User:JessicaDickson/sandbox

Respond to you Peer Reviews

The peer reviews suggest that I bold my headings to make it more obvious, organize the whole article overall, adding an italic format to make it easier to show what I am changing and adding linked references to my additional sections added.

Bolded Headings and Adding References to New Sections

History

The initial recovery of platinum in South Africa took place on several of the large East Rand gold mines and the first separate platinum mine was a short lived venture near Naboomspruit that worked very patchy quartz reefs. The discovery of the Bushveld Igneous Complex deposits was made in 1924 by a Lydenburg district farmer, A F Lombaard.[3][4] This was an alluvial deposit but its importance was recognised by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930. Extensive mining of the Reef did not take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy.

Composition

The UG2 Reef, the composition of which is relatively consistent throughout the BIC, is rich in chromite, but lacks the Merensky's gold, copper and nickel by-products, though its reserves may be almost twice those of the Merensky Reef. Chromitite layers occur commonly in large mafic layered intrusions. A current theory is that chromitites form as a result of introduction and mixing of chemically primitive magma with a more evolved magma, which leads to supersaturation of chromite in the mixture, which in turn leads to the formation of a nearly monomineralic layer on the magma chamberfloor. The leading theory regarding the formation of the Merensky reef is that of crystals originating from a main magma source accumulated and cooled as the magma rose resulting in crystallization.[5] Yet the nature of crystallization is complex.

Layers

The Merensky Reef is constructed by 5 different layers. The first layer is mottled anorthosite which is pyroxene oikocrysts and is described as dark colored bands. The mottled anorthosite is composed of traces of quartz, titanite and apatite minerals. The second layer is Merensky chromitites which are highly irregular grains of basal chromitite. The third layer is similar to the second layer with Merensky chromitites, however the basal chromitite is compact and smaller in size. The fourth layer is Merensky pegmatite and is composed of coarse-grained silicate with an approximate thickness of 2.6 cm thick. In the fourth layer, chromite is sparse and sulphides are present. The fifth layer is Merensky melanorite and is a fine-grained chalcopyrite, quartz and feldspar rich matrix.

Whole-Rock Chemistry

The Merensky Reef has a high concentration of chromitites. However, the chromitites differ from one another in their levels of iridium, ruthenium, rhodium and platinum present. There is reported trace element enrichment shown by arsenic, cadmium, tin and tellurium.

Crystallization

There are several theories that suggest how the crystallization on the Merensky Reef occurred. One theory suggests the chromite crystallization originated from hybrid melts and lateral mixing. There is another theory that suggests the crystallization originated from chromite and sulphide droplets. However, there is another theory the crystallization originated from emplaced magma merging with roof-rock melts.

Adding an italic format to make it easier to show what I am changing instead of having two paragraphs.

References: The Reef is 46cm thick and bounded by thin chromite seams or stringers .[1]

The Reef is 46cm thick and bounded by thin chromite seams or stringers [2][4]

 This was an alluvial deposit but its importance was recognised by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930

This was an alluvial deposit but its importance was recognised by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930. [4]

''Extensive mining of the Reef did not take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy.''

Extensive mining of the Reef did not take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy. [4]

''Chromitite layers occur commonly in large mafic layered intrusions. A current theory is that chromitites form as a result of introduction and mixing of chemically primitive magma with a more evolved magma, which leads to supersaturation of chromite in the mixture, which in turn leads to the formation of a nearly monomineralic layer on the magma chamberfloor.''

Chromitite layers occur commonly in large mafic layered intrusions. A current theory is that chromitites form as a result of introduction and mixing of chemically primitive magma with a more evolved magma, which leads to supersaturation of chromite in the mixture, which in turn leads to the formation of a nearly monomineralic layer on the magma chamberfloor. [2]

Spelling and Rewording:

''This was an alluvial deposit but its importance was recognised by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930. '' This was an alluvial deposit but it’s importance was recognized by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930.

''Extensive mining of the Reef did not take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy.''

Extensive mining of the Reef didn’t take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy.

The UG2 Reef, the composition of which is relatively consistent throughout the BIC, is rich in chromite, but lacks the Merensky's gold, copper and nickel by-products, though its reserves may be almost twice those of the Merensky Reef.

The UG2 Reef composition is relatively consistent throughout the BIC and is rich in chromite, However, the UG2 Reef lacks the Merensky's gold, copper and nickel by-products, though it’s reserves may be almost twice those of the Merensky Reef.

A current theory is that chromitites form as a result of introduction and mixing of chemically primitive magma with a more evolved magma, which leads to supersaturation of chromite in the mixture, which in turn lead to the formation of a nearly monomineralic layer on the magma chamber floor.

A current theory suggests chromitites form as a result of the introduction and mixing of chemically primitive magma with a more evolved magma, which results in supersaturation of chromite in the mixture and the formation of a nearly monomineralic layer on the magma chamber floor.

copied from Merensky Reef

Rough Draft: Additions and Edits

References:

The Reef is 46cm thick and bounded by thin chromite seams or stringers .[1]

The Reef is 46cm thick and bounded by thin chromite seams or stringers [2][4]

This was an alluvial deposit but its importance was recognised by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930

This was an alluvial deposit but its importance was recognised by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930. [4]

Extensive mining of the Reef did not take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy.

Extensive mining of the Reef did not take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy. [4]

Chromitite layers occur commonly in large mafic layered intrusions. A current theory is that chromitites form as a result of introduction and mixing of chemically primitive magma with a more evolved magma, which leads to supersaturation of chromite in the mixture, which in turn leads to the formation of a nearly monomineralic layer on the magma chamberfloor.

Chromitite layers occur commonly in large mafic layered intrusions. A current theory is that chromitites form as a result of introduction and mixing of chemically primitive magma with a more evolved magma, which leads to supersaturation of chromite in the mixture, which in turn leads to the formation of a nearly monomineralic layer on the magma chamberfloor. [2]

Headings:

History

The initial recovery of platinum in South Africa took place on several of the large East Rand gold mines and the first separate platinum mine was a short lived venture near Naboomspruit that worked very patchy quartz reefs. The discovery of the Bushveld Igneous Complex deposits was made in 1924 by a Lydenburg district farmer, A F Lombaard.[3][4] This was an alluvial deposit but its importance was recognised by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930. Extensive mining of the Reef did not take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy.

Composition

The UG2 Reef, the composition of which is relatively consistent throughout the BIC, is rich in chromite, but lacks the Merensky's gold, copper and nickel by-products, though its reserves may be almost twice those of the Merensky Reef. Chromitite layers occur commonly in large mafic layered intrusions. A current theory is that chromitites form as a result of introduction and mixing of chemically primitive magma with a more evolved magma, which leads to supersaturation of chromite in the mixture, which in turn leads to the formation of a nearly monomineralic layer on the magma chamberfloor. The leading theory regarding the formation of the Merensky reef is that of crystals originating from a main magma source accumulated and cooled as the magma rose resulting in crystallization.[5] Yet the nature of crystallization is complex.

Spelling and Rewording:

This was an alluvial deposit but its importance was recognised by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930.

This was an alluvial deposit but it’s importance was recognized by Hans Merensky whose prospecting work discovered the primary source in the Bushveld Igneous Complex and traced it for several hundred kilometres by 1930.

Extensive mining of the Reef did not take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy.

Extensive mining of the Reef didn’t take place until an upsurge in the demand for platinum group metals used in exhaust pollution control in the 1950s, made exploitation economically feasible. Extraction of metals from the UG2 chromitite could only take place in the 1970s with major advances in metallurgy.

The UG2 Reef, the composition of which is relatively consistent throughout the BIC, is rich in chromite, but lacks the Merensky's gold, copper and nickel by-products, though its reserves may be almost twice those of the Merensky Reef.

The UG2 Reef composition is relatively consistent throughout the BIC and is rich in chromite, However, the UG2 Reef lacks the Merensky's gold, copper and nickel by-products, though it’s reserves may be almost twice those of the Merensky Reef.

A current theory is that chromitites form as a result of introduction and mixing of chemically primitive magma with a more evolved magma, which leads to supersaturation of chromite in the mixture, which in turn leads to the formation of a nearly monomineralic layer on the magma chamber floor.

A current theory suggests chromitites form as a result of the introduction and mixing of chemically primitive magma with a more evolved magma, which results in supersaturation of chromite in the mixture and the formation of a nearly monomineralic layer on the magma chamber floor.

Additional information:

Layers

The Merensky Reef is constructed by 5 different layers. The first layer is mottled anorthosite which is pyroxene oikocrysts and is described as dark colored bands. The mottled anorthosite is composed of traces of quartz, titanite and apatite minerals. The second layer is Merensky chromitites which are highly irregular grains of basal chromitite. The third layer is similar to the second layer with Merensky chromitites, however the basal chromitite is compact and smaller in size. The fourth layer is Merensky pegmatite and is composed of coarse-grained silicate with an approximate thickness of 2.6 cm thick. In the fourth layer, chromite is sparse and sulphides are present. The fifth layer is Merensky melanorite and is a fine-grained chalcopyrite, quartz and feldspar rich matrix.

Hutchinson, D, et al. “Concentration of particulate platinum-Group minerals during magma emplacement; a case study from the Merensky Reef, Bushveld Complex.” Journal of Petrology, 1 Jan. 1970, ecite.utas.edu.au/98142.

Whole-Rock Chemistry

The Merensky Reef has a high concentration of chromitites. However, the chromitites differ from one another in their levels of iridium, ruthenium, rhodium and platinum present. There is reported trace element enrichment shown by arsenic, cadmium, tin and tellurium.

Hutchinson, D, et al. “Concentration of particulate platinum-Group minerals during magma emplacement; a case study from the Merensky Reef, Bushveld Complex.” Journal of Petrology, 1 Jan. 1970, ecite.utas.edu.au/98142.

Crystallization

There are several theories that suggest how the crystallization on the Merensky Reef occurred. One theory suggests the chromite crystallization originated from hybrid melts and lateral mixing. There is another theory that suggests the crystallization originated from chromite and sulphide droplets. However, there is another theory the crystallization originated from emplaced magma merging with roof-rock melts.

Scoon, R. N., & Teigler, B. (1994). Platinum-group element mineralization in the critical zone of the western Bushveld Complex; I, Sulfide poor-chromitites below the UG-2. Economic Geology, 89(5), 1094-1121. doi:10.2113/gsecongeo.89.5.1094

Naldrett, A., Kinnaird, J., Wilson, A., Yudovskaya, M. & Chunnett, G. (2011). Genesis of the PGE-enriched Merensky Reef and chromitite seams of the Bushveld Complex. In: Li, C. & Ripley, E. M. (eds) Magmatic Ni–Cu and PGE Deposits: Geology, Geochemistry and Genesis. Reviews in Economic Geology 17, 235–296.

Kinnaird, J. A, Kruger, F. J., Nex, P. A. M. & Cawthorn, R. G. (2002). Chromite formation—a key to understanding processes of platinum enrichment. Transactions of the Institution of Mining and Metallurgy 111, B23–B35.

Merensky Reef

Jessica Dickson, Assignment done alone.

Contribution:

The first source is referenced incorrectly and does not support what is stated. The article says “The Reef is 46cm thick” and is linked to the first reference in the list. However, this claim is made in the fourth reference and was not found in the first reference. In addition, the link for the fourth reference is not working. These problems could be improved with proper referencing throughout the article, more references throughout the article to support the claims and further checking the entire article for any other mistakes.

The article has no structural headings, all the information is found under one big paragraph and it would be easier to locate specific information with headings. This could be improved by separating the information and adding heading in the article such as origin, composition and history.

There could be addition information about the crystallization process. The article cuts off at “Yet the nature of crystallization is complex.”. This could be improved with added information about the proposed models and theories for the concentration of PGE in the Reef, and the possible importance of sulphide. There could be addition information about the theories of the composition of the Merensky reef such as sulphides, silicates and chromites. This added information could benefit the article for a better understanding of the Merensky reef.

Lastly, the word choices and flow of article is poorly chosen. This could be improved by fixing spelling mistakes such as “recognised”. The article could be improved by proper and consistent punctuation because there is a lot of it’s and its. This improved would help the article because it would be easier to read and understand.

Bibliography:

Ballhaus, Chris, and Paul Sylvester. “Noble Metal Enrichment Processes in the Merensky Reef, Bushveld Complex.” Journal of Petrology, vol. 41, no. 4, 1 Apr. 2000, pp. 545–561., doi:10.1093/petrology/41.4.545.

Boudreau, Alan E. “Modeling the Merensky Reef, Bushveld Complex, Republic of South Africa.” Contributions to Mineralogy and Petrology, vol. 156, no. 4, 2008, pp. 431–437., doi:10.1007/s00410-008-0294-0.

Cawthorn, R.g. “A stream sediment geochemical re-Investigation of the discovery of the platiniferous Merensky Reef, Bushveld Complex.” Journal of Geochemical Exploration, vol. 72, no. 1, Jan. 2001, pp. 59–69., doi:10.1016/s0375-6742(00)00163-1.

Hutchinson, D, et al. “Concentration of particulate platinum-Group minerals during magma emplacement; a case study from the Merensky Reef, Bushveld Complex.” Journal of Petrology, 1 Jan. 1970, ecite.utas.edu.au/98142. Latypov, Rais, et al. “Field Evidence for the In Situ Crystallization of the Merensky Reef | Journal of Petrology | Oxford Academic.” OUP Academic, Oxford University Press, 10 July 2015, academic.oup.com/petrology/article/56/12/2341/2375423/Field-Evidence-for-the-In-Situ-Crystallization-of.

Naldrett, A. J., et al. “PGE Tenor and Metal Ratios within and below the Merensky Reef, Bushveld Complex: Implications for its Genesis | Journal of Petrology | Oxford Academic.” OUP Academic, Oxford University Press, 20 Apr. 2009, academic.oup.com/petrology/article-lookup/doi/10.1093/petrology/egp015.

Smith, Damian S., and Ian J. Basson. “Shape and distribution analysis of Merensky Reef potholing, Northam Platinum Mine, western Bushveld Complex: implications for pothole formation and growth.” Mineralium Deposita, vol. 41, no. 3, 2006, pp. 281–295., doi:10.1007/s00126-006-0059-5.

Article evaluation Chromite

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

Everything in the article is relevant to the article topic and nothing has distracted me in the article.

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

The article is neutral and does not take appear to have any biased toward a particular position.

Are there viewpoints that are overrepresented, or underrepresented?

I feel the article is very underrepresented in characteristics such as physical properties, mechanical properties, phase diagrams, solid solutions, occurrence such as stratiform or podiform deposits, uses and perhaps some history such as just general and even etymology.

Check a few citations. Do the links work? Does the source support the claims in the article?

The first link I tried was a journal with a specific page number, the link works but the source does not support the claims in the article. The second link I tried was linked to a YouTube channel with no specific video therefore the source did not support the claims in this article. The third link I tried was a website and the website had no information about chromite or the any sorts of supporting claims in the article.

Is each fact referenced with an appropriate, reliable reference?

There is not appropriate or reliable references supporting the “facts”.

Where does the information come from? Are these neutral sources? If biased, is that bias noted?

The information is coming from several sources, websites, journals, books and youtube videos. There is bias noted.

Is any information out of date? Is anything missing that could be added? After reviewing it, there is no out of date information. Although, there is a lot of new information that could be added under the Mining heading since the last update is in 2010.

There is new information that could be physical properties, mechanical properties, phase diagrams, solid solutions, occurrence such as stratiform or podiform deposits, uses and perhaps some history such as just general and even etymology.

Check out the Talk page of the article. What kinds of conversations, if any, are going on behind the scenes about how to represent this topic?

On the Talk page, there are conversations about Chromite in Canada, How it is used and if there is need for a disambig page or not.

How is the article rated? Is it a part of any WikiProjects?

The article is not rated. This article is apart of WikiProject Geology, WikiProject Mining and WikiProject Rocks and Minerals.