End of the Mesozoic era
The layer of iridium found all over Earth is known as the iridium anomaly. It is believed to have originated from a large asteroid impact that occurred around 66 million years ago, leading to the mass extinction of the dinosaurs. The presence of this iridium layer is one of the key pieces of evidence supporting the theory of an asteroid impact causing the mass extinction event.
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.
Stalactites are cave formations that hang from the ceiling and are formed by the dripping of mineral-rich water containing calcite. Stalactites grow downwards over time as the calcite is deposited layer by layer.
The layer below Earth's outer layer is the mantle. It is composed of solid rock that is able to flow slowly over long periods of time. The mantle is much thicker than the Earth's crust and makes up the majority of the Earth's volume.
The third layer of the Earth is the mantle. It is located beneath the Earth's crust and is composed of solid rock that is capable of flowing slowly over long periods of time. The mantle is the thickest layer of the Earth, making up about 84% of the Earth's volume.
A layer of iridium was deposited all over Earth during the Cretaceous-Paleogene (K-Pg) boundary, approximately 66 million years ago. This iridium layer is associated with the mass extinction event that led to the demise of the dinosaurs and many other species. The prevailing theory suggests that the iridium was delivered to Earth by a large asteroid impact, which created the Chicxulub crater in present-day Mexico.
The layer of iridium found all over Earth is known as the iridium anomaly. It is believed to have originated from a large asteroid impact that occurred around 66 million years ago, leading to the mass extinction of the dinosaurs. The presence of this iridium layer is one of the key pieces of evidence supporting the theory of an asteroid impact causing the mass extinction event.
Before a rock layer can be deposited, the area must undergo erosion and weathering. This breaks down existing rocks into sediment which can then be transported and deposited in a new location. The process of deposition occurs when the sediment settles into a new location and forms a layer over time.
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 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.
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.
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.
Stalactites are cave formations that hang from the ceiling and are formed by the dripping of mineral-rich water containing calcite. Stalactites grow downwards over time as the calcite is deposited layer by layer.
Ozone layer depletion is the thinning of ozone layer. It is most evident over the poles on earth.
The layer below Earth's outer layer is the mantle. It is composed of solid rock that is able to flow slowly over long periods of time. The mantle is much thicker than the Earth's crust and makes up the majority of the Earth's volume.