User:Ailobao/sandbox

Week 5: First Draft

Intro: (Edited version of the current introduction)

The Cobb Hotspot is a marine volcanic hotspot located at (46˚ 00' 0.00" N, -130˚ 00' 0.00" W), which is 460km (290mi) west of North America, in the Pacific Ocean. The hotspot is also located on the Juan de Fuca Ridge and, over time, has created the Cobb-Eicklberg Seamount chain. The Axial Seamount is the hotspot's most recent eruptive center, which last erupted in 1998. The central ridge is thicker than the surrounding crust by one to two km and may be accumulated buildup from the hotspot, which is essentially an underwater volcano with a root twenty to forty kilometers in diameter, reaching a depth of 11 kilometres (6.8 mi) beneath the volcano. The magma flows at a rate of 0.3 to 0.8 m³/s. The caldera is 1,450 metres (4,760 ft) below sea level.

Cobb Hotspot and the Axial Seamount Chain:

The Cobb Hotspot has created an underwater mountain range that ranges 1800km to the Alaskan Trench. The oldest mount in the chain is the Marchland Mount, which ages 30 to 43 Ma (million yrs old). The older end of the chain ends at a subduction zone; therefore, the true age of the hotspot is difficult to determine as the oceanic crust is being subducted.

Geochemical and Physical Processes:

Derives from plumes of molten mantle that upwell to the crust of Earth, whether that be oceanic crust or continental. This movement of magma breaks through the upper mantle, or the lithosphere, and creates a volcanic spot. This does not mean that all volcanoes are hotspots. A plate can move over a hotspot, leaving a mountain chain in its wake. This is supported by the theory of plate tectonics. The peaks and mountains left behind are no longer active volcanoes. Hotspots do not necessarily occur on a plate boundary, however the Cobb Hotspot does.

Trace elements were used to discover that older mounts created by the Cobb Hotspot contained more minerals like olivine and augite. Younger mounts created by the hotspot contain more minerals like calcic plagioclase, augite and pigeonite; they contain little to no olivine. These characteristics are like those found in lava basalts recovered from the Juan de Fuca Ridge.

A recent study found that magmas from the spreading ridge and the hotpot have their differences. For one, they contain dissimilar concentrations of elements like Na₂O, CaO and Sr at a given mafic level. This difference highlights that the magmas were formed at different depths in the mantle. It is theorized that the hotspot magma was melted deeper than that of the Ridge. For these two masses to exist, the temperature of the magma at the Cobb Hotspot must be of a particular high temperature.

The Cobb Hotspot and the Juan de Fuca Ridge:

As mentioned previously, the magma supply of the two geologic features differ; so do their impacts on each feature. The magma supply to the Cobb Hotspot is more primitive than that of the rift magma. And, as the archaic magma flows beneath the magma chamber of the rift, it causes further melting and rapid cooling, which allows for fractional crystallization.

Week 4: Choosing a topic.

The Cobb Hotspot page only has a brief summary. I plan to expand upon this by adding and creating some subsections like: Geochemical and physical processes, Influence on the Axial seamount etc. Some process that are involved in however do have their own pages and so these wont be discussed in great detail, but they will be present with a link. The similarities between this hot spot and others do exist however there are some unique characteristics about the Cobb Hotspot that will be mentioned.

Possible Sources:

• Geochemical evolution & Geochemistry of Magma (Hotspots) and the Juan de Fuca Ridge
• Pacific Hotspots
• Lithospheric thinning
• Juan de Fuca ridge and the hotspot
• Geophysics

*It was very difficult to find other sources that aren't from scientific journals however, I am still searching.

This is a good start. Agreed regarding non journal sources. Could chat with the librarian. Yashwant Meghare (Yashmeghare) is doing the Cobb-Eickelberg Seamount Chain so this topic is close to yours. You are talking about the hotspot and Yashwant about the Seamount chain it produced although there will be overlap. William Wilcock (talk) 04:05, 24 April 2017 (UTC)"

Did you search Georef in the libraries page under "Research Articles and Databases" - this will give you many more research articles and they will probably be better sorted for relevance and you can then search for sub-topics. For instance you could find if the keller abstract led to a more detailed article William Wilcock (talk) 04:03, 24 April 2017 (UTC)"

The web site mantleplumes.org may be of interest although it does not seem to talk about the Cobb Hotspot specifically William Wilcock (talk) 04:03, 24 April 2017 (UTC)"

You might want to break this sandbox into sections and subsections with ==, === and ==== commands William Wilcock (talk) 04:09, 24 April 2017 (UTC)

A search on Google Books led me to a textbook with online access available through UW: The petrology, geochemistry, and geochronology of hotspot seamounts in the north Pacific and arc/backarc volcanism on the northern Antarctic Peninsula could be worth taking a look. Erik (talk) 14:03, 24 April 2017 (UTC)

Week 3: Adding to an Article.

Added to the Mid-ocean Ridge page: within the impacts section with a citation from National Geographic.

A good addition William Wilcock (talk) 22:43, 16 April 2017 (UTC)

Week 2: Critiquing Articles

Your critique is defensible but it is not very specific - for example, what sections might be usefully added to the Convergent Plate Boundaries page? Can you give an example of a section that is well organized and explain why you think it is. Also if you look through the class assignment there are a lot of issues to consider (article rating, talk page conversation, out of date citations, utility of illustrations etc.) that you do not consider" William Wilcock (talk) 05:00, 10 April 2017 (UTC)

Plate Tectonics:

• There are just enough citations with in the text however there are many works cited at the bottom of the page. These should reflect all the information found on the page.
• Sections and subsections of the article are well balanced and organized.
• The article also presents the information in an unbiased way using images to aid in explanation.

Convergent Plate Boundaries:

• This article lacks citations and work cited; this can cause people to view the information as invalid or unreliable.
• There could be more sections and subsections of the article that can shed light on more information.

-- See Convergent Plate Boundaries Talk page for Evaluation (extra credit)