Litteraturstudie: HIMU ursprung och framtid
(2024) In Examensarbeten i geologi vid Lunds universitet GEOL02 20241Department of Geology
- Abstract (Swedish)
- Sammanfattning: Mantelsignaturen HIMU ( High μ/ High U/Pb) som får sitt namn från dess höga 238U/204Pb innehåll är en av normalt fyra mantelsignaturer som är funnet på flera oceaniska basaltöar över världen så som St Helena. Ursprunget av detta material är okänt men flera hypoteser kring dess bildande finns, där de flesta verkar ha subdukterande oceanskorpa med i bildningsprocessen. Denna litteraturstu-dies mål är därmed att söka fram dessa olika hypoteser och diskutera vilken som är mest sannolik samt att svara på frågan, blir det mer HIMU i framtiden? Resultatet av dessa sökningar har primärt gett tre hypoteser kring HIMUs bildning. Dessa är; hypotes ett som placerar ursprunget i ovanliga och okända processer under subduktion av... (More)
- Sammanfattning: Mantelsignaturen HIMU ( High μ/ High U/Pb) som får sitt namn från dess höga 238U/204Pb innehåll är en av normalt fyra mantelsignaturer som är funnet på flera oceaniska basaltöar över världen så som St Helena. Ursprunget av detta material är okänt men flera hypoteser kring dess bildande finns, där de flesta verkar ha subdukterande oceanskorpa med i bildningsprocessen. Denna litteraturstu-dies mål är därmed att söka fram dessa olika hypoteser och diskutera vilken som är mest sannolik samt att svara på frågan, blir det mer HIMU i framtiden? Resultatet av dessa sökningar har primärt gett tre hypoteser kring HIMUs bildning. Dessa är; hypotes ett som placerar ursprunget i ovanliga och okända processer under subduktion av oceanskorpa. Dessa sällsynta processer kan ha inträffat bara enstaka till-fällen i jordens historia. Hypotes två som placerar ursprunget i en vanligare process under subduktion av oceanskorpa inkluderar berikning och kontamination från olika källor till exempel havsvatten tillsam-mans med partiell uppsmältning av den subdukterande oceanskorpan och kombination av partiell upp-smält mantel. Hypotes tre placerar HIMUs ursprung i arkeikum där den ska ha bildats genom metaso-matism med karbonater i den subkontinetala litosfäriska manteln. Det gemensamma mellan dessa hypo-teser är att HIMU måste ha isolerats och lagrats i manteln. Flera lagringslokaler har föreslagits, dessa är den djupa manteln och övergångszonen samt så låter hypotes tre HIMU-material även finnas under vissa delar av kontinentalskorpan i den övre manteln med mindre mängder. Resultaten av denna rapport har tagit fram ett flertal olika hypoteser kring HIMUs ursprung där jag tror att det är den andra hypotesen som är mest sannolik eftersom de mätningar som utförts på HIMU-material mest pekar på denna hypo-tes. Denna hypotes leder också till att HIMU kan bildas aktivt i dagens subduktionsprocesser vilket kan leda till mer HIMU i framtiden. (Less)
- Abstract
- Abstract:The mantle signature HIMU (High μ / High U/Pb) which gets its name from its high 238U/204Pb ratios is one of four mantelsignatures which is found on several oceanic basalt islands around the world such as St Helena. There are also several hypotheses about the origin of this HIMU material where most have subducted oceanic plates as part of the formation. The purpose of this literature analysis is therefore to search for different hypotheses and through this discuss the origin of HIMU and answer the question, will there be more HIMU in the future? The result of this search has led to three primary hypotheses about HIMUs origin. These are; hypothesis one which places the origin of HIMU in the subduction of the oceanic crust, This... (More)
- Abstract:The mantle signature HIMU (High μ / High U/Pb) which gets its name from its high 238U/204Pb ratios is one of four mantelsignatures which is found on several oceanic basalt islands around the world such as St Helena. There are also several hypotheses about the origin of this HIMU material where most have subducted oceanic plates as part of the formation. The purpose of this literature analysis is therefore to search for different hypotheses and through this discuss the origin of HIMU and answer the question, will there be more HIMU in the future? The result of this search has led to three primary hypotheses about HIMUs origin. These are; hypothesis one which places the origin of HIMU in the subduction of the oceanic crust, This with special, rare and unknown circumstances which may have only happened a few times in history. Hypothesis two which also places the origin of HIMU in the subduction processes of oceanic crust but combines it with enrichment and contamination from different sources such as ocean water and partial melting of the subducting plate as well as combination with partially melted mantle material. This hypothesis also lets the formation of HIMU be an active process today. Hypothesis three places the origin in the Archean geological period where it is hypothesized to have formed through me-tasomatosis with carbonates in the subcontinental lithospheric mantle. Common between all three hy-potheses are that HIMU must have been isolated and stored in the mantle and several storage locales have been proposed; these are primarily the deep mantle and the transition zone. The hypothesis that pla-ces the origin in the Archean also lets some HIMU exist under the continental crust in lesser degrees. Although the results of this rapport has given several hypotheses on the origin of HIMU I think the most convincing one is hypothesis two as the measurements taken on HIMU mostly points in its direction. This means that HIMU could actively be produced during subduction of oceanic crust and would also lead to the possibility of more HIMU in the future (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9158594
- author
- Persson, Viktor LU
- supervisor
- organization
- course
- GEOL02 20241
- year
- 2024
- type
- M2 - Bachelor Degree
- subject
- keywords
- Geologi, HIMU, Ursprung till HIMU, mantelsignaturer, Petrologi
- publication/series
- Examensarbeten i geologi vid Lunds universitet
- report number
- 680
- language
- Swedish
- id
- 9158594
- date added to LUP
- 2024-06-05 11:07:11
- date last changed
- 2024-06-05 11:07:11
@misc{9158594,
abstract = {{Abstract:The mantle signature HIMU (High μ / High U/Pb) which gets its name from its high 238U/204Pb ratios is one of four mantelsignatures which is found on several oceanic basalt islands around the world such as St Helena. There are also several hypotheses about the origin of this HIMU material where most have subducted oceanic plates as part of the formation. The purpose of this literature analysis is therefore to search for different hypotheses and through this discuss the origin of HIMU and answer the question, will there be more HIMU in the future? The result of this search has led to three primary hypotheses about HIMUs origin. These are; hypothesis one which places the origin of HIMU in the subduction of the oceanic crust, This with special, rare and unknown circumstances which may have only happened a few times in history. Hypothesis two which also places the origin of HIMU in the subduction processes of oceanic crust but combines it with enrichment and contamination from different sources such as ocean water and partial melting of the subducting plate as well as combination with partially melted mantle material. This hypothesis also lets the formation of HIMU be an active process today. Hypothesis three places the origin in the Archean geological period where it is hypothesized to have formed through me-tasomatosis with carbonates in the subcontinental lithospheric mantle. Common between all three hy-potheses are that HIMU must have been isolated and stored in the mantle and several storage locales have been proposed; these are primarily the deep mantle and the transition zone. The hypothesis that pla-ces the origin in the Archean also lets some HIMU exist under the continental crust in lesser degrees. Although the results of this rapport has given several hypotheses on the origin of HIMU I think the most convincing one is hypothesis two as the measurements taken on HIMU mostly points in its direction. This means that HIMU could actively be produced during subduction of oceanic crust and would also lead to the possibility of more HIMU in the future}},
author = {{Persson, Viktor}},
language = {{swe}},
note = {{Student Paper}},
series = {{Examensarbeten i geologi vid Lunds universitet}},
title = {{Litteraturstudie: HIMU ursprung och framtid}},
year = {{2024}},
}