Palynology of the lower lefipan formation (upper cretaceous) of barranca de los perros, chubut province, Argentina. part I. Cryptogam spores and gymnosperm pollen

Baldoni, Alicia M.

doi:10.1080/01916122.1992.9989410

Cited by 33 publications

(21 citation statements)

References 18 publications

(26 reference statements)

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“…). The reconstructed SSTs range from 25.6°C to 27.1°C, in accordance with the tropical climate inferred by palynological and megafloral studies, suggesting that this region was characterized by a hinterland with rainforests with megathermal angiosperms (Baldoni ; Barreda & Palazzesi ; Iglesias et al . ; Palazzesi & Barreda ; Barreda et al .…”

Section: Discussionsupporting

confidence: 83%

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Climate and sea‐level changes across a shallow marine Cretaceous–Palaeogene boundary succession in Patagonia, Argentina

et al. 2017

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Upper Maastrichtian to lower Paleocene, coarse‐grained deposits of the Lefipán Formation in Chubut Province, (Patagonia, Argentina) provide an opportunity to study environmental changes across the Cretaceous–Palaeogene (K–Pg) boundary in a shallow marine depositional environment. Marine palynological and organic geochemical analyses were performed on the K–Pg boundary interval of the Lefipán Formation at the San Ramón section. The palynological and organic geochemical records from the San Ramón K–Pg boundary section are characteristic of a highly dynamic, nearshore setting. High abundances of terrestrial palynomorphs, high BIT‐index values and the occasional presence of plant fossils are indicative of a large input of terrestrial organic material. The organic‐walled dinoflagellate cyst (dinocyst) assemblage is generally dominated by Senegalinium and other peridinioid dinocyst taxa, indicative of high‐nutrient conditions and decreased salinities, probably associated with a large fluvial input. The reconstructed sea surface temperatures range from 25°C to 27°C, in accordance with the tropical climate inferred by palynological and megafloral studies. As in the Bajada del Jagüel section, ~500 km north‐north‐east of San Ramón, peaks of Senegalinium spp. were recorded below and above the K–Pg boundary, possibly related to enhanced runoff resulting from more humid climatic conditions. The lithological, palynological and organic geochemical records suggest the occurrence of a sea‐level regression across the K–Pg boundary, resulting in a hiatus directly at the boundary in both sections, followed by a transgression in the Danian.

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Section: Discussionsupporting

confidence: 83%

“…). Palynological and megafloral studies suggest that this region was characterized by coastal mangrove forests and swamp communities, and a hinterland with rainforests comprising megathermal angiosperms (Baldoni ; Barreda & Palazzesi ; Iglesias et al . ; Palazzesi & Barreda ; Barreda et al .…”

Section: Geological Settingmentioning

confidence: 99%

Climate and sea‐level changes across a shallow marine Cretaceous–Palaeogene boundary succession in Patagonia, Argentina

et al. 2017

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“…One hundred and thirty spore and pollen species were recovered (Table S1), of which 40 were previously reported from the lower part of the Lefipán Formation [25], [26].…”

Section: Resultsmentioning

confidence: 99%

Cretaceous/Paleogene Floral Turnover in Patagonia: Drop in Diversity, Low Extinction, and a Classopollis Spike

et al. 2012

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Nearly all data regarding land-plant turnover across the Cretaceous/Paleogene boundary come from western North America, relatively close to the Chicxulub, Mexico impact site. Here, we present a palynological analysis of a section in Patagonia that shows a marked fall in diversity and abundance of nearly all plant groups across the K/Pg interval. Minimum diversity occurs during the earliest Danian, but only a few palynomorphs show true extinctions. The low extinction rate is similar to previous observations from New Zealand. The differing responses between the Southern and Northern hemispheres could be related to the attenuation of damage with increased distance from the impact site, to hemispheric differences in extinction severity, or to both effects. Legacy effects of the terminal Cretaceous event also provide a plausible, partial explanation for the fact that Paleocene and Eocene macrofloras from Patagonia are among the most diverse known globally. Also of great interest, earliest Danian assemblages are dominated by the gymnosperm palynomorphs Classopollis of the extinct Mesozoic conifer family Cheirolepidiaceae. The expansion of Classopollis after the boundary in Patagonia is another example of typically Mesozoic plant lineages surviving into the Cenozoic in southern Gondwanan areas, and this greatly supports previous hypotheses of high latitude southern regions as biodiversity refugia during the end-Cretaceous global crisis.

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“…During the late Maastrichtian and early Danian, North and Central Patagonia experienced a warm, humid climate. Pollen records suggest rainforests, coastal mangrove forests, and swamp communities in the region [ Baldoni , ; Kiessling et al , ; Barreda and Palazzesi , ; Iglesias et al , ; Palazzesi and Barreda , ]. This vegetation type is classified as megathermal and indicates a minimal average air temperature of 24°C [ Barreda and Palazzesi , ; Palazzesi and Barreda , ; Barreda et al , ].…”

Section: Geological Settingmentioning

confidence: 99%

Latest Cretaceous climatic and environmental change in the South Atlantic region

et al. 2017

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Latest Maastrichtian climate change caused by Deccan volcanism has been invoked as a cause of mass extinction at the Cretaceous‐Paleogene (K‐Pg) boundary (~66.0 Ma). Yet late Maastrichtian climate and ecological changes are poorly documented, in particular on the Southern Hemisphere. Here we present upper Maastrichtian‐lower Danian climate and biotic records from the Bajada del Jagüel (BJ) shelf site (Neuquén Basin, Argentina), employing the TEX86 paleothermometer, marine palynology (dinoflagellate cysts), and micropaleontology (foraminifera). These records are correlated to the astronomically tuned Ocean Drilling Program Site 1262 (Walvis Ridge). Collectively, we use these records to assess climatic and ecological effects of Deccan volcanism in the Southern Atlantic region. Both the TEX86‐based sea surface temperature (SST) record at BJ and the bulk carbonate δ18O‐based SST record of Site 1262 show a latest Maastrichtian warming of ~2.5–4°C, at 450 to 150 kyr before the K‐Pg boundary, coinciding with the a large Deccan outpouring phase. Benthic foraminiferal and dinocyst assemblage changes indicate that this warming resulted in enhanced runoff and stratification of the water column, likely resulting from more humid climate conditions in the Neuquén Basin. These climate conditions could have been caused by an expanding and strengthening thermal low over the South American continent. Biotic changes in response to late Maastrichtian environmental changes are rather limited, when compared to the major turnovers observed at many K‐Pg boundary sites worldwide. This suggests that environmental perturbations during the latest Maastrichtian warming event were less severe than those following the K‐Pg boundary impact.

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Palynology of the lower lefipan formation (upper cretaceous) of barranca de los perros, chubut province, Argentina. part I. Cryptogam spores and gymnosperm pollen

Cited by 33 publications

References 18 publications

Climate and sea‐level changes across a shallow marine Cretaceous–Palaeogene boundary succession in Patagonia, Argentina

Climate and sea‐level changes across a shallow marine Cretaceous–Palaeogene boundary succession in Patagonia, Argentina

Cretaceous/Paleogene Floral Turnover in Patagonia: Drop in Diversity, Low Extinction, and a Classopollis Spike

Latest Cretaceous climatic and environmental change in the South Atlantic region

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