Ocorrência de Ophiomorpha nodosa em sedimentos pleistocênicos da Planície Costeira da Pinheira, Santa Catarina, Brasil

Abstract

Occurrence of Ophiomorpha nodosa in Pleistocene sediments of Coastal Plain of Pinheira, Santa Catarina, Brazil. The occurrence of Pleistocene (MIS) 5 marine ichnofossils in a locality of the Coastal Plain of Pinheira, State of Santa Catarina is described, and their value as indicators of the geological/stratigraphical evolution in this area is discussed. This sedimentary sequence indicates the transition among the subtidal zone, where the ichnofossils occur, to the supratidal zone, and finally to dunes. The ichnofossils can be seen in vertical view, between 0 and 4.5 m above the present sea level. The galleries are cylindrical structures with circular or oval transversal section, without ramifications. Their interior walls are smooth, and the exterior walls are composed of pellets made of clay and sand homogeneously dispersed, without a specific arrangement. This morphology is related to ichnospecies Ophiomorpha nodosa. The average density was 32.9 galleries/ m², ranging from 22 to 51 galleries/m². The highest density found could be related to time-averaging, or to a deeper subtidal environment. The vertical distribuition of Ophiomorpha and the absence of faciological variations in the deposits might indicate an aggradational stage between the trangressive and regressive phases.

On ex situOphiomorphaand other burrow fragments from the Rio Grande do Sul Coastal Plain, Brazil: paleobiological and taphonomic remarks

“…Ichnotaxonomic identifications of the ex situ specimens were based on the literature (e.g., Kennedy and MacDougall, 1969; Frey et al, 1978; Griffis and Suchanek, 1991; Nickell and Atkinson, 1995; Bromley and Edkale, 1998; Bertling et al, 2006; Gibert et al, 2006; Uchman, 2009; Netto et al, 2012, 2017; Angulo and Souza, 2014; Martins et al, 2018; Rindsberg, 2018), as well as direct comparison with the materials found in situ in the Chuí Formation cropping out at Osório, Santa Vitória do Palmar, and Chuí municipalities (Rio Grande do Sul, Brazil). Ophiomorpha nodosa specimens from the Chuí Formation housed at the Laboratório de História da Vida e da Terra, Universidade do Vale do Rio dos Sinos (LAVIGEA-UNISINOS; N = 8), and Laboratório de Geologia e Paleontologia, Universidade Federal do Rio Grande (LGP-FURG; N = 3) were also analyzed.…”

“…More particularly, Ophiomorpha can serve as a proxy for paleoshorelines (Hyžný et al, 2018) and, consequently, of sea-level changes. In situ Ophiomorpha have been reported in distinct geological units of Brazil (Rossetti et al, 2000;Gingras et al, 2002;Netto and Rossetti, 2003;Tognoli and Netto, 2003;Rossetti and Góes, 2009;Martins et al, 2018). In the particular case of the Rio Grande do Sul Coastal Plain (RSCP), Ophiomorpha nodosa Lundgren, 1891 and Ophiomorpha puerilis Gibert et al, 2006 occur in situ in the emerged deposits of the Upper Pleistocene Chuí Formation (Villwock and Tomazelli, 1995;Gibert et al, 2006;Netto et al, 2012Netto et al, , 2017Lopes, 2013).…”

“…Pedrol de Freitas et al-Ex situ fossil crustacean burrows from Quaternary of Brazil not compared with specimens of in situ O. nodosa from the Chuí Formation(Gibert et al, 2006). However, in situ O. nodosa from Pleistocene deposits at the Pinheira coastal plain (Santa Catarina State, Brazil) presented an external diameter ranging 22.86 −32.82 mm (mean 27.84 mm;Martins et al, 2018), which are values occurring within the ex situ O. nodosa range but are not as wide. Also, specimens of in situ O. nodosa from England presented a 60 mm maximum diameter…”

A review of Last Interglacial sea-level proxies in the Western Atlantic and Southwestern Caribbean, from Brazil to Honduras

“…MSL MSL -4m Frey et al, 1978Martins et al, 2018 Tidal notch Definition by Antonioli et al, 2015: "Indentations or undercuttings cut into rocky coasts by processes acting in the tidal zone (such as tidal wetting and drying cycles, bioerosion, or mechanical action)".…”

“…Other elevation measurement methods include differential GPS, metered tape or rod, topographic map, and total station (Figure 2a). Among these, the most accurate technique is differential GPS, used by Tomazelli and Dillenburg (2007) and Martins et al (2018) in Brazil to report the elevations for the maximum height of Ophiomorpa burrows. Differential GPSs were also used by Muhs et al (2012) and Lorscheid et al (2017) in Curaçao and Bonaire, respectively.…”