TS4.2 | Data and models constraining Earth’s deep-time paleogeography
EDI
Data and models constraining Earth’s deep-time paleogeography
Convener: Sabin Zahirovic | Co-conveners: Alexandre Pohl, Anta-Clarisse Sarr, Maelis Arnould, Jonathon Leonard
Orals
| Fri, 28 Apr, 14:00–15:45 (CEST)
 
Room K1
Posters on site
| Attendance Fri, 28 Apr, 10:45–12:30 (CEST)
 
Hall X2
Posters virtual
| Attendance Fri, 28 Apr, 10:45–12:30 (CEST)
 
vHall TS/EMRP
Orals |
Fri, 14:00
Posters on site |
Fri, 10:45
Posters virtual
Fri, 10:45
The interplay of deep Earth processes with evolving atmospheric and hydrospheric conditions has shaped our planetary surface over billions of years. These solid Earth processes have modulated planetary habitability and biological evolution, driving biogeographic dispersal of species, as well as influencing oceanic and atmospheric circulation, climate, sea level, and even the emplacement of key economic mineral deposits. Recent decades have largely seen a focus on paleogeographic models incorporating plate tectonic reconstructions and mantle convection models. However, in recent years the improvement in computational resources and development of Earth system tools have cleared the way towards exciting deep-time Earth models with increasing complexity (such as biosphere feedbacks and carbon cycling) and spatio-temporal resolution. In addition, more attention has been given to sedimentological, paleobiological, and other geological and proxy data to constrain models of paleogeography, paleo-climate and surface processes.

We invite submissions from areas of tectonics, geodynamics, paleogeography, sedimentology, paleoclimatology, and all fields related to constraining Earth’s ancient geographies and the processes that shape them. We welcome submissions that are analytical or lab-focused, field-based, or involve numerical modelling of one or more Earth system components at regional or global scales. The session will also celebrate the contributions of early career researchers, open/community philosophy of research, and innovations that have adopted inter-disciplinary approaches.

Orals: Fri, 28 Apr | Room K1

Chairpersons: Sabin Zahirovic, Maelis Arnould, Alexandre Pohl
14:00–14:05
5-minute convener introduction
14:05–14:15
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EGU23-3337
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ECS
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solicited
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Virtual presentation
Paleogeography: a driver for past climate changes? 
Chloé Marcilly and Trond H. Torsvik

CO2 is the most important greenhouse gas in the Earth’s atmosphere and has fluctuated considerably over geological time. However, proxies for past CO2 concentrations have large uncertainties and are mostly limited to Devonian and younger times. Consequently, CO2 modelling plays a key role in reconstructing past climate fluctuations.

Silicate weathering and subsequent carbonate deposition are widely recognized to compose the primary sink of carbon on geological timescales and are largely influenced by changes in climate, which in turn are linked to changes in paleogeography. The role of paleogeography on silicate weathering fluxes has been the focus of several studies in recent years and mostly aiming to constrain climatic parameters such as temperature and precipitation affecting weathering rates through time. However, constraining the availability of exposed land is crucial in assessing the theoretical amount of weathering on geological time scales. Associated with changes in climatic zones, the fluctuation of sea-level is critical for defining the amount of land exposed to weathering. The current reconstructions used inmodels tend to overestimate the amount of exposed land to weathering at periods with high sea levels. Through the construction of continental flooding maps, we have constrained the effective land area undergoing silicate weathering for the past 540 million years. Our maps not only reflect sea-level fluctuations but also contain climate-sensitive indicators such as coal (since the Early Devonian) and evaporites to evaluate climate gradients and potential weatherablity through time. This is particularly important after the Pangea supercontinent formed but also for some time after its break-up.

We here investigate the potential link between land availability dictated by paleogeography and climate changes during the Phanerozoic. Recent studies have shown that continental glaciations occur following periods of decreasing atmospheric CO2, and these periods correspond to peaks in land availability at tropical latitudes. This link tends to attribute such changes to the paleogeographic evolution of our planet but this is not the case for the enigmatic end-Ordovician cooling where the increase in land availability prior to the Hirnantian glaciation appears not to have been enough to counteract the increase in solar energy and initiate cooling.

How to cite: Marcilly, C. and Torsvik, T. H.: Paleogeography: a driver for past climate changes?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3337, https://doi.org/10.5194/egusphere-egu23-3337, 2023.

14:15–14:25
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EGU23-2503
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ECS
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On-site presentation
The spatiotemporal distributions of global paleo-Köppen climate belts during the Mesozoic-Cenozoic 
Chenmin Yu, Shuo Cao, Laiming Zhang, and Chengshan Wang

Climate paleogeography refers to adding climatic information to traditional paleogeographic maps by using paleoclimate classifications. Here we present a series of global paleo-Köppen climate maps from 250 Ma to 0 Ma (per 10 million years) with a high resolution based on the quantitative paleoclimate data simulated by Li et al. (2022). Based on these maps, we evaluate the areal and latitudinal evolutions of paleo-Köppen climate belts during the Mesozoic-Cenozoic. Based on an updated classification that divides “Hothouse”, “Greenhouse”, and “Icehouse” states by global average temperature, we evaluate the areal, latitudinal, and altitudinal characteristics of the paleo-Köppen climate belts for different climate states.

How to cite: Yu, C., Cao, S., Zhang, L., and Wang, C.: The spatiotemporal distributions of global paleo-Köppen climate belts during the Mesozoic-Cenozoic, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2503, https://doi.org/10.5194/egusphere-egu23-2503, 2023.

14:25–14:35
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EGU23-11556
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ECS
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On-site presentation
Subduction, continental collision, and mantle dynamics in the Mediterranean - Tethyan realm: impact on oceanic circulation, climate, and the biosphere 
Eivind Straume, Bernhard Steinberger, Thorsten Becker, and Claudio Faccenna

Topography generated by subduction, mantle flow, volcanism, and continental collision in the Eastern Mediterranean – Tethyan realm enabled migration and diversification of terrestrial and marine faunas and facilitated Cenozoic (66 – 0 Ma) oceanographic and climatic changes. However, the topographic evolution of key regions and events such as closing the link between the Atlantic and Indo-Pacific Oceans through the Tethys Seaway, and the potential link between the Arctic Ocean and Paratethys Sea through the West Siberian Seaway, are still debated. Here, we review a series of published regional paleogeographic indicators including geological and biogeographic data and generate a new, continuous Cenozoic (i.e.,1 Myr time intervals) digital elevation model for the Tethyan realm. Recent paleoclimate modeling using a state-of-the-art Earth system model (the NorESM-F) show that related, and relatively small changes in paleogeography in these regions can cause large global ocean circulation changes. In particular, shallowing the Tethys Seaway facilitates a stronger overturning circulation in the Atlantic Ocean, while an open West Siberian Seaway may cause freshwater leakage from the Arctic Ocean; this weakens the overturning in the Atlantic Ocean if the Tethys Seaway is open. We further investigate the possible contribution of mantle convection to the evolution of this regional system using new, time-evolving dynamic topography models, and examine the consequences for mammal migration, ocean circulation, and climate. We show that paleotopographic changes in the West Siberian Seaway correlate with changes in dynamic topography. Our findings indicate a link between deep mantle convection, surface evolution, and climatic changes on geological timescales.

How to cite: Straume, E., Steinberger, B., Becker, T., and Faccenna, C.: Subduction, continental collision, and mantle dynamics in the Mediterranean - Tethyan realm: impact on oceanic circulation, climate, and the biosphere, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11556, https://doi.org/10.5194/egusphere-egu23-11556, 2023.

14:35–14:45
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EGU23-12697
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ECS
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On-site presentation
Rift escarpment retreat sustains dynamic landscape for Malagasy flora speciation 
Yanyan Wang, Sean Willett, Yi Liu, Niklaus Zimmermann, and Loïc Pellissier

A high-relief escarpment characterizes the modern topography of the rifted margin of eastern Madagascar. Although it remained tectonically inactive since the formation from rifting with Seychelles-India in the late Cretaceous, the escarpment landscape has been evolving actively, in that the escarpment retreats laterally due to differential erosion between the escarpment and the high plateau since rifting. The topographically active escarpment of Madagascar corresponds to the island's high endemic species richness, although the island itself is a well-known biodiversity hotspot globally.

To investigate the role of tectonic-geomorphic processes in shaping the plant diversity of Madagascar, we constructed a model of elevation change over the entire island. Four geological processes were analyzed for the elevation change: the dynamic uplift from mantle upwelling, the escarpment retreat, the faulting in the Ankay-Alotra Graben, and the sporadic volcanism on the island. We then related the model elevation changes to the phylogenetic patterns and mapped species richness of seed plants. Correlation analysis showed consistence between the observed species richness pattern and the elevation change, in particular, elevation change from the escarpment retreat showed the best correlation with the high species richness.

We hypothesized that escarpment retreat leads to vicariant speciation and accumulates the species lineages along the escarpment region over geological time. To demonstrate how the surface processes on an escarpment are linked to speciation, we constructed a landscape evolution model simulating fluvial erosion of an escarpment on the edge of a pre-existing, topographic highland. The model shows that the escarpment retreats laterally, and the drainage basins become longer and broader. However, the basin growth rates are heterogeneous, and the main divide develops sinuosity as individual drainage basins grow at different rates. The differential and transient erosion rates between catchments lead to increased segregation of elevation bands between watersheds, creating isolated highlands detached from the escarpment slope, and providing a highly fragmented habitat in both space and time. The habitat connectivity constantly evolves during the retreat, which we believe, links closely to speciation through the various observed morphological processes.  

Retreat of the Madagascar escarpment indirectly influences the orographic precipitation and climatic conditions in that the tropical climatic conditions are sustained, and the tropical habitat expands area during the retreat, both are known favorable conditions of speciation. Overall, we conclude that the escarpment retreat sustains a dynamically evolving landscape, which consequently fosters the flora species hotspot of Madagascar, likely through vicariant speciation.

How to cite: Wang, Y., Willett, S., Liu, Y., Zimmermann, N., and Pellissier, L.: Rift escarpment retreat sustains dynamic landscape for Malagasy flora speciation, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12697, https://doi.org/10.5194/egusphere-egu23-12697, 2023.

14:45–14:55
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EGU23-4248
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On-site presentation
Finding Argoland: reconstructing a lost continent in SE Asia 
Eldert Advokaat and Douwe van Hinsbergen

Can continents get lost? The geological textbooks predict that when continents enter subduction zones, subduction either stops, or part of the crust is scraped off and preserved in orogens. A possible exception has been the conceptual continent of Argoland. Argoland must have been broken off the NW Australian margin in the Late Jurassic and migrated north to end up somewhere in SE Asia, but the previously identified fragments that may form candidates are too small to represent all of Argoland, and the geology shows that they were once separated by oceanic basins that are much older than the Late Jurassic. 

We compiled the orogenic architecture and the geologic record of SE Asia and the NW Australian margin. We identified Gondwana-derived units that collectively may represent Argoland. These fragments are found between relics of Late Triassic to Middle Jurassic oceanic basins that all pre-date the break-up of Argoland. We systematically restore deformation within SE Asia in the upper plate system above the Sunda trench, use this to estimate where Gondwana-derived fragments accreted at the Sundaland (Eurasian) margin in the Cretaceous, and subsequently reconstruct their tectonic transport back to the Australian-Greater Indian margin. Our reconstruction shows that Argoland originated at the northwest Australian margin between the Bird’s Head in the east and Wallaby-Zenith Fracture Zone in the west, south of which it bordered Greater India. We show that the lithospheric fragment that broke off northwest Australia in the Late Jurassic was a collage of continental fragments and intervening oceanic basins.

How to cite: Advokaat, E. and van Hinsbergen, D.: Finding Argoland: reconstructing a lost continent in SE Asia, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4248, https://doi.org/10.5194/egusphere-egu23-4248, 2023.

14:55–15:05
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EGU23-14003
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On-site presentation
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New tools on Terra Antiqua 2.0 applied to reconstructing the paleogeography of the India-Asia collision 
Guillaume Dupont-Nivet, Jovid Aminov, Diego Ruiz, Thomas van der Linden, Boris Gailleton, Pierrick Roperch, Fernando Poblete, Niels Meijer, Mustafa Kaya, Alexis Licht, Aude Gébelin, Xiaomin Fang, Xiaoping Yuan, and Douwe van Hinsbergen

Terra Antiqua is a plugin for QGIS to make paleogeographic reconstructions with a user-friendly graphical interface. The goal of Terra Antiqua is to make paleogeographic reconstructions accessible and attractive to a much wider range of users, typically Earth and Life scientists and students, without extensive expertise in programming and GIS analyses. Yet Terra Antiqua can also be attractive for GIS developers as our reconstruction algorithms are accessible through application programming interfaces (APIs), open source Github repository and written in python with open standards (e.g. OpenLayers, OGC, GDAL). Starting from physiographic features and datasets rotated back to the desired reconstructed age (typically using Gplates), the previous release of Terra Antiqua offered a set of primary tools to run the main steps of a global reconstruction (1. Combine topo-/bathymetry, 2. Set Paleoshorelines, 3. Modify topo/bathymetry and 4. Create topo/bathymetry) and secondary tools to improve and enhance the result. From this first simple release we are incrementally adding tools and features inspired by various methods developed by experienced paleogeographers. The new release, Terra Antiqua 2.0, has integrated a new set of options on the existing tools, including the ability to create physically realistic geomorphic features. These new options will be presented within the controversial example of the reconstruction of the India-Collision and the development of the Tibetan-Himalayan orogen. Several reconstructions stemming from competing topographic and geodynamic models are thus compared and assessed based on compiled datasets including updated paleoaltimetry.

How to cite: Dupont-Nivet, G., Aminov, J., Ruiz, D., van der Linden, T., Gailleton, B., Roperch, P., Poblete, F., Meijer, N., Kaya, M., Licht, A., Gébelin, A., Fang, X., Yuan, X., and van Hinsbergen, D.: New tools on Terra Antiqua 2.0 applied to reconstructing the paleogeography of the India-Asia collision, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14003, https://doi.org/10.5194/egusphere-egu23-14003, 2023.

15:05–15:15
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EGU23-12062
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ECS
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On-site presentation
Structural uncertainty in full-plate reconstructions as a way to account for lost intra-oceanic plate boundaries 
Andrew Merdith and Maëlis Arnould

The past decade has seen the rise of fully kinematic palaeogeographic models that explicitly define the evolution of both plate boundaries and tectonic plates. Included in these models are (possible) interpretations of spreading systems in extinct ocean basins. Typically, the primary constraint on controlling these synthetic mid-ocean ridges is ensuring that at known (i.e. preserved in the geological record) subduction zones there is convergence, and that at modelled mid-ocean ridges there is divergence. The most common way this is expressed in models is through a quasi-stable triple junction. While obviously subject to large inherent uncertainties, the advantage of modelling such ocean basins is that they can provide an internally consistent model of (tectonic) ocean evolution, tied to the underlaying palaeomagnetic and palaeotectonic framework. Here we explore this inherent uncertainty in such synthetic ocean basins, by introducing the concept of ‘structural uncertainty’ within a full-plate model. We describe structural uncertainty as the answer to the question, “how much oceanic-oceanic subduction (i.e. not preserved in the geological record) is required to balance the modelled synthetic spreading ridges?” While an initial inclination that models tending to ‘zero’ might be best, we entertain the possibility that there is a range of ‘lost’ subduction. To assess this hypothesis, we also interrogate whole-mantle convection models that produce self-consistent plate tectonics to determine the proportion of subduction around or adjacent to continents (representative of what might be preserved in the geological record), and subduction occurring within ocean basins (representative of what might be lost to the geological record).

How to cite: Merdith, A. and Arnould, M.: Structural uncertainty in full-plate reconstructions as a way to account for lost intra-oceanic plate boundaries, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-12062, https://doi.org/10.5194/egusphere-egu23-12062, 2023.

15:15–15:25
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EGU23-9519
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Virtual presentation
LithoPlates - a new deep-time reconstruction community service provided by the AusGeochem data platform 
Fabian Kohlmann, Wayne P. Noble, Xiaodong Qin, Jamie Higton, Romain Beucher, Moritz Theile, and R. Dietmar Müller

AusGeochem, together with the Earthbyte Group and Lithodat, has developed a cloud-based, fully integrated deep time reconstruction tool for geochemistry data based on Earthbyte’s pyGplates and plate models. This new tool is easy to use and enables researchers to visualise and analyse samples and analytical results in their palinspastic context. On-the-fly analytical tools currently included in AusGeochem such as live contouring and multi-sample selections can now be performed in their paleogeographic locations without any further data preparation. The ease of use will enable researchers to explore the world of deep-time reconstructions and enhance their understanding of the tectonic settings and events of importance to rock, mineral or fluid sample history. The current version enables the user to select between 7 different plate models ranging back to 1 Ga. All images and results can be exported for further analysis and processing.

 

Here we present how this new tool can be used and how it is integrated into AusGeochem, Australia's public geochemistry data platform for FAIR data. Geochronology data can be reconstructed back in time to help understand when and where rocks were formed or deformed, and how they are related in a paleogeographic context. Filters can be applied to make sure only data of age relevance are shown in any given reconstruction timeslice. The advantage of having the new reconstruction function fully integrated into AusGeochem’s relational database is that all data and metadata can be analysed using the same on-the-fly tools in both present-day and palinspastic geography. . This new tool is primarily designed for researchers interested in the paleogeographic context of their samples, but also for plate model scientists seeking to integrate all available geochronology and thermochronology data to help better constrain and improve existing plate models. Future enhancements will include the addition of more deep-time plate models, advanced visualisation and filters and a comparison of multiple model outputs. 

How to cite: Kohlmann, F., Noble, W. P., Qin, X., Higton, J., Beucher, R., Theile, M., and Müller, R. D.: LithoPlates - a new deep-time reconstruction community service provided by the AusGeochem data platform, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9519, https://doi.org/10.5194/egusphere-egu23-9519, 2023.

15:25–15:35
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EGU23-4125
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ECS
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On-site presentation
Integration of deep-time databases: towards building a deep-time digital Earth 
Haipeng Li, James Ogg, Daven Quinn, Christopher Scotese, Honghe Xu, Shanan Peters, Jun Wang, Linna Zhang, Mingcai Hou, Linshu Hu, Sabrina Chang, and Luoqi Wang

The integration of deep-time databases is a key aspect in the creation of a comprehensive digital model of Earth's history, known as the "deep-time digital Earth." This model would enable scientists to better comprehend the intricate processes that have shaped our planet and its life forms over time. Currently, the data are dispersed across various databases and research institutions, making it challenging for scientists to fully utilize the information contained in the data.

We present a virtual integration of deep-time databases, where the data remain in the sources and are accessed as needed at query time. We will demonstrate this integration using the Macrostrat, PBDB, GBDB, GeoLexicon, and the Paleogeographic Atlas Project databases. The first step involves identifying the available information from each data source and deciding on the relevant data attributes, such as lithology, age, and formation name. The next step is aligning the schemata of different data sources to a common mediated schema, allowing attribute names with the same semantics to be merged. For example, Palaeo-block in GBDB is equivalent to geoplate in PBDB. The third step is to create a virtual integration layer that allows users to access and query data from various sources as if they were stored in a single database. This virtual integration layer uses the mediated schema to translate queries and data among different sources and provides tools and interfaces for data visualization and analysis. Our goal is to make deep-time data more easily accessible and usable for a better understanding of Earth's history.

How to cite: Li, H., Ogg, J., Quinn, D., Scotese, C., Xu, H., Peters, S., Wang, J., Zhang, L., Hou, M., Hu, L., Chang, S., and Wang, L.: Integration of deep-time databases: towards building a deep-time digital Earth, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4125, https://doi.org/10.5194/egusphere-egu23-4125, 2023.

15:35–15:45
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EGU23-3663
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On-site presentation
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Databases for China-Indochina Paleogeography 
James Ogg, Linna Zhang, Hongfei Hou, Bui Dong, Mingcai Hou, Junxuan Fan, Wen Du, Sabrina Zhang, and Haipeng Li

            Building paleogeographic maps requires team efforts to compile databases of regional sedimentary and volcanic facies, to validate and update information, and to develop visualization and computer projection methods. We have worked with experts on regional geologic systems to assemble cloud-based detailed lexicons of all geologic formations within China-Indochina regions (ca. 3000 formations as of March 2023; http://chinalex.geolex.org; vietlex.geolex.org; thailex.geolex.org). A parallel program through the past decade by the Geobiodiversity Database (GBDB) team has completed a detailed grid of outcrops and borehole stratigraphic-biostratigraphic columns for much of China (http://www.geobiodiversity.com). The GBDB had initially focused on the Early Paleozoic; for example, the Ordovician portion for the South China plate contains detailed stratigraphic information at biozone level from 750 exposed sections. The user interfaces for both projects include various search options, and map or stratigraphic navigation. Both of these database projects are now components of the paleogeography program of the IUGS Deep-time Digital Earth system (deep-time.org).

            These databases enable display of all lithologies of a desired time horizon onto the modern geography or onto modeled plate reconstructions of that geologic age. For the interlinked Lexicon databases of China-Indochina (and the Indian Plate), the auto-merged output provides a visualization of all formations as polygons filled with a colored generalized facies pattern projected onto the dispersed Asian plates (Du et al., Geoscience Data Journal, 2023). The GBDB database produces very detailed isopach and paleogeographic depositional-facies reconstructions, for example the paleogeography and sediment patterns of South China for each Ordovician stage (Zhang, L.N., et al., Earth-Science Reviews, 2023).

            The main coordinators for the China Lexicon database include Gao Linzhi (Precambrian), Shanchi Peng (Cambrian), Xiaofeng Wang (Ordovician-Silurian), Hongfei Hou (Devonian), Xiangdong Wang (Carboniferous), Rennong Wang (Permian), Jinnan Tong (Triassic), Jingeng Sha (Jurassic), Wan Xiaoqiao (Cretaceous) and Deng Tao (Cenozoic); and the details will be published in a forthcoming Stratigraphic Lexicon of China. For Vietnam, the team at Vietnam National University provided extensive updates and GeoJSONs to their previous published-book compilation by Tran Van Tri and Vu Khuc (Editors, 2011; Geology and Earth Resources of Viet Nam, General Dept. of Geology and Minerals of Viet Nam).

How to cite: Ogg, J., Zhang, L., Hou, H., Dong, B., Hou, M., Fan, J., Du, W., Zhang, S., and Li, H.: Databases for China-Indochina Paleogeography, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3663, https://doi.org/10.5194/egusphere-egu23-3663, 2023.

Posters on site: Fri, 28 Apr, 10:45–12:30 | Hall X2

Chairpersons: Maelis Arnould, Alexandre Pohl, Jonathon Leonard
X2.158
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EGU23-994
On the reliability of the Panalesis (v.0) paleogeographic maps 
Christian Vérard

Palæogeography is the definition of the geography of the Earth in the geological past. However, geography depends on topography (both on land and under the sea) and the sea level which defines the coastline. Topography is a multifactorial resultant whose heart is the geodynamic context that created it (Vérard, 2019). In other words, there are no palæogeographic reconstructions if there is no plate tectonic model underlying them.

The palæogeographic maps presented here are derived from the Panalesis model (preliminary version or v.0), corresponding to palæo-digital elevation models (palæo-DEM) that cover the entire Phanerozoic on a global scale associated with sea level variations from Haq et al. (1987, 2008, 2018).

The results show two main facts. First, the main shortcomings of the method for converting a plate tectonic map to a palæogeographic map (Vérard et al., 2015) are relatively well understood and should be improved with new versions of the plate tectonic model (Verard, 2021) and the conversion code. Secondly, lithofacies databases (fossils and palæo-environments) on a global scale are needed to identify areas that are outside the “standard mode” defined by synthetic topographies and to understand the reasons for the discrepancies. Conversely, variations (global to regional) in lithofacies can only be understood if a quantified topographic model is proposed as a reference, which Panalesis is, to date, the only one to systematically offer.

 

REFERENCES

1. Vérard, C., 2019. Panalesis: Towards global synthetic palaeogeographies using integration and coupling of manifold models. Geological Magazine, 156 (2), 320-330.

2.1. Haq, B. U., Hardenbol, J., Vail, P. R., 1987. Chronology of fluctuating sea levels since the Triassic. Science, 235 (4793), 1156-1167.

2.2. Haq, B. U., Schutter, S. R., 2008. A chronology of Paleozoic sea-level changes. Science, 322 (5898), 64-68.

2.3. Haq, B. U., 2018. Triassic eustatic variations reexamined. The Geological Society of America (GSA Today), 28, 6 pages.

3. Vérard, C., Hochard, C., Baumgartner, P. O., Stampfli, G. M., 2015. 3D palaeogeographic reconstructions of the Phanerozoic versus sea-level and Sr-ratio variations. Journal of Palaeogeography, 4 (2), 167-188.

4. Vérard, C., 2021. 888 – 444 Ma global plate tectonic reconstruction with emphasis on the formation of Gondwana. Frontiers in Earth Science, 9 (666153), 28 pages.

How to cite: Vérard, C.: On the reliability of the Panalesis (v.0) paleogeographic maps, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-994, https://doi.org/10.5194/egusphere-egu23-994, 2023.

X2.159
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EGU23-1136
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ECS
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Kinematic reconstruction of the Tibetan-Himalayan orogen since the Cretaceous 
Thomas Schouten, Lydian Boschman, Shihu Li, and Sean Willett

Knowledge of the kinematic evolution of the Tibetan-Himalayan orogenic system is paramount to understand the geodynamics, development of topography and climate changes in a region that contains some of the world’s most important biodiversity hotspots. The tectonic framework however has been controversial with multiple models proposed. The Late Cretaceous to Palaeogene anomalously high velocity of the Indian plate has been hypothesised to be caused by two north-dipping subduction zones, and the arrival of the continental margin of the Indian plate is considered to have triggered both the slowdown of the Indian plate as well as a phase of overriding plate deformation. Here, we present a quantitative reconstruction of the tectonic evolution of this orogen with particular focus on deformation of the upper plate, which is responsible for the topographic evolution. We build our reconstruction in GPlates using a systematic reconstruction protocol. To this end, we review the geology and orogenic architecture of the Tibetan-Himalayan orogen. We present a single reconstruction for the evolution of the overriding Eurasian plate. We show that this reconstruction is consistent with palaeomagnetic and seismic tomographic data. We then reconstruct three alternative tectonic and palaeogeographic scenarios for the lower plate based on data from the Himalaya, Burma and Kohistan, whose sparsity permits multiple interpretations. Whereas one of our scenarios is consistent with the hypothesis that Late Cretaceous acceleration of the Indian plate was driven by two subduction zones, we demonstrate that it does not explain early Eocene acceleration. Moreover, the notion that the arrival of the Indian continental margin triggers a phase of overriding plate deformation is supported by only by one of our scenarios, in which this occurs at 25 Ma. None of our scenarios however support the hypothesis that the arrival of the Indian continental margin corresponds to the middle Eocene slowdown of the Indian plate. Finally, our reconstructions provide the platform for future work to include reconstructions of palaeotopography and palaeoclimate to identify the environmental changes that may have driven the development of regional biodiversity hotspots.

How to cite: Schouten, T., Boschman, L., Li, S., and Willett, S.: Kinematic reconstruction of the Tibetan-Himalayan orogen since the Cretaceous, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-1136, https://doi.org/10.5194/egusphere-egu23-1136, 2023.

X2.160
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EGU23-2171
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ECS
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Indian Plate stratigraphic units: On-line open-access database (Lexicon), including options to display sediment and volcanic facies onto plate reconstructions 
ONeil Mamallapalli, Raju DSN Datla, Nallapa Reddy Addula, Nusrat Kamal Siddiqui, James Ogg, Gabriele Ogg, Sabrina Chang, Wen Du, Suyash Mishra, Aaron Ault, Bhargava N Om, and Birendra P Singh

Our international team has worked with regional experts to compile details on nearly every geologic formation of the Indian Plate from Proterozoic through Quaternary. This suite of nearly 1000 sedimentary and volcanic formations includes India, Pakistan, Nepal, Bhutan, Sri Lanka, Bangladesh and Myanmar, plus all offshore sedimentary basins that have been explored for hydrocarbons. The data for each formation includes its lithologic succession, fossil content, age­ span details, regional extent and images of stratigraphic columns/outcrops/etc. (when available). The geologic age spans (as percent-up in stages) are auto-converted to numerical ages using a look-up table (currently Geologic Time Scale 2020), and the regional extents include GeoJSON coding. APIs provide open access to this information for other applications.

The user can explore this information using a map interface, stratigraphic-column interfaces (generated with TimeScale Creator software), and a variety of search filters (including and/or logic for words within lithologic descriptions). An additional option on the displayed output is to display either a single formation GeoJSON or an age-suite of formation GeoJSONs as facies­ pattern-filled polygons onto a user-selected plate reconstruction model for that appropriate age via a one-click activation of pyGPlates-pyGMT graphics.

This cloud-based database and website (currently at indplex.geolex.org/index.php) will be hosted and maintained by the Geologic Society of India in coordination with colleagues in Pakistan and other nations. Our online Indian Plate database currently links to adjacent regional lexicons of China and Indochina for regional paleogeographic displays, and is intended to share age-facies­ location information with stratigraphic databases of Australia, MacroStrat, One-Stratigraphy, etc., within the lUGS Deep-Time Digital Earth system, to generate paleogeographic visualizations of any desired geologic age onto any plate-motion model.

How to cite: Mamallapalli, O., Datla, R. D., Addula, N. R., Siddiqui, N. K., Ogg, J., Ogg, G., Chang, S., Du, W., Mishra, S., Ault, A., Om, B. N., and Singh, B. P.: Indian Plate stratigraphic units: On-line open-access database (Lexicon), including options to display sediment and volcanic facies onto plate reconstructions, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2171, https://doi.org/10.5194/egusphere-egu23-2171, 2023.

X2.161
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EGU23-2243
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ECS
A new Permian-Triassic paleogeographic reconstruction for the East Asian blocks 
Qiang Ren, Anqing Chen, and Mingcai Hou

The East Asian blocks were important parts involved in Pangea formation, and their paleogeographic evolution during the late Paleozoic was controlled by two tectonic domains: the Paleo-Asian Ocean (PAO) and the East Paleo-Tethys Ocean (EPTO). Although some tectonic reconstructions of East Asia have been proposed, there has been a great contradiction between them and paleobiogeographic models during Permian. We have recently complied the Permian-Triassic East Asian paleomagnetic database and reconstructed the paleogeography of East Asia in combination with paleontological (e.g., data from the Paleobiology Database) and geological evidence. The new reconstruction for the East Asian blocks exhibited that the Xilinhot-Songliao Block was located between the eastern PAO and the EPTO during the early Permian and was the intermediate unit that separated the two tectonic domains. The Paleo-Tethys Ocean was a wider east-west range than most previous version. It strongly supports Torsvik et al. (2008)’s view that the absolute paleogeographic position of the South China Block reconstructed by the eruption of the Emeishan large igneous province (~260 Ma) at the margin of the Large Low Shear wave Velocity Provinces. During 265-255 Ma, the East Asian blocks moved rapidly northward, which probably accelerated the end‐Guadalupian mass extinction in East Asia. The PAO closed completely at 250 Ma, and thus the tectonic framework of the Northeast Asian continent was basically formed. Since then, East Asia began to transform into a new evolutionary stage of the superposition of multiple tectonic regimes: (1) the north Mongol–Okhotsk Ocean (between Siberia and Amuria) had sustained scissor-like closure from west to east during the Mesozoic period; (2) the east Paleo-Pacific oceanic plate had undergone westward successive subduction and accretionary since the early Mesozoic (e.g., formed the Nadanhada accretionary terrane and the Sikhote orogenic belt); (3) the southwest Tethyan blocks (e.g., North/South Qiantang, Lhasa, Indochina, Sibumasu) experienced a rapid northward movement accompanied by intense subduction and collision.

How to cite: Ren, Q., Chen, A., and Hou, M.: A new Permian-Triassic paleogeographic reconstruction for the East Asian blocks, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2243, https://doi.org/10.5194/egusphere-egu23-2243, 2023.

X2.162
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EGU23-3648
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Online Databases of Geologic Formations of Asia and Africa, with Display onto Plate Reconstructions for Any Time Horizon 
Gabriele Ogg, Sabrina Chang, Wen Du, James Ogg, Suyash Mishra, Sabin Zahirovic, Aaron Ault, O'Neil Mamallapalli, Haipeng Li, and Hongfei Hou

Two goals of the Paleogeography Working Group of the Deep-Time Digital Earth (DDE) program of the International Union of Geological Sciences (IUGS) are: (1) to interconnect national databases for all geologic formations, and to compile new online "lexicons" for countries that currently lack these; (2) to display the merged paleogeographic output for any time interval of these distributed databases onto appropriate plate tectonic reconstructions.

Therefore, we have worked with regional and time-period experts to compile cloud-based lexicon databases for Asian and for select African regions. The new databases are currently completed for the Precambrian through Phanerozoic of Asia (ca. 4000 geologic formations as of March 2023) and of a part of Africa (Niger, ca. 200 formations). In addition to standard search criteria (age, region, lithology keywords, etc.), the user interfaces include map-based and stratigraphic-column navigation. The returned entries be displayed by-age or in alphabetical order. Many of the formation details include GeoJSON-formatted polygons of its regional extent. These enable plotting of the individual formations filled with their appropriate lithologic facies patterns onto any of three proposed plate reconstruction models with a single click. Or, if a geologic age is specified, a user can query all the linked regional databases to plot the locations of all formations (with lithologic facies patterns) that span that age onto a plate reconstruction model.

Our team is currently working with the teams at Macrostrat (Univ. Wisconsin (Madison) and at One-Stratigraphy (DDE, IUGS) and with other geologic surveys to interlink their regional facies-time compilations for other global regions. The goal is to users to access the information on any geologic formation, and to obtain a view of the sediments and volcanics that were accumulating at any time on the ancient Earth.

How to cite: Ogg, G., Chang, S., Du, W., Ogg, J., Mishra, S., Zahirovic, S., Ault, A., Mamallapalli, O., Li, H., and Hou, H.: Online Databases of Geologic Formations of Asia and Africa, with Display onto Plate Reconstructions for Any Time Horizon, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3648, https://doi.org/10.5194/egusphere-egu23-3648, 2023.

X2.163
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EGU23-10133
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ECS
Paleobathymetry reconstructions during the Mesozoic and uncertainties in oceanic gateway evolution 
Nicky Wright, Maria Seton, Aleece Nanfito, Nick Atwood, and Dietmar Müller

The reconstruction of paleobathymetry, in particular the evolution of oceanic gateways, has important implications for paleo-ocean circulation, paleoclimate, as well as biotic and faunal exchanges. During the past ~250 million years there have been major changes in paleobathymetry and oceanic gateways associated with the breakup of the Pangaea supercontinent, including the development of the North and South Atlantic ocean basins and the Central Atlantic seaway. Considerable research effort has been invested into better understanding the global evolution of paleobathymetry and oceanic gateways during the Cenozoic, but there remain large uncertainties about the timing of opening, closure, and physiographic evolution of Mesozoic oceanic gateways and seaways.

Here, we present new paleobathymetry reconstructions based on a recent global plate tectonic model (Müller et al., 2019) spanning the Triassic (~250 Ma) to the present. We reconstruct presently-preserved oceanic crust using new functionality developed in pybacktrack v1.4, a python module for backstripping and reconstructing paleobathymetry. For present-day submerged continental crust we use pybacktrack to reconstruct paleobathymetry based on its rifting and deformation history and assuming a single lithology for the progressive decompaction of sediments. In regions where ancient seafloor is now subducted, we use an established approach of synthetically reconstructing paleobathymetry based on the age-area distribution of oceanic crust (‘age grids’) convolved with an age-depth relationship to reconstruct basement depths followed by modelling effects from sediment thickness and seafloor volcanism including large igneous provinces. Our methodology additionally allows for alternative plate tectonic models (and/or absolute reference frames) to be integrated into reconstructions of paleobathymetry. Further, we use our new paleobathymetry reconstructions to explore the formation and evolution of pre-Cenozoic oceanic gateways. We find significant differences in the development and physiography of Mesozoic oceanic gateways and seaways in our new reconstructions compared to a widely used paleogeographic model, which has major implications for paleoceanographic models and interpretations of paleoclimate proxies.

How to cite: Wright, N., Seton, M., Nanfito, A., Atwood, N., and Müller, D.: Paleobathymetry reconstructions during the Mesozoic and uncertainties in oceanic gateway evolution, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10133, https://doi.org/10.5194/egusphere-egu23-10133, 2023.

X2.164
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EGU23-11026
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ECS
Linking detrital zircon and supercontinent over the past 3 billion years 
Dongchuan Jian, Simon Williams, Guochun Zhao, Shan Yu, and Bingxi Liu

The assembly, tenure, and breakup of supercontinents is thought to have played a prominent role in Earth’s plate tectonic history and deeply influenced the paleogeography, crustal deformation, magmatic activity, climate, and biology. To date, at least three supercontinents that once existed on Earth are supported by most geologists. The evolution of Pangea is relatively well-understood, and only a small number of plates are controversial. By contrast, investigations of Rodinia and Nuna have led to many disagreements due to the limited, ambiguous evidence preserved from the Precambrian. Resolving these issues requires the integration of a wide variety of geological data within a quantitative reconstruction framework. In our previous work we linked the reconstruction of Pangea to an extensive global database of detrital zircon samples, demonstrating that samples with different zircon age spectra characteristics help to identify the tectonic setting in which they were deposited – and more broadly, form coherent patterns that delineate the periphery and core of Pangea.

Here, we expand on our previous work to investigate the spatial and temporal characteristics of detrital samples deposited over the past 3 Ga. Although the number of available samples becomes more sparse back in time, the distribution patterns of the categorized samples in recent Rodinia reconstructions are nonetheless consistent with previous results for Pangea. General temporal trends reveal that, as supercontinents assemble, the proportion of samples characteristic of subduction tectonic settings increases while the proportion of samples from settings distal from subduction zones decreases, while the opposite trend defines periods of supercontinent dispersal. Together, these results show that quantitative reconstruction of global zircon databases holds important information related to past paleogeographic change.

How to cite: Jian, D., Williams, S., Zhao, G., Yu, S., and Liu, B.: Linking detrital zircon and supercontinent over the past 3 billion years, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-11026, https://doi.org/10.5194/egusphere-egu23-11026, 2023.

X2.165
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EGU23-14780
Paleogeographic and tectonic models of the Western Mediterranean 
Sheona Masterton, Peter Webb, Catherine Hill, Amanda Galsworthy, Lauren Raynham, Laura Wilson, and Harry Leah

Recent advances in plate modelling and deep-earth visualisation software present excellent opportunities to integrate spatial and temporal data from several earth science disciplines. These tools can enhance our understanding of tectonic and palaeogeographic evolution, with clear applications to resource exploration.

We present a case-study of our geodynamic visualisation package, in which we integrate ‘traditional’ rigid tectonic elements alongside dynamically evolving plate boundaries, tectonic and thermal events and paleogeographic mapping. We focus on the Western Mediterranean, where our developed tectonic model is derived from potential field data, structural analysis, and crustal architecture interpretations. Our model forms the basis for interpretations of palaeogeography at key reconstruction ages throughout the Cenozoic evolution of the area.

Our crustal architecture interpretations illustrate the nature of the crust and its deformation since Variscan. Key components of the model include: Variscan age fold and thrust belts in Iberia, a Cenozoic oceanic domain (Algerian-Ligurian-Provencal Sea) bounded by a magma-poor continent-ocean transition domain, a relatively undeformed continental block (Corsica-Sardinia) and a large expanse of attenuated crust associated with the rapid roll-back of the Calabrian Arc. Our model is constrained by both structural interpretation of gravity and magnetic data and their derivatives and 2D gravity and magnetic modelling of crustal profiles to match the observed signature. The 2D crustal models confirm crustal thicknesses and density to aid the interpretation of crustal type, particularly in the continent-ocean transition where the geophysical signature can help to understand the role of magmatism, hyperextension, or mantle exhumation.

Our tectonic model comprises a rigid, kinematic terrane reconstruction showing the evolution of geologically unique terranes through time, and a dynamic plate reconstruction constrained by geodynamically modelled plate boundaries. Rigid terranes in the model show the detailed tectonic evolution of the Western Mediterranean by reconstructing fault-bounded blocks using Euler rotations derived from geological and geophysical observations. Dynamic elements of the model show a bigger picture tectonic evolution including long and short-lived plates bounded by active tectonic boundaries. Together these elements illustrate the full tectonic evolution including rigid blocks, deforming margins and palaeo-oceanic domains.

We also present an attributed catalogue of tectono-thermal events, which describe the location, age and duration of key events that have occurred through time; visualisation of these events aims to assist with understanding the thermo-tectonic evolution of potential resource exploration targets and geothermal prospectivity.   

Paleogeographic and landscape evolution models are built alongside the tectonic model allowing iterative refinement of the models. Palaeogeographic interpretations include gross depositional environments, the cause and timing of uplifted and eroding areas, and likely lithologies in depositional areas. We build digital elevation models for each stage which are constrained by palaeogeographies and drainage networks. This palaeogeographic module therefore illustrates source-to-sink relationships, which is key for exploration across a range of energy sectors.

How to cite: Masterton, S., Webb, P., Hill, C., Galsworthy, A., Raynham, L., Wilson, L., and Leah, H.: Paleogeographic and tectonic models of the Western Mediterranean, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14780, https://doi.org/10.5194/egusphere-egu23-14780, 2023.

X2.166
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EGU23-17005
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ECS
DDE scholar report: a new open and Ai frontier and innovative reflect for solid earth 
Meng Wang, Yu Zhao, Mike Taylor, and li Cheng

The Deep-Time Digital Earth (DDE) program was initiated by the International Union of Geological Sciences (IUGS) and is being developed in cooperation with national geological surveys, professional associations, academic institutions and scientists around the world. Following the FAIR (findable, accessible, interoperable and reusable) and TRUST (Transparency, Responsibility, User focus, Sustainability and Technology) principles, DDE aims to link and harmonize global deep-time Earth data and share global geoscience knowledge with the goal of stimulating data-driven discoveries in the study of Earth's evolution through deep time.

In order to release DDE's expert knowledge bonus, data bonus and platform bonus, and help scientists deal with the challenges of earth science research based on their needs, DDE plans to launch a series of annual thematic, scholarly reports. Through in-depth analysis and interpretation of global research trends, it will help scientists understand major research breakthroughs in the field of solid earth sciences, and understand research methods, solutions to major scientific problems and highlight key topics and themes for future research.

The first DDE report is due to be released in 2023. DDE Report will use the theory and methods from bibliometric and altimetric research and release the “hot” topics and development of earth science research in solid earth science. The report will explore the deep reason behind trends and become the barometer of earth science research publications and outputs. DDE report aims to help scientists on determining the future research focus and innovation, and finally, to guide future earth science research trends.

How to cite: Wang, M., Zhao, Y., Taylor, M., and Cheng, L.: DDE scholar report: a new open and Ai frontier and innovative reflect for solid earth, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17005, https://doi.org/10.5194/egusphere-egu23-17005, 2023.

X2.167
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EGU23-17011
Updated digital paleogeography for East Tethys from Middle Permian to Middle Triassic 
Anqing Chen, Mingcai Hou, Qiang Ren, Mengxia Tang, Peng Ti, and Hanting Zhong

Deep-time geographic maps are the setting base of geological research and integrated windows for looking the past earth. Reconstructing paleogeography involves the evolution of the earth’s surface tectonic process, the pattern of land and sea, climate, and biology in geological history. To now, an advancing trend is developing digital paleogeographic model to replace the traditional maps. There already have been various global paleogeographic models based on digital softs, there is still a lack of intelligent or efficient tools for updating these paleogeographic models or creating new maps via integrating tectonic, lithofacies, paleontology, and paleoclimate data. In this study, a case study of the comprehensive paleogeographic reconstruction is carried out for the Middle Permian-Middle Triassic East Tethys, where is highly concerned and rich in geological data accumulation. The digital maps are reconstructed by the combination of automatic mapping with machine learning and manual correction. We use the newly upgraded paleomagnetic, geological and paleontological data to restore the paleoposition of the East Asian blocks at 260, 250 and 240 Ma, which shows the Paleo-Tethys Ocean (PTO) had a wider east-west range than the previous version due to a new paleolongitude of South China at 260 Ma through adopting the method of the Torsvik et al. (2008). Our model shows the multiple microblocks in the PTO were divided into north and south branches, which were semi-closed with several narrow seaways rather than total-closed at 260 Ma. Based on the newly lithofacies paleogeographic atlas of China and marine fossils data, we updated the surface landscape on our new block-pattern by developing a method of automatic mapping paleotopography with manual supervised machine learning.

How to cite: Chen, A., Hou, M., Ren, Q., Tang, M., Ti, P., and Zhong, H.: Updated digital paleogeography for East Tethys from Middle Permian to Middle Triassic, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17011, https://doi.org/10.5194/egusphere-egu23-17011, 2023.

X2.168
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EGU23-17417
DDE-TS: A semantic service for geologic time 
Chao Ma, James Ogg, Liangchen Zhou, Haipeng Li, Hongwei Wang, and Hongyi Zhao

Age is an important property in geologic data. It can tell us when a geologic event happened, how long did the event last. And it is important to know the sequence of events to consider the causation between these events. On the other hand, same set of data with different ages, paleogeographic data can be interpreted totally different. There are lots of geologic terms related to age: magnetostratigraphy (e.g. “Brunhes”), biostratigraphy (e.g. “Conosphaera”), lithostratigraphy (“Eagle Ford Formation”), geologic time concepts (“Cretaceous”), etc. This information are buried almost all geologic literatures. It is crucial to interpret these data as age. However, these geologic time data are heterogenous in literatures. For example, the age of “Cretaceous” in the literatures of year 1990 are different from that of year 2020, because the interpreted age of these concepts are evolving as techniques and the their studies are pushing the geologic time related terms being more accurate and precise. Thus, how to fast interpret the large amount of geologic time related terms are crucial for data mining in data-driven discovery of geoscience. Here we created a semantic service of geologic time related terms (age), named DDE-TS, which is supported by the Deep-time Digital Earth (DDE) program. This service includes knowledge graph of these geologic time related terms and tools to use this service. It can solve the problem of interoperability and reusability of geologic time related terms in literatures.

How to cite: Ma, C., Ogg, J., Zhou, L., Li, H., Wang, H., and Zhao, H.: DDE-TS: A semantic service for geologic time, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-17417, https://doi.org/10.5194/egusphere-egu23-17417, 2023.

Posters virtual: Fri, 28 Apr, 10:45–12:30 | vHall TS/EMRP

Chairpersons: Alexandre Pohl, Anta-Clarisse Sarr, Jonathon Leonard
vTE.3
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EGU23-933
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Matching mid-to-latest Carboniferous pole paths for eastern Australia and northern Armorica indicate a Pangea-B configuration and a latest Visean-Serpukhovian IITPW event 
Chris Klootwijk

A long and detailed pole path has been defined from Carboniferous ignimbritic successions across the Tamworth Belt forearc basin of a continental arc in the southern New England Orogen (SNEO) of eastern Australia. Stratigraphic successions spanning about 50 myr (~353 Ma to ~306 Ma) have been studied paleomagnetically over four decades, covering some  400 sites and 4500 samples. The Carboniferous SNEO pole path is thought representative for Australia and Gondwana. Its prominent south-over-east-to-north loop with mid Carboniferous apex differs fundamentally from conventional Australian and Gondwanan Carboniferous pole paths featuring south-over-west-to-north loops. The eastern loop of the SNEO path is supported by poles from other workers on the Tamworth Belt. The western loop of conventional paths may reflect unrecognised overprinting and alternative polarity interpretation. Mid-to-latest Carboniferous segments of the SNEO (south) pole path and of a Carboniferous-to-Permian pole path for the northern Variscan massifs of Armorica (AR), defined by Edel (Strasbourg) and co-workers and converted to south poles, are comparable in shape and length, each spanning more than a hundred degrees of arc. Euler pole matching of the two mid-to-latest Carboniferous segments, taken as representative for Gondwana (SNEO) and tentatively so for Laurussia (AR), locates Armorica off northwestern Gondwana, and with it Laurussia, in a Pangea-B configuration. The two mid-to-latest-Carboniferous segments are each bounded by prominent mid Carboniferous and latest Carboniferous-early Permian loops, likely reflecting global tectonic events, dating the Pangea-B configuration as lasting from the Sudetic phase to the Asturian phase of the Variscan Orogeny, with transformation to Pangea-A likely starting therefrom. Such a Pangean evolution offers new insights into location of a northern Gondwanan Armorican Spur, into heating-up of Pangean lithosphere as a cause for the late Carboniferous Hercynian Unconformity, and into latest Carboniferous-to-late Permian transformation of Pangea-B-to Pangea-A as a common driver for contemporaneous oroclinal deformation of the, Gondwanan-antipodal, Ibero-Armorican Arc and SNEO and also as a cause for early Permian Pangea-wide extension. Global movements described by the Carboniferous SNEO pole path and by the matching SNEO and AR mid-to-latest Carboniferous pole path segments suggest causality between a Visean northern excursion of Gondwana that likely disturbed the earth’s moment-of-inertia, a latest Visean-Serpukhovian Inertial Interchange True Polar Wander (IITPW) event that likely led to latest Visean-Serpukhovian onset of continental glaciation consolidating the Late Paleozoic Ice Age and to the Serpukhovian biodiversity crisis, and the Bashkirian start of the Permo-Carboniferous Reverse Superchron (PCRS) that may have eventuated from changes in heat flow across the core-mantle boundary brought on by IITPW repositioning of the Large Low Shear-wave Velocity Provinces and Ultra-Low Velocity Zones. Such a Variscan-IITPW-PCRS causal chain would constitute an order of magnitude faster (107 yr) top-down feedback between plate tectonics and the geodynamo than could be effectuated through mantle turnover.

How to cite: Klootwijk, C.: Matching mid-to-latest Carboniferous pole paths for eastern Australia and northern Armorica indicate a Pangea-B configuration and a latest Visean-Serpukhovian IITPW event, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-933, https://doi.org/10.5194/egusphere-egu23-933, 2023.

vTE.4
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EGU23-5574
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ECS
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Paleogeomorphic evolution in eastern North China controlled by the subsidence of the marginal sea shelf since late Cenozoic 
Xu Han, Yanhui Suo, Sanzhong Li, Xuesong Ding, Shuangshuang Song, Zihan Tian, and Xinjian Fu

Since the late Cenozoic, the geomorphology in the eastern part of North China have undergone tremendous changes under the influence of a variety of complex factors, but the exact process and finalization time are still controversial. The Badlands numerical simulation tool was used to dynamically reconstruct the geomorphic evolution process in eastern North China since the late Cenozoic (25 Ma). The  rationality of the simulation results was validated by comparing with  the regional tectonic framework and sedimentary distribution. The results show that the geomorphology in the eastern North China has been finalized and tends to evolve stably in Neogene, and is mainly controlled by tectonic activities. In addition, in the eastern part of North China during this period, there may be an ancient river - "East China River" around the Shandong Peninsula. It was formed no later than the Early Neogene, and may disappear during the Holocene. The results can provide quantitative basis for the study of geomorphic evolution and sedimentary process on the tectonic scale.

How to cite: Han, X., Suo, Y., Li, S., Ding, X., Song, S., Tian, Z., and Fu, X.: Paleogeomorphic evolution in eastern North China controlled by the subsidence of the marginal sea shelf since late Cenozoic, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5574, https://doi.org/10.5194/egusphere-egu23-5574, 2023.

vTE.5
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EGU23-5654
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ECS
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Dynamic evolution of Cretaceous Paleogreography and the eastward migration of the Jehol Biota in North China 
Shuangshuang Song, Yanhui Suo, Sanzhong Li, Xuesong Ding, Xu Han, Zihan Tian, and Xinjian Fu

Destruction of the North China Craton mainly occurred in the Cretaceous and has been in hot debate due to its important tectonic significance. It is suggested that the spatio-temporal evolution of the Jehol Biota in northeastern North China is driven by the North China Craton destruction during the Early Cretaceous, due to the abrupt changes in paleogeographic environment. However, little quantitative work on the dynamic paleogeographic evolution in North China has been done. In this study, using the paleosoil weathering indexes (PWI and CFXNa) and carbonate isotope, we reconstructed the paleo-elevation of North China at 145 Ma. Then, factors include tectonic movements, sedimentology, paleoclimate and sea level changes were quantitatively combined into the Badlands software, we modeled the Cretaceous dynamic paleogeomorphic evlution of North China. It is revealed the eastern North China experienced an abrupt geomorphological transition from the collapse of the paleo-plateau to the formation of the Bohai Bay Basin due to the subduction retreat of the paleo-Pacific Plate. The geomorphological transition led to the formation of a series of rifted basins that migrated eastward. The eastward migrating subsidence basin and eruption of volcanoes jointly controlled the eastward migration of the Jehol Biota.

How to cite: Song, S., Suo, Y., Li, S., Ding, X., Han, X., Tian, Z., and Fu, X.: Dynamic evolution of Cretaceous Paleogreography and the eastward migration of the Jehol Biota in North China, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5654, https://doi.org/10.5194/egusphere-egu23-5654, 2023.

vTE.6
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EGU23-5760
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ECS
Dynamic paleogeomorphic reconstruction revealing the incision process of the Three Gorges of the Yangtze River 
zihan Tian, Yanhui Suo, Sanzhong Li, Xuesong Ding, Xv Han, Shuangshuang Song, and Xinjian Fu

The Yangtze River is the largest river in Asia. It is an important geomorphological event in a united tectonics-climate-geomorphology system in Cenozoic era in China. The incision of the Three Gorges, which is located between the Sichuan and Jianghan basins, marked the formation of the modern Yangtze River. However, it is still controversial on the key scientific issue of "when the Three Gorges formed or was incised", due to the abundant geological data. The previous study usually focused on one factor affecting the river development, e.g., tectonic movements, sedimentology, paleoclimate and sea level changes, to conclude this key issue. Those key factors could be quantitatively combined into Badlands, a software that simulates the paleo-geomorphology. Take the area to the east of the "first bend" (Shek Kwu Town in Yunnan Province) of the Yangtze River as the study area, we used Badlands to reconstruct the geomorphology and river system evolution process since the Late Cretaceous (80Ma). Then the seismic data of Sichuan Basin and Jianghan Basin were used to test the reliability of our model results. The results revealed that the river flow direction in the Sichuan Basin was reversed to drain northwards due to the Late Eocene-Oligocene uplift in the eastern Tibet and the southwestern Upper Yangtze River. The Jianghan Basin had been in a low base level during the early Paleogene, controlled by the continental rifting environment in eastern China. The reversal of the drainage direction in the Sichuan Basin and the long-lasting low basal level in the Jianghan Basin eventually made the Three Gorges to be incised at the latest Oligocene. We proposed that the flow direction of the Upper Yangtze River was reversed and captured by the Middle Yangtze River is the incision mechanism of the Three Gorges.

How to cite: Tian, Z., Suo, Y., Li, S., Ding, X., Han, X., Song, S., and Fu, X.: Dynamic paleogeomorphic reconstruction revealing the incision process of the Three Gorges of the Yangtze River, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5760, https://doi.org/10.5194/egusphere-egu23-5760, 2023.