Understanding the spatial heterogeneity beneath Thwaites Glacier, West Antarctica, is vital to projecting its impact on future sea levels. Radar-echo sounding (RES) is commonly used to infer subglacial conditions, but these data can be challenging to interpret. We assess basal heterogeneity across Thwaites Glacier by comparing RES returns to a radar backscattering simulator for over 400 km of RES data. The modeled variations in bed returned power exhibited a strong correlation with actual RES data in $40\%$ of our simulated flight segments, which we consider evidence for a relatively homogeneous glacier bed. Other sites ($40\%$) demonstrated improved fit quality when hydrology or substrate transitions were introduced in the bed material model. The remaining simulated segments ($20\%$) were diagnosed as having more complex basal heterogeneity. The spatial distribution of complex heterogeneity appears to coincide with asymmetric patterns in the RES specularity content, which has been interpreted in previous studies as a signature for channelized hydrology. Conversely, the homogeneous substrate locations coincide with areas of fast-moving ice in western Thwaites. Our simulation method can isolate power variations induced by material heterogeneity vs topography, which is an important limitation of existing RES analysis methods.

This paper focuses on developing a robust control strategy for robotic manipulators, which are widely used in industrial and automation systems due to their flexibility and precision. However, their performance is often affected by factors such as unmodelled dynamics, friction and external perturbations, making accurate trajectory tracking a challenging task. To address these issues, an enhanced active disturbance rejection control (EADRC) scheme is proposed. The method employs an extended state observer (ESO) based on the system dynamics to estimate and compensate for internal uncertainties and external disturbances in real time. To boost the tracking accuracy, a nonlinear feedback control scheme is formulated. To further refine its performance, key controller parameters are tuned using an enhanced particle swarm optimisation (PSO) method, which incorporates elements of chaos theory to improve global search capability and convergence behaviour. The proposed EADRC method is evaluated through comparison with conventional controllers, and the results demonstrate its superior tracking accuracy and robustness.

The accurate identification of clay minerals and associated phases remains challenging, particularly in fine-grained samples with complex assemblages. To assist in their identification, this study introduces MinMatch, a database and automated search program containing over 500 oxide compositions of clay minerals and their associated phases from soils, sediments and rocks. The program compares normalized oxide data with reference entries and ranks potential matches using Pearson correlation coefficients, supported by SiO2:Al2O3 ratios and additional statistical and graphical parameters. Its performance is demonstrated using mineral oxide datasets from well-characterized samples of the 12th Reynolds Cup competition, derived from coarse- and fine-grained separates analysed using energy-dispersive X-ray spectroscopy combined with scanning and transmission electron microscopy. The results show that MinMatch consistently ranks compositionally equivalent minerals among the top matches and successfully discriminates between closely related varieties. The approach provides a rapid, quantitative and reproducible tool for clay mineral studies, complementing X-ray diffraction and other analytical methods.

The 14 elements from La to Lu (except the unstable Pm) form a group with similar chemical characteristics provided by their electronic configurations. Widespread, albeit in low abundance (hence their original description as ‘rare’), they were soon viewed as an opportunity to trace rock origins and geological processes. In addition to this scientific use, their technological applications have increased over the decades, which have multiplied in the present electronic age. Their exponential growth in demand and limited abundance have transformed them into strategic resources. Characteristic of clay minerals, which take centre stage in so many industrial applications and scientific issues, they have been discovered to be involved in this story as important commercial rare earth element (REE) deposits. This review describes how phyllosilicates bind REE, how environmental conditions modify REE contents in phyllosilicates and how such interactions can be used to trace both original rocks and the nature of modifying geological processes. Phyllosilicates bind REE strongly and concentrate them as adsorbed species in inner and outer poly-coordination complexes. This mode of binding controls the capacity for REE retention by phyllosilicates in conjunction with the physicochemical conditions of environmental fluids (salinity, pH, temperature, ligands, Eh) and fluid:rock ratios to determine the contribution of clay minerals to bulk REE signatures and their modifications in geological processes (soil formation, clay mineral precipitation from fluids, alteration, diagenesis, ore formation, transport).

Intra-terrane shear zones (ITSZs), though widespread across Proterozoic mobile belts, remain underexplored in their structural evolution and tectonic significance. This study explores the anatomy of the North Purulia Shear Zone (NPSZ), a ∼E–W trending, steeply dipping ITSZ within the Chotanagpur Granite Gneiss Complex (CGGC), eastern India. Integrated structural, kinematic, anisotropy of magnetic susceptibility (AMS) and microstructural analyses reveal that the NPSZ nucleated within megacrystic granite gneiss during late-Grenvillian tectonism (∼0.9–1.1 Ga), contemporaneous with Rodinia assembly. Field and AMS data demonstrate a sub-simple shear regime with a sinistral strike-slip component and magnetic fabrics transition from mixed oblate–prolate in host gneiss to only oblate in mylonitic zones. Recrystallized quartz grain aspect ratios increase significantly toward the core, coupled with elevated strain rates and decreasing flow stress. Deformation temperatures inferred from microstructural observation coupled with quartz dynamic recrystallization mechanisms suggest dominance of dislocation creep, which implies that the shearing took place at deep crustal level. The absence of precursor fractures or dykes and alignment of feldspar megacrysts suggest that the nucleation of the NPSZ was facilitated by anisotropy produced by the magmatic/sub-magmatic gneissic fabric, where interstitial smaller-sized quartz-rich domains in between K-feldspar megacrysts acted as viscous pathways. These findings not only provide first-order insights into ITSZ nucleation mechanisms but also reaffirm the CGGC as a site of late-Grenvillian crustal thickening related to the suturing of North and South Indian cratons during Rodinia amalgamation. The NPSZ thus emerges as a key intra-terrane tectonic structure recording Rodinia-linked crustal reworking within the Indian shield.

New-type metasedimentary rock-hosted stratiform Cu deposits occur in the Jianglang Dome. They are hosted by the Late Neoproterozoic Liwu Group and were unusually induced by an epigenetic magmatic-hydrothermal system. However, the source characteristics of fluids and metals remain poorly understood. Here, we employed Re-Os dating and He-Ar-S-Pb isotopes to determine their mineralization age and origin. Chalcopyrite Re-Os isotopic dating defines an isochron age of 162.7 ± 3.2 Ma and a crust-like initial 187Os/188Os ratio of 1.421 ± 0.021 (n = 4). Sulphide He-Ar isotope (n = 20) yields low R/Ra ratios of 0.052–0.144, high 40Ar/36Ar ratios of 479–2463 and low 40Ar*/4He ratios of 0.013–0.804, with calculated Hemantle values of 0.69–2.20 wt.%. In situ chalcopyrite sulphur isotope exhibits positive δ34SV-CDT values of 3.87–9.50‰ (n = 72). Together with similar lead isotope data of chalcopyrite separates (n = 40) and ca. 164 Ma granites (n = 4), as well as low residual gravity anomalies in this region, our integrated data indicate an epigenetic magmatic-hydrothermal mineralization at ca. 163 Ma. The ore-forming fluids were dominantly crust-derived, with minor air-saturated water and negligible mantle input (0.69–2.20 wt.%). This is most likely attributed to the low proportion (total <5 vol%) of sandwiched metabasic rocks in the metalliferous Liwu Group. All the investigated orebodies show source homogeneity, in contrast to classic sediment-hosted stratiform Cu deposits with isotopic heterogeneity. Further, our findings imply significant mineral exploration potential in the Jianglang Dome and analogous domes in the eastern Songpan-Ganze Orogen.

This article revisits the Finnish contribution to the First International Polar Year (IPY) (1882–1883) by examining a largely overlooked primary source: “On the Finnish Research Expedition to Sodankylä and Kultala in 1882–1884, with Sketches from Lapland” (Helsinki, 1885). Contrary to claims in recent scholarship that no detailed accounts of daily life at the Finnish polar station have survived, this volume offers rich descriptions of the expedition’s routines, challenges, and social interactions. Drawing on these narratives, the article reconstructs the everyday realities of scientific work in Sodankylä, including the arduous journey north, the setting up of observation facilities, the strict schedule of meteorological and magnetic observations, and the experimental studies on auroral phenomena led by Professor Selim Lemström. The analysis highlights why these accounts were forgotten – due to linguistic barriers and limited popular dissemination – and argues for their significance in understanding both the material culture of polar science and Finland’s role in the First IPY. By bringing this evidence into the historiography of Arctic research, the article challenges prevailing assumptions and calls for renewed attention to local perspectives in global scientific enterprises.