Florida Bay: Modern analogue for Lofer cyclothems?

Abstract

Lofer cyclothems of the Alpine Upper Triassic have many features in common with Holocene sediments of Florida Bay. The modal ‘complete’ Lofer cycle is essentially symmetrical, having a deepening and shoaling phase, as does the cycle‐in‐progress in Florida Bay. Lateral discontinuity and thickness variations within members of the Lofer cyclothems indicate syn‐depositional relief, possibly in the form of mud banks, the signature feature of Florida Bay sedimentation. Spatial and temporal dimensions, although poorly constrained, appear comparable. Analogous depositional textures, biota and sedimentary structures, while not unique to either environment, strengthen the inferences that can be made about the Triassic depositional environment and regarding future evolution of the modern environment. The striking similarities between the Holocene icehouse sediments and the Late Triassic greenhouse deposits suggest that sedimentation patterns at the scale of individual cycles or parasequences may be largely independent of the global climate regime.

A mud-dominated coastal plain to lagoon with emerged carbonate mudbanks: The imprint of low-amplitude sea level cycles (mid-Upper Cretaceous, South Iberian Ramp)

“…Lofer cyclothems of the Alpine Upper Triassic have also many features in common with Holocene sediments of Florida Bay. In this case, lateral discontinuity and thickness variations indicate syndepositional relief, possibly in the form of mudbanks (Enos and Samankassou, 2022). The example of La Cañadilla Fm shown here, add a new example of mosaic of facies, in which carbonate mudbanks, were probably synsedimentary-cemented and formed a key belt protecting the interior ponds and coastal plain.…”

“…In the case of mudbanks of La Cañadilla Fm, sysnsedimentary cementation of muddy sediments (as indicate the presence of fenestral porosity) could have been a key process for stabilization of the mudbanks. It has to be noted that the search for Florida Bay analogues in ancient rocks is hampered by the low relief on the mudbanks (Enos and Samankassou, 2022). The slopes on the flanks of the mounds are generally less than <1°, even in the narrow banks of the eastern Bay (Enos and Perkins, 1979).…”

“…In particular, the paleoenvironment reconstructed for this carbonate-mud dominated formation can be compared with modern analogues such as the carbonate shallow systems of the southern Florida coast (Lacovara et al, 2003), which has been regarded as a modern analogue of other mud-dominated coastal to shallow carbonates in the stratigraphic record (e.g. Enos and Samankassou, 2022).…”

Sedimentology and biostratigraphy of the upper Triassic carbonates from the Shiriya cape, North Kitakami Belt, Japan

“…Moreover, the megalodontid‐rich layers, forming sequences (Figure 5) made of mudstone gradually evolving to a megalodontid boundstone layers might be related to the well–known Lofer Cycles. Those cycles are widely described in tropical lagoonal deposits in Panthalassa (Peyrotty, Rigaud, et al, 2020), in the Dachstein limestone from Tethys (Cozzi et al, 2005; Enos & Samankassou, 1998; Haas et al, 2007; Satterley & Brandner, 1995) and, more recently, compared with modern analogs in the Florida Bay (Enos & Samankassou, 2022). Another facies is also recognized from the dark massive limestone and is defined as a peloidal packstone to grainstone (MF2) with green algae.…”

Understanding carbonate factories through palaeoecological and sedimentological signals – Tribute to Luis Pomar

“…The nature and significance of high-frequency carbonate facies cycles and parasequences developed during greenhouse, transitional and icehouse times remain a first-class topic in carbonate research. Enos & Samankassou (2022) provide a critical comparison in terms of facies types and architecture, internal cyclicity, cycle thickness and lateral extent between the typical upper Triassic platform top (Lofer) cyclothems and the Holocene sediment cover of the Florida Bay. This contribution finds striking similarities between both examples of shallow-water, mud-dominated successions and raises several key questions on the validity of the models for parasequences and sedimentary cycle stacking patterns established for platform successions developed during greenhouse and icehouse times.…”