Indo-Brazilian Late Palaeozoic wildfires: an overview on macroscopic charcoal

Carvão vegetal macroscópico é amplamente aceito como um indicador direto da ocorrência de paleo-incêndios vegetacionais, sendo relativamente bem estudado e distribuído de forma homogênea em depósitos do Paleozoico Superior da Euramérica e Cataísia. Por outro lado, apenas alguns registros deste tipo de material foram publicados para o Paleozoico Superior do Gondwana e, somente recentemente foi demonstrado que carvão vegetal macroscópico (e, portanto, incêndios) também é comum no continente meridional. Os mais importantes registros do Gondwana se constituem em fragmentos carbonizados de lenhos gimnospérmicos e estão associados, principalmente, a depósitos de carvão mineral. Registros de macro-charcoal (carvão vegetal macroscópico) foram descritos para níveis do Paleozoico Superior da Bacia Damodar (Índia) e da Bacia do Paraná (Brasil), demonstrando que paleo-incêndios vegetacionais ocorriam em sequências e intervalos estratigráficos variados no Gondwana durante esse período. Com base nos registros publicados até o momento e em novos exemplares provenientes do nível de carvão Seam-IV, Formação Raniganj, Bacia Damodar (Lopingiano da Índia), uma revisão acerca dos registros indo-brasileiros de carvão vegetal macroscópico em níveis do Paleozoico Superior são apresentados. O material inédito foi analisado sob Microscópio Eletrônico de Varredura para a definição de características anatômicas, sendo estabelecida uma afinidade gimnospérmica para os fragmentos. Os dados apresentados reforçam a importância dos paleo-incêndios vegetacionais como elemento perturbador dos diferentes paleoambientes gondvânicos durante o Paleozoico Superior.Sedimentary charcoal is widely accepted as a direct indicator for the occurrence of paleo-wildfires and, in Upper Paleozoic sediments of Euramerica and Cathaysia, reports on such remains are relatively common and (regionally and stratigraphically) more or less homogeneously distributed. On the contrary, just a few reliable records have been published for the Late Paleozoic of Gondwana and only recently it has been demonstrated that macroscopic charcoals (and thus fires) were also common in the southern continent during this period. The most important Gondwanan records are predominantly charred gymnosperm woods mainly related to coal bearing strata. Late Paleozoic macro-charcoal occurs in both, the Damodar Basin (India) and the Paraná Basin (Brazil), demonstrating that paleo-wildfires were spread out in different sequences and distinct stratigraphic intervals during this period in Gondwana. Based on the so far published records as well as new samples from the Seam-VI coalfield, Raniganj Formation (Damodar Basin – Lopingian of India), an overview of the Late Paleozoic Indo‑Brazilian macro-charcoal remains is presented. The hitherto unpublished samples were anatomically analyzed under Scanning Electron Microscope and a gymnosperm affinity could be established. The data presented here reinforce the relevance of paleo-wildfire as a source of environmental disturbance over large areas of Gondwana during the Late Paleozoic

The South Shetland Islands, Antarctica: unified lithostratigraphy and geological map

Over the last few decades, numerous geological studies have been carried out in the South Shetland Islands, which have greatly contributed to a better understanding of its geological evolution. However, few attempts have been conducted to correlate the geological units throughout this archipelago. We present herein a lithostratigraphical correlation, which constitutes a coherent and unified stratigraphy for the main Mesozoic and Cenozoic units rocks of the South Shetland Islands along with a new geological map. The lithostratigraphical correlation shows that the geological evolution comprises three main stages: (i) deep marine sedimentation from ~164 to 140 Ma, (ii) subaerial volcanism and sedimentation with a proliferation of plants and fauna from ~140 to 35 Ma and (iii) glacial and interglacial deposits from ~35 Ma. The lithostratigraphical correlation also shows a broad geographical trend of decreasing age of volcanism from southwest to northeast, which has been previously suggested. However, this spatial age trend is disrupted by the presence of Eocene magmatism in Livingston Island, located in the centre of the archipelago. We suggest that the migration of volcanism occurred from the Late Cretaceous until the early Eocene. Subsequently, enhanced magmatic activity took place from the mid-Eocene until the Miocene, which we associate with processes related with the waning of subduction, such as roll-back. Finally, constraining the protolith age of the metamorphic complex of Smith Island remains challenging, yet holds key implications for the tectonic and accretionary evolution of the Antarctic Peninsula. The rocks recording the glaciation of this sector of Antarctica are well exposed in the northern South Shetland Islands and hold critical information for understanding the timings and processes that lead to the greenhouse-icehouse transition towards the Eocene end. Contemporaneous rocks to the breakup of Antarctic Peninsula from Patagonia, which led to the Drake Passage opening and the development of the Scotia Sea, are exposed in the north-centre of the archipelago. A better age constrain of these units may lead to further understanding the paleontological evolution of this region. The dataset containing the geological map is shared as a shapefile and KML file

The first report of a Campanian palaeo-wildfire in the West Antarctic Peninsula

The analysis of palaeofloras and the related palaeoecological conditions is of great importance for the understanding of past environmental and palaeoclimatic events in Antarctica. At the end of the Cretaceous, subtropical forests developed there because of wet and temperate climate conditions. On the Antarctic Peninsula, which is geologically characterized by a forearc context, volcanic activity caused by tectonics favours the ignition of vegetation fires. In the present study, the occurrence of palaeo-wildfires during the Upper Cretaceous is demonstrated for the Rip Point outcrop on Nelson Island, South Shetland Islands. During Brazilian expeditions to the area, macroscopic charcoalwas collected and subsequently analysed under a stereomicroscope and scanning electron microscope (SEM). The charred wood remains were identified as belonging to conifers, which were important components of the Antarctic palaeoflora during the Cretaceous. A reviewof the data published thus far regarding palaeo-wildfires in the Southern Hemisphere confirms that the charcoal remains analysed here are the first to verify the occurrence of palaeo-wildfires in the upper Campanian levels of the West Antarctic Peninsula.Fil: Manfroi, Joseline. Universidade do Vale do Rio dos Sinos; Brasil. Centro Universitário UNIVATES; BrasilFil: Lindner Dutra, Tânia. Universidade do Vale do Rio dos Sinos; BrasilFil: Gnaedinger, Silvia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Nordeste. Centro de Ecologia Aplicada del Litoral (i); ArgentinaFil: Uhl, Dieter. Centro Universitário UNIVATES; Brasil. Senckenberg Forschungsinstitut und Naturmuseum; Alemania. Universität Tübingen; AlemaniaFil: Jasper, André. Centro Universitário UNIVATES; Brasi

Hepaticites iporangae Ricardi-Branco, Faria, Jasper, and Guerra-Sommer, 2011 from the early Permian of the Paraná Basin, Brazil, is not a liverwort but a tracheophyte

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)From new and more complete material, which includes frond fragments with casts of tracheid remains of the rachis, it can be demonstrated that the putative liverwort Hepaticites iporangae Ricardi-Branco, Faria, Jasper, and Guerra-Sommer, 2011, from the early Permian Rio Bonito Formation (Sakmarian) of the Parana Basin, Brazil, is not a bryophyte but a tracheophyte. The new material was collected from the same locality and layer as the type material, in the Quiteria outcrop in the municipality of Encruzilhada do Sul, state of Rio Grande do Sul, Brazil. From the morphology of the deeply dissected pinnatifid pinnules with narrow laminar lobes, the taxon is provisionally reassigned to the genus Rhodeopteridium. Thus we propose the new combination 'Rhodeopteridium' iporangae new combination for this taxon. This new systematic interpretation contributes to our understanding of early liverworts (by removing Hepaticites iporangae as a possible taxon thereof) and clarifies an issue of diversity of the flora of the early Permian Rio Bonito Formation resulting from the original misidentification.From new and more complete material, which includes frond fragments with casts of tracheid remains of the rachis, it can be demonstrated that the putative liverwort Hepaticites iporangae Ricardi-Branco, Faria, Jasper, and Guerra-Sommer, 2011, from the ear904632639FAPERGS - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DO RIO GRANDE DO SULCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)sem informaçãosem informaçãosem informaçã

Data from: A unique Late Cretaceous fossil wood assemblage from Chilean Patagonia provides clues to high-latitude continental environment

<p>Fossil plants, including large trunks, stems, some branches, and twigs, were collected from the Maastrichtian (68.9 Mya), upper Dorotea Formation in the Magallanes/Austral Basin, 16 km north of the Cerro Guido-Las Chinas complex in the southern Chilean Magallanes region. These fossil trunks range from 0.2 m to 2.2 m in length. Petrographic slides were made in three sections (transverse, radial, and tangential) and analysed under a light microscope to study the permineralised fossils. The woods and stems belong to Austroginkgoxylon gen. et sp. nov., Agathoxylon antarcticum, Podocarpoxylon paradoxi sp. nov., Podocarpoxylon mazzonii, Palmoxylon subantarcticae, and Nothomalvaceoxylon magallanense gen.et sp. nov. The growth rings of gymnosperms and anatomical characters of angiosperms were analysed to obtain palaeoecological data. Interactions between gymnosperm roots growing into the secondary xylem of an angiosperm (nurse logs) are recorded. The data obtained from the fossil woods suggest warm and humid conditions in this southern South American locality during the Late Cretaceous, providing a unique opportunity to study continental environments at high southern latitudes, which are poorly represented on a global scale.</p><p class="MsoNormal"><span>Libre Office. Version: 7.3.6.2 (x64) / LibreOffice Community</span></p> <p class="MsoNormal"><span>Past 4.03. Paleontological stadistics software for education and data analysis.</span></p><p>Funding provided by: Agencia Nacional de Investigación y Desarrollo<br>Crossref Funder Registry ID: https://ror.org/02ap3w078<br>Award Number: 1151389</p><p>Funding provided by: Agencia Nacional de Promoción Científica y Tecnológica, Argentina*<br>Crossref Funder Registry ID: <br>Award Number: PICT-2019-03749</p><p>The fossil woods described here are based on observations of 12 logs of silicified woods and stems collected from 16 km to the north of the Cerro Guido locality, Magallanes region, southern Chile (Fig. 1). Observations and descriptions of the slides were carried out with light microscopic (LM). Slides of the cross (CS), radial (RS), and tangential (TS) wood sections were prepared for observation using a Nikon light microscope. The terminology used follows, in general, the IAWA list of microscopic features (IAWA 2004, 1989). Cell dimensions are based on a minimum of 25 measurements, and the numbers in brackets indicate the minimum and maximum values. </p> <p>Two indices were used to quantify the intertracheary pitting:  the 'Contiguity percentage index (Cp) and Seriation index (Si)' of Pujana <em>et al.</em> (2016). Values of Si equal to or close to 1.00 indicate that all the intertracheary pits are uniseriate, while values of Si >1.00 indicate two or more seriate pits. Values of Cp equal to or close to 0% indicate that pits are non-contiguous, and values of Cp close to 100% indicate that all pits are contiguous.</p&gt