At https://sciencenorway.no/geology-meteorites/when-a-several-hundred-metre… … a crater at the bottom of the Barents Sea is 40 km in width. It is located between Svalbard and northern Norway and was churned out by a 1.6 km diameter meteor, it has been estimated. It took place around 142 million years ago on the geological column. A giant wave engulfed Norway and Greenland. The actual extent of the North Atlantic at this time is not mentioned but Greenland would have been a good deal closer than it is now. The article seems to assume a sea existed at this point, in spite of Pangaea. Perhaps it was at the top of Pangaea. It has been dubbed the Mjoinir crater. It is well preserved and currently 350 m below the surface. It also created a massive fire, even on the sea floor, as oil in the bedrock was set alight. Unfortunately, there is no surviving piece of the said meteorite. To explain this we are told it evaporated in the explosion. Mjoinir, in mythology, was the hammer of Thor = 'the one who crushes the dust.' The blast is said to have created a huge water column that may have been a kilometre in height. However, Mjoinir did not create an extinction event [which should place a question mark around the date chosen for its manifestation] – or even affect the environment, very much [apart from some dead fish]. The tidal wave was so big it washed over the land as far as Russia. It also coincided with a massive algae bloom. Now, where have we heard that before? Yes, in the Cretaceous = the chalk formations. The Cretaceous is dated 145 to 66 million years ago – although these exact dates have varied in time and source. On that basis the meteorite is very close to the end of Jurassic. Was there not an extinction event at this time? It seems the Jurassic-Cretaceous was originally associated with an extinction event but has subsequently been downgraded. The article reflects this move by geologists. However, one might consider the whole of the Cretaceous as evidence of that extinction event – as it is mainly known via sediments. There are of course problems in condensing so much of geological history and the Cretaceous chalk, for example, is usually divided into three episodes of formation. Some untangling is required, from a catastrophic laying down angle. One should avoid over simplification. There exists distinct evidence of the passage of time, for example, such as the existence of burrows made by marine creatures on the floor of the three divisions.
At https://sciencenorway.no/geology/the-famous-jutulhogget-canyon-was-crete… … here we have another megaflood, creating a huge canyon in south central Norway known as the Jutulhogget, between the Rendalen and Osterdalen valleys. In mythology, it was formed by the troll Rendaljutulen. However, geologists now discount the troll and say it was a megaflood that created the landform. Several hundred thousand cubic metres of water per second excavated the canyon – at the end of the Ice Age. One may note here that is how it starts but progresses to place the megaflood at the beginning of the Holocene, somewhat later on the geological column and post dating even the Younger Dryas episode. Or does it. Whatever, the event involved a lot of meltwater first becoming blocked up in a huge lake as the ice sheet back tracked, and then the lake breaching to release an awful lot of water as if somebody had upended a saucer full of milk by tilting it. The breach was made after a long period of time as there is a prominent strandline in one of the images at the site, denoting the former lake level. This rules out any connection with the end of the Late Glacial Maximum as that event would have led to the formation of the lake. It's location also rules out a flood of water with an origin in the ocean as the canyon is inland and runs south towards Oslo. Geologists are now saying the flood peaked at 1 to 1.5 million cubic metres per second. The rock walls on either side of the canyon are extremely steep, as water has carved out a channel into a sandstone formation which is described as brittle. A lot mud and silt from the lake bottom was also dislodged, forming a layer of sediment further south in the journey of water. . Basically, the water cascaded down the course of what is now the Glomma River, carving out the canyon between what are now two valleys but were presumably a single valley [which may have originally been formed by a glacier during the Ice Age]. The comparison might be made with the scabland megaflood in North America, which occurred at about the same time.