Traces of `` Wandering rocks '' that move unknowingly in fossils 200 million years ago may unravel the mystery of dinosaur extinction
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A trace of the phenomenon “ Wandering rocks ” in which a huge rock weighing more than 100 kg moves unpredictably was discovered from a fossil 200 million years ago. The research team claims that the traces of this wandering rock will unravel the mystery of “the end of the Triassic dinosaur mass extinction ”.
AGU Fall Meeting 2019
https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/580376
Sailing Stone Track Discovered 'Hiding in Plain Sight' in Dinosaur Fossil
https://blogs.ei.columbia.edu/2019/12/09/sailing-stone-track-dinosaur-fossil/
Fossil Find Shows The Enigmatic 'Sailing Stones' Existed Even 200 Million Years Ago
https://www.sciencealert.com/there-were-sailing-stones-scudding-across-the-mud-200-million-years-ago
Excavated from Portland, Connecticut, the “Brontosaurus Footprint” has been in good condition so that even the texture of the scale on the leg of Brontosaurus can be discerned and has been treated as a museum exhibit since 1896. . Below is an image of the actual “Brontosaurus footprint”.
For this fossil, many researchers focused only on dinosaur footprints. However, a research team led by Paul E. Olsen, who belongs to the Lamont-Doherty Earth Observatory at Columbia University, pays attention to 'the trace next to the footprint'. This trace is due to 'Wandering rocks' and announced that the temperature of the Jurassic about 200 million years ago with dinosaur footprints was temporarily lowered.
According to the research team, there are two possible causes for the 'Wandering Rock'. One of them is that `` the microorganisms deposited in the mat shape slide the rocks '', but the research team said, `` If the microorganisms are accumulated in the mat shape, the footprint that can distinguish even the texture of the scales is used. I don't think it was, 'he argues,' This is unlikely. ' The remaining theory is that the water accumulated under the rocks freezes into ice, and the ice moves with the rocks that rise above it by the wind. This theory is explained in detail in the following article.
By Trey Ratcliff
However, one problem remains in this theory. That is, Portland, Connecticut, where the fossil was found, was hotter about 200 million years ago. 200 million years ago, the earth's axis is different, and it is thought that the position of Portland was closer to the equator than it is today, so it is an environment where “water freezing” necessary for wandering rocks is difficult to occur did.
The research team argued that the cause of the existence of wandering rocks about 200 million years ago may be due to the “Late Triassic volcanism” that occurred about 211.3 million years ago. The research team believes that the volcanic activity released sulfur aerosol into the atmosphere and lowered the temperature of the Earth, creating an environment where the ice necessary for the wandering rock phenomenon was created. The research team also speculates that the global temperature drop due to volcanic activity may be the cause of the mass extinction of the late Triassic dinosaurs.
Regarding the mass extinction of dinosaurs at the end of the Triassic period, there are various other theories such as `` caused by meteorite collision '', but the research team said `` the traces of wandering rocks that remain in fossils 200 million years ago Can be a clue to unravel the mystery of mass extinction at the end of the Triassic. ' The research team said, “If a rock wanders due to ice, many other wandering rocks should move in the same direction.” “A trace of another wandering rock moving in the same direction from the same area. Can be identified as the cause of the wandering rock that occurred in Portland 200 million years ago, and if it can be identified that there was ice in Portland 200 million years ago, the temperature dropped in that era Can be proof. '
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