While reporting on many interesting known facts concerning geology of the eruptions, some remarks in the program appeared to be in error: Although the idea of a hotspot track was mentioned, with the Hawaiian sea mount chain given as an example, the astounding declaration was made that the Siberian eruptions ended after a million years (~249 M yrs ago) and no hotspot track for the Siberian hotspot was known, so stated explicitly.
To the contrary, I believe the hotspot track is clearly visible on Google maps satellite image (NOT Google Earth, which is a bit blurry), see below for details, eruptions continuing ever since.
The track’s total extent includes a continental and an oceanic part. It stretches from the Siberian Basin to the Hawaiian volcanoes, so that in fact the hotspot related to the end-Permian extinction event is known, eruptions have gone on at first in the form of super-volcanoes, at least until early Cretaceous times, finally subsiding gradually to today’s Hawaiian volcanoes, as explained further below.
In Siberia proper, the hotspot track passes just N of Yakutsk and runs from NW to SE across the map, as an almost exactly straight line (testimony to the exceedingly steady plate motion over 150 M yrs of the Earth’s crust as it dragged across the hotspot in the mantle beneath).The track should stand out clearly and be visible by its discoloration on the satellite image, sometimes brighter, or darker, than the surround.Its visible aspect terminates in a promontory East of Magadan on the Sea of Okhotsk. The NW terminus is at the Putorana Plateau, recognizable by its deeply dissected surface, with the city of Noril’sk on its Western edge. The Siberian Basin is adjacent to the West.
From East of Magadan the track runs under the Sea of Okhotsk (buried beneath sediment) and under Kamchatka, to emerge in the Great Cusp formed by the Kuril and Aleut island chains and by the corresponding plate tectonic subduction trenches, an event reliably dated to a little over 85 M yrs ago, the age of the Detroit Seamount, Western-most for which DSDP cores could be dated. The cusp formed by the trenches, by all appearances, is due to the hotspot track which is anchored deep in the mantle resisting subduction. The track goes on in the Emperor-Hawaii sea mount chain.
[Brief detailed map instructions: To see the track on your browser, open maps.google.com and enter “Yakutsk” then click “search maps”. Choose satellite view (upper right of screen). Click the arrows (<<, upper left), to open map to full width. Move zoom slide down until the scale on the lower left hand corner says 200 km. The map will show maybe 3,000 km of Siberian territory from West to East. Drag the map slightly so that the Magadan promontory with the SE terminus of the visible part of the track is in the lower right hand corner of your screen. At the 200 km scale, the Putorana Plateau should be on the upper left corner, if not try clicking <<, or it may be necessary for you to use screen zoom features.]
Controversially, the Siberian Basin and S Kara Sea to the West are the origin of the hotspot where a giant comet hit that ended the Permian period (>100 km diameter, perhaps a Kuiper Belt object), breaking into two or more fragments due to “impact focussing”, i.e., near Earth tidal forces tearing apart the lumpy, dirty snowball that a comet is, loosely held together by internal gravity. The double S-curve of the Urals forms a partial crater wall for the two adjacent 2,000 km diameter impact craters.The cross section of the mountain chain and numerous geological details are evidence for this fact. The city of Perm is on the gentle West slope.(Where is the rest of the crater wall, .. perhaps in N America?)
The former Mongol-Okhotsk Ocean was reduced to the current Sea of Okhotsk in late Jurassic/ early Cretacious times when the growing hotspot track caused fusion of mainland Asia and Siberia.
The famous dinosaur beds in the Gobi desert and Liaoning province were laid down at that time, fine ash from super-volcano (caldera) eruptions of the hotspot burying and preserving amazing detail of feathered dinosaurs and early birds, when the caldera was near Yakutsk. In that period, the region was in a subtropical location, as the hotspot has moved little over time if at all. The giant impact likely caused the vast Pacific Ocean to open with Hawaii still near its center even today, splitting the crust.
Several papers by geologists were consulted for this summary. While, admittedly, I do not own a geological map of Siberia, and none may be for sale in the West, the geological foundations of these various geographical features should be easily ascertainable by professional geologists. The entire track is studded with mining treasures of all sorts, so perhaps this explains why the track is not better known until now.
Hello Dr. Burchard,
You may remember we corresponded briefly a few years ago concerning my research efforts in Palo Duro Canyon Texas. However at the time I was working on the Traissic sediments rather than those of the Permian and knew little about radiometric ages of them or any influence massive basalt flows may have had on them.
I am writting because I have recently formed my own company and significantly increased my income and so in the future may have funds to finance some work and the time to undertake it. Nothing definate and certainly nothing before late 2012 but I just read an article on flood basalts and thought of you and your research and thought I should drop a line to let you know I may renew my Palo Duro Canyon research and may extend it down into the Permian.
Also in the coming months I will be working with others preparing materials for an AAPG field seminar to be held in Palo Duro Canyon in late August or early Sept of 2012 and any information you might have on the Permian sediments of this area might be appropriate for inclusion. Our concentration will be on petroleum exploration applications of the ideas we can illustrate with the rocks in the canyon but I intend to provide a solid background of academic data relevant to the canyon as well.
Darryl Maddox (retired from Amarillo College)
Wellsite Geological Services
[email protected]
806-282-0328
Daryl,
thanks for the msg (now dated, sorry). The point itself is mute as Chatterjee reports that the top of the Permian is nowhere exposed in Texas, more precisely there is not any spot where there is conformable contact between the Permian & Triassic. –
Here is an abstract about the precise timing of the end-Permian events from a paper that just appeared in PNAS Early Edition.
Burgess et al, abstract:
The end-Permian mass extinction was the most severe loss of
marine and terrestrial biota in the last 542 My. Understanding its cause and the controls onextinction/recovery dynamics depends on an accurate and precise age model. U-Pb zircon dates for five volcanic ash beds from the Global Stratotype Section and Point for the Permian-Triassic boundary at Meishan, China, define an age
model for the extinction and allow exploration of the links between global environmental perturbation, carbon cycle disruption, mass extinction, and recovery at millennial timescales. The extinction occurred between 251.941 ± 0.037 and 251.880 ± 0.031 Mya, an interval of 60 ± 48 ka. Onset of a major reorganization of the carbon cycle immediately precedes the initiation of extinction and is punctuated by a sharp (3‰), short-lived negative spike in the isotopic composition of carbonate carbon. Carbon cycle volatility
persists for ∼500 ka before a return to near preextinction values. Decamillenial to millennial level resolution of the mass extinction and its aftermath will permit a refined evaluation of the relative roles of rate-dependent processes contributing to the extinction, allowing insight into postextinction ecosystem expansion, and establish
an accurate time point for evaluating the plausibility of
trigger and kill mechanisms.