This dataset encompasses thin section photographs, mineral composition data and Ar/Ar data. Grant abstract: Many of the Earth's great mountain ranges, such as the Alps and the Himalaya, result from the collision between two continents. As mountains get pushed up by tectonic forces, they also get worn away by surface erosion. The uplift of topography causes long-term regional and global climate change, and conversely, changes in climate have also been linked to changes in the rate of tectonic processes. This project will define and quantify the competition between growth and erosion during the early stages of mountain uplift by exploiting a combination of state-of the art advances in numerical modelling and analytical techniques. During the early stages of continental collision, unusual (and diagnostic) rock types form under very high pressure conditions. Certain minerals in these rocks preserve details of the pressures and temperatures experienced during the journey from initial formation deep in the mantle, through their subsequent transport to the Earth's surface, their erosion, and their final deposition as sand grains in a sedimentary rock. The minerals retain distinctive chemical signatures which allows them to be distinguished from those formed in other rock types, even when eroded and turned into sand. Sand grains retain information about not only the original rock type, but also about details of the formation and transport history of the original rock. Unlocking this information will therefore yield insight into earlier stages of mountain belt growth history than is currently preserved in the bedrock record. However the methods needed to decipher these details are currently insufficiently precise to provide useful insight into changes in rates of tectonic or erosive processes, or constraints for the models. This project will therefore also develop and exploit innovative techniques for obtaining high-precision data from these high pressure rocks and their eroded remains. These data will enable the competing forces which act to shape a mountain belt during the early stages of formation to be quantified and allow the numerical models to be robustly tested. The unique contribution of this proposal lies in the combination of geodynamic numerical modelling with studies based on observational data and hence exploiting the synergy between these two, normally disparate, fields.

Whole rock Hafnium (Hf) isotope data for mid-oceanic ridge basalt (MORB) samples from the Reykjanes ridge, Arctic Ocean, Equatorial MAR, South MAR, SEIR. The Hf isotope results are not yet published but will contribute to the mantle characterisation efforts detailed in Béguelin et al. (2025) (https://doi.org/10.1029/2025GC012357). Mid-Ocean Ridge Basalt (MORB) glasses were crushed and sieved to ~600 µm. Chips were then hand-piked under a binocular microscope to remove alteration (only optically clear chips selected). Hf fractions were purified using the column chemistry protocol of Béguelin et al. (2017) and references therein (https://doi.org/10.1016/j.gca.2017.09.015). Hf isotope ratios were measured on a Nu Instruments Plasma II mass spectrometer equipped with an Aridus desolvating nebuliser, on 50 ppb solutions. Accuracy and precision were monitored with repeated measurements of the JMC-475 standard (reported in dataset). Scanning Electron Microscopy-Energy Dispersive Spectrometry (SEM EDS) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) major and trace elements maps of eclogites from the Raspas complex (Ecuador). Samples were prepared as 1-inch epoxy mounts. Samples are described in John et al. (2010) (https://doi.org/10.1007/s00410-009-0427-0). The objective of this (present) work is to trace U, Pb and Th fluxes during subduction, as documented by obducted eclogites. Dataset includes SEM mapping of major elements with a Zeiss Sigma HD Field Emission Gun Analytical Scanning Electron Microscope (SEM) using energy dispersive X-ray spectroscopy (EDS). Elements measured are Fe, Ca, Cu, Ni, Mn, K, Na, Al, Mg, Ti, O, Cr, S, Si, P, Zr. Resolution is 25µm. Dataset also includes LA-ICP-MS mapping of trace elements using an Elemental Scientific ESL213 laser coupled to a Thermo Scientific iCap Q mass spectrometer. Elements measured are Rb, Sr, Mo, Cs, La, Yb, Pb, Th, U. Parameters: Raster spacing (resolution): 40µm, scan speed: 80 µm/s, rep rate: 20 Hz, fluence: 4.5 J/cm2, dwell time per element: 50 ms, injector: ESI dual concentric injector (DCI). SEM data are in weight %, LA-ICP-MS data are in µg/g (ppm). Data are unpublished, but further details can be found in the poster included with the dataset. Dataset was produced at the School of Earth and Environmental Sciences, Cardiff University, in the context of NERC grant NE/T012633/1 Mantle Circulation Constrained (MC2): A multidisciplinary 4D Earth framework for understanding mantle upwellings.