geological-time

Falling In

Yesterday my sister brought an animated short film to my attention:

The Ballad of Holland House

Watch it. It’s amazing. It’s gorgeous, moving, and connects with me for a lot of reasons. It’s always been difficult to explain that I’ve used erosion as plot. People who haven’t grown up on the shore don’t really get to see its effects in their daily lives. Rest assured, erosion is plot.

There’s also something haunting about houses being swallowed up by the sea; it’s tied to the idea of erasure, and the understanding that one house or one life is barely a speck in geological time. That same idea can be quite hopeful: there’s freedom in knowing that nothing we make or do is permanent. And so, yes, following the course erosion can definitely be plot.

A few disappearing and vanished towns:

Dunwich

South Cape May

Cedar Island

Washaway Beach, WA. (with video)

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Mat Brown
Deep History, Illustrated  
[images on Flickr]
Artist’s website / store  |  Artist’s work in other series

Hadean
The first geologic eon began with the formation of the Earth about 4,600 million years ago and ended 4,000 million years ago.

Thermal Genesis   
More broadly: abiogenesis - the natural process by which life arises from simple organic compounds. The earliest life on Earth existed at least 3,500 million years ago, at the beginning of the Archean Eon when sufficient crust had solidified following the molten Hadean Eon

Cambrian
First geologic period of the Paleozoic Era, lasting from 541 to 485 million years ago.   Although complex, multicellular organisms gradually became more common in the millions of years immediately preceding the Cambrian, it was during the Cambrian that life exploded, rapidly diversifying and producing the first representatives of many modern phyla,  However, while diverse life forms prospered in the oceans, the land was comparatively barren.

Devonian
A geologic period of the Paleozoic Era that occurred from 419 to 358 million years ago. This was the first significant adaptive radiation of terrestrial life.

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Sea scorpions, or eurypterids, were the largest arthropods the world has ever seen.

Jaekelopterus rhenaniae

8.2 feet (2.5 meters) long

18-inch (46-centimeter) spiked claw

They had a pair of pincers, and in some species these too could become very large. Sea scorpions were predators that were in their heyday in the Silurian and Devonian, though they survived into the Permian.


it’s fine.  This is normal.

Was Our Planet Really Once a Hell on Earth?

For the first 500 million years of its existence, our planet was believed to literally be a hell on Earth. But new research shows that this early Earth may have been surprisingly similar to the present day, complete with oceans, continents and active crustal plates.

This alternate view of Earth’s first geologic eon, called the Hadean, is based on a comparison of zircon crystals formed four billion years ago with those formed during the same time period in Iceland. This icy country is supposedly what early Earth geological conditions were like, and so serves as a sort of blueprint for scientists studying the beginnings of our planet.

"We reasoned that the only concrete evidence for what the Hadean was like came from the only known survivors: zircon crystals — and yet no one had investigated Icelandic zircon to compare their telltale compositions to those that are more than 4 billion years old, or with zircon from other modern environments," lead researcher Calvin Miller of Vanderbilt University said in a statement.

Until 30 years ago, scientists thought the Hadean period was hellishly hot, and Earth was covered by a giant “magma ocean.” This view was based on the fact that they could never find rock formations from that time period, jumping to the conclusion that the intense heat melted the rocks, leaving behind no trace.

But then geologists discovered zircon crystals - a mineral typically associated with granite - preserved in younger sandstones. Radiometric dating and other analytical techniques allowed the researchers to study early Earth’s crust via these four-billion-year-old crystals, as well as extract information about the environment in which the crystals formed, including the temperature and whether water was present.

And after comparing these crystals with about 1,000 ancient zircons sifted from volcano and sand samples off Iceland, the researchers found that Icelandic zircons grew from much hotter magmas than Hadean zircons.

Despite the assumption that Earth was insanely hot, their analysis revealed that at some points during the Hadean period Earth’s crust cooled enough so that surface water could form - possibly on the scale of oceans.

"Our conclusion is counterintuitive," said Miller. "Hadean zircons grew from magmas rather similar to those formed in modern subduction zones, but apparently even ‘cooler’ and ‘wetter’ than those being produced today."

The findings were published in the journal Earth and Planetary Science Letters.

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Major Units of Geological Time
Definitive Events in Biological and Geophysical History

The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga (billion years ago).

Other subdivisions reflect the evolution of life:
    the Archean and Proterozoic are both eons,
    the Palaeozoic, Mesozoic and Cenozoic are eras
        of the Phanerozoic eon.

The two million year Quaternary period, the time of recognizable humans, is too small to be visible at this scale.

(via Wikipedia)

Some people say that depicting geologic time and evolutionary history using a clock face design trivializes the truly incomprehensible time frame being depicted, and so is misleading.  

The time involved is in fact something very hard to get your mind around, but doesn’t that make any depiction, even on a really long linear time line, misleading?  Probably.

SCP-1859: Life Over Geological Time

SCP-1859 is a rapidly developing ecosystem enclosed by a temporal anomaly, located in a chamber, ███ km in diameter. The chamber is located at [DATA REDACTED], approximately █ km below the surface, initially believed to have been a natural nuclear fission reactor due to relatively high amounts of emitted radiation. It is currently unknown how the chamber is able to remain stable despite its size, or why the chamber is cooler than the surrounding mantle, however it is hypothesized that this is related to the temporal anomaly in some way.

Initial observations of SCP-1859 noted unusually high levels of incredibly energetic ionizing radiation, with both wavelength and flux decreasing as one travels away from the centre of the chamber. When researchers looked into the centre of SCP-1859, they observed it as appearing incredibly hazy and distorted. It was soon discovered that both of these observations were related to the above mentioned time anomaly. As one approaches the centre of the chamber, time is observed to pass at a different rate, such that an observer farther from the centre sees external time pass more quickly than an observer closer in.

The relationship between time and the distance from centre is such that radiation that enters the anomaly is red-shifted so that, when it is reflected from an object within, it is scattered in a manner consistent with a much lower frequency wave. Likewise, radiation produced in the centre of the anomaly, no matter how low its energy, is blue-shifted to such an extent that the end result, when observed from outside, appears as high energy ionizing radiation. Though the actual source is unknown, calculations indicate that, at the centre, the photons are consistent with the primary resonance frequency of electromagnetic radiation in the chamber itself (approximately ███ Hz, at a rate of [REDACTED]). Despite the rate of photon production being very low, the compression of time ultimately results in lethal doses of ionizing radiation at certain distances.

The innermost Green Zone (initially labeled the Black Zone) is a region in which flux and frequency of radiation are such that life can theoretically be sustained. The Red Zone is where the radiation is blue-shifted to potentially dangerous frequencies and the flux is high enough that lethal exposure is guaranteed. Radiation in the outermost White Zone, though more energetic, is sufficiently diffused that radiation poisoning can be treated, so long as exposure is limited.

Additional information, as well as a summary of the natural history and ecology of SCP-1859 can be found in the primary document here.

The geological timescale: Yanks VS Brits

The geological timescale is broken down into geochronologic segments, time periods based upon the continuity of rock strata and the relative time relationship between these strata. But what concerns us today is – where did the names of these time periods come from and who named more? Brits or Yanks?

Keep reading

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A New “Golden Spike” Monument in Colorado Marks Geologic Time 
Andrew Alden [source] | October 31, 2013

For something that is supposed to keep track of 4 billion years of history, the geologic time scale is quite a fuzzy and slippery yardstick. After two centuries of careful research and argumentation, the world’s geologists have only recently adopted a system to literally nail down the different time periods taught in geology school.

Last week that project took another slow step forward as a “golden spike” was officially driven into a precise spot on the ground near Pueblo, Colorado, a benchmark for the beginning of the Turonian Age.

The Turonian is, in the ICS’ geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma (million years ago).   [Wikipedia]

The Western Interior Seaway then divided North America into eastern and western halves; Appalachia and Laramidia.

24 million years after the Turonian ended, a massive asteroid struck the Yucatan, spelling the end for the dinosaurs.

Continue reading

IMAGES
[1] Photo courtesy Brad Sageman 
[2] Ichthyornis by S.V.Naugolnyh 
[3] Cover to American Journal of Botany, 89(12), 2002, showing leaf and pinecone litter on a Turonian Coastal Plain forest floor with the oldest unequivocal fossil monocot
[4] Zuniceratops by cheungchungtat
[5] The Turonian Stratotype Section near Pueblo, Colorado. Photos courtesy Bob Kay
[6] J of Sedimentary Research [X]  
[7] Chronostratigraphic chart