fees and keeping content freely accessible.</p> Presses Universitaires de Strasbourg en-US Volcanica <div style="padding: 10px; border: 3px solid gray; margin: 0;"> <p><a href="http://creativecommons.org/licenses/by/4.0/" rel="license"><img style="border-width: 0;" src="https://i.creativecommons.org/l/by/4.0/88x31.png" alt="Creative Commons License"></a><br>This work is licensed under a <a href="http://creativecommons.org/licenses/by/4.0/" rel="license">Creative Commons Attribution 4.0 International License</a>. Submission of an original manuscript to <em>Volcanica&nbsp;</em>will be taken to mean that it represents original work <strong>not previously published</strong>, and <strong>not being considered for publication elsewhere</strong>.&nbsp;</p> </div> Unravelling intrusion-induced forced fold kinematics and ground deformation using 3D seismic reflection data https://www.jvolcanica.org/ojs/index.php/volcanica/article/view/2 <p>Sills emplaced at shallow-levels are commonly accommodated by overburden uplift, producing forced folds. We examine ancient forced folds developed above saucer-shaped sills using 3D seismic reflection data from the Canterbury Basin, offshore SE New Zealand. Seismic-stratigraphic relationships indicate sill emplacement occurred incrementally over ~31 Myr between the Oligocene (~35–32 Ma) and Early Pliocene (~5–4 Ma). Two folds display flat-topped geometries and amplitudes that decrease upwards, conforming to expected models of forced fold growth. Conversely, two folds display amplitudes that locally increase upwards, coincident with a transition from flat-topped to dome-shaped morphologies and an across-fold thickening of strata. We suggest these discrepancies between observed and expected forced fold geometry reflect uplift and subsidence cycles driven by sill inflation and deflation. Unravelling these forced fold kinematic histories shows complex intrusion geometries can produce relatively simple ground deformation patterns, with magma transgression corresponds to localisation of uplift.</p> Jennifer Reeves Craig Magee Christopher Aiden-Lee Jackson ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2018-03-07 2018-03-07 1 1 1 17 10.30909/vol.01.01.0117