User:Iborche/sandbox

Article Draft

The Juan de Fuca Ridge is a mid-ocean spreading center and divergent plate boundary located off the coast of the Pacific Northwest region of North America. The ridge separates the Pacific Plate to the west and the Juan de Fuca Plate to the east. It runs generally northward, with a length of approximately 500 kilometers (300 miles). The ridge is a section of what remains from the larger Pacific-Farallon Ridge which used to be the primary spreading center of this region, driving the Farallon plate underneath the North American plate. Today, the Juan de Fuca Ridge pushes the Juan de Fuca Plate underneath the North American plate, forming the Cascadia Subduction Zone.

Discovery

The first indications of a submarine ridge off the coast of the Pacific Northwest was discovered by the USS Tuscarora, a United States Navy sloop under the command of George Belknap, in 1874. Surveying a route for an undersea cable between the United States and Japan, the USS Tuscarora discovered a submarine mountain range approximately 200 miles from Cape Flattery, which they did not consider a major discovery because throughout their voyage they found other locations with a larger profile, making the ridge seem insignificant in comparison.

Geologic History

Age of oceanic crust surrounding the ridge, as indicated by magnetic anomalies in the physical structure of the rock as they cooled, permanently recording the earth's magnetic field at the time

The ridge was at one point a part of the larger Pacific-Farallon ridge system. Approximately 30 million years ago, the Farallon Plate, being driven outwards by the Pacific-Farallon ridge, was pushed underneath the North American Plate, splitting what remained into the Juan de Fuca Plate to the North and the Cocos Plate and Nazca Plate to the South.

Morphology and Segmentation

The Juan de Fuca ridge is not one continuous ridge, it is comprised of seven main ridge segments. From north to south these segments include the West Valley, Endeavour, Cobb, CoAxial, Axial, Vance, and Cleft ridge segments.

Composition

sections

Notable Features

Node locations of the OOI cabled observatory network

The Axial Seamount is a submarine volcano located on the ridge at a depth of 1400m below sea level, rising 700m above the average of the rest of the ridge. Axial is the most active volcano in the Pacific northeast, and an underwater cabled observatory has been installed there as a part of the National Science Foundation's Ocean Observatory Initiative, making it one of the best studied volcanoes along mid-ocean ridges.

The Endeavour segment in the northern end of the ridge is another active and highly studied region. Sharp chemical and thermal contrasts, high levels of seismic activity, dense biological communities, and unique hydrothermal system all make the segment a primary focus of research.

Some of the most intense and most active Hydrothermal vents are located along the Endeavour segment, with more than 800 individual known chimneys within the ridge's central region, and a total of five major hydrothermal fields along the ridge. These chimneys release large amounts of Sulphur rich minerals into the water, which allow bacteria to oxidize organic compounds and metabolize Anaerobically. This allows for a diverse ecosystem of organisms to exist in the low oxygen conditions near the seafloor around the ridge.

Eruptions and Earthquakes

The first documented eruption took place on the Cleft segment in 1986 and 1987. Hydrothermal megaplumes indicated a large rifting event, releasing hydrothermal fluids as a result of lavas being extruded from a dike. A majority of the eruptions along the ridge are dike injection events, where molten rock is extruded between cracks in the crust's sheeted dike layer. Typically eruptive events can be predicted, as they are preceded by large earthquake swarms in the region.

A significant event took place in June of 1993, lasting 24 days at the CoAxial segment. Cruises deployed as a result of the eruption sampled event plumes, cooling lava flows, and discovered microbial communities living on the seafloor around the ridge.

In February of 1996, an event consisting of 4,093 earthquakes, lasting 34 days was recorded at the Axial Volcano, yielding similar scientific results to the 1993 eruption.

In January of 1998 an event consisting of 8,247 earthquakes lasted 11 days at the Axial Seamount. Lava was released from the caldera of the volcano, flowing down the southern side of the mountain, creating a sheet flow over 3km long and 800m wide. This was the first time an underwater eruption had been monitored in-situ in real-time.

In June of 1999, 1,863 earthquakes were recorded over 5 days, and a hydrothermal temperature increase was observed at the Main Endeavour segment.

In September 2001, 14,215 earthquakes were detected over a 25 day period in the Middle Valley segment.

Researchers at Oregon State University suggested the Axial Seamount had an eruption interval of approximately 16 years, which would place the next major Axial eruption in 2014. In 2011, during a dive on the seamount, new lava flows were discovered and some instruments had been buried in lava flows, indicating the volcano had erupted since the last expedition to the ridge. This is considered the first successful forecast of a seamount eruption. The caldera floor dropped by more than 2 meters after the eruption, and the rate at which it inflates as Axial's magma chamber refills can be used to once again predict the next eruption.

Tectonic Activity

The ridge is a medium rate spreading center, moving outwards at a rate of approximately 6 centimeters per year. Tectonic activity along the ridge is monitored primarily with the U.S. Navy's Sound Surveillance System (SOSUS) array of hydrophones, allowing for real time detection of earthquakes and eruptive events.

The Juan de Fuca Plate is being pushed east underneath the North American Plate, forming what is known as the Cascadia subduction zone off the coast of the Pacific Northwest. The plate does not subduct smoothly and can become 'locked' with the North American plate. When this happens, pressure builds up until the contact suddenly slips, triggering massive earthquakes up to or greater than magnitude 9. Major earthquakes along this zone occur on average every 550 years and can have major impacts on the physical structure of the North American continent and seafloor.

Prior weeks, not directly related to article draft

Finding Sources Week 4

I agree with William that this topic could potentially get out of hand since there is so much available information. I think it will help if you focus down on specific questions related to the topics you've listed or consider some of the concrete questions that William has given you. Erik (talk) 13:36, 24 April 2017 (UTC)

A good start. The challenge with this topic is that there will be "too many" sources since this is a very heavily studied feature compared with for example the Gorda Ridge. Questions to consider not in your list. Basic facts such as location, length, spreading rate and morphology, segments, primary features (e.g., Axial Seamount, Endeavour ridge). History - Part of former Farallon-Pacific Ridge. Tectonics. hydroacoustic monitoring Megaplumes (linked to hydrothermal vent plumes). Cabled observatories to Endeavour and Axial. There are two good Oceanography Magazine articles http://tos.org/oceanography/article/endeavour-segment-of-the-juan-de-fuca-ridge-one-of-the-most-remarkable-plac http://tos.org/oceanography/article/hydroacoustic-monitoring-of-oceanic-spreading-centers-past-present-and-futu Also lots of stuff from a google search that is not peer reviewed. It is worth using Georef for a focused search for peer reviewed articles. William Wilcock (talk) 04:56, 24 April 2017 (UTC)

I have selected the Juan de Fuca Ridge page to work on. Some topics I've brainstormed which may be appropriate to add include volcanism along the ridge, hydrothermal vent activity, the physical structure of the ridge, microbial life and other extremophiles in the extreme environment near the ridge, and I'm certain many more possible topics are also appropriate. This page seems very empty and no one has yet added to the talk page to discuss additions or improvements to the page.

Some sources which may be helpful:

- Faulting and hydration of the Juan de Fuca Plate system (physical properties)

- The importance of hydrothermal venting to water-column secondary production in the northeast Pacific (biological systems)

- Assessing the influence of physical, geochemical and biological factors on anaerobic microbial primary productivity within hydrothermal vent chimneys (biological systems)

- Rift topography linked to magmatism at the intermediate spreading Juan de Fuca Ridge (physical structure)

- Sedimentation, stratigraphy and physical properties of sediment on the Juan de Fuca Ridge (physical properties)

-Establishing a new era of submarine volcanic observatories: Cabling Axial Seamount and the Endeavour Segment of the Juan de Fuca Ridge (using the ridge as a testing ground for live monitoring of seafloor activity?)

- Microearthquakes on the Endeavour segment of the Juan de Fuca Ridge (seismic activity along the ridge at the Endeavour segment)

Week 3

For your week 3 assignment you added a useful citation the Mid-Ocean Ridge page but gabbro forms below not above basalt William Wilcock (talk) 00:02, 17 April 2017 (UTC)

Critique Articles Week 2

This is a really thorough review of the two articles and easy to read - some of your fellow students put each review in a single long paragraph. I noticed that for the Convergent boundary article you stated that "plagiarism almost certainly occurred in this article, as it lacks citations for every fact but one" - I do not think that is quite correct - Google defines plagarism as "the practice of taking someone else's work or ideas and passing them off as one's own" and while the author has not cited the source of the ideas in the article, there is no pretense that they are the authors own so unless the author is taking words or organization directly from another source, I do not think it is plagiarized. It is just really sloppy for not to cite sources. William Wilcock (talk) 05:45, 10 April 2017 (UTC)

Plate Tectonics Is each fact referenced with an appropriate, reliable reference?

• Some places references may be incorrectly placed,

Is everything in the article relevant to the article topic? Is there anything that distracted you?

• I think this is a very complicated topic which warrants an extensive article page.
• The topics were well organized in order of importance, such as the main theory first, and additional information other people may find irrelevant or not important towards the end. For example, coming into this article I had never thought of tectonics on planets other than Earth, but the section on extraterrestrial tectonics was intriguing and caused me to want to know more.

Is the article neutral? Are there any claims, or frames, that appear heavily biased toward a particular position?

• Because the theory of plate tectonics is accepted nowadays, there was little I saw that would warrant debate, which makes this article more facts based than position based.
• there are attempts by authors to cite themselves. More on this in the talk page section.

Where does the information come from? Are these neutral sources?

• All sources I looked at appeared to be from reliable scientific sources.
• Some sources, such as reference 72 (Thompson "On the Secular Cooling of the Earth") was located on sites which required registration to access fully, which is not good etiquette for article writing.
• The sources I looked at further appear to be from reputable journals, and though there are a few areas of debate (such as the importance of gravitational pull of the sun and moon on plate movement), no one side is over-represented, and the article acknowledges that this topic is one which is being debated.

Are there sub-topics that are overrepresented, underrepresented or missing?

• Section 4, regarding the theory of Plate tectonics seems to be overly represented, and I don't think it needs to have as many subsections as it does. For example, magnetic striping (4.5) could be merged into the Mid-Oceanic Ridge Spreading section (4.4), because magnetic striping is observed at the mid-ocean ridges, these two could be merged without compromising or leaving out information.

Do the illustrations and images add to the article and are there illustrations/images that could be usefully added?

• There are 11 images, which I think all work well to improve the article without being overused.
• The image of Alfred Wegener in the 'continental drift' section does nothing to improve the information presented, but it does help to break up the monotony of nothing but text.
• Almost all images were maps or diagrams of faults and plate movement, which I find extremely helpful in visualizing what is being discussed in the article.

Check the "talk" page - what conversation is the Wikipedia community having behind the scenes about how to represent these topics?

• there are instances of authors citing themselves, which could affect neutrality or make claims without an independent source. On the talk page under 'Semi-protected edit request on 14 December 2015' user Nabliswedan tries to use information from an article which he wrote. He was called out by user Vsmith who accurately said, "No, Wikipedia is not here to promote your work" and declined the edit.

What is the article rated?

• B class article, which is defined by Wikipedia as "mostly complete and without major problems, but requires some further work to reach good article standards."

Convergent boundary

Is each fact referenced with an appropriate, reliable reference?

• Absolutely not. There is only one citation in the entire article, attributed to one sentence regarding deformation of the Asian continent.
• This single citation links to what looks to be a blog or webpage hosted by the University of Leeds, but there are no references to who is writing or where they have gotten their information. This ads doubt to the reliability of this only cited source.

Is everything in the article relevant to the article topic? Is there anything that distracted you?

• It all appears to be relevant, however the format seems jumbled and confusing to process.

Is the article neutral? Are there any claims, or frames, that appear heavily biased toward a particular position?

• It reads as if one person wrote the article, which would detract from neutrality. The lack of sources for the information does not help to establish neutrality either, however no bold claims are made which I would think require debate.

Where does the information come from? Are these neutral sources?

• There is only one source, which appears very factual. However because we don't know where that information came from, or the rest of the information in the article, we cannot truly evaluate the neutrality of this article.

Are there sub-topics that are overrepresented, underrepresented or missing?

• An explanation of how plates move (brief overview of plate tectonics) could be very useful in this article.

Do the illustrations and images add to the article and are there illustrations/images that could be usefully added?

• Illustrations of plate subduciton are useful, however the addition of maps and more detailed diagrams (such as ones which show the features of a subduction zone) could certainly improve this article.

Check a few citations. Do the links work? Is there any close paraphrasing or plagiarism in the article?

• the link works, and no plagiarism seems to have occurred with the one source cited
• plagiarism almost certainly occurred in this article, as it lacks citations for every fact but one.

Is any information out of date? Is anything missing that could be added?

• citations desperately need to be added
• There is one link to Earthquakes in the beginning, however this article should include its own section on Earthquakes because of how many earthquakes occur along convergent boundaries and the very real dangers some people living along coastlines face because of this.

Check the "talk" page - what conversation is the Wikipedia community having behind the scenes about how to represent these topics?

• the only entrance in the talk page is from our own class, one of my classmates commenting on the lack of citations

What is the article rated?

• The article is classified as a 'start class', which is an "article that is developing, but which is quite incomplete" according to Wikipedia's rating scale.

How does the way these subjects are discussed on Wikipedia differ from how they have been discussed in your prior Earth Science classes?

• Subduction zones are heavily covered in other geology classes I have taken due to us living on the Cascadia Subduction zone. Compared to those classes, this article is a brief overview, though nowhere near as in depth as my other classes have gone.

Iborche (talk) 05:33, 8 April 2017 (UTC)

Week 1

ocean //makes stuff bold ocean //llinks stuff sea //links stuff to other stuff (sea directs to ocean)