User:AliceKXZ/sandbox

Article Edited: Triassic-Jurassic Extinction Event

EDITS to page are Underlined

Written Critique:

This article does have some strong elements, while some sections of the article need to be edited. Firstly, the article contains a general clear overview, however it is very short and needs more detail to be added. For example, the duration of the extinction needs to be added,  more information needs to be added about the species affected and more information needs to given on the differentiation between the extinction within the marine, terrestrial and plant species. Likewise, there is no information given on the poor fossil record and issues in dating the times of extinction and the time of the T-J boundaryAdditionally, there is no chronological flow to the article, it  is very scattered. For example, it only includes two sections other than the introduction, therefore more sections need to be added to better organize the article. Moreover, the wikipedia page only discusses one of the theories in depth for the extinction of Triassic period which is volcanism, but it did not explain the others possible theories in detail such as an asteroid impact, climate change, and the change in sea level.  Furthermore, the article contains only 10 citations, however they do come from good reputable sources such as Nature and Science. Additionally, when following some of the links for the citations, they cannot be found so they need to be updated. One of these citations are  the Origination, extinction, and mass depletions of marine diversity article. Likewise, one article is written in German and as such needs to be removed. Additionally, more updated articles need to be used instead of some of the dated ones. The article also includes some images which are useful and make the article more appealing, such as the image showing the ranges of families tetrapods through the Triassic and Early Jurassic. However, the image at the bottom of the article should be moved to the introduction section.  Lastly, there is no apparent bias shown in the article, which is good. Overall, this article is a good starting point when learning about the Triassic-Jurassic extinction, however much more information needs to be added about the extinction and by following the suggestions made in the critique, the article will be polished.

Edits to Introduction:

The Triassic–Jurassic extinction event which occurred approximately 201.3 million years ago,marks the boundary between the Triassic and Jurassic periods. It lasted for an estimated duration of 40,000 to 500,000 years and is one of the major extinction events of the Phanerozoic eon, which profoundly affected life on land and in the oceans.  An estimated 76% of all marine and terrestrial species and about 20 % of all taxonomic families went extinct. Additionally, in the seas, a whole class (conodonts) and 34% of marine genera disappeared.Whereas, on land, all pseudosuchians (non-dinosaurian archosaurs) other than crocodylomorphs (Sphenosuchia and Crocodyliformes), some remaining therapsids, and many of the large amphibians became extinct. Lastly, close examinations of the Triassic–Jurassic extinction event show that the extinction was much more serious at the specific/species level than at generic and family levels.

Suggested section headings:

Section title: Hypothesized Causes of Extinction

Subheadings for diff. hypotheses:

Sea level fluctuations

Significant facies changes suggest periods of regression followed by transgression in many of the classic marine Triassic Jurassic Boundary sections in Europe Marine. Therefore, regression was thought to be a possible mechanism of biotic turnover, as a decrease in available habitat and resulting competition, would be a cause for extinction. However, many of the documented regressions have no relation to the accelerated rates of extinction. In addition, it has also been previously argued that the idea of reduced habitat during regression is flawed because lowered sea level can instead create new shallow marine habitat around oceanic islands.

Bolide impact

The possibility of an asteroid impact has been suggested for a mechanism of the extinction, however no impact crater of sufficient size has been dated to coincide with the Triassic–Jurassic boundary. It was previously thought that the Manicouagan crater located in Quebec, was the cause for the late triassic extinction, although, newer research has shown that the impact melt within the crater has a date preceding the late Triassic by about 12 million years.   Additionally, the eroded Rochechouart crater in France has most recently been dated to 201 ±2 million years ago,[7] but at 25 km across (possibly up to 50 km across originally), appears to be too small to be the cause for the late triassic extinction.Moreover, there are many smaller impact sites that occur during the Triassic such as the, 40-km diameter Saint Martin structure in northwestern Canada (dated at 208 +/- 14 ma) and the 15-km Obolon structure in the Ukraine (dated as 215 +/- 25 Ma), but the size and dates of the impact sites do not directly overlap with the Triassic Jurassic Extinction.

CAMP Volcanism

Subsections on Effects of Volcanism: