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The paucity of rocks from Earth’s first billion years (4.5–3.5 Ga) limits understanding of early felsic (continental) crust formation and craton development. We present zircon U–Pb, O- and Hf-isotope and whole-rock geochemical data from deformed and metamorphosed (ultra)mafic and felsic rocks of the Archaean Lewisian Gneiss Complex, NW Scotland. The felsic, MgO-rich hornblende-bearing tonalite gneisses contain magmatic zircon populations at c. 3.6, 3.5, and 2.8 Ga, as do enclosed hornblendite pods (>95 vol.% hornblende). Zircons from hbl-tonalite preserve median δ¹ 8 O (zircon) of ~5.8‰, indicating limited supracrustal input. The hornblendites have high-MgO (~18 wt%), Cr (up to 5500 µg/g), and Ni (up to 2800 µg/g) concentrations and record slightly higher δ¹ 8 O (zircon) median values (~6.3‰). Zircon εHf (zircon) from both lithologies implies a Hadean to early Archaean (c. 4.1–3.9 Ga) depleted mantle source variably modified by low-temperature surface-derived fluids and/or incorporation of Hadean continental crust. We argue that the hornblendites represent vestiges of a hydrated (proto)crust that contributed to the growth of the earliest Archaean continental nuclei. Ancient rocks from northwest Scotland show that early continental crust formed in water-rich environments. The data suggest that primordial water was already present in the lower crust and was recycled from altered surface rocks into deeper crustal levels.

This article presents a resource for automated search, extraction and collation of geochemical and geochronological data from the Figshare repository using web scraping code. To answer fundamental questions about the Earth’s evolution, such as spatial and temporal evolution and interrelationships between the planet’s solid and surficial reservoirs, researchers must utilize global geochemical datasets. Due to the volume of data being published, these datasets become quickly outdated. We present a resource that allows researchers to rapidly curate and update their own databases from existing published data. We use open-source Python code to web scrape the Figshare repository for journal supplementary files using the application programming interface, allowing for the collection and download of hundreds of supplementary files and metadata in minutes. Use of this web scraping tool is demonstrated here by collation of a zircon geochronology and chemistry database of >150,000 analyses. The database is consistent in reproducing trends in other published zircon compilations. Providing a resource for automated collection of Figshare data files will encourage data sharing and reuse. Measurement(s) age and chemistry of zircon Technology Type(s) mass spectrometry

The Nimbus Ag–Zn(–Au) deposit is a hybrid VHMS deposit with epithermal characteristics formed in the Eastern Goldfields Superterrane, Yilgarn Craton, under shallow water (~ 700 mbsl), low-temperature conditions. Intersections of some ore lenses are high-grade and polymetallic, making similar styles of mineralization attractive Yilgarn exploration targets. The mineralization at Nimbus is hosted by a bimodal felsic–mafic succession of volcanic rocks, which are overlain by a succession of least-altered polymict conglomerates with a carbonaceous to dacitic matrix. A new Re–Os age (2680 ± 34 Ma; nodular pyrite and black shale) suggests that the overlying polymict conglomerate is coeval to ~ 2.70 Ga volcanism and mineralization at Nimbus. The pyrite within the high-grade polymetallic sulfide assemblages has a consistently lower Sb/Ag ratio (1–30) than pyrite from other sulfide phases (e.g., 30 to 1000 in colloform and barren pyrite). Trace elements (TEs) in sedimentary nodular pyrite from multiple intervals along a single drillhole (NBDH010), indicate the existence of an enriched sedimentary interval with higher total TE content, Ag/Au and Sb/Au, lower S/Se, and polymetallic-like signature of Sb/Ag. Within this enriched interval, the black shale matrix of the polymict conglomerate shows higher total organic carbon (TOC), Mo content, and Co/Ni ratios and suggest increased bio-activity at that time, interpreted to be associated with the Ag–Zn(–Au) mineralization. The TE characteristics in sedimentary pyrite, reflecting increased metal content in seawater inferred from in situ pyrite trace element analysis has the potential to be developed into an exploration tool for successions, adjacent and coeval to similar ore deposits.

With new advances in rapid-acquisition geochemical and hyperspectral techniques, exploration companies are now able to detect subtle halos surrounding orebodies at minimal expense. The Nimbus Ag-Zn-(Au) deposit is unique in the Archean Yilgarn Craton of Western Australia. Due to its mineralogy, alteration assemblages, geochemical affinity, and tectonic setting, it is interpreted to represent a shallow water (~650 mbsl) and low-temperature (<250 °C) volcanogenic massive sulfide (VMS) deposit with epithermal characteristics (i.e., a hybrid bimodal felsic deposit). We present a detailed paragenetic account of the Nimbus deposit, and establish lithogeochemical and hyperspectral halos to mineralization to aid exploration. Mineralization at Nimbus is characterized by early units of barren massive pyrite that replace glassy dacitic lavas, and underlying zones of polymetallic sulfides that replace autoclastic monomict dacite breccias. The latter are dominated by pyrite-sphalerite-galena, a diverse suite of Ag-Sb ± Pb ± As ± (Cu)-bearing sulfosalts, minor pyrrhotite, arsenopyrite, and rare chalcopyrite. The main sulfosalt suite is characterized by pyrargyrite, and Ag-rich varieties of boulangerite, tetrahedrite, and bournonite. Zones of sulfide mineralization in quartz-sericite(±carbonate)-altered dacite are marked by significant mass gains in Fe, S, Zn, Pb, Sb, Ag, As, Cd, Ni, Cu, Ba, Co, Cr, Tl, Bi, and Au. Basaltic rocks show reduced mass gains in most elements, with zones of intense quartz-chlorite-carbonate±fuchsite alteration restricted to thick sequences of hyaloclastite, and near contacts with dacitic rocks. Broad zones of intense silica-sericite alteration surround mineralization in dacite, and are marked by high Alteration Index and Chlorite-Carbonate-Pyrite Index (CCPI) values, strong Na-Ca depletion, and an absence of feldspar (albite) in thermal infrared (TIR) data. White mica compositions are predominantly muscovitic in weakly altered sections of the dacitic footwall sequence. More paragonitic compositions are associated with zones of increased sericitization and high-grade polymetallic sulfide mineralization. Chlorite in dacitic rocks often occurs adjacent to zones of sulfide mineralization and is restricted to narrow intervals. Carbonate abundance is sporadic in dacite, but is most abundant outside the main zones of Na-Ca depletion. Basaltic rocks are characterized by strongly paragonitic white mica compositions, and abundant chlorite and carbonate. Shifts from Ca carbonates and Fe-rich chlorites to more Mg-rich compositions of both minerals occur in more intensely hydrothermally altered basaltic hyaloclastite, and near contacts with dacitic rocks. Hanging-wall polymict conglomerates are characterized by minor amounts of muscovitic to phengitic white mica (2205–2220 nm), and an absence of chlorite and carbonate alteration.