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Post by ammocarbsteve on Mar 8, 2011 4:16:19 GMT -5
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Post by archimedes on Mar 14, 2011 12:55:47 GMT -5
Pictured is a Lepidodendron standing, 20 ft+ tall, on top of a caol seam in a local strip mine. Lower Pennsylvanian in North Alabama Attachments:
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Post by ammocarbsteve on Mar 14, 2011 13:55:50 GMT -5
archimedes.... 20 ft!.... Thats a serious stump.... I have never seen any that tall before... The sediments must of been deposited quite quickly to preserve such a massive trunk... I always thought the 4-6 ft ers I find were possibly casts that were filled from above by sediments after the trunk had rotted... but maybe other methods of preservation are responisible if preservation of trunks this length are possible... Thanks for sharing it... Brilliant...
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Post by pleecan (Peter Lee) on Mar 14, 2011 14:13:55 GMT -5
Wow! 20 ft..... that is a monster fossil!!!
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Post by archimedes on Mar 14, 2011 20:40:41 GMT -5
This tree is sitting directly above the coal seam. When we seen this, we were all wondering 1) how long it took to bury this tree, and 2) how long the tree will stand before it rots and falls over. It is apparent that a quick change in the basin or a rapid change in sea level occurred.
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Post by Joe Botting on Mar 14, 2011 20:58:02 GMT -5
That's astounding. Not sure on the length of time they could remain upright, but don't forget these are nowhere near as robust as modern trees, and they lived in hot, humid conditions... I honestly don't think a eustatic or normal tectonic change would have been fast enough for this, and if it was sea level rise then you find marine fossils in the beds around it. Lucy suggests a large earthquake as a way to drop the area suddenly by several metres (and also leading to high sediment input), and another option is slumps or mudslides (any volcanism in that area at the time?). It would be very interesting to see the state of any fossils in the mud surrounding the trunk at different levels...
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Post by ammocarbsteve on Mar 15, 2011 4:01:51 GMT -5
Heres the tallest tree I have come across....Maybe 10 - 12 ft I cant honestly remember.... So we are dealing with rapid burial really to create the cast... I suppose the best place to be for rapid deposition of sediments is in the delta region of a 'super continent'....any major event, even inland, heavy rain etc could drum up the forces required to do this... I'm supprised considering the trees are not 'woody' they are not leaning in a consistent direction pushed by the force of the deposition... Maybe the burial was more gentle and gradual and I wonder if these trees could withstand partial burial up the trunk where many of their 'woody cousins' cant today... Attachments:
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Post by pleecan (Peter Lee) on Mar 15, 2011 5:06:29 GMT -5
What an interesting thread... thanks everyone for your contributions!
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Post by ammocarbsteve on Mar 18, 2011 6:34:20 GMT -5
Tim must be busy... I'll post a few more bits of Lepidodendron... Attachments:
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Post by ammocarbsteve on Mar 18, 2011 6:35:02 GMT -5
cont... Attachments:
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Post by ammocarbsteve on Mar 18, 2011 6:35:37 GMT -5
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Post by ammocarbsteve on Mar 18, 2011 6:36:49 GMT -5
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Post by ammocarbsteve on Mar 18, 2011 6:37:38 GMT -5
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Post by ammocarbsteve on Mar 18, 2011 6:38:22 GMT -5
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Post by ammocarbsteve on Mar 18, 2011 6:39:14 GMT -5
cont...One of my favoroutes... Attachments:
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