Decoding downstream trends in stratigraphic grain size as a function of tectonic subsidence and sediment supply

Research Article| July 01, 2011 Decoding downstream trends in stratigraphic grain size as a function of tectonic subsidence and sediment supply Alexander C. Whittaker; Alexander C. Whittaker † 1Department of Earth Science and Engineering, Royal School of Mines, Imperial College, London SW7 2AZ, UK †E-mail: a.whittaker@imperial.ac.uk Search for other works by this author on: GSW Google Scholar Robert A. Duller; Robert A. Duller 1Department of Earth Science and Engineering, Royal School of Mines, Imperial College, London SW7 2AZ, UK Search for other works by this author on: GSW Google Scholar Joshua Springett; Joshua Springett 2ExxonMobil, Leatherhead, Surrey KT22 8UX, UK Search for other works by this author on: GSW Google Scholar Rosie A. Smithells; Rosie A. Smithells 3Earth Science and Geography, School of Physical and Geographical Sciences, Keele University, William Smith Building, Keele, Staffordshire ST5 5BG, UK Search for other works by this author on: GSW Google Scholar Amy L. Whitchurch; Amy L. Whitchurch 1Department of Earth Science and Engineering, Royal School of Mines, Imperial College, London SW7 2AZ, UK Search for other works by this author on: GSW Google Scholar Philip A. Allen Philip A. Allen 1Department of Earth Science and Engineering, Royal School of Mines, Imperial College, London SW7 2AZ, UK Search for other works by this author on: GSW Google Scholar GSA Bulletin (2011) 123 (7-8): 1363–1382. https://doi.org/10.1130/B30351.1 Article history received: 14 Jun 2010 rev-recd: 06 Aug 2010 accepted: 08 Aug 2010 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Alexander C. Whittaker, Robert A. Duller, Joshua Springett, Rosie A. Smithells, Amy L. Whitchurch, Philip A. Allen; Decoding downstream trends in stratigraphic grain size as a function of tectonic subsidence and sediment supply. GSA Bulletin 2011;; 123 (7-8): 1363–1382. doi: https://doi.org/10.1130/B30351.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Downstream grain-size fining in stratigraphy is driven primarily by selective deposition of sediment, and the long-term efficiency of this process is determined by: (1) the magnitude and characteristics of the input sediment supply; (2) the spatial distribution of subsidence rate, which creates accommodation for sediment preservation; and (3) the dynamics of sediment transport and deposition. A key challenge is to determine how these first two factors control the caliber and spatial distribution of deposits over time scales of 104–106 yr without incorporating sediment transport details that are largely unknowable for time-averaged stratigraphy in the geological past. We address this using grain-size data collected from fluvial conglomerates in the Eocene Pobla Basin, Spanish Pyrenees, a synorogenic basin where the timing of sediment deposition is well-constrained; the sediment budget is closed; and good exposure enables time lines within stratigraphy to be picked out unambiguously. For successive stratigraphic horizons, downstream trends in grain size and composition are derived for basin-filling sediment-routing systems with length scales of 6 and 40 km, respectively. Our data show that the rate of grain-size fining varies over time and with system length and can be linked to changes in source area. These results are contrasted with grain-size data from the Antist Group, a 60-km-long Oligocene system that mantles the Southern Pyrenees, where very slow rates of grain-size fining on the wedge top of this fold-and-thrust belt are observed. We apply a self-similarity–based selective deposition model to quantify the competing controls of tectonic subsidence and sediment supply on derived grain-size trends, and model results are compared with independent constraints on the Eocene–Oligocene evolution of the Pyrenees. Our results suggest that it is now possible to invert time-averaged grain-size trends in stratigraphy to gain quantitative information on the geological boundary conditions governing the evolution of sedimentary basins. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.