On 5/7/2024 11:11 AM, erik simpson wrote:
Near-collapse of the geomagnetic field may have contributed to
atmospheric oxygenation and animal radiation in the Ediacaran Period
https://www.nature.com/articles/s43247-024-01360-4. (open access)
Abstract
Earth’s magnetic field was in a highly unusual state when macroscopic animals of the Ediacara Fauna diversified and thrived. Any connection
between these events is tantalizing but unclear. Here, we present single crystal paleointensity data from 2054 and 591 Ma pyroxenites and gabbros
that define a dramatic intensity decline, from a strong Proterozoic
field like that of today, to an Ediacaran value 30 times weaker. The
latter is the weakest time-averaged value known to date and together
with other robust paleointensity estimates indicate that Ediacaran
ultra-low field strengths lasted for at least 26 million years. This
interval of ultra-weak magnetic fields overlaps temporally with
atmospheric and oceanic oxygenation inferred from numerous geochemical proxies. This concurrence raises the question of whether enhanced H ion
loss in a reduced magnetic field contributed to the oxygenation,
ultimately allowing diversification of macroscopic and mobile animals of
the Ediacara Fauna.
Note the "may have" of the title. Coincidences may or may not be
telling us something, but it's an intriguing idea.
Creationists should note that this is Ediacaran diversification and not Cambrian. Just another bit of Earth's history not mentioned in the Bible.
This also would have increased mutation rate of life on earth. Cosmic
rays are supposed to penetrate around 25 feet into the earth's crust. I
don't know how much water that is equivalent to. When they pass through
a lifeform they cause multiple ionizing events in each cell, so my guess
is that this increased the rate of structural evolution of the genomes
of the lifeforms in existence.
The claim is that surface lifeforms could die out if we lost our
magnetic field, but at this time it probably only baked the lifeforms in shallow water. From what I have seen on the subject, the magnetic field diverts most of the cosmic radiation that would have hit the earth.
Ron Okimoto
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