The End Permian Mass Extinction Essay

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IntroductionThink 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 years means
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They made a table which showed the distribution of carbon 13, iridium, and microspherules across the P/T (Permian and Triassic) border. The section was over a thickness of 35 cm. They found a sudden depletion in C-13 falling from a value near zero to a minimum of less than -6% in some samples. Similar patterns of C-13 have been observed in more than five P/T sections in China.

Some other scientists like Baud et al (1989) argue that what could have caused this anomaly is the result of a depositional hiatus or erosional disconformity. Xu and Yan argue that there is no evidence for a significant hiatus and that Baud et al. Even made a mistake in the timing of their rock layers. "If the PTB [Permian Triassic boundary] is considered a catastropic event, a short-time hiatus should be expected and is in fact a reasonable consequence of a catastrophic event" (by Xu Dao-Yi and Yan Zheng, 1993). But what is the significance of C-13 being associated with catastrophic events?

Hsu et al. (1982) said that they suggested that carbon isotope anomalies are related to microplankton productivity. We will touch again on this later in the paper. Therefore, the sudden C-13 change may indicate the exact stratigraphic position of the mass killing event at the PTB. Analysis of iridium (Xu Dao-Yi and Yan Zheng, 1993)in the layer reveild some interesting results.

High Ir

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