67 Long- and Short-Term Environmental Consequences of Large Igneous Provinces Throughout Earth’s History (Posters)
We invite submissions to an interdisciplinary session on Large Igneous Provinces (LIPs), exploring their environmental impacts using geochronology, paleomagnetism, geochemistry, paleoenvironmental proxies, and modeling to integrate diverse data into understanding LIP-induced environmental changes.
Sunday, 19 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1
Quantitative Constraints on Large Igneous Province Gas Emissions: An Evaluation of Sedimentary Mercury Records
Paper number: 67-4
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM
Authors
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Oliver NeilsonPennsylvania State University, University Park, Pennsylvania
Abstract
Large Igneous Provinces (LIPs) affect the environment via the emission of climatically active gases, including carbon (CO2, CH4) and sulfur (SO2, SO4 aerosol). The flux and tempo of these gas emissions control the environmental response, with different feedback effects dominating depending on emission rates and duration. Hence, estimates of LIP gas emissions at high temporal resolution are critical to constrain the potential environmental impacts of a specific LIP. However, complex LIP chronostratigraphy and non-eruptive degassing make these estimates challenging.
Volcanism is the primary natural source of mercury to the environment. Thus, increases in mercury concentration in sedimentary archives have become established as a qualitative indicator of LIP activity. Recently, we have developed techniques moving towards quantitative reconstruction of volcanic gas fluxes using mercury records. However, a critical issue is that sometimes various mercury records show different patterns across the same time interval, making interpretation and inversion difficult.
Here, we use our understanding of the mercury cycle as represented by a modern environmental mercury box model (Amos et al., 2015) to evaluate two questions: A) What size/duration of eruptions are resolvable in sedimentary mercury records? Modern large, explosive eruptions are usually not observed in sedimentary records, but LIPs are – is this expected? B) How do mercury records vary between different environments (e.g., terrestrial, coastal marine, deep marine settings)? This is critical for disentangling volcanic signals from local environmental/depositional/diagenetic effects.
To answer these questions, we model mercury deposition in different environmental settings for a wide range of eruption (Hg emission event) rates and durations. Then, we statistically compare these results with published Hg records across the K-Pg and Toarcian-OAE, two events with globally distributed Hg records, testing whether the records are consistent with the same underlying forcing. We find that our model results, accounting for sediment accumulation rate and sampling resolution, effectively predict the pattern of enrichment between different environmental settings, supporting the use of mercury records as a quantitative proxy. The geologically short lifetime of mercury in the surface environment means that results are sensitive to some constraints, including sedimentary chronostratigraphy and non-LIP mercury cycle fluxes. We discuss the benefits and drawbacks of using gas fluxes from mercury records, in combination with carbon cycle models, as constraints on the environmental impacts of LIPs.
Geological Society of America Abstracts with Programs. Vol. 57, No. 6
doi: 10.1130/abs/2025AM-412778
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