POSSIBLE LONDON CLAY MICRO-TEKTITES, UNITED KINGDOM

?? Lower Eocene Age

LATEST: A zero geologic age by isotopic dating in 1994, which has recently come to my attention, leaves doubt in the minds of many as to whether these objects are genuine micro-tektites.

In favour of these being genuine micro-tektites:

1. The morphologies very closely match those of proven micro-tektites. Genuine micro-tektites often display the fused characteristics noted in the London Clay specimens.
2. The chemical composition is atypical for tektites/micro-tektites, but when one considers that the likely impact site (Silverpit Crater, North Sea) was in the upper Cretaceous chalk, which is 98% CaCO3, the chemical composition does not appear abnormal. Other impacts in limestone-rich deposits, including the Chicxulub Crater, have produced micro-tektites rich in CaO. Please see the table below.
3. Michael Daniels, the finder of the micro-tektites is confident in his collection and processing techniques and does not believe these micro-tektites are contaminants from either the collection area/technique or laboratory. Michael Daniels comments ‘The tektites came from a pure accumulation that first saw the light of day when I removed it from the deposit where it had rested UNDISTURBED since it was interred circa 55 million years ago. It was placed in a bag that suffered no alien intrusions and, once subjected to a thorough natural drying process, was reintroduced to water where the clay disintegrated allowing the residues to be caught in sieves of varied mesh sizes.’
4. Michael Daniels found these micro-tektites associated with vertebrate fossils. These fossils are genuinely and indisputably from the London Clay of Lower Eocene age. It has been suggested that the vertebrate fossils may have been swept into the London Clay Sea by giant impact generated Tsunami – this latter interpretation is plausible, but obviously highly speculative.
5. Michael Daniels has found 3 separate occurrences, with one sample containing over 100 of these objects. Findings are therefore not based on a single sample. It would, however, be good to repeat the finds, but as these objects occur in pockets this may prove difficult.


Against these being micro-tektites:

1. In a test using Brent Dalrymple’s laser 40Ar-39Ar laboratory in Menlo Park, the spherules were found to not contain any radiogenic 40Ar. It was concluded that they had a zero geologic age. In 1994 Glen A. Izett of the USGS noted that if the spherules were tektites of Eocene age they should contain appreciable 40Ar from the radioactive decay of 40K. Incidently, late Eocene tektites were dated at 34.5 Ma in the same analytical batch. He concluded that ‘from this experiment…the spherules are not tektites, if they were tektites their glass should accumulate and retain radiogenic 40Ar.’
2. Michael Daniels commented ‘I think it important to mention that I did retrieve a solitary, but typical, glassy example, discovered in a quantity of beach concentrate removed from below the cliffs of Warden Point, Isle of Sheppey, Kent, middle and upper London Clay. This appears to be the broken half of a dumbbell shaped object and although similar in size to those from the Naze, it has a slightly greenish colouration.’ The fact that a micro-tektite is occurring at a significantly higher stratigraphic horizon can be explained by either reworking or may point to contamination. It certainly does not fit in neatly, where micro-tektites would be expected in a single stratigraphic layer. As a micropalaeontologist, however, I am aware of how easily microscopic objects may be reworked into younger sediments. Equally I am aware of how easily contamination can take place.

To conclude: Despite strong superficial evidence suggesting that these are micro-tektites, it seems very difficult to get around the fact that these tektites have a zero geological age based on the 40Ar-39Ar dating method. I feel that these are such a strong candidate for micro-tektites that they are surely worthy of further investigation. It would be good to see if another dating method could be applied to the specimens to confirm the zero geologic age. If a zero geological age proves correct then these specimens cannot be considered Lower Eocene micro-tektites. Also, I would like to see, first hand, the exposure from which these micro-tektites are reported to be derived. If these are not micro-tektites it is probable that they are contaminants from a man-made source, but to find over 100 in a sample would imply major contamination – something Michael Daniels insists could not have happened. Another avenue worthy of investigation would be the H2O content. If these are true micro-tektites then an extremely low water content would be expected.

  

BELOW   A table detailing the composition of the London Clay 'micro-tektites' and comparing them with other high CaO confirmed micro-tektites, other more typical micro-tektites and terrestrial obsidian. Data extracted from McCall, 2001. Thanks to Peter Green for drawing attention to the fact that high CaO tektites exist.

 

 SiO2

Al2O3 

Fe2O3 

FeO 

MgO 

CaO 

Na2O 

K2O 

TiO2 

MnO 

H2O 

London Clay 'micro-tektites'

31.57-32.30

15.74-16.00 

inc. in FeO 

0.26-0.27 

5.60-5.83 

40.06-40.23 

0.26-0.27 

0.71-0.78 

0.61-0.65 

0.85-0.93 

 --

 Beloc Haiti micro-tektites (Ca-Rich Range) (From Chicxulub Crater)

 44.40-49.06

11.70-13.20 

inc. in FeO 

4.80-5.14 

4.09-4.41 

24.54-30.17 

2.01-2.10 

0.48-0.63 

0.64-0.66 

0.10-0.16 

 --

 Senzielles, Belgium, micro-spherules (Ca-Rich Average) (Upper Devonian)

44.78

20.10

inc. in FeO 

 5.40

2.10 

23.11 

0.55 

2.16 

0.60 

0.15 

0.009 

 Mimbal, Mexico, micro-tektites (From Chicxulub Crater)

52.20-66.20

12.40-18.70 

inc. in FeO 

4.20-12.00 

0.40-9.30 

0.80-23.00 

0.10-3.85 

0.58-3.70 

0.60-0.90 

0.02-0.14 

-- 

 Microtektites from Pliocene Eltanin Structure, South Pacific Ocean

41.11-49.88

7.60-17.61 

 inc. in FeO 

9.84-18.03 

9.86-18.55 

7.62-15.20 

1.11-9.10 

0.01-0.11 

0.30-0.61 

0.24-0.53 

-- 

 Qidong, China micro-spherules (Upper Devonian)

 61.77

21.82 

 inc. in FeO 

1.48 

2.91 

5.15 

2.48 

3.23 

0.55 

0.04 

-- 

 Australasian micro-tektites (Central Indian Ocean)

66.70-70.60

12.20-16.90

 inc. in FeO 

3.96-7.33

1.95-6.94

0.87-4.33

0.51-1.74

0.64-3.46

0.62-0.92

 --

 --

North American micro-tektites (Chesapeake Crater assoc.) 

 70.70

15.40 

 inc. in FeO 

 5.00

1.77 

1.61 

3.02 

1.05 

0.80 

-- 

-- 

Ivory Coast micro-tektites 

 65.60

15.60 

 inc. in FeO 

6.90 

4.60 

1.40 

1.80 

1.90 

0.70 

--

-- 

 Barbados micro-tektites (Chesapeake Crater assoc.) 

76.0-84.2

10.4-13.5 

 inc. in FeO 

1.48-3.68

0.45-0.99

0.20-0.86

0.60-1.28

1.77-2.86

0.49-0.77

 --

 --

 Terrestrial Volcanic Obsidian (Johanssen, 1932)

 73.84

13.00 

1.82 

0.79 

0.49 

1.52 

3.82 

3.92 

0.14 

-- 

0.53 

 Terrestrial Volcanic Obsidian (Glass, 1990)

 74.02

11.38 

1.36 

2.23 

0.14 

0.48 

5.21 

4.28

0.18 

-- 

-- 



  

HISTORICAL:

It was reported by Peter Green and Dr. Adrian Rundle in the Geologists' Association Magazine that Mike Daniels discovered millimeter sized glassy spheres in the 1970's. These glass spheres were found in the Lower Eocene London Clay at Walton-on-the-Naze, Essex, England. Furthermore, I understand the possible microtektites were found in a fossil -rich pocket, that has now been totally removed. The fossils included birds, small horses, tapir and small insectivores. These had obviously been washed into the London Clay sea, possibly catastrophically by means of impact generated tsunami.

Walton-on-the-Naze, Essex has exposures of uppermost A1 and basal A2 divisions of King (1981). These divisions fall in the basal Ypresian, basal Lower Eocene age. It has been suggested that these tektites are related to the disputed Silver Pit Impact Crater in the North Sea Basin.

An image of the possible microtektites shows micro-dumbells, teardrops, spheres and ovals. The microtektites appear to be typically 1mm in diameter, but some 'stretch' micro-dumbells appear to be about 4mm in length.

 

ABOVE:   Possible microtektites from the London Clay. The scale at the top = 1mm subdivisions. Image from Green and Rundle 2006. Reproduced with kind permission from Peter Green and Michael Daniels.

 

  ABOVE: Possible London Clay microtektites. Image courtesy of Michael Daniels.

 

ABOVE:   Possible London Clay microtektites. Image courtesy of Michael Daniels.

  

ABOVE:   Possible London Clay microtektites. Image courtesy of Michael Daniels.

  

ABOVE:  Possible London Clay microtektites. Image courtesy of Michael Daniels.

 

Some historical notes on these tektites were made by the finder Michael Daniels and he has kindly given me permission to reproduce them. These are the original unedited notes:

 

TEKTITES - DOCUMENT DISCUSSING THE DISCOVERY OF GLASSY PARTICLES FOUND WHEN PROCESSING NAZE ACCUMULATIONS


Over a relatively short period in the late 1970’s whilst screening quantities of silt acquired from the marine lower London Clay of Walton-on-the-Naze, Essex, south-east England (lower Eocene) in search of vertebrates, I found several examples of what I assumed to be glassy particles of volcanic origin. Since that time, although I must have processed in excess of 10,000 kg of what was once the ancient seabed, the finds have never been repeated.

A succession of thin sedimentary units at Walton suggest deposits laid down under the influence of fast changing conditions during a period of considerable tectonic upheaval. Underlying these strata and inaccessible at the Naze, there occurs a sequence of beds containing abundant evidence of volcanic ashfall 1,2. This section is best seen in certain estuary exposures, particularly that bordering the River Stour at Wrabness, some 11 km, (7 miles) north-west of Walton.

Thus when I discovered these curiously shaped glassy objects, I simply concluded that they probably
represented continued upward proof of volcanism. The possibility that, in their rarity and in their form, this might point to some precipitant or totally unconnected event, was certainly not appreciated at the time.

In one of three separate occurrences, over a hundred of these objects were gathered together in one batch of sieved residues. They assumed a wide diversity of form including spheres, dumbbells, tear, ovate and sausage shapes, rods and globular masses some of which appear to be of several individual particles welded together. All are generally of light amber colouration, many clear and transparent, some with internal voids.

Under examination by other more informed authorities, I accepted the designation offered that such tiny objects were examples of tektites. Of late I have come to realize that if this description is correct, then my regarding them as being from a straight forward terrestial volcanic source may be in doubt. The origin of tektites is apparently still cause for considerable and ongoing debate, with strong claim that these variously shaped particles may have extra-terrestial connections, either formed under intense heat when some celestial body struck the earth’s surface, or alternatively, similar impact upon the moon which caused molten material to be thrown out into space, some to reach our planet.

Quite a lengthy encylopaedia appraisal 3 has provided a useful source of enlightenment and very recently the television series ‘Dinosaur Footprints’ referred specifically to the importance attached to tektites found in strata at the KT boundary and the possibility that these could provide vital evidence of a meteorite strike that may have created the conditions that led to the extinction of the dinosaurs.

Supporters of such a scenario might take comfort from the factors concerning the Naze and events that occurred in a period of the early London Clay times. Here again there is incontrovertible proof of some cataclysmic event, this time apparently annihilating the avian community particularly, over a wide area. Bird fossils are abundant in the strata at the Naze and where it has been possible to gain access to similar horizons elsewhere, some at a considerable distance from the coastal site, they appear with equal frequency. Always at each locality, there is evidence of massive outwash from the land with an abundance of plant debris. Not infrequently at the Naze, winnowed patches resemble embers of burnt foliage.

If it is now correct to refer to the objects as tektites, micro-tektites in this case, and confirm that such are produced as a result of a collision of some cosmic entity with the Earth’s surface, then the implications are obvious and far reaching. Consideration of the North-western European, North Sea basin as a possible impact site must follow. This deep sediment filled depression with its surrounding arc of sites producing evidence of volcanism, these stretching from the Skagarrak region of Denmark, through north Germany and the low countries, thence across the British Isles to Scotland and Antrim in Northern Ireland, are apparently all of roughly Ypresian age. If no more than to do with coincidence, this factor is still intriguing.

I had not lost sight of the need to explain how the particles appeared above the main ash layers if they are to be considered as relating to the primary cause of the ensuing volcanic event. Reworking of the material from the original ‘strewn field’ may be a possibility, though admittedly speculative. Adding further to the discussion on this aspect, I think it important to mention that I did retrieve a solitary, but typical, glassy example, discovered in a quantity of beach concentrate removed from below the cliffs of Warden Point, Isle of Sheppey, Kent, middle and upper London Clay. This appears to be the broken half of a dumbbell shaped object and although similar in size to those from the Naze, it has a slightly greenish colouration.

This account cannot be concluded by my making any claim to have shed light on the mystery of tektite origin. The appearance of such bodies now in south-east England from two horizons in lower Eocene strata, these vertically separated by some 80 metres (262 feet), which in terms of sedimentation must represent a considerable period of geological time, perhaps adds to the confusion rather than resolving any of the problems.

It is still possible the particles are simply rather rare products of natural earthly volcanic action, although in reference to available documentation on the subject, the concensus seems less favourable to this explanation partly based on the aerodynamic considerations. Alternatively, we are left to further question the impact theory or explore the realms of cosmology to find some viable answer.

1 ELLIOTT, G.F. 1971 Eocene volcanics in south-east England. Nature, Phys. Sci. 230, 9.

2 KNOX, R.W. O’B & ELLISON R.A. 1979. A lower Eocene ash sequence in S.E. England. Jl. Geol. Soc. Lond. 136, 251-3.

3 Encyclopaedia Britannica 1990. Micropaedia Vol.11. 607-9.

M. C. S. D. 22nd September 1993



Since the above was written I have continued to seek enlightenment as to the likely identity of the particles. Various authorities contacted have offered conflicting views. Some believe in the authenticity of the exquisitely formed objects, see accompanying photograph, others consider they must be modern contaminate of some kind. This observation based completely on the radiometric test to which 20 or so were subjected proving negative. The chemistry and appearance, nevertheless, being quite in keeping with that of fully verified micro-tektites.

Now in 1997, I find myself still wholly confident in the importance of these tiny particles; certainly I feel able to dismiss any argument that they are in any way artificial. Those who I have escorted to inspect the remarkable Naze locality can easily see why I am resolute in defending the objects as genuine and of London Clay age. The energetic forces of sea and weather to which this exposed coast is subjected, would, within the period of one or two tides, severely abrade or more certainly, render them completely unrecognizable from the pristine state of those in my possession.


M.C.S. Daniels 12th August 1997

I asked Michael Daniels as to whether the vertebrate fossils were articulated or not. This is his reply (May 2007):

There is a multiplicity of vertebrates from the Naze at Walton. Remains of fishes the most abundant, then BIRDS followed by reptiles, mostly turtles but including some snakes. Add to that amphibians, a few, likewise the MAMMALS. The last named represented by several incredible relics. The way these items are deposited, the birds, mammals in particular, is highly curious. Many specimens are found with no indication of articulation. Usually the bones are clustered together in disarray and there is possibility that they may have been the discarded element of some marine creature's meal, following the carcasses being swept out to sea by detritus loaded estuarine currents. The abundance of shark's teeth in Naze plant rich 'pockets', might suggest some 'feeding frenzy' may have taken place amongst these scavengers.'

I would like to further comment that if these fossils were rapidly buried in tsunamis generated deposits one might expect them to articulated. Having no indication of articulation does not exclude the possibility of a catastropic event, but it also opens up the possibility that palaeo-submarine erosion removed the fine sediment, leaving a concentration of bones.

 

Are you an expert/experienced in microtektites - What do you think?

Contact me at aubrey@tektites.co.uk and I'll pass relevant emails onto Michael Daniels.

 

References:

Collinson, M. E. 1983. Fossil Plants of the London Clay. The Palaeontological Association, London.

?Green, P.?   1998. Fossils of the L. Eocene London Clay from Walton-on-Naze - Essex. (Booklet including microtektite section).

Green, P. and Rundle, A. 2006. "Small Contributions" - how the GA is advancing micropalaeontology. The London Clay at Walton-on-Naze - Essex: Evidence for a tsunami. Magazine of the Geologists' Association. Vol. ? No.? (2006).

King, C. 1981. The Stratigraphy of the London Clay and associated deposits. Tert. Res. Spec. Pap. 6, 1-158

McCall, G. J. H. 2001. Tektites in the Geological Record. The Geological Society, London.

  

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