Paleosols of the Maastrichtian dinosaur-bearing Chorrillo Formation (southern Patagonia, Argentina): Paleoenvironmental and paleoclimate implications

Raigemborn, María Sol; Lizzoli, Sabrina; Paz, Damián Moyano; Varela, Augusto Nicolás; Poiré, Daniel Gustavo; Valeria,; Vera, Ezequiel Ignacio; Manabe, Makoto; Novas, Fernando E.

doi:10.1016/j.cretres.2023.105587

Cited by 5 publications

(4 citation statements)

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“…The high content of organic matter in this bed suggests that vegetation grew in proximity to the swamp/pond favoring the development of the Histosol-like paleosol. The poorly decomposed state of the organic matter indicates anoxic and reducing conditions in the bottom water of the swamp/pond 72 , 82 , 83 , which may also favor the exceptional preservation of non-mineralized organisms such as the arthropods here studied.…”

Section: Methodsmentioning

confidence: 92%

“…This bed accumulated in a waterlogged, low energy, environment as a swamp/pond, located in the distal areas of the low-gradient floodplain of the fluvial system, as the product of fluvial overbank processes 17 , 22 . This swamp/pond deposits are vertically related to Histosol-like paleosols 72 . The high content of organic matter in this bed suggests that vegetation grew in proximity to the swamp/pond favoring the development of the Histosol-like paleosol.…”

Section: Methodsmentioning

confidence: 92%

“…These austral taxa generally inhabit cool, pristine environments, often upland to montane streams 61 . Noteworthy, some floristic elements recovered from the Chorrillo Formation, as well as paleosoil analysis, contrarily indicate temperate to warm conditions 23 , 72 .…”

Section: Discussionmentioning

confidence: 99%

“…7C and 8 ) interpreted as accumulated in a low gradient fluvial environment dominated by thick fine-grained floodplain deposits which alternate with channel-shaped and lobe-shaped sandstone bodies interpreted and fluvial channels and crevasse splay facies 17 . The fine-grained deposits constitute more than 60% of the unit and show evidence of both soil development and waterlogging 17 , 22 , 72 . The Chorrillo Formation was initially named as ‘dinosaur-bearing strata’ because of the abundance of fossil vertebrate remains that were found on these deposits 14 – 16 , 19 – 21 , 80 , 81 .…”

Section: Methodsmentioning

confidence: 99%

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A Maastrichtian insect assemblage from Patagonia sheds light on arthropod diversity previous to the K/Pg event

Vera,

Monferran,

Massaferro

et al. 2023

Commun Biol

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Insect faunas from the latest Cretaceous are poorly known worldwide. Particularly, in the Southern Hemisphere, there is a gap regarding insect assemblages in the Campanian-Maastrichtian interval. Here we present an insect assemblage from the Maastrichtian Chorrillo Formation, southern Argentina, represented by well-preserved and non-deformed, chitinous microscopic remains including head capsules, wings and scales. Identified clades include Chironomidae dipterans, Coelolepida lepidopterans, and Ephemeroptera. The assemblage taxonomically resembles those of Cenozoic age, rather than other Mesozoic assemblages, in being composed by diverse chironomids and lepidopterans. To the best of our knowledge, present discovery constitutes the first insect body fossils for the Maastrichtian in the Southern Hemisphere, thus filling the gap between well-known Early Cretaceous entomofaunas and those of Paleogene age. The presented evidence shows that modern clades of chironomids were already dominant and diversified by the end of the Cretaceous, in concert with the parallel radiation of aquatic angiosperms which became dominant in freshwater habitats. This exceptional finding encourages the active search of microscopic remains of fossil arthropods in other geological units, which could provide a unique way of enhancing our knowledge on the past diversity of the clade.

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Section: Methodsmentioning

confidence: 92%