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Integration of late Quaternary continental and marine proxies allows improved reconstruction of palaeoenvironment and palaeoclimates models for the south-eastern coast of Brazil. In this paper, we analyse pollen, fern spores, and dinoflagellate cysts in a marine sediment core (GL74) over the last ∼109 kyr. Results showed that, between 109 and 89.5 kyr, low sea levels promoted the expansion of herbaceous taxa across open areas while climatic conditions were relatively warm and humid, as indicated by the high frequency of Atlantic rainforest Ombrophilous forest pollen types and abundant of fern spores. Between ∼79–49 kyr, higher concentrations of palynomorphs were recorded, which were likely related to the low relative sea level during the last glacial period. During this interval, there was a decrease in tree pollen grains and an increase in shrub and herbaceous pollen grains, indicating cold and relatively dry weather conditions. In the Holocene period, the low deposition of palynomorphs may have been influenced by the gradual submergence of the central part of the Brazilian coast. This process was associated with warm and humid climatic conditions, as suggested by the expansion of rainforests and the presence of hygrophyte/aquatic taxa and fern spores, as well as the retraction of grassland pollen types. Dinocyst assemblages suggest that nutrient-rich waters and/or the presence of upwelling cells were dominant between ∼109–88 kyr, but gradually reduced between 88 and 65 kyr (and/or ∼ 88–20 kyr) under the influence of subtropical fronts. The study culminated in the dominance of unproductive warm water in the upper column between 65 and 0.5 kyr. • Correlation of continental and marine proxies in south-eastern Brazil during the late Quaternary Late • Quaternary dynamics of the South Atlantic Ocean based on dinocysts • Reconstruction of palaeovegetation and palaeoclimate for the last ∼109 kyr along the southeast coast of Brazil [ABSTRACT FROM AUTHOR]

A rich insect fauna is found in the Cretaceous (Aptian) Nova Olinda Member of the Crato Formation in the Araripe Basin, northeastern Brazil. The Crato Formation was deposited close to the centre of the supercontinent Gondwana, prior to significant rifting. In this paper, we analyzed remains of 1135 insect specimens, representing 55 families, within two limestone facies of the Nova Olinda Member: pale yellow and dark gray limestones. We collected taphonomical data and assessed the paleoecological significance of insect faunas in terms of their distribution and interaction with the paleoenvironment. The insect fauna is dominanted by fully terrestrial taxa despite preservation in an aquatic paleoenvironment. Considering both facies, the distribution of insect families is similar throughout the Nova Olinda Member, which excludes possible overlapping of one entomofauna over another. The pale yellow limestones near the top of the section are richer in fossil insect content and show a higher incidence of aquatic and semiaquatic insects preserved in dorsoventral view compared to the dark gray limestones. This suggests that the Crato insects preserved in the pale yellow limestones experienced short transport distances or prolonged decay or both. In contrast, insects preserved in the dark gray limestones appear proportionally with higher degrees of disarticulation than those preserved in the pale yellow limestones, indicating that these insects underwent a higher degree of postmortem transport in the biostratinomic stage. Compared to descriptions of other Early Cretaceous assemblages, the taxonomic literature of Crato Paleoentomofauna shows distinct differences. The Yixian and Zaza formations are described as being dominated by beetles and wasps. The Crato Formation, however, is relatively richer in Paleoptera species. Both the sedimentary facies studied and the paleoentomological content reveal a complex ecosystem inserted in a depositional setting, similar to modern long-standing wetlands, and where periodically flooded zones were surrounded by dry lands with xeromorphic vegetation. • Crato insects preserved in the dark gray limestones appear proportionally with higher degrees of disarticulation. • The paleoentomological content reveals an ecosystem inserted in a setting similar to modern long-standing wetlands. • Compared to other Early Cretaceous assemblages, the Crato Paleoentomofauna is relatively richer in Paleoptera species. [ABSTRACT FROM AUTHOR]

Paleosols are an under-utilized tool for paleoenvironmental and paleoclimatic reconstruction in Brazilian intracontinental basins. The Itapecuru Formation, from the Lower Cretaceous of the Parnaíba Basin, consists of a 600-m-thick succession of interbedded very fine-to-fine-grained sandstone, mudstone, and paleosols containing rich fossil assemblages. This paper provides a detailed description of the macro and microscopic pedogenic features of a hydromorphic paleosol profile whithin the Itapecuru Formation. Analyses of clay mineralogy and whole-rock geochemistry in the hydromorphic paleosols at the Prata locality are used to infer pedogenic processes, paleoclimate, paleohumidity and paleovegetation. Estimates of paleoprecipitation and paleotemperature using climofunctions, chemical index of alteration without potassium, and paleosol weathering index proxies (PWIs) show values ranging from 810 to 1042 mm/yr (SE = ±78.1 mm/yr) and 10.9 to 11.8 °C (SE = ±0.23 °C), respectively. Climofunction values (MAP and MAT), paleohumidity, Kӧppen aridity index, and pedogenic clay mineral content suggest a humid paleoclimate during soil-forming and weathering processes. Based on these climate data and previously published paleogeographic and palynological studies, the Cretaceous (Albian) Prata pedotype was formed within the equatorial humid belt with vegetation of wet tropical forests. • Alluvial paleosols are characterized in the Parnaíba Basin. • Based on mineralogy and geochemistry analysis, six pedogenic processes were recognized along the Prata pedotype. • Climofunctions values suggest a humid paleoclimate during paleopedogenic modification. • The Albian paleolatitude of Brazil, along with studied climate data, suggests the influence of the Equatorial Humid Belt. • The soil taxonomy following paleoclimate data and pedogenic processes define the Prata pedotype as Ultisol Aquults. [ABSTRACT FROM AUTHOR]

In this paper, we use palynology and geochemical proxies to reconstruct late Quaternary vegetation changes within the hydrographic basin of Parnaíba, Northeast Brazil, over the last 130 kyrs. Findings are based on the analysis of a marine sediment core (GL-1248) retrieved from the western equatorial Atlantic (0°55.2′S, 43°24.1′W), close to the coast. Geochemical proxies (Fe/K ratio and Ɛ Nd) indicative of soil erosion match changes in reconstructed vegetation, suggesting a dynamic pattern of hydrological disturbances and ecosystem evolution. Given that reconstructed vegetation does not present the same response to precipitation anomalies on the millennial scale, we sought the main drivers of vegetation changes in the Parnaíba watershed. Results indicate that vegetation succession was primarily influenced by austral insolation from March to May, which triggered changes in the pioneer vegetation types. Our study improves the knowledge of tropical vegetation dynamics in an orbital framework, suggesting 23-kyr precessional cycles as the main driver of landscape evolution in Northeast (NE) Brazil. We also infer that such past climate change events may have been a key causal factor of the high biodiversity of the Neotropics, mediated through the biological exchange of the Amazon and Atlantic rainforest species via ecological forest corridors in the semi-arid Northeast Brazil. • We discuss vegetation change and how it reflects hydrological changes within the Parnaíba Basin, northeastern (NE) Brazil, over the past 130 kyrs • Geochemical proxies (Fe/K ratio and ƐNd) in core GL-1248 are synchronous with reconstructed vegetation patterns, highlighting periods of enhanced or reduced local soil erosion during hydrological disturbances • We define three major vegetation groups (tropical dry forest, lowland rainforest, and wetland), and the discrepancy in water requirements between tropical dry forests and lowland rainforests is discussed • Analysis of the hydroclimatic mechanisms in NE Brazil that triggered the succession of vegetation during glacial phases is discussed [ABSTRACT FROM AUTHOR]

Burrowing behavior is an important adaptation of animals that live in arid and semi-arid conditions. In this paper, we describe examples of vertebrate burrows from the Upper Cretaceous (Maastrichtian) Adamantina Formation of the Bauru Basin, Brazil, most likely produced by turtles. The Adamantina Formation preserves abundant and diverse turtle body fossils such as Bauruemys elegans (Testudines: Pleurodira); however turtle burrows have not been previously documented. The newly reported burrows are preserved in fluvial sandstone facies and exposed in sections that partially preserve their three-dimensional geometry. Burrows are simple J-shaped tunnels with a cross-sectional shape that is semicircular (half-dome) with a flattened floor. Such burrows show a partially preserved entrance with an inclined ramp angle (22°), and grooves and ridges up to 1 cm in width preserved along the burrows walls and floor. The architecture and sedimentary facies of the host sandstone body, together with the occurrence of Taenidium barretti and the absence of rhizoliths, suggest that the burrow was excavated by scratch digging into an exposed point bar of a meandering river channel. Based on burrow morphology, dimensions, as well as ridges,and grooves in the walls and floor, we propose that burrows were formed by a chelonian (such as a freshwater turtle) during aestivation. We highlight that these are first examples of turtle burrows reported from the Cretaceous, and their occurrence reinforces the hypothesis that the original function of turtle shells was as an adaptation to fossorial behavior. [Display omitted] • The first freshwater turtle burrows from Cretaceous of South America. • The burrows occur in fluvial point bars of Adamantina Formation. • Evidence of fossorial and aestivation behavior in turtles during Cretaceous. • Results reinforce the hypothesis of fossorial behavior in stem turtles. [ABSTRACT FROM AUTHOR]

Drowning unconformities are surfaces characterized on seismic data by high amplitude contrast between deepwater and shallow water facies. Such surfaces are created by the covering of the platform by onlapping siliciclastic sediments or other non-platform material. The key aspect of this paper is the application of the drowning unconformity concept, commonly used in marine settings, to a more restrictive one: the coquinas of the Itapema Formation, in the pre-salt succession of the Santos Basin (Brazil). In the studied area the sequence boundaries of the deposits related to the Itapema Formation are often associated with high reflectivity seismic horizons, which are tied to radioactive peaks of low-energy sedimentary facies in the gamma ray logs and also to the siliciclastic supply rate increase. However, the stratigraphic significance of these reflectors still lacks further investigation and an adequate description. In this way, it is proposed that the space-time filling of the Itapema Formation occurred by the successive migration of proximal facies towards the structural highs, under continuous accommodation space generation conditions and high carbonate production rate, with the depocenters limited by rapid expansions of the basin. The results presented here, therefore, suggest that the sedimentary record of this section was punctuated by instantaneous transgressive surfaces that altered the ecological accommodation, forcing the backstepping of the coquina deposits and the development of a drowning unconformity in the final stage of the Itapema Formation deposition. This configuration produced at the top of this unit a specific facies association characterized by packstones and mudstones composed of micritized grains, which increase in volume and thickness towards the structural lows and tend to be thinner on the way up to the structural highs, where they may be eroded by the Pre-Alagoas Unconformity. The correct identification of such surfaces is essential for understanding the sedimentary filling of the studied area. Depending on which surface is mapped, they may be related to different processes and occur in opposite positions in the base-level cycles. Thus, we propose the existence of two surfaces at the end of the deposition of the Itapema Formation. The first limits the top of the coquinas and is represented by the contrast of low-energy sediments (packstones and micritized mudstones) and the coquinas deposits, configuring the platform drowning itself. The second one, in turn, is understood here as the Pre-Alagoas Unconformity, a subaerial unconformity associated with the regional platform exposure, developed after the drowning events recognized here. • Seismic and well characterization of drowning unconformities in the pre-salt succession. • Drowning unconformities in a non-marine environment setting. • Shut-down of the coquina factory associated with a rapid drowning in early Cretaceous. [ABSTRACT FROM AUTHOR]