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Titanium stable isotope and major and trace element compositions of Archean and Paleoproterozoic sanukitoids and Paleozoic high Ba-Sr granite suites

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Operational Dataset about drilling in the Moodies Group of the Barberton Greenstone Belt (BASE – Barberton Archean Surface Environments)

All datasets provided in the operational dataset (Heubeck et al., 2024) of the ICDP project BASE (ICDP 5069) consist of metadata, data and/or images. Here, a summary of explanations of the tables, data and images exported from the database of the project (mDIS BASE) are given and are complemented by additional information on data from measurements done in the laboratory prior to the sampling party. Finally, the sampling data from the first two sampling parties are added. Some basic definitions of identifiers used in ICDP, depths corrections and measurements are also introduced. The BASE (Barberton Archean Surface Environments) scientific drilling project focused on recovering unweathered continuous core through strata of the Paleoarchean Moodies Group (ca. 3.2 Ga), central Barberton Greenstone Belt (BGB), South Africa. They comprise some of the oldest well-preserved sedimentary strata on Earth, deposited within only a few million years in alluvial, fluvial, coastal-deltaic, tidal, and prodeltaic settings; they represent a very-high-resolution record of Paleoarchean surface conditions and processes. Moodies Group strata consist of polymict conglomerates, widespread quartzose, lithic and arkosic sandstones, siltstones, shales, and rare BIFs and jaspilites, interbedded with tuffs and several thin lavas. This report describes operations from preparations to the sampling workshop and complements the related scientific report. Eight inclined boreholes between 280 and 495 m length, drilled during November 2021 through July 2022, obtained a total of 2903 m of curated core of variable quality through steeply to subvertically dipping, in part overturned stratigraphic sections. All drilling objectives were reached. Boreholes encountered a variety of conglomerates, diverse and abundant, mostly tuffaceous sandstones, rhythmically laminated shale-siltstone and banded-iron formations, and several horizons of early-diagenetic sulfate concretions. Oxidative weathering reached far deeper than expected; fracturing was more intense, and BIFs and jaspilites were thicker than anticipated. Two km-long mine adits and a water tunnel, traversing four thick stratigraphic sections within the upper Moodies Group in the central BGB, were also sampled. All boreholes were logged by geophysical instruments. Core was processed (oriented, slabbed, photographed, described, and archived) in a large, publicly accessible hall in downtown Barberton. An exhibition provided background explanations for visitors and related the drilling objectives to the recently established Barberton-Makhonjwa Mountains World Heritage Site. A substantial education, outreach and publicity program addressed the information needs of the local population and of local and regional stakeholders.

2D grain size data of sandstones from the 3.2 Ga old Moodies Group, Barberton Greenstone Belt (South Africa)

The Moodies Group (ca. 3.22-3.21 Ga) of the Barberton Greenstone Belt (BGB), South Africa, is the uppermost and youngest unit of the BGB, the largest and best-preserved Greenstone belt in the basement of the Kaapvaal Craton. It consists predominantly of fine- to coarse-grained, composi-tionally immature to mature, quartzose sandstones up to 3.6 km thick, with significant units of con-glomerates and siltstones and minor volcanic rocks and ferruginous sediments. The quartz-dominated Moodies sandstones mark long-term, large-scale access of surface systems to crust-stabilizing, high-level granitoid igneous rocks. 47 petrographic thin sections of sandstones from these sandstone units were analyzed for 2D grain size analyses. At least 500 measurements of long axes per thin were taken, using a Keyence VHX-6000 digital microscope. Samples which show significant grain boundary migration and subgrain rotation were excluded from this analysis (Passchier and Trouw, 2005). The data are presented as single ASCII file (tab-delimited text). The file 2022-023_Reimann-et-al_2D-grain-size-data.txt contains measurements of grains long axes from thin sections.

Compilation of global Archean and Paleoproterozoic sanukitoid geochemical data

Sanukitoids, also referred to as high-Mg diorites, are a distinctive type of igneous rock from the late Archean-early Proterozoic, and are characterised by enrichment in both compatible elements (e.g. Mg, Ni, Cr) and incompatible elements (e.g. Ba, Sr, light rare earth elements). Their geochemistry is typically interpreted as recording petrogenesis of their parental magmas via interaction between mantle peridotite and recycled crust-derived component (e.g. metabasite melts, sediment melts, aqueous fluids), and is often considered to be "transitional" between that of Archean sodic tonalite-trondhjemite-granodiorite (TTG) suites and post-Archean potassic granites. This dataset presents a global compilation of all Archean-Paleoproterozoic rocks that have been described as "sanukitoid" in published literature, and consists of over 3600 individual samples. Whole rock major and trace element concentrations, radiogenic isotope compositions and stable isotope compositions are compiled in the dataset alongside reported magmatic ages of the samples. The dataset is provided both as an Excel workbook divided by craton (file: 2025-003_Spencer-et-al_Sanukitoid-Compilation.xlsx) and as a single CSV file (file: 2025-003_Spencer-et-al_Sanukitoid-Compilation.csv). Sanukitoid magmatism has been described on almost every Archean craton globally. Most reported sanukitoid magmatism occurred during the late Mesoarchean-Neoarchean (2.95 - 2.5 Ga), with another peak in sanukitoid magmatism in the mid-Paleoproterozoic (2.2 - 2.0 Ga). Older sanukitoid occurrences dating back to the Paleoarchean (>3.2 Ga) are also described in the literature.

Compilation of global Archean high-Sr tonalite-trondhjemite-granodiorite (TTG) geochemical data

Tonalite-trondhjemite-granodiorite (TTG) suites are the main constituent of Archean (4-2.5 Ga) continental crust. High-Sr TTGs are a subgroup of "high-pressure" TTGs characterised by very high Sr concentrations (>500 ppm, but often >700 ppm) and Sr/Y (>100), in addition to K2O/N2O<0.5, Yb<0.4 ppm and La/Yb>60 at SiO2≈70 wt%. High-Sr TTGs may have formed via fractional crystallisation of metasomatised mantle-derived sanukitoid magmas, in contrast to the dominant petrogenetic model for "high-pressure" TTGs involving metabasite partial melting at pressures >2 GPa. This dataset presents a compilation of global high-Sr TTG occurrences identified from published literature, and contains their compiled major and trace element and Nd isotope compositions.

Titanium stable isotope compositions of Neoarchean tonalite-trondhjemite-granodiorite (TTG) suites from the Eastern Goldfields Superterrane, Yilgarn Craton

We report the titanium (Ti) stable isotope compositions (δ49Ti) of Neoarchean (ca. 2700-2650 Ma) tonalite-trondhjemite-granodiorite (TTG) suites from the Eastern Goldfields Superterrane, Yilgarn Craton. Samples were selected to cover the full range of trace element compositions exhibited by TTGs, and are primarily from the Kalgoorlie-Kambalda region of the Kalgoorlie Terrane. Ti stable isotope compositions were measured using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) at the Cardiff Earth Laboratory for Trace Element and Isotope Chemistry (CELTIC), Cardiff University. The Ti isotope compositions of these samples (file: 2025-009_Spencer-et-al_Ti-Isotope-Data.xlsx) are presented alongside a compilation of their major and trace element concentrations (file: 2025-009_Spencer-et-al_Compiled-Isotope-Major-Trace-Element-Data.xlsx) taken from the Western Australian Geochemistry Database (WACHEM). Most TTG samples have δ49Ti values between 0.2 to 0.6‰ that increase with SiO2 content, while two highly evolved TTGs have δ49Ti > 1‰. At SiO2 ≈ 70 wt% the different TTG geochemical groups display distinct Ti isotope compositions.