Very small theropod footprints from Imilchil, Morocco + hadrosaur bones with beetle feeding traces + Deccan volcanism and Chicxulub impact + Coniacian–Maastrichtian sea temperatures
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Ben Creisler
Aug 22, 2024, 9:42:46 PMAug 22
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Ben Creisler
Some recent Mesozoic papers:
Free pdf:
Judit MINGUEZ CENICEROS, Moussa MASROUR, Mohamed BOUTAKIOUT, José Ignacio EXTREMIANA & Félix PÉREZ-LORENTE (2024)
Analysis of very small-small theropod footprints data from Imilchil tracksite (Hig Central Atlas. Morocco). A concordance model for a global scale.
Journal of African Earth Sciences 105389
doi: https://doi.org/10.1016/j.jafrearsci.2024.105389
https://www.sciencedirect.com/science/article/pii/S1464343X2400222X
Highlights
The study of the ichnitic outcrops of Imilchil has shown that theropod tracks, projected according to their length, are distributed in separate groups. One of the separate groups contains very small and small footprints. Based on the ichnological data provided by Farlow, we have projected the theropod footprint data from the world's sites by size. It is observed that this distribution is repeated on a global scale and that throughout the record certains small footprints are scarce. The causes of this absence may be several, and we propose a combination of the presence of dinosaurs that are small in the adult and senil state and a change in ecological niche (ONS) for dinosaurs that in the adult state have medium and larger-sized footprints.
Summary
In the ensemble of theropod footprints from the Imilchil macrosite,a group of small size separated from the rest is distinguished. We had detected this grouping in other sites studied by our team in La Rioja and in the work of drawing up scatter plots and frequency histograms of the measurements, on a global scale, of the length and width of the theropod footprints (these data are available on request from Farlow. We analyze the particular grouping of small footprints, providing the study of the theropod footprint measurements of 14 new sites with dinosaur footprints in Imilchil and the graphical representation (frequency histograms and scatter plots) of the global data. The work has been done by projecting and comparing the length and width measurements of the Imilchil footprints and the global ones of what we call circumscribed geographical environments (TGC or Temporal Geographical Circumscriptions [cf. Mínguez Ceniceros et al., 2022]). The ichnotaxonomic study of the footprints referred to in this work can be found in Masrour et al., (2023). Finally we interpret the position of maxima and minima in the frequency diagrams, both of Imilchil, and of the other areas in which Farlow has found records (up to the year 2022).
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Ichnological records associated with dermestid beetles in dinosaur bones from Lala’s Place (Maastrichtian), Ramos Arizpe, Coahuila, Mexico, and their taphonomic implications.
Journal of South American Earth Sciences 105110
doi: https://doi.org/10.1016/j.jsames.2024.105110
https://www.sciencedirect.com/science/article/abs/pii/S0895981124003328
Highlights
These fossils belong to the early Maastrichtian period, as determined by U/Pb detrital zircon dating of underlying strata.
Thirteen morphotypes of trace fossils were described on six saurolophine hadrosaur bone elements.
Ichnofossil traces belong to Cuniculichnus seilacheri, cf. Cubiculum cooperi and Cubiculum atsintli
A new ichnospecies, Cubiculum subcorticalis isp. nov., is described, which is a composite feeding-pupation trace with subcortical chambers.
We use the Usefulness in Identification and Differentiation (UID) index to associate the traces to Dermestid beetles.
Abstract
We analyzed the ichnological record of hadrosaur remains from the dinosaur quarry CLP-3, Lala’s Place, Ramos Arizpe, Coahuila, where taphonomic research is ongoing. These fossils have been determined to stratigraphically belong to the Cerro del Pueblo Formation, deposited in a deltaic floodplain environment. The Lala’s Place quarries have been determined to belong to the early Maastrichtian (69 ± 5 Ma) through U/Pb detrital zircon dating. Thirteen trace fossil morphotypes were identified in six bone elements, interpreted to belong to a single individual. These traces were identified to belong to the ichnospecies Cuniculichnus seilacheri, cf. Cubiculum cooperi, Cubiculum atsintli. A new ichnospecies, Cubiculum subcorticalis n. isp., characterized by a composite feeding-pupation trace with subcortical chambers, is also described. Based on these findings, temporal range of the previously described ichnospecies is expanded to the Maastrichtian stage in the Cerro del Pueblo Formation. Previous work has reported these ichnospecies and associated them with dermestid beetles; this work also associates these traces with dermestids through morphological analyses and using for the first time the novel Usefulness in Identification and Differentiation (UID) index, recently proposed for this taxon. These traces indicate that the carcass was exposed to a subaerial environment for at least 20 to 30 days, reaching a dry stage in which dermestid adults fed, reproduced, and oviposited. Larvae produced these traces by excavating chambers to avoid cannibalism by other larvae.
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Liu Xuemin, Lv Xiaowei, Jiang Yao, Shi Zhiqiang, Tian Yaming & Wang Lin (2024)
Deccan volcanism's influence on Chicxulub impact signatures at the continental Cretaceous-Paleogene boundary in the Sichuan Basin, China
Earth and Planetary Science Letters 644: 118932
doi: https://doi.org/10.1016/j.epsl.2024.118932
https://www.sciencedirect.com/science/article/abs/pii/S0012821X24003650
Highlights
This K-Pg boundary preserves evidence of both the impact and Deccan volcanism.
Enrichments in PGE and the black carbon indicate contributions from the impact.
Another PGE anomalies were detected approximately 50 cm below the K-Pg boundary.
PGE anomalies and lithology across this boundary were impacted by Deccan eruptions.
The most voluminous Deccan eruptions occurred following a hiatus after the impact.
Abstract
The Cretaceous-Paleogene (K-Pg) extinction is linked to two primary causes: the Chicxulub asteroid impact in Mexico and the Deccan Traps eruptions in India. While substantial geological evidence supporting both events has been found worldwide, to understand their potential interactions, it is crucial to study sites that preserve records of both events simultaneously. The terrestrial K-Pg boundary located in the Sichuan Basin, China (∼15,500 km from the Chicxulub Crater and ∼5,600 km from the Deccan Traps correspond to 66 Ma), preserves evidence of both the Chicxulub impact and the Deccan Traps eruptions, along with the effects of subsequent events on the earlier ones. It offers a new perspective on the K-Pg boundary. Detailed petrological examination and geochemical analyses, including platinum-group element (PGE) and black carbon concentrations, were conducted across a 2 m K-Pg boundary section. The K-Pg boundary layer (∼2.5 cm thick) is composed of very fine-grained, brick-red sandstone and exhibits significant enrichments in Ir (9.050 ppb) and Os (10.72 ppb), along with elevated black carbon (1.10 ‰), strongly indicating contributions from the impact. Intriguingly, another PGE anomaly was detected approximately 50 cm below the K-Pg boundary. The strata surrounding the K-Pg boundary display evidence of alteration by acidic and HSˉ-rich fluids. These fluids likely caused the observed downward migration of PGE within the boundary, resulting in two distinct PGE anomalies - one at the K-Pg boundary itself and another approximately 50 cm below. These fluids resulted in the overlying sandstones exhibiting minimal matrix content and bleached the underlying brick-red sandstones. Volcanic gas emissions from the Deccan Traps after the impact are a potential source for these fluids. Our findings support the hypothesis that the most voluminous Deccan eruptions had occurred close to, but not necessarily immediately after, the Chicxulub impact, potentially lasting 100–131 ka. The hiatus after the impact weakens the possibility of a direct causal link between the Deccan eruptions and the impact.
Liu Xuemin, Lv Xiaowei, Jiang Yao, Shi Zhiqiang, Tian Yaming & Wang Lin (2024)
Deccan volcanism's influence on Chicxulub impact signatures at the continental Cretaceous-Paleogene boundary in the Sichuan Basin, China
Earth and Planetary Science Letters 644: 118932
doi: https://doi.org/10.1016/j.epsl.2024.118932
https://www.sciencedirect.com/science/article/abs/pii/S0012821X24003650
Highlights
This K-Pg boundary preserves evidence of both the impact and Deccan volcanism.
Enrichments in PGE and the black carbon indicate contributions from the impact.
Another PGE anomalies were detected approximately 50 cm below the K-Pg boundary.
PGE anomalies and lithology across this boundary were impacted by Deccan eruptions.
The most voluminous Deccan eruptions occurred following a hiatus after the impact.
Abstract
The Cretaceous-Paleogene (K-Pg) extinction is linked to two primary causes: the Chicxulub asteroid impact in Mexico and the Deccan Traps eruptions in India. While substantial geological evidence supporting both events has been found worldwide, to understand their potential interactions, it is crucial to study sites that preserve records of both events simultaneously. The terrestrial K-Pg boundary located in the Sichuan Basin, China (∼15,500 km from the Chicxulub Crater and ∼5,600 km from the Deccan Traps correspond to 66 Ma), preserves evidence of both the Chicxulub impact and the Deccan Traps eruptions, along with the effects of subsequent events on the earlier ones. It offers a new perspective on the K-Pg boundary. Detailed petrological examination and geochemical analyses, including platinum-group element (PGE) and black carbon concentrations, were conducted across a 2 m K-Pg boundary section. The K-Pg boundary layer (∼2.5 cm thick) is composed of very fine-grained, brick-red sandstone and exhibits significant enrichments in Ir (9.050 ppb) and Os (10.72 ppb), along with elevated black carbon (1.10 ‰), strongly indicating contributions from the impact. Intriguingly, another PGE anomaly was detected approximately 50 cm below the K-Pg boundary. The strata surrounding the K-Pg boundary display evidence of alteration by acidic and HSˉ-rich fluids. These fluids likely caused the observed downward migration of PGE within the boundary, resulting in two distinct PGE anomalies - one at the K-Pg boundary itself and another approximately 50 cm below. These fluids resulted in the overlying sandstones exhibiting minimal matrix content and bleached the underlying brick-red sandstones. Volcanic gas emissions from the Deccan Traps after the impact are a potential source for these fluids. Our findings support the hypothesis that the most voluminous Deccan eruptions had occurred close to, but not necessarily immediately after, the Chicxulub impact, potentially lasting 100–131 ka. The hiatus after the impact weakens the possibility of a direct causal link between the Deccan eruptions and the impact.
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Free pdf:
Gregory D. Price & Bryan Low Kai Sheng (2024)
Tracking Palaeotemperatures in Coniacian–Maastrichtian Seas
Cretaceous Research 105984
doi: https://doi.org/10.1016/j.cretres.2024.105984
https://www.sciencedirect.com/science/article/pii/S0195667124001575
In this study the stable isotopes of belemnites, are presented from the Coniacian–Maastrichtian interval (∼76–66 Ma) derived from the chalks of Yorkshire and Norfolk, UK, deposited on the western North Atlantic shelf. Cathodoluminescence and elemental geochemistry of the belemnites reveals that most of the rostra were well preserved. If interpreted in terms of temperature, our oxygen isotope record reveals that during the Coniacian (at ∼43 °N) the climate was relatively warm, with maximum mean temperatures of ∼26 °C, followed by cooling to <∼21 °C during the Campanian and Maastrichtian. This overall stratigraphic trend is similar to other records, suggesting that the cooling pattern was not a regional trend and, therefore, driven predominantly by global mechanisms. Within our belemnite data, we also observe a decline in δ13C at the Campanian- Maastrichtian boundary, again consistent with other records. This trend has been interpreted as a result of an increased ratio of organic to inorganic carbon introduced into the oceans, driven by increased weathering and reworking of organic-rich sediments exposed on continental shelves during a sea-level fall. The latter related to a build-up of polar ice. Although our oxygen isotope data point to a cooling this was not necessarily linked to polar ice formation.
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