Abstract. Recent attempts to establish the eruptive history of the Deccan Traps large igneous province have used both U−Pb (Schoene et al., 2019) and
40Ar/39Ar (Sprain et al., 2019) geochronology. Both of these studies report dates with high precision and unprecedented coverage
for a large igneous province and agree that the main phase of eruptions began near the C30n–C29r magnetic reversal and waned shortly after the
C29r–C29n reversal, totaling ∼ 700–800 kyr duration. These datasets can be analyzed in finer detail to determine eruption rates, which
are critical for connecting volcanism, associated volatile emissions, and any potential effects on the Earth's climate before and after the
Cretaceous–Paleogene boundary (KPB). It is our observation that the community has frequently misinterpreted how the eruption rates derived from
these two datasets vary across the KPB. The U−Pb dataset of Schoene et al. (2019) was interpreted by those authors to indicate four major
eruptive pulses before and after the KPB. The 40Ar/39Ar dataset did not identify such pulses and has been largely interpreted by
the community to indicate an increase in eruption rates coincident with the Chicxulub impact (Renne et al., 2015; Richards et al., 2015). Although
the overall agreement in eruption duration is an achievement for geochronology, it is important to clarify the limitations in comparing the two
datasets and to highlight paths toward achieving higher-resolution eruption models for the Deccan Traps and for other large igneous provinces. Here,
we generate chronostratigraphic models for both datasets using the same statistical techniques and show that the two datasets agree very well. More
specifically, we infer that (1) age modeling of the 40Ar/39Ar dataset results in constant eruption rates with relatively large
uncertainties through the duration of the Deccan Traps eruptions and provides no support for (or evidence against) the pulses identified by the
U−Pb data, (2) the stratigraphic positions of the Chicxulub impact using the 40Ar/39Ar and U−Pb datasets do not
agree within their uncertainties, and (3) neither dataset supports the notion of an increase in eruption rate as a result of the Chicxulub
impact. We then discuss the importance of systematic uncertainties between the dating methods that challenge direct comparisons between them, and we
highlight the geologic uncertainties, such as regional stratigraphic correlations, that need to be tested to ensure the accuracy of eruption
models. While the production of precise and accurate geochronologic data is of course essential to studies of Earth history, our analysis
underscores that the accuracy of a final result is also critically dependent on how such data are interpreted and presented to the broader community
of geoscientists.
An evaluation of Deccan Traps eruption rates using
geochronologic data
