Tabular Cross-Bedding in Messinian Fluvial Channel Conglomerates, Southern Alps, Italy
- J. D. Collinson and
- J. Lewin
Published Online: 29 APR 2009
Copyright © 1983 The International Association of Sedimentologists
Modern and Ancient Fluvial Systems
How to Cite
Massari, F. (1983) Tabular Cross-Bedding in Messinian Fluvial Channel Conglomerates, Southern Alps, Italy, in Modern and Ancient Fluvial Systems (eds J. D. Collinson and J. Lewin), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303773.ch23
- Published Online: 29 APR 2009
- Published Print: 7 FEB 1983
Print ISBN: 9780632009978
Online ISBN: 9781444303773
- tabular cross-bedding – Messinian fluvial channel conglomerates, Southern Alps, Italy;
- channelized fluvial conglomerates;
- deltaic progradation;
- interchannel sediments;
- conglomeratic bodies
Channelized fluvial conglomerates of Messinian age are related to a fan-delta system active along an actively subsiding tectonic margin. They can be followed from an active fan-delta zone to an inferred interlobe area, along a belt oriented transversely to the palaeocurrents.
In the active fan-delta area the conglomeratic bodies are complex as a result of vertical stacking of channel deposits, and are dominated by facies Gm (code of Miall, 1978). They grade laterally into uni-storey interlobe sequences isolated in thick mudstones and dominated by facies Gp; a well-developed association of supraplatform facies is also present in the interlobe sequences including sheet sandstones and conglomerates, chute channels and chute bars. These changes are believed to represent a deepening and an increase in sinuosity of the channels, which are inferred to be respectively dominated by longitudinal and transverse bars.
The unimodal orientation of foresets in facies Gp suggests an essentially downstream movement of transverse bars during short-lived and pronounced flood peaks and limited subsequent modification of high-stage features during falling and low stages. The Messinian channel conglomerates are thought to be an ancient counterpart of present-day Nueces River deposits (Gustavson, 1978).