Coarse carbonate breccias as a result of water‐wave cyclic loading (uppermost Jurassic – South‐East Basin, France)

Abstract

In the uppermost Jurassic of the central part of the South‐East Basin of France, an association of lime mudstone beds, calcarenite beds and coarse carbonate breccia bodies form an informal stratigraphical unit called the ‘Barre Tithonique’. In the ‘Barre Tithonique’, gradual transitions from lime mudstone or calcarenite to breccia show different stages of deformation leading to progressive brecciation of the original lithologies. The study of the breccia facies, and the observed gradual transitions as a whole, document a new early diagenetic process in carbonate environments, resulting from water‐wave and seabed interaction. Water‐wave induced brecciation and its abundance in the ‘Barre Tithonique’ indicate that sea–seabed interaction was significant. Comparison with modern studies of the mechanics of wave–seabed interaction suggests that water depth was less than 200 m. It is demonstrated that sedimentary features such as channel‐like structures, previously interpreted as being the result of erosion and deposition of mud‐flows, were in fact produced by wave‐induced, in situ reworking of lime mud, without any significant unidirectional flow or gravity induced displacement.

Geochemistry of a chert breccia

“…The causes of fragmentation may differ: desiccation and mud cracking, high pore-fluid pressure (Harper and Tartarotti, 1996), dissolution-collapse (Matton et al, 2002), storm-wave action on the seabed (Bouchette et al, 2001), or seismic activity (Rodríguez-Pascua et al, 2000). The morphology of the breccias reminds one of the "mixed layers" in the Pleistocene Lisan Formation in the Dead Sea basin, which Marco and Agnon (1995) interpreted as seismites.…”

Origin of the Furongian limestone breccias in the North China Platform

“…On contrary, on the basis of detailed investigations (including intrastratal cracks, transitional changes from cracks to slightly mobilized fragments to totally disrupted clasts, different deformation behaviors of different material, and features of the underlying and overlying sediment), Chen et al (2009a) revealed that in many cases the limestone breccias were formed by intrastratal brecciation, mobilization, and further re-orientation, most likely under increased extrinsic stress (Figures 13 and 15 in Chen et al, 2009a). In fact, penecontemporaneous intrastratal brecciation, with or without subsequent mobilization, has been increasingly reported recently (e.g., Stanistreet and Hughes, 1984;Cowan and James, 1992;Pratt, 1998Pratt, , 2002Bouchette et al, 2001;Chough et al, 2001;Du et al, 2001Du et al, , 2008Kwon et al, 2002;Duranti and Hurst, 2004;Gruszka and Van Loon, 2007;Li et al, 2008;Chen et al, 2009aChen et al, , 2009bChen et al, , 2011Ettensohn et al, 2011;Chen and Lee, 2013).…”

Early diagenetic deformation structures of the Furongian ribbon rocks in Shandong Province of China—A new perspective of the genesis of limestone conglomerates

“…On the other hand, these cracks are not tectonic or dissolution in origin during late or postdiagenesis because tectonic or dissolution cracks are usually filled with sparry calcite and rhombic dolomite. Besides, tectonics-induced cracks usually cut relatively thick strata [33]. Molar-tooth structures are excluded according to the characteristics of the cracks in ribbon rocks because molar-tooth cracks are filled with micritic or sparry calcite, and are usually thicker in middle and thinner in the lower and upper part of cracks [34].…”

“…Static pressure (due to overlying seawater and sediments) is easily dissipated under normal compaction, which usually cannot trigger soft-sediment deformation [36]. Therefore, an external force as an inducing factor is needed to trigger the sediment deformation, such as seismic shock [6,[45][46][47][48][49][50], storms [33,51,52], tides [53], and waves [31,54].…”

“…Storms would cause cyclic loading at deep water depths (<150 m). Passage of large storm waves would exert cyclic loading stress on the sea floor, which induces to-and-fro motion of sediment down to several meters below the sea floor [31,33]. Therefore, differentially cemented ribbon rock sediments several meters below the sea floor would be easily triggered by storm-wave loading in the environments of epicontinental sea.…”