As I understand it, some of the current thinking is that the Columbia basalts were a product of the Farallon plate slab remnant impeding rising magma from the YHS plume -- magmas which eventually broke through, millions of years after the Tillamook volcanics induced by the NA plate initially overriding the YHS.
Very interesting work here, can’t wait to read the papers. If you just do a simple back of the envelope calculation on the Grande Ronde basalt given the parameters of total volume (~149,000 km3) and duration (400ka), you get a constant eruptive rate of 11.8 m3/s, which is basically equivalent to the Fagradalsfjall eruption’s average eruptive rate…but constant for every second for 400,000 years…which is insane. And needless to say, it wasn’t constantly erupting for 400,000 years, but that just gives you an idea of the massive quantity of lava involved. In terms of more realistic eruptive scales, if you consider there are around 100 members in the Grande Ronde Formation, imagine that each one of those was a single massive eruption (I know, very oversimplified…again, back of the envelope here) and just pick a 4.5 years as the eruptive duration of each of those members, based on the content of this talk, with the results of the Bayesian model of 3-6 years (not all dikes are this large, but again…), you would get something like 10,490 cubic m/s constant eruptive rate, 100 times for 4.5 years constant, within a 400ka timespan. When you consider Laki had an average eruptive rate of 2,300 cubic m/s, with estimates of maximum eruptive rate as high as 8,500 cubic m/s, though, this doesn’t seem too far fetched, maybe even a little low considering the ~10x Laki slide shown at the end of this presentation. Completely unimaginable amounts of lava. What I am really interested in seeing is how lava flow behavior changes when the rate is so high like this. Clearly, spectacular things are capable of occurring, like sheetflows traversing an entire state, burying themselves in fresh sediments offshore, and re-erupting through a rootless submarine vent.
As I understand it, some of the current thinking is that the Columbia basalts were a product of the Farallon plate slab remnant impeding rising magma from the YHS plume -- magmas which eventually broke through, millions of years after the Tillamook volcanics induced by the NA plate initially overriding the YHS.
Very interesting work here, can’t wait to read the papers. If you just do a simple back of the envelope calculation on the Grande Ronde basalt given the parameters of total volume (~149,000 km3) and duration (400ka), you get a constant eruptive rate of 11.8 m3/s, which is basically equivalent to the Fagradalsfjall eruption’s average eruptive rate…but constant for every second for 400,000 years…which is insane. And needless to say, it wasn’t constantly erupting for 400,000 years, but that just gives you an idea of the massive quantity of lava involved. In terms of more realistic eruptive scales, if you consider there are around 100 members in the Grande Ronde Formation, imagine that each one of those was a single massive eruption (I know, very oversimplified…again, back of the envelope here) and just pick a 4.5 years as the eruptive duration of each of those members, based on the content of this talk, with the results of the Bayesian model of 3-6 years (not all dikes are this large, but again…), you would get something like 10,490 cubic m/s constant eruptive rate, 100 times for 4.5 years constant, within a 400ka timespan. When you consider Laki had an average eruptive rate of 2,300 cubic m/s, with estimates of maximum eruptive rate as high as 8,500 cubic m/s, though, this doesn’t seem too far fetched, maybe even a little low considering the ~10x Laki slide shown at the end of this presentation. Completely unimaginable amounts of lava. What I am really interested in seeing is how lava flow behavior changes when the rate is so high like this. Clearly, spectacular things are capable of occurring, like sheetflows traversing an entire state, burying themselves in fresh sediments offshore, and re-erupting through a rootless submarine vent.
Fascinating work. As a dabbler, I comprehend only dimly, but it is intriguing nonetheless.