Igneous History of British Isles Won't Fit Into Global Flood

Copyright 2004 G.R. Morton  This can be freely distributed so long as no changes are made and no charges are made.

One of the things which shows time in the record is the volcanism which occurred around the British Isles at the time of the continental breakup. The volcanism occurred as the earth's crust between North America/Greenland and England/Ireland was ripped apart when continental drift split Pangea. This volcanism also shows that Baumgardner's runaway subduction is false since it is unable to account for the timing of the volcanism.

This is a seismic line from the northern Irish Sea and shows several igneous dykes which have intruded into the strata. A dyke is an finger or sheet of igneous material which is forced through the sedimentary column but is not parallel with the sediments. The blue arrows mark the dykes which are basically at an angle of 8 degrees. (It doesn't look like it on the seismic line but rough calculations show that this is the true angle. The The sedimentary material was deposited basically horizontal and then a dome formed. The reason we know that the sediments were originally laid down flat is because the sedimentary boundaries are parallel. If there had been an anticline (a hill) in the middle of the seismic when the sediments were deposited, the sediments on top of the anticline would be thinner. Since they aren't we know that the formation of the anticline (hill) occurred after the deposition.

But we also know that the dyke intrusion occurred after the sediments were deposited. The marked intrusions are thin sheets of igneous material. This material could not have been there prior to the sedimentary material. Mechanically it would be impossible to support a sheet of basalt at a 8 degree angle over a horizontal distance of 4800 meters and a height of 700 meters. This is known because at the top of the section are shotpoint numbers. Each 100 numbers is about 1200 meters and the vertical climb is from about 1.2 seconds deep to .5 seconds deep. Velocities in seas around England yield about 1 meter per millisecond height, so that means about 700 meters vertical height separates the top of the dyke from its base.

One thing to notice is that the dykes intrude almost the entire sedimentary column. Since as we noted, the dykes can't be emplaced prior to the emplacement of the sedimentary material (for mechanical reasons), it means that the volcanism occurred after the deposition of the sediments. That observation destroys Baumgardner's runaway subduction theory. Why? Because Baumgardner has the runaway subduction act at the start of the flood, indeed, it is the cause of the flood. But when the continents split, volcanism would be expected along with intrusions such as dykes. But the data shows that the intrusions associated with continental breakup occurred at the end of the flood, when nearly all the sedimentary material was already deposited. Thus runaway subduction postulates the intrusions at the wrong time for the observational data.

Another thing, the volcanism both on Greenland and Scotland, date around 55 million years old. The Skaergaard Intrusive complex yields K/Ar dates of that age (Hirschmann 1997) . But that is also the age of the intrusion on the Isle of Mull (Musset, A.E., 1986), the Giant's Causeway on Eire, and the Balder Tuffs of the North Sea (Jager et al, 1993, p. 60). More on the Balder Tuffs later.

The early Tertiary dyke system is quite extensive. The picture below shows the extent of onshore Tertiary dykes.

The picture above misses the dykes which exist in the Irish Sea between England and Eire.

The dark NW-SE linear features are the magnetic signature of the Tertiary Dykes. Remember, from the seismic line, all this volcanism occurred AFTER the deposition of most of the sediments.

One other interesting item in the 2nd picture above. In rocks which contain uranium, the radioactive decay produces fission tracks, which can be observed under the microscope. These fission tracks are the record of how much radioactivity has occurred. The more tracks (or rather more correctly) the more dense the tracks are, the older the rock is. Fission tracks represent damage to the crystals in the rock. Fission tracks can be destroyed if the rocks are reheated. All over the Scottish highlands, most fission track ages yield ages of 300 million years or so.

Note the dark circles on the Isles off the coast of Scotland in the 2nd picture above. The northernmost one is on the beautiful Isle of Skye, a place worth visiting. Those black circles are batholiths which were intruded into the sediment 55 million years ago during the opening of the Atlantic Ocean. Like the Giant's Causeway in Eire and the Skaergaard intrusive in Greenland and the Balder Tuffs, everything dates to around 55 million years. The dates just mentioned are due to K-Ar ages mostly.. The intrusive there as elsewhere, heated the local rocks which surround the batholith. In the case of the Isle of Skye intrusion, the heating zone extended 12 kilometers away from the batholith. The heating destroyed the fission tracks which had been in the rocks. And very interestingly, when one fission track dates the rocks within 12 km of the Isle of Skye batholith, the fission track yields an age of 55 million years or so. Below is a picture showing the fission track ages around Scotland. The upper picture is of all of Scotland and the lower is focused in on the Skye batholith.

In the lower picture you can see on the Isle of Raasay the 293 million year fission track date which is outside of the 12 km annealing area.
One other thing about the volcanics is that it is known that 1-2 kilometers of rock have been eroded off the Scottish Highlands since the emplacement of the batholith. This is not inconsistent with the dykes mentioned earlier which are emplaced after most of the sedimentation took place. The Scottish Highlands of the Western Isles have very little sediment cover. Most of the rocks are igneous, being older than the Tertiary Period.

"Fission track data from the Scottish Highlands (Hurford 19776), Skye area (Lewis C I ul. 1992) and the onshore margins of the Moray Firth have ages c. 200-300 Ma. suggesting that these areas could not have been uplifted more than 2km during the Tertiary. Mass balance calculations suggest that the entire volume of Paleogene submarine fan sediments in the North Sea could be accounted for by uplift of the East Shetland Platform and the Scottish Highlands of less than I km. The Caledonides of the Highlands provided a persistent sand source of the North Sea submarine fans. Further south. in northern England. the main eroded intervals were probably Chalk. Jurassic shales and Carboniferous Limestone. The lack of sand in these sections explains. in part. why there are no Tertiary submarine fans in the Southern North Sea.

"The Thulean Volcanism was a result of 'hot spot' activity related to the opening of the North Atlantic. The 'hot spot' was responsible for the creation of the Greenland-Faeroe Ridge and is presently situated under Iceland (White 1988). K-Ar datings from Evens et al. (1973) indicate that the Thulean volcanism lasted from 47-70 Ma. However, Mussell et al. (1988) suggest a rather shorter time span, from 52- 63 Ma, based on more recent datings including Ar-Ar ages. However, both authors agree that the peak of activity occurred around 59-60 Ma. There is a second clear peak in volcanic activity around 54-55 Ma, close to the age suggested for the tuffs of the Balder Formation (Knox and Morton 1988). By this time. it is likely that volcanic activity had become markedly more explosive, as most of the younger ages are derived from acid bodies such as the Red Hills of Skye (Mussett et al. 1988). Peaks in volcanic activity correlate well with the relative sea-level curve derived from this study." Jager et al, 1993, p. 60)

Now, with all this volcanism, one might expect that there would be volcanic ash deposited over a wide area. There was. In the North Sea, I used to drill wells through the Balder Tuffs. A Tuff is a volcanic ash that has been turned into lithified rock. Anderton writes:
"The Balder Formation is also important in that it records the most intense phase of volcanic activity seen in the North Sea. In the lower part of the unit there are hundreds of individual ash layers, mostly only millimeters to centimetres thick but forming a total thickness of over 8 m at the northern end of the North Sea Basin, and known informally as the Balder Tuff. This ash unit is an important marker throughout the North Sea as it produces a distinctive gamma or sonic bow on well logs. The total ash thickness declines toward the south-east, but ashes are found as far away as southern England, Germany and Denmark. The ashes are of Theoleiitic-basalt composition and were probably erupted from a large volcano, somewhere along the North Atlantic rift, north-west of Britain" R. Anderton, "Tertiary Events: The North Atlantic Plume and Alpine Pulses", in Nigel Woodcock and Rob Strachan, editors, Geological History of Britain and Ireland, (London: Blackwell Science, 2000), p.383

The problem all this presents to the YEC is:
1.The radioactive dates are in agreement
2.Runaway Subduction can't be the cause of the flood
3.the intrusives are after most of the sediment has been deposited, and thus the opening of the Atlantic can not have occurred during the flood in most flood models
4.The YEC must explain how hundreds of individual ash falls occurred in such a short time frame
5.The erosion of 1-2 kilometers of sediment from the very hard Scottish Highland rocks must have occurred after the flood and within the past 4000 years, but there are archaeological sites from that age in Scotland on the present land surface.
This data simply doesn't fit into a YEC scenario.

Hirschmann, M.M.; P.R. Renne; and A.R. McBirney, 1997,
"40Ar/39Ar Dating of the Skaergaard Intrusion,"
Earth and Planetary Science Letters, v. 146, p. 645-658.)
Jager, D. Den Hartog ' M. R. Giles' and G. R. Griffiths, "Evolution of Paleogene submarine fans of the North Sea in space and time," From Petroleum Geology of Northwest Europe: Proceedings of The 4th Conference (edited by J. R. Parker) 1993 Petroleum Geology '86 Ltd. Published by The Geological Society. London, pp. 59-71., p. 60)
Musset, A.E., 1986, 40Ar-39Ar step-heating ages of the Tertiary igneous rocks of Mull, Scotland: Journal of the Geological Society of London, v. 143, p. 887-896.

No comments:

Post a Comment