Triassic Carbonate Submarine Fans Along the Arabian Platform Margin, Sumeini Group, Oman
- Dorrik A. V. Stow
Published Online: 29 APR 2009
Copyright © 1992 The International Association of Sedimentologists
Deep-Water Turbidite Systems
How to Cite
Watts, K. F. (1991) Triassic Carbonate Submarine Fans Along the Arabian Platform Margin, Sumeini Group, Oman, in Deep-Water Turbidite Systems (ed D. A. V. Stow), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304473.ch38
Department of Geology, University of Southampton, UK
- Published Online: 29 APR 2009
- Published Print: 11 NOV 1991
Print ISBN: 9780632032624
Online ISBN: 9781444304473
- continental margin slope;
- carbonate submarine fans;
- coarsegrained redeposited carbonate;
- calciclastic sediment;
- mid-fan channel complexes
The Sumeini Group formed along the passive continental margin slope that bounded the northeastern edge of the Arabian carbonate platform. With the initial development of this passive continental margin in Oman during Early to Middle Triassic time (possibly Permian), small carbonate submarine fans of the C Member of the Maqam Formation developed along a distally steepened slope.
The fan deposits occur as several discrete lenticular sequences of genetically related beds of coarse-grained redeposited carbonate (calciclastic) sediment within a thick interval of basinal lime mudstone and shale. Repeated pulses of calciclastic sediment were derived from ooid shoals on an adjacent carbonate platform and contain coarser intraclasts eroded from the surrounding slope deposits. Sediment gravity flows, primarily turbidites with lesser debris flows and grain flows, transported the coarse sediments to the relatively deep submarine fans. Channel erosion was a major source of intraformational calcirudite.
Two small submarine fan systems were each recurrently supplied with calciclastic sediment derived from point sources, submarine canyons. The northern fan system retrogrades and dies out upsection. The southern fan system was apparently longer-lived; calciclastic sediments in it are more prevalent and occur throughout the section. The proximal portions of this fan system are dominated by channelized beds of calcirudite which represent inner- to mid-fan channel complexes. The distal portions include mostly lenticular, unchannelized beds of calcarenite, apparently mid- to outer-fan lobes.
Carbonate submarine fans appear to be rare in the geological record in comparison with more laterally continuous slope aprons of coarse redeposited sediment. The carbonate submarine fans of the C Member apparently formed by the funnelling of coarse calciclastic sediment into small submarine canyons which may have developed due to rift and/or transform tectonics. The alternation of discrete sequences of calciclastic sediment with thick intervals of ‘background’ sediment resulted from either sea-level fluctuations or pulses of tectonic activity.