Source

Part 1: Description of the 100,000-Year Orbital Cycle

Part 2: Description of the 40,000-Year Obliquity Cycle

Part 3: Implications of the 40,000-Year Obliquity Cycle

26,000-Year Axial Precession Cycle

In addition to the 40,000-Year Obliquity Cycle, is the 26,000-Year Precession Cycle.

As Earth rotates, it wobbles slightly upon its axis, like a slightly off-center spinning toy top. This wobble is due to tidal forces caused by the gravitational influences of the Sun and Moon that cause Earth to bulge at the equator, affecting its rotation. The trend in the direction of this wobble relative to the fixed positions of stars is known as axial precession. The cycle of axial precession spans about 25,771.5 years.
Source

I have my own thoughts on the subject that I detailed in an article (What is an LLSVP?) on Large low-shear-velocity provinces (LLSVP).

The LLSVPs reacting with the Dzhanibekov Effect (see video below) change the rotation of the Earth.

If Earth had a straightforward center of gravity we would see it flip in rotation like a tennis racket when flipped. Because of our multiple axis points, we would see a wobble. My personal conjecture is that this process is not a continuous movement but a series of jerks precipitated by Dansgaard–Oeschger events.

In the Northern Hemisphere, they take the form of rapid warming episodes, typically in a matter of decades, each followed by gradual cooling over a longer period.

Leland_McInnes

Melting polar ice nudges the rotation so it arrives at a new equilibrium with regard to the LLSVPs. Following the highs of the Dansaard-Oeschger Events are Heinrich Events.

Goeland1234

During the Holocene (since the last glaciation) the cold cycle is referred to as Bond Events.

Bond Events

You will notice that there is roughly a 1400-year cycle to Bond Events except between ≈ 3900 BC and ≈ 6200 BC and the inclusion of the Little Ice Age. The first exception may be as simple that they just haven't found evidence at the right layer, around 4800 BC. It is interesting that the Assyrian calendar places this around Year 1.

The modern Assyrian calendar, however, uses a different reckoning: 4750 BC was set as its first year in the 1950s,[2] based on a series of articles published in the Assyrian nationalist magazine Gilgamesh; the first came in 1952 and written by Nimrod Simono and dealt with the Akitu festival, then an article by Jean Alkhas in 1955 (April, issue 34) fixed the year 4750 BC as the starting point.[3] Alkhas referenced his information to a French archaeologist, whom he did not name, as stating that a cuneiform tablet dating to 4750 BC mentioned the year of the calming of the great flood and beginning of life.
Source

I don't want to go biblical here but it is possible this follows the "Noah's Flood" event or possibly some undocumented event like the flooding of Doggerland 1400 years earlier.

The second exception to the pattern was the Little Ice Age. If it is unrelated, this suggest that the next bond event should be roughly 1400 years after ≈ 600 AD (Late_Antique_Little_Ice_Age). If this is true, perhaps we are due for another slippage in the wobble.

The following are 10% beneficiaries for their ongoing support:

@tarpan
@zero-to-infinity
@steem.skillshare
@digital.mine
@steemchiller