The End Permian Mass Extinction Essay

6177 WordsOct 19, 199925 Pages
<b>Introduction</b><br>Think of a world which existed 290 million years ago. As you look out over the terane in front of you, you think that you are on an alien planet. You see volcanoes spewing ash and lava. Beside them is the ocean which is swarming with many different species of echinoderms, bryozoans and brachiopods. As you look down onto the sea floor you are amazed at the countless number of starfish and urchins. Some animals leave you can't even describe and you have no idea even what phylum they belong to. This is a world at its height in diversity of oceanic species. Millions of wonderous species existed at this time in the ocean and most of them will never appear again in earth's history. In the geologic time scale, a million…show more content…
The concentration of Ir was at least an order of magnitude higher than the background values and this is characteristic of most Upper Permian and Lower Triassic boundaries. The scientists go on to say that "the existence of a rich Ir anomaly on a global scale within the K/T boundary layers of both marine and continental facies has been interpreted as highly impressive evidence for an impact origin. Another discovery that may serve as a marker of an event is microspherules. A variety of microsherules have been discovered in the PTB layers of the Meishan section (Xu et al., 1989). The origin of the microspherules could be multiple. They are small circular indentations in the rocks and the most abondent elements are Si or Si-Al. Mircospherules are similar to cosmic dust. Since a large amount of microspherules occurs in a thin layer of PTB layer it can serve as another event marker.<br><br>Maxwell (1989) who got his information from Clark et al. (1986) said that<br><br>The elemental in boundary clays across China suggest that there is a remote possibility that the predominantly illite boundary clay is a remote possibility that the predomonantly illite boundary clay resulted from the alteration of ejecta dust from a comet impact, but the most likely source was ash from a massive volcanic eruption.<br><br>The trace elements suggested that the dust was highly acidic and the ratios of TiO2 and AL2O3 are low enough to support the volcanic dust scenario

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