Environmental Effects of Volcanic Volatile Fluxes From Subaerial Large Igneous Provinces

Abstract

Episodes of large igneous province (LIP) volcanism punctuate Earth history. LIPs are anomalous geologically rapid large-volume accumulations of igneous rock on the Earth's surface and in the shallow crust. Periods of LIP emplacement are often temporally associated with periods of profound environmental and climatic change in Earth history. The fluxes of gas and particles emitted during LIP volcanism are key candidates for triggering these Earth system responses. In this chapter, we review how and what we know about volcanic volatile fluxes from LIPs and their environmental effects. We discuss what gases are emitted from magmas and how attempts to quantify the emissions from LIPs are based on measurements of the LIP rocks themselves as well as petrological understanding gained by the study of more recent volcanic systems. There are also lessons to be learned from smaller-scale historical eruptions (that can serve as, albeit imperfect, analogues) and the opportunities that Earth system modeling studies offer. Future work should focus on reducing the uncertainties related to LIP volatile emissions budgets and constraining key LIP eruption parameters such as the intensity, tempo, and duration of not only eruptive episodes but also hiatus periods. The combination of better-defined input scenarios with further and more sophisticated Earth system modeling will play a key role in unlocking the mechanisms and scale of environmental impacts of LIP events.

Timescales of magma transport in the Columbia River flood basalts, determined by paleomagnetic data

“…They are more comparable to (although still larger than) previous estimates of individual CRB units, such as the Roza (∼0.58 km 3 /day; Thordarson and Self, 1998). Since the long-term CRB eruption rate is significantly less than the rates of individual eruptions determined in this study, this suggests activity from LIP-related basaltic volcanism is highly unsteady in time even during prolonged eruptive episodes (Mather and Schmidt, 2021). Although the CRB are smaller than other flood basalts, the volumes of CRB main phase eruptions ( 1000 km 3 ; ) are similar to the volumes of Deccan eruptions (Self et al, 2008).…”

Deoxygenation and organic carbon sequestration in the Tethyan realm associated with the middle Eocene climatic optimum

“…However, as Hg emitted per volume of volcanic gas is indistinguishable, this mainly results from the higher overall fluxes from studied arc volcanoes (Edwards et al, 2021). Long-term mean lava discharge rates over the approximately million-year lifetimes of some studied large igneous provinces are comparable to the longterm global mean arc magma discharge rate (Mather and Schmidt, 2021), suggesting that large igneous provinces likely represent a more significant perturbation to the Hg cycle than a single regional arc flare-up. Inferring eruption activity in volcanic arcs is further complicated by the observations from ice cores, which show far-field Hg spikes are not necessarily scaled to the volume of individual eruptions, likely as a result of heterogeneous dispersal and initial Hg loading (Schuster et al, 2002).…”

Recurring volcanic winters during the latest Cretaceous: Sulfur and fluorine budgets of Deccan Traps lavas

“…Reconstruction of magmatic fluxes for LIP events comes with large uncertainties, and quantifying the duration of time elapsed during magmatic hiatuses is one of the most challenging frontiers of LIP research ( 20 , 30 , 41 ). Short-term eruptive fluxes are generally much higher than fluxes calculated as averaged along the entire peak emplacement phase of a LIP (10 to 100 times higher in the case of the Deccan Traps) ( 20 ).…”

“…Volatile discharge and emplacement rates have been calculated for the Deccan Traps based on terrestrial mercury records and geochemical box models ( 25 – 27 ) but chemical data obtained directly from the volcanic material are still sparse. Available data on SO 2 and Cl ( 28 ) and CO 2 ( 23 , 29 ) from the Deccan Traps are mostly derived from melt inclusions found in rare occurrences (16 samples in total) of fresh olivine or plagioclase; estimates of fluorine concentrations have never been reported ( 20 , 30 ). Furthermore, previously published volatile estimates for the Deccan lavas come from flows that do not span the extinction interval ( 1 – 3 ), being restricted either to the oldest part of the WG [Kalsubai Subgroup ( 20 , 23 , 28 )] or to the youngest basalts [Wai Subgroup ( 29 , 31 )], which postdate the KPB.…”