Sill propagation and climbing in layered crystalline host-rocks: Examples from saucer-shaped sills of the Faroe Islands
Mafic sills/dolerites, commonly occurring in layered sedimentary and crystalline settings worldwide, may occur as sub-lateral sheets or as saucer-shaped bodies. Values and distributions of Young’s Modulus within their ambient host-rocks determine their mode of emplacement. Current models o...
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2024
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crescholarship:10.31223/x5s691 2024-06-23T07:52:38+00:00 Sill propagation and climbing in layered crystalline host-rocks: Examples from saucer-shaped sills of the Faroe Islands Hansen, Jogvan 2024 http://dx.doi.org/10.31223/x5s691 unknown California Digital Library (CDL) posted-content 2024 crescholarship https://doi.org/10.31223/x5s691 2024-05-24T13:23:15Z Mafic sills/dolerites, commonly occurring in layered sedimentary and crystalline settings worldwide, may occur as sub-lateral sheets or as saucer-shaped bodies. Values and distributions of Young’s Modulus within their ambient host-rocks determine their mode of emplacement. Current models on development of saucer-shaped sills depict either melt propagation from single sources along sub-lateral relatively weak layers, from which they abruptly climb/transgress through stronger layers at intervals, or they may evolve by radial melt propagation/intrusion from one or more sources, while gradually/continuously ascending/climbing through strong and weak layers alike. The first model invokes involvement of sill overburdens and overlying free surfaces, while the latter envisages closed igneous systems where host-rocks both above and below the advancing magmas are affected without involvement of overlying free surfaces. Margins of saucer-shaped sills, cropping out in the Faroe-Islands, offer new insight of sill evolvement in layered crystalline host-rocks. This study strongly suggests that the slightly upward-curving geometries of these sills stem from radial propagation/intrusion of thin magma fronts. Their melts likely propagated as lobes or thin magma-fingers in a mole-like fashion, without noticeably affecting the overlying free surfaces prior to the main inflation phases. Other/Unknown Material Faroe Islands eScholarship Repository (University of California) Faroe Islands |
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eScholarship Repository (University of California) |
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description |
Mafic sills/dolerites, commonly occurring in layered sedimentary and crystalline settings worldwide, may occur as sub-lateral sheets or as saucer-shaped bodies. Values and distributions of Young’s Modulus within their ambient host-rocks determine their mode of emplacement. Current models on development of saucer-shaped sills depict either melt propagation from single sources along sub-lateral relatively weak layers, from which they abruptly climb/transgress through stronger layers at intervals, or they may evolve by radial melt propagation/intrusion from one or more sources, while gradually/continuously ascending/climbing through strong and weak layers alike. The first model invokes involvement of sill overburdens and overlying free surfaces, while the latter envisages closed igneous systems where host-rocks both above and below the advancing magmas are affected without involvement of overlying free surfaces. Margins of saucer-shaped sills, cropping out in the Faroe-Islands, offer new insight of sill evolvement in layered crystalline host-rocks. This study strongly suggests that the slightly upward-curving geometries of these sills stem from radial propagation/intrusion of thin magma fronts. Their melts likely propagated as lobes or thin magma-fingers in a mole-like fashion, without noticeably affecting the overlying free surfaces prior to the main inflation phases. |
format |
Other/Unknown Material |
author |
Hansen, Jogvan |
spellingShingle |
Hansen, Jogvan Sill propagation and climbing in layered crystalline host-rocks: Examples from saucer-shaped sills of the Faroe Islands |
author_facet |
Hansen, Jogvan |
author_sort |
Hansen, Jogvan |
title |
Sill propagation and climbing in layered crystalline host-rocks: Examples from saucer-shaped sills of the Faroe Islands |
title_short |
Sill propagation and climbing in layered crystalline host-rocks: Examples from saucer-shaped sills of the Faroe Islands |
title_full |
Sill propagation and climbing in layered crystalline host-rocks: Examples from saucer-shaped sills of the Faroe Islands |
title_fullStr |
Sill propagation and climbing in layered crystalline host-rocks: Examples from saucer-shaped sills of the Faroe Islands |
title_full_unstemmed |
Sill propagation and climbing in layered crystalline host-rocks: Examples from saucer-shaped sills of the Faroe Islands |
title_sort |
sill propagation and climbing in layered crystalline host-rocks: examples from saucer-shaped sills of the faroe islands |
publisher |
California Digital Library (CDL) |
publishDate |
2024 |
url |
http://dx.doi.org/10.31223/x5s691 |
geographic |
Faroe Islands |
geographic_facet |
Faroe Islands |
genre |
Faroe Islands |
genre_facet |
Faroe Islands |
op_doi |
https://doi.org/10.31223/x5s691 |
_version_ |
1802643998436753408 |