What element that is rare on Earth plays a key role in the KT boundary. What is an alternate theory as to how the dinosaurs became extinct?
- jpopelishLv 71 year agoFavorite Answer
Iridium is a very rare metal element
(only about 3 tons a year are mined on Earth)
that is soluble in molten iron.
Early in the Earth's history,
when the entire planet was a molten ball,
most of the iridium, on Earth,
mixed with the molten iron
and was carried with it, to the Earth's core,
because both iridium and iron
are much denser than
most of the the other minerals Earth contains,
where it remains, today.
that are understood to be parts of the metal cores
of other planetoids,
that were forming at the same time the Earth was,
but got blasted into fragments by collisions,
likewise have iridium dissolved in their iron.
So they have a lot higher concentration of iridium
than the iron depleted, crustal rocks of Earth.
Everywhere, around the globe,
there is a very thin layer of mineral deposit
that contains a much higher concentration of iridium
than the rocks of the crust, generally.
This is understood to be the dust
that fell from a huge metal meteorite, impact explosion.
There are dinosaur fossils,
in the rocks under this layer,
but none above it.
At the present, there is no competing theory
for why the dinosaurs went extinct, when they did.
In science, a theory
is the most thoroughly tested explanation, we have,
for how some part of reality works,
that has, so far, passed every test.
- SharonLv 61 year ago
the element is iridium, found in meteorites more than in Earth rocks
climate change has been suggested
- busterwasmycatLv 71 year ago
the irony is somewhat that iridium is present on earth too, but in the mantle, and that therefore a mantle-derived event could explain the iridium anomaly (it does not have to come from a primordial source out in space). The impact evidence is a lot more extensive than just the iridium anomaly so the impact explanation is pretty conclusively supported by all the evidence. The iridium anomaly was just the first indication for a very punctual event (the prior idea was that the extinction was caused by a few million years of extraordinary volcanism, so not at all a punctual event).
- VelikovskyLv 71 year ago
Would have taken less than 2 seconds to find it online.
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- 1 year ago
The element iridium plays a key role in the KT boundary that is displayed in the geologic strata in several locations around the earth, and which marks the demise of the non-avian dinosaurs.
Iridium is a very heavy element and most of it ended up in the earth's core during the formation of the earth 4.5 billion years ago. As a result, iridium is very rare elsewhere in the earth. It is, however, relatively common in meteorites.
All of the evidence indicates that the KT boundary, because it contains a significant amount of iridium, is the result of a massive asteroid impact on the earth 66 million years ago, and that is what led to the extinction of the non-avian dinosaurs. That was determined several decades ago and has been verified by several other findings, including the crater that resulted from the impact just off the Yucatan Peninsula.
The link in Source below provides an article about an amazing recent find of fossils displaying evidence of what appears to be the direct result of that asteroid impact.
There is NO alternate SCIENTIFIC theory as to how the dinosaurs became extinct.
What creationist pseudo-scientists say is that the dinosaurs died out shortly after the (mythical) biblical flood, and the fossil record is a result of that flood. However, that claim has absolutely NO evidence for it whatsoever and is flat-out contradicted by the actual nature of the fossil record.
There is NO way that mythical flood could have formed the thousands of geological strata--which were formed by several different processes,not all of them a result of water--in which fossils are found.
But most significantly, you will not find, for example, ANY fossils of ANY of the 5,000 present-day species of mammals, INCLUDING HUMAN, in the same strata in which dinosaur fossils are found ANYWHERE in the world. The only mammal fossils that are found in the same strata with dinosaur fossils are of relatively small early types having no clear relationship with any of the present-day species.
That is flat out contrary to creationist claims that humans and dinosaurs co-existed.
The fact is that mammals did not come into their own and eventually evolve into the present-day species until long after the demise of the non-avian dinosaurs.
That includes humans. The fossil record is clear in showing that humans evolved from a common ancestor with the apes over a period of of around 6 million years, with modern-type humans arising around 300,000 years ago.
- CarolOklaLv 71 year ago
Iridium. A particular isotope of iridium.
I suppose an alternate theory is they all died in world wide flood that never happened .much later, but there is NO physical evidence for world wide flood at the SAME TIME. The regional floods were at DIFFERENT times, and there is physical evidence for those regional floods.
- CRRLv 71 year ago
Iridium. One interpretation is that thos is a result of a giant meteor impact but an alternative is that this comes from a high level of volcanic activity associated with Noah's Flood. It's quite common for dinosaur fossils to show signs that the dino drowned or was buried rapidly in sediment.
Following the flood dinosaurs from the Ark apparently had trouble adapting to the new environment and became extinct.
- PhotonXLv 71 year ago
<What element that is rare on Earth plays a key role in the KT boundary?> I'm pretty sure you could have found iridium mentioned in many articles had you simply looked. In fact, simply googling "KT element" points to "Iridium Anomaly" right at the top of the link page. https://www.google.com/search?ei=WxfRXJO_E4eN0wKmp...
<What is an alternate theory as to how the dinosaurs became extinct?> And I imagine, had you devoted any thought to it, you would have thought of volcanoes on your own. Likewise, searching for "dinosaur extinction alternative theory" points to that.
You have a global electronic information network right at your fingertips, something unimaginable when I was your age. I'm baffled that you don't utilize it.