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End of the Mesozoic era
High concentrations of iridium appears in a layer called the K-T boundary which corresponds to the time of the extinction of non-avian dinosaurs. Iridium is a metal that is rare on earth but common on many bodies in outer space such as asteroids. It is believed that an asteroid collided with earth 65.5 million years ago, setting in motion events that would cause a mass extinction, spreading a layer of iridum in the process.
Tectonic plates are part of the Earth's crust known as the lithosphere. They slide over the outer part of the Earth's mantle called the asthenosphere.
What observations did you make as to how ice deposited sediments over time
The upper part of the mantle called the asthenosphere is the layer on which the earth's lithosphere (crust plus uppermost rigid mantle) rides.This soft layer serves as support for the crust to float and move over time due to its partial suspension.
End of the Mesozoic era
High concentrations of iridium appears in a layer called the K-T boundary which corresponds to the time of the extinction of non-avian dinosaurs. Iridium is a metal that is rare on earth but common on many bodies in outer space such as asteroids. It is believed that an asteroid collided with earth 65.5 million years ago, setting in motion events that would cause a mass extinction, spreading a layer of iridum in the process.
The ozone layer is spread all over. It is over the whole earth.
The study of the layers of the Earth that have been deposited over a long period of time is called stratigraphy. This field helps scientists understand the chronological order of rock layers and their composition, providing insight into the Earth's past environments and geologic history. Stratigraphy is crucial for interpreting the history of life on Earth and understanding past climate changes.
Ozone layer is formed all over the earth. It is there in stratospheric layer.
Ozone layer protects us from the UV rays. These rays are harmful for life on earth.
The original observation was that in the fossil records there is a layer with high levels of iridium and osmium at the time of dinosaur extinction. Iridium and osmium are common is asteroids. For the layer to be all over the globe it must have been a major strike which would have caused global wide climate change causing a mass extinction.
The ozone layer surrounding earth is being depleted. It is due to the use of CFC's.
Ozone layer is a protective layer over the earth. It protects us from the UV rays of the sun.
Iridium is a very rare element in Earth's crust, however rocks that have an age equal to that of the K-T boundary are significantly enriched in iridium. It is theorised that this enrichment is due to the impact of an asteroid with Earth (as asteroids are rich in iridium and the resultant massive explosion spread iridium enriched debris all over the world). This asteroid impact is thought to have been a significant event in the mass extinction even that wiped out the dinosaurs. This is known as the Alverez hypothesis. For more information, please see the related link.
Ozone layer depletion is the thinning of ozone layer. It is most evident over the poles on earth.
First, a layer of clay that would turn to shale was deposited. Next, a layer of plant life that would become coal was deposited, then another layer of clay. Over time, the clay became shale, and the plants became coal. Sort of like how did the blanket on your bed get between the sheets and the bedspread? You put on the sheets, then the blanket, then the bedspread.