BREAKING NEWS: Giant ammonite discovery

Phil

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Another question for Dr Monks;

Neale,

I have been looking at some charts of the evolutionary patterns of extinction and diversification of ammonoid orders and sub-orders and have noticed that at a date of approximately 100-95mya some of the ammonoid orders began to diversify and increase in their number. I am thinking here of the sub-orders Turrilitaceae, Desmocerataceae, Hoplitaceae and the Acanthocerataceae. Could it be that the abundance of copepods that fed on the nano-plankton that caused the chalk to be deposited, provided an increase in food stocks for the ammonoids? With plenty of food, could this have provided a catalyst to diversification as population stocks began to increase? Or is the increase in the number of families within these sub-orders attributable to a different cause?

Attached is a photo of an ammonite I have from the local chalk; somewhat less impressive than the Parapuzosia, and somewhat worn. It is a quite large specimen and I have not really been able to identify it. I think it may possibly be Schloenbachia; it’s about the right age, but I’m not sure if that species is found in the chalk or not.

Cheers,

Phil
 

Architeuthoceras

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Phil, a question or two about the chalk, is it soft like the chalk you write on a chalkboard with, or is it harder than it looks? How fast does the chalk erode? How long do you think that fossil will last where it is? Are you in danger of being washed into the channel?

Nice fossil by the way.

:ammonite:
 

Phil

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Kevin,

As far as I can determine the entire sequence of Lower-Upper Chalk is exposed at Dover; the cliffs reach a height of 250m or more in places. Most of the most interesting fossils come from the Middle and Upper Chalk. The Upper Chalk is particularly notable for the bands of flints nodules that run along its course; these silaceous concretions tend to form around the remnants of ancient creatures such as echinoids or crustaceans.

The chalk here is quite soft; it is frequently used by local kids for grafitti; at least it washes off! This means, of course, that it erodes quite easily. Indeed, in April 2000 and in January 2001 we had two massive cliff falls in the area; something approaching 20,000 tons of chalk came crashing down that April when a section of chalk 600ft long by 300ft high disintegrated between Dover and St Margaret’s Bay a couple of miles to the north of Dover taking with it a cliff path.

You can see images of the fall taken a few moments after it happened here:

http://www.rippledown.com/cliff-fallphotos.html

I would hope that the Parapuzosia is removed from the cliffs at Margate as soon as possible for this very reason; the weather around this corner of England is extremely unpredictable, it is possible that the ammonite may still be sticking out of the cliff in ten years time; though by the same measure, we only need a few weeks of rain followed by freezing weather this winter and the cliffs could be cracked open by the expansion of the frozen water in the saturated chalk, as is believed to have happened at St Margaret’s Bay. I personally do not fancy the ammonites’ chances more than a couple of years, I would hope it is removed soon.

No, there is no danger of me being washed out to sea, sorry! Dover is built pretty much in a river valley that forms a natural gap in the chalk. There are few residential buildings up on the cliffs for that very reason. The seafront is protected by a massive harbour wall; but that’s another story……

:nautilus:
 

Phil

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This ammonite appeared again on a local news program last night, depicting some of the best fossil hunting areas in North-East Kent. The ammonite does not seem to have weathered out at all since this was initially reported in September 03. It's a pity that it has not been recovered yet as the exposed surface would be regularly bashed with rain and gales, and is doubtless decaying.

Retrieving it would be a monstrous job, the thing is embedded half-way up a cliff, and is probably well over a meter in diameter.

Here's a picture of it now, again, I apologise for the poor quality, that's what happens if one tries to photograph the television screen off a paused video tape. I must buy a DVD recorder one of these days!

 

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Feelers

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Seems a shame to have it just erode away up there. Perhaps there's a museum that would be interested? Unless of course you feel like donning your climbing gear. :biggrin2:
 

OB

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What would that drillhole have been caused by? Buccinum giganteum: the until very recently (this afternoon) unknown giant cretaceous whelk? :biggrin2:
 
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that would be..like...huge. And that shell looks rather tough..even for a large radula equipped ceph. Maybe some erosion/abrasion cuasing a hole to form before it fossilised?
 
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Feelers said:
Seems a shame to have it just erode away up there. Perhaps there's a museum that would be interested? Unless of course you feel like donning your climbing gear. :biggrin2:

Y'all know me. Know how I earn a livin'. I'll catch this ammonite for you, but it ain't gonna be easy. Bad ceph. Not like going down to the pond and chasing bluegills and tommycocks. This ceph, swallow you whole. No shakin', no tenderizin', down you go.
 

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