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Large Igneous Province eruptions coincide with many major Phanerozoic mass extinctions, suggesting a cause-effect relationship where volcanic degassing triggers global climatic changes. In order to fully understand this relationship, it is necessary to constrain the quantity and type of degassed magmatic volatiles, and to determine the depth of their source and the timing of eruption. Here we present direct evidence of abundant CO 2 in basaltic rocks from the end-Triassic Central Atlantic Magmatic Province (CAMP), through investigation of gas exsolution bubbles preserved by melt inclusions. Our results indicate abundance of CO 2 and a mantle and/or lower-middle crustal origin for at least part of the degassed carbon. The presence of deep carbon is a key control on the emplacement mode of CAMP magmas, favouring rapid eruption pulses (a few centuries each). Our estimates suggest that the amount of CO 2 that each CAMP magmatic pulse injected into the end-Triassic atmosphere is comparable to the amount of anthropogenic emissions projected for the 21 st century. Such large volumes of volcanic CO 2 likely contributed to end-Triassic global warming and ocean acidification.

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Peridotite xenoliths from the Nó grá d-Gö mö r Volcanic Field (NGVF) record the geochemical evolution of the subcontinental lithospheric mantle beneath the northern margin of the Pannonian Basin. This study is focused on spinel lherzolites and presents petrography, and major and trace element geochemistry for 51 xenoliths selected from all xenolith-bearing localities of the NGVF. The xenoliths consist of olivine, orthopyroxene, clinopyroxene and spinel 6 amphibole. No correlations between modal composition and textures were recognized; however, major and trace element geochemistry reveals several processes, which allow the distinction of xenolith groups with different geochemical evolution. The xenoliths have undergone varying degrees ($7-25%) of partial melting with overprinting by different metasomatic processes. Based on their Mg#, the xenoliths can be subdivided into two major groups. Group I has olivine Mg# between 89 and 91, whereas Group II has Mg# <89, significant enrichment of Fe and Mn in olivine and pyroxenes, and high Ti in spinel. Trace element contents of the xenoliths vary widely, allowing a further division based on light rare earth element (LREE) enrichment or depletion in pyroxenes. REE patterns of amphiboles match those of clinopyroxenes in each xenolith where they appear, and are inferred to have different origins based on their Nb (and other high field strength element) contents. It is proposed that Nb-poor amphiboles record the oldest metasomatic event, caused by subduction-related volatilebearing silicate melts or fluids, followed by at least two further metasomatic processes: one that resulted in U-Th-(Nb-Ta)-LREE enrichment and crystallization of Nb-rich amphibole, affecting

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