The influence of coastal evolution on the paleobiogeography of the bivalve Anomalocardia flexuosa (Linné, 1767) along the southwestern Atlantic Ocean

Lopes, Renato Pereira; Ritter, Matias do Nascimento; Barboza, Eduardo Guimarães; Rosa, Marcelo Prado Amaral; Dillenburg, Sérgio Rebello; Caron, Felipe

doi:10.1016/j.jsames.2021.103662

Cited by 3 publications

(7 citation statements)

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“…2G). The mollusks are mostly coastal marine species, but a few specimens of two bivalves that inhabit low-energy, fully saline to brackish lagoon environments ( Anomalocardia flexuosa and Erodona mactroides ) were also found (Bettinelli et al, 2018; Lopes and Pereira, 2018; Lopes et al, 2022). The microfossil assemblage is dominated by rotaliid foraminifers characteristic of coastal marine to lagoon environments ( Elphidium discoidale , Ammonia beccari , and Buccella peruviana ).…”

Section: Resultsmentioning

confidence: 99%

“…For example, the shell material recovered from the LB facies differs from the more diverse and larger marine shells found at the bottom of the permanent modern estuarine channel connecting the Patos Lagoon (Fig. 1C) to the ocean, subject to strong hydrodynamics (Lopes et al, 2022).…”

Section: Discussionmentioning

confidence: 96%

“…Nevertheless, the OSL ages > 128 ka obtained in the MIS 5c unit (Barrier IIIc) at AC-02 indicate sediments eroded from preexisting MIS 6 and MIS 5e deposits. The relative abundance in the putative subsurface MIS 5a deposit (Barrier IIIa) of estuarine bivalves A. flexuosa and E. mactroides , an association characteristic of lagoon settings in the CPRS (Bettinelli et al, 2018; Lopes et al, 2022) on the seaward side of the barrier, suggests erosion of a lagoon deposit from the MIS 5c subunit by a sea-level oscillation, indicated by the marine shells with ages > 101 ka (Fig. 9).…”

Section: Discussionmentioning

confidence: 97%

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Stratigraphy and evolution of the late Pleistocene (MIS 5) coastal Barrier III in southern Brazil

Lopes,

Pereira,

Caron

et al. 2024

Quat. res.

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The structure and origin of the Pleistocene (Marine Isotope Stage [MIS] 5) coastal Barrier III in southern Brazil were investigated through analysis of lithofacies, numerical ages, and ground-penetrating radar (GPR) data obtained in outcrops and subsurface deposits. The stratigraphic succession is characteristic of transgressive barriers, with muddy lagoon bottom facies unconformably overlying an older unit (Barrier II) and overlain by landward-dipping lagoon margin and aeolian facies. The back-barrier lagoon was filled with sediments and shells transferred from the foreshore through overwash and/or inlets during the MIS 5e transgressive-high-stand phase, with a higher sea level that reached about +6 to +7 m relative to the present. Marine sediments and shells on the seaward side of the barrier dated to ~100–106 ka indicate another high stand at +4 to +5.1 m during MIS 5c. One shell dated to ~87 ka and aeolian deposits dated to ~82 and ~85 ka suggest a third high stand during MIS 5a that reached at least −2 m relative to the present. The two (possibly three) juxtaposed marine deposits show that Barrier III is a more complex unit than previously recognized, built by successive orbitally forced eustatic sea-level oscillations also recorded in other deposits along the Brazilian coast and worldwide.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 97%

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Stratigraphy and evolution of the late Pleistocene (MIS 5) coastal Barrier III in southern Brazil

Lopes,

Pereira,

Caron

et al. 2024

Quat. res.

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“…Considering the geological history of the RSCP this mixture could have been the result of sea-level rise on the barrier-lagoon systems of the RSCP driven by glacial-interglacial cycles. That process causes the exposure and erosion of lagoon deposits on the shoreface due to landward migration of barriers on top of those deposits, as recorded in sectors of the Holocene Barrier IV, including the northern RSCP (Tomazelli & Villwock, 1991;Dillenburg, 1996;Campos et al, 2021;Lopes et al, 2022). The change from lagoon to fully marine environments is indicated by mixed Holocene assemblages of estuarine and marine invertebrates in Mirim and Patos Lagoons (Santos-Fischer et al, 2018;Lopes et al, 2021Lopes et al, , 2022.…”

Section: Discussionmentioning

confidence: 98%

“…That process causes the exposure and erosion of lagoon deposits on the shoreface due to landward migration of barriers on top of those deposits, as recorded in sectors of the Holocene Barrier IV, including the northern RSCP (Tomazelli & Villwock, 1991;Dillenburg, 1996;Campos et al, 2021;Lopes et al, 2022). The change from lagoon to fully marine environments is indicated by mixed Holocene assemblages of estuarine and marine invertebrates in Mirim and Patos Lagoons (Santos-Fischer et al, 2018;Lopes et al, 2021Lopes et al, , 2022. The available data, however, do not permit to infer the degree of temporal mixing, the proportion of reworked specimens, or their respective absolute ages.…”

Section: Discussionmentioning

confidence: 99%

Paleoecological characterization of ostracods in beachrocks from the Northern sector of the Rio Grande do Sul Coastal Plain, Brazil

Bergue¹,

Lopes²,

Caron³

et al. 2022

Rev. bras. paleontol.

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A micropaleontological analysis on 15 beachrock samples from the Northern sector of Rio Grande do Sul Coastal Plain (RSCP ), southern Brazil , revealed a relatively diverse and well-preserved ostracod assemblage composed of 16 species , including Cyprideis multidentata Hartmann, Callistocythere nucleoperiscum Whatley et al., Cytheretta punctata Sanguinetti, Caudites ohmerti Coimbra & Ornellas , and Argenticytheretta levipunctata Sanguinetti et al. Eleven ostracod species are left in open nomenclature or tentatively identified . Besides ostracods , some foraminifers , echinoderm spines, and fish remains (teeth) were also recovered ; however , the scarcity of specimens or poor preservation precluded identification at species level. Based on the Ostracoda taxonomic composition it is proposed that the beachrocks characterize environmentally condensed assemblages . This preliminary study reveals the importance and potentiality of micropaleontology for understanding the processes involved in the formation of beachrocks. Keywords: Pelotas Basin, Quaternary, coastal environments, micropaleontology, taphonomy.

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Fossiliferous sites of the southern coast of Rio Grande do Sul state, Brazil: geoheritage records of Quaternary sea-level, climate and environmental changes

Lopes,

Pereira,

Ritter

et al. 2024

JGSB

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The southern coastal plain of Rio Grande do Sul state hosts essential fossil records of both marine and terrestrial faunas that have provided invaluable information about the geological and environmental Quaternary history of southern Brazil. These fossils are found in surface and subsurface deposits on sites stretching from the continental shelf up to coastal lagoons inland. The sites on the shelf are time-averaged lag deposits formed of marine and terrestrial fossils exhumed and mixed together as a result of erosion of the original deposits by sea-level oscillations. Although lacking any precise stratigraphic context, the available numerical dates indicate Middle to late Pleistocene ages. Fossils removed from the shelf by waves today form large Konzentratt-Lagerstätten on the beach, called concheiros. The sites on continental areas occur in barrier-lagoon depositional systems, and include marine deposits formed under higher than present sea levels formed by Middle and late Pleistocene and Early-Middle Holocene marine transgressions. The fossiliferous sites with well-defined stratigraphic context encompass fluvial and aeolian (loess) deposits and paleosols associated with the Middle-late Pleistocene Santa Vitória Alloformation and Cordão Formation outcropping along Chuy Creek. Fossils of late Pleistocene terrestrial and Holocene marine organisms were collected from the bottom and marginal terraces of Mirim Lagoon. Although most sites are not directly under threat today, their wide distribution poses potential problems for protection. Current protection measures for the sites and associated fossils include requests by environmental agencies for preliminary surveys and fossil rescue programs prior to construction projects, and the proposal of a marine-coastal protected area is currently under consideration. Educational programs with schools and exhibits for the general public executed by the museums in the town of Santa Vitória do Palmar have contributed to public awareness about the importance of the regional paleontological heritage and have produced positive feedback and results that increased the number of known fossiliferous sites in the region thanks to communication by local people. These actions are essential to establish protection measures in case new developments emerge in the future that could threaten the sites and their fossils.

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The influence of coastal evolution on the paleobiogeography of the bivalve Anomalocardia flexuosa (Linné, 1767) along the southwestern Atlantic Ocean

Cited by 3 publications

References 116 publications

Stratigraphy and evolution of the late Pleistocene (MIS 5) coastal Barrier III in southern Brazil

Stratigraphy and evolution of the late Pleistocene (MIS 5) coastal Barrier III in southern Brazil

Paleoecological characterization of ostracods in beachrocks from the Northern sector of the Rio Grande do Sul Coastal Plain, Brazil

Fossiliferous sites of the southern coast of Rio Grande do Sul state, Brazil: geoheritage records of Quaternary sea-level, climate and environmental changes

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