Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Rcrust : a tool for calculating path-dependent open system processes and application to melt loss
ENGLISH ABSTRACT: Earth‘s continental crust is stabilised by crustal differentiation that is driven by partial melting and melt loss: Magmas segregate from their residuum and migrate into the upper crust, leaving the deep crust refractory. Thus, compositional change is an integral part of the met...
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | en_ZA |
| Published: |
Stellenbosch : Stellenbosch University
2016
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867614079028297728 |
|---|---|
| access_status_str | Open Access |
| author | Mayne, Matthew Jason |
| author2 | Stevens, Gary |
| author_browse | Mayne, Matthew Jason Stevens, Gary |
| author_facet | Stevens, Gary Mayne, Matthew Jason |
| author_sort | Mayne, Matthew Jason |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | ENGLISH ABSTRACT: Earth‘s continental crust is stabilised by crustal differentiation that is driven by partial
melting and melt loss: Magmas segregate from their residuum and migrate into the upper
crust, leaving the deep crust refractory. Thus, compositional change is an integral part of the
metamorphic evolution of anatectic granulites. Current thermodynamic modelling
techniques have limited abilities to handle changing bulk composition. New software is
developed (Rcrust) that via a path-dependent iteration approach enables pressure,
temperature and bulk composition to act as simultaneous variables. Path-dependence allows
phase additions or extractions that will alter the effective bulk composition of the system.
This new methodology leads to a host of additional investigative tools. Singular paths within
Pressure-Temperature-Bulk composition (P-T-X) space give details of changing phase
proportions and compositions during the anatectic process, while compilations of paths
create path-dependent P-T mode diagrams. A case study is used to investigate the effects of
melt loss in an open system for a pelite starting bulk composition. The study is expanded
upon by considering multiple P-T paths and considering the effects of a lower melt
threshold. It is found that, for the pelite starting composition under investigation, open
systems produce less melt than closed systems and that melt loss prior to decompression
drastically reduces the ability of the system to from melt upon decompression. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/98358 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:46:20.037Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/98358 Rcrust : a tool for calculating path-dependent open system processes and application to melt loss Mayne, Matthew Jason Stevens, Gary Moyen, Jean-Francois Stellenbosch University. Faculty of Science. Dept. of Earth Sciences. Rcrust UCTD Earth (Planet) -- Crust Metamorphism (Geology) ENGLISH ABSTRACT: Earth‘s continental crust is stabilised by crustal differentiation that is driven by partial melting and melt loss: Magmas segregate from their residuum and migrate into the upper crust, leaving the deep crust refractory. Thus, compositional change is an integral part of the metamorphic evolution of anatectic granulites. Current thermodynamic modelling techniques have limited abilities to handle changing bulk composition. New software is developed (Rcrust) that via a path-dependent iteration approach enables pressure, temperature and bulk composition to act as simultaneous variables. Path-dependence allows phase additions or extractions that will alter the effective bulk composition of the system. This new methodology leads to a host of additional investigative tools. Singular paths within Pressure-Temperature-Bulk composition (P-T-X) space give details of changing phase proportions and compositions during the anatectic process, while compilations of paths create path-dependent P-T mode diagrams. A case study is used to investigate the effects of melt loss in an open system for a pelite starting bulk composition. The study is expanded upon by considering multiple P-T paths and considering the effects of a lower melt threshold. It is found that, for the pelite starting composition under investigation, open systems produce less melt than closed systems and that melt loss prior to decompression drastically reduces the ability of the system to from melt upon decompression. AFRIKAANSE OPSOMMING: Korsdifferensiasie stabiliseer die kontinentale kors van die aarde tydens gedeeltelike smelting. Magma segregeer van hul residuum en migreer in die vlakker kors in. As gevolg daarvan raak die diepkors meer vuurvas. Dus speel komposisionele verandering ‗n belangrike rol in die evolusie van anatektiese granuliete. Hedendaagse termodinamiese modelleringstegnieke het beperkte vermoëns om 'n veranderende grootmaatsamestelling te hanteer. Nuwe sagteware is ontwikkel (Rcrust) wat 'n roete-afhanklike iterasie benadering volg. Hierdie metode laat die druk, temperatuur en grootmaatsamestelling toe om as gelyktydige veranderlikes te funksioneer. Roete-afhanklikheid laat fasetoevoegings of ekstraksies toe om die effektiewe grootmaatsamestelling van die stelsel te verander. Die nuwe metode bied ‗n magdom verskeie maniere aan om ondersoek in te stel. Enkel roetes van P-T-X ruimte beskryf die fase proporsies en komposisies tydens die proses anatektiese, terwyl kombinasies van roetes, roete-akhanklike pseudosections skep. 'n Gevallestudie is op uitgebrei om die gevolge van smeltverlies te ondersoek. Dit is bevind dat oop stelsels minder produktief by smelt vorming is as geslote stelsels, en dat dekompressie smelt minder produktief as verwarming is. Die verlies in smelt produktiwiteit van die oop stelsel impliseer beperkings op die maksimum massa dekompressie smelt wat kan vorm. Tektoniese modelle wat dekompressie smelt as bron van groot volumes smelt gebruik moet dus herevalueer word. 2016-03-09T14:09:44Z 2016-03-09T14:09:44Z 2016-03 Thesis http://hdl.handle.net/10019.1/98358 en_ZA Stellenbosch University 46, 26 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Rcrust UCTD Earth (Planet) -- Crust Metamorphism (Geology) Mayne, Matthew Jason Rcrust : a tool for calculating path-dependent open system processes and application to melt loss |
| title | Rcrust : a tool for calculating path-dependent open system processes and application to melt loss |
| title_full | Rcrust : a tool for calculating path-dependent open system processes and application to melt loss |
| title_fullStr | Rcrust : a tool for calculating path-dependent open system processes and application to melt loss |
| title_full_unstemmed | Rcrust : a tool for calculating path-dependent open system processes and application to melt loss |
| title_short | Rcrust : a tool for calculating path-dependent open system processes and application to melt loss |
| title_sort | rcrust a tool for calculating path dependent open system processes and application to melt loss |
| topic | Rcrust UCTD Earth (Planet) -- Crust Metamorphism (Geology) |
| url | http://hdl.handle.net/10019.1/98358 |
| work_keys_str_mv | AT maynematthewjason rcrustatoolforcalculatingpathdependentopensystemprocessesandapplicationtomeltloss |