The Jackson MS paleo-volcano is problematic but probably has been best explained by a process of snapback/tension relaxation related to the same process that formed the Sabine uplift of East Texas( 85mybp)--mainly through exclusion of other explanations, even it it was a 100million year loop from rift to eruption.
The Triassic Rift 190mybp left several smaller plates between the North and South America plates that had weighed down the new shelf margins. As the last tensions on the Gulf of Mexico's opening were unloaded, continental crust which had been thinnned and stretched snapped back (on geological time-scales where the crust had thinned during the failed rift related to the New Madrid (Failed Rift ) Seismic Zone and Missippi River Embayment. This could have been like squeezing a pimple where magma was slowly pooling but then squeezed to the surface.
Others include:
Chicxulub triggered but the Jackson Volcano was active 10-20my before that impact. Remember Chicxulub was a lot closer to Mississippi 65mybp but can't resolve the ages and an asteroid can't cause a volcano 20million years before it hits.
Passage over the Bermuda Hot Spot. From Kansas to Bermuda along the 38th parallel which, funny you should mention, is probably the cause for Hicks Dome. The Bermuda hotspot is an "intermittent" (for lack of a better word), eruptive hotspot which probably expended a lot of magma under the continental crust as the North American plate passed westward over it. I have seen formations called "pillow and column" which were attributed to strong seismic shaking. I was told that this was believed to be due to the passing of the Bermuda hotspot. A good theory is that in Permian, when Pangaea came together, the mantle was "overcrowed" with slabs being forced into it. On geological speeds the reaction was to squeeze up a plume. The area of the Bermuda plume was the weakest spot/link, so magma began seeping upwards only to meet thick continental crust --Otherwise we'd have more volcanoes in Tennessee. Incidentally, while the name escapes me, I believe there is a subducted slab of unknown origin ( Central California mini slab suture sequence?) which lies partially absorbed underneath the eastern US and may have something to do with the Yellowstone plume as well but the combined thickness of the mantle and crust is bulged under us. Couple that with the yet rebounding crust from the roots of the older Appalachains, the crust under the Eastern US is thicker than normal and the door of volcanic opportunity was and is closed for another100my.
The Triassic Rift 190mybp left several smaller plates between the North and South America plates that had weighed down the new shelf margins. As the last tensions on the Gulf of Mexico's opening were unloaded, continental crust which had been thinnned and stretched snapped back (on geological time-scales where the crust had thinned during the failed rift related to the New Madrid (Failed Rift ) Seismic Zone and Missippi River Embayment. This could have been like squeezing a pimple where magma was slowly pooling but then squeezed to the surface.
Others include:
Chicxulub triggered but the Jackson Volcano was active 10-20my before that impact. Remember Chicxulub was a lot closer to Mississippi 65mybp but can't resolve the ages and an asteroid can't cause a volcano 20million years before it hits.
Passage over the Bermuda Hot Spot. From Kansas to Bermuda along the 38th parallel which, funny you should mention, is probably the cause for Hicks Dome. The Bermuda hotspot is an "intermittent" (for lack of a better word), eruptive hotspot which probably expended a lot of magma under the continental crust as the North American plate passed westward over it. I have seen formations called "pillow and column" which were attributed to strong seismic shaking. I was told that this was believed to be due to the passing of the Bermuda hotspot. A good theory is that in Permian, when Pangaea came together, the mantle was "overcrowed" with slabs being forced into it. On geological speeds the reaction was to squeeze up a plume. The area of the Bermuda plume was the weakest spot/link, so magma began seeping upwards only to meet thick continental crust --Otherwise we'd have more volcanoes in Tennessee. Incidentally, while the name escapes me, I believe there is a subducted slab of unknown origin ( Central California mini slab suture sequence?) which lies partially absorbed underneath the eastern US and may have something to do with the Yellowstone plume as well but the combined thickness of the mantle and crust is bulged under us. Couple that with the yet rebounding crust from the roots of the older Appalachains, the crust under the Eastern US is thicker than normal and the door of volcanic opportunity was and is closed for another100my.
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