The abundances of 60 elements in 616 Ocean Floor Basaltic (OFB) glasses from the Abyssal Volcanic Glass Data File (AVGDF) Smithsonian Institution have been determined by laser‐ablation (LA)‐ICP‐MS and electron microprobe analysis (EMPA). analyzed include all 28 refractory lithophile elements, which provide framework for establishing geochemical behavior source volatile, chalcophile siderophile elements. In addition to traditionally (rare earth (REE), high field strength (HFSE), large ion...

The association of large Au–Cu–Ag ore deposits with convergent margins is commonly attributed to the higher content chalcophile elements in parental magmas generated at subduction zones compared mid-ocean ridges. We present new geochemical data for arc-like, relatively oxidized mantle-derived basalt rhyolite from Pual Ridge and vicinity, Eastern Manus Basin, which show that initial abundances base precious metals basalts are similar those ridge (MORB). contents Au, Cu, Ag built up evolving...

The Lau Backarc Basin (S.W. Pacific) hosts numerous spreading centers and rifts, including the Rochambeau Rifts (RR), Northwest Spreading Center (NWLSC), Central (CLSC). Samples from NWLSC, RR CLSC show no evidence for a subduction‐derived component in their mantle source regions or S loss during eruption. contents of glasses NWLSC many are lower than MORB at given FeO TOT , indicating melts were initially sulfide‐undersaturated. During differentiation, decrease Cu Ag ∼7 wt% MgO concomitant...

The Early Permian Variscan Cornubian Batholith is a peraluminous, composite pluton intruded into Devonian and Carboniferous metamorphosed sedimentary volcanic rocks. Within the batholith there are: G1 (two-mica), G2 (muscovite), G3 (biotite), G4 (tourmaline) G5 (topaz) granites. G1–G2 G3–G4 are derived from greywacke sources linked through fractionation of assemblages dominated by feldspars biotite, with minor mantle involvement in G3. formed though flux-induced biotite-dominate melting...

Abstract Metals such as Li, Be, V, Co, Nb, In, Cs, Sn, Ta, and W are considered resources that critical for modern economies. They can be significantly enriched in granites pegmatites, but the mechanisms of enrichment remain poorly understood. Many metal-enriched granitic magmas form through mica dehydration reactions during high-grade metamorphism. The preferential incorporation these metals into micas provides a mechanism concentration mobilization crustal melting. Comprehensive data sets...

Chemical analysis by laser‐ablation ICP‐MS can determine a large number of trace elements with precision approaching traditional whole‐rock analysis, but on scale that achieved the electron microprobe. These characteristics make it particularly attractive method for volcanic glasses, at present little is known about systematic errors, especially those from matrix effects. Here we investigate and accuracy LA‐ICP‐MS basaltic glasses 60 elements, including rare earth (REE), ion lithophile...

Abstract There is a lack of consensus regarding the roles sulfide saturation versus volatile degassing on partitioning Cu and Ag during differentiation eruption convergent margin magmas. Because their oxidized character, volatile‐rich magmas from Eastern Manus Back‐arc Basin (EMBB) only reach following magnetite‐driven reduction melt: so‐called “magnetite crisis.” If typically precedes saturation, magnetite crisis will limit proportion that can partition melt into an exsolving phase, which...

Abstract Mantle plume-related magmas typically have higher chalcophile and siderophile element (CSE) contents than mid-ocean ridge basalts (MORB). These differences are often attributed to sulfide-under-saturation of melts. However, because eruption-related degassing sulfur (S) the compositional, pressure, temperature redox effects on S-solubility, understanding magmatic behavior S is challenging. Using CSE data for oceanic plateau (OPB), which rarely degas S, we show that many OPB...

Abstract The 2018 lower East Rift Zone (LERZ) eruption and the accompanying collapse of summit caldera marked most destructive episode activity at Kı̄lauea Volcano in last 200 years. was extremely well‐monitored, with extensive real‐time lava sampling as well continuous geodetic data capturing collapse. This multiparameter set provides an exceptional opportunity to determine reservoir geometry magma transport paths supplying Kı̄lauea’s LERZ. forsterite contents olivine crystals, together...

Copper, obtained from porphyry deposits formed in arc settings, is a critical resource, and primarily sourced magmas. However, the processes that shape copper contents of magmas are up for debate. Existing models place emphasis on different petrological agents explain large-scale trends systematics. Previous studies have noted 'Cu paradox,' where with high Sr/Y ratios, indicative ore-forming potential, lowest concentrations. Here we compile multidimensional database volcanic whole rock...

The release of phosphorus (P) from crustal rocks during weathering plays a key role in determining the size Earth's biosphere, yet concentration P over time remains controversial. Here, we combine spatial, temporal, and chemical measurements preserved to reconstruct lithological evolution continental crust. We identify threefold increase average concentrations across Neoproterozoic-Phanerozoic boundary (600 400 million years), showing that preferential biomass burial on shelves acted...

Olivine-hosted melt inclusions are commonly used to determine pre-eruptive storage conditions. However, this approach relies on the assumption that co-erupted olivines have a simple association with their carrier melts. We show primitive olivine crystal cargoes and display high degree of geochemical disequilibrium melts at Kīlauea Volcano, Hawai'i. Within given eruption, trapped in crystals exhibit compositional diversity exceeding erupted lava compositions since 1790 CE. This demonstrates...

Abstract Magmas with matrix glass compositions ranging from basalt to dacite erupted a series of 24 fissures in the first 2 weeks 2018 Lower East Rift Zone (LERZ) eruption Kīlauea Volcano. Eruption styles ranged low spattering and fountaining strombolian activity. Major element trajectories glasses melt inclusions hosted by olivine, pyroxene plagioclase are consistent variable amounts fractional crystallization, incompatible elements (e.g., Cl, F, H O) becoming enriched 4–5 times as MgO...

The Fonualei Spreading Center affords an excellent opportunity to evaluate geochemical changes with increasing depth the slab in Lau back‐arc basin. We present H 2 O and CO concentrations Sr, Nd, Pb, Hf U‐Th‐Ra isotope data for selected glasses as well new from boninites seamounts north of Tonga arc. Pb are used show that mantle flow is oriented southwest tear northern end may not extend east far boninite locality. Along Center, key parameters change smoothly distance arc front surface...

Geophysical observations suggest sub-arc convective flow transports melt-exhausted and metasomatized wedge mantle into deeper regions.Reciprocally, asthenospheric, fertile may supply back-arc ridges distal to the trench by shallow, lateral ingress, insinuating initial depletion in its region.Here we show that light Fe isotope compositions of Central Lau Spreading Centre located basin on farside Tonga-Kermadec arc are indicative for derivation from a modified arc-front with elemental...

The 3 km long Bellevue Core was recovered from the Upper Zone (UZ) and Main (MZ) of Northern Limb Bushveld Complex—the largest known layered mafic intrusion. We present abundance data for 57 trace elements hosted in plagioclase, clinopyroxene, low-Ca pyroxene olivine, obtained by laser ablation inductively coupled plasma mass spectrometry. These permit first comprehensive investigation element distribution Complex on a mineral-by-mineral basis, show that Cr content is only proxy records...