Vertical and lateral building of river sandstone bodies, Ebro Basin, Spain

Abstract

Six examples of river sandstone bodies are described from well exposed sections of Oligocene and Miocene age in the Ebro Basin, northern Spain. Three of these are of ribbon form, varying in cross-section from 10 m wide × 2 m high to 20 m wide × 9 m high. In plan these ribbons vary from straight to highly sinuous. The sandstone bodies, in two cases, are multi-storey, clearly demonstrating a series of vertical building episodes. The fourth sandstone body may have a ribbon or sheet geometry, and is of special interest because it demonstrates lateral building by a laterally migrating channel, as well as some vertical building. The fifth and sixth sandstone bodies are of sheet geometry, and demonstrate lateral migration of channels and depositional surfaces. Factors that appear to be most important in determining whether a river migrates laterally or remains stable laterally are: (1) river mean flow strength, (2) bank strength, (3) flood periodicity and duration, (4) vertical movement of the alluvial area.

High Resolution Facies Record on Late Holocene Flood Plain Sediments from Lower Reaches of Narmada Valley, Western India

“…Each cluster is referred to as sediment subfacies in this paper (Figs.3,4 and 5). The nomenclature of sediment subfacies is based on the abundance of grain size and primary sedimentary structures in line with litho-facies classification after Martins (1965), Friedman (1967), Jackson (1975), Miall (1978Miall ( , 1985, Friend et al (1979), Friend et al (1986) and Martinius (2000). In the present study, the 802 cm thick Uchediya sequence was classified into two broad sedimentary facies namely sandy facies (68%) and muddy facies (32%).…”

“…The sediment facies and their subfacies were analyzed using a statistical approach supplemented with sedimentological observation in field (largely following after Friend et al 1986;Friend et al 1979;Martinius, 2000). Grain size data of Uchediya sequence (401samples) was initially processed using cluster analysis.…”

Facies analysis, stratigraphic architecture and depositional environments of the Guanajuato conglomerate in the Sierra de Guanajuato, Mexico

“…Stories form because of shifting or avulsion of active stream tracts, probably during major flood events and space accommodation (e.g. Subsidence) (Friend et al, 1979). Erosion and deposition within a story may record a single large event or several smaller events.…”

Outcrop architecture of a fluvio-lacustrine succession: Upper Triassic Yanchang Formation, Ordos Basin, China

“…The undulating scour surface and associated occurrence of mud pebble clasts and fossilized plant-stem debris at the bottom base of the formation demonstrates the action of a scour and fill process. The two juxtaposed lenticular sand bodies, which internally comprise trough and tabular cross-bedded sets and parallel bedded sets of sandstone, arose via barform migration within a channelized setting (Walker, 1978;Friend, 1979). By contrast, the interbedded thin sandstone-mudstone layers in the upper part of the studied outcrop record repeated shifts between episodes of quiescence and the accumulation of floodplain sediments (FF), and a moderate energy regime that is typical in natural levee (LV) and crevasse spray (CS) settings (e.g.…”