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Showing results for tags 'hirnantian'.
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Oxytropidoceras posted a topic in Fossil NewsThere is a series of open access papers about what caused the Late Ordovician mass extinction. They are: Bond, D.P. and Grasby, S.E., 2020. Late Ordovician mass extinction caused by volcanism, warming, and anoxia, not cooling and glaciation. Geology. https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G47377.1/586486/Late-Ordovician-mass-extinction-caused-by Mitchell, C. E., and Melchin, M.J., 2020. COMMENT: Late Ordovician mass extinction caused by volcanism, warming, and anoxia, not cooling and glaciation. Geology https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G47946C.1/587311/COMMENT-Late-Ordovician-mass-extinction-caused-by Bond, D.P. and Grasby, S.E., 2020. REPLY: Late Ordovician mass extinction caused by volcanism, warming, and anoxia, not cooling and glaciation. Geology. https://pubs.geoscienceworld.org/gsa/geology/article/doi/10.1130/G47984Y.1/587312/REPLY-Late-Ordovician-mass-extinction-caused-by Wang, G., Zhan, R. and Percival, I.G., 2019. The end-Ordovician mass extinction: A single-pulse event?. Earth-Science Reviews, 192, pp.15-33. https://www.sciencedirect.com/science/article/pii/S0012825218305099 https://www.researchgate.net/publication/331275476_The_end-Ordovician_mass_extinction_A_single-pulse_event https://www.researchgate.net/profile/Gx_Wang2 Yours, Paul H.
I found this in an old quarry at the foot of the Old Man of Coniston, Cumbria, England about 30 years back. It's from the Ashgill Shales, so is very uppermost Hirnantian, Upper Ordovician. It was a dome shape but broke during extraction,to reveal a smaller dome within the dome and so on, but is built up of layers and layers though the 'tubes' running through it also continue upwards and outwards from the base. Is it Fisherites ? It's about 3.5 cm in diameter but was a little bit bigger. Thanks for any help. Top : Side : Side and base : Base :
Today I decided to go and visit a roadcut that I red on one of the Silurian literatures I got my hands on (a big thank you to those that led me to those PDFs relating to the geology of the Niagara Escarpment). It turns out the roadcut on the Niagara Escarpment is near my home which is a pleasant suprise to me, considering that I have been disappointed by the Queenston formation. This roadcut is actually several exposures that run on an access road that can lead one to the upper part of Hamilton, Ontario. Here is the exposure I decided to explore. I chose this exposure as the access is a busy boulevard with cars driving by with no sidewalks and pedestrians. I had several people honk and call out to me as I was exploring the site. Maybe I should have worn a safety vest of some sort? Is that even necessary?
JUAN EMMANUEL posted a topic in Fossil Hunting TripsToday I managed to explore and observe an exposure of the Queenston formation up close here in Hamilton, Ontario. I chose a site along the Red Hill Valley Expressway that was easy to access and get down to for a close look. The creek is right next to the highway. I have always passed by this exposure and anticipated the day I'll be able to observe it. The Queenston formation is the last Ordovician formation in south-western Ontario before the rocks hit the Silurian age. The Queenston is what overlains the Georgian Bay formation, the formation I use to hunt in frequently in Toronto, Ontario. This is Red Hill Creek as it passes by next to the Highway.