During the last Ice Age, presumably the Late Glacial Maximum, massive ice bergs calved from the northern ice sheet and caused the weather in North America to change, by the action of discharging meltwater into the Atlantic. It is thought. How much is fact and how much assumption is difficult to say. These periodic episodes are known as Heinrich Events and have a vague similarity to the Dryas events of the early Holocene. There is a considerable literature on the subject which is easy to access. See https://phys.org/news/2023-04-massive-iceberg-discharges-ice-age.html … but I won’t dwell on any of that as simply looking at the Wiki will provide a generalised overview. What is intriguing is the following – and puzzling the researchers. We are told they occurred over a long period, between 60,000 and 16,000 years ago – which is the LGM plus another 20,000 years or so. What causes them is an unknown – but there are a lot of theories, including the consensus view as expressed in this article. One may note the 16,000 years ago date embraces the Oldest Dryas episode – which is alternatively known as Heinrich One. It is a fascinating subject but as always, catastrophism is not part of the debate. It is a consensus view that tipping lots of cold water into the North Atlantic alters the global ocean circulation system. This is essentially a theory as it is known that El Nino events can alter the same conveyor belt, its alternative name. It makes sense that cold water can do something similar to warm water, but one is near the surface and the other is deeper. Whether there actually was an outpouring of cold water, from the ice sheets or from the melt water lakes that formed at the end of the Ice Age, is one you accept, or question. As in all such things it is best to read the full article if you want to get your head around the detail – go to https://www.nature.com/articles/s41586-023-05875-2 … and the argument made is that Heinrich events did not effect Greenland. This is the big surprise. The temperature stayed the same. It did not go up or down. Having said that, Greenland temperatures were generally somewhat lower than they are in the Holocene. This appears to be quite different to what was going on at the South Pole. Or at least, at the West Antarctic Peninsular.
Our findings raise questions, they go on to say. The ice core used came from the highest point on Greenland, where the ice sheet is currently 2 miles thick. This the point where catastrophism may kick in because if the LGM ice sheet, located mainly in NE North America and NW Europe, had its apex somewhere off the coast of western Greenland we might not expect there to have been any melting of the ice – as it was too close to the North Pole. What they need to establish is where the Heinrich ice melt was occurring – if not on Greenland [or at least, NW Greenland]. What are these findings really telling us? At the least it is raising a question mark about the nature of Heinrich events, and what might have stimulated them, or brought them to a close. The situation at the South Pole could also be explained by a small movement at the poles as SE Australia was cold but the West Antarctic peninsular not as cold as it is in the modern world. What might cause a pole shift? One would have to look at electro-magnetic processes, and changes associated with magnetic reversals and realignment of the dipole.
The next story comes from the Pacific region and another anomaly, an underwater plateau – see https://phys.org/news/2023-06-massive-underwater-plateau-solomon-islands.html … and although it is covered in sediment and its basalt base represents the floor of the Pacific, somewhat higher than the surrounding sea floor, there is no indication that it ever protruded above the ocean surface. It was published in the journal Science – see https://doi.org/10.1126/science.ade8666 … and again, it would be more informative to read a fuller version of the article. The Ontong Java Plateau was formed by volcanic/ tectonic processes, with the basalt seeping out of the interior of the earth. It therefore has some affinities with the Deccan Traps in India and a similar land based volcanic outpouring in Siberia. The Deccan Traps may have been activated by the dinosaur killing asteroid but one should not assume a similar process for the outpouring of magma. Britannica has an interesting post on the period between 120 and 80 million years ago. The outward motion of the Pacific flow resulted in crustal accretion and arc magmatism along the western continental margin. At the same time Canada and Alaska appear to have moved northwards. One might explain that by an expanding earth – or by plate tectonics [the preferred mainstream theory]. It has generally been thought that the magma eruption occurred at the same time as a black shale was laid down in various parts of the world – indicating some kind of global event. The shale is thought to represent a period of depleted oxygen in the earth system. The article, above, claims this connection does not exist as they have dated the eruption at 110 million years ago, 10 million years after the shale deposit. This is of course mucking about with uniformitarian numbers which are basically meaningless if sediments during catastrophic events were laid down quickly, as they are during major vocanic events in the modern world. It could be argued as nit picking – using the geochronology column to pretend you were at the pinnacle of science. One stepp ahead of earlier geologists.
However, the Ontong Java Plateau is part of a bigger magma outpouring, as the Britannica indicates. This includes the Manihiki Plateau and the Hikurang Plateau. Cores were drilled into sediment and the basal basement and they also used a new method to arrive at a slightly different date. In reality, whatever occurred may have happened very quickly, over what uniformitarians say took millions of years.