Notes on Devonian chitinozoan biozones of Western Gondwana
Camina, S. C.1* and Butcher, A.2
1IANIGLA-CCT CONIaCET, Av. Ruiz Leal s/n, Parque General San Martín, 5500 Mendoza, Argentina; 2School of Environment, Geography and Geosciences, University of Portsmouth, Portsmouth, PO1 3QL, UK.
*Corresponding author: scamina@mendoza-conicet.gob.ar
Chitinozoans have been crucial for Devonian biostratigraphy, leading to a global biozonation by Paris and colleagues twenty-five years ago. This biozonation was considered provisional due to the limited study of Devonian chitinozoans compared to Silurian and Ordovician ones. Five years later, Grahn proposed a formal biozonation for Western Gondwana. However, despite new findings, no revisions have been made in the past two decades. Until a formal revision is conducted, this contribution aims to provide notes and updates on some of these biozones. Thirteen Western Gondwana biozones were initially proposed based on the first occurrence (FO) of key chitinozoan species. The early Lochkovian biozone is defined by the FO of Angochitina praedensibaculata. This species should be re-evaluated, as the only distinguishing feature from Sphaerochitina densibaculata is the length of the spines, suggesting they may be the same species. Urochitina loboi is the proposed biozone for the late Lochkovian. Although Urochitina species are common during this period, the fragility of the diagnostic peduncle can make them difficult to recognise. Cingulochitina species, are extremely common alongside Ancyrochitina asterigis in the late Lochkovian and may be useful additions to this biozone. Ancyrochitina parisi defines the biozone for the late Emsian. Initially thought to be restricted to this period, recent findings indicate a peak of abundance in the early-middle Givetian in Western Gondwana. Since the FO of this species is in the late Emsian, additional diagnostic species should be included in this biozone. The early-middle Givetian biozones should be revised to include species such as Ramochitina ramosi, Fungochitina pilosa, and Ancyrochitina cornigera, which have proven to be very useful for local biozonations. In general, a detailed revision is needed due to taxonomic and stratigraphic changes in some species. This will enhance the usefulness of chitinozoans as a biostratigraphic tool for the Devonian.
An integrated palynological analysis of the Quaternary-Oligocene sucession in the northern Viking Graben, North Sea
Henderson, C. A. B.1
1Henderson Stratigraphic Ltd., Labstrat, Founder & Geoscience Subcontractor, 35 Gillfoot Road, Egremont, Cumbria, CA22 2QD, UK.
Corresponding author: Cameron.henderson@labstrat.com
This study integrates palynological and micropalaeontological analyses to enhance the understanding of Quaternary-Oligocene stratigraphy across three wells (33/9-11, 34/7-7, and 34/8-1) in the northern Viking Graben, North Sea. The analysis of 221 palynomorph species (134 dinoflagellates, 69 spores and pollen, and 14 algal cysts) alongside diverse microfossils (e.g., foraminifera, diatoms, and radiolaria) identified 40 fossil events (31 palynomorph and 9 microfossil). These findings enabled detailed biozone correlations, even without core material for independent age control.
Key contributions include the identification of novel palynomorph events—such as distinctive acmes and peaks—that refine regional biostratigraphic zonation with enhanced resolution, compared to other disciplines. These advancements have significant applications for geological models supporting industrial projects, including E&P (Exploration and Production) and CCUS (Carbon Capture, Utilisation, and Storage), as exemplified by the 2008 Tordis IOR (Increased Oil Recovery) case.
This study underscores the critical role of biostratigraphy, particularly palynology, in subsurface site and complex characterisation. Future research should prioritise high-resolution sampling of core material across the northern North Sea to improve first-order age control, refine stratigraphic frameworks, and address potentially diachronous fossil events.
Digital Palynology
Jaramillo C.
Smithsonian Tropical Research Institute
Corresponding author: jaramilloc@si.edu
The study of pollen and spores started more than a century ago and provides the fundamental basis to understand vegetation changes through time, date sedimentary rocks through biostratigraphy, and model plant evolution among many other applications. Since its origin, palynology has relied on the manual count of pollen and spores using a microscope. This is a process that requires a long time, and years of training, and produces data that is not fully reproducible. The advent of new robotic tools that can digitize complete microscope slides and the fast development of neural network algorithms have provided the timing for Palynology to enter a new era in data generation and analysis. We are developing a training set of neotropical pollen to be used in a neural network that will assist in pollen counts and identification. The developments produced here could be applied to multiple research questions where pollen can be used from paleoecology and paleoclimate, oil, gas, and coal exploration, hydrogeology, and allergology to pollination biology and honey production.
Palynofloras from volcanic seaward dipping reflector sequences: IODP Expedition 396, Voring and More Basins, Norway
Jolley, David1* & Vieira, Manuel2,3
1Department of Geology & Geophysics, School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, Scotland. 2GeoBioTec ‐ polo FCT, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus da Caparica, 2829‐516 Caparica. 3Aker BP ASA, Oksenøyveien 10, 1366 Lysaker, Oslo, Norway
*Corresponding author: d.jolley@abdn.ac.uk
The opening of the North Atlantic about 56 My ago was associated with the emplacement of the North Atlantic Igneous Province, including the deposition of widespread extrusive basaltic successions and intrusion of magma into the surrounding sedimentary basins. Volcanic succession on the mid-Norwegian Margin hosts have been targeted by scientific drilling since the 1970’s. More recently, International Ocean Discovery Program Expedition 396, drilled a series of sites in the More and Voring basins in 2022. These penetrated lava flow fields and intrusive igneous bodies and thick successions of Paleogene sedimentary rocks. Here, we focus on the stratigraphy and depositional environment of the inter lava sediments drilled by Leg 396. These are associated with large scale seaward dipping reflector complexes (SDR), which form the seward extension of lava fields erupted on the basin margin. All of the drilled holes yielded inter volcanic palynofloras from environments which ranged from wholly terrestrial to marine shelf. Analysis of the microplankton and pollen floras established the wide range of depositional environments represented within SDR packages. Both the microplankton and pollen recovered are characteristic of the latest Thanetian and Ypresian. These palynofloras have constrained the age and stratigraphical relationships of the volcanic, volcaniclastic and siliciclastic rock units, providing insight into the progressive rifting of the NE Atlantic.
The Choteč Event in Northern Spain: Exploring an island in the Rheic Ocean during the Early-Mid Devonian transition
Lopes, G.1,2*, Blanco-Ferrera, S.3, Bodman, D.4, Bond, D.P.G.5, Greene, S.6, Hilton, J.6, Marshall, J.7, Sanz-López, J.3, Wellman, C.1
1School of Biosciences, University of Sheffield, UK. 2CIMA, University of Algarve, Portugal. 3Department of Geology, University of Oviedo, Spain. 4MB Stratigraphy, UK. 5School of Environmental Sciences, University of Hull, UK. 6School of Geography- Earth and Environmental Sciences, University of Birmingham, UK. 7University of Southampton, School of Ocean and Earth Science, Southampton, United Kingdom.
*Corresponding author: g.m.lopes@sheffield.ac.uk
During the Devonian Period, the Armorican Terrane Assemblage comprised isolated basement blocks between the supercontinents of Laurussia and Gondwana. In northern Spain, particularly Asturias and León, extensive Devonian sequences were deposited on and around these islands. At the transition from the Emsian to the Eifelian stages, a notable facies change occurred, with carbonate sequences of the Moniello Formation in Asturias and the equivalent Santa Lucía Formation in León shifting rapidly to the sandstones and shales of the Naranco Formation and Huergas Formation. This transition is linked to the Basal Choteč Event, a global anoxic pulse. This work presents geochemical data and rare palynological assemblages from the carbonate deposits of the Moniello and Santa Lucía formations and the transitional beds with the Naranco and Huergas formations.
The geochemical analysis reveals that a negative carbon isotope excursion, proxies showing increased weathering, and a brief rise in productivity and anoxia characterize the Basal Choteč Event. The palynological assemblages, independently dated using conodonts and brachiopods, include marine elements (acritarchs, prasinophycean cysts, chitinozoans, scolecodonts) and terrestrial spores, which are unexpectedly common in certain levels. Overall, the assemblages appear impoverished and show moderate to high endemism, likely due to isolation. A key question is whether these changes in these assemblages during the Choteč Event were related to environmental shifts or represent an extinction event?
Archaeoperisaccus indistinctus as a key indicator of Devonian palaeogeography
Marshall J.1*, Berry, C. M.2, Blanco Ferrera, S.3, Bodman, D.4, Bond, D.5, Green, S.6, Hilton, J.6, Liu, F7., Lopes, G.8, Sanz López, J.3, Tel’nova, O.9 Wang, Y.7, Zhu, H.7, Wellman, C.H.8
1School of Ocean and Earth Science, University of Southampton, UK; 2School of Earth and Ocean Science, University of Cardiff, Wales, UK; 3Department of Geology, University of Oviedo, Spain; 4MB Stratigraphy, UK; 5Department of Geography, Geology and Environment, University of Hull, UK; 6School of Geography, Earth and Environmental Sciences, University of Birmingham, UK; 7NIGPAS, Nanjing, China; 8Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, UK 9Institute of Geology, Komi Scientific Center, Syktyvkar, Russia
*Corresponding author: jeam@soton.ac.uk
Archaeoperisaccus is a distinctive Devonian monolete spore notable for being found only in the Frasnian (Early Late Devonian) of northern Laurasia with additional scattered records from Gondwana, generally being discounted. This unity of the biogeographic and stratigraphic distribution of Archaeoperisaccus was questioned by its discovery in the Givetian of Yunnan, China with similar spores reported from Australia as a new species, A. rhacodes that is a junior synonym. This southern hemisphere Archaeoperisaccus (as A. indistinctus) species differs in possessing a ‘camerate’ structure with scattered small processes that is more similar to Grandispora whereas the ‘northern’ Laurasian forms generally have more in common with Cristatisporites. It also differs in its TEM ultrastructure.
Importantly, we have discovered many specimens of unequivocal A. indistinctus from several samples within a 200 m thick section of Frasnian age from Ymer Ø, East Greenland. This is palaeogeographically within the interior of the ORS continent. These forms are, as yet, unknown within European Russia. We have also discovered many specimens of A. indistinctus from the Givetian of northern Spain which, in the Mid Devonian, was positioned on the northern margin of Gondwana. These findings highlight likely palaeogeographic routes for the migration of the plant bearing this spore from the area of Australia/China together with barriers that prevented its global migration.
Age assignment and correlations based on Permo-Triassic sequences from Maniamba Basin, Mozambique (Central Gondwana)
Nhamutole, N1,2*, Bamford, M.K1, Souza, P. A3, Félix, C.M3, Carmo, D.A4, Peu, J5
1Evolutionary Studies Institute and School of Geosciences, University of the Witwatersrand, P Bag 3, Wits, 2050, Johannesburg, South Africa; 2Ministry of Mineral Resources and Energy, Maputo, Mozambique; 3Laboratório de Palinologia Marleni Marques Toigo, Instituto de Geociências, UFRGS, Brazil; 4Laboratório de Micropaleontologia da Universidade de Brasília, Brasília, DF, Brazil; 5Eduardo Mondlane University, Departamento de Geologia, Av. Moçambique, Km 1.2, Maputo, Moçambique.
*Corresponding author: 2275773@students.wits.ac.za
In the present work, dark siltstones, claystones, shales, coals and carbonaceous shale were critically investigated to identify palynofloral assemblages in Mozambiqueʼs overlooked Karoo-aged Maniamba Basin. The study was based on two borehole cores. It unveiled a rich and diversified microflora composed of four distinct palynoassemblages dominated by striate and non-striate bisaccate pollen grains that have prevailed under humid, warm and arid climate conditions in these Gondwana strata. The lower palynoassemblages 1 (P1) and 2 (P2) in both borehole cores are marked by the occurrence of common and abundant striate and non-striate bisaccate pollen, Protohaploxypinus spp., Protohaploxypinus limpidus, Striatopodocarpites cancellatus, Lueckisporites spp., Scheuringipollenites spp and colpate Cycadopites cymbatus. Late Permian key taxa such as Marsupipollenites triradiatus, Plicatipollenites gondwanensis, and Guttulapollenites hannonicus are found herein. The palynoassemblages 3 (P3) and 4 (P4), were assigned to the Early Triassic based on the FAD of key taxa, chiefly Platysaccus papilonis, Lunatisporites spp., Lundbladispora sp. and Krauselisporites sp. A younger age is assigned to the K5 Formation in the Maniamba Basin correlating well-known Gondwana sequences from the Katberg and Balfour formations from the Main Karoo Basin (South Africa), the Moatize-Minjova Basin (Mozambique), Sakamena Group (Madagascar), Raniganj-Panchet formations (India), Mid-Zambezi valley (Zambia), and the Salt Range Basin (Pakistan). Fossil wood occurrences support the assigned ages. Although other proxies are needed to identify the Permo-Triassic transition, the obtained new palynological data could spark interest in exploring methane associated with coal beds.
Disentangling the taxonomic affinity of Late Miocene Polylepis/Acaena (Rosaceae) pollen grains from the coastal Peruvian Desert
Ochoa, D.1,2*, Adaime, M-E.3 , Orosco, B. 2,4, Montenegro, F. 2, and Romero, I.4,5
1 Departamento de Geología, Universidad de Salamanca, Salamanca, 37008, España; 2 Centro de Investigación para el Desarrollo Integral y Sostenible (CIDIS), Universidad Peruana Cayetano Heredia, Lima, Peru; 3 Data Science Lab, Smithsonian Institution, Washington, DC, 20560; 4 Center for Tropical Paleontology and Archaeology, Smithsonian Tropical Research Institute, Panama; 5 Department of Paleobiology, Smithsonian National Museum of Natural History, Washington, DC, 20560
*Corresponding author: diana.ochoa@usal.es
Polylepis and Acaena, two genera within the Sanguisorbae tribe of the Rosaceae family, demonstrate distinct evolutionary and ecological trajectories. Diverging during the Middle to Late Miocene, these genera now occupy markedly different climatic niches, growth forms, and ecological roles. Acaena, a low-growing herbaceous plant or small shrub, is characterized by spiny leaves and bur-like fruits. It thrives in open grasslands and disturbed habitats, displaying remarkable resilience to grazing and trampling. This genus is widely distributed across the Southern Hemisphere, including New Zealand, Australia, and South America. In contrast, Polylepis comprises woody shrubs and trees confined to high-altitude Andean ecosystems, where they form some of the world’s highest-elevation woodlands. Adapted to extreme UV radiation, cold temperatures, and arid conditions, Polylepis plays a vital role in sustaining Andean biodiversity.
The South American pre-Quaternary paleontological record for Polylepis and Acaena is limited, consisting primarily of pollen fossils and a few macrofloral remains from regions including the Descanso-Yaurí Basin (Mio-Pliocene; Descanso Formation), the Amazon Basin (Miocene, Pebas Formation), the Austral Basin (Oligocene; Rio Guillermo Formation), and Tierra del Fuego (Oligocene; Cullen Formation). Unfortunately, under light microscopy, the existing pollen grains are often morphologically indistinguishable.
This study aims to apply light microscopy imaging and deep learning algorithms to analyze the morphology of well-preserved Middle and Late Miocene (12 and 8 Ma) pollen grains from the Peruvian Desert. Comparisons will be made with a newly established reference collection of modern neotropical Sanguisorbae pollen, spanning seven genera. By establishing robust taxonomic affinities for these fossil grains, we aim to reconstruct Miocene landscapes in coastal Peru and infer past ecological preferences and climatic niches of Polylepis and Acaena.
Interglacial vegetation changes in Central India: A snapshot at Marine Isotope Stage 11
Oliveira, D.1,2, Desprat, S.3, 4, Yin, Q.5, Zorzi, C.1,2, Wu, Z.5, Anupama, K.6, Prasad, S.6, Alonso-García, M.7, Martinez, P.3
1 Centre of Marine Sciences (CCMAR/CIMAR LA), Universidade do Algarve, 8005-139 Faro, Portugal; 2 Instituto Português do Mar e da Atmosfera (IPMA), 1495-165 Algés, Portugal; 3 Université de Bordeaux, CNRS, Bordeaux INP, UMR 5805 EPOC, F-33600 Pessac, France; 4 Ecole Pratique des Hautes Etudes (EPHE), PSL University, Paris, France; 5 Earth and Climate Research Center, Earth and Life Institute, Université Catholique de Louvain, Louvain-la-Neuve, Belgium; 6 Laboratory of Palynology and Paleoecology, Department of Ecology, French Institute of Pondicherry (IFP), UAR 3330, CNRS-MAEE, Pondicherry 605001, India; 7 Faculty of Sciences, Department of Geology (Paleontology), Universidad de Salamanca, Pza de los Caídos, 37008 Salamanca, Spain
*Corresponding author: dulce.oliveira@ipma.pt
The Indian Summer Monsoon (ISM) is the dominant Asian monsoon subsystem concerning energy flux, being considered one of the Earth’s strongest hydrological regimes. It brings up to 90% of the annual rainfall into the Core Monsoon Zone (CMZ), where the ISM has its most representative expression. Alarmingly, the uncertainty in ISM precipitation projections is still high due to the complexity of simulating its various interconnections. ISM records of past interglacials, warm periods as the Holocene, are thus critical to understand the main drivers of the ISM natural variability.
This study focus, for the first time, on the Indian monsoon-induced vegetation change during MIS 11 (425-374 ka), an important analogue of the Holocene owing to its similar astronomical configurations, higher than present-day sea level and CO2-driven climate warming. Pollen analysis at Site U1446, strategically retrieved from the CMZ, show a first major forest phase during MIS 11c followed by two forest phases separated by open vegetation periods indicating a shift to drier conditions due to reduced ISM. The forest's maximum development occurs during the highest insolation level of MIS 11c which reveals the dominant influence of this forcing on the ISM hydroclimate under interglacial conditions, i.e., relatively high sea-level and CO2. However, during the second part of MIS 11 we suggest that insolation forcing is dwarfed by the influence of increasingly larger ice-sheets and lower CO2. Our results highlight, therefore, the complex interplay between the forcings in driving hydroclimate and vegetation change under the distinct boundary conditions of interglacial MIS 11.
Palynological Characterization of a seasonal desertic ecosystem: The Peruvian Lomas.
Tejada-Fajardo, A.1*, Montenegro, J. F.1 and Ochoa, D.1,2
1Laboratorios de Investigación y Desarrollo, Centro de Investigación para el Desarrollo Integral y Sostenible (CIDIS), Facultad de Ciencias e Ingeniería, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Lima, Perúepartment, Institute/University, Address, Country; 2 Departamento de Geología, Universidad de Salamanca, Salamanca, 37008, España.
*Corresponding author: axeltej96@gmail.com
The expansion or contraction of tropical and subtropical deserts due to global warming remains uncertain, with major implications for food security and habitability. Paleobotanical records are crucial for understanding how dry-tolerant ecosystems evolved under past greenhouse conditions, but their study is hindered by limited sedimentary records and references. This research offers a detailed palynological characterization of over 175 dry-tolerant genera from xeric climates along the Western South American Pacific coast, aiming to provide a taxonomically reliable guide for future (paleo)palynological studies. Samples were collected from geolocated Herbarium material and processed, while botanical names were reviewed and updated. The resulting database includes 202 palynomorph types from 181 spermatophyte and 19 fern species, representing 175 genera from 70 families. Each genus is linked to at least one palynomorph type, with detailed descriptions of species names, symmetry, polarity, size, exine features, apertures, and other key traits. Duplicate slides are housed at multiple institutions to enhance accessibility. This georeferenced, voucher-linked reference is a foundational resource for morphological comparisons and for studying the evolution of dry-tolerant flora, plant-animal interactions, landscape changes, and human-plant relationships over time.
Scampi – The Digital Palynology Workflow
Wade, D.1*, Stefanowicz, S.1, Burgess, R.2, Anthonissen, E. 1, Cullum, A. 1
1 Equinor ASA, Forusbeen 50, 4035 Stavanger, Norway. 2 Equinor ASA, Sandsliveien 90, 5254 Sandsli, Norway
Corresponding authors: dawad@equinor.com, lsst@equinor.com, rdb@equinor.com, cullum@equinor.com
The Norwegian Offshore Directorate (NOD) is working on a large digitalization project to convert their vast archive of palynology slides into a digital format. This project aims to bring the field of biostratigraphy into the digital age. The archive consists of around 150,000 slides, with up to 20,000 fossils per slide, totalling around 3 billion fossils needing analysis. To make this process more feasible, a scalable and efficient methodology is needed to classify and study these fossils.
Recent studies have shown that latent-space clustering of microfossil images can be utilized to identify relevant groups of fossils (Wade et al. DigEx 2023 & FORCE Cross Border Seminar 2023). This approach has been further enhanced by incorporating a Content-Based Image Retrieval (CBIR) system that has been designed specifically to fulfil the requirements of palynologists. This system functions as a robust search engine that has been customized to meet the specific needs of professionals in this field.
This approach utilizes computer-vision techniques to automatically extract individual microfossil images from whole-slide images of scanned palynology slides. This facilitates a seamless comparison of any arbitrary 'query' image with millions of individual images obtained from any given well, swiftly returning the most relevant matches for expert appraisal. The process is repeated for multiple ‘queries’ of known taxonomy, which results in an accelerated classification workflow and builds up large numbers of expert-verified species identifications. These microfossil observations of dinoflagellate cysts, algae, pollen, and spores can be plotted by depth, allowing for the creation of the range charts. Furthermore, the approach enables uniform analyses of multiple wells, supporting comprehensive geological assessments at the field and regional scale.
One of the crucial aspects of the system is that efficiency is not prioritized over reliability. It has been designed with a strong focus on auditability and explainability, ensuring high levels of confidence in species counts. The powerful analytical capabilities of Scampi, powered by its advanced image processing algorithms, unlocks the potential for innovative workflows that were formerly infeasible. For example, Scampi can calculate accurate abundance ratios, which are crucial for meticulous biofacies characterization, an essential factor for precise interpretations of environmental and climatic conditions.
The implementation of this system has enormous practical implications for the field of palynology. Equinor has acknowledged the transformative potential of our approach and is integrating Scampi into the workflow as a minimum viable product. Moreover, the impacts of this tool go beyond palynology, as it has the potential to redefine the workflows in subsurface analysis and paleoenvironmental reconstruction. Scampi's outstanding efficiency in analysis heralds a new era of speed and precision in fossil identification and counting.
Palynology of the glacial sediments associated with the End Ordovician southern polar ice sheet
Wellman, C. H.1*
1School of Biosciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN, U.K.
*Corresponding author: c.wellman@sheffield.ac.uk
As the Late Ordovician ice age came to an end the enormous ice sheet, located over the Southern Pole on Gondwana, began to disintegrate and eventually disappeared. During this process huge quantities of sediments were deposited as diamictites and associated glacial sediments. Concomitantly sea level rose and the sea transgressed over previously glaciated areas, reworking glacial deposits and depositing shallow marine sediments. The glacial sediments are extremely complex and can be difficult to decipher because: (i) there was a large amount of sediment reworking as the sea transgressed over the deposits; (ii) they contain few fossils of biostratigraphical value other than palynomorphs; (iii) analysis of the palynomorphs is complicated by reworking that occurred during both glacial downcutting and the subsequent marine transgression that reworked the glacial deposits. In this talk I will attempt to correlate and interpret deglaciation sequences reported from around the Ordovician southern polar ice sheet (from North Africa, Saudi Arabia, South Africa, West Africa and South America) based on their lithostratigraphy and palynological content. This review suggests that the ice sheet was short lived, with both initiation and destruction rapid, and incorporated at least one episode of partial retreat/re-advance. The ice age is associated with the well documented Late Ordovician Mass Extinction (LOME). However, evidence of extinction among the primary producers (terrestrial plant spores and marine phytoplankton-acritarchs) is ambiguous.