Geology

metalman

metalman

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Terrane

a tectonostratigraphic terrane, is a fragment of crustal material formed on, or broken off from, one tectonic plate and accreted or "sutured" to crust lying on another plate. The crustal block or fragment preserves its own distinctive geologic history, which is different from that of the surrounding areas — hence the term "exotic" terrane. The suture zone between a terrane and the crust it attaches to is usually identifiable as a fault.





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Where is Siletzia?

Fifty million years ago, the Siletzia Terrane was a huge basaltic oceanic island, off the coast of the North American plate similar to Iceland today, but much larger. Siletzia was subducted under the North American plate, but very tiny pieces outcrop along the Pacific North West today ( the black dots below are its remaining outcrops, and evidence for its existence )

"Controversial geological theory"
the hot spot that was the source for the huge basaltic flows of Siletzia, is now known as the "Yellowstone Hot Spot"



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Uniformatism - the doctrine suggesting that Earth's geologic processes acted in the same manner and with essentially the same intensity in the past as they do in the present and that such uniformity is sufficient to account for all geologic change.

A MegaFlood is a geologic heresy




The MegaFlood animation
Rhythmites deposits show the draining of Glacial Lake Missoulia occurred 89 times, each time the ice dam breaking a lower lake level than the time before



 
@metalman

If you haven't seen it yet, you'd probably love the newest episode of the rebooted 'In Search Of' about sinkholes. You'd probably like the whole thing, but especially the last segment.
 
Why 536 was ‘the worst year to be alive’

A mysterious fog plunged Europe, the Middle East, and parts of Asia into darkness, day and night—for 18 months. "For the sun gave forth its light without brightness, like the moon, during the whole year," wrote Byzantine historian Procopius

a cataclysmic volcanic eruption spewed ash across the Northern Hemisphere early in 536. Two other massive eruptions followed, in 540 and 547.

El Salvador eruption in A.D. 536 triggered extreme global cooling

The wider geographic distribution of TBJ deposits indicates the eruption produced a much larger volume of ash and debris, which Dull now calculates at 84 cubic kilometers (20 cubic miles)


Sixth-Century Misery Tied to Not One, But Two, Volcanic Eruptions
 
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Wadi Howar: Paleoclimatic Evidence from an Extinct River System in the Southeastern Sahara .pdf

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Wadi Howar is the remnant river bed of the ancient Yellow Nile, a tributary of the Nile during the Neolithic Subpluvial from about 9500 to 4500 years ago. At that time Savanna fauna and cattle-herders occupied this region and the southern edge of the Sahara was some 500 km further north than it is today.


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Between 10,000 and 8,000 BC, the Yellow Nile connected the Ouaddai Highlands in east Chad along the border of Sudan to the Nile Valley, contributing as much as 40% of the ancient Nile river flow, Today, the river bed of the extinct Yellow Nile river are known as Wadi Howar – a valley situated in Chad and Sudan.
 
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