Climate Clues

10 May 2021

At ... a 50,000 year history of changes in the Atlantic Meridional Overturning Circulation [AMOC] has been achieved via sediment cores taken off the coast of western France. The record is said to show the current moved fster during warmer periods and languished during colder phases of the Late Pleistocene. However, it was already well known that climate fluctuated as a result of cooling Heinrich events and warming Dansgaard Oeschger events, which seem to follow a regular cycle. The research appears to be aimed at proving the behaviour of AMOC was responsible for these ups and downs. Whilst this is not impossible there is also another way of looking at the evidence produced from the sediment cores. The shifts in AMOC could be as a result of plunging temperatures or warming weather, responding to climate change rather than initiating climate change. For example, if warming occurred, for unknown reasons, AMOC could have responded by becoming more active, and in the reverse situation, during a Heinrich event, AMOC would be compromised - failing to get into the northern section of the North Atlantic. Merely pointing a finger at AMOC as the base line responsible for these climate changes supposes that ocean currents can  change of their own volition rather than from other factors, such as low solar activity or a loaded atmosphere. Scientists like to compartmentalise - put things in a box, or shove it out of sight [and any query is subsequently met with the perceived orthodox view] without the need to explore the issue any further - until a maverick comes along. Museums are full of boxes and drawers in which artifacts are placed - and there are far more behind the scenes than on  display. If they are able to compartmentalise the Heinrich and Dansgaard-Oeschger events as due to the switching on and off of AMOC they could forget all about it. The fact is this is an interesting series of climatic ups and downs that requires more research - not put in a box and ignored. Another problem is that astronomical factors may drive the cycles and this would not see the light of day. It is quite dark in a box or drawer. Leaving the question open would allow other minds to deliberate and experiment and provide alternative views.

At ... this is a fascinating piece of research by a group of geologists who think they might have found fragments of an ancient ocean floor in the Baltimore locale. We are told a geological upheaval millions of years ago involved a collision of tectonic plates that thrust fragments of an ocean floor from a long vanished ocean, up towards today's surface rocks. The evidence was unearthed from a quarry and various other holes in the ground as a result of construction work etc. The upheaval in question occurred along the Appalachian Mountains to as far north as Newfoundland and then on the opposite side of the Atlantic, in Scotland. Presumably the upheaval was due to the formation of the Atlantic - which widened over the following millions of years to its present situation. Wherefore the ancient ocean. Presumably this was even more ancient than Pangaea. This accounts for bits of the old ocean rather than a substantial layer of rock. The fragments are found within more modern rocks - or rocks formed during the upheaval.

Basically, geologist have found that outcrops in the area contain ophiliote fragments - said to be parts of ancient ocean floor. They add that at the same time, they are rocks that may have an origin in the Mantle - and they may have been propelled into the continental land mass. This sounds somewhat interesting if the upheaval involved a lot of upwelling from deep in the crust - including an infusion of water. Where did the water that became the Atlantic come from. Internally, is one possibility - and of course a rearrangement of earth's oceans is another possibility. The rocks in question are known as the Baltimore Mafic Complex and a little research on them might be worth while. These intermittent outcroppings go back to the formation of the Appalachian Mountains. So how did oceanic crust get crunched up and then mixed up with rock laid down during that upheaval?