1
$\begingroup$

252 million years ago, Siberia was subject to a mass series of flood basalt eruptions, creating a large igneous province called the Siberian Traps. Today, it measures three million square miles (7.77 km2) in area and a volume of one million cubic miles (4.17 km3). But that is the province's current size, which means that it has been measured with 252 million years of erosion into account.

So the question is—Do we have any idea how big the Siberian Traps were initially?

$\endgroup$
1

1 Answer 1

2
$\begingroup$

Short answer, there are various estimates, with large uncertainties, ranging from 4 to 7 million km2.

Pulling from the link provided by Keith McClary in the comments:

Estimating the original extent of the Traps is difficult, given the likely erosion over the last 250 Ma. This is especially important for the relatively easily eroded pyroclastic deposits. Whilst preservation may have been improved by burial in the West Siberian Basin and Yenesei-Khatanga Trough, it is unclear how much tectonic uplift and erosion occurred in these basins during the early Triassic, prior to burial. Milanovskiy (1976) estimated that the original extent of the Traps was about 4x106 km2, but there must be considerable latitude in this figure. Masaitis (1983), for example, has suggested that the Traps originally extended over a region of ~7 million km2.

Masaitis, V.L., 1983. Permian and Triassic volcanism of Siberia: Problems of dynamic reconstructions. Mineralogicheskogo Obshchestva, 112(4): 412-425.

Milanovskiy, Y.Y., 1976. Rift zones of the geologic past and their associated formations. International Geology Review, 18: 619-639.

Additionally I have found another estimate Saunders (2009):

The original total area (and volume) of the Siberian flood basalt province is difficult to estimate, because a substantial portion is covered by thick sedimentary se- quences and because an unknown amount has been re- moved by erosion. Taking the limits of the existing out- crops as a maximum extent, then we estimate that an area of approximately 5×106 km2 of Siberia may have been partly covered by basalt1. It is unlikely that an accurate figure of area (and volume) will ever be known.

Saunders, A., Reichow, M. The Siberian Traps and the End-Permian mass extinction: a critical review. Chin. Sci. Bull. 54, 20–37 (2009). https://doi.org/10.1007/s11434-008-0543-7

$\endgroup$
1
  • $\begingroup$ It is an absolutely mind boggling volume of magma, unprecedented in scale, outside of oceanic spreading centers. After some very expensive computer modelling, there was some discussion some years ago that an immense asteroid striking the opposite side of the globe might have focused energy into rupturing the crust in present day Siberia. What's known about the geophysical origins of these trapps? $\endgroup$ Jan 24, 2022 at 22:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.