Following more than a decade during which the reality of Pannotia was widely accepted, the existence of this Ediacaran supercontinent has come into question. This is due largely to advancing geochronology, which suggests that the supposed landmass had begun to break up well before it was fully assembled. Paleomagnetic data from this time interval have been used to both support and refute the existence of Pannotia, but are notoriously equivocal, and proxy signals of Ediacaran-Cambrian supercontinent assembly and breakup, although collectively compelling, can be individually challenged. Efforts to detect the mantle legacy expected of supercontinent amalgamation, however, are more compelling, and support large-scale mantle upwelling in the wake of Pannotia assembly. So, irrespective of whether Pannotia was a supercontinent or not, its assembly appears to have influenced global mantle convection patterns in a manner consistent with one. In the context of the supercontinent cycle, the question of Pannotia’s existence is of fundamental importance since it is central to the nature, duration and evolution of the cycle, it dictates the cycle’s geodynamic pathway from the breakup of Rodinia to the assembly of Pangea and, more crucially, it queries whether a full-blown supercontinent is needed to drive the cycle from one iteration to the next.

The Variscan belt of western Europe is characterized by the deformation of an anomalously wide continental passive margin, located in northern Gondwana, that acted as the lower plate during the upper Devonian – Carboniferous Variscan collision. Another feature in this collisional belt are the unrooted “allochthonous complexes” with lower crust and mantle rocks associated with dismembered ophiolite-like rocks, classically interpreted as sutures of putative oceanic realms (Rheic and/or Paleo Tethys oceans).

Many models have been built in the past decades to explain the architecture of the Variscan belt, generally using oversimplified geometries for the passive margin. When continents break apart, the lithosphere is thinned by stretching and “necking” through time. In rifted margins, the lower and upper continental crust become coupled and embrittled, causing major faults (i.e. extensional detachments) to propagate into mantle depths, and leading to mantle uplift. This process, “hyperextension”, is increasingly documented worldwide in recent passive margins and it may also be accompanied by magmatic activity derived from the decompression of the lowermost crustal components or even the mantle.

Two episodes of partial melting in lower crustal and/or mantle rocks can be identified during the long-lived evolution of the northern Gondwana passive margin, during Ordovician and lower Devonian, and can be associated with the margin stretching linked to ridge subduction. Inversion of a complex hyperextended margin depicting key magmatic features may explain most of the characteristics that can be observed nowadays in the West European Variscan Belt, including the unrooted nature of the complexes.

During Ediacaran to earliest Cambrian times, the Cadomian Orogen was formed on the periphery of the Gondwana supercontinent. The orogenic belt was structured in the geotectonic style of the recent western Pacific region. Cadomian arcs and marginal basins aged at c. 570-538 Ma were linked to an intense recycling (remelting) of crustal units of the West African and the Sub-Sahara cratons. The existence of an Upper Ediacaran glacial period at c. 566-560 Ma places the origin of the Cadomian orogen in high latitudes of the southern hemisphere. Due detrital zircon populations from Cambrian strata the Cadomian orogen shared a part of its geotectonic history with East Avalonia. Because of the split-off of Avalonia from Gondwana mainland the Rheic ocean became opened. Provenance studies point to a docking of East Avalonia onto southern Baltica at c. 430 Ma and to a closure of the Rheic Ocean at c. 430-420 Ma. In the aftermath, the re-opening of a narrow Rhenish Seaway happened in mid-Devonian time. Deposits formed on the Rheno-Hercynian margin display sedimentary supply from southern Baltica, while most East Avalonian sources were buried and not available for erosion. Siliciclastic shelf deposits of Saxo-Thuringia were derived from Cadomia and its West African hinterland. As a result of the closure of the Rhenish Seaway the old suture of the Rheic Ocean was overprinted. Pangea´s internal suture is complex and became formed by closure of two oceanic basins and thus, forms a “cryptic” structure.

The geochemistry of sedimentary sequences allows the recognition of patterns and shifts in geodynamic settings. On active margins, the contribution of these sequences to arc magmatism through processes such as subduction erosion is being actively investigated. Thick sequences were sedimented along the Gondwana margin between the Ediacaran and Cambrian times. These preserve the evolution of their sources, which are closely related to the activity of arc systems and nearby continental areas. In the Variscan Belt, the SW Iberian Massif (Ossa-Morena Complex) preserves a section of an arc whose evolution is followed through the characterisation of subduction-related magmatism and the coeval metasedimentary record, during a time interval spanning almost 100 Ma. This study reveals that arc magmatism was linked to synorogenic sedimentation in a complex and poorly explored way. In this sense, arc recycling is shown by the isotopic (Nd) equivalence between the sedimentary series and the mafic magmatism related with subduction onset (pre- to 602 Ma) preserved in this section. Early magmatic pulses of arc building (c. 602-550 Ma) are characterised by their adakitic signature related to the melting of a significant volume of slab-induced sediments, probably favoured by subduction erosion. Meanwhile, during late stages (c. 540-534 Ma), magmatism evolved towards greater mantle input associated with the progressive variation of the slab angle. This study provides a model for the petrogenetic and geodynamic evolution of the arc from the Ediacaran to the early Cambrian times, improving the accuracy of future paleogeographic reconstructions.

The late Carboniferous–Early Triassic Krkonoše Piedmont Basin in the northern Bohemian Massif was initiated as a fault-controlled basin during the waning stages of the Variscan orogeny and its transition to an intra-plate setting. The basin was filled with 9 formations of mostly red beds with a total thickness more than 2000 m, deposition was accompanied by extensive volcanic activity dominated by andesitic lava flows and ash-flow and ash-fall tuffs. The U–Pb detrital zircon geochronology on 17 samples taken up-section across the basin stratigraphy points to local as well as distant sources of detritus derived predominantly from the nearby Saxothuringian and Teplá–Barrandian units, with Archean–Paleoproterozoic, Ediacaran, Cambro-Ordovician, Late Devonian and middle–late Carboniferous age peaks. Furthermore, magnetic fabric of the red beds was analysed at 29 sampling sites using the anisotropy of magnetic susceptibility (AMS) method in order to understand both the syn- and post-depositional history of the basin. Five different fabric types were detected across the basin and interpreted in terms of random orientation of magnetic grains due to turbulent flow (Type 1), strong alignment of magnetic minerals representing depositional fabric and recording paleocurrent directions (Type 2), superposition of compaction strain onto pre-existing depositional fabric (Type 3), tectonic fabric formed due to small increments of regional strain (Type 4), and an anomalous, mineralogy controlled inverse fabric (Type 5). Altogether the detrital zircon ages and multiple magnetic fabrics reveal a long term and complex sedimentary and post-sedimentary evolution and inversion of the basin in the Pangea interior.

Results of a systematic study are presented combining U-Pb ages, Hf isotope data and shape parameters (length, width, aspect ratios, roundness, roughness, typology) of detrital zircon populations from low- to medium-grade greywackes of the Badenweiler-Lenzkirch Zone (BLZ), which is squeezed between high-grade gneisses of the Central and Southern Black Forest Gneiss complexes. Nine sample are investigated from three formations: Sengalenkopfschist, Schleifenbachschist, and Protocanites Greywacke unit, assumed to be deposited from the Early Ordovician to Early Carboniferous based on biostratigraphic record. This interpretation, however, is at odds with detrital zircon U-Pb ages, revealing robust maximum depositional ages between 368 and 378 Ma for rocks of all three units. Age spectra show peaks at 380-400 Ma, 480-500 Ma, 600-620 Ma, 700-750 Ma, 0.9-1.1 Ga, 1.8-2.2 Ga, and 2.6 Ga, and Hf isotopes a juvenile input at 380-400 Ma (εHf_t up to +5). The combined age-Hf data point to a similar provenance like the metamorphic rocks exposed in Southern Black Forest gneiss complex, hosting relics of different Gondwana-derived terranes, in addition to a Late Devonian arc-back arc system. Similar proximal sources are also indicated by the finding of abundant euhedral zircon grains with ages <550 Ma in all samples, and a significant overlap in zircon typology. The low degree of zircon roundness and roughness reflect sediment transport in water-saturated media, but in some samples has been significantly modified by post-depositional structural-metamorphic overprint, causing mechanical zircon peeling and chemical dissolution in contact with sheet silicates, in particular during garnet-forming dehydration-reactions.

There is no firm evidence for glaciation for over 1.5 billion years, i.e. from the Great Oxidation Event (or Episode) until the onset of the Cryogenian Period. By contrast, global glaciation became the predominant climate state for the next 85 million years, followed by a series of regional ice ages that culminated in the Ediacaran-Cambrian biological radiations. There is increasing evidence that each of these climatic events was preceded by a negative carbon isotope anomaly, potentially caused by imbalance within the global sulphur cycle and related redox and productivity feedbacks. In this presentation, I aim to outline the evidence for primary carbon isotope anomalies before transitions into glaciation at c. 720 Ma, c. 660 Ma, c. 580 Ma and c. 560 Ma, as well as similar isotopic events that have identical geochemical context, but for which no glacial deposits have yet been identified. Cryogenian-to-Cambrian carbon cycle elasticity reflects a distinct earth system state, which was likely related to a dynamically changing organic carbon reservoir, oxidation of which was coupled to sulphate and ferric iron reduction. Organic carbon likely became the dominant redox (and climate) capacitor in the exogenic earth system only once atmospheric oxygen ceased to be a limiting factor for the weathering of iron sulphide minerals. The extent to which sulphur cycle imbalance forced climatic and environmental change after the Cambrian explosion remains to be determined.

The terminal Ediacaran Urusis Formation of the Nama Group (southern Namibia and northwestern South Africa) is a fossiliferous, mixed carbonate-siliciclastic succession with numerous silicified volcanic tuff interbeds. Studies of the Urusis Formation have historically focused on the Swartpunt area of southern Namibia, where post-depositional thrusting associated with the Gariep orogeny transported and emplaced the Formation as a series of thrust plates, which abut autochthonous Nama Group deposits to the east. Over thirty years of geochronological, chemostratigraphic and paleontological investigations have made the Swartpunt area a key reference section for terminal Ediacaran chronostratigraphy. Recent geochronological data from an expanded succession, exposed on the border between Namibia and South Africa, have cast doubt on the interpretation that ash beds in the vicinity of Swartpunt record depositional ages, possibly due to zircon reworking. The resulting implications for the temporal calibration of global terminal Ediacaran chemostratigraphy, as well as confidence in the maximum reported uncertainty of radioisotopic dates across geological time, are numerous. However, alternative regional structural complications that may resolve these issues have not yet been fully considered. Here, we build upon foundational observations of structural tectonics in the Swartpunt area, combining high resolution geological mapping, outcrop and drill core stratigraphy obtained through the ICDP GRIND-ECT project, carbonate carbon isotope (δ¹³C_carb) chemostratigraphy, and new high precision radioisotope geochronology (zircon U-Pb chemical abrasion-isotope dilution-thermal ionization mass spectrometry, CA-ID-TIMS). We use these data to explore structural alternatives that may resolve the chronostratigraphy of the Urusis Formation without invoking insidious zircon reworking.

Marine carbonates are potential archives of geochemical proxies, such as U-Pb and Sr isotopes, which can be utilized in the reconstruction of past climate conditions and ancient seawater composition. The ability to confidently reconstruct environmental conditions in the past times is of great importance since they are linked with changes in the biosphere. For example, the Ediacaran-Cambrian transition was a period of time where significant evolutionary change modified the biosphere. An intact, continuous record of environmental conditions will help to understand better the timing, nature and sequence of events that preceded or accompanied such changes in biodiversity. However, carbonate rocks are susceptible to numerous post-depositional processes (such as: oxidative weathering, diagenesis, burial, lithification, deformation, dissolution and reprecipitation), which may alter the geochemical record. Additionally, detrital components may increase the complexity of the geochemical signature and the carbonate composition.

Thus, we have to understand and identify the presence or absence of such processes, before extracting meaningful geological information from these archives. Laser Ablation – Inductively Coupled Plasma – Mass Spectrometry (LA-ICP-MS), is a tool that offers spatial resolution when performing geochemical analyses, which may help to interpret the geochemical data. Here, we combine observations from U-Pb and Sr isotopic systematics supported by trace element abundances to identify domains that are indicative of post-depositional processes, over protracted time and variable in their extent.

Neoproterozoic Nama Group sediments in SW Namibia provide an example of the interplay between the deposition of clastics and carbonates that do not obviously follow the “rules” of sequence stratigraphy. The unconformity surface beneath the sediments is planar and extensive. Basal interbedded carbonates and coarse clastics are overlain by a massive influx of fluvial clastics (Kliphoek Member). These fine upwards and are overlain by fine grained clastics with interbedded carbonates and minor turbidite sands (Aar Member) that contain most of the fossils found in this part of the Nama Group. Carbonate beds become more common towards the top of this member, which is overlain by a thick carbonate unit of region extent (Mooifontein Member).

Southwards the basal clastics (Kanies Member) become thicker, while carbonate beds in the overlying Mara Member are more dominant. The Kliphoek Member becomes finer grained but includes some coarse grained clastics, and the Aar Member contains more and thicker carbonate beds. Paleocurrents show a dominant sediment transport towards the west and southwest.

Questions posed by the stratigraphy include whether the basin subsided at a constant rate, where was the shoreline at any given time, where were the input points of the clastic sediments and how and why did the influx rate vary? Did changes in sea level, and therefore shoreline position, influence the deposition of carbonates, or was this mostly influenced by a lack of clastic influx? We do not have accurate ages for the sediments or the rate at which they were deposited.

The energy transition will require vast amounts of mineral raw materials. Only a small part of this demand is likely to be covered by recycling. A large part of the current discussion has therefore centered on the question whether the mining industry can provide sufficient supply in this critical period of global development. This lecture briefly examines the magnitude of this issue, and then discusses current research aiming to improve our foresight on future mineral supply. The examples of gallium and lithium will be used to illustrate the most important questions as well as potential solutions.

The wide range of chemical and isotopic signatures preserved in minerals of the apatite supergroup makes them truly useful across a broad spectrum of scientific applications, helping geoscientists to understand magmatic, metamorphic, paleoenvironmental, and (paleo)ecological processes. Ongoing progress in method developments has made secondary ion mass spectrometry (SIMS) one of the primary techniques for micro-scale apatite investigations. The ability to sample in situ picogram masses with SIMS allows for isotope studies of both rare and heterogenous samples. However, the availability and quality of reference materials (RMs) necessary for quantitative measurements has hobbled key applications.

Improvements of apatite isotope analysis method have been a major focus of our nearly decade-long initiative [1,2]. We are continuing our efforts to characterize RMs and advance SIMS measurement methodologies for sulfur, boron, oxygen, and U-Pb isotopes in apatite and related materials. By making use of existing mineral collections, we have been investigating the chemistry-dependent behavior of different samples under primary ion beams, along with the surface properties of polished mounts and calibration strategies. Such improvements in our fundamental understanding of these analyses will be crucial for future apatite research initiatives. Characterization studies devoted to the coming generation of apatite RMs have documented the challenges faced even by more traditional analytical techniques operating at much larger sampling scales.

References:

[1] Wudarska et al. (2021), Geostand Geoanal Res. doi:10.1111/ggr.12366.
[2] Wudarska et al. (2022), Geostand Geoanal Res. doi:10.1111/ggr.12416.

Acknowledgements: This research has been supported by the International Association of Geoanalysts (Geoanalytical Research and Networking Grants).

The fast and accurate on-site analysis of brines and ore leaching solutions is still a challenge. Conventionally used laboratory methods such as ICP-OES or ICP-MS are not suitable for on-site applications due to high plasma gas flow rates and power consumption. On the other hand, portable X-ray spectrometers are not able to analyse light elements such as Li, Na or K with adequate accuracy. Therefore, a fast and precise method combining on-site suitability and quantification of light elements would be preferable.

Here we investigated the potential of the Micro-Discharge Optical Emission Spectroscopy (µDOES) for the on-site and on-line analysis of lithium ore leaching solutions, whose industrial end product is an essential precursor for the battery industry. The technology is based on a micro-plasma, which is directly created inside the liquid sample without any carrier gas by applying high voltage pulses to electrodes enabling optical emission spectroscopy on-site^[1].

After parameter optimisation (conductivity, wavelength selection, discharge energy), on-line measurements of different process steps at a lithium hydroxide pilot plant were carried out. In addition to Li, other elements like Na, K, Ca, Mg or Rb were quantified. The technique demonstrated its capability for the fast and precise on-site analysis of major components and trace elements in saline solutions. Results showed good agreement with established laboratory methods, such as ICP-OES and ion chromatography.

[1] B. Wiggershaus, M. Jeskanen, A. Roos, C. Vogt and T. Laurila, Trace element analysis

in lithium matrices using Micro-Discharge Optical Emission Spectroscopy, J. Anal. At.
Spectrom., 2024. DOI:10.1039/D4JA00044G.

The purpose of this study was to investigate the chemical composition of red iron pigments based on waste iron sulfate. As a model waste, waste iron(II) sulfate from Grupa Azoty Zakłady Chemiczne POLICE S.A is used. Obtained pigments were also compared to commercially available materials from various manufacturers like BASF (Germany), Percheza (Czech Republic), Boruta-Zachem (Poland) or Edan (Poland).

Pigments were analyzed with several analytical methods like: X-Ray Diffraction, Dynamic Light Scattering, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, Helium Ion Microscopy and Scanning Electron Microscopy.

In determining the phase and chemical composition, we encounter some limitations of the methods. For example, during XRD analysis using Cu-Kα source, quartz-derived phases were visible in some commercial pigments. Comparing these results with FTIR analysis, the presence of quartz was confirmed, but in addition, vibrations from CaCO₃ were seen, which was not visible in XRD. Only by changing the radiation source in XRD to Co-Kα was it possible to detect phases originating from CaCO₃.

Precise knowledge of the contents of samples is frequently lacking prior to analysis. This is particularly true for external samples, which are frequently examined without prior information. Consequently, it is crucial to combine various analyses to obtain the most accurate results.

Although micro-XRF as an analytical technique was developed over 20 years ago, it is with the continuous advancement of computing and hardware technology that it has become more powerful than ever and a routine part of many geoscience characterization workflows. A principal reason for this is the systems capability to analyse large samples at micrometer scales with very minimal sample preparation. This flexibility makes the micro-XRF system ideal for analysing field samples (e.g., hand specimens, drill cores) in the laboratory, and thus easily and timeously enabling relevant decisions to be made about up- or down-scaling information or additional sample analysis in any given workflow. In addition, micro-XRF can analyse a range of sample sizes, from large specimens (over 10´s of centimeters) to those prepared as the commonly used polished thin sections or epoxy briquettes. Furthermore, results of micro-XRF analysis range from major, minor and trace elemental chemistry in semi- and fully-quantified form, to derived mineralogy, thus yielding data-rich information across a range of geoscience fields such as petrology, sedimentology, geochemistry, paleontology, economic geology, amongst others. The visualization of the elemental chemistry and mineralogy on such a large scale is extremely intuitive and relevant in geosciences, as it enables the user to directly link the sample’s visual structure to its chemistry. This presentation will review these capabilities in the world of geoscience and discuss the possibilities for the future.

µXRF is a versatile technique that has been used in various geoscientific fields, particularly for the mapping of larger hand specimen or drill cores. It is easy to use, non-destructive and requires only little sample preparation, enabling the acquisition of 2D element distribution and mineral identification via EDX spectra. However, a limitation is the diffraction of the X-ray beam by the crystal lattice, which can produce peaks that overlap with actual element peaks, thereby affecting chemical quantification and mineral identification. Previous research, such as Nikonow et al. (2016), has demonstrated methods to eliminate these diffraction peaks from µXRF spectra. Additionally, diffraction can be used to identify individual grains within a mono-mineralic domain, such as quartz, without the need for thin section preparation. Since diffraction depends on the angle between the crystal lattice and the X-ray beam, differently oriented grains will produce diffraction peaks at different energies in the spectrum and can be distinguished from each other in the energy-dispersive µXRF spectrum. This technique enables not only the identification of optically similar minerals in the drill core (e.g. magnetite and ilmenite), but also the extraction of grain shapes and measurement of their 2D size, area, and orientation in the cutting plane and allows for quantitative textural analysis, helping to understand e.g. igneous processes (Higgins 1998). The application of this method is demonstrated on drill core sections from magnetitite layers of the Upper Zone of the Bushveld Igneous Complex, South Africa.

Micro X-ray Fluorescence (MXRF) spectrometers enable non-destructive and elemental analysis of a wide variety of solid samples with a lateral resolution of a few tens of micrometers using focusing optics. Confocal MXRF (CMXRF) offers additional depth-dependent measure­ment capabilities, based on a three-dimensional probing volume created by the confocal ar­rangement of a focusing lens in the excitation and detection channel. Therefore, CMXRF pro­vides micro-scalic resolved measurements of complete sample volumes by depth profiles (1D), cross section mappings (2D) and stacked element distribution images (3D). The strengths, challenges and potential of a modified (confocal) MXRF tabletop spectrometer for non-destruc­tive and depth-sensitive element analysis will be illustrated by geoanalytical and geo-related appli­cations:

The first application is the three-dimensional analysis of mineral inclusions. The sophisticated compositional studies and identification of mineral phases by CMXRF provides micro-scalic resolutions with certain limitations due to X-ray absorption, but also preserves the integrity of isolated inclusions for further analysis.

Another example is the study of biomineralization products, due to the biomimetic behavior of deep-sea sponges under extreme conditions resulting in the formation of novel three-dimen­sional composites. Several mineralization products such as atacamite, goethite and lepido­crocite have been studied by three-dimensional reconstruction of the elemental distribution of the formed composites.

The third application is the depth-sensitive analysis of the elemental composition of ce­ment stone corrosion zones simulating the acidic chemical attack on concrete samples. The interest in describing those corrosion processes is motivated by defining the occurring kinetics and deriving information about the persistence, strength and durability of concrete.

Micro-X-ray fluorescence spectroscopy (XRF) represents a well-established and complementary analytical technique to electron beam energy dispersive spectroscopy (EDS) for the detailed characterization of elemental composition in samples. The integration of the X-ray source (namely XTrace) facilitates the application of XRF technology within a scanning electron microscope (SEM). Micro-XRF excitation analysis is a specialized small-area/volume technique, particularly suitable for beam-sensitive samples due to the absence of charging effects. The technique offers significant advantages, including enhanced sensitivity for trace element detection, the capability to excite higher energy X-ray lines (spanning a full spectral range to 40 keV), and the acquisition of information from greater sample depths even in centimeter level.

The deployment of advanced X-ray polycapillary optics enables the focal spot size of the X-rays to be reduced to 10 microns, all within an X-ray source compatible with SEM ports. X-ray energy detection is performed using the existing EDS detector integrated into the SEM system. Consequently, the SEM system attains dual-source capability, encompassing both electron and X-ray sources (as illustrated in Fig. 1), thereby expanding the possibilities for material characterization. This dual-source capability is termed "Full Range EDS," leveraging the novel analytical potential arising from the combined dual excitation of micro-XRF and electron beam sources alongside an EDS detector. This dual-beam system, allowing samples to interact with either the SEM's electron beam, the XTrace’s X-ray photons, or both simultaneously. Full Range EDS confers numerous advantages over traditional EDS, providing researchers with deeper insights into the elemental and compositional intricacies of their samples.

Brandenburg’s surface geology predominantly consists of Quaternary sediments, with sequences averaging 50 to 80 meters (locally up to 500 meters) in thickness. Research up to 2008 on heavy mineral composition facilitated the lithostratigraphic classification of fluvial deposits, revealing frequency and compositional variations. Stratigraphic classification in Brandenburg relies primarily on pollen analysis of interglacial, predominantly limnic deposits, and small-scale gravel counts of (glacio-)fluvial and till sediments, leaving sandy components unrepresented methodologically.

To establish a comprehensive provenance analysis, the method development presented here includes both the heavy and light mineral fractions. The geochemical composition of the samples is determined semi-quantitatively using spectral analysis. In this project, 24 sand samples from the drill core Kb Borgisdorf 1/06 were examined to reconstruct the distribution patterns of Saale Late Glacial to Weichsel Early Glacial sediments in Brandenburg. The focus of method development is on sand deposits that cannot be classified by pollen and clast analysis. All samples were prepared for both polarization microscopy and Mineral Liberation Analysis (MLA), maintaining a grain size range of <200 μm. This saves time and provides a comprehensive dataset that is better comparable with conventional analyses. The data produced by the MLA are compiled into large databases and statistically analyzed, utilizing mineralogy and grain parameters such as size, length, width, and roundness. By comparing with comprehensive geochemical and mineralogical data, the method was validated. Initial results show that additional preparation yields comparable results and that samples without density separation are statistically reliable for heavy mineral analysis.

Elemental overview of a thin section (2.5 x 2 cm) typically requires large-area mapping over numerous fields, which can take several hours with conventional approaches. To shorten the measurement time without compromising data quality, we utilize the annular EDS FlatQUAD detector, capable of collecting up to 2.4 million counts per second. This speed reduces the required time-per-pixel, dwell time per frame, and overall measurement time, enabling the mapping of major elemental distributions across an entire thin section in under a minute.

In this example of a garnet-spinel peridotite from South Africa, we compare measurements of the entire thin section which took several hours to cover the 8 x 14 fields, resulting in high statistical accuracy compared with ultra-high-speed mappings revealing elemental distribution in less than one minute measurement time for the entire thin section. This example showcases the efficiency and capability of advanced EDS technology in geological studies. Extending the measurement time will result in much better statistics, and the software can detect mineral phases automatically; however, the major elements distribution is clearly visible in a short analytical run time for the entire thin section, including offline extraction of spectra from each pixel in the map for further quantification.

Geosciences represent one of the most diverse fields of research and therefore provide a superb opportunity to study the complex Earth System, offering manifold perspectives and links to connect with other disciplines. Are we fully exploiting this potential, especially seen the role of geosciences for society, interdisciplinary research and international collaboration?

In my talk, I would like to emphasize on the relevance of geoscience for society by (1) informing the future about, for example, the bandwidth of prospective future changes in key parameters of the Earth System such as, for example, temperature and sea level rise, (2) highlight the potential of Geoscience for collaboration within the Earth-Environment-Human System by providing examples from current and ongoing research, combining, for example, approaches from natural and social science, as well as between scientific and local knowledge, and (3) discuss how we can better support innovative research and cooperation.

The Late Cretaceous collision of the Adriatic microplate with Eurasia led to a predominantly southwest-vergent and in-sequence structural architecture in the Dinarides. During the Paleogene, the deformation front migrated from the Internal to the External Dinarides, resulting in about 130 km of crustal shortening. Fault kinematic data and balanced cross-sections across the External Dinarides reveal contrasting deformation styles along the orogen, separated by a roughly 250 km-long dextral transpressive fault. This fault marks the changes from the southern, southwest-vergent nappe stack segment to the northern, northeast-vergent backthrust-dominated Velebit segment. These backthrusts originated at lateral facies boundaries associated with extensional Mesozoic half grabens.

The contemporaneous deformation of these two domains, indicated by the distribution of flexural foreland basin sediments, marked the end of the Paleogene Dinaric orogeny. Within these Eocene to early Oligocene syntectonic and older Mesozoic carbonate platform rocks, horizontal marine terraces are preserved at elevations of up to 600 meters. Using digital elevation models (DEMs), we extracted terrace surfaces along the Adriatic coast, ranging from Istria in the north to Montenegro in the south. All these flat surfaces are degradational, unrelated to bedding or faults, and located between the present-day Adriatic shoreline and the drainage divide. The area of the extracted marine terraces corelates with a reported positive P-wave tomography anomaly. Based on the reported thinned Adriatic lithosphere beneath the internal part of the orogen, our findings suggest that the Dinarides underwent widespread surface uplift in the Miocene due to mantle delamination with limited Neogene crustal shortening.

The Fichtelgebirge is located between the western edge of the NE-SW striking Eger Rift Zone and the Franconian Lineament. The basement mainly consists of late Variscan granitoids, Paleozoic meta-sedimentary rocks and meta-magmatites. Tertiary sediments are limited to isolated occurrences and basaltic rocks occur mainly along isolated outcrops that are located roughly in NE-direction. However, our current knowledge of the structural inventory of the rocks is limited and the interrelations of fault activity, reactivation potential, volcanism and uplift are not yet fully understood.

In order to improve the understanding of the structural history of the Fichtelgebirge, the orientations and kinematics of 193 fault planes were measured. The results show that most faults strike NNW-SSE, while only a minor number strikes in conjugated directions. Based on the field studies, a detailed paleo-stress analysis of the faults has been carried out and four different stress regimes could be identified: (i) Permo-Carboniferous NNW-SSE compression, (ii) a Late Cretaceous NE-SW compression and (iii) a presumably Neogene NW-SE compression with (iv) a contemporaneous or subsequent NE-SW extension. The first regime created pathways for the ascent of differentiated melts during the Late Carboniferous and Early Permian. The other stress regimes are interpreted to have played a significant role in the Cenozoic uplift of the Steinwald and other mountain ranges in the region by reactivating pre-existing fault systems. It is assumed that faults in the Fichtelgebirge, such as the nearby active Mariánské Lázne fault, carry a significant reactivation potential in the currently NW-SE orientated prevailing compressional regime.

The Pamir-Tian Shan-Hindu Kush orogenic segment at the western edge of the India-Asia collision stands high, reaches deep, transitions from flat to rugged, deforms truly 3D, and stretches wide beyond the direct continental collision zone. Based on data from a cornucopia of geoscience disciplines, we show that mantle driving forces and distinct geometrical and rheological boundary conditions govern the tectonic evolution, i.e., the mantle-crust-surface and hinterland-foreland interactions. We will take the subduction of marginal Indian lithosphere underneath the Hindu Kush and the indentation of the Indian cratonic mantle lithosphere into Asian (Tajik-Tarim) lithosphere since 10-13 Ma as an example for processes in the mantle. We show what effects they have on the deep Pamir crust, the Afghan-Tajik foreland basin, and the Tian Shan; those effects are lithospheric foundering below the Pamir, gravitational spreading of the Pamir-plateau lithosphere, Afghan-Tajik foreland-basin inversion, rise of the modern Tian Shan, and Fergana and Tarim block rotation. Our dataset integrates observations from seismology, petrology, petrochronology, thermochronology, and structural geology.

A structural description of the intra-montane basins establishes the deformation field of the southwestern Tian Shan that faces the Pamir and the Afghan-Tajik Basin and thus the Indian mantle indenter beneath the Pamir and the deformation it imposes—northward indentation and westward crustal collapse. Six major Cenozoic faults traceable over >100 km separate rigid basement blocks; tight synclines occupy their footwalls. These ~E-striking faults reactivate Paleozoic ones, indicate ~N-S shortening with a dextral strike-slip component, connect with ~WNW-striking ones with a strong dextral component, and ~ENE-striking ones confined to the western southwestern Tian Shan. The deformation field resembles that in the Afghan-Tajik Basin fold-thrust belt, and mimics in shape the geometry of the intermediate-depth earthquake zone beneath the Pamir. We infer that the southwestern Tian Shan is involved in the northward motion and westward collapse. The basement-rooted Cenozoic faults require a detachment underlying the southwestern Tian Shan, which should root in the delamination zone beneath the Pamir; a depth of the detachment at the brittle-ductile transition is consistent with the regular spacing of the intra-montane basins. A crustal-scale cross section connects the southwestern Tian Shan, the Afghan-Tajik Basin fold-thrust belt, and the delamination zone, and highlights the evaporite-detachment below the Afghan-Tajik Basin, the mid-crustal detachment below the southwestern Tian Shan, and the rooting of faults of the Afghan-Tajik Basin fold-thrust in the deeper detachment; this may run along the Moho.

The transition from subduction to collision marks a pivotal geological transformation as tectonic plates cease their subduction, giving rise to intense collisions that reshape landscapes and foster the creation of mountain ranges. We use thermo-mechanical numerical modeling to address the dynamics of continental margin subduction and the subsequent transition to collision.

Several collision orogens like the Alps document a typical series of events that are not fully understood:

1. Continental high-pressure (HP) units are formed from upper crust and only during early continental subduction. In a mature collision orogen continental upper crust is detached from lower crust at shallow levels, while lower crust might continue to subduct.

2. These units are rapidly exhumed along the subduction boundary and their final position in the orogen is “in-sequence” on top of the continental nappes and below the oceanic suture. Continental HP-units are sandwiched between units that experienced considerably lower peak pressures.

3. Rapid exhumation of HP units is followed by:

3.1 apparently extensional deformation, of which at least the final stage affects the entire nappe pile;

3.2 a phase of magmatic activity, i.e. the formation of granodioritic and tonalitic intrusions that cut the established nappe pile;

3.2 rapid rise of topography in the orogen.

In order to investigate this sequence of events and recognize factors controlling their timings and necessary conditions we reconstruct transition from subduction to collision with forward modeling. Here, we employ visco-elasto-plastic thermomechanical modeling approach to model subduction process followed by collision.

Since the first applications in the geosciences (~ 1985) and the first successful dating of zircons (1993, 1995), LA-ICP-MS has become a standard method for the analysis of major and trace elements as well as numerous isotope systems (e.g., Li, B, Sr, Sm-Nd, Lu-Hf, U-Th-Pb) in minerals, glasses and other solids.

Speed, relatively low cost, versatility, high spatial resolution (10-50 µm) and sufficient to better precision often make LA-ICPMS superior to competing methods. The most successful application, U-Th-Pb zircon geochronology has led to an exponential increase in scientific publications in this field between 2000 and 2020.

This article aims to give an overview of the developments of the last 10 years in the field of U-Pb dating of carbonates, garnets, sulphates, as well as various oxide and other silicate minerals. The complexity of the analysis, problems, the possible potential of these methods and the precision, accuracy and significance of the dates/ages compared to those of zircons are discussed.

What are the methodological challenges of the near future? Will methodological developments in LA-ICP-MS analysis be driven by technical advancements in analytical equipment or active science teams?

In-situ Rb-Sr dating using laser ablation (LA) systems coupled to inductively coupled plasma (ICP) – reaction cell mass spectrometers (MS/MS) is an emerging geochronological tool. This analytical setup uses reaction gases to allow the reaction of targeted masses. ⁸⁷Rb and ⁸⁷Sr can for example be separated chemically to avoid the isobaric overlap during mass-spectrometric analysis. In-situ Rb-Sr LA-ICP-MS/MS dating has until now successfully been applied to date magmatic, metamorphic and tectonic events as well as ore formation processes. In addition, it has huge potential for sedimentology and stratigraphy.

Here, we present case studies of in-situ Rb-Sr LA-ICP-MS/MS dating of detrital minerals (mica and feldspar) and glauconite. We focus on (1) the analytical routine, (2) data reduction and age calculation strategy and (3) interpretation of in-situ Rb-Sr age data. In addition, we demonstrate advantages of volume-coupled major and trace element data collected from the same laser spots. This data can for example be used as indicator of alteration and as multi-proxy tool for provenance studies.

The number of zircon age studies being published from all regions of the planet is consistently growing, as is for continental or global zircon ages databases. Unfortunately, a considerable amount of such data is often not utilized for future studies after their publication. Consequently, there is a considerable amount of valuable data that is waiting to be discovered for further use that could reach much further than reconstructing supercontinent cycles. An initial compilation of pre-Mesozoic zircon age data (N>5000, n>275000) characterizes the circum-Atlantic (s.l.) zircon provinces. Despite having compiled an initial zircon age database, further effort is necessary to reach the required sample density for mapping the age spectra of (meta)igneous host rocks and primary sediment flux in appropriate statistical, spatial and temporal frameworks. Nonetheless, this is a primary goal that will allow for more precise palaeogeographic reconstructions of terrane configurations in conjunction with additional data. To date, the zircon age database permits the identification of the primary zircon provinces and some sub-provinces at a reasonable terrane-scale resolution. The database also identifies distinct zircon age populations that can be used as "unique identifiers", e.g. to distinguish the western and the eastern parts of Cadomia or the role of the Kunene Intrusive Complex in southern Africa. Additionally, the presented compilation outlines the key zircon age provinces in large parts of the circum-Atlantic. Therefore, this study aims to present an initial impression of typical zircon age patterns found in the aforementioned areas at certain periods of time.

The erosional debris of the poorly exposed Paleo- and Mesoproterozoic mobile belts of Amazonia (Terra Amazonica Orogen, 2-1 Ga, TAO-1) eventually accumulated in the orogenic basins of the central proto-Andean Terra Australis Orogen (TAO-2, 0.65-0.2 Ga), offering an abundant indirect source of information.

From newly constructed U-Pb, Hf and O isotope zircon data bases we derived that in TAO-1 eHf(t) values define 3 cycles between 2-1 Ga from strongly unradiogenic to radiogenic values. After the dispersal of Rodinia, TAO-2 registers one large similar cycle. In accretionary orogens, such trends indicate the progressive removal of lower crust and lithospheric mantle of the upper plate during subduction and their replacement by new radiogenic crust.

d¹⁸O data show a flat d¹⁸O trend at 6.3‰ over the first 800 Myr of TAO-1, increasing to elevated values around 7.3‰ during collision with Laurentia. Contrastingly, d¹⁸O of TAO-2 trends from 8‰ to more mantle-like values just below 7‰. The different trends show that anatectic intracrustal recycling played only a subordinate role in the generation of new crust during TAO-1. However, there is a correspondence between the O and Hf isotope trends in TAO-2 towards more juvenile compositions through time.

Global d¹⁸O data showed gradually increasing d¹⁸O after 2.5 Ga indicating the progressive hydration and intracrustal recycling of the continental crust after the Archean. Our data register the sudden appearance of d¹⁸O values up to 10‰ at the Archean-Proterozoic transition indicating that Amazonia had experienced intracrustal recycling at an accretionary margin already in the Late Archean.

The Rosenhof Member is part of the Lower Cambrian Fish River Subgroup of the Nama Group in southern Namibia (Groß Aub Formation). The sediments of the Nama Group are deposited in two basins, the northern Zaris Subbasin and the southern Witpütz Subbasin. Both are separated by the Osis Arch, a basement updoming (Germs, 1974; Grotzinger and Miller, 2008). While the basal two Nama subgroups are influenced by these two basins and their paleorelief, the uppermost Fish River Subgroup sediments overstep the Osis Arch and cover previous deposits with an unconformity. Deposits of the Fish River Subgroup are represented by Lower Cambrian shales and sandstones (e.g. Grotzinger and Miller, 2008).

The sandstones of the Rosenhof Member show distinct sedimentary patterns that allow the interpretation as fluvial deposits originating from the north (e.g. Geyer, 2005). They were deposited after the final collision of the Kalahari Craton (south) and the Congo Craton (north) that created the Damara Orogen. The latter is discussed as a major sedimentary source area for the studied deposits covering southern Namibia (Kalahari Craton). For this purpose, the Rosenhof Member was sampled and studied at various locations, covering occurrences from its northern outcrops until its most southern ones. This sample set allows the study of changes in the sedimentary pattern of a particular member over an area of about 300 km.

This talk presents sedimentary structures combined with heavy mineral analyses (U-Pb on zircon and apatite) and discusses possible sedimentary source areas, as well as sedimentary mixing and homogenisation.

Faults act as conduits for large-scale fluid movements, often hosting multiple circulation events within their brecciated structures.

In the Alps, particularly along the Penninic Frontal Thrust within the ‘Briançonnais Zone’, a mineral assemblage of calcite and hematite has been observed in the breccias of the High-Durance normal Fault System (HDFS). Recent geological investigations have utilized a multidisciplinary approach, including petrological analysis, geochemical examination of calcite (involving stable isotopes and clumped isotopes analysis), and U-Th-Pb dating.

U-Pb dating on calcite provided dates ranging from 5.3 to 2.3 Ma and Hematite (U-Th)/He dating from 13.3 to 0.2 Ma. All ages indicates the onset of transtensional fault activation and the transition from the previous compressional tectonic regime in the Middle Miocene with a westward migration of the extension. The onset of the HDFS extensional regime thus appears to be contemporaneous with the development of the fold and thrust belt of the western Alpine foreland.

Two isotopic signatures (Δ₄₇) of the calcites suggest an open fluid system with (1) crystallization temperatures around 130°C related to deep fluids and (2) a meteoric fluid signature (36°C) associated to a 1900m precipitation altitude, indicating that similar altitudes were present around 2 My ago. This coincides with the transition from a Mediterranean climate to a colder, glacier-dominated climate, leading to valley formation during this period.

Upper Neoproterozoic sedimentary rocks anchored in the literature as greywackes are exposed in Saxo-Thuringia and represent the main sedimentary part of the Cadomian basement of the region with sedimentation ages between 540 and 570 Ma based on the youngest detrital zircon ages (e.g., Linnemann et al. 2000, Geol. Soc. Spec. Publ., 179, 131–153). Previous Nd model ages give a uniform old cratonic source of 1.5–1.9 Ga for the Neoproterozoic greywackes (Linnemann & Romer 2002, Tectonophysics, 352, 33–64). This study aims to re-examine the Cadomian greywackes of Saxony and adjacent areas by combining analytical methods, such as whole-rock Sm–Nd isotopic studies and detrital zircon U–Pb dating using LA-ICP-MS. The investigations have also been carried out comprehensively at locations not previously studied. Some Carboniferous greywackes were also sampled as a reference due to their similar appearance in the field and local uncertainties in their stratigraphic position. The new data are used to validate existing models of basin development and sedimentary provenance. The sedimentation of a large part of the Saxo-Thuringian clastic rocks along the periphery of Gondwana adjacent to the West African Craton in the Late Neoproterozoic could be proven. However, the youngest detrital zircons of around 490 Ma indicate that some units were deposited during the Late Cambrian to Early Ordovician and do not belong to the Cadomian rock units. Carboniferous samples show in addition Late Devonian zircon ages and Nd model ages younger than 1.5 Ga which points toward a different sedimentary provenance.

This talk presents radiometric ages and mineral sizes of detrital zircons and apatites representing six sediment samples from three different recent rivers of the eastern Erzgebirge: The Wilde Weißeritz, the Freiberger Mulde and the Müglitz. We took one sample from the upper and one from the lower reaches of each river.

The objectives were, (1) to find evidence for thermal, magmatic events in the apatites, (2) to record the U-Pb-spectrum of zircons for each sample, and (3) to improve insight into the transport behaviour and sediment composition of the studied rivers.

The apatites showed thermal overprinting of their U-Pb ages, which varied between ca. 306 Ma and ca. 328 Ma. Therefore, small, local thermal events seem to be more likely than one large event affecting the entire study area. The older ages are interpreted to represent the end of the Variscan Orogeny and the beginning of the post-Variscan magmatism. The younger ages are interpreted as later thermal overprinting by local magmatic events, possibly caused by heating events along the margins of the Erzgebirge Block at the beginning of the Permian magmatism.

The U-Pb-ages of the zircons represent the rocks of the hinterland of the specific rivers and show mainly Cadomian ages derived from the gneisses combined with (post-)Variscan ages from the igneous rocks. Therefore, the spectrum of zircons found at the sampling sites is dominated by the local rocks.

Interestingly, the detrital minerals analysed do not allow interpretation of very long sedimentary fluvial transport.

Recently, new age data have been published for the Variscan magmatism as well as for times of ore formation in the Erzgebirge (e.g., Breitkreuz et al., 2021; Burisch et al., 2019; Meyer et al., 2024; Leopardi et al., 2023; Löcse et al., 2020; Reinhardt et al., 2022; Tichomirowa et al. 2019, 2022). Förster and Romer (2010) wrote in their compilation on Carboniferous Magmatism that two major periods of magmatic activity occurred in the Erzgebirge. During the first period (327 - 318 Ma) most of the large plutons in the Western Erzgebirge were formed and probably also the volcano-plutonic rocks of the Altenberg-Teplice Caldera (ATVC) in the Eastern Erzgebirge (Förster and Romer, 2010). The second major period of magmatic activity was assigned by these authors to small subsurface granites and various subvolcanic rhyolithic dykes and microgranites (305 – 295 Ma). New high-precision dating of the major plutons in the Western Erzgebirge slightly shifted the proposed time interval for the first magmatic period (323-314 Ma; Tichomirowa et al., 2019). Based on new high-precision ages it was shown that the magmatic activity in the Western and Eastern Erzgebirge was diachronic and that the first volcanites in the Eastern Erzgebirge were already formed at ca. 322 Ma (Tichomirowa et al., 2022). We present new high precision age data for the second magmatic period from the Western and Eastern Erzgebirge and compare the age data of Variscan magmatic activity with the data for ore formation.

The early post-Variscan evolution of central Europe was characterized by the formation of numerous volcano-sedimentary Rotliegend (Late Carboniferous–early Permian) basins. Recent dating attempts in the Thuringian Forest Basin have shown that the precision and accuracy of zircon CA-ID-TIMS dating (< 0.1 %) is crucial to discriminate the sedimentation ages of successive formations. The correlation between different basins will be most successful by a combination of high-precision age dating with the existing extensive knowledge about biostratigraphic correlations.

Here, we present new zircon U-Pb CA-ID-TIMS data of three volcanic rocks from the Unkersdorf, Niederhäslich, and Bannewitz formations of the Döhlen Basin (Saxony, Germany) and of two tuff samples of the Manebach and the Goldlauter formations of the Thuringian Forest Basin (Thuringia, Germany). Our data indicate that all four formations of the Döhlen Basin were deposited during ≤ 1.8 Myr and are within errors coeval with the Manebach and Goldlauter formations of the Thuringian Forest Basin. The Niederhäslich Formation of the Döhlen Basin and the Manebach and Goldlauter formations of the Thuringian Forest Basin contain fossil-rich lacustrine horizons, which have been correlated to a variety of formations in other European basins through the use of insect, amphibian, or conchostracan assemblage zones. Our new data thus provide new absolute age constraints for different fossil assemblage zones, and thereby can be extrapolated to other basins in central Europe.

The Graissessac-Lodève Basin (southern France) contains a thick and very well preserved record of Late Carboniferous to Permian continental sediments. These sediments are remnants of a complex erosional history of the Variscan orogen and post-orogenic extension, as well as a record of the local geotectonic history of southern France. The use of original isotopic detrital zircon and apatite data revealed the provenance of the siliciclastic strata. The detrital zircon age populations and sandstone compositions in the Permian strata, which reflect the rapid exhumation and unroofing of the Montagne Noire dome, are determined by the ages and compositions of units forming the Montagne Noire metamorphic core complex to the west of the basin. The Cambrian to Archean zircon ages are most likely recycled detritus derived from the Early Paleozoic sedimentary cover and Neoproterozoic to Early Cambrian shales that formerly covered the Montagne Noire dome. Ordovician detrital zircon ages may indicate orthogneiss units of the dome. The youngest detrital zircon suite, ranging in age from ca 285 to 320 Ma, reflects erosional products of Carboniferous to Permian granites of the Montagne Noire axial zone. The latter zircon population is absent from Carboniferous-aged strata, but was found throughout the studied Permian strata. These results suggest that the young granite suite was exposed during early Permian time, reflecting uplift of the southern Montagne Noire during post-orogenic extension. Detrital apatite data from the Permian strata show that the last thermal event in the hinterland of the Graissessac-Lodève basin occurred in the Upper Carboniferous.

Global population growth and prosperity will result in increased raw material- and energy consumption. Countries such as China, India and Russia likely achieve today’s European living standards and related raw material and energy consumption by 2060. OECD (2019) states that the extraction of ores will likely increase globally from 2.6 Gt (1970) and 9 Gt (2019) to 20 Gt (2020), which cannot be covered by recycling alone. In addition, the German energy transition requires additional raw materials, black-start capable gas power plants, large underground energy storage sites and energy imports, aimed to balance fluctuating wind- and solar energy, among others, and replace the current 77% primary energy derived from gas, oil and coal. The responsible use of the geological subsurface for the extraction of raw materials and energy as well as energy storage locally and abroad is thus essential for a success of the planned German energy transition “Climate neutrality 2045" announced by the Federal Government (2021), aimed to counteract anthropogenic climate change. While Germany imports metals and energy and continuously loses applied know how of mining and refining industry being offshored, China, India, South Korea, Japan and the USA are pursuing different strategies to keep know-how and secure supply chains. The subsurface storage of CO2 (CCS) has been implemented by neighboring countries such as Norway and Denmark to reduce emissions, while the technology is still being discussed in Germany. This contribution discusses some challenges of energy- and raw materials supply, driven by increased anthropogenic climate change and environmental footprint.

Quantifying the feedbacks between tectonic processes in the lithosphere and climatic processes in the atmosphere is an overarching goal in Earth-Systems research. Long-term cooling during the Cenozoic has been linked to the growth of mountain belts, which enhanced erosion, chemical weathering, organic-carbon burial and drawdown of atmospheric CO₂. Conversely, it has been proposed that the cooler and more variable climate of the late Cenozoic led to increased topographic relief and erosion. However, the topographic and erosional response of mountainous topography to late-Cenozoic climatic cooling culminating in Quaternary glaciations, and the potential couplings between these processes, remain poorly constrained. Advancing our understanding requires the development of tools that record erosion rates and topographic relief changes with higher spatial and temporal resolution than the current state-of-the-art, and the integration of newly obtained data into next-generation numerical models that link observed erosion-rate and relief histories to potential driving mechanisms. Within the ERC-funded COOLER project, we are building a new ⁴He/³He thermochronology lab in Potsdam, developing numerical modelling tools that incorporate the latest insights in kinetics of thermochronological systems to make sample-specific predictions, coupling these tools to glacial landscape-evolution models to enable modelling of real landscapes with real thermochronology data as constraints and, finally, studying potential couplings between glacial erosion, relief development, and tectonics in selected field areas.

Species richness of Madagascar is uneven, with the highest species richness and endemism found on the steep great escarpment of the eastern margin. The unevenness is further observed within the escarpment region in that phylogenic turnover shows both latitudinal and altitudinal variations. Madagascar has remained almost tectonically inactive since the last rifting with Seychelles-India such that the fundamental topographic framework has been in place since Cretaceous. The high diversity and endemism of Madagascar challenge the conventional notion of uplift-driven speciation, which argues that speciation is driven by the formation of diverse habitat types. To investigate the causal mechanisms of the diversity at the eastern escarpment, we constructed landscape evolution models, tracing the dynamics of habitable land surface patches throughout model simulations.

The landscape of a great escarpment is dynamic and the heterogenous retreat of the escarpment and the water divide makes the geographically isolated drainage basins expand landward at different rates. Within the escarpment region, habitat patches dynamically appear, disappear, fragment, or merge at a frequency that scales with the retreat rate. The models predict that escarpment retreat fosters habitat patch dynamics such that patches isolate, or reconnect with a frequency on the order of a million years, appropriate for allopatric speciation. We conclude that the spatially heterogeneous but temporally steady retreat of the Madagascar escarpment since rifting has sustained allopatric speciation over evolutionary timescales resulting in the observed high diversity and its spatial pattern of eastern Madagascar.

River networks function as conduits for water and sediment transport across Earth's landscapes, while the elevated boundaries separating these networks, termed drainage divides, determine the partitioning of material fluxes among adjacent basins and establish physical barriers that restrict biotic dispersal. Variations in tectonics, climate, and lithology can alter the position of these divides, influencing water balance, erosion rates, sediment flux, and the geographic connectivity and evolutionary trajectories of biota. This study focuses on the overlooked temporal evolution of 'wind-gaps' (i.e. old river valleys transformed into in-valley drainage divides by drainage capture events) as an unstudied but key capture-related landform hypothesised to be fundamental in shaping post-capture-related landscape evolution. Using numerical landscape evolution modelling, our findings challenge the prevailing perception of wind-gaps as static landforms, revealing previously unrecognised mobility, with wind-gaps serving as mobile divides that reshape entire landscapes. Moving wind-gaps can trigger cascading morphological and erosional changes beyond an initial capture event, initiating a domino effect of captures of lateral tributaries to the pre-capture river. This can repeatedly alter the connectivity of riverine ecosystems, driving complex but predictable patterns of biotic diversification and leaving abiding imprints in the sedimentary and landscape records. Wind-gap propagation offers a mechanistic framework that opens avenues for deciphering complex linkages over time between landscape evolution, sediment dynamics, and biodiversity.

The application of the triple oxygen isotope system (¹⁶O-¹⁷O-¹⁸O) provides a new tool for stable isotope paleoaltimetry. Here, we use triple oxygen isotope (Δ’¹⁷O) geochemistry to determine the past elevation of the Eocene Kettle Metamorphic Core Complex (MCC) (Washington, USA). We analyze quartz-muscovite pairs from mylonitic quartzites from the MCC-bounding shear zone. δ¹⁸O values range from 4.8 to 11.3‰ (muscovite) and 6.8 to 14.6‰ (quartz) and Δ’¹⁷O values (λ_ref = 0.528) range from -0.054 to -0.077‰ (muscovite) and -0.052 to -0.071‰ (quartz). The calculated quartz-mica oxygen isotope equilibrium temperature averages 390°C ± 90°C, which in line with observed quartz microstructures. Compared to existing muscovite hydrogen isotope data (δD = -101 to -138‰), both approaches, δD-δ¹⁸O and δ’¹⁸O-Δ’¹⁷O, indicate oxygen and hydrogen isotopic exchange between syntectonically formed minerals and a meteoric-derived fluid within the Kettle shear zone. We find that the shear zone minerals are in isotopic equilibrium with a fluid having a δ¹⁸O_water value of ~-14‰, which likely reflects high-elevation inland precipitation. Combined with a low-elevation δ¹⁸O_water estimate (-6 to -8 ‰) from the Eocene near-coastal Chumstick Basin (WA, USA), the δ¹⁸O_water estimate translates into a paleoelevation of 3-4 km for the Eocene Kettle MCC. This is consistent with δD-based elevation estimates of 4.2 km and underscores the robustness and complementary nature of the two different isotopic approaches.

Chemical weathering in Southeast Asia is increasingly recognised as being a core control over global climate, particularly the cooling of Earth during the Cenozoic. This is particularly true during the Neogene when chemical weathering fluxes from the Himalayas decreased through time, meaning that silicate weathering in that region was not the primary control over falling CO₂ levels in the atmosphere. Instead, chemical weathering of sediments eroded from the arc and ophiolite terrains in Southeast Asia may be critical. Recent study of marine sedimentary deposits offshore Eastern New Guinea now show that there is a trend towards more intense chemical weathering in that region over the last 20 million years and especially since 6 Ma. Collision between New Guinea and Australia primarily commenced around 15 Ma when erosion from uplifting arc terrains made the sources especially reactive. Since that time uplift has created a large island with increasing erosion from continental Australian sources, reducing the reactivity. We estimate that sediments eroded from New Guinea maybe approximately 2 to 3 times as effective at consuming of CO₂ as their equivalents in South Asia. Over shorter, orbital timescales there is more erosion from accreted Australian crust during interglacial times when the stronger rainfall was able to penetrate deep into the New Guinea Highlands than during glacial times when erosion was more focused on mafic rocks along the coast. Chemical weathering intensity follows global climatic cycles with generally less weathering during interglacial warm periods, likely related to faster transport driven by high fluvial discharge.