ORIGINAL RESEARCH PAPER Impacts of sediment supply and local tectonics on clinoform distribution: the seismic stratigraphy of the mid Pleistocene-Holocene Indus Shelf David R. Limmer • Timothy J. Henstock • Liviu Giosan • Camilo Ponton • Ali R. Tabrez • David I. M. Macdonald • Peter D. Clift Received: 10 January 2012 / Accepted: 20 July 2012 Ó Springer Science+Business Media B.V. 2012 Abstract We present results from the first high-resolu- tion seismic reflection survey of the inner Western Indus Shelf, and Indus Delta, Arabian Sea. The results show major regional differences in sedimentation across the shelf from east to west, as well as north to south, both since the Last Glacial Maximum (*20 ka) and over longer time scales. We identify 10 major regional reflectors, interpreted as representing sea level lowstands. Strong compressive folding is observed underlying a reflector we have called Horizon 6 in the north-western shelf, probably compression associated with the transpressional deformation of the Murray Ridge plate boundary. Downslope profiles show a series of well developed clinoforms, principally at the shelf edge, indicating significant preservation of large packages of sediment during lowstands. These clinoforms have developed close to zones of deformation, suggesting that subsidence is a factor in controlling sedimentation and consequently erosion of the Indus Shelf. These clinoforms fan out from dome features (tectonic anticlines) mostly located close to the modern shoreline. Keywords Indus Delta Á Quaternary Á Clinoforms Á Seismic stratigraphy Introduction and regional background The stratigraphy and morphology of clastic continental margins represents the integrated result of continental- margin subsidence, sediment supply, and the effects of sea level variation. Our understanding of how margins evolve through time was greatly advanced by the introduction of sequence stratigraphic concepts by Vail et al. (1977) and subsequent related refinements, such as Haq et al. (1987). These models focused on the impacts of sea level variations and tended to ignore the role of changing sediment supply or changing rates of basement tectonic subsidence. Moreover, these models tended to view the margin in a two dimen- sional fashion, ignoring lateral migration by delta lobes or the role of submarine canyons. While it has been widely observed that the morphology and stratigraphy of conti- nental shelves reflect the interplay among sea level, sedi- ment supply, and oceanographic processes (e.g., Swenson et al. 2005; Porebski and Steel 2006; Pratson et al. 2007), the diversity of shelf architectures makes it difficult to isolate the relative importance of these processes and to develop general models of shelf stratigraphy. In areas of high sedi- ment supply, such as deltas, processes on the delta plain and inner shelf can strongly influence mid- to outer-shelf areas (Greene et al. 2007; Reijenstein et al. 2011). At a larger D. R. Limmer (&) Á D. I. M. Macdonald Á P. D. Clift School of Geosciences, University of Aberdeen, Meston Building, Aberdeen AB24 3UE, UK e-mail: d.r.limmer@abdn.ac.uk T. J. Henstock School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UK L. Giosan Á C. Ponton Department of Geology and Geophysics, Woods Hole Oceanographic Institution, 360 Woods Hole Road, Woods Hole, MA 02543, USA A. R. Tabrez National Institute of Oceanography ST-47 Block 1, Clifton, Karachi 75600, Pakistan Present Address: P. D. Clift Department of Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803, USA 123 Mar Geophys Res DOI 10.1007/s11001-012-9160-6