Triassic carbonate submarine fans along the Arabian platform margin, Sumeini Group, Oman

Abstract

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 coarsegrained 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.

Submarine lobes and feeder channels of redeposited, temperate carbonate and mixed siliciclastic‐carbonate platform deposits (Vera Basin, Almería, southern Spain)

“…Although it appears that temperate carbonates are more prone to being mobilized than tropical carbonates because the latter commonly undergo early sea¯oor diagenesis (Tucker, 1992b), most of the redeposited turbiditic carbonate examples described in the literature (e.g. Ruiz-Ortiz, 1983;Watts, 1988;Cooper, 1989;Tucker, 1992a;Miller & Heller, 1994) have been interpreted as being tropical in character. This suggests that some examples may require reinterpretation to reassess the climatic context in which they formed.…”

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“…A combined classification scheme of FOLK (1962), DUN HAM (1962) and EMBRY & KLOVAN (1971) was followed for carbonate rocks. The classification of FLÜGEL (2004) was used to differentiate the samples according to the proposed Standard Microfacies Classification (SMF) to understand the depositional characteristics (PRICE, 1977;WATTS, 1987;REIJMER et al, 2008REIJMER et al, , 2012HAAS et al, 2010;RUBERT et al, 2012).…”

“…Provence Basin, TuronianCenomanian, France (REIJMER et al, 2008(REIJMER et al, , 2012REIJMER et al, 2015aREIJMER et al, , 2015b; the Late Triassic Early Jurassic of Northern Hungary (HAAS et al, 2010); Jurassic Tethys Oceanic Carbonate deposits of Eastern AlpsSwitzerland (EBERLI, 1987); the Early Cretaceous of the Manim unit, West ern Carpathians Slovakia (MICHALIK et al, 2012); the Late Cretaceous of the Ionian BasinCentral Albania (DEWEVER et al, 2007) and the Cretaceous of the Othris MountainHellenide zone and Eastern Greece (PRICE, 1977). Some older calciturbi dites were reported in different countries; the SilurianDevonian calciturbidites of the Barrandian RegionCzech Republic, (VA CEK, 2007); the EarlyMiddle Triassic Sumeini Group, Maqam Formation, northernmost Arabian Carbonate Platform (WATTS, 1987); and the Triassic Pedata / Potschen Formation calciturbi ditesAustria (REIJMER et al, 1991).…”

“…Calciturbidites occur in various sedimentary environments such as continental slopes, toe of slope and single or multiple feeding submarine fans (WATTS, 1987;RUBERT et al, 2012;HAIRA BIAN et al, 2015). They can also be associated with different parts of carbonate platforms and platform margins (REIJMER et al, 2015a(REIJMER et al, , 2015b.…”

Sedimentary processes in a submarine canyon excavated into a temperate‐carbonate ramp (Granada Basin, southern Spain)

“…Outcrops of ancient submarine canyons in carbonates are scarce (Watts, 1988;Braga et al, 2001;Ruíz-Ortíz et al, 2006), and examples of ancient siliciclastic counterparts are not very common either (Stanley, 1967;Druckman et al, 1995;Anderson et al, 2006), probably due to their large scale (Normark et al, 1983/84). The few examples of sub-Recent to Present submarine canyons in non-tropical ramps described until now are all southern Australian basins (Leach & Wallace, 2001;Mitchell et al, 2007a); the most representative example is the Bass Canyon (Pliocene to Recent) (Conolly, 1968;Mitchell et al, 2007b).…”